Acetalization of glycerine at presence of acid-modified clinoptilolite, bentonite and tripolite from the domestic deposits

Abstract

In recent years, the situation with glycerol (Gl) has changed dramatically due to rapid development of biodiesel industry, in production of which Gl is formed in large quantities. Cyclic acetals of Gl are used as additives to motor fuels, as well as intermediates in the synthesis of various mono derivatives of Gl, which are widely used in food and pharmaceutical industries, cosmetics, etc. On the examples of Gl interaction with acetone (Ac), benzaldehyde (BA) and formaldehyde (FA), authors revealed the prospects of nitric acid-modified samples of natural clinoptilolite (H-СPT), bentonite (H-BNT) and trepel (H-TRP) from Sokirnytsky, Dashukivsky and Konoplyansky deposits of Ukraine (respectively) as catalysts for Gl transformation into cyclic acetals. Factors that determine the optimal conditions for acid modification of raw material, providing maximum conversion of Gl and catalytic activity of obtained samples, have been identified. A characteristic feature of studied processes is need to change the reaction conditions when changing the carbonyl compound-partner of Gl. It was found that number of catalyst samples obtained on H-BNT basis, their activity is superior (or comparable) with cation exchange resin KU-2.