Method for producing 2-butenoic acid

Abstract

The invention provides a method for producing 2-butenoic acid, which comprises the following steps: preparing mixed feed liquid from 2-butenoic aldehyde, normal hexane and water in a weight ratio of 1:1:0.05-0.08; mounting an ejector pump on an oxidation reaction kettle for spraying the mixed feed liquid into the oxidation reaction kettle; introducing oxygen into the oxidation reaction kettle to perform a reaction under a condition that the reaction pressure in the oxidation reaction kettle is 0.1 to 0.6MPa and a condition that the temperature is 25 to 35 DEG C to obtain oxidation reaction solution; distilling the oxidation reaction, distilling the remaining 2-butenoic aldehyde under a reduced pressure, recovering the 2-butenoic aldehyde, distilling the remaining normal hexane at normal pressure and obtaining filtrate; and cooling the filtrate to -5 DEG C to 5 DEG C, precipitating, crystallizing and filtering and drying the crystals to obtain the 2-butenoic acid product. The production method has the advantages that: the reaction speed is high; the product yield is high; the energy consumption is small; and the quality of the product obtained is high.

Description

technical field [0001] The invention relates to a production method of 2-butenoic acid, belonging to the technical field of chemical production. Background technique [0002] The trade name of 2-butenoic acid is crotonic acid, its English name is Crotonic acid Butenoic acid, and its chemical structure is CH 3 CH=CHCOOH, the molecular formula is C 4 h 6 o 2 , the molecular weight is 86.09, its physical and chemical properties: white crystal, with suffocating odor; It is 185°C, soluble in water, alcohol, acetone, toluene, ether and other solvents. It is irritating to skin and eyes. It can be used in synthetic resins, fungicides, surface coatings, plasticizers, rubber softeners, hot melt adhesive. [0003] According to reports, the industrial preparation of 2-butenoic acid is made from 2-butenal as a raw material through oxidation. During the reaction, 2-butenal is oxidized into a peroxy 2-butenoic acid intermediate, and then generates 2-butenoic acid. [0004] On the ox...

AI Technical Summary

Problems solved by technology

The above studies have shown that by adding catalysts such as precious metals, metal acetates, and silver nitrate, the reaction speed can be accelerated, the reaction time can be shortened, and the yield per unit time can be increased, but the products contain a certain amount of metal impurities, and the quality cannot reach that of European and American Market requirements, so it is not suitable for industrial promotion

[0005] On the other hand, crotonaldehyde is directly oxidized to 2-butenoic acid without using any catalyst, but the catalytic reaction time is long and the product quality is not high; for example, hochst oxidizes crotonaldehyde with pure oxygen, the reaction temperature is 30-35°C, and the oxidation takes three days Obtain 2-butenoic acid with a yield of 55%; later, the German huils plant once oxidized in the air under 3 to 5 atmospheres to obtain dark brown 2-butenoic acid with a yield of 75%. The reaction time of this method is Long, poor chroma, large energy consumption, low yield, difficult to promote industrialization; the United States Eastman Kodak Company uses a certain concentration of oxygen-containing gas, and adds a diluent to oxidize under a pressure of 0.34-0.68Mpa. Obtain white 2-butenoic acid, the content is above 98%, and the yield can reach 85%-91%

[0006] Summarizing the above methods, the use of catalysts for the oxidation of crotonaldehyde requires the consumption of precious metal oxides, or the use of very unsafe peroxides, which has the disadvantages of high production costs, harsh reaction conditions, complicated post-treatment processes, and low yields. , so it is not suitable for industrial production; and the non-catalyzed oxidation reaction of crotonaldehyde, although the cost is low, its reaction cycle is long, the yield is low, energy consumption is large, the product quality is low, and it is difficult to carry out industrialization to promote