GB676370A - Recovery of procaine - Google Patents

Abstract

Procaine is separated from crude dilute aqueous solutions thereof by contacting the solution with activated carbon at pH below 8 (e.g. 2), separating the solution and washing the carbon with an acid of normality not greater than 2; procaine is recovered from the solution and the washings by increase of pH, e.g. to 10-12, when procaine base is precipitated, and may be separated in the solid form or extracted with a water-immiscible organic solvent, e.g. butyl acetate, and concentrated to effect precipitation or crystallization. The amount of carbon used is preferably about 1 per cent by weight of the solution, and may be in the form of a static mass, e.g. as a column. The acid used for washing may be hydrochloric or sulphuric; phosphoric is less suitable. The subsequent increase of pH may be effected with sodium hydroxide or other alkali. In a modification the solution, before or after the carbon treatment, is adjusted to pH greater than 8 and extracted with a water-immiscible solvent, e.g. amyl or butyl acetate, chloroform or ether; the procaine is then re-extracted with water at a pH below 6. The starting material may be the solution obtained in the production of sodium penicillin as in Specification 655,649. Examples are given of the various methods of carrying out the process of the invention. The filtrate and washings (containing procaine) may be used directly for the production of procaine penicillin.