Determination of Saponification Number

Abstract

FIELD: assay of saponification number for tannery, paint-vehicle, etc. industry4 investigation of oils, fats, waxes, and various compositions thereof. ^ SUBSTANCE: saponification number is determined by alkaline hydrolysis of saponification substance sample such as vegetable oil, natural fat, mixtures or oxides thereof, or compositions containing the same with aqueous potassium hydroxide solution followed by titration of potassium hydroxide excess with hydrochloric acid in presence of indicator (e.g. phenolephthalein). Particularly saponification substance sample, ethyl cellosolve and aqueous potassium hydroxide solution are sequentially weighted in cylinder test tube. Then alkaline hydrolysis of saponification substance sample is carried out in the same test tube at room temperature with agitation using screw mixer at rate of 1650 rpm, for 3-10 min. Concentration of aqueous potassium hydroxide solution is 7.13-10.0 mol/kg; it's excess expressed in terms of calculated value is 18.9-44.0 %; and mass ratio of ethyl cellosolve and saponification substance sample is 1:2-1:1.5. Further some drops of phenolephthalein is introduced into test tube through special opening and titration with hydrochloric acid is carried out up to disappearance of phenolephthalein color. Saponification number is calculated according to the equation, described in the invention. ^ EFFECT: simplified method for determination of saponification number.