| abstract |
A protein hydrolysate is prepd. by alkaline hydrolysis from previously desalted, comminuted chrome tanned leather. This hydrolysate contains less than 1 ppm Cr, based on solids content. An excess quantity of a base is added for hydrolysis (calculated on Cr concn.) so that the initial concn. of 3.3-0.03 mol hydroxy-ion / cu.dm should yield pH 12.6-12.7 at completion of the reaction. The reaction mix is allowed to stand at room temp. for 3-48 hrs., followed by hydrolysis at 1-5 bar pressure and 70-150 deg.C for 0.1-10 hrs.. The Cr content of the hydrolysate is determined and once its min. value is reached, Cr hydroxide formed is removed instantly, at the prevailing reaction temp.. (1pp Dwg.No.0/0) |