GB830886A - Improvements in or relating to the preparation of carboxylic compounds - Google Patents

Abstract

A process for the preparation of propionic acid or salts thereof comprises contacting an alkali metal or alkaline earth metal salt of o-cresol with at least one of hydrogen, cycloaliphatic hydrocarbons, alkali metal hydrides and alkali metal borohydrides at elevated temperature and pressure and thereafter recovering the propionic acid or salts thereof so formed. Cycloaliphatic hydrocarbons mentioned include cyclohexane, methyl and ethyl cyclohexanes, 1,2-dimethyl-cyclohexane, cyclopentane, tetra- and decahydronaphthalenes. Phenol is produced simultaneously. Mixtures of phenols containing o-cresol, e.g. cresylic acid containing a - and b -methyl naphthalenes may be employed as starting materials. The o-cresol, optionally with other phenols, may be neutralized with, e.g., alkali metal hydroxides or alkaline earth metal oxides or hydroxides. An alkali is preferably added to the reaction mixture in excess. Alkali metal carbonates are also stated to be suitable for use in the process. The free propionic acid and phenol may be obtained by treating the reacted mixture with acidic material, e.g. sulphonic or hydrochloric acid, carbon or sulphur dioxide. The reactant melt may be anhydrous or may contain some water. The propionic acid may be recovered in the form of the sodium, potassium, ammonium, barium or calcium salt. Examples are furnished.