1. cyanoethanol method: chloroethanol and sodium cyanide react as raw materials to generate cyanoethanol, and cyanoethanol is hydrolyzed in the presence of sulfuric acid to generate acrylic acid.
2. Acrylonitrile hydrolysis method: Due to the rich sources of acrylonitrile, a method for producing acrylate from acrylonitrile was developed. There are two industrialization methods: Societe Ugine method and O-hio method. Acrylonitrile and sulfuric acid are heated to 90℃ to hydrolyze acrylonitrile into acrylamide sulfate, which is further esterified to produce acrylate. In recent years, it has been reported in patents that the yield of ester can reach 95% with acrylonitrile as raw material and one-step production.
3. β -propiolactone method: using acetic acid (or acetone) as raw material and triethyl phosphate as catalyst, ketene is generated by cracking at 625-730℃. Then in the presence of AICI3 or BF3 catalyst, it reacts with anhydrous methyl acetate at 25℃ to produce β -propiolactone. If the target product is acrylic acid, propiolactone is contacted with hot 100% phosphoric acid to form acrylic acid. If the target product is acrylate, crude propiolactone can directly react with the corresponding alcohol and sulfuric acid without purification.
4.Raphael method and improved Raphael method: (1) stoichiometry This method is to react acetylene and nickel carbonyl (providing carbon monoxide) with water or alcohol under mild conditions (40℃, 0. 10 1MPa) to produce acrylic acid or acrylate: (2) acetylene, carbon monoxide and alcohol. After the stoichiometric reaction starts, carbon monoxide and acetylene are introduced, and the reaction can be carried out continuously. 80% of carbon monoxide required for the reaction can be gaseous carbon monoxide, while nickel carbonyl only needs to provide 20%. (4) High-pressure Raphael method The characteristic of this method is that tetrahydrofuran is used as the solvent, and the acetylene needed for the reaction is dissolved in tetrahydrofuran first, which can reduce the risk of high-pressure treatment of acetylene. At the same time, using nickel salt as catalyst, the reaction was carried out at 200-225℃ and 8.110.13 MPa. (5) Direct oxidation of propylene Gas-phase air catalytic oxidation of propylene is the latest method to produce acrylic acid and its esters. Raw material consumption quota: acrylic acid 770kg/t, n-butanol 610 kg/t/t.