Production of acetone by catalytic hydration of acetylene

Abstract

Among the known processes for the production of acetone, the most promising is the synthesis by hydration of acetylene in the presence of catalysts. The advantage of this method is the possibility of carrying out the process in existing acetaldehyde production plants. On the other hand, the process of simultaneous production of acetaldehyde and acetone under the action of polyfunctional catalysts and the implementation of the process using flexible technology is promising. To study the influence of various factors on the process of obtaining acetone by the catalytic hydration of acetylene and to create a technology for producing acetone. The specific surface area, crushing strength, total pore volume, and ash content of the samples were determined. Acetylene was saturated with water at a temperature of 70-80 ℃ and a ratio of water: and acetylene = (1:3)-(1:5), mol was passed through the catalyst bed at 360 ℃ with a space velocity of 180-200h-1. The gas-vapour mixture leaving the reactor was cooled in a refrigerator. The reaction products were collected with water. The catalyst contains acetaldehyde, acetone, crotonaldehyde, etc. To maintain the degree of acetylene conversion not lower than 80%, the reaction temperature was raised by 10 ℃ every 20 hours. After 96-120 hours, the degree of acetylene conversion decreases to 75-70%. The reactions of catalytic hydration of acetylene to acetaldehyde and acetone were carried out on the selection of polyfunctional mixed catalysts. As a result, a catalyst with cadmium fluoride and chromium(III) oxide dissolved in alumina promoted with aluminium fluoride was chosen to produce acetaldehyde. Acetaldehyde is formed by the interaction of acetylene: water =1:3–1:5 at 360-440 ℃ in the presence of a catalyst based on cadmium fluoride with a composition of 18% CdF2, 2,0% AlF3, 5% Cr2O3, 75% Al2O3. The addition of zinc oxide or fluoride to the cadmium-chromium-aluminium catalyst (Catalysts No.5) ensures the selectivity of the catalyst and directs the acetylene hydration reaction towards the formation of acetone. As the temperature rises above 450 ℃, the yield of acetone formation and the selectivity of the process decrease due to the transformation of the formed acetone into other substances. In the temperature range of 360-500 ℃, the relationship between the reaction yield and temperature is extreme, and at 450 ℃ the yield was considered to be maximum. Based on the obtained results, a technological scheme for the production of acetone by the catalytic hydration of acetylene was proposed.