US3502736A

US3502736A - Oxidative dehydrogenation of non-aromatic cyclic hydrocarbon having at least one unsaturated bond in side chain

Info

Publication number: US3502736A
Application number: US666970A
Authority: US
Inventors: Mikio Sato; Kinya Tawara
Original assignee: Maruzen Oil Co Ltd
Current assignee: Cosmo Oil Co Ltd
Priority date: 1966-09-12
Filing date: 1967-09-11
Publication date: 1970-03-24
Anticipated expiration: 1987-03-24

Description

United States Patent 3,502,736 OXIDATIVE DEHYDROGENATION 0F NoN- AROMATIC CYCLIC HYDROCARBON HAV- ING AT LEAST oNE UNSATURATED BOND IN sIDE CHAIN 5 Mikio Sato and Kinya Tawara, Chiba-shi, Japan, assignors to Maruzen Oil Company Limited, Osaka, Japan N0 Drawing. Filed Sept.11, 1967, Ser. No. 666,970

Claims priority, applicla/tggn Japan, Sept. 12, 1966, 4 19 Int. Cl. c07 5/18, 15/10 US. or. 260669 I 9 Claims ABSTRACT OF THE DISCLOSURE The present invention relates to a method for the oxidative dehydrogenation of a non-aromatic cyclic hydrocarbon having at least one unsaturated bond in a side chain.

Hitherto, it has been known that the dehydrogenation of anon-aromatic cyclic hydrocarbon to the corresponding aromatic hydrocarbon can be accomplished by contacting the non-aromatic cyclic hydrocarbon with palladium metal, platinum metal, nickel metal or chromium oxide in the absence of oxygen at an elevated temperature. When the non-aromatic cyclic hydrocarbon has a side chain including an unsaturated bond, however, the unsaturated bond is hydrogenated in such process. For instance, 4-vinylcyclohexene-1 is dehydrogenated at 400 C. in the presence of chromium oxide to give as the main product ethylbenzene [Chemical Abstracts, vol. 34, col. 5418 (1940)]. Further, for instance, the dehydrogenation of 4-vinylcyclohexene-1 at 290 to 300 C. in the presence of palladium metal yields solely ethylbenzene [Chemical Abstracts, vol. v53, col. 3329 (1939)]. Even when the dehydrogenation in the latter case is effected at a lower temperature, i.e. 135 to 150 C., there proceeds a disproportionation reaction to afford a mixture of ethylbenzene and ethylcyclohexane as shown in the following formulae:

CHzCHg Thus, the dehydrogenation of a non-aromatic cyclic hydrocarbon having an unsaturated bond in a side chain to the corresponding aromatic hydrocarbon retaining the unsaturated bond in an appreciable conversion rate and selectivity has never been achieved.

In the course of the study seeking a method which can dehydrogenate a non-aromatic cyclic hydrocarbon having an unsaturated bond in a side chain selectively to the corresponding aromatic hydrocarbon retaining the unsaturated bond, the present inventors had found that a platinum group metal (e.g. palladium, platinum, rhodium, iridium, ruthenium, osmium) realizes such selective dehydrogenation when used in the presence of oxygen. Since ice the conversion rate is, however, considerably low, the said metal is not applicable to the industrial dehydrogenation.

As the result of the subsequent study, there has now been found that, when palladium oxyhydrate is used as a catalyst in the presence of oxygen, a non-aromatic cyclic hydrocarbon having an unsaturated bond in a side chain is dehydrogenated in a high conversion rate with an excellent selectivity to the corresponding aromatic hydrocarbon retaining the unsaturated bond.

Accordingly, a basic object of the present invention is to embody a method for the oxidative dehydrogenation of a non-aromatic cyclic hydrocarbon having at least one unsaturated bond in a side chain to the corresponding aromatic hydrocarbon retaining the unsaturated bond in a single step. Another object of this invention is to embody a process for the preparation of an aromatic hydrocarbon having an unsaturated bond in a side chain selectively from the corresponding non-aromatic cyclic hydrocarbon having an unsaturated bond in a side chain in a single step. A further object of the invention is to embody a catalyst which can dehydrogenate in the presence of oxygen a non-aromatic cyclic hydrocarbon having at least one unsaturated bond in a side chain to the corresponding aromatic hydrocarbon retaining the unsatu rated bond in a high conversion rate with an excellent selectivity. These and other objects will be apparent to those conversant with the art to which the present invention pertains from the foregoing and subsequent descriptions.

. According to the present invention, a non-aromatic cyclic hydrocarbon having at least one unsaturated bond in aside chain is contacted with a catalyst consisting essentially of palladium oxyhydrate in the presence of oxygen to give the corresponding aromatic hydrocarbon retaining the unsaturated bond as unchanged.

The non-aromatic cyclic hydrocarbon is monocyclic or polycyclic and has one or more side chains, of which at least one hears at least one unsaturated bond. Specifically, there are exemplified hydrocarbons respresented by either one of the following formulae:

L L m wherein X is a substituted or unsubtituted monocyclic or bicyclie non-aromatic hydrocarbon group such as cyclohexyl, lower alkylcyclohexyl (e.g. 2-rnethylcyclohexyl,

2-ethylcyclohexyl) di(lower)alkylcyclohexyl (e.g. 2,4-dimethylcyc1ohexyl,

2-methyl-4-ethylcyclohexyl tri (lower)a1kylcyclohexyl (e.g. 2,4,6-trimethylcyclohexyl,

2,4-dimethyl-6-ethylcyclohexyl) cyclohexenyl,

lower alkyleyclohexenyl (e.g. 2-methylcyclohexen-1-yl,

3-ethylcyclohexen-1-yl) di(lower) alkylcyclohexenyl (e.g. 2,4-dimethylcyclohexenl-yl,

Z-m thyl-4-ethylcyclohexen- 1-yl tri(lower)alkylcyclohexenyl (e.g. 2,4,6-trirnethylcyclohexen-l-yl,

2,6-dimethyl-4-ethylcyclohexenl-yl) cyclohexadienyl,

lower alkylcyclohexadienyl (e.g. 2-methylcyclohexadien- 2-ethylcyclohexadien-1, 3 -yl) di(lower)alkylcyclohexadienyl (e.g. 2,4-dimethylcyc1ohexadien-1,3-yl,

2,4-diethylcyclohcxadien-1,3-yl) tri(lower)alkylcyclohexadienyl (e.g. 2,4,6-trirnethylcyclohexadien-1,3-yl,

cyclohexadienyl-di (lower) alkylcyclohexadienyl (lower) alkene,

cyclohexadienyl-di (lower) alkylcyclohexyl (lower) alkene,

cyclohexadienyl-di (lower) alkylcyclohexenyl (lower) alkene,

cyclohexadienyl-tri (lower) alkylcyclohexyl (lower) alkene,

cyclohexadienyl-tri (lower) alkylcyclohexenyl (lower) alkene,

lower alkylcyclohexadienyl-lower alkylcyclohexadienyl- (lower) alkene,

lower alkylcyclohexadienyl-lower alkylcyclohexyl(lower) alkene,

lower alkylcyclohexadienyl-lower alkylcyclohexenyl- (lower) alkene,

lower alkylcyclohexadienyl-di (lower) alkylcyclohexadienyl (lower) alkene,

lower alkylcyclohexadienyl-di (lower) alkylcylohexyl- (l-owe'r)alkene,

lower alkylcyclohexadienyl-di (lower) alkylcyclohexenyl- (lower) alkene,

lower alkylcyclohexadienyl-tri (lower) alkylcyclohexadienyl (lower alkene,

lower alkylcyclohexadienyl-tri(lower) alkylcyclohexyl- (lower) alkene,

lower alkylcyclohexadiene-tri (lower) alkylcyclohexenyl- (lower) alkene,

di(lower)alkylcyclohexadienyl-di (lower) alkylcyclohexadienyl (lower) alkene,

di(lower) alkylcyclohexadienyl-di (lower) alkylcyclohexyl- (lower) alkene,

di (lower) alkylcyclohexadienyl-di (lower) alkylcyclohexenyl (lower) alkene,

di(lower) alkylcyclohexadienyl-tri (lower alkylcyclohexadienyl (lower alkene,

di( lower alkylcyclohexadienyl-tri (lower) alkylcyclohexyl (lower) alkene,

di (lower) alkylcyclohexadienyl-tri(lower) alkylcyclohexenyl (lower) alkene,

tri (lower) alkylcyclohexadienyl-tri (lower) alkylcyclohexadienyl (lower) alkene,

tri (lower) alkylcyclohexadienyl-tri (lower) alkylcyclohexyl (lower alkene,

tri(lower) alkylcyclohexadienyl-tri lower alkylcyclohexenyl (lower) alkene,

cyclohexadienyl-aryl (lower alkene,

lower alkylcyclohexadienyl-aryl (lower) alkene,

di (lower) alkylcyclohexadienyl-aryl (lower) alkene,

tri(lower alkylcyclohexadienyl-aryl(lower) alkene,

lower alkenylperhydronaphthalene,

lower alkyl-lower alkenylperhydronaphthalene,

di (lower) alkyl-lower alkenylperhydronaphthalene,

tri(lower)-alkyl-lower alkenylperhydronaphthalene,

di (lower) alkenylperhydron aphthalene,

lower alkyl-di(lower) alkenylperhydronaphthalene,

di (lower) alkyl-di (lower) alkenylperhydronaphthalene,

tri(lower) alkyl-di (lower) alkenylperhydronaphthalene,

tri (lower) alkeuylperhydronaphthalene,

lower alkyl-tri(lower alkenylperhydron aphthalene,

di(lower) alkyl-tri (lower) alkenylperhydronaphthalene,

tri( lower) alkyl-tri (lower) alkenylperhydronaphthalene,

lower alkenyltetrahydronaphthalene,

lower alkyl-lower alkenyltetrahydronaphthalene,

di (lower) alkyl-lower alkenyltetrahydronaphthalene,

tri (lower) alkyl-lower alkenyltetrahydronaphthalene,

di (lower) alkenyltetrahydronapthalene,

lower alkyl-di (lower) a]kenyltetrahydronaphthalene,

di(lower) alkyl-di (lower) alkenyltetrahydronaphthalene,

tri(lower) alkyl-di( lower alkenyltetrahydronaphthalene,

tri (lower) alkenylte trahydron aphthalene,

lower alkyl-tri (lower) alkenyltetrahydronaphthalene,

di (lower) alkyl-tri (lower) alkenyltetrahydronaphthalene,

tri (lower) alkyl-tri (lower) alkenyltetrahydronaphthalene,

lower alkenyldihydronaphthalene,

8 lower alkyl-lower alkenyldihydronaphthalene, di (lower) alkyl-lower alkenyldihydronaphthalene, tri (lower) alkyl-lower alkenyldihydronaphthalene, di (lower) alkenyldihydronaphthalene, lower alkyl-di (lower) alkenyldihydronaphthalene, di(lower) alkyl-di (lower) alkenyldihydronaphthalene, tri (lower) alkyl-di lower) alkenyldihydronaphthalene, tri( lo wer) alkenyldihydronaphthalene, lower alkyl-tri (lower) alkenyldihydronaphthalene, di (lower) alkyl-tri (lower) alkenyldihydronaphthalene, tri( lower) alkyl-tri (lower) alkenyldihydronaphthalene, etc.

The palladium oxyhydrate employed as the essential component of the catalyst in the present invention is known [Gmelin-Kraut: Handbuch der anorganischen Chemie, System Nr. -2, p. 257; Mellor: A Comprehensive Treatise Inorganic and Theoretical Chemistry, vol. 15, p. 656] and sometimes called palladium hydroxide [Kirk-Othmer: Encyclopedia of Chemical Technology, vol. 10, p. 842; Lange: Handbook of Chemistry, 9th ed., p. 282, No. 1514]. The palladium oxyhydrate may be prepared, for instance, by adding an alkali (e.g. sodium hydroxide, potassium hydroxide, barium hydroxide, calcium hydroxide, magnesium hydroxide, sodium carbonate, calcium carbonate, barium carbonate, magnesium oxide, calcium oxide) to a solution of a water-soluble palladium salt (e.g. palladium chloride, palladium nitrate, palladium sulfate, potassium palladium tetrachloride) in water. As the catalyst in the present invention, palladium oxyhydrate may be used alone but is preferred to use with a suitable supporting or diluting material such as asbestos, pumice, kieselguhr, activated carbon, alumina, boria, beryllia, magneisa, titania, zirconia, silica, silica-aluminum or any other similar material. The catalyst can be used in the form of fiber, granules, mechanically formed pellets or the like.

In order to form an oxygenic atmosphere, there may be used, for instance, oxygen gas, air, a mixture of oxygen gas with an inert gas such as nitrogen, carbon dioxide or steam or a compound which can generate oxygen on heating such as hydrogen peroxide or t-butylhydroperoxide. The molar ratio of oxygen to the non-aromatic cyclic hydrocarbon is preferably from 0.1:1.0 to 1011.0.

The oxidative dehydrogenation may be carried out over a wide range of temperature provided that it is in the range where palladium oxyhydrate used as the essential component of the catalyst can remain as such, usually at a temperature not exceeding about 600 C. (preferbly from about 50 to about 350 C., more preferably from about to about 300 C.), under an autogenous or a regulated pressure, ordinarily from about 0.01 to about 10 atm. (preferably from about 0.1 to about 5 atm.).

The liquid hourly space velocity, expressed by the liquid volume of the non-aromatic cyclic hydrocarbon charged per unit volume of the catalyst in unit time, may be preferably in the range of from about 0.1 to about 10 him- The method of this invention is ordinarily carried out by forming a mixture, preferably preheated, of the nonaromatic cyclic hydrocarbon to be dehydrogenated and oxygen or oxygen-containing stream and passing this mix ture over the catalyst at the desired temperature. Recycle of the unconverted hydrocarbon can be employed, if desired; however, the conversion rate and selectivity are excellently high to justify a single step operation (i.e. a single pass operation). The product stream can be generally used without separation steps in a subsequent operation such as polymerization.

The product in the oxidative dehydrogenation of this invention is the aromatic hydrocarbon retaining as such an unsaturated bond in a side chain, the unsaturated bond having been present in the starting non-aromatic cyclic hydrocarbon. Such aromatic hydrocarbon inc udes the one represented by either one of the following forwherein X is a substituted or unsubstituted monocyclic or 'bicyclic aromatic hydrocarbon group such as phenyl,

lower alkylphenyl (e.g. Z-methylphenyl, 2-ethylphenyl),

di(lower)a1kylphenyl (e.g. 2,4-dimethylphenyl, Z-methyl- 4-ethylphenyl) tri(lower)alkylphenyl (e.g. 2,4,6-trimethylphenyl, 2,4-

dimethyl-6-ethylphenyl) naphthyl,

lower alkylnaphthyl (e.g. Z-methylnaphthyl,

3 -methylnaphthyl) di(lower)alkylnaphthyl (e.g. 2,4-dimethylnaphthyl, 2-methyl-4-ethylnaphthyl) or tri(lower)alkylnaphthyl (e.g. 2,4,6-trimethylnaphthyl,

2,4,6-triethylnaphthyl) R R and R have respectively the same significance as R R and R and Y and m are each as defined above. Specific examples of the aromatic hydrocarbon are as follows:

lower alkenylbenzene (e.g. styrene, propenylbenzene,

isopropenylbenzene, allylbenzene) lower alkyl-lower alkenylbenzene (e.g. l-methyl-2- vinylbenzene, l-methyl-3-vinylbenzene, l-ethyl-3- vinylbenzene, 1-methyl-2-propenylbenzene, 1-ethyl-3- isopropenylbenzene, 1-methyl-4-allylbenzene, l-ethyl- 2-allylb enzene) di(lower)alkyl-lower alkenylbenzene (e.g. 1,2-dirnethyl- 3-vinylbenzene, 1,3-dimethyl-4-vinylbenzene, 1,2- diethyl-3-vinylbenzene, 1,2-dimethyl-3-propenylbenzene, l,4-dimethyl-2-isopropenylbenzene, 1,2-dimethyl-3-allylbenzene, 1-methyl-2-ethyl-4- allylbenzene tri(lower) alkyl-lower alkenylbenzene (e.g. 1,2,3-trimethyl-4-vinylbenzene, 1,2-dimethyl-3-ethyl-4-isopropenylbenzene) di(lower)alkenylbenzene (e.g. 1,2-divinylb6n2ene,

1,3-divinylbenzene, 1,2-dipropenylbenzene, 1,4- diisopropenylbenzene, 1,3-diallylbenzene),

lower alkyl-di(lower)alkenylbenzene (e.g. l-methyl- 2,3-divinylbenzene, 1-methyl-2,S-divinylbenzene, l-ethyl-2,4-divinylbenzene, l-methyl-2,4-dipropenylbenzene, 1-methyl-2,3-diisopropenylbenzene, l-ethyl- 2,4-diisopropenylbenzene, 1-methyl-3,S-diallylbenzene),

di(lower)alkyl-di(lower)alkenylbenzene (e.g. 1,2-

dimethyl-3,4-divinylbenzene, 1,2-diethyl-3,4-divinylbenzene, 1,3-dimethyl-2,S-diisopropenylbenzene,

1,2-dimethyl-3-vinyl-5-allylbenzene) tri lower) alkyl-di (lower) alkenylbenzene (e.g.

l,3,5-trimethyl-2,6-divinylbenzene,

1,3 -dimethyl-2-ethyl-4-vinyl-6-allylbenzene) tri(lower)alkenylbenzene (e.g. 1,3,5-trivinylbenzene,

1,3-divinyl-5-allylbenzene) lower alkyl-tri(1ower)alkenylbenzene (e.g. l-methyl- 2,4,6-trivinylbenzene,

1-ethyl-2,4, 6-triallylbenzene) di (lower) alkyl-tri (lower) alkenylbenzene (e. g.

1,3-dimethyl-2,4,6-trivinylbenzene,

l,3-diethyl-2,4,6-triallylbenzene) tri(lower)alkyl-tri(lower)alkenylbenzene (e.g. 1,3,5-

trimethyl-2,4,6-trivinylbenzene,

l,3-dimethyl-5-ethyl-2,4,6-trivinylbenzene) diphenyl(lower) alkene (e.g. stilbene, 1-phenyl-2- benzylethylene) phenyl-lower alkylphenyl(lower)alkene (e.g. l-phenyl- 2- (4-methylphenyl) ethylene,

l-phenyl-Z- 4-ethylphenylmethyl) ethylene) phenyl-di( lower) alkylphenyl( lower) alkene (e.g.

1-phenyl-2-(2,4-dimethylphenyl)ethylene,

l-ph'enyl-Z-(Z-methyl-4-ethylphenylmethyl ethylene) phenyl-tri (lower) alkylphenyl lower) alkene e. g. l-phenyl-Z- 2,4,6-trimethylphenyl )ethylene,

1-phenyl-2- (2,4,6-trimethylphenylmethyl) ethylene) lower alkylphenyl-lower alkylphenyl (lower) alkene e. g. l- 4-methylphenyl -2- 4-methylphenyl) ethylene,

1- Z-methylphenyl -2- (4-methylphenylmethyl) ethylene),

lower alkylphenyl-di (lower) alkylphenyl(lower) alkene e.g. l- (4-methylphenyl) -2- 2,4-dimethylphenyl) ethylene,

1- 2-ethylphenyl -2- 2-methyl-4-ethylphenyl ethylene,

lower alkylphenyl-tri (lower alkylphenyl (lower) alkene (e.g. 1- 2-methylphenyl) -2- 2,4,6-trimethylphenyl) ethylene,

l- 3-ethylphenyl -2- 2,4,6-trimethylphenylmethyl) ethylene) di (lower) alkylphenyl-(1i (lower alkylphenyl (lower) alkene e.g. 1- 2,4-dimethylphenyl) -2- 3,5 -dimethylphenyl ethylene,

1- 2,4-dimethylphenyl -2- 2,4-dimethylphenylrnethyl) ethylene) di (lower alkylphenyl-tri (lower) alkylphenyl (lower) alkene (e.g. 1-( 2,4-dimethylphenyl) -2- 2,4,6-trimethylphenyl) ethylene,

1- 2,4-dimethylphenyl -2- [2-( 2,4,6-trimethylphenyl) ethyl] ethylene) tri lower) alkylphenyl-tri( lower) alkylphenyl lower) alkene (e.g. 1- 2,4,6-trimethylphenyl -2- 2- (2,4,6-trimethylphenyl) ethyl] ethylene) lower alkenylnaphthalene e.g. l-vinylnaphthalene,

2-vinylnaphthalene) lower alkyl-lower alkenylnaphthalene (e. g. 2-1nethyll-vinylnaphthalene,

l-methyl-2-vinylnaphthalene) di (lower) alkyl-lower alkenylnaphthalene (e.g.

2,3 -dimethyll-vinylnaphthalene,

2-methyl-4-ethyl-l-vinylnaphthalene tri (lower) alkyl-lower alkenylnaphthalene (e. g.

2,3,4-trimethyll-vinylnaphthalene,

2,3 ,6-trimethyll-vinylnaphthalene) di( lower) alkenylnaphthalene (e.g. 1,2-divinylnaphthalene,

1-vinyl-3-allylnaphthalene) lower alkyl-di (lower) alkenylnaphthalene (e.g.

4-methyll ,2-divinylnaphthalene,

4-methyll -vinyl-3-allylnaphthalene) di( lower) alkyl-di( lower) alkenylnaphthalene (e.g.

3,4-dimethyll ,2-divinylnaphthalene,

3,4-diethyl-1,2-divinylnaphthalene) tri (lower) alkyl-di (lower) alkenylnaphthalene (e. g.

3 ,4,6-trimethyl-1,2-divinylnaphthalene,

3 ,4,6-trimethyll -vinyl-2-allylnaphthalene) tri (lower) alkenylnaphthalene (e. g. 1,2,3-trivinylnaphthalene,

1,2-diviny1-4-allylnaphthalene) lower alkyl tri (lower) alkenylnaphthalene e.g. S-methyl- 1,2,3-trivinylnaphthalene,

S-methyl-1,2-divinyl-4-allylnaphthalene) di (lower) alkyl-tri (lower) alkenylnaphthalene (e.g.

5,6-dirnethyl-l ,2,3-trivinylu-aphthalene,

5 ,6-di1nethyl- 1 ,2-divinyl-4-allylnaphthalene) tri (lower) alkyl-tri (lower) alkenylnaphthalene (e.g.

5,6,7-trimethyl-1,2,4-trivinylnaphthalene,

5,6-dimethyl-7-ethyl-1,2,4-trivinylnaphthalene) etc.

As well known, these aromatic hydrocarbons are useful as the starting monomers in the production of polymers such as plastics.

The oxidative dehydrogenation method of this invention is highly excellent in the conversion rate and selectivity so that the aromatic hydrocarbon having an ethylenically unsaturated bond in a side chain can be produced in an outstanding yield by single pass. Further, palladium oxyhydrate used as the essential component of the catalyst in this invention is sufficiently active even at a relatively low temperature, and the oxidative dehydrogenation can be accomplished avoiding unfavorable side reactions such as cracking, polymerization and combustion. The industrial and economical production of aromatic hydrocarbons having an unsaturated bond in 'a side chain is thus realized by the present invention.

Alflnough the oxidative dehydrogenation method of this invention is generally applicable to non-aromatic cyclic hydrocarbons having at least one unsaturated bond in a side chain, there are employed as the starting material ordinarily those being not more than 2,000, prefer= ably not more than 300 in molecular weight.

Practical and presently preferred embodiments of the present invention are shown'in the following examples.

EXAMPLE 1 mixtureis refluxed for minutes. The precipitate is collected by filtration, washed and dried to give the catalyst. V

A hard glass tube, 7 mm. in diameter, is packed with 0.36 g. of the catalyst above prepared. A gaseous mixture consisting of 1 part by weight of 4-vinylcyclohexene-1 and 3 parts by weight of oxygen is passed through the catalyst layer at a liquid hourly space velocity of 0.4 hr.- at a reaction temperature of 160 C. under an autogenous pressure. The conversion rate of 4-vinylcyclohexene-l in a single pass is 86.8%. The product consists of 91.3% by weight (selectivity) of styrene and 8.7% by weight of by=products. The total yield of styrene is 79.3%, based on the feed material.

For comparison, the reaction is carried out in the same manner as above but using as the catalyst a mixture of 1.0 g. of glass powder of 2 to 32 mesh and 100 g. of palladium black prepared by the Willst'atter method and setting the reaction temperature at 146 to 147 C. The conversion rate of 4-vinylcyclohexene-1 in a single pass 13%. The product consists of 96% by weight of styrene and 4% by weight of by-products. The total yield of styrene is 12.5%, based on the feed material.

EXAMPLE 2 EXAMPLES 3-10 The reaction is effected as in Example 1 but using a variety of feed materials. The results are set forth in the following table:

12 the non-aromatic cyclic hydrocarbon in the presence of oxygerfwith a catalyst consisting essentially of palladium oxyhydrate to "give the corresponding aromatic hydrocarbon retaining the said unsaturated bond.

2. The method according to claim 1, wherein the nonaromatic cyclic hydrocarbon is the one selected from the group consisting of the compounds of the formula:

wherein X is a substituted or unsubstituted monocyclic or bicyclic non-aromatic hydrocarbon group, R R and R are each a hydro-gen atom, a lower alkyl group, a cyclohexyl group, a lower alkylcyclohexyl group, a di(lower) alkylcyclohexyl group, a triglower)alkylcyclohexyl group, a cyclohexyl(lower)alkyl group, a lower alkylcyclohexyl (lower)alkyl group, a di(lower)alkylcyclchexylflower) alkyl group, a, tri(lower)alkylcyclohexylflower)alkyl ,group, a cyclohexenyl group, a lower alkylcyclohexenyl wherein Y is a lower alkylene group and X, R R R and m are each defined above.

3. The method according to claim 1, wherein the nonaromatic cyclic hydrocarbon is a lower alkenylcyclohexane.

4. The method according to claim .1, wherein the nonaromatic cyclic hydrocarbon is a lower alkenylcyclohexene.

5. The method according to claim 1, wherein the nonaromatic cyclic hydrocarbon is a lower allrenylcyclohexadiene.

6. The method according to claim 1, wherein the dehydrogenation is carried out at a temperature from about go about 350 C.

7.. The method according toclaim 1, wherein the molar ratio of oxygen to the non-aromatic cyclic hydrocarbon is from 0.1: 1.0 to 10: 1.0. W

8. The method according to claim 1, wherein the cat- Reaction ii Conversion a termperrate, Selectivity, 7 Feed material ature, C. Main product percent percent Example:

3 Virrylcyclohexane 160 Styrene 72 87 4. l-vinylcyclohexadiene-l.8. 16G do"; 89 92 5. 1,2-diviny1cyclohexene-3 160 1,2-divinylb enzene 87 81 6. 3-cyclohexyl-2-methyl-prope 160 3-phenyl-2-methyl-propenc-l 69 7 5- (3Eeyclohexenyl)-pentene-1 5-phenylpentene1; 82 89 8-- l-cyclohexyloctene-l 220 1-phenyloctene-1.-. i 100 72 9... 2-vmyl-1,2 dlhydronaphthalenenn Q-VinyI-naphtalene 98 73 10 l-phenyl-2-cyclohexylethylene. 240 Stilbene 100 69 What is claimed is: 1. A method for theoxidative dehydrogenation of a non-aromatic cyclic hydrocarbon having at least one unalyst consists of palladium oxyhydrate and asbestos.

9. In the selective dehydrogenation of a non-aromatic cyclic hydrocarbon selected from the group consisting of saturated bonds. in a side'chain which comprises contacting *75 lower alkenylcyclohexane, lower alkenylcyclohexene and lower alkenylcyclohexadiene to the corresponding lower alkenylbenzene, a method which comprises contacting the non-aromatic cyclic hydrocarbon in the, presence of oxygen with a catalyst consisting essentially of palladium oxyhydrate at a temperature from about 50 to about 350 C. under an autogenous pressure, the molar ratio of oxygen to the non-aromatic cyclic hydrocarbon being from 0.1:1.0 to 10:1.0.

14 References Cited UNITED STATES PATENTS 2,438,041 3/1948 Dutcher 260-669 3,153,101 10/1964 Konecky et a1 260-668 3,439,058 4/1969 Bailey et a1 260-669 DELBERT E. GANTZ, Primary Examiner