Donlar Corporation

The Dow Chemical Company

Daniel A Batzel

James F Kneller

Jacob Mazo

Grigory Ya Mazo

R Garth Pews

Larry P Koskan

Abdul R Meah

Robert A Devries

Pulikkottil Jacob Thomas

John E Cadotte

David R Johnson

Kenneth J Stutts

Barney Vallino

Thomas F Stocker

James E Anschutz

Virginia A Hallfrisch

A method for the preparation of a desired molecular weight polysuccinimide by the catalytic polymerization of aspartic acid in the presence of a cyclic carbonate solvent. Polysuccinimide of relatively high weight average molecular weight and high purity can be produced in relatively high yields while employing a relatively low catalyst loading.

Polyaspartate (salt) by polymerizing aspartic acid and hydrolyzing

Production of polysuccinimide in cyclic carbonate solvent

Polysuccinimide is produced by thermal polymerization of a precursor or a reactant admixture that includes an unsaturated compound in a plate-type reactor at temperatures sufficient to initiate polymerization and to form a brittle solid. The so-obtained polysuccinimide can be hydrolyzed to polyaspartic acidor to a polyaspartic acid salt, if desired. The precursor can be a monomer or a mixture of reactants that form polymerizable intermediates.

Process for production of a polysuccinimide and derivatives thereof

To prevent the deterioration of the flux and salt rejection characteristics of polyamide, thin-film, composite reverse osmosis membranes when subjected to relatively high temperature drying conditions, an unsubstituted inorganic ammonium cation salt of an acid is incorporated into the process of manufacture. The ammonium salt can be introduced into the process either before or after the membrane is formed by interfacial polymerization so long as it is added before the membrane is heated.

Use of inorganic ammonium cation salts to maintain the flux and salt

Polysuccinimide of varying molecular weight has been prepared by heat polymerization of aspartic acid in the presence of a sulfur-containing dehydrating agent employing a variety of reaction mixtures and reaction conditions. Sulfur trioxide and heat decomposable sulfur trioxide precursor dehydrating agents are preferred for this purpose. The presence of an acid scavenger within the reaction mixture is desirable and leads to a relatively higher molecular weight polysuccinimide, while the absence of an acid scavenger results in a relatively lower molecular weight polysuccinimide.

Production of a polysuccinimide and derivatives thereof in the presence

Polysuccinimide is prepared by reacting an unsaturated C.sub.2 dicarboxylic acid or anhydride thereof, e.g., maleic acid, fumaric acid, and maleic anhydride, with a particulate ammonium salt that is thermally decomposable to liberate ammonia. The reaction is carried out at a temperature which is above the thermal decomposition temperature of the ammonium salt and for a time period which is sufficient for the acid or anhydride to react with the ammonia liberated from the ammonium salt and for polymerization to occur. The present method avoids the prior art problems of controlling ammonia losses and water removal. The product polysuccinimide can be readily hydrolyzed to polyaspartic acid or a salt thereof, if desired.

Production of polysuccinimide

Aspartic acid precursors such as mono and diammonium maleate, maleamic acid, ammonium maleamate, ammonium malate and mixtures of these and other precursors are copolycondensed thermally with a variety of mono, di and multifunctional monomers containing amino, hydroxyl and carboxyl functional groups. The resulting condensation copolymers and terpolymers contain succinimide units derived from aspartic acid precursors, condensed with other functional group monomers usually though amide and ester linkages. Hydrolysis of the polysuccinimide copolymers and terpolymers with alkali, alkaline earth and ammonium hydroxide produces aspartic acid copolymer and terpolymer salts.

Aspartic acid copolymers and their preparation

A method of making a semipermeable composite membrane comprising a discriminating layer formed insitu by interfacial polymerization is disclosed. The method provides for removal of a water immiscible solvent for a reactant in the interfacial polymerization by physical means not requiring a phase change such as a water knife, air knife, roller, or rubber blade. Composite membranes having good flux, good salt rejection, and low levels of remaining organic solvent are obtained.

Method of making thin film composite membranes

A process for preparing a 3- or 4-hydroxybenzocyclobutene comprises reacting a 3- or 4-halogenzocyclobutene reactant with an alkali metal hydroxide by heating in an aqueous alcohol medium at a temperature from about 50.degree. C. to a temperature at which dimerization or oligomerization of a benzocyclobutene reactant or product is a significant side reaction, in the presence of a metal-containing catalyst, for a time sufficient to convert the halobenzocyclobutene reactant to the hydroxybenzocyclobutene product.

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Skokie, IL, United States of America

Daniel A Batzel