Preparing monoalkenyl aromatic monomer-maleic half ester copolymer
AssigneeMonsanto Company
InventorsDavid E. Allberry, Kang I. Lee
Life of this patent
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Abstract
A process which comprises reacting maleic anhydride and a primary or secondary C.sub.1 -C.sub.18 alcohol to form a maleic half ester, and then polymerizing the half ester and monoalkenyl aromatic monomer in ester solvent in the presence of a catalyst to form a solution of monoalkenyl aromatic monomer-maleic half ester copolymer having a weight average molecular weight of at least 110,000 Daltons. After formation of the copolymer, the reaction solution is neutralized to form a mixture of an alkaline salt solution of the copolymer and solvent and then the solvent is removed from the mixture.
Claims17
A process which comprises reacting maleic anhydride and a primary or secondary C.sub.1 -C.sub.18 alcohol to form a maleic half ester, and then polymerizing the half ester and monoalkenyl aromatic monomer in ester solvent in the presence of a catalyst to form a solution of monoalkenyl aromatic monomer-maleic half ester copolymer, the weight ratio of polymerizing reactants to ester solvent being adequate to provide a weight average molecular weight of the copolymer of at least 110,000 Daltons.
A process for preparing an aqueous alkaline salt solution of high molecular weight styrene-maleic anhydride partial ester copolymer which comprises:
- i) reacting maleic anhydride and a primary or secondary C.sub.1 -C.sub.18 alcohol or a mixture of such a primary or secondary alcohol to form one or more maleic half esters;
- ii) polymerizing the one or more half esters and styrene in the presence of a catalyst in ester solvent to form a solution of styrene-maleic half ester copolymer the weight ratio of polymerizing reactants to ester solvent being adequate to provide copolymer weight average molecular weight of at least 110,000 Daltons;
- and then
- iii) neutralizing the reaction solution to form the aqueous alkaline salt solution.
In a solution polymerization process for preparing high molecular weight monoalkenyl aromatic monomer-maleic half ester copolymers, the improvement which comprises using organic ester as the solvent during polymerization at a weight ratio of polymerizing reactants to organic ester adequate to provide a copolymer weight average molecular weight of at least 110,000 Daltons.
Dependencies are inferred from the claim text.