The Lubrizol Corporation

James L Hambrick

Alan C Clark

Douglas J Hallenburg

Excess amounts of a pure form of acrylonitrile are reacted with other reactants in the production of various compounds such as 2-acrylamido-2-methyl propane sulfonic acid. Accordingly, large amounts of acrylonitrile remain unreacted and present with other contaminants. The present invention is directed toward the purification of such unreacted acrylonitrile and the purified acrylonitrile obtained from such a purification process. The purification is carried out by treating the unreacted acrylonitrile with a base and removing salts formed. The treated material is fed to a heat exchanger which heats the material preferably under vacuum to about 120.degree. F. and provides a heated fluid material. This heated fluid material is pumped to a lower area of a distillation tower which is maintained under vacuum and includes a plurality of distillation trays. Purified acrylonitrile has a lower boiling point and is drawn toward the top of the tower by vacuum and removed whereas the remainder of the material which includes contaminants has a higher boiling point and falls to the bottom of the tower. This bottom portion is removed and recycled to the heat exchanger. The purified acrylonitrile removed from the top of the tower by vacuum is capable of, and sufficiently pure for, reuse in the formation of other compounds such as 2-acrylamido-2-methyl propane sulfonic acid. The process provides purified acrylonitrile while avoiding undesirable polymerization. The purified acrylonitrile obtained from the proces and 2-acrylamido-2-methyl propane sulfonic acid produced with the purified acrylonitrile lack undesirable water insoluble polymers and copolymers and have improved and unexpectedly superior storage stability.

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Chesterland, OH, United States of America

James L Hambrick