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Патент USA US3052745

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United States Patent 0 ’ ICC.
3,052,737
Patented Sept. 4, 1962
2
1
18 carbon atoms, preferably between 2 and 4 carbon
atoms. The alkenyl radicals may be essentially straight
3,052,737
SYNTHESIS OF ALKENYL SUBSTITUTED
chain or may be branched chain in con?guration. The
CYCLOALKANES
cycloalkene radicals are preferably monocycloalkene and
Lynn H. Slaugh, Pleasant Hill, Calif., assignor to Shell 5 lbicycloalkenes and include those having from 5 to 8 car
Oil Company, a corporation of Delaware
bon atoms each. Other hydrocarbon radicals may be ap
No Drawing. Filed Dec. 21, 1959, Ser. No. 860,694
pended to the cycloalkene radical, particularly alkyl radi
2 Claims. (Cl. 260-666)
cals having from 1 to 5 carbon atoms each, more particu
larly 1-3 carbon atoms each.
This invention relates to the conversion of alkenyl cy
cloalkenes to the corresponding alkenyl substituted cyclo 10 The following list of species include typical alkenyl
cycloalkenes which may be ‘treated in accordance with
alkanes. It deals particularly with a new method for
this invention:
producing such materials in unexpectedly high yield.
The reduction of polar compounds is relatively easy to
l-vinyl-l-cyclopentene
carry out by well established methods. Special processes
l-vinyl-l-cyclohexene
have been devised also for the selective reduction of the 15
4-viny1-l-cyclohexene
polar radicals of unsaturated polar compounds, such as
l-propeny1-1-cyclopentene
unsaturated aldehydes ‘and the like, without at the same
l-allyl-l-cyclohexene
time affecting the degree of saturation of the ole?nic
l-propeny1-1—cyclohexene
bonds. Corresponding reactions involving the selective
1-methyl-4-ethylidene-l-cyclohexene
reduction of a particular ole?nic bond while leaving un 20
affected the other ole?nic bond in the same molecule of a
hydrocarbon have not vbeen studied up to the present time.
It is an object of the present invention to provide a
process for the preparation of alkenyl substituted cyclo
1,5-dimethyl-3-vinyl-l-cyclohexane
l-methyl-Z-isopropenyl-l-cyciopentene
l-methyl-3-isopropylidene-l-cyclohexene
1-isobutenyl-1~cyclohexene
2-methyl-3-isopropenyl-l-cyclohexene
alkanes. It is a particular object of the invention to pro 25
vide a process for the conversion of alkenyl substituted
3-methyl-4-isopropenyl-l-cyclohexene
cycloalkenes to the corresponding alkenyl cycloalkanes.
5-methyl-3-allyl-l-cyclohexene
1smethyl-4-isopropenyl-l-cyclohexene
It is a special object of the invention to provide a process
Vinyl bicycloheptenes, octenes, etc.
with the above objectives in view wherein particularly
The
polycyclic
fused ring hydrocarbons with which the
30
high yields are obtained. Other objects and advantages
alkenyl cycloalkenes form adducts in the ?rst step of the
of ‘the invention will become apparent from the following
present process include especially those having at least 3
description of the process and the reactions employed
rings per molecule as typi?ed by anthracene and must
therein.
contain at least 2 meso carbon atoms per molecule in a
Now, in accordance with the present invention, a proc
ess is provided wherein adducts are formed between an 35 1-4 relationship to each other. The following species are
typical of the polycyclic compounds which may be em
alkenyl-substituted cycloole?nic hydrocarbon and a poly
ployed, the preferred species being anthracene. Alkylated
cyclic lfused ring hydrocarbon containing in the molecule
derivatives of these polycyclic hydrocarbons may be uti
at least 2 meso carbon atoms in a 1-4 relationship to each
lized but the unsubstituted hydrocarbons are preferred.
other and which can act as a diene in a Diels Alder reac
tion and in which the double bond formed during this 40
Anthracene
reaction is contained in an aromatic ring, hydrogenating
Benz-as-indacene
the ole?nic linkage contained in the cycloole?n ring, and
Napthacene
pyrolyzing the resulting product to regenerate the poly
1,2-1benzanthracene
cyclic fused ring hydrocarbon and an alkenyl substituted
Pentacene
45,
cycloalkane.
Hexacene
The process according to this invention is based upon
the discovery that selective adduct formation occurs be
tween a more reactive ole?nic linkage which is present
in vthe alkenyl radical as compared with the less reactive 50
ole?nic linkage present in the cyclo-ole?n group. It is
possible that such selective formation may take place in
diole?ns not containing a cycle-ole?n radical as a part of
the molecule, but such adduct formation results in a
mixture containing a substantial proportion of adducts
wherein the linkage between the polycyclic fused ring
hydrocarbon is with one of the ole?nic linkages of the
diole?n and also substantial amounts of adducts wherein
the linkage is [between the fused ring polycyclic hydro
carbon and the other ole?nic linkage of the aliphatic di
ole?n. Hence, the present process has been found to be
especially desirable where high yields of a particular
product are desired rather than a mixture of products.
l-Cyclopent (a) Anthracene
l-Cyclopent (a) Anthracene
B-anthrindane
Benzonapthacene
Dibenzanthracenes
(ac), (ai) (ah)
The formation of the adducts in the ?rst step of the
process can be readily carried out by simply heating at
least 1 alkenyl cycloalkene with at least one of the con
jugated polycyclic hydrocarbons described above. Tem
peratures of about 150° C. to about 275° C. can be used.
However, a temperature between about 200 and 250° C.
is preferred in order to secure the high conversions ex
perienced within reasonably short reaction times. It is
usually necessary to heat [the ingredients together for a
time in excess of about 4 hours and usually between about
4 and 16 hours since the hydrocarbons of this particular
The alkenyl cycloalkenes include particularly those in
type do not form adducts as readily with the polycyclic
which the alkenyl radical contains between 2 and about 65 conjugated hydrocarbons as otherwise materials hereto
3,052,737
3
4
fore employed in the formation of adducts of somewhat
similar con?guration. Pressures in the order of about
sub-atmospheric pressures are also sometimes advantage
ous in promoting prompt removal of the alkenyl cyclo
50~5000 pounds per square inch are advisable. The reac
tion may or may not be carried out in the presence of a
alkene.
Such removal is advantageous in any cases as a
hydrocarbon ‘solvent which does not take part in the
adduct formation. Suitable hydrocarbon solvents include
means of preventing undesirable further reaction of the
product. As a rule, heating for a period of about 2 to
about 60 minutes is su?icient for ‘substantially complete
benzene, toluene, para?ins, gasoline or kerosene fractions
pyrolysis to the desired products.
from about 1 part of the hydrocarbon solvent to about
100 parts or more per part of alkenyl cycloalkene can be
employed.
In a typical preparation the ?rst step was carried out
as follows: Anthracene (1.7 moles) and 4-vinylcyclo
10 hexene-l (9.2 moles) together with 800 cc. of toluene
Stoichiometric‘ proportions or an excess of either of
were heated at about 225° C. for about 16 hours at a
the vreactants canbe used in forming the adducts but an
excess of ole?n is preferred. Advantageous ratios of
about ‘1 to 2 moles of one of the reactants per mole of
the other reactant are preferred.
15
pressure of about 150 psi. The product comprised about
85% by weight of a novel compound, namely, the adduct
of anthraceneand 4-vinylcyclohexene-1, which is 9,10-di-.
hydro-9,l‘0[cyclohex-3-enyl]ethanoanthracene. In addi
- Itis usually unnecessary to separate the adduct from
tion to this relatively pure adduct which was a crystalline
the reactionmixture in which it is prepared, although it
material, a non-crystalline product was also obtained in
about 14.6% yield. This was later found to be a mix
is usually desirable particularly where in excess of one
ture of the adduct together with a dimer of vinyl cyclo
of the reactants has been employed in forming the adduct
to remove any un'reacte’d component before using the ad 20 hexene and other byproducts. This may be pyrolyzed to
recover 4-vinylcyclohexene and anthracene.
duct in the reduction step of the process. . The thus re
covered reactant can then be recycled for further adduct
The same results were obtained in the absence of any
formation.
solvent, the recovery of adduct being virtually theoretical.
Shorter reaction times in the order of about 6 hours
The reduction of the ole?nic group of groups of the
adduct formed in the ?rst step of the process can be 25 could be utilized if temperatures of about 250° C. were
carried out in a number of different ways by reaction
employed, if a less pure product can be tolerated and less
with hydrogen.
than complete reaction is acceptable.
The second step of the process, namely, the hydrogena
Catalytic hydrogenation can be carried
out with the crude mixture from the adduct formation
step preferably after removal of unconverted starting
tion of the adduct, was carried out by hydrogenation over
reactants but ‘most preferably without removal of the 30 Raney nickel at a temperature of about 125° C. and
solvent if solvent was used, by suspending a hydrogen
750 pounds per inch pressure in the presence of iso
tion catalyst therein or otherwise contacting the mixture
propyl alcohol to obtain an essentially theoretical yield
with the catalyst and subjecting the whole to the action
of the hydrogenated adduct, the only point of hydrogena
.
,
tion being the double bond of the cyclohexene ring.
Any of the hydrogenation catalysts known to the art 35 Hydrogenation was also carried out on a corresponding
may be used with .varying degrees of effectiveness in the
sample in the presence of dimethyl ether of diethylene
hydrogenation step of the present process. Of those
glycol as the medium. In this case, the temperature was
of hydrogen.
which are especially adapted to use in accordance with the
present invention, the catalysts known to the art as
about 50° C. and the pressure utilized was about 500
pounds per square inch to obtain about a 93% yield of
,
Raney’s nickel and Adam’s platinum catalyst are very 40 the hydrogenated adduct.
e?‘icacious from the standpoints of both cost and e?i
The pyrolysis of the hydrogenated adduct was easily
ciency. Other suitable hydrogenation catalysts are those
carried out by simply heating the product from the fore
going step at a temperature in the order of 330° C. to
consisting of or comprising one or more metals, or cata
lytically active compounds of metals, such as Fe, Co, Cu,
Pd, Zr, Ti, Th, V, Pt, Ta, Ag, Mo, Al, and the like.
The catalysts can be used with or without inert or cata
lytically active carriers or supports or activators.
obtain essentially theoretical yields of anthracene and of
45
vinylcyclohexane. The impure, non-crystalline hydro
genated adduct was also pyrolyzed under similar condi
tions to recover anthracene and impure vinylcyclohexane.
The latter compound, vinylcyclohexane, has been found
" Inv a preferred case e.g., when ‘Raney nickel is em
.ployed as the hydrogenation catalyst in an amount from
to be an important monomer for use in the preparation
about 2% to about 10% of the product to be hydro 50 of polymers by the Ziegler process.
genated, the hydrogenation may be effected satisfactorily
I claim as my invention:
at temperatures of from about 30° C. to about 150° C.,
for example from about 50° to 125° C., and under hy
drogen pressures of from about 50 toabout 5000 pounds h
1. A process for producing vinylcyclohexane which
or more per square inch.
When other catalysts are em
ployed, conditionsleadingto an equivalent degree of
hydrogenation are preferably employed. Hydrogenation
‘
comprises adducting 4-vinylcyclohexene-1. as dienophile
with anthracene as diene in a Diels-Alder reaction at a
55 temperature between about 150 to 275° C., selectively
catalyticallyvhydrogenating the cyclohexene ring of the
resulting 9,10-dihydro-9,10-(cyclohex-3-enyl)
ethano
anthracene with free hydrogen in the presence of a hydro
times of the order of about 0.5 to 8 hours are usually
suf?cient. At the conclusion of the hydrogenation, the
genation catalyst at a temperature between about 30° C.
catalyst can be separated from the mixture as by ?ltra 60 and about 150° C. under a hydrogen pressure between
tion, for example, and reused in the process. In some
about 50 and about 5000 pounds per square inch, and
pyrolyzing the hydrogenation product at a temperature
cases a reactivation treatment may _be desirable before
such reuse‘ of the ‘catalyst.
I
'
between about 330° C. and about 400° C. to produce
vinylcyclohexane and regenerate anthracene.
Whateverl'method of reduction is employed the result
ing products can be decomposed as’ previously indicated 65 ’ 2. A process for producing vinylcyclohexane which
to liberate the desired alkenyl cycloalkane corresponding
to the starting alkenyl cycloalkene and to regenerate the
polycyclic fused ring hydrocarbon for reuse in the ?rst
step of they process. It has been found that pyrolysis of
comprises adducting 4-vinylcyclohexene-1 with anthracene
in a liquid hydrocarbon solvent at a temperature between
about 200° C. and about 250° C., hydrogenating the
,cyclohexene ring of the resulting 9,10-dihydro-9,10-[cyclo
the reduced adduct is one of the most advantageous 70 hex-3-enyl] ethano-anthracene by reaction with gaseous
hydrogen at a temperature between about 50° C. and
of the reduced- adduct at temperatures between about
about 125° C. under a hydrogen pressure between about
250° C. and 4509C. (preferably 330-400° C.) is usually
50 and about 5000 pounds per square inch in the presence
methods of carrying out such decomposition. Heating
effective.v The pyrolysis is preferably carried out at ordi
of a Raney nickel catalyst, and pyrolyzing the hydrogena
nary pressures, although higher pressures can be used and 75 tion product at a temperature between about 330° C
3,052,737
5
and about 400° C. to produce vinylcyclohexane and re-
generate anthracene-
References Cited in the ?le of this patent
UNITED STATES PATENTS
2,406,645
Thomas ------------ -- Aug- 27, 1946
6
2,673,886
Steadman __________ __ Mar. 30, 1954
OTHER REFERENCES
“The Diem Synthesis,” by K- Alder in “Newer Methods
5 Preparatwe Orgamc Chem1stry,” pages 381 to 511 (pages
434, 488 and 494 only needed). Interscience Publishers
Inc., New York, NewYork(1948),
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