Betzdearborn, Inc.

Betz Laboratories, Inc.

Inge K Henrici

Graciela B Arhancet

Dwight K Reid

J Frederick Martin

The polymerization of a vinyl aromatic monomer such as styrene is inhibited by the addition of a composition of a benzoquinone derivative and a hydroxylamine compound.

Compositions and methods for inhibiting vinyl aromatic monomer

Compositions and methods for inhibiting vinyl aromatic monomer polymerization during processing are disclosed. The compositions comprise a dinitrosalicylic acid derivative and a hydroxylamine compound. The methods comprise adding the composition to the monomer during processing. The preferred composition comprises 3,5-dinitrosalicylic acid or 3,5-dinitrosalicylic methyl ester and bis-(hydroxypropyl)hydroxylamine.

Compositions and methods for inhibiting the polymerization of vinyl aromatic monomers in oxygen-free processing systems are disclosed. The compositions comprise a hydroxylamine compound, a phenylenediamine compound and a vinyl aromatic monomer. The methods comprise adding to the monomer bis-N,N'(hydroxypropyl)hydroxylamine.

Methods for inhibiting the polymerization of vinyl aromatic monomers in oxygen-free processing systems are disclosed. The methods comprise adding from 1 to 10,000 parts of a combination of a hydroxylamine compound and a phenylenediamine compound to the vinyl aromatic monomer.

Methods for inhibiting vinyl aromatic monomer polymerization

Methods and compositions are provided for inhibiting the polymerization of vinyl aromatic monomers under distillation conditions. The compositions comprise a combination of a phenylenediamine compound and a hydroxylamine compound.

A method for inhibiting fouling during the elevated temperature processing of hydrocarbon comprising adding to the hydrocarbon a composition comprising a catechol having the structure: ##STR1## wherein R is H or C.sub.1 -C.sub.10 alkyl and, an organic acid.

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Spring, TX, United States of America

Inge K Henrici