SU825492A1 - Method of acetaldehyde production - Google Patents

Description

one

The invention relates to the preparation of acetaldehyde, which is widely used for the production of acetic acid, ethyl acetate, and n-butyl alcohol, which is an important solvent.

A method of producing acetaldehyde by oxidation of propylene with oxygen at 300-400 ° C and a pressure of 210 atm. Total propylene conversion to 44% l.

However, the method requires high oxidation temperatures and elevated pressure.

The closest in technical essence to the present invention is a method for producing acetaldehyde by oxidation of butenes-2 or a butene fraction enriched in butenes-2, with atmospheric oxygen. The oxidation is carried out in a flow reactor at atmospheric pressure and a temperature of 400-450 s in the presence of an aluminophosphorus catalyst with an atomic ratio of A1: P 1: 1-2: 3. Conversion of raw materials 25-40 mol. % 2.

The disadvantage of this method is the high oxidation temperature - 400450s, which requires high energy consumption.

The purpose of the invention is to reduce energy costs.

The goal is achieved by the fact that ethanol is subjected to oxidation in the presence of the catalyst Y-A 1, 5 at 1510 ° C, and the ozone-containing gas mixture serves as the oxidant (oL 0.723, 52).

The gas-vapor mixture of ethanol, obtained by bubbling a stream of gas (nitrogen, argon, oxygen, air), is oxidized in a flow reactor at atmospheric pressure and 15-100 ° C, with an optimum temperature of 15-60 ° C. The concentration of ethanol is from 1.5-10 to 2.5.10 4 mol / l, ozone - 1.5-6, mol / l. The ozone-containing mixture contains oxygen and nitrogen if ozone is obtained from air. Oxygen plays the role of a carrier and is not involved in the oxidation process. The oxidation is carried out in the presence of a catalyst.

The volumetric rate of the reaction mixture is 1000 h. Conversion of raw materials 26-64% with a selectivity of the process from 29-92%. The yield of the target product (acetaldehyde) is at the level of known methods.

Example. Catalyst (.0з fraction m, take fraction O, 16-0.63mm,

calcined under vacuum for 4 hours at 4.60 grams was loaded into the reactor and trained for 16 hours in a stream of ozone-containing mixture. The ethanol oxidation is carried out in a glass (Pyrex) perfect mixing reactor. Through | a vaporizer with ethanol at 0 ° C passes a stream of nitrogen at a rate of 85 ml / min and directs the treated gas-vapor mixture to the reactor. The ozone-containing mixture is fed there at a rate of 64 ml / min. The ethanol concentration in the reactor 2, mol / l, the ratio of ozone to ethanol g is 1.51. The reaction mixture is passed through a catalyst bed, the exhaust gases are condensed, and the reaction products are separated by a rectification method.

The table shows the results of the oxidation of ethanol with a catalyst ozone, 21 O in the gas phase with an ethanol concentration of 2.5-10 4 mol / l and a space velocity of the reaction mixture of 1000 h.

Claims (2)

It can be seen from the table that with a ratio of ozone to ethanol of 0.72: 3.52 and a temperature of 15–60 s, the highest selectivity is achieved. Thus, the proposed method allows the process temperature to be reduced to 15-100 ° C versus 400-450 in the known method. The invention The method of producing acetaldehyde by gas-phase oxidation in the presence of a catalyst is about that in order to reduce energy costs, ethyl alcohol is subjected to oxidation in the presence of a catalyst And Ij 0, and an ozone-containing gas mixture is used as an oxidizing agent (ot 0 , 72-3.52) At 15-100 ° C. Sources of information taken into account in the examination 1. USSR author's certificate number 483391, cl. C 07 C 47/06, 1975. 2. USSR author's certificate number 560871, cl. C 07 C 47/06, 1966 (prototype).