A STUDY OF THE REACTION OF
DIMETHYL TERTiARY BUTYL
CARBINOL WITH BENZENE AND
ALUMINUM CHLORIDE

Thesis {Or the Degree OF M. S.
MICHIGAN STATE COLLEGE
Wayne Thomas Barrett
1942

'“:- f) q r) v
‘ ‘Ilkz'g !\

- Michigan State
L1 'Umversity f"

 

 

 

 

A STUQY g; 1.; ' --

 
   

 
 

01: D HY W gum]. cmmxoz.

T? Y) 2'? 9
“J." «Li

0"” 13::
Jill- &

     

‘3;le T '“hv'wrv Ev?

by
a... 13 mom 6 s Lamar:

A.Tfi3313

Suhnittcd to tho Gradusto School of Elohigun
State College of Agriculture and Applied

Science in partial fulfilment of tho
requirement. for the degree of

LASIER 0P SCIBHGE

Department of Chamiatry
1942

The author wishes to thank Dr. R. C, Huston

for his friendly criticism and advice.

331.607

TABLE OF COKTALTS

Introduction------ --------------------------------
Fractionating Column
Discussiono- ------- --g ----- g ----------- ------
Determination of Plate Value- --------------- ,-
-Historical--c-------------------------------------
Theoretical-------g---Q-----f ...... --- ..... --;---
Preparation of Dimethyl Tert.-buty1 Carbinol—-----
Experimental - Part I ----~-------~--------------~
Condensatione-----—--------------------------
Fractionation----~ ------ ---------------------
Identification of Fractiona--- ------- -----..-

Condensatione----- -------- -------------------
Table of Reeulte-------~------ .......... -----
Discussion ---------- --------------- ...... - ........
Summary------------------- ------ --- ........... ----

Bibliography-- ---------------------------- - ------ -

Page
1

(‘0

IETRODUC T 101‘;

Tim. finalisation. of tertiary alcohpls with. benzene-1n
the presence of aloninum.chlcride has been exteneively studied
in this laboratorye_ In the cone of bighiy'bronchedolcobols,
the yieldeof the expected_tertiary;elky1 benzene have been
lot; many other products being formed. :fhe object of_ihie
investigation is to eeparate and identify-come of these-pro-
ducts. _In order to accompliehthie,_a fractionating-column
with some epeeialpropcrtiee was eccential. so that more
or lose precise aeparotione of the variety of compounds

formed, could be made.

THE FRACTIOEATIEG COLULH

The design of any laboratory fractionating column-
mnst necessarily depend upon the particular type of sep-
station to be accomplished. Of course, it is desireable
in any column to have as high a separating power,~that is
plats value. as possible. Thus'with high plate values, a
mixture of two closely boiling liquids can be separated
quits completely by one distillation. .However, the type .
of distillation, the character-of the liquidsto be separated,
the amounts, and other practical considerations greatly ef-
fect the type_of column to be chosen.

From previous work it was known that the liquid to-be
distilled consisted of a mixture of hydrocarbons. some un-
saturated, and halogen containing-compounds. ~The amount
of liquid to be distilled varied from ten to one hundred-»¢»
milliliter8._ The boiling temperature ranged from 35 to well
over 200 degrees. Vacuum fractionation was necessary since
there was a good possibility that some of the compounds
decomposed when distilled at atmospheric-pressure.-

. From.ths above characteristics it was seen that-the;
column should be built for batch distillation, that is the :;
whole amount of the liguid.mixturc to be distilled'was placed
in the still pot at one time, the mixture slowly changing

composition as the more volatile componets were removed.

to

This is in contrast to the type column used industrially in
which a mixture of definite composition is slowly fed into
the column. It must be built for vacuum distillation and
designed so that there will be no heat loss from.the column.
Since semiousntitativc separations on small amoents of liquid
are to be msde,the column should have an overall low holdup.
The term holdup is defined as the number of cc of licuid
retained in the column and head durino distillation. Finally
the column should have a fairly high plate value.

Before entering into a discussion of the more common
type laboratory fractionating columns, some of the terms
generally used will be defined.

The term "plate Value" is frequently used in describ-

ing the ability of a column to separate two liquids by
means of their differences in vapor pressure. It is derived
from.a consideration of a column which is composed of a
series of theoretical plates each acting as a center of
equilibrium distillation, the vapors passing from any plate

to the plate above to be partially revaporized. This
continuous redistillation and recondensation, termed rectif-
ication, results in the concentration of the more volatile
liquid in the upner portion of the column. Thus a theo-
retical plate is a hypothetical apparatus which fulfills
the requirement that the vapor rising from a plate is in
equilibrium with the liquid leaving the plate. These

considerations make it necessary that there be no heat loss.

Many laboratory fractionsting columns are not composed
of actual distinct plates, The column may be packed with;
glass rings. spirals, ect., or it may be ebubble.csp~type,-
or unpacked, e.g. the Vigereux column. All of these deviceej
nerve as plates and the efficiency of the_column is therefore
described in terms of the number of theoretical plates it
contains.

The expression H.E.T.P. is commonly used to indicate
the relationship of the number of plates to the heightof'
the column, the_height equivalent for a theoretical plate.

The lower this value thermors efficient is the type of-pscking.

A factor greatly affecting the separating power of any
is the reflux ratio. iThie is defined as the moles of liquid
returned to the column over the moles of liquid removed as
product. With high reflux ratios the number of theoreticsl
plates apparently increases but the time required to collect
a definite quantity of liouid increases.

A large number of laboratory fractionating-columns --
have been described in the literature. The bubble cap-and
gauze plate type columns heveextremely low H.E.T.P.-but
the holdup of this type culumn is very considerable and they
are not suited for vacuum fractionation.

Of the packed columns, the Podbielniak packing, a close .
spiral extending the length of the column, is by far the best.
The holdup on this type packing is not greats~;lt has been
criticised for vscuum.work because of its tendency to from

slugs of liquid in the column.

The Vigereux type column has a low holdup and. if pro-
perly constructed, does not tend to slug. however. the H..
3.T.?. is rather high. It is ideal for micro-work.

The column chosen for this work was of the spinning
band type, similier to that described by lessons and loohte
(1). Baker. Berkenbus end Roswell (2) have also described
a column of this type. The column consists of a steel bend
spinning rapidly in en insulated glass tube. The holdup
per plate is the lowest of eny of the above types and the“

4'3. .P. is also low, comparing favorably with the bubble

cop type.

For this work, the head designed byӴhitmore (5) appeared
,to be the most satisfactory of the types that could be cone
atructed with facility. The Hhitmore heed was modified to
allow for the extension of the bend through it. This type
heed contains a stopcock by which the reflux ratio can be
regulated.

The insulation of the column is quite as important as
the packing. For vepor temperstures below 100 a silvered
Vacuum Jacket is quite sufficient. For higher temperatures
ordinary pipe COVcrlnL is used to supplement the vacuum
jacket. However. for best results. it was found necessary
to install a controlled electrical heating element the
length of the column. The heating element is controlled by
s.small transformer.

Because of the extreme fragility of the head of the

column. the take-off tube is supported by a motel connection

to the upper part of the column proper (not shown in the
aiaérau). The head is wrcpycc extensively with aabccioc
card to a §cint two cu.abovc the entrance of the thermometer
well. to incurc accurate thcrmoactcr rcucinga. incchutz
thermometers are used
The tau stopcocla throueh clich.thc organic liquids

pace are lubricated with a.hydrocarbcn insolublo'atopcock
arcccc.

. The slang bearing at.ihc top of the hccd through which
.the cad of the band was constructed very carefully. so as
to allGW'thc band to be crivcn and at the same time main-

taining a vacuum. %ith an ordinary glass hearing (A)
A ~To ”107%"
W

\o
-a6

E-

-—C— k-(QJ

 

 

L

[Sound
the rubber tube (3} which comgletea the vacuum seal is soon

worn through Because of the hihh external pressure. Kowcver

\

if the 51355 tube (i) 13 tcycred to the cxtcrncl aimmcicr

8-1

of the gluon tube from.thc hcna (C

q A
B

3.
Li #C

 

 

the ruhb;r lacta many times as long. The rubber to glass
moving joint is lubricated with.vcry small amounts of a

graphite suspension in glycerine.

 

 

 

 

 

  

rr\
thermometer seal
to
motor
A
H Full site View
of seal
vacuum

§JL V
g?

reciever

 

 

 

J

 

 

Spinning Band Fractionating Column

Height of column ~ 80 cm
Overall hei;ht - 135 cm
Scale .5 mm I 1 mm

The spinning band is made-of stainless steel and is-;--;
95 cm.long and 7 mm.wide. It is tapered to 3 mm at its upper
end. _ .., .4

The distillation pot is filled with glass wool to
:rrevent bumping. It is heated by a hot plate, the temp-
erature of which is accurately controlled by a 5 amp.
transformer.‘

The fraction cutter is designed so that-the reciever
can be removed and replaced by-enother without disturbing
the vacuum of the system. To accomplish this the systemxis
evacuated‘vith.stopcocks C and D open and A and.B closed.-;g
The fraction is collected and allowed to run into the reciever
by opening B. With E closed air is ellowed-to enter the
reciever by adjusting D. She rceiever is replaced with another.
C is closed and the reciever.evecuetcd by adjusting 3. until
the proper pressure is attained. C is-then opened and in‘.
this manner the distillation proceeds without interruption.
mummy

Several methods for-determining the plate value of -:3.
fractionating columns have been described in the literature.
The Thielc—HcCabc zrspnicsl method is one of-the simplest :-
and.mmct commonly used. 'This method was derived for columns
'which are actually made up of a series of plates but itcan
‘be applied.to columns of thespinning~band type if we view»-
the column as a series of segments each of which can be con-

aidcred as a plate.

Certain assumptions and conditions of distillation are

necessary for the application of this method. First. the
vapor possum; up the calm (V) on reaching the condenser
mat be all condensed. one portion returned to the column
as reflux or overflow (0) and the rest heirs: collected as
product (29}. The letters V. 0, and F refer to moles per
unit time. The column must be assumed to act adiabatically.
so must also assume constant vaporization and constant
overflow from any plate to the next. The column met operate
at constant rate of distillation and constant reflux ratio.
The composition of the mterial in the still pot and that
of the product must remain constant. This assumption is
only approached if the amourde of product are very smll as
compared with the amount of residue.

A diagram of a theoreticalcolmnn is shown below:

   

 

 

 

 

 

 

 

 

v condenser
P
1
2 Ir
3
x» V ha.
:1 T

 

 

The column is composed_of plate: 1.2, 3, n, and (n+1); o -;
coneonser and reflux return._ The term x refers to the mole
{routine of the more volatlle3componet in the liguid under
consideretiou: and, the term.y refers to the mole fraction
ofthe gore volatile conponet in the vapor-under consider.
etion.‘rf.io the composition of the product,_ _‘

. . For any plate the material leaving will equal that
entering it

(1) . V 'MO‘+ P

In tevme of the nmre valetile componet, for plate n

(2.) Vym 3 o xn—i—P 1,.

Eliminating V . .
P

(5) ynfl ‘ +63?) xn+ (W) xP

and in terms of reflux retio.R h 0/?
(“V y,“ a (if: 3 3E4? (ELI?) 3"
:xm and It" are-the only'rerioblee-end so the equation (4);;-
represents a etruight line of alope~(R/R+ij. this line boiné
celled the operating line. Since the slope cap-bc~ottaiued
fro-.the reflux ratio the line can be determined hy'eettbl-
iehinz e point on the-line. h ‘ _, .

w The 2- y equilibriun curve can be plotted from upe-
rflmental late.

I. O

7i
)2 ................

 
 
  

--—--'n-- ----

 

 

 

D

x

x

2‘
5..----_----
>( - -.._ ....
V

><

10

The composition of the reflux coming to the first plate
is the same as that of the product, x. = 1,. The papers

rising from this plate has the composition y;. Therefore

R
(s) y. - (M) an 1—(fi—E—f) x, _- xp

 

Since from.this equation y, 3 x4»the operating line must
intersect the x I y line at (x,,y,). The operating line
DC, is thus established.

Since y. is known, 1. can be calculated from the
equation of the operating line, and from.this we can obtain.
y, , and from.this x¢,ect. This procedure may be accomplished
graphically by merely drawing a series of horizontal and
vertical lines:between the operating line and the x-y equi-
librium curve, starting at.xp.

Each of these steps represents one perfect distillation
and so the total number of steps represents the number of
perfect plates in the column.

Thus, for the determination of plate value it is nec-
essary to know the reflux ratio, the composition of the
product-and the composition.cf the residues--

For this work, the binary system benzene-oarbon~tetra-
chloride was used. The composition of these mixtures is
readily established by-determining the refractive index.;
The data for the x-y equilibrium curve and the refractive
index-composition curve was that given by ZRWide1'(4)3"

The liquids used were Baker's-C.-P.,-dried-and care-
fully redistilled, a .1 degree fraction being used. ~The

refractive indices were determined by means of an Abbe'

ll

refractometer at 25.2 C. The values determined on known
mixtures checked well with the values given by Zawidzki.

The x, values in the table_following refer to the com-
position of the residue.. Samples of residue were removed
during distillation by means of a capillary-extending into
the still pot.> About .2 cc were collected as product.

The minimum.ref1ux ratio was calculated from.the slope
of the line intersecting the x l_y line at xp , and the

x-y equilibrium curve at Xf. The actual reflux ratio was

determined by comparing the rate at which the drops of
product came off the takeeoff tube and the bottom of the

 

 

 

 

 

column. The graph for the first determination is shown.
Table I

Trial _ l _ 2

Ref. Ind. 1.4950 1.4901

Ref. Ind.p 1.4719 1.4682

xp .642 .734

R 24:1 1831

min R 1931 2:1

Plate Value 25 24

ILEOTOPO 3.1 501 '

 

 

 

 

 

The holdup was determined by the method given by Tong-

berg, Fenske, and Quiggle (5). A known volume of a solution
of stearic acid in benzene of known concentration was refluxed
in the still. A sample was withdrawn from the still pot

and its composition determined. From.the change in con-

centration the volume of benzene in the column and head-
could be calculated. The stearic-acid-was assumed to-be-

nonvolatile at 80 C. The concentration was determined by

 

 

 

 

pipetting a two cc sample, evaporating_off the benzene

and weighing the residual stearic acid.

 

 

 

 

 

 

Table II p .e , .1
Before After After
reflux reflux draining

Weight stearic .0605 .0667 .0618
acid in 2 cc .0604 .0664 .0620
concentration .0602 .0332 .0310
volume of 23.0 20.6 22.6
liquid in

stillepot ' '

Holdup ‘ 2.4 cc .5
Holdup/plats .1 cc

 

 

 

 

 

 

The value: fetri fer holdup per plate agree well with
those found by lesccne and Lothe. The K.fl.T.F.. however
is somewhat hibher, probably because of the different type

heed used.

 

 

D'smaunm‘xox: or COLLPOSITIOI; FROLZ REFRACTIW-J 11m

(Benzene and 0014)

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Refractive
Index (t t 25.2) x
1. 494 ‘ ° °
\\
l. 492 3
\ N
10 490 k . 1
\\ Add these
“‘r-q . values to
1°488 7 those read
on the
sbcisss
1. 485 \ x<n2
\\
1.484 ‘22:-
N\
10478 k’.4
\
1.475 \
‘\
1.474 ' 5
‘ O
\ \
1. 470‘ >g: .e
\
1.468 '\
.00 .01 .02 .03 .04 .05 .06 .07 .08 .09 .10
Data 'Mols Fraction 0014
.0990 1.4936
.1579 1.4913
.2133 1.4891
.3061 1.4854
.4203 1.4808
.5131 1.4771
.6000 1.4736
.6831 1.4703
.7709 1.4667

DETERMINATION OF marshal}:

Eble fraction 0014

in vapor
.7

' y

 

.6

 

.5

 

 

 

 

 

.4

 

 

 

 

 

 

.3

 

.2__.

33

 

Ir

.1 ix
.1

Data for Equilibrium Curve
(Bensene and 0014)

 

|

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

ix
A L..—

 

X
.051
.117
.175
.253
.295
.396
.560
.674
.765

.2

y
.069
.146
.211
.292
Q 337
.439
.586
.693

.779.

.4 .5 .6 .7
Hole fraction 0014
in liquid - x
Data for Operating Line
Reflux ratio - 24:1

Slope - .963
If e 115

number of Plates - 25

‘.Uf.i, w
a
m.

13

Historical

The alhylaticn of arematic conpcunds with alcohols
has beau accomplished hy‘various condensing agents. A
short review of the use of aluminum chloride for this
purpose will follow.

The greater‘portion of the no 3 i n this field has
been done by fluaton and coaeorhere.

.fiuston and Friedmann cendensed benzyl alcohol {6),
~methyl, pheayl carbinol, ethyl, phezyl carbincl and hens-
hydrol with benzene. In addition to the eipected nah?
stituted benzene they found di- and tri-substituted ben-
zenes and in the case of aryl-alkyl carbinols they
found phenyl alkancs which were assumed to form by the
splitting off of one of the phenyl groups of the main
candensation product, the 1,1-diphenyl alkanes. They
also found that the ratio of one mole alcohol, five moles
benzene and one-half‘molc of aluminum chloride'pes op-

timum for the production of the main cendensatien aroduct.

.
Inc aging the amounts of aluminum.chloridc did not
increase she yields. higher temperatures gave acre of
the by-products.

Huston and Eager I?) attempted to condense 933‘ pri-
mary alcohols at room temperxture and with one-half mole

aluminum.chloride to one mole of alcohol. Under these

VII .1 . vAnflll‘D A.
._
T

14

conditions, methyl, ethyl, propyl, isoproyyl, butyl, iso~
butyl, and isoamyl alcohols did not give the alkyl benzenes.
Allyl alcohol did give the allyl benzene. Huston and Good-
emoot (8) condensed three cycloalkyl carbinols (-hexyl,
-pentyl, obutyl) and showed that the ease of condensation
was related to the strain in the ring: the greater strain
being more conducive to condensation.

Huston and others (é) have condensed tort.-butyl,
tert.-amyl, the three tert.-hexyl, the seven tert.—heyty1
and all of the tert.-octyl carbinols with benzene.

From these condensations it has been found that the
ratio of one mole of alcohol to one-half mole of aluminum
chloride is optimum.for the production of the corresponding
mono-alkyl benzene. As branching on the occarbon increases
the yields of the expected alkyl benzene decrease and un—
saturated compounds, halides and lower alkyl benzenes
form. Condensation at lower temperatures decreases the
amount of these side~products formed.' For example the
condensation of dimethyan-butyl carbinol save a 4? %
yield of z-methyl, 2-phenyl—hexane while condensation of
dimethyl tert.-butyl carbinol gave only a 7 % yield of
2,3,3-trimethyl, 2-phenyl butane.

CondenSation of dimethyl tert.-amyl carbinol gave,
in addition to the expected alkyl benzene, a 9 W yield
of tert.-butyl benzene. Dimethyl neo—amyl carbinol at
10 gave a 42 % yield of tert.-butyl benzene.

Most of above alcohols have also been condensed

with phenol (10}. The reaction, in general, setters to
proceed analeronsly. HoweVer two difi eren es axe to be
noted. The condensation, itself, proceeds with the reru
metiee of mere intense colors, and the yields of elk; l
phenols are much hinher. In no 6989,.ha8 there been re-
ported the formation of lower'moleeuler‘Weipnt elk 1
phenols.

Huston and Jackson (11) condensed several nlhyl-
diphenyi curbinols with phenol. l‘he primary elkyl~
diphenyl carbinols gave the expected products, the.sec-
ondary alkyl diphenyl carbinels have p-benz :Jl fihenel and
'secondary alhyl benzenes in addition to the ernected Drew
ducts. Tcrt.-butyl diphenvl cerbincl centensld t) Iive
the rearranged prednct; ,p-hbdrOXVphee ls r-dgpnen
Somethyl butane.

flushes, (13) sendensi.* same diflxl Jl-ary'l c Hrb nils
'Uith benzene reverted the 1 grantinn of din sf the cer-
resnendinr unsaturated products of the alcehels, in addi-
tlon to the expected di 7nhen;ll alxI:m es.

l’mye, Ian-ti stem-rs, (1(5) hive ccndcmsed Irma-'13; of the
secondary alcahels with Inn‘s e. ihe e;1u 111); s n: d fer
the condensation were seneuhut different fren these
zeentiewed above. Fifty pr: 8 (0.5 xeole) of allt' in
chloride'uere necded fir one-half male of alcohol. there
almainnn ch] eride decrees?! tr- .e 31:31.5“ In? .uene-elifg'l
benzene. ‘i‘no naiditlz'm of dry i101. thrmq‘hout t}: “it“:n

of alcohol increased the “ields. The nicehol was added

 

.41.?"1'
. lit... 4

to the suspension of aluminum chloride and benzene in an
ice bath. The mixture, in samo cases was refluxed for
several hours. .In many cases rearranged alkyl benzene“
wore formed.

Sovo a1 condensations of alcohols with obnor uro-
mutic sobstoncoo have been reported f?0J this luhjrotory (14).

Tookorvrmik Hawkommik 1:152 C'O-I?OZI’}IVI’S (13) have
royortod the cofidonootion of some of the lower yrlmwry,
secondary and tertiary alcohols mifih benzene and phenol.

The ratio of aluminum.chlorido to alcohol used by
thosO‘workors Hos varied. In gonoral, 1.5 to 2 UJIGS
aluminum ch orido por mole of Drinmry alcohol; 033 ole
aluminum chlorifia por.nolc of second ry alcohol; ugd, ono—
hulf'molo oluninum.chloride per'uolo tortiary alcohol
has boch used. inc mixturoo aftor tho midition of tro
aluminum chloride have boon refluxed several hours before
hydrolysis. filkonoa and alkyl halides havo boon isolutcd
as byE?DGUCt9 in the condensation of tertiary alcohols
with bouzone. Secondary alcohols gave no alkonos or alkyl
halides.

Several cyclic alcohols have also been condensed with
benzene by lsukorvunlk and co-uorkora (10). The olkanos
and alkyl halidos were again isolated as byproducts.

“01511 and 91111320 (1'7) have condensed some tom-lary-

aryl carbinols with benzene. They, also, report the formation
of tho corresponding alkcne of the corbinols and their sat-

unoted dimers.

.. .

IsA $1..» Ilw ‘

 

17 3|

Norris and co-workers (18) have condensed several *-
primary alcohols under conditions similiar to those used
by Tsukervanik. They report the formation of symmetri-
cal trl-alkyl bonzenos.
Ipatief and co-workers (19) have reported the con-
densation of n-proyyl alcohol with several condensing
agents. With aluminum chloride the unrearrangod product,
n-propyl benzene, was obtained. Hoo-pentyl alcohol also

gave the unrearrsngod alkyl benzene.

18

TlfliORILJT ICAL

The discussion of the theoretical aspects of the alkyl-
ation of benzene with alcohols must be closely related to
its alkylation with alkenes and alkyl halides, since all
act in a similiar manner to give the alkyl benzene. The
alkylation reaction by any of the three above alkylating
agents has been proposed to have a common ionic intermediate.
Or, the reaction of alcohols has been proposed to involve
slkenes and/or alkyl halides as intenmediates. Aluminum
chloride complexes with either the aromatic substance or
the alkylating agent have also been proposed as intermed-
iates.

The great activity of aluminum chloride with a wide
variety of substances has given data to support all of the
above types of mechanisms.

The direct removal of water from the alcohol and ben-
sens by the dehydrating agent, aluminum chloride, does not
explain the reaction characteristics, color, ect,, and the
rearranged products obtained.

The formation of alkenee as intermediates has been
assumed to explain the rearrangement of the alkyl groups
of certain alcohols. Thus primary alcohols have given sec-
ondary alkyl benzenes, and some ice-alcohols give tertiary

alkyl benzenee, e.g. isobutyl alcohol gives tert.-butyl

. l
1 9
!

benzene. The work of Kaye (13) with secondary alcohols.

in this laboratory has shown, that in every case where un-
saturation of the alcohol and subsequent addition of Hal

or benzene would, by the Earkonikow rule, lead to rearranged
products or mixtures of rearranged products, such products
have been found. Thus, butanol-Z gives the expected 2-phenyl
butane, while 2-methyl butanel-S gave the tertiary alkyl
benzene, 2-methyl, 2-phenyl butane. Heptanol-S gave mixtures
of the two secondary heptyl benzenes predicted by the above
concept.

KcKenna and Sowa, using boron triflouride as a catalyst
have proposed such a.mechanism.on the basis of the above
type rearrangements and the isolation of small amounts of
the alkenes and their polymers from.the products of the
reaction (20).

R-CIIz-CHQOEE _B_F3., R-CH - 0112

R-CH = 0112 +0536 -—-> R-cn(cfir15)-C}53

_ Welsh and Drake (l7) condensing tert.-ary1 carbinols

with phenol ahd benzene in the presence of alumunim chloride
have found analogous results. They have proposed a mech-
anism.similiar to that above. Enghes (12). in this labora-
tory, has condensed some dialkylaryl carhinols with benzene
and phenol and found, in addition to the expected diphenyl_
alkanes, dimers of the corresponding alkene of the alcohol.
The reduction product of the alcohol, 3-phenyl pentane in
the case of diethylphenyl carbinol was also obtained.

Jackson (11), in this laboratory, condensing diaryl-

 

Ellllilialill.|u
U, . ti“.-

.. al‘lJ‘.‘

1,0
alkyl carbinols has also noted the formation of the reduc-
tion product with some alcohols. These-reduction products~
might be explained by the addition of hydrogen to the alkene
formed from the alcohol.

Tsukervanik (Tzoukerwanik)(15) has preposed a mechanism
of the following type for tertiary alcohols.
t-C5H110H + AlCls—H t-C53110A1012 + 1301
t-CSHHOAlClz ——> 052110 + AlClZOH
C5H10-+ HCl-—-—9t-05H11C1
tfcsfllicl‘t 06H5 ._Al§i3,. t'05311°6£5*t £01
The experimental evidence offered has been the isolation of
alkenes and alkyl halides as byproducts. Tsukervanik sug-
gests that the aluminum alcoholate is formed through the
preliminary addition of aluminum chloride to the alcohol with
the subsequentelimination of H01.
Complex formation of alcohols and aluminum chloride
has been investigated by several workers. Perrier and Pou-
get (21) have proposed two types of solid complexes between
primary alcohols and aluminum chloride. Thefirst, the -
”addition product“ is formed at lower temperatures with an
excess of alcohol. The other, the ”substitution product“,
is formed at higher temperatures with an excess of aluminum

chloride and the elimination of H01

R-o-H R-O- l-Cl
camel 1
01

addition product substitution product‘

This work has been repeated and extended by hpetse (22)

who arrived at the same conclusions. The analytical data
has shown that usually several molecules of alcohol are
associated with one molecule of aluminum chloride.

The ease of formation of an alcoholate would be pre-
dicted to be primary} secondary)>tertiary, since the ease
of replacement of the H of the alcoholic hydroxyl group is
in this order. This is. of course, in the reverse order of
the ease of condensation of alcohols. This criticism is
only valid if it is assumed (1), that the alcoholatc for-
mation is the rate determining step in the overall reaction
and (2), that it is the 0 - h bond which is broken in the
formation of the aluminate. That this. in the case of tert-
iary alcohols, may not be so is illustrated below:

3-0-0 + A1013 —— n~c~o§31l301
H-C-E soc-sh.,IILiL'.Q.IL"=\. '

n n (2)
addition complex

R
(1) HhC-OeAlCl stable aluminate of
hie-H Cl primary or secondary alcohol
H
(2) R Cl
R-C-O Al-Cl unstable aluminate of
h-C tertiary alcohol

The known stability of the complexes of tertiary alcohols
as compared with those of primary alcohols agrees well with
this hypothesis.

The decomposition of prepared aluminates gives varied

products. With primary alcohols the decomposition takes

place at high temperatures giving the chloride. Ethers
also have been reported as forming (22). Aluminates of
tertiary alcohols decompose at room tuperature or slightly
above giving alkones (23).

The addition of H61 to olefins, catalysed by aluminum
chloride is well known. It takes place rapidly even at - -
very low temperatures (24). At this point, all of the sub-
stances necessary for an ordinary Fricde1~Crafts reaction
are present.

Tsukervanik (15) again proposes an aluminate-as the
intermediate in the condensation of secondary alcohols with
. benzene.

.ectROH + LlCl3 -—) ROA1012 + HCl

R0A1012 + 65115 3394-35-1 3-05115 + Houclz
He found no chlorides or alkenes as byproducts. - This mech-
anisn would not explain the rearranged products found by
Kaye.

Tsukervanik (16) proposes the following mechanism for
cyclic alcohols, on the basic of the isolation of the ole-
fins and halides as byproducts, e.g. cyclohexanol‘

c6HnoH + A1013 ——) 061110 + AlClZOH +HC I
06H“, + 11:31 —-> 05111101
C6HlO + c6H6 ——-) 66H1166H5

A101 ,
06H1101 +06H6 ——5—) C6Hllc6H5 + 1101 .

Gustavson (25) has prepared crystalline ternary complexes

at low temperatures, some containing a molecule of H01.

These probably do not enter into thsFriedel-Crafts reaction a“;
sinsethey do not appear to form at higher temperatures.
Several ionic mechanisms have-been suggested.; The‘
three to be discussed all involve a catanoid attack on the :-
benzene ring. Daugherty (26)-suggests_that the active agents
are polarised or ionised_addition compounds between the hale:-
ide and aluminum.chloride and the benzene and aluminum chloride
which exist in small amounts with the ordinary molecules.
cans + A1013: 06H5A1013—g (06H5A1613Y - H“
RX+ A1C13£=PAXA1013¢ R‘i- (M1013)—
(06H5A1013) - H“ +R - (M1013):(CGH5A1013) - R + H - (was)
(06115111015) - R:CGH5RA1013:’ C6H5R+ hm;5
H" - (m1c13);31m1013 :Hx + A1Cl3 .
This theory is supported by the work of Prins (27) which
indicates that benzene ionizes to give phenyl_and hydrogen
ions under the influence of aluminum chloride. pnthe basis
of the above mechanism Daugherty predicted and demonstratedx
’the transference of halogen from one-halide to another, e.g.
the formation of ethylene chlorobromide from ethylene bromp
ids and ethylene chloride under the action of aluminum
chloride.~ . ' ‘ .1 ‘ 7 p
‘h Thomas (28) suggests a proton theory in which the proton
attacks the benzene.
HC1+A1013(_ mm

4
m101“_ H + A1014

H H
+ “C zinc;
H 'l— IIC CH —+E H" CH
EC , . H HC , , ..CI{

. C." + . C .
H H

The hydrogenated benzene is new susceptible to subst--
itution by any compound having an unshared pairs: electrons
(olefin, halide,_alcohol). Addition of the proton-to the;;
alcohol or halide withsubsequent shifting to a more stable
state is proposed to aecount;tor the isomerieation of the -
slkylating agent. This proton theorijill explain the action
of aluminum.chloride in effecting cracking of paraffine,;e
dehydrogenation, isomerization,polymerization and alkylat-
1°n' _ , .. V. . , . . . .. .

The last mechanisn.to be discussed is the catsnoid-theory
proposed by Price (29). ”The reversibility-of the alkylation
of benzene is well knoun. 'Dialkyl benzenes are readily con-
verted to monoalkyl benzenee by refluxing them eith_bensene
and aluminum chloride. ‘Ulich and Heyne (so) have found that
the rate_ot alkylation of benzene_wae directly proportional
to the concentration of the catalyst-aklyl halide complex_
shown below. Wertyporoch (31) has shown that this complex

is ionic.
H i ii c1—-2E H‘ (i ii 01)“
1‘: O. .‘ : d. + .0.- .. .. .0
" Cl Cl
H H

s. C... Rs C."
R"+ no ' on —-v EC ' ' en
:50 .- ‘ ,CH 11c . .3le

'T.‘

:0
. +
O

Alcohols would react analogously. Olefins would associate
‘with aluminumtchloride to give a slightly different tpyc
cation.
1;
R-‘C +AlCl -—-) R-C
II 3 ""‘ |
II—C—H I—E-C—H
+

The sis-trans isomerization of olefins by aluminum.chloride
is easily explained by this type complex '

R-fi-H + A1013 (1" R-C-H“ {— R-g- -H + A1013

R'C’H Re- -H He- OR
013

.The rearrangement of alkyl groups during 31ky18t193,;*
primary to secondary, ect.,~is then due to the electron def-
icient carbon atom in the cation. This is in accordance ;
with theviews expressed by Whitmore in his article on mol-
ecular rearrangements (32)

HH 'HH

CH3 CH3: 01:23 OH—>CH5: g3: d+—-—)013'c~c H
. H} , . .

. -The rearrangements observed by Kaye can be-easily
explained in the above manner. .In the case of boron trig
fluoride as a catalyst, the alkylatipn with alcohols must‘-
be so rapid, in some cases-that isomerisation does not occur.
For_example. d-sec.-butyl alcohol gives small_amounts of 19;.
sec.-butyl benzene in addition to the d,l-eec.~butyl benzene.
The asymmetric alkyl cation must have reacted simultaneously
with.the process of its formation as that racemization was
not complete. The inversion was due to the approach of the
ring at the face of the asymmetric carbon opposite that be-
ing vacated by the anion. 02H5

c2315 - /
\ n -
Q a): - “1:215 Odes
01:3 . . 113

Price has calculated from dipole moments and interatomic

distances the‘charge on thccdlatcm of-various substituent "
groups on the benzene ring. From.these he has calculated
the polarizing force on the double bond of the ring. ~And;
from.this_he obtains_the degree of meta orientation of the
enteringgrcup on the basis of his catenoid theory. ~The
calculated values agree very well with the observed meta
orientationol _ . _ _ _
The formation of olefins and halides, therefore, in -

the condensation of alcohols with benzene is a side reaction.

033 (”13'
R -C-OH +A1013 ——‘ R~C+3+HOA1015

3 R

CH3 CH3 CH 1 f
H-Ici+?"—<_=%+01<__rR-§-01 and mm 53% R- c = 0112

In an earlier article Price_(33) has shown that with
333 as a catalyst, the conditions for the alkylation ef-j
naphthalene nith cycloheranol are_nnch less vigorous than:
those for the formation of cyclohexene from.the alcohol by
the action of 3-3. .

. In summary, and mechanism to be considered should be
consistent with the observations made by Huston and oo-wcrkers
that condensation is aided greatly by strain on thenoccarbon
atom of the entering group.' In the case of saturated alie
phatic alcohols the amount of strain is in direct relation-
ship with the case of dehydration.‘ Koweyer, in considering
other types of alcohols, it becomes apparent that some
condense readily which cannot-dehydrate-easily, e.g.3benzyl

alcohol, benzhydrol, and cyclybutyl carbinol. The relation-

n 1,- 5.1!, 31.1.! 4
A

ship of this strain to the formation of carbonium
in not well established.

ions

‘4 .-__.

M
ch

Preparation of Dimethyl Tert.-butyl Carbinol.

Butlerou first reported the synthesis of dinethyl
tert.-bptyl carbinol in 1875 (54). He prepared it by the
laborious reaction of zinc dimethyl on trimethyl acetyl
chloride. He noted the striking property of the ease of
formation of a solid hydrate and showed by analysis that
it contained two molecules of carbinol per molecule or
water. He prepared the corresponding chloride, iodide,
and alkene from the alcohol by the usual methods.

The cerbinol was prepared in 1881, with difficulty,
by the action of zinc dimothyl on the acid chloride of
trichlor-scetic acid (35). In the same year it was pre-
pared by Kaschirsky from oCbromo isobutyryl brorfide and
zinc d1methy1.(36)

Henry (37) isolated the carbinol as the main product
in the attempt to make the monochlorhydrin of pinscol
by the action of methyl magnesium.bromide on ethyl
chloro~isobutyrate. Henry suggested that the carbinol

was formed in the following manner (38):

(CH ) .. - -oc ,.+CH --Br-—)(CH)- .. -CH
3221 8.1311" 3mg 3231 high:-

 

Jim, (035)2-c -fc (CH3)2 Cfingg ((315)343 .. 8.251%?)2

Henry (39) prepared the intermediates by separate

synthesis and showed that both were converted into the

f‘ n
0.; .7}

carbinol on treatnent with crsrgnr. He also preparedthc

carbincl from acetone and tert.-butyl magnesium chloride
(40).. he obtained very good yields of the carbinol by the
action of meth¢1_megnesium‘bromide on pinacolone (41),

Several other nethods, very similiar to the above,
have been described.

All of the above mentioned workers have described the
peculiar ease with.which the carbinol combines with*waterM
to form a solid hydrate.. Edgar (42) and Whitmore (43) have
also described this property.

nhile_acverel other aliphatic alcohols form hydrates
(tert.-butyl, isepropyl, eat.) the melting point of the
hydrate in all cases, is lower than that-of the pure alcohol.
Dry dimetnyl tert.-butyl carbirol forms a hydrate instantly
on contact with meter or even moist air, which has a.melting
point eistyufive degrees higher than-the carbinol.iteelfe;
In this laboratory, all of the possible tert,-;emy1,-hexyl,
heptyl and octyl and some of the higher secondary alcohols
have been prepared. All are liquids at room temperature  
and with the above exception none form solid hydrates (none.
has been reported an forming a liquid hydrate), -Thie unique
case of the formation of a white crystalline hydrate by
dimethyl tert.~butyl carbirol.glgg§ has not been satisfact-
orily explained.

Dutlerow and.3dgar reported that the hydrated'water

could be removed by allowing the crystals to stand over

ill 5-2.! 1.44

U)
a)

barium oxide. This worker, however, found that the anhy-
drous form was not obtained by this method even after
standing a dessicator over barium oxide for sever 1 months.
The alcohol was readily dried by allowing an ether sol-
ution to stand several days in the presence of metallic
sodium, the latter at reduced pressure.

The carbinol, itself, melts at 17 and boils at 128-
30. It has a camphor-like odor characteristic of the
tertiary heptyl and octyl alcohols. The hydrate melts
at 80 sublimes readily at roam temperature, and distills.
over as the solid at about 120-5.

Edgar (42) and Whitmore (43) have prepared the car—
binol by the action or tert.-butyl magnesium.chloride on
specially purified acetone. In this laboratory Binder
(44) prepared the carbinol by the procedure of Whitmore
obtaining yields 0 f 15-80 w. Hedrick (45) also in this
laboratory prepared the carbinol from pinacolone and
methyl magnesium bromide obtaining 70 % yields based on
the pinacolone. '

Several methods were used by this worker. The prep-
aration from pinacolone proved to be the most successful.
Pinacolone was prepared by the reduction of acetone with
magnesium and rearrangement of the resulting pinacol by
means of the procedure given in Organic Synthesis (46).

The carbinol was also prepared by the actibn oi two
moles of methyl magnesium bromide on trimethyl acetyl-

chloridc. The latter was prepared from the acid by

 

nu. «+15%le

-v.—.-.

means of thionyl chloride. Trimethyl acetic acid wcs
prepared from tert.-butyl magnesium chloride and carbon
dioxide.

Another method of preparation was again by use of
methyl magnesium bromide, this time five moles reacting
with one mole of the ethyl ester of tricholo-acetic acid.
ihe ester was prepared from the acid chloride, the latter
being prepared from the acid by means of phosphorous

pentachloride.

Preparation of Pinacolone

Pinacol hydrate was prepared from acetone and mag-
nesium by the procedure civen in Organic Synthesis (46).
The pinaeol hydrate wis converted into pinacolone by dis-
tilling from.6 N sulfuric acid (Org. Syn.). The pinacolone
was dried and fractionated. The fraction boiling at 103-?
was collected. Yields, based on magnesium, are from

30-35 %. In all about 1800 grams (20 runs) were prepared.

Preparation of Methyl magnesium Bromide

The Grignard reagent was made by passing gaBOOus
methyl bromide into magnesium turnings suspended in ether
in a three—necked flask fitted with a reflux condenser,
motor stirrer, and inlet tube for the gas. Enough methyl
bromide for five moles of Grignard reagent was generated

by heating (sand bath) 320 g methyl alcohol, 750 g cone.

“I -4.

sulfuric acid, 50 cc water, and 1050 g sodium.bromide
in a three liter round-bottomed flask. The methyl
bromide was passed through a wash train consisting of
three bottles of 40 %JNaOfl and three bottles of cone.
sulfuric acid with three saftey bottles. Five and one
half moles of magmesium.and three liters of anhydrous
ether were used in a five liter three necked flask.

The methyl bromide was passed in until the magnesium had

all disappeared.

Reaction of’methyl Grignard Reagent.

The pinacolone, or trimethyl acetyl chloride (see
below),‘was slowly dropped in, substituting the inlet
tube with a dropping funnel, and the mixture stirred
for several hours after the carbonyl compound had been‘
added. Sometimes, it was necessary to add more anhydrous
ether.

The mixture was hydrolized on ice and enough hydro-
chloric acid to dissolve the magnesium.hydroxide. The
ether layer was separated and the water layer extracted
five or six times,'with ether, to remove the hydrate,
which is fairly soluble in water. The ether extracts
were washed with water and dried first with anhydrous
sodium sulfate and then with metallic sodium.for several
days. The alcohol was distilled from the sodium under
reduced pressure, the fraction boiling at 48-51 (20 mm)

was collected. About ten moles of carbinol were prepared

33

from Pin80010ne by this method, the yields being 70-75 %.

Preparation of Terethyl Acetyl Chloride.

Tert.~butyl magnesium chloride was prepared accord-
ing to the excellent procedure given by Uhitnore (43 .
Details will not be given here.

Carbon dioxide was passed into 2.5 moles of the
Grignard reaeent accordina to the directions given in
Organic Synthesis (4'7). Trimethyl acetic acid G3 P 164,
‘ H.P 35) was obtained in 53 % yield.

The acid chloride was obtained by addina 60 g thi-
onyl chloride to the acid in a 250 cc Vigereux column.
lhe mixture was slowly distilled, flCl, 602 and excess
thionyl chloride coming off first. The acid chloride was

collected at 116, 80 g were obtained (69 % yield).

Preparation of Ethy Ester of Trichlor-Acetic Acid.

One hundred and eighty grams of P015 were slowly
added to 200 g trichlor~acetic acid (commercial product)
in a 500 cc Vinereux column. The acid chloride, alone
with some phosphorous oxychloride were slowly distilled
off (B P 115-20). The distillate was immediately placed
in a 500 cc round-bottomed flask fitted with a reflux
condenser. To the mixture was added 100 cc absolute
ethyl alcohol with cooling. The mixture was then refluxed
for two hours until the evolution of hCl ceased. The
ester was then distilled (BtP 168) and 170 g were obtained.

The percent yield of ester, based on the acid was 73 b.

34

15.3 ester was added dropwise with stirring: to five .
moles of methyl mrlpniesium bromide, prepared as above.
When the reaction had subsided the ether had evaporated
off and two liters of anhydrous toluene added. The mix-
ture was refluxed for eight hours and allowed to stand
over night. It was then hydrolized, extracted, dried,
and distilled in the manner described above. Twenty-three

g of alcohol were obtained (20 $5 yield).

55

LAPLRILEKTAL

Several preliminary oondensations were run to deter-
mine the conditions and amount of A1015 to be used. jThe‘
following procedure was used with slight modifications for
all condensationa.

The reaction was carried out_in n three-necked flask
fitted with a mechanical. glycerine stirrer, a reflux cond-
enser and a dropping funnel. Thiophene free benzene,_dried
over sodium.was used. The aluminum chloride was Baker's Q
C. P. anhydrous resublimed. The aluminum chloride was added
to the benzene, the mixture stirred for two or three hours,
and the alcohol slowly added dropwise with stirring.-;After
all the alcohol was added the mixture was stirred several-
hours more and then allowed to stand-overnight. The mixture,
was hydrolized on ice and small amounts of hydrochloric acid.
The benzene layer was separated and the water layer extracted
several times with ether. The combined layers were washed
with dilute sodium carbonate and then dried with anhydrous
sodium.sulfate. The ether and benzene were-distilled off
and the residue fractionated under reduced pressure. 'For
the first five condensations a Vigereux column was used. -
Thc products of the remaining condensatione were fractionated

with the spinning band column.

to
O}

Condensation I

Alcohol % mole (51 a;
A1313 i/e ' 44 g
Benzene 2% “ 270 cc)

The hydrated form of the carbinol was used. Slightly
larger amounts of A1013 were used to take up the water. The
alcohol was dissolved in half of the benzene and the eolution
added dropriae to the mixture. The reaction temperature was

0. Only small amounts of product were formed.

finndeunniicn 11
Alcohol 1 mole (125 .)
A101 % ' 70 a?
Benzene 5 I 390 E)

The anhydrous alcohol was added to the mixture of ben-
zene and aluminum.chloride. The reaction temperature was 0.
The following fractions were obtained. The'weighte listed
are not to be taken as those of pure fractions since no

precise separation could be made.

1 48-51 2“ mm - 25 g
2 (SC-71 20 mm '- 1 g
3 71-74 20 ran - 4 g
4 75-104 2~ mm - 3 g
5 104-109 SC- mm - 23:: g
6 115-130 20 mm - 5 g
7 above 130 20 mm. - 4 3

Fraction 1 consisted mostly of the alcohol, as solid hydrate.
Fraction 3 was id ntified as tert.-butyl benzene.’

Condensation III

Alcohol 1 mole 115 .)
A1C13 % ” 68 3%
Benzene 5 ' (390 g)

The anhydrous alcohol was used. The temperature was

40-45. The reaction mixture turned very dark. ‘The follow-
ing fractions_were obtained. Again the separations are not
very accurate.

43-55 20 mm

1 - 7 g
2 55-70 20 mm - 2 g
3 70-78 20 mm - 6 g
4 78-83 20 mm #- 1 8
5 83-93' 20 mm - 1 8
6 93-102 20 mm - 2 g
7 102-108 20 mm - 20 g
8 108-150' 20 mm - 7 g
9 108-155 ‘ 11 mm - 4 g
10 above 155 11 mm - 6 g

Fraction 1 consisted mostly of the alcohol, Fractions 5 and 7

were identified as tert.-butyl and tert.-heptyl benzenes, res-

pcctively.*

Gondcnaaiinn IV
Alcohol 1 mole (130 g
A1C13 1 ” 133 g
Benzene 5 ” 390 g

The reaction temperature was 10-15. The mixture turned

very dark. The fractiona~werez

p
O .

43-50 20 mm

1 - ‘ a
2 50-62 20 mm - 3 3
5 64-70 20 mm - 12.8
4 70-78 20 mm - 4 3
5 78-83 20 an - 2 E
6 83-93 20 mm - 1 g
7 95-102 20 mm - -7 8
8 105-107 20 mm - 8 g
9 107-111 20 mm - 11 g
10 111-150 20 mm - 6 g
11 108-140 11 mm - 9 s
12 above 140 11 mm - 4 g '

Fractions 5 and 4 were identified as tert.-buty1 benzene.

Fraction 8 was identified as tert.-hepty1 benzene.

37

 

 

 

 

 

 

‘ Table III fl
Condensation recovered t.-butyl intermediate t.-hentyl >
alcohol benzene Eel. Wt. 150 benzene
I 3055 1:6 1;: 1
II 20» 4'26 222$ 14
III 5» 5:5 4214 '12
IV 7% 8:3 7;; 6

 

 

 

 

 

 

From the results above it can be seen that the hydrated
fern.o£ the alcdhol is not very active in condensations.
Low temperatures give relatively higher amount. of the tert.-
heptylbenzene while higher temperatures give more of thc‘
lower alkyl benzenes and also more of the very high boiling
compounds. Larger-quantities-or aluminum chloride at about
room temperatures appear to have little efcet on the products.

Accordingly a larger amount of the alcohol was con--»
densed atle-lfi using one mole of alcohol per half mole of

aluminum.chloride.

WV
Alcohol 4 moles 460 g
A1013 2 " 264 g
Benzene ‘ 20 1' A.- 1500 cc).

The reaction temperature was 10-15. _An 18 inch Viger-
eux column was used for the first fractionation.t Large~-
quantities of HCl were given off during the first part of :-
the distillation. The fractions below were subject to care-
ful refractionation using the special column built for this

purpose.

80-110 760 mm

‘ 1 - 88 g éHCl off
2 110-130 760 mm - 93g "Cl off
3 50-64 20 mm - 9 g
4 64-69 20 mm - 17 a
5 69-83 20 mm - 32 g
6 83-93 20 mm - 7 g
7 93-102 20 mm. - 40 g
8 103-106 20 mm - 14 g
9 106-111 20 mm - 45 g

10 111-130 20 mm - ‘ 6 g
11 121-180 S’mm - 60 g
12 above 180 8 mm - 3 g

Fractions 1, 2, and 3 consisted of a mixture of ben-.:
sens, the solid hydrate and other compounds. -Ihis mixture
could not be fractionated with the spinning band column‘
because of the solids. Accordingly a vacuum.3acketed 20-
inch Vigereux column with a large bore sidearm (10 mm)'vas
used. An ordinary Wurtz flask nae used as a reciever.‘-It
‘was cooled with a stream of water. By this_nethod of free-
tionation three compounds were isolated. ~0ne, boiling at
70-74 was identified as 2,3,3-trimethyl butane-1. Another
was the tnnzene. boiling at 80-82. . The third, boiling at
110-130 was the solid hydrate of the alcohol.- The hydrated
toms of the alcohol, even when carefully purified, does not
boil sharply, small crystals first appearing on the sides
of the reciever at about 110. The majority of this third‘
fraction boiled at 124-128. Small amounts of chloride were
found mixed with it.

Fractions 4, 5, and 6 were fractionated under reduced

pressure with the spinning band column. Small amounts of

40

the lower boiling compounds, above, were found. The greatest
portion boiled constantly at 52-52.5.(11 mm), This portionf.
was identified as tert.-butyl benzene. The residue was mixed
‘with fractions 7, 8, and 9.

The separation of the-compounds mixed in 7, 8, and 9 ;;
was accomplished only by carefull adJustment of the different
variables of the column. With the column set at total reflux,
the temperature of the heater for the still_pot use adjusted
so as to allow very gentle reflux. The Jacket temperature
was adjusted to the temperature of the~refluxing-vapor(1ns-
chutz readings). Too slow refluxing caused the vapor_temp-
erature to fluctuate and be markedly low. Too-rapid reflux-~
ing again caused too low temperature readings and also-caused
slugs of liquid to pass up and down the column._ The large
volume of vapor rising into the reflux condenser gave rise
to appreciable amounts of cold liquid which were returned
to the column. This relatively cold liquid lowered thev
temperature readings and, in addition, condensed more of the
vapor - which is at equilibrium temperature. This formed
a mass of liquid in the upper portion of the column com-
pletely upsetting the equilibrium conditions.

After the lowest, constant, temperature readings, with
refluxing, were obtained, the stopcock a was partially opened
to allow the distillate to collect. The reflux ratio was
set at about 10:1 or 15:1. If the temperature varied more-
than one-half degree, the stopcock was closed and the column

'was operated at reflux until the temperature came back to

41

normal. The distillate was then collected as before.

When most of the lower boiling compound had been removed
the temperature readings were not constant. For example,
in the separation of tert.-buty1 benzene from the next higher
boiling compound, tert.-amyl benzene (B. P. 69 -;11 mm), when
only small amounts of tert.-buty1 benzene were left the temp-
erature sould drop. The heat input at the bottom of the col-
umn, uhich.was Just sufficient to drive the tert.-hutyl ben-
zene vapor to the head of the column, was not quite suf— I
ficient to drive the tert.-amy1_benzene vapor to the head
in sufficient quantities to give accurate temperature read-
ings. This difficulty was remediedby increasing slightly
the heat input at the bottom.of the column.

_As the amount of tert.-butyl benzene in the vapor bee
some very small the temperature readings rose rapidly.: She
column was then operated_at total reflux until the temper?
ature readings dropped to the‘boiling-point of tert.rbutyl;
benzene (55 a 11 mm). The stopcock was then opened and dis-
tillate collected, at a high reflux ratio, until the readings
again rose. By using this procedure repeatedly a rather
precise separation could be made. Only a few drops‘were.
collected between the boiling ranges of tert.-butyl and tort.-
amyl bensenes.

The tert.-amyl benzene was separated from the higher
boiling compounds by this same-prooedure.~

The separation of highly boiling compounds by fraction-

ation under reduced pressure hacomes more difficult as the

42

boiling point increases. With~ths above compounds the
boiling points of the pure compounds under reduced pressure
were very simply determined. However, the distillation of
fractions 7, 8 and 9 gave no sharp boiling temperatures,'
ranging from 75 to 95 (ll mm) depending upon the_oonditions
of distillation. These variations in vapor temperatures
were due to; first, the inherent difficulties found in;;
fractionating high boiling compounds and; second, the fact
that three or more rather closely boiling compounds were
present in the vapor.

The boiling point of the first was known, 69 (11 mm) -
the tert.-amyl benzene. .The highest boiling compound W33;
the tert.-hepty1 benzene. Its boiling range was approximately
known, 10:5. (12 mm).

The boiling point of the compound comprising the middle
portion of this fraction was,_of course, unknown. For a .
good separation it was, however,necessary to know its boil-
ing point.

This intermediate compound showed-positive tests for
unsaturation. A series of fractions of this intermediate-.
compound differing in boiling point by about one degree were
out. Micro-iodine numbers were run on each. -The fraction
having the highest iodine number was assumed-to have the----
boiling point of the pure unsaturated-compound.~ The results
are shown in the graph-below.“ They indicate that 81 (11 mm)
is the boiling point of this compound.

43

iodine J

/\

 

 

79 80 81 82 83 B. P. 11 mm

Continued fractionation gave a fairly large portion
boiling at 80~83 (11 mm). ~This unsaturated fraction prob-
ably still contained some amounts of tert.-amyl and tert.r;
heptyl benzene. however, it was sufficiently pure for iden-
tification. .

Since relatively largeamounts of tert.-heptyl benzene
were formed its boiling point was readily determined. ‘The
separation of the tert.bheptyl benzene pas attended with no.
special difficulties. ‘Its boiling range was 103-106o(llmm).

.The rather large amount of material boiling above-the;
tert.-hepty1 benzene was not redistilled. The distillation
with the Vigereux column had indicated no sharp fractions,
the temperature readings rising steadily as‘t c distillation

proceeded.

Wflmt one-
The fractionation of the lower boiling portions of-;

later condensations has shown the existence-of three more-;
byproducts in addition to-those mentioned-above.- The proof

of structure of these compounds will be discussed here.

129212211 thgride. The identification of this com-

pound is based on the following facts:

Eoilin oint * . ; ‘
Y0 sérgng Beilstein test 55 6
mei¥in6 Paint of the anilide 107-8

44

The only possible halogen present is chloride. The isopropyl
chloride was mixed with the ether (used in the extraction}
frmn'vhich it is very difficult to separate. The difference
in boiling point is two degrees. The spinning band column
was used to obtain the chloride in sufficient concentration
so that identification was possible. The anilidc was made
by the procedure given in Shriner and Pusan (48) except that

no more other was needed as a solvent.

.2a§a§:IIIE££BEleHL2£§:lp This compound was idegtified
by passing in dry 5C1 which converted it to the chloride of
dimethyl tert.~butyl carbinol. This chloride has a charact-

eristic odor and melting point.

Boiling point 77-8 '
halting point of derivative 125-7
'relting point of known 126-7
Kixed melting point 124-?

Details for the preparation of the known are given on page
The phenomenon observed during the distillation of this
portion of the condensation products would indicate that
this unsaturated compound had arisen from.thc chloride.
During the distillation of the be nzene (used in excess in
the condensation) no $01 is given off. When the boiling
point reaches about 82, instead of rising fur her, it suddenly
drops to about 67. During the collection of this portion.
of the distillate the temperature ranges between 67 and 70
and large quantities of 331 are evolved. This portion, when
washed with dilute sodium carbonate solution. dried and dis-

tilled. boils at 770. These facts are interpreted to mean

45

that after the benzene is removed, the chloride - the next
higher boiling compound - is decomposing and coming over as
the slkene and HCl, the mixture of which boils lower than
the alkene alone.

W W. This compound was
identified by means of its melting point, 125—3. Only.
small amounts are left from.the distillation at stmospheric
pressure, above. The solid chloride and the hydrate of;
the alcohol distill over together.- The mixture can be sep-
arated by recrystallization from warm 70 fi alcohol. The

chloride sublimee very readily.

Zaxig:;nixllfignz2a§. This compound was identified by

its acetamino derivative. “
Boiling point . ~ 165-6 gmi- mm)
. 54 (11
Helting point of derivative 169-70
helting point of known . 169-70
Mixed.melting point 169-70

The acetamdno derivatives were also used for the identifi-:
cation of the other alkyl benzenes_found as byproducts.~ The
method used for their. preparation was that given by Ipstieff
and Schmerling (49) with slight noditicetions.
The nitro compound was prepared‘byosrefully treating

3-5 cc of the alkyl benzene with 5-lO-cc of a-ltl mixture----
of concentrated sulfuric and nitric acids. -When the reaction
mixture had cooled down it was poured onto cracked ice and»-

extracted several times with ether. The extracts were washed

3b
a)

'with water and the other evaporated,

The nitro compound was dissolved in a few cc of alcohol
and 5 grams mosey tin added. About 5 cc concentrated nel-
‘wac added dropwise,_with shaking. The reaction mixture was
allowed to stand 25-30 minutes. The liquid was decanted on,
to water and the tin hydrochloride complex salt of-the amine
extracted with ether.- The other was evaporated Off and 50 %
sodium.hydroxide was added to free the amine. Vith_larger‘
amounts the amine vac steam distilled at-thie point. :0ther71
'wiec it was extracted with ether. -It was eometimee necessary
to centrifuge to break the emulsions of ether and sodium :
hrdroxide solution. The ether extracts were washed and dried
with potassium carbonate‘~‘l

After the ether vac evaporated off the acetyl derivative
was made by adding two cc of acetic anhydride to the amino;
compound. The exceee anhydride was then‘hydroliaed.by'warnp
ing with 30 cc water. The solution was then cooled and the
impure solid filtered off and washed free of acetic acid.

It was then recrystallized from 30-50 % alcohol.

W Jame. This eonpound was identified by

means of its acetamino derivative.

Boiling point - -- -- 190 (740 mm)
" 79-80 (11 mm)

Eelting point of derivative 137-8

Melting point of known 138-9

hired melting point - - 137-9

Tert.-amyl benzene was synthesized by condensing tert.-amyl

chloride with.benzene in the presence of aluminum chloride.

47

About 80 % yields were obtained. .Ihe acetanino derivatives

‘vere prepared by the method described above.

{Iriscthxl.fltxzene. The identification was made-by scans
of the acetamino derivative of the hydrogenated compound.

Boiling point ' ‘ 88-90 (11 mm)
Kelting point of derivative 159-40
Lelting point of known 140-41
-Kixed melting point - '139~41_H

The oxidation of the unsaturated alkyl benzene gives
acetophenone, identified by its_semioarbazone.

Boiling point (oxidized product) 200-215
Iolting point of eemicarbazone 192-4
Eelting point of known 193-4
Mixed.melting point -192-4

The semicarbazone has made by the procedure given in Shriner
and Fuson (50). .It was purified-only with repeated recrys-
tsllisation. The fact that oxidation gave acetophenone
very strongly indicated that the unsaturation was on the
carbon of the alky1.benzene.-~ , ‘ __‘
Trimcthyl styrene vas made by Grignard synthesis. rhenyl
magnesium.bromide was treated with methyl,ieopropyl ketcne
to give, on hydrolysis, methyl,isopropyl.phenyl carbinol.
This alcohol was distilled from anhydrous oxalic acid to
form the alkenc,‘13. 1575-8 .(12. mm.)..T
Another unsaturated alkyl. benzene-which night‘torm- in-
the condensation, and which gives acetophenone-on oxidation:~
is octert.-butyl styrene (51).»~This compound nae synthesized
in a manner similiar to that above except that pinacolone

was used as the ketone, B. P. 88-92 (15 mm )

The two above known_compounds along vith_the unknown
fraction sere hydrogenated-using the procedurcgiven by;---
Kaye (13). The resulting alkyl benzenes (secondary isoamyl
benzene, pinacolyl benzene and the unknown) were converted
to the acetamino derivatives. The derivative of pinacolvl
benzene came down as an oil. the other two as crystalline
Plateao. .

Procedures

Onehalf mole bromsbensene was added dropwiee to 12 3
magnesium turnings in 200 cc anhydrous ether in a three-
necked flask. The reaction mixture wasstirred and the halide
added at such a rats as to reflux the mixture gently. The‘
was added slowly to the Grignard reagent with stirring. The
mixture'vas hydrolized, extracted and dried in the usual man-
ner. The ether was distilled off and the carbinol placed
in a small Vigereux.column. asboutrlo g anhydrous oxalic.;
acid was added and the-mixture distilled under-reduced pres-
sure. The alkene was then redistilled. The yields were
'20-30 :23. . ‘ _ _

p The alkenes were dissolved in do cc absolute ethyl 1~
alcohol and pieces of sodium added at intervals... About: 12
grams was used .for. each. . The mixture-was kept at gentle
reflux for five hours. -The alcohol solutions were~then a.
poured on a large volume of.water-and-extracted-several times
with other. The ether extracts sore washed free of alcohol
‘sith concentrated CaClg solution. -The ether-was then evap-

orated of! and the resulting product shaken with cold

49

saturated.hhn04 solution to remove the unredueed alhenes.
The excess Khho4 was destroyed with sodium.bieulfite andg
the mixture again ether extracted.. After the ether has~been
extracted the resulting alkyl benzenes were used-without
further purification for the preparation of the acetamino
derivatives.

The acetamino derivative of the unknown was purified
only with great difficulty. v . _ . .

The range in atmospheric boiling point (190-9) and the
necessity for repeated recrystallization show the lack of
purity of this fraction. The atmospheric boiling points
recorded in Beilstein's handbook are only slightly above
those given for tert.9emyl benzene. 'Any fraction conteining
the former compound.must also contain sons of_the'latter.-
The tert.-amy1 benzene fraction fraction, however. did not
show a positive-test for_unssturation.e--

The fact tLat the unsaturated fraction boils much-higher
then the tert.~anyl benzene fraction-(st reduced pressure)
certainly indicates that it must.contsin-compounds boiling
higher than trimethyl styrene. This again indicates the
presence of another unsaturated compound e.g.1$:tert.—butyl
styrene. This compound which has raised the boiling point
of the trhmethyl styrene fraction must also be unsaturated,
it cannot be the tert.eheptyl benzene alone,-since the-boil-
ing point was determined by determining the maximum unsatur-

ation.

50

‘2.§.§.:2:£m£3311.22h£nx1‘Bntang.. Thisis the expected
condensation product of the alcohol and benzene. vIt has
identified by means of its nitro compound which has been
previously prepared by Rodrick (45). Of the pure parasg:
nitro alkyl benzencs which have been prepared in this lab?
oratory, which includes all of the tert.éaliphaticbenzenes
up to the octyl group, this is the only one that is solid
at room temperature.

Boiling point ' I 103-5 (12 mm; 220-5
halting point of_derivative ; '108 ; , .

This compound has only been syntheeided by Friodel-
Crafts or related reactions. However, dimethyl tert.e-
butyl carbinol. its chloride and its unsaturated derivative
all gave this same product. This alkyl_benzene converted
to the p-hydroxy compound is identical nith the compound
obtained by the condensation of the above carbinol with N
phenol. These facts leave little doubt as to its identity.

. Thr reaction characteristics of a typical condensation
are described below. The temperature of the condensation
has a marked effect.

Aluminum.chloride in benzene has-a pale yellow-color.
if refluxed or allowed to stand several-daye-it-becomes
darker yellow. The addition of the alcohol immediately gives
a orange compound. During the-addition of-the first-half
of the alcohol (ratio of alcohol to aluminum chloride-is ,
2:1).Hgl is given off and more of this colored compound 19‘.
formed. This compound at ~10 is solid and becomes-dark red.
At 25-30 it is liquid and is also dark red, three layers are

therefore present: benzene, unreacted aluminum chloride, and

51

the above compound.

During the addition of the second half of_the alcohol
at ~10 there is no more HCl evolved, and.more of the~tarry;.
red solid forms, making stirring difficult. Petroleum ether
is added_to keep the benzene from freezing. .At 39-40 HCl
is evolved throughout the addition of the alcohol. ‘At the
end of the condensation (at 55) two layers-are present.-the.

lower layer having formed at the expense of the A1013 layer.

‘Qiecussion..

The reaction characteristics agree sell uith the mech-
anism.prcposed.by Tsukervanik. The large quantities of HCl
evolved during the addition of the first half of the alcohol
‘would be due to the formation of the alcoholatc which is ,
stable at -10. During the addition of the last half of the
alcohol, the alcoholate, for some reason; is broken down and
the resulting alkene takes up the H61 as fast as-it is formed
by the addition of morealcohol. Therefore, at low temper-
atures, no 301 is evolved during the latter portion of the
reaction. At higher temperatures, the alcoholate is decomposed
as soon as it is formed,-the series of reactions proceeding
to the formation of the alkyl benzene and, consequently H01
is liberated throughout the addition of the alcohol. .

The Tsukorvanik mechanism, of course, does not explain
the mechanism.of the actual formation of the alkyl benzene
from.the halide.

52

 

m1. - I’Aiil‘ II

Some further condensations_wcre run to investigate
the possibilities of the Tankervanik mechanism and to attempt
to explain the origin of the byproducts formed..

The alcohol was condensed et-~lO and at 40. The alkene
formed by the dehydration of the alcohol was condensed with
and without the presence of large quantities of £01.. The
chloride of the alcohol was also condensed.l Some aluminumf
chloride complexes oftert.-butyl alcohol were also invest-

igated. The results of these condensations are listed below.

gondensation V1

Alcohol % mole (58 g
A1013 5 i ~ " (33 g
Benzene 1* " (80 5
Temperature ~10

Pet. ether~ .- 65 g-

The reaction flask and contents were weighed.beforez
and after the condensation. The loss in weight was ll 3.-
About .15 moles no; (5.53) were evolvedeuring thereaction.
Another gas was given off which decolorized 5 fi'bromine in
carbon tetrachlroide. ’ . . _

A dark red, tarry mass formed in the flask.» The liquid
and solid portions of the condensation products were hydrol-

izcd and distilled separately.

53

The liquid portion gave:
35-40 740 mm

1 - 5 g
2 60-80 740 mm - 60 g
3 125-50 740 mm - .5 g
4 above 130 740 mm - 7 g
740 mm

The solid portion gave:
5 55-43 740 mm - 5 g
6 67-70 740 mm - 2.5 g
7 125-30 740 mm - lgvg

The higher boiling portions were combined and fractionation

 

gave:
8 51 ' 11 mm - 2 g
9 69 11 mm - l g
10 88-93 ‘ 11 mm - 4 g
11 98-103 11 mm - 10 g
12 above 103 11 mm - 7 g
Condensation VII
Alcohol i mole (59 Q2
A1C13 ' g “ (35 as
Benzene 1 " (79 3
Temperature 40

The reaction flask and contents were weighed before
and after condensation. The loss in weight was lfl_g. Again
a gas that decolorized bromine was evolved. At the end_of
the reaction two layers were apparent. Hydrolysis and frac-

tionation gave:

55-40 740 mm

1 - 10 g'
2 - 740 mm - 16 g
3 igozgo 740 mm' ‘ 8 5‘
4 53 11 mm 0 2 g
6 88-91 ~ 11 mm - 1. 5 g
7 98-103 11 mm - 8 g
8 above 105 11 mm ' 10 g

54

Condensation VIII

 

Alkene é mole (39 g
A1C13 g " $34 g
Benzene 1 ” 80 g
Temperature 25-50-

2,3,5-trimethyl butene-l was prepared by the method
used by Edgar (42). Fifty-five g of the alcohol and lgg
iodine were placed in a Vigereux column and the mixture
distilled slowly, the temperature of the vapor being maintained
at 68-70. The distillate was washed wit Ea23205 solution,
water, and dried over CaClg. The product was distilled, the
maJor portion coming over 77-79. Yield - 39 g (80 fl . The

fractions obtained from the condensation.

 

1 155-40 740 mm - 5 g ..

2 53 11 ms; - n g

4 80 11 mm - 2 .5:

5 94-97 - 11 mm - 1 g

6 100-103 11 mm - 2.5 g x

7 above 103 - 5 g
Condensation IX

Alkene l/S mole 54 g

A1013 1/6 “ 34 g

Benzene 8/3 " (52 g

301 31; "

Temperature 25-50

The alkene was prepared as above. The dry hydr0gen
chloride was made from sulfuric acid and hydrochloric acid

and was passed in slowly throughout the addition of the

alkene.
1 5-40 740 mm - ‘5 g‘V
2 53 -- 11 pm - .5 g
3 69' ‘- 11mm - .15-g.—
4 87-90 -- 11 mm - ; l g
5 100-103 11 mm - 2.5 3*
6 above 103 ,11 mm - 8 g

55

Condensation 2i

Chloride 2'; mole (50 g
A101 1/6 " (23 g
Benzgne l “v ’ (80 g
Temperature 25-30

2,3.3-trimethyl,2-ohloro butane was prepare-:1 from the
alcohol by treating with thionyl chloride and distilling.
It was also prepared by passing dry 1101 into the alkene.
The chloride prepared by each method was a solid. It was
dissolved in half the benzene for this condensation. The

fractions were:

1 35-40 74C m - 5 S a
2 5:5 11 mm - .5 g
3 90-92 11 m - 4.5 5
4 100-103 11 em - 7 g

5 above 103 11 mm - 5 g

Condensation XI

 

Tert.-heptyl benzene 3 mole 42 g
.uc13 e a 15 g
Benzene l ' 80 g

 

Temperature 25
The tert.-hepty1 benzene obtained from previous con-
densations was added in the usual manner to the benzene and

aluminum chloride: The mixture turned dark. The fractions

were:
1 35-40 740 mm - 5 a
2 48-50 11 mm - 1 g;
A: 100-103 11 mm - 54 g;
c" above 163 11 ms: 3 g

Condensation‘XII
Complex of tert.-butyl

alcohol and A1013 3 g
Benzene go 6
Temperature 25-30

Both the addition and the substitution complexes as
reported by Ferrier and Fouget (21) were prepared. Lech
was mixed with benzene and stirred several hours. A dark
red terry mane formed, in each once, which on hydrolysis
gave high boiling aliphatic comp undo. T40 substitfition
complex was eloo added to benzene while passing in SCI.
However. in no case was there any tert.-butyl benzene found
as a product.

The addition complex was prenorod by adding 24 g A1013
slowly to 30 g tert.-butyl alcohol in 100 cc 033. Little
HCl woe evolved. A red tarry mane separated and the carbon
dieulfide was decanted off and file conrlex dried in a vacuum
desiccator. It was then ground to a rod powder.

The substitution comnlcx one prepared in tEe some manner
except that 38 ; A1015 were used for 20 g alcohol and the

mixture refluxed. Large quantities of 131 were given off.

The results of theoe condensetionn are summarized in
taLle 1V3 It muot be kept in mind that the results are
quantitative in only a rough sense. TEe per cent yieldo are
calculated on the assumption that one mole alcohol theoret-
ically forms one mole of tbo nroduct. to figures are given
for ieogropyl chlorid and 2.3,3-triwetlyl butane-l since

' ~ ,. ., ._,_... .- 1 A,
these compounds boil so near to ether and bonscre. ron,ective43.

57

there the alkene 13 liated 33 being formed it may be taken
that 2,3,3-trigcthy1 2-chloro butane was also formed.

The per cent 116169 of tert.-butyl bnnzene and tart.-
Legtyl bcrzcne are lower than £30 values reported in the
preliminary ccnaahsgtiona &ue to the fact tLat more of these

substance: are lost during he fractionation.

58

OH
m.“

I!)

OH

vow%wu
acwvflad

AEEHHV
NOH m>opw

Hopocmm

HhuSDI.» Spay

Ilct III! unis mcofl till IIIII Nmenvoo HHN
mammcmn

mp m wze: m one: manna Hmuuo:|.p AN
ma ma wco: m can: canon mcgpoamo x
m.v m w m.% mcnc flaws“ Aaumv omwmaa NH

m mu m. M 0:03 wczom mmeHm HHH>

0')
,_4

n.a m vzacm carom onv accocam HH>

LO

0
H
._o
a J

0
LP:
.0

.H m nunn% vzgcm Aoa-v Hoscofig H>

mflwmeCmucoo

 

 

mwwmwy umao Mug

mamazmn msouzun mmomcca Humqouzp
Havana; 32.0%an T6,.“ H35; H.950: 0351.126
aaubmu Humuaaugu n.pu u a.ugmu wggqm.m.u Managuuma mm UodwfiunonH

Aswaav Aaaaflv
m-ooa om-pm AEEHHV mm AseHHv mm op->w ovum“ sawgompm

 

:T I).

DI SCUSS 10.7.;

The condensation of dimethyl tert.fbutyl carbincl at
at higher temperatures leads to larger quantities of split
products than at lower temperatures, as is to be expected.

The condensation of the dehydration product of
this alcohol is greatly aided by the presence of large
quantities of HCl. However, condensation of the alkene
does not give the chloride of the alcohol as a product iso-
lated at the end of the reaction, as is the case with-the
condensation of the alcohol itself. This would indicate that
the mechanism suggested by Tsukervanik is not correct.' His
mechanism is based on the formation of the chloride (and
alkenc) as byproducts in the condensation of the alcohol‘
and would, of course, predict the isolation of the chloride
in the condensation of the alkene. The fact that aluminum
chloride complexes with tert.-butyl alcohol give no tert.é
butyl benzene when mixed with benzene is another criticism
of this mechanisnu

The formation of the split products by mixing tart.-
heptyl benzene with aluminum chloride indicates-the rever-
sibility of the alkylation-reaction.o This reversibility
of alkylation, especially with tertiary alkyl groups has
been demonstrated by other workers (52), This is.strongl.n

evidence in favor of an ionic mechanism. This reversibility

 

would not be expected if as unsaturaticn mechanism is to
be taken as correct.

0n the basis of the fries theory it would appear t“. at
the carbonium ion is formed either from he alcohol, the
chloride, the alkene, or the tert.-heptyl benzene. This
cation partially fragmentates as a result of th a weakening
of the 0-6 bonds.

0K3 CH-+ ca * “0:15 nrotcn
C: -n .- 3 I7. —-'—.—i———-—}C n- 7r- .
3 :73 31 —) C 3.077 + n1? 811 ft “-C‘ CH3
(-41.3 Cuts C‘*3 VA -33

The tert.-butyl cation then attacks benzene to form.tert.-
butyl benzene. 116 propcne adds on hCl to form isoprcpyl
chloride. lie reason why the isopropyl chloride does not
form cumene in the presence of benzene is not clear. Gen-
erally, however, secondary groups require more aluminum
chloride than tertiary for the alkylation of benzene.

The results of table IV'would also indicate that the
tert.-amyl group is formed from the tert.-heptyl cation of
the alkene, which is somewhat different from that formed
directly from the alcohol. the chloride or the alkyl benzene.
Since the alcohol gives small quantities of the tert.-amyl
group it might be scanned t21at the alcohol rm 3 partially
dehydrated to give the intermediate alhere which subsequently
forms the ionic substance with aluminum chloride.

It would appear that the trimcthyl styrene (found in
all condensaticns) is formed non-ionically from.the tert.~

heptyl benzene. The lcs s of an alkyl group from the carbon

Cl

atom of highly branched alkyl‘benzenes has been observed by
other yorkers (6).| lhere is no reason to suppose that ;
<xntert.-butyl styrene could not and did not forms ltsgfor+«
mation would be accounted for by the loss of only one methyl
group from the alkyl benzene..

The formation of trimethyl styrene and tert.—amyl ben-
zene can only be accounted ior by the rupture of the 7A3-3’
C-C bondof the alkyl group. Schmidt (53) has shown that
the enzymatic decomposition of carbohydrates and the cracking
of hydrocarbons is probably proceeded by the formation of
a double bond which so neakens thefleJ/bond as to cause the
splitting at that point. If his double bond rule-can be -

applied here, the formation of these compounds could be readily

explained.
. :1 :1 A10]. ' CHQAICL- ' : " ‘;'::
. ”“5 g 2 3 ' Y A. 6 --? tert.-a.myl
.1311,» CH, ass
0 0.)
CI C" 11 5 H
I5 115 . C3. C3 CEI EL. C_-.
Clis-C - C+ +I{C' 'CH """ C}; -C S? C é C '03
'T ll 6—- 3 7
01.3 0113 ,. ~ 0113 01.3 .. ..
13x SCH .0, :03
c- H' C‘-
H H
H . . E
. CHE, - C - 0113 CHZ) . C.'.
1 f Cils-C’- C " C CH logs of 0115-0 I C " C. .81:
-__C?raal—o ’ Oils 013 la .. If a}? :: o.
*4 +53, ..cn shifting 9 1:0 . con
E Q" of double 'C'°
1: bond H

 

 

Ch
’0

On the basis of the Price theory, an overall mechanism

for the reaction of the alcohol is suggested

 

0113 CH 01-:3 cz:g* -
0113-0 - 0 111-1110”: 01150 - c + 110211015
0113 01:5 C133 C115
CH 11..
\———V cars-C E 8 "
ens 01-13
4- 4
01:3 115 0:13 0:13 11:5 0113
CH3-CT- c +C6EI6‘Z’CH3-C-- c - 0611 (:1 C215— c - c '- 051151- 11*
Cds CH5 cos CH3 CH3 013
g.
_‘ 0:25 * _‘ 0:13 _) CI! . .
——-) Gus-C" e6116<__ CII3- c - C5116 cis- c ’- c615+11
0.13 (22:,
-c- +1101—) moi
above set of
CH3 SH3 CH3 CHQA1013 reactions
C13- 0 - + 111013;: ens-c - c+ + _
CHs CBS C313 C325 H C?
\) OKs-C- C 6376 set.
21 on.
20111
0113 01-13
on -c - C - (Mir—9011-0 : c - 0 uses}:
:5 , . 6 .> :5 , 6 5 :5

The chloride of the alcohol then arises-from the action of
Cl on the tert.-heptyl cation. The unsaturated gasses
evolved during the reaction may come from the methylene groups

liberated, the propene, or isobutene.

 

“ ._' at by

An explanation of the facts on the basis of the theories *
of Thomas or Daugherty would be similiar to that suggested
above since in both the alkyl group is converted into a pos-
itive ion.
The system of equations above was evolved to explain
the facts observed. Its only value lies in its ability to

accomplish this end.

1.

2.

3.

4.

6.

7.

64

 

SM “ "a

A spinning band fractionating column designed for vacuum
distillation has been constructed

The plate value of this column has been determined to

be 25, and the holdup per plate to be .1 oc._

Dimethyl tert.-butyl carbinol has been prepared and
condensed with benzene.

The products which have been isolated and identified
from.this condensation are:_isopropyl chloride; 2,2,5-
trimethyl butane-l}2,2,3ftrimethyl Zeohloro butane;-
tert.-butyl_benzene;_tert.-amyl benzene; trimethyl sty-
rene; and 2,2.3-trimethyl 2-phenyl butane.

All of these products and their derivatives have been
synthesized.

The dehydration product and the chloride of the above
alcohol have been condensed and some of the products
identified.

Dimethyl tert.-butyl phenyl methane has been mixed with
benzene and aluminum chloride to give some of the products

also isolated in the condensation of the alcohol.

1o
2.
3o
4..
5o

6.

79
8.
9.

10.

11.
12.
13.

14.

15.

65

monocmpn

Lessons and Lochte, J. Ind. Eng. Anal. Ed..-12. 450 (1938)
Baker, Barkenbus and Roswell, ibid., 13. 468 (1940)
Whitmore and lux, J. Am. Chem. Soc.. £33~5448 (1932)
Zawidzki. Z. fur Phys. Chem.. 25, 129 (1990)

Tongberg, Fenske and Quiggle, J. Ind. Ens. Chem., go.
' 1215 (1954) .

Huston and Friedmann J. Am. Chem. Soc,,‘§§, 2527 (1916)
lbid., 39. 785 (1918)

Huston and Sager, ibid.. fig, 1955 (1926)
Huston and Goodemoot, ibid., go, 2432 (1934)

Huston and Hsieh, ibid., 59, 439 (1936) -
Huston, Fox. and Binder. T? Org. Chem..'§, 251 (1938)
Huston. Guile, Schulati and Wesson, ibid., g, 252 (1941)

Huston, J. Am. Chem. eoc.. 46, 2775 (1924)
Huston. Lewis and Grotemut.-fbid.. 49,1565 (1927)
IEuston and IIedrick, ibid.. _5__9_, 200171937)
Huston and Guile. ibid.. §_1_, 69(1939)

Huston and Jackson. ibid., £9,541 (1941) -
Huston and Hughes, Ph.D. Thesis. rich. State-College (1940)-

hUston and Kaye. Ph.D. Thesis. Kich. State College (1942)
Huston and Esterddhl, “.3. Thesis, Rich. State Calls 0 (1940)
Huston and Curtis, K.S. Thesis. Kich. State College fl941)

Huston and Lewis, J. Am Chem. Soc.. pg, 2:579 (1931)
Inston. Swartout and Wardwell, ibid., 52,4484 (1930)
Huston and Iiouls, ibid., 25., 1506 (19:527"

Tsukervanik, J. Gen. Chem. (USSR). 5, 117 (1935)
C. A. 142.4746
Ibid. 3. 623 1937 - c; A. g. 5778

 

15.

27.
24s

Tsukervanik, ibid.. 7, 637 (1957) - C. A. $1,5780
Ibid.. 5. 1512 (1938 - c. A. 33, 4o 7
Ibid.’ §,1899 193;: t :0 A. E, 5833

telsh and Drake, J. Am. Chem. Soc...gg. 59 (1938)

Corrie and In rehau. ibid., 60,1421 (1935)
Lorrie and Sturgis, ibid.. 6-. 1415 (1939)

Ipatieff. iinee and Schmcrling. ibid.. 3;, 2991 (1940)

hefienna and Bose, ibid., Q2, 479 (1937)
Perrier and Iouget. Bull. Soc. Chim.. (3),

ertse. C. Z. 1931 II. 1691

Huston and Evert. 1.3. Thesis, Eich. State College (193

CUEtaYBOD, 27.2.11. T99. ¢}25.f5... (2). g}... 71 (1879)
Bougherty, J. Am. Chem. Soc..'§l, 57C (1929)
Prins. Chem. Lcckblad.,Ԥ5, 615 (1927)

Grosse and Ipatieff, J. Org. Chem., 2; 559 (1937;

25. 551 (1901}

1‘.
,
w

Thomas, Anhydrous aluminum chloride in Organic Chemistryo

Price. Clicm. Rev., 29, 44 (1941)

Ulioh and Kayne, Z. Elec. Chem., 5;, 5C9 (1935)
Certyporech. Ann., 500, 287 (1933)

Eahitmore. J. Am. Chem. Soc.. ‘gfi, 3274 (1932
Price and Cistowski, ibid.. _g, 2493 (1939
Butlerow. Ann.. 111, 176 (1875)

Bogololcz, ibid., Egg, 7C. (1C.Cl )

fiaschirsky. J.I Russ. ..JJ-c :em Gee., I», CC (1981)
Henry, Compt. Rc-nd.. 1.2.1023 (19C5)

ficnry. C. 2.. 1900 II, 44?

Ibid. 190? II, 447

Ibid, 1303.748

Henry, Compt. 3end.. 1I3. 20 (1% ')

Edgar, Calingaert and Corker. J. Am. Chem. Soc.,

f1
”1,
-

A”?

‘3'

.“ ‘J

on

p 72

(1929?

(-1

 

43.
44.
45.
46.
47.
4s.

7

Whitmore, ibid.. §§, 1559 (1953)

Euston and Binder, K.S. Thesis, Kich. State College (1935)
Euston and Hedrick, IK.D. Thesis. Eich State 0111ege (1937)
Organic Synthesis, V, 87-91

Organic Synthesis, VIII. 104

Shriner and Fuson. The Systematic Identification of
Organic Compou1~.ds - p 152

Ipatieff and Sohmerling, J. Am. Chem. Soc., 59,1056 (1937)
Ibid.. 60,1478 (1938)

Shriner and Fuson, p 142

Lucas, Compt. Rend.. 150.1059 (1913)
Hales , J. Praokt. Chem. (2), 89, 451 (1914)
Schmidt. Chem. 2cv.. 21, 137 (1935)

 

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