GB363788A - Improvements in a process for producing formates of alkaline earth metals - Google Patents

Abstract

Alkaline-earth formates, including magnesium formate, are obtained by the action of carbon monoxide or gases containing carbon monoxide on alkaline-earth metal hydroxides at elevated temperatures and super-atmospheric pressure, in the presence of not more than about 30 parts, and preferably between 10 and 20 parts of alkali metal formates to every 100 parts by weight of alkaline-earth hydroxide. The alkali formate may be formed in situ by adding suitable parent substances to the reaction mass originally; examples of such substances are caustic alkalis, alkali phenolates, acetates, oleates, chromates, carbonates, sulphides, sulphates, alcoholates, ferrocyanides, and borates. Potassium salts are preferable to sodium salts. The reaction may be effected in the presence of large amounts of water, sufficient alkaline-earth metal formate being added to the reaction mixture to form a saturated solution, so that the formate produced by the reaction is precipitated, the mother liquor being used again. Alternatively, the alkaline-earth metal hydroxide may be treated in the solid, preferably finely powdered form, in the presence of small quantities of moisture, which may be supplied to the reaction as water vapour. Calcium hydroxide may be obtained in a suitable form as a loose powder by slaking lime in a current of steam, and in this case the heat of hydration can be utilized for the reaction with carbon monoxide. The product consisting of alkaline-earth formate mixed with alkali formate is especially suitable for working up into formic acid by treatment with sulphuric acid. Examples are given.