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Патент USA US3093703

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3,093,694
United States Patent 0
_ Patented June 11, 1963
1
2
may be used, but proportions from 0.5 to 10 parts by
weight of diluent per vpartv of aryl hydrocarbon are
3,093,694
METHOD FOR PREPARING ISOPROPENYL
> preferred.
. SUBSTITUTED ARYL HYDROCARBONS.
Frederick J. Soderquist, Essexville, James L. Amos, Mid
land, and Harold vD. Boyce, Coleman, Mich., assignors
to‘ The Dow Chemical Company, Midland, Mich., a
corporation of Delaware
-
No Drawing. Filed May 19, 1960, Ser. No. 30,069
9 Claims. (Cl. 260-669)
It is to be understood that n-butyl aryl hydrocarbons
are not operable starting materials for the preparation of
isoprop enyl-aryl hydrocarbons in the method of the present
invention. For example, products arising ‘from the use of
n-butylbenzene as a starting material include toluene,
styrene, naphthalene and indene; however, no detectable
,10 amount of isopropenylbenzene is found in the reaction
product.
This invention relates to a process for preparing iso
propenyl-substituted aryl hydrocarbons. Speci?cally, the
Also, it is known that o-vinyltoluene can be prepared
invention relates to preparing compounds having from one
from ortho-n-propyltoluene (see US. Patent 2,857,440‘ to
to two isopropenyl substituents in the aryl nucleus.
Amos, ‘Soderquist, and Allen). However, in view of this
The starting material employed for carrying out the 15 known demethanation of the ortho-n-propyl compound,
method of the present invention is a mono- or ditertiary
it is totally unexpected that, in the method of the present
butyl-substituted a-ryl hydrocarbon. This starting material
invention, the tertiarydbutylbenzene is- easily demethanated,
whereas the n~butylbenzene is totally inoperable.
may contain in the aryl nucleus one or more substituent
‘groups which are non-reactive under the conditions of the
The practice of the present invention is illustrated by a
process. Such non-reactive groups may be, for instance, 20 series of experiments in which a tertiary-butylbenzene,
methyl or a halogen having an atomic weight of less
or substituted tertiary-butylbenzene was vfed at the rate
‘than 80.
of 10-30 grams per hour into a stainless steel reactor tube
The method of the present invention is conveniently
having an inner diameter of ‘0.8" and a length of 36"
practiced by passing an aryl hydrocarbon, of the type
and maintained vertically in an electric ‘furnace. In some
hereinbefore described, in the gaseous state, through a 25 of the experiments, the feed stock was admixed with
reaction zone wherein the temperature is maintained at
steam as an inert diluent, while in other experiments a
from 500° to 800° (3., preferably at from about 650-750°
C., cooling and condensing the e?luent vapors, and sepa
demethanation catalyst was employed, both with and with
out the diluent. The upper portion of the reactor tube
rating the desired i-sopropenyl-substituted aryl hydrocar—
bon from the total reaction product.
comprised a pre-heat zone for the in?uent reactant material
30 and was maintained at 200-350” C. The temperature in
The reaction can be carried out at atmospheric, sub
the central portion of the reactor was maintained constant
for each experiment, the feed stock was introduced into
atmospheric, or super-atmospheric pressures, as desired;
however, as a matter of convenience, atmospheric pressure
is preferred.
the reactor and subjected to that temperature, and the
e?luent collected. This procedure was then repeated at a
7
While a catalyst is not essential, a demethanation 35 series of temperatures ranging from 500—750° C. The
e?luent gas stream was cooled and condensed by passage
through a heat exchanger, and from the condensed prod
method of the present invention. Said catalysts are
uct the liquid hydrocarbon layer was isolated and analyzed
catalyst, preferably of the self-regenerating type, and se
lected from the known species, may be employed in the
typically composed of iron oxide, zinc oxide, chromium
by infra-red spectrometry.
oxide, and activated alumina, taken singly or in combina
tion. The preparation of said catalysts is described in
,
There are shown in Table I the hydrocarbon employed
as feedstock and its feed rate, the feed rate of the steam
several US. Patents (see 2,370,797; 2,395,875; 2,395,876;
2,418,888; and 2,426,829).
diluent (when used), the catalyst employed, if any, the
rate of recovery of total organic condensate at each of
The method of the present invention may be carried
a series of operating temperatures, the percent feed stock
out with the tertiarydbutyl aryl hydrocarbon alone or in 45 converted to other products, and the yield of demethanated
admixture with an inert diluent. Suitable ‘diluents include
product obtained at each temperature, based on the per
benzene, toluene, steam, nitrogen, and carbon dioxide;
cent feed-stock consumed. For purposes of comparison,
virtually any proportion of diluent to aryl hydrocarbon
n-butylbenzene was also used as feed stock. It is to be
ExperlFeed rate
ment Hydrocarbon employed of hydroNo.
carbon,
Diluent,
Catalyst
Temp,
gJhr.
° 0.
gJhr.
1 ______ __
Tert-butylbenzene __ . _
22. 4
2 ___________ __d0 _______________ __
22. 4
22. 4
21. 4
21. 4
21. 4
21. 4
20. 0
20. 0
20. 0
19. 5
19. 5
19. 5
19. 5
20. 8
20. 8
20. 4
20. 4
___
_____d0_.___
N-butylbenzene
Recovery
Hydrocarbon
rate gJhr.
converted,
yield,
percent
percent
‘
mot-Ono, _____ __
0
_____do ______ --
--
Isopropenyl
benzene
600
18
22
30
650
17
34
35
700
550
600
650
700
600
650
700
650
600
650
700
650
700
700
750
15
20
20
13
9
20
18
15
20
19
11
10
18
18
19
17
62
9
21
66
96
14
55
92
13
37
86
99
26
72
49
100
41
68
57
58
18
76
61
25
64
46
34
32
65
71
24
68
21. 0
700
16
86
36
21.0
21. 3
21. 3
21. 3
16. 8
16. 8
16. 8
750
600
650
700
600
650
700
19
19
18
17
15
12
11
100
12
19
47
41
76
76
45
0
0
0
0
0
0
3,093,694
4
substituents reactive in the process, through a reaction
zone at a temperature of 500-800° C., thereby e?eoting
substantial demethanation of the tertiarydbutyl groups;
understood that when p-ter-tiary-butyltoluene and p-di
tertiary-butylbenzene were employed as feed stock, the
products obtained were p-isopropenyltoluene and p-diiso
propenylbenzene, respectively, and that these are the prod
condensing the e?luent vapors and separating the isopro
penyl aryl compound from the condensate.
ucts listed under “Yield.”
2. A method as de?ned in claim 1 wherein the tertiary
It is to be understood that in addition to the compounds
prepared as hereinbefore described, other starting ma~
terials may ‘be employed in the method of the present in
butyl substituted compound is a tertiary-butylbenzene.
3. A method as in claim 2 wherein the tertiary-butyl
benzene fed to the reaction zone is admixed with an inert
vention, such as o-ditertiary-butylbenzene, m-ditertiary
butylbenzene, o-tertiary-butyltoluene, m-tertiary-butyl
toluene, 2,4-dichloro-tertiary-butylbenzene, 2,5-diphenyl
10
diluent.
4. A method as in claim 1 wherein the reaction tem
perature is maintained at between 650° C. and 750° C.
5. A method as in claim 2 wherein the tertiary-butyl
zene, 4-bromo-1,3-ditertiary-butylbenzene, 5-phenyl-1,2
benzene is contacted with a demethanation catalyst.
ditertiary-butylbenzene, 1-tertiary-butylnaphtha1ene, 2,4
ditertiary-butylnaphthalene, 3chloro-5-tertiary-butylnaph 15 6. A method as in claim 2 wherein the butylbenzene is
tertiary - butylbenzene,
3 - chloro-1,2-ditertiary-butylben
tertiary-‘butylbenzene.
thalene, Z-methyl-S-tertiary-butylnaphthalene, 3-chloro-5
bromo-S-tertiary-butylnaphthalene, 2,4-ditertiary-butylan
7. A method as in claim 2 wherein the butylbenzene is
p-ditertiary-butylbenzene.
thracene, 2-chloro-S-tertiary-butylanthracene, 3-bromo-6
chloro - 7 - tertiarydbutylanthracene,
8. A method as in claim 2 wherein the butylbenzene is
1-methy1-2-ch1oro-5
tertiary-butylanthracene, 2-tertiary-butylphenanthrene, 2
chloro-3-methy1-6-tertiary-butylphenanthrene, 2,5-diterti
20
ary-butylphenanthrene, and the like, and analogous prod
ucts obtained therefrom.
We claim:
1. A process for preparing isopropenyl-substituted aryl 25
compounds having from one to two isopropenyl substitu
ents in the aryl nucleus, said process comprising passing a
gaseous tertiary-butyl-substituted aryl compound having
vfrom one to two tertiary-butyl groups as the only nuclear
p-tertiary-butyltoluene.
9. A method as in claim 3 wherein the inert diluent is
steam.
References Cited in the ?le of this patent
UNITED STATES PATENTS
1,552,875
Ostromislansky et al _____ __ Sept. 8, 1925
2,110,830
2,939,889
Driesbach _____________ __ Mar. 8, 1938
Amos et al _____________ __ June 7, 1960
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