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US 9,067,880 B2Granted
Process for producing methyl methacrylate having reduced biacetyl content
AssigneeRohm and Haas Company
InventorsMichael A. Curtis, David A. Flosser, Jamie J. Juliette, Philippe P. Maillot, Donna Williams
Life of this patent
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Abstract
This invention provides a process for reducing biacetyl in alpha-, beta-unsaturated carboxylic acid esters, particularly in acrylic or methacrylic (hereinafter “(meth)acrylic”) esters, which comprise low levels of weak acid.
Claims9
A process for removing biacetyl from an alpha-, beta-unsaturated carboxylic acid ester, comprising:
- a) treating a crude alpha-, beta-unsaturated carboxylic acid ester to produce said alpha-, beta-unsaturated carboxylic acid ester which comprises biacetyl and has a weak acid content of between 0.001% and 5.0% by weight, based on the total weight of said alpha-, beta-unsaturated carboxylic acid ester;
- wherein the weak acid comprises carboxylic acid selected from the group consisting of acrylic acid and methacrylic acid, and
- b) adding to said alpha-, beta-unsaturated carboxylic acid ester, at a temperature of from 40 to 120° C., from 1 to 10 molar ratio of an aromatic ortho-diamine, based upon moles of biacetyl, to produce an amine-treated ester mixture, said aromatic ortho-diamine having the formula:
- where X is NR3R4 and
- R1, R2, R3, R4, and Y are independently selected from hydrogen, alkyl, phenyl, and naphthyl.
2 more elements
Dependencies are inferred from the claim text.