GB799186A - A continuous process for catalytically alkylating aromatic hydrocarbons and alkylatable hydroxy derivatives thereof in the liquid phase by means of olefins - Google Patents

Abstract

An aromatic hydrocarbon or an alkylatable hydroxy derivative thereof such as phenol or resorcinol is alkylated with an olefin in a homogenous liquid phase reaction mixture comprising a silicate catalyst of natural or synthetic origin, containing in a combined form one or more of the metals Al, Mg and Zr. The olefin concentration in the reaction mixture is maintained below 1 mol. per cent and the olefin and hydrocarbon are continuously supplied in a molar ratio higher than that in the reaction mixture itself but not higher than the stoichiometric molar ratio involved in a predetermined degree of alkylation of the hydrocarbon. Hydrocarbons or hydroxy derivatives thereof containing 15-50 per cent aromatics, e.g. the mixtures obtained in the platforming (Registered Trade Mark) process, may be treated. The process may be used to prepare dialkyl benzenes from monoalkyl benzenes and an olefin, e.g. di-isopropyl benzene from cumene. The olefin referred to is propene; a mixture of olefins and saturated hydrocarbons, e.g. propane, may also be used. The process may be carried out at 150-320 DEG C. and 10-60 atm. pressure. The catalysts may also contain calcium, sodium and potassium silicates and, in combined form, hydrogen, carbon and sulphur together with oxygen, e.g. H2O, CO2 and SO3, and also traces of iron. The catalysts may contain, for example, 85-90 per cent by weight of SiO2 and 15-10 per cent of Al2O3. The catalyst, for example aluminium silicate, may be subjected before use to a surface-modifying treatment, e.g. by treatment with steam for 1-24 hours at 600 DEG C., or with hot air or inert gas at 800 DEG C.; or by treatment with aqueous HF solution. The process may be applied to the alkylation of cumene with propene to form di-isopropyl benzene, in which case to avoid polymerization of the propene, at least 50 per cent of the cumene, together with a small quantity of propene, may be pretreated with the catalyst; alternatively, pretreated cumene may be prepared by transalkylation of higher iso-propylated benzene derivatives or an isomerization of di-isopropyl benzene. Higher alkylated products of the alkylation reaction may be dealkylated or transalkylated; ortho and meta dialkyl benzenes formed may be isomerized; and undesired higher alkylation products may be recycled to the alkylation stage. Specification 504,614, [Group III], is referred to.