A process for the production of carboxylic acid esters

摘要

The invention comprises a process for the production of carboxylic acid esters, wherein the same limited quantity of one or more esterification catalysts in liquid form under the reaction conditions is continuously sprayed at high velocity within a reaction vessel to form a reaction zone which is filled by a layer of sprayed whirling particles of the liquid catalyst and is continuously recycled, while one or more carboxylic acids, anhydrides or esters is introduced into the reaction zone together with one or more alcohols, ethers or olefines. The catalyst may be a liquid, or a solution, suspension or emulsion of a catalyst material (which may itself be solid) in an inert liquid; specified catalysts are hydrochloric acid, sulphuric acid, phosphoric acid, aliphatic or aromatic sulphonic acids (the latter may be molten), and acid salts such as zinc chloride or aluminium chloride, which may contain water of crystallisation and may be used as aqueous or anhydrous melts or as solutions or suspensions; specified inert liquids are natural or synthetic paraffins, silicone oils and mineral oils. Suitable reactants are fatty acids such as formic, acetic, propionic, butyric, oleic, stearic, palmitic, and other saturated or unsaturated monocarboxylic acids, aromatic monocarboxylic acids such as benzoic and toluic acids, and dicarboxylic acids such as succinic, glutaric, adipic, suberic, azelaic, sebacic, phthalic, isophthalic and terephthalic acids; nonohydric alcohols and their ethers, polyhydric alcohols such as glycol and glycerol, and olefines such as ethylene, propylene and butylene. Examples prepare (1) ethyl acetate from acetic acid and ethanol; (2) propyl acetate from acetic acid and propylene; (3) ethyl acetate from acetic acid and ethanol; (4) methyl benzoate from benzoic acid and methanol; (5) isopropyl acetate from acetic acid and diisopropyl ether; (6) ethyl acetate from acetic acid and ether; (7) ethyl chloroacetate from chloroacetic acid and ethanol; (8) ethyl propionate from propionic acid and ethanol; and (9) ptoluic acid methyl ester from p-toluic acid and methanol. Some diisopropyl ether is formed in Example 2. Specifications 755,071 and 779,299 are referred to.ALSO: Forms of apparatus suitable for esterification processes with a liquid catalyst (see Group IV(b)) are as shown. A perforated rotor 3 (Fig. 1) or 9 (Fig. 2) fitted with blades or a propeller 8 draws up liquid catalyst 4 and discharges it as a spray through the perforations. Reactants enter by 5 and products leave by 6. Specifications 755,071 and 779,299 are referred to.