United States Patent (19) - (11) 4,178,317 A. Horn et al. 45 Dec. 11, 1979 54 MANUFACTURE OF OLEFINICALLY (56) References Cited UNSATURATED ALPHATIC OR CYCLOALIPHATIC HYDROCARBONS U.S. PATENT DDOCUME MENT S 4,024,171 5/1977 McArthur ....................... 260/666A 75) Inventors: Peter Horn, Hirschberg; Otto-Alfred FOREIGN PATENT DOCUMENTS Grosskinsky; Hugo Fuchs, both of Ludwigshafen, all of Fed. Rep. of 943745 12/1963 United Kingdom. Germany Primary Examiner-Veronica O'Keefe w Attorney, Agent, or Firm-Keil & Witherspoon 73) Assignee: BSAngelschall, Fed. Rep. 57 ABSTRACT Olefinically unsaturated aliphatic or cycloaliphatic hy 21) Appl. No.: 907,678 drocarbons are manufactured by bringing alkanecar boxylic acids of 3 to 20 carbon atoms, alkanedicarboxy ilar. lic acids of 4 to 20 carbon atoms or 5-membered or (22) Filed: May 19, 1978 6-membered cycloalkanecarboxylic acids or their alkyl, O 9 cycloalkyl, aralkyl or phenyl esters, in the gas phase, at 30. Foreign Application Priority Data from 250 to 800 C., into contact with catalysts in Jun. 10, 1977 (DE) Fed. Rep. of Germany. 2726106 which the active composition consists of boron trioxide, boric acid and/or boron nitride, together with one or 51) Int. C.’................................................ C07C3/00 more of the oxides of aluminum, silicon, tin, lead, tita 52 U.S. C. .................................... 585/357; 585/638; nium and zirconium. 585/640 (58) Field of Search .................................... 260/666 A 9 Claims, No Drawings 4,178,317 1. 2 ahydrobenzoate, cyclohexyl hexahydrobenzoate, MANUFACTURE OF OLEFINICALLY phenyl hexahydrobenzoate and benzyl hexahydroben UNSATURATED ALPHATIC OR ZOate. : .. 8 CYCLOALPHATIC HYDROCARBONS Of course the decarbonylation of monocarboxylic acids or their esters gives monoolefinically unsaturated The present invention relates to a process for the compounds with one carbon atom fewer, whilst the manufacture of olefinically unsaturated aliphatic or decarbonylation of dicarboxylic acids gives diolefins cycloaliphatic hydrocarbons by heating alkanecarboxy with 2 carbon atoms fewer. lic acids of 3 to 20 carbon atoms, alkanedicarboxylic The reaction is carried out in the gas phase. Advanta acids of 4 to 20 carbon atoms or 5-membered or 6-men 10 geously, the carboxylic acids, or their esters, used as bered cycloalkanecarboxylic acids or the alkyl, cycloal starting materials, are vaporized, but inert gases, such as kyl, aralkyl or phenyl esters of these at from 250 to nitrogen, noble gases, carbon dioxide, carbon monox 800 C. in the gas phase in the presence of a catalyst. ide, steam or flue gases may additionally be employed in There is a frequent requirement to convert carboxylic order to facilitate using the starting materials in the gas acids, obtained, for example, by oxidation processes, or 15 phase. The amount of such inert gas used is not critical, to convert carboxylic acids or their esters, obtained as since the gas merely serves as a carrier gas. by-products of carbonylation processes, into the corre The reaction is advantageously carried out under sponding olefins by decarbonylation. The decarbonyla atmospheric pressure, slightly superatmospheric pres tion of carboxylic acids of their esters is of particular sure, or reduced pressure, for example down to 20 mm interest if it permits olefins which are not readily acces 20 Hg. A pressure range from atmospheric pressure to 100 sible to be obtained from the more easily accessible mm Hg has proved particularly suitable. carboxylic acids or their esters. The reaction takes place at from 250 to 800. C., It is true that German Published Application DAS advantageously from 250 to 700° C. No. 1,158,050 has disclosed that carboxylic acids can be The reaction is carried out in the presence of cata converted into acid anhydrides and/or ketones by heat 25 lysts, of which the active composition consists of boron ing at from 250 to 800° C. in the gas phase in the pres trioxide, boric acid and/or boron nitride, together with ence of a catalyst comprising oxides, hydroxides and one or more of the oxides of aluminum, silicon, lead, phosphates of main groups 2 to 4 and sub-groups 3 to 8 titanium or zirconium. Preferred active compositions of the periodic table. However, the corresponding ole contain from 10 to 60, especially from 20 to 55, 7% by fins cannot be obtained by this method. 30 weight of boron trioxide, boric acid and/or boron ni It is an object of the present invention to provide a tride. The remainder of the active composition then process by means of which carboxylic acids or their consists of one of the above oxides. Active compositions esters can be converted by decarbonylation into the which contain boron trioxide or boric acid, especially corresponding olefins. the former, have proved particularly suitable. We have found that this object is achieved by a pro 35 The preferredoxides also present in the active com cess for the manufacture of olefinically unsaturated positions include alumina, e.g. in the form of hydrargil aliphatic or cycloaliphatic hydrocarbons by heating lite, boehmite or bayerite and their dehydration prod alkanecarboxylic acids of 3 to 20 carbon atoms, al ucts, e.g. y-, e- or 8-alumina, as well as tin dioxide, kanedicarboxylic acids of 4 to 20 carbon atoms or 5 titanium dioxide and silica gel. The use of alumina, or of membered or 6-membered cycloalkanecarboxylic acids 40 titanium dioxide in the anatase modification, is pre or their alkyl, cycloalkyl, aralkyl or phenyl esters at ferred. a-Alumina is industrially of particular impor from 250 to 800° C. in the gas phase in the presence of tance since it reduces the isomerization of the olefini a catalyst whereof the active composition consists of cally unsaturated hydrocarbons formed. baron trioxide, boric acid and/or boron nitride together Further catalysts according to the invention are those with one or more of the oxides of aluminum, silicon, tin, 45 resulting from mixed phase formation between one of lead, titanium or zirconium. the boron compounds used and the oxides mentioned The new process has the advantage that carboxylic above, e.g. boron trioxide and alumina, giving com acids or their esters can be converted in a simple manner pounds of the empirical formula 9 Al2O3. 2 B2O3 or 2 into olefins. It has the further advantage that it is easily Al2O3. B2O3. In such mixed phases, alumina is no scaled up to industrial operation and runs with good 50 longer detectable by X-ray crystallography. yields and good conversions. Advantageously, the active compositions addition It is preferred to start from an alkanecarboxylic acid ally contain one or more of the elements of group VIII of 3 to 16 carbon atoms, an alkanedicarboxylic acid of 4 of the periodic table, manganese, chromium, copper, to 12 carbon atoms or cyclohexanecarboxylic acid. zinc, cadmium, silver and/or gold. The said elements. Their alkyl, cycloalkyl, aralkyl and phenyl esters, espe 55 are preferably present in the active composition in an cially their alkyl esters, where alkyl is of 1 to 8 carbon amount of from 0.1 to 10% by weight (calculated as atoms, their cyclohexyl esters, their benzyl esters and metal), based on the active composition. their phenyl esters, are also suitable. The use of the free Suitable catalysts are prepared by, for example, mix carboxylic acids or of the corresponding methyl esters ing alumina and boron oxide or boric acid, or com as starting materials is preferred. The new process is of 60 pounds which form these on heating, e.g. ammonium particular industrial importance for the manufacture of borate, with or without the addition of compounds of cyclohexene from hexahydrobenzoic acid or its esters. the above heavy metals, e.g. manganese nitrate, manga Specific examples of suitable starting materials are pro nese acetate, cobalt nitrate, cobalt acetate, nickel ni pionic acid, methyl propionate, isobutyric acid, butyl trate, rhodium chloride, tris-(triphenylphosphine)- isobutyrate, caproic acid, methyl caproate, decanecar 65 rhodium chloride, iridium chloride, palladium nitrate, boxylic acid, palmitic acid, methyl palmitate, dimethyl platinum chloride, zinc nitrate, cadmium nitrate, copper adipate, dimethyl methylglutarate, methyl cyclopen nitrate, silver nitrate or gold chloride, if appropriate tanecarboxylate, hexahydrobenzoic acid, methylhex working the mixture into a paste with water and knead 4, 178,317 3 4. ing the paste, and molding the material into shapes, e.g. pills, tablets or extrudates. Advantageously, the mate EXAMPLE 1. rial is then dried and heated at up to 400 C. If the active 200 g of hexahydrobenzoic acid per hour were passed composition is to be used as a fluidized bed catalyst, it is from a vaporizer into a fluidized bed reactor at 550 C., advisable to comminute the moldings to the desired 5 the reactor being charged with 630g of a catalyst which size, e.g. to an average particle size of from 0.01 to 2 consisted of 52.3 percent by weight of y-Al2O3 and 45.5 mm, especially from 0.2 to 1 mm. The catalyst composi percent by weight of B2O3, and had a particle size of tion is then heated at from 600 to 1,500 C., preferably from 0.1 to 0.3 mm and a bulk density of 0.63 kg per from 700 to 1,300° C. and especially from 1,000 to liter. The catalyst was fluidized by means of the hexahy 1,200 C. for a period of from 15 minutes to 20 hours, O drobenzoic acid vapor and a slight stream of nitrogen, especially from 30 minutes to 5 hours. as well as by maintaining a reduced pressure of 360 mm In another advantageous embodiment, the active Hg. The resulting reaction vapors were condensed. The compositions according to the invention are obtained following products were isolated after 3 hours' opera by impregnating, for example, alumina or one of the tion: 86 g of water and 384 g of an organic phase.