Europäisches Patentamt *EP000985649A2* (19) European Patent Office Office européen des brevets (11) EP 0 985 649 A2 (12) EUROPEAN PATENT APPLICATION (43) Date of publication: (51) Int Cl.7: C07C 5/27 15.03.2000 Bulletin 2000/11 (21) Application number: 99307167.9 (22) Date of filing: 09.09.1999 (84) Designated Contracting States: • Minomiya, Eiichi AT BE CH CY DE DK ES FI FR GB GR IE IT LI LU Okazaki-shi, Aichi 444-3505 (JP) MC NL PT SE • Inohara, Masahiro Designated Extension States: Mizuho-ku, Nagoya-shi, Aichi 467-0042 (JP) AL LT LV MK RO SI • Iwayama, Kazuyoshi Nagoya-shi, Aichi 464-0074 (JP) (30) Priority: 09.09.1998 JP 25509898 • Kato, Testuya 19.11.1998 JP 32994498 Kamakura-shi, Kanagawa 248-0032 (JP) (71) Applicant: TORAY INDUSTRIES, INC. (74) Representative: Coleiro, Raymond et al Tokyo 103-8666 (JP) MEWBURN ELLIS York House (72) Inventors: 23 Kingsway • Nakatani, Jiro London WC2B 6HP (GB) Nagoya-shi, Aichi 458-0044 (JP) (54) Method for producing an aromatic compound having an alkyl group with at least three carbon atoms (57) Aromatic compounds having an alkyl group alyst containing zeolite and containing rhenium with at least 3 carbon atoms are produced in a process and/or silver, in a liquid phase, thereby changing the comprising at least one of the following steps: position of the carbon atoms of the alkyl group bonding to the aromatic ring of the compound; (1) a step of contacting a starting material that con- (3) a step of contacting a halogenated aromatic tains an aromatic compound having a branched compound having an alkyl group with at least 3 car- alkyl group with at least 3 carbon atoms, with a ze- bon atoms, with an acid-type catalyst, thereby olite-containing catalyst in a liquid phase in the isomerizing the compound; and presence of hydrogen therein, thereby changing the (4) a step of treating a mixture of isomers of an ar- position of the carbon atoms of the alkyl group omatic compound having an alkyl group with at bonding to the aromatic ring of the compound; least 3 carbon atoms, with a zeolite adsorbent that (2) a step of contacting a starting material that con- contains at least one exchangable cation selected tains an aromatic compound having a branched from alkali metals, alkaline earth metals, lead, thal- alkyl group with at least 3 carbon atoms, with a cat- lium and silver, thereby separating a specific isomer from the isomer mixture through adsorption. EP 0 985 649 A2 Printed by Jouve, 75001 PARIS (FR) EP 0 985 649 A2 Description [0001] The present invention relates to a method for producing of aromatic compounds having an alkyl group with at least 3 carbon atoms, which are useful as starting materials for production of various pharmaceuticals and agricultural 5 chemicals, through conversion, isomerization and/or adsorptive separation of aromatic compounds, and also to cata- lysts and adsorbents for the method. [0002] In aromatic compounds having a branched alkyl group with at least 3 carbon atoms, in general, it is difficult to change the position of the carbon atoms of the alkyl group bonding to the aromatic ring. Especially, (A) reducing the number of the branches of the alkyl group, (B) shortening the branched side chains of the alkyl group and (C) changing 10 the alkyl group into a different one bonding to the aromatic ring via a secondary carbon are difficult. [0003] One example of changing the position of the carbon atoms of an alkyl group bonding to an aromatic ring, thereby reducing the number of the branches of the alkyl group is represented by the following chemical reaction formula: 15 20 25 wherein R1 to R5 each represents a methyl, an ethyl group, or a linear alkyl group with at least 3 carbon atoms; 30 X1 and X2 each represent a methyl group, an ethyl group, a halogen atom, a formyl group, a carboxyl group, an alkoxy group, a nitro group, an amino group, or a cyano group; n is from 0 to 5. [0004] Another example of changing the position of the carbon atoms of an alkyl group bonding to an aromatic ring, 35 thereby shortening the branched side chains of the alkyl group is represented by the following chemical reaction for- mula: 40 45 50 wherein R6 represents an ethyl group, or a linear alkyl group with at least 3 carbon atoms; R8 represents a hydrogen atom, or an alkyl group of which the carbon chain is shorter than that of R6; R7 and R9 each represents an alkyl group; X3 and X4 each represent a methyl group, an ethyl group, a halogen atom, a formyl group, a carboxyl group, an alkoxy group, a nitro group, an amino group, or a cyano group; 55 n is from 0 to 5. [0005] Still another example of changing the position of the carbon atoms of an alkyl group bonding to an aromatic ring, thereby changing the alkyl group into a different one bonding to the aromatic ring via a secondary carbon is 2 EP 0 985 649 A2 represented by the following chemical reaction formula: 5 10 15 wherein R10 to R12 each represents an alkyl group; X5 and X6 each represent a methyl group, an ethyl group, a halogen atom, a formyl group, a carboxyl group, an alkoxy group, a nitro group, an amino group, or a cyano group; n is from 0 to 5. 20 [0006] Specifically, alkylating benzene with propylene gives a main product of isopropylbenzene in which the branched alkyl group directly bonds to the aromatic ring via its tertiary carbon, but gives a minor side product of n- propylbenzene in which the non-branched alkyl group directly bonds to the aromatic ring via its secondary carbon. In the main product of isopropylbenzene, the isopropyl group is stabilized. In this, therefore, it is difficult to change the configuration of the alkyl group bonding to the aromatic ring so as to change the isopropylbenzene into n-propylben- 25 zene. The same shall apply to any other aromatic compounds having a higher alkyl group. Anyhow, it is known that alkyl group-substituted aromatic compounds, in which the number of the branches of the alkyl group is small and/or the branched side chains of the alkyl group are short and/or the alkyl group bonds to the aromatic group via a secondary carbon, are difficult to produce. Therefore, in order to obtain n-alkyl group-substituted aromatic compounds, generally employed is a method of alkylating aromatic compounds with an n-alkyl halide or an n-alkyl alcohol. However, the 30 method is not always satisfactory in industrial use, since the reagents to be used are expensive and since the n-alkyl group-substituted aromatic compounds produced are partly isomerized. Another method is known, which comprises alkylating toluene with ethylene in the presence of an alkali catalyst, but this is still unsatisfactory in industrial use. Given that situation, it is desired to develop efficient and inexpensive methods for producing n-alkyl group-substituted aromatic conpounds. 35 [0007] Japanese Patent Laid-Open No. 141525/1984 discloses an inexpensive method of producing benzene com- pounds having an n-alkyl group from inexpensive starting materials. In the method, an alkylbenzene having a branched alkyl group, of which the number of carbon atoms is the same as that of carbon atoms of the n-alkyl group in the intended product, is contacted with zeolite catalyst along with a benzene derivative. Journal of Catalysis, Vol. 146, pp. 523-529, 1994, and Applied Catalysis A, Vol. 108, pp. 187-204, 1994 disclose vapor-phase alkylation of toluene with 40 isopropanol and propanol in the presence of a zeolite catalyst, in which the initial-stage product of methylisopropyl- benzene is trans-alkylated with the starting toluene or benzene into n-alkylbenzenes. [0008] Halogenated aromatic compounds having an alkyl group with at least 3 carbon atoms are produced from aromatic compounds having an alkyl group with at least 3 carbon atoms through nucleophilic substitution with halogens such as chlorine and bromine. The halogenation is extremely specific to ortho (o-) and para (p-) orientation. Therefore, 45 for obtaining meta (m-) isomer through the reaction, the product must be isomerized. The ratio of isomers of halogenated aromatic compounds having an alkyl group with at least 3 carbon atoms that are demanded in the market often differs from that of those isomers that are actually produced through halogenation. Therefore, for effectively utilizing halogen- ated aromatic compounds having an alkyl group with at least 3 carbon atoms, the isomerization of the compounds has an important technical meaning. Specifically, the isomerization referred to herein is to change the relative position of 50 the halogen and the alkyl group on the aromatic ring of halogenated aromatic compounds, and does not include isomer- ization of the alkyl group itself. As conventional examples of isomerization of aromatic compounds, generally known are a method of using a catalyst of aluminium trichloride or the like such as that disclosed in J. Org. Chem., Vol. 27, p. 3464, 1962; and a method of using a catalyst of HF-BF3 such as that disclosed in Japanese Patent Laid-Open No. 11809/1971. Apart from those, Acta Chemica Scandinavia, Vol. B39, p. 437, 1985, and Japanese Patent Laid-Open 55 No. 316600/1998 disclose isomerization of chloroethylbenzene with mordenite-type zeolite. Japanese Patent Laid- Open Nos. 4042ε/1982, 85330/1982, 163327/1982 and 309792/1995 disclose isomerization of halogenotoluenes with a catalyst of zeolite. [0009] A compound having a higher alkyl group shall include isomers, depending on the number of the branches of 3 EP 0 985 649 A2 the alkyl group therein, and the isomers generally have similar properties (boiling point, melting point, solubility).