GB213493A - - Google Patents

Abstract

213,493. Moeller, W. May 1, 1923, [Convention date]. Extracts, making and treating. - Crude solid extracts, particularly quebracho extract, are converted into easily soluble solid extracts by heating with appropriate reagents, without addition of water for forming a solution, to a temperature at least sufficient to cause fusion of the extract. Suitable reagents are sodium sulphite, sodium bisulphite, sodium carbonate and bisulphite, synthetic tanstuffs, sulphite cellulose extract, and sulphonic acids of hydrocarbons and phenols or their condensation products, with or without addition of an aldehyde or ketone. In an example 100 kg. of crude solid quebracho extract are finely ground with ¢ kg. of calcined sodium carbonate and 3 kg. of sodium bisulphite. The mixture is cautiously heated to 60‹ C., with stirring, in a closed vessel, and the temperature is then gradually raised to 100‹ C.; if the crude extract contains phlobaphenes the temperature may be further raised to 120 - - 130‹ C. with application of pressure. The operation lasts 2-3 hours, and the product is withdrawn at a temperature of 80‹ C. into sacks, where it is allowed to solidify. Decolourizing agents may be added to the original mixture, and water may also be added to make good the loss due to heating.