A process for the nuclear alkylation of aromatic compounds

摘要

The nuclear alkylation of aromatic compounds in the presence of liquid acid catalysts is effected by spraying the catalyst into a reaction zone to fill the zone with whirling liquid particles and the aromatic compound and alkylating agent are passed into the zone. As shown in Fig. 1, a pool of catalyst is maintained at the bottom of the reactor and is drawn up by a rotating cylinder 3 which preferably has a suction propeller attached and is sprayed out through holes in the cylinder. Reactants enter by pipe 5 and vaporous product leaves by pipe 6. If the product is liquid under the reaction conditions it accumulates in the pool of catalyst which may be continuously drawn off for recovery, catalyst being returned. Specified catalyst compositions are: (1) H3PO4- paraffin oil and optionally aqueous Na2HPO4; (2) ZnCl2-paraffin oil-water; (3) Cu-Zn-H3PO4; conventional single catalysts are also used.ALSO: The nuclear alkylation of aromatic compounds in the presence of one or more acid catalysts liquid under the reaction conditions is carried out by spraying the catalyst into a reaction zone to fill the zone with whirling liquid particles and the aromatic compound and the alkylating agent are passed into the reaction zone. Alkylatable aromatic compounds include hydrocarbons, amines and phenols and are preferably mononuclear. The alkylating agent may be a straight-chain branched or cyclic olefine of up to 6 carbon atoms, an alcohol up to 5 carbon atoms, an ether of an alcohol of up to 5 carbon atoms, an alkyl halide, preferably a chloride of up to 5 carbon atoms or an aromatic compound carrying several alkyl substituents. The catalyst may be an acid such as sulphuric, phosphoric or mono- or poly-functional aromatic or aliphatic sulphonic acid, such as benzene sulphonic acid and dimethyl sulphonic acid, used alone or in solution, suspension or emulsion in an inert dispersing agent liquid under the reaction conditions. Also suitable are acidly-reacting metal salts preferably used in solution or suspension such as anhydrous melts or concentrated aqueous solutions of zinc or aluminium chloride. Mixtures of these two types, e.g. phosphoric acid and zinc chloride, optionally with hydrogen chloride, can be used, and activators, preferably of large surface area, can be added, e.g. copper powder or metal salts such as zinc phosphate can be used to activate phosphoric acid. Suitable inert emulsifying or dispersing agents are natural or synthetic paraffins, mineral oils or silicone oils and suitable solvents include nitroparaffins. Friedel-Craft catalysts, e.g. anhydrous aluminium, zinc or ferric chloride, are used in solution or suspension in a nitroparaffin or paraffin. Temperatures of -10 DEG to 300 DEG C. are used according to the catalyst used, with pressures up to 50 atmospheres. The catalyst is preferably recycled within the reaction zone by using a cylindrical rotor 3, having holes in the surface, dipping into a pool of catalyst and preferably having a suction propeller attached thereby drawing up the liquid inside the cylinder and spraying it out through the holes. The catalyst then runs down the walls to the pool. Preferably the speed of spraying is at least 2 litres per litre of reactor space per hour. Where the products are vaporized at the reaction temperature the reactants are introduced at the bottom of the zone by pipe 5 and passed upwardly through the sprayed catalyst and the products removed at the top through pipe 6 and recovered from unreacted material by fractional condensation. Where the products are liquid and collect in the catalyst, liquid is continuously withdrawn, product separated and catalyst returned to the reaction zone. The reactants may be passed through several zones in series.