CH416604A - Process for the preparation of arylcycloalkanes or alkyl-arylcycloalkanes - Google Patents

Description

       

  
 



  Process for the preparation of arylcycloalkanes or alkyl-arylcycloalkanes
The invention relates to the preparation of aryl cycloalkanes or alkyl-arylcycloalkanes from unsubstituted or alkyl-substituted aromatic hydrocarbons.



   As is known, cycloalkanes such as cyclohexane and decahydronaphthalene can be prepared from aromatic hydrocarbons such as benzene and naphthalene by hydrogenation with the aid of hydrogenation catalysts.



   It is also known that aromatic hydrocarbons can be obtained by adding ethylene or mixtures of ethylene and other hydrocarbons, e.g. B. propylene, heated under increased pressure in the presence of a heteropoly acid.



   The expression heteropoly acid is known to mean a complex acid composed of two or more polybasic oxygen-containing metal or non-metal acids.



   It has now been found that arylcycloalkanes or alkylarylcycloalkanes are obtained from unsubstituted or alkyl-substituted aromatic hydrocarbons by converting them in the liquid phase in the presence of hydrogen at a hydrogen pressure of less than 100 atm and a temperature of not above 2500 C with catalysts in Brings contact that has been obtained by combining a hydrogenation catalyst and a heteropolysacid.



   Examples of compounds obtainable according to the invention are: phenylcyclohexane from benzene toluylmethylcyclohexane from toluene diniethylphenyl <limethylcyclohexane from xylene naphthylhydronaphthalene from naphthalene phenylhydronaphthalene from benzene and naphthalene methylnaphthylmethylhydronaphthalene from methylnaphthylmethylhydronaphthalene from methylnaphthalene-naphthalene
For the implementation of the process according to the invention suitable heteropoly acids are, for. B.



  Silicotungstic acid, borotungstic acid, phosphotungstic acid, phosphotungstic acid, boromolybdic acid, silicomolybdic acid, phosphotungstic acid, arsenomolybdic acid, antimony tungstic acid.



   Important representatives of the hydrogenation catalysts are metals, e.g. B. nickel, cobalt, iron, platinum, palladium, iridium, osmium, rhodium and ruthenium, as well as oxides such. B. chromium oxide, molybdenum oxide and tungsten oxide, and also sulfide, z. B. molybdenum sulfide, nickel sulfide and tungsten sulfide.



   The amount of hydrogenation catalyst in the catalyst combination can be varied. Even with small amounts of hydrogenation catalyst of z. B. 0.1-2.5% by weight hydrogenation catalyst, based on the heteropolyacid, good results are achieved. Even larger amounts of z. B. 3, 5, 15 or 25% by weight of hydrogenation catalyst, based on the acid, can be used. A particular advantage is that it is possible to achieve a good yield of low-boiling arylcycloalkanes even with the very small amounts of the valuable hydrogenation catalysts mentioned.



   The combined catalyst can be on one
Be attached carrier. Examples of common carriers are: thoroxide, aluminum oxide, magnesium oxide, zirconium oxide, silicon dioxide, silica gel, kieselguhr or
Coal. Substances which are suitable as cracking catalysts for promoting the cracking of hydrocarbons to form liquid and / or gaseous products can also be used as carriers. Examples of such, as a carrier suitable cracking catalysts are: acidic metal silicates, which are composed of silicon dioxide and oxides of metals such as aluminum, calcium, zirconium and magnesium, while other inorganic oxides can also be present. Both sour
Clay as well as cracking catalysts mainly composed of silica come into consideration.



   The combination of the hydrogenation catalyst and the
Heteropolyacid can be achieved by intimate mixing.



   However, the desired combination can also be obtained in other ways, e.g. B. produces the hydrogenation catalyst in the presence of the acid. In this way, z. B. distribute a heteropoly acid in a solution of a compound of the metal of the hydrogenation catalyst and the hydrogenation catalyst can also be prepared after removal of the solvent.



   The method according to the invention can be carried out in the manner customary for a treatment with hydrogen.



   The temperature of not more than 250 C and the hydrogen pressure of less than 100 atm are chosen so that the reaction takes place in the liquid phase. There is no need to use pure hydrogen; inert gases such as nitrogen and saturated hydrocarbons can also be present. Furthermore, saturated hydrocarbons in the liquid phase, such as cyclohexane or decahydronaphthalene, can be added.



   example 1
The catalyst used in this embodiment consists - expressed in percent by weight - of 0.7 o / o platinum, 20 o / o silicon-tungstic acid and 79.3 o / o silica gel powder. This catalyst was obtained by impregnating silica gel with an aqueous solution of silicotungstic acid and platinum hydrochloric acid, then evaporating the water and then reducing the dry substance using hydrogen.



   In a 2 liter autoclave equipped with a stirrer, 3.5 g of the combined catalyst are distributed in 700 cm3 of benzene.



   Hydrogen is then passed into the autoclave and the reaction mixture is heated for 4 hours with stirring at a temperature of 1500 ° C. while the pressure is kept at 10 atm. After cooling to room temperature, the liquid reaction product is separated from the catalyst and distilled.



   The following is obtained: 16.3% phenylcyclohexane, 35.4/0
Cyclohexane, 36.0% benzene and 12.3% higher products.



   In a corresponding embodiment, in which, however, the temperature is 185-190 ° C. and the pressure is kept at 30 atm, 25.1 / o falls
Phenylcyclohexane, 12.7 O / o cyclohexane, 57.1 O / o benzene and 5.1 O / o higher-boiling products.



   Example 2
In a corresponding manner, as described in Example 1, 700 cm3 of toluene in the presence of
Treated 35 g of a catalyst which instead of platinum in this case contains 0.2 o / o palladium. The pressure is kept at 10 at and the temperature at 1500 C.



   After a reaction time of four hours, the following is obtained: 16.40 / 0 toluylmethylcyclohexane, 20.60 / 0 methylcyclohexane and 53% toluene and 10% higher dendX products.



   Example 3
Aluminum oxide is saturated with an aqueous solution of nickel nitrate and silicotungstic acid, then the water is evaporated and the dry substance is reduced. The catalyst obtained in this way is composed — expressed in percent by weight — of 10% nickel, 10% silicon woliramic acid and 89% aluminum oxide.



   With 35 g of this combined catalyst, in the same way as described in Example 1,
700 cm3 of benzene treated. The pressure is kept at 30 at and the temperature at 185-190 ° C.



   After a reaction time of four hours, 19.4% fall
Phenylcyclohexane, 5.2 o / o cyclohexane, 69.2 o / o benzene and 6.2 o / o of higher-boiling products.



   Example 4
The execution described in Example 3 is carried out again, but with the difference that in this case an aluminum silicate cracking catalyst (Al 2 O 3 content, old 13% by weight) is used as the carrier. The efficiency of the cracking catalyst is reduced beforehand by passing a mixture of 80% by volume of air and 20% by volume of steam over the cracking catalyst at a temperature of 8000 ° C. for two hours.



   After a reaction time of 8 hours there are now 30.4% phenylcyclohexane, 10.1% cyclohexane, 26.1% benzene, 27.8% dicyclohexylbenzene and 5.6% higher-boiling products (mainly Tricy elohexylbenzene).


    

Claims (1)

PATENT CLAIM Process for the production of arylcycloalkanes or alkyi-arylcydoalkanes from unsubstituted or alkyl-substituted aromatic hydrocarbons, characterized in that these hydrocarbons are in the liquid phase in the presence of hydrogen at a hydrogen pressure of below 100 at and a temperature of not above 2500 C with catalysts in Contact brought, which has been obtained by combining a hydrogenation catalyst and a heteropoly acid. SUBClaim Process according to claim, characterized in that the catalysts are used together with a carrier.