A process is described for making acrylic acid from dextrose, which comprises fermenting dextrose; removing solids from the resulting fermentation broth; removing lactic acid from the clarified broth by extraction into an organic solvent; separating out the lactic acid-loaded organic solvent while recycling at least a portion of the remainder back to the fermentation step; reacting the lactic acid with ammonia to provide a dehydration feed comprising ammonium lactate while preferably recycling the organic solvent; carrying out a vapor phase dehydration of the ammonium lactate to produce a crude acrylic acid product; and purifying the crude acrylic acid by distillation followed by melt crystallization, chromatography or both melt crystallization and chromatography.

A method is for preparing acrylic acid from β-propiolactone and for using β-propiolactone. The process is based on a specific reactivity of β-propiolactone whereby acrylic acid is formed under operating conditions that are mild, especially in terms of temperature.

A method is for preparing acrylic acid from β-propiolactone and for using β-propiolactone. The process is based on a specific reactivity of β-propiolactone whereby acrylic acid is formed under operating conditions that are mild, especially in terms of temperature.

A catalytic composition useful for the conversion of an olefin selected from the group consisting of propylene, isobutylene or mixtures thereof, to acrylonitrile, methacrylonitrile, and mixtures thereof. The catalytic composition comprises a complex of metal oxides comprising rubidium, bismuth, cerium, molybdenum, iron and other promoters, with a desirable composition.

A catalytic composition useful for the conversion of an olefin selected from the group consisting of propylene, isobutylene or mixtures thereof, to acrylonitrile, methacrylonitrile, and mixtures thereof. The catalytic composition comprises a complex of metal oxides comprising rubidium, bismuth, cerium, molybdenum, iron and other promoters, with a desirable composition.

A method for purifying an easily polymerizable substance efficiently to improve the troublesome matters when cleaning, e.g., reducing the number of times the metal mesh is cleaned. The method for purifying an easily polymerizable substance of the present invention comprises a step of introducing a crude liquid containing the easily polymerizable substance into a distillation column, and a first separation step of introducing a bottoms liquid extracted from a collection part of the distillation column into a wet cyclone, to separate a first purified liquid containing the easily polymerizable substance from a liquid containing an insoluble solid.

A method for purifying an easily polymerizable substance efficiently to improve the troublesome matters when cleaning, e.g., reducing the number of times the metal mesh is cleaned. The method for purifying an easily polymerizable substance of the present invention comprises a step of introducing a crude liquid containing the easily polymerizable substance into a distillation column, and a first separation step of introducing a bottoms liquid extracted from a collection part of the distillation column into a wet cyclone, to separate a first purified liquid containing the easily polymerizable substance from a liquid containing an insoluble solid.

Catalysts and catalytic processes for the synthesis of acrylic acid and other α,β-unsaturated carboxylic acids and their salts, which are carried out in a diluent or in the absence of a diluent. In an aspect, ethylene and CO.sub.2 can be contacted with a Group 8-11 transition metal precursor compound or a Group 8-11 transition metal metalalactone compound in the presence of a metal-treated chemically-modified solid oxide (MT-CMSO) or a metal-treated solid oxide (MT-SO), to form a metal acrylate. As the catalytic activity wanes in either the presence or absence of a diluent, pressure cycling—that is, pressurizing the reaction system with CO.sub.2 and an olefin such as ethylene for a time period, releasing the pressure, then re-pressurizing with CO.sub.2 and ethylene—can rejuvenate the catalyst and restore its declining catalytic activity.

Catalysts and catalytic processes for the synthesis of acrylic acid and other α,β-unsaturated carboxylic acids and their salts, which are carried out in a diluent or in the absence of a diluent. In an aspect, ethylene and CO.sub.2 can be contacted with a Group 8-11 transition metal precursor compound or a Group 8-11 transition metal metalalactone compound in the presence of a metal-treated chemically-modified solid oxide (MT-CMSO) or a metal-treated solid oxide (MT-SO), to form a metal acrylate. As the catalytic activity wanes in either the presence or absence of a diluent, pressure cycling—that is, pressurizing the reaction system with CO.sub.2 and an olefin such as ethylene for a time period, releasing the pressure, then re-pressurizing with CO.sub.2 and ethylene—can rejuvenate the catalyst and restore its declining catalytic activity.

The invention relates to a thermal conversion vessel (200) used during amidification step of acetone cyanohydrin (ACH), in the industrial process for production of a methyl methacrylate (MMA) or methacrylic acid (MAA). The thermal conversion vessel (200) is used for converting an hydrolysis mixture of α-hydroxyisobutyramide (HIBAM), α-sulfatoisobutyramide (SIBAM), 2-methacrylamide (MACRYDE) and methacrylique acid (MAA), into a mixture of 2-methacrylamide (MACRYDE). It comprises:—at least one compartment (C1, C2, C3, . . . Ci) comprising an inner wall (206a, 206b, . . . 206i) separating said compartment into two communicating parts (C1a, C1b) by a passage provided between the bottom of said vessel and said inner wall,—said compartment having a space above said inner wall, for separating gas phase from liquid phase during thermal conversion,—said compartment being connected to an outlet valve (204a, 204b, . . . 204i). Such vessel allows obtaining a high yield thermal conversion in very safe conditions.