TECHNOLOGY
Continuous Process Yields Alkyl Acrylates New process from Sohio overcomes problems of previously proposed batch processes 150TH
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Industrial and Engineering Chemistry
A continuous process for converting acrylonitrile to lower alkyl acrylates (ethyl acrylate, for example) has been developed at Standard Oil (Ohio), of Cleveland. The process gets around some of the objections to previously proposed batch processes involving the same reaction scheme. The process's developers, Dr. H. F. Hardman and Dr. A. F. Miller, both of Sohio, explain that in the process, acrylonitrile reacts with one mole of water in the presence of strong acid catalysts to form acrylamide. From here the reaction can proceed in sev eral directions. With molar amounts of sulfuric acid, and under controlled conditions, the reaction yields acryl amide sulfate. With excess water, the reaction proceeds to acrylic acid and ammonium bisulfate. With in
termediate amounts of water, a mix ture containing both acrylamide and acrylic acid is the product. Adding alcohol to the hydrolysis product leads to ester formation. By using different alcohols and adjusting reaction conditions, various lower acrylates can be produced. Ethyl acrylate, the predominant acrylate used in acrylic latexes, is probably the most significant, however. Side reactions, Dr. Hardman says, are one of the main problems in de veloping a process based on this re action scheme. Acrylamide, acrylic acid, and alkyl acrylates all may polymerize. Not only does this re duce yield, but the polymer may plate out on equipment, leading to costly downtime and maintenance. Also, colored polymer, which accumulates in the bottoms, makes costly and dif ficult purification necessary for re covering salable by-product am monium sulfate. Two other problems also present major stumbling blocks. One is the
Sequential Reactors Are Used in Continuous Process for Alkyl Acrylates
Hydrolyzed nitrile
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