SU146737A1 - The method of obtaining furfural - Google Patents

Description

A known method for the production of furfural from synthetic solutions according to ed. St. No. 123527.

The proposed method differs from the known one in that the resulting hydrolysis is introduced in small doses into a boiling solution of 35-60 ° / o-th sulfuric acid.

This allows for better utilization of raw materials and increased product yield.

According to the proposed method, the raw material for the preparation of pentose is preliminarily subjected to hydrolysis. Then it is taken for further processing, and furfurol is obtained from the pentose hydrolyzate by introducing it in small portions into a boiling solution of 35-60 ° / about-th sulfuric acid.

When small porous xylose solution comes into contact with a sufficiently concentrated acid solution, a rapid saturation of the solution with furfural occurs, and their fumes along with water vapor pass into the reflux condenser and enter into the furfurol column to isolate pure furfurol. Together with furfural, organic acids are formed, and part of the pentose is transformed into a coal-like vein. 1, with acidic acid. This precipitate is a light solid powder that does not stick to the walls of the vessel. It is separated from the acid by filtration. Since furfural in this method is obtained from pure peitosis (with a low content of hexoses), the product of the product is more pure, almost does not contain unstable oxymethyl furfural.

Example. The reactor — a glass flask with a capacity of 5. g — is connected to a glass refrigerator. Droplet No. 146737, a funnel for feeding xylose solution, a funnel for feeding acid solution and a tube reaching the bottom of the flask and connected to a vacuum pump for extracting acid from the reaction vessel are introduced into the tube. The reaction vessel is heated by a hotplate.

150 ml of a 45 ° solution of the acid solution are introduced into the flask. The solution is heated to kiyeni and fed into it in a thin stream for 225 hours with 700 ml of xylose solution, containing 3.27 ° / o of sugar (in total, xylose consumes 22.92 g). Condensate consisting of a solution of furfural and organic acids flows out of the refrigerator. The volume of acid must remain constant, for which the volume of xylose solution supplied per unit of time must be equal to the volume of condensate removed.

As solids of the carbon-like substance accumulate in the acid, the acid from the flask is collected, filtered and again fed into the flask.

700 ml of condensate is obtained, in which 14.17 g of furfural is contained. The yield of furfural is 64% by weight of xylose, or 55.2% of theoretical. The process is continuous.

PRESENTS OF THE INVENTION

The method of obtaining furfural from pentose solutions according to ed. St. No. 123527, characterized by the fact that, in order to increase the yield of the product, the obtained gdrolizat is injected. By repeated doses into a boiling solution of 35-60% sulfuric acid.