CS248059B1 - Production method of 2-furaldehyde from plant raw materials - Google Patents

Abstract

The principle of the production of 2-furaldehyde from The herbal raw material lies in the fact that a crushed feedstock having a particle size of 0.2 up to 5 mm are treated with chemical agents at 50 to 100 ° C for 0.5 to 3 hours single-stage and / or two-stage wherein in the first step, the chemical agent is use sulfuric acid or acid acetic acid in the form of an aqueous solution; \ tor. \ t a mixture of these acids in a ratio of 0.1 to 10% % sulfuric acid and 0.5 to 1.5 percent by weight. acetic acid at hydromodule 1: 1 to 1:10; it uses 20 to 96% as the chemical reagent sulfuric acid 0.5 to 7.0% weight by weight of original absolute dry raw material and raw material so treated is then exposed to a temperature of 160 ° C to 250 ° C in a vibrofluid reactor for a period of time 2 to 180 minutes, with the emerging product in the form of a vapor continuously from the reactor diverts.

Description

The invention relates to a process for the production of 2-furaldehyde from plant materials with a higher pentosan content, such as corn cobweed, soybean sticks, some deciduous trees by a direct process in a vibrofluidic layer.

The commonly used processes for the production of 2-furaldehyde from plant raw materials are predominantly one-stage, in which the pentosan hydrolysis and pentose dehydration are carried out in pressure equipment with the addition of a catalyst.

Methods for directly recovering 2-furaldehyde are directed in particular at the type, concentration and method of catalyst addition and the method of heating and continualizing the process.

Non-breaking methods of recovering 2-furaldehyde from pentosane solutions are widespread in the Soviet Union in particular. The pentosand hydrolyzate containing 3 to 4% of pentoses preheated to 90 to 100 ° C is mixed with a catalyst (sulfuric acid) into a dehydrator, where the reaction is carried out at a pressure of 10 atp.

The disadvantage of the process is the high steam consumption. Indirect non-pressures are based on catalyzed dehydration of pentose solutions on solid superheated particles in vibrating layer AO no. 210 733 or using hydrochloric acid as the catalyst at the boiling point of the reaction mixture - AO no. 218 738.

The essence of the process according to the invention consists in that the crushed raw material with a particle size of 0.2 to 5 mm is treated with chemical agents at a temperature of 50 to 100 ° C for 0.5 to 3 hours in a one-stage and / or two-stage process. In this step, sulfuric acid or acetic acid in the form of an aqueous solution or a mixture of these acids in a ratio of 0.1 to 10 wt. % sulfuric acid and 0.5 to 1.5 wt. of acetic acid in a hydromodule of 1: 1 to 1:10 and in the second stage, 20 to 96% sulfuric acid in an amount of 0.5 to 7.0% by weight of the dry absolute raw material is used as the chemical agent and the raw material so treated is then is subjected to a temperature of 160 to 250 ° C in a vibrofluidide reactor for 2 to 180 minutes, whereby the product formed is exposed to a temperature of 160 to 250 ° C. in the form of vapors continuously removed from the reactor.

Water vapor or other inert medium vapors may be passed through the reactor to rapidly remove 2-furaldehyde from the reaction zone. 2-Furaldehyde is further isolated from the vapor phase by conventional methods.

An advantage of the method according to the invention is that it can be carried out in a simple device, such as a continuous and non-pressurized process. 2-Furaldehyde is obtained from relatively concentrated vapors. The process is low on water consumption and is not associated with waste generation. The lignocellulosic residue that falls off in dry form has high combustion heat and provides energy coverage for the production of 2-furaldehyde. The process according to the invention does not form increments or inks. sediments that would jeopardize the operation of the production facility and reduce 2-furaldehyde yields.

The method according to the invention can be demonstrated by means of the following examples: Example 1

The corn cob is crushed in a hammer mill such that the grain size is less than 5 mm in diameter. The pulp was impregnated with 0.8% aqueous sulfuric acid in a 1: 1 hydromodule and heated at 95 ° C for 1 h. Then 2.5 percent by weight a is added. with. 70% H2SO4, which is sprayed evenly on the surface of the raw material in finely atomized form. The raw material so treated is exposed to heat in a vibrofluidic layer at 180-200 ° C for 30 min.

During heating, vapor is released through the vibrofluidic reactor, but only in such an amount that the total amount of water in the condensate does not exceed twice the weight of the dry raw material to be treated. The yield of 2-furaldehyde is 39.7% of the theoretical amount.

Example 2

Procedure as in Example 1, except that the pulp is impregnated with 1.5% aqueous acetic acid at 60 ° C for 3 hours. yield; 38.6%, Example 1 and d 3

Beech sawdust (0.2-0.5 mesh) is impregnated with an aqueous solution containing 0.1% H 2 SO 4 and 0.5% CH 3 COOH (hydromodule 1: 4) and heated to 85-95 ° C for 2h and then pre-dried so that their moisture content does not exceed 50% and is sprayed with an aqueous solution of 40% H2SO4 so that the quantity of sulfuric acid uniformly added to the sawdust surface does not exceed 3% by weight; with. raw materials.

The sawdust is heated in a vibrofluidic layer at 200 to 220 ° C for 30 minutes and during heating is passed through a chloroform vapor reactor such that the total amount of chloroform in the condensate does not exceed 100% by weight a. with. raw materials. The yield of 2-furaldehyde is 41% of theory.

Claims (1)

OBJECT OF THE INVENTION Process for the production of 2-furaldehyde from plant raw materials by a direct process in a vibrofluidic layer, characterized in that the crushed raw material with a particle size of 0.2 to 5 mm is treated with chemical agents at a temperature of 50 to 100 ° C for 0.5 to 3 hours in one step; In the first step, sulfuric acid or acetic acid in the form of an aqueous solution or a mixture of these acids in a ratio of 0.1 to 10% by weight is used as the chemical agent. % sulfuric acid and 0.5 to 1.5 wt. of acetic acid in a hydromodule of 1: 1 to 1:10 and in the second step, 20 to 96% sulfuric acid in an amount of 0.5 to 7.0% by weight are used as the chemical reagent. and the treated feedstock is then subjected to a temperature of 160 to 250 ° C in a vibrofluidic reactor for 2 to 180 minutes, leaving the resulting product in the form of vapors continuously removed from the reactor.