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US 5,254,760 AGranted
Inhibiting polymerization of vinyl aromatic monomers
AssigneeCiba-Geigy Corporation
InventorsRoland A. E. Winter, Sheng-Shing Li, Leslie R. Gatechair, Volker H. von Ahn
Life of this patent
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Abstract
The polymerization of a vinyl aromatic compound, such as styrene, during distillation or purification is very effectively inhibited by the presence of at least one stable nitroxyl compound together with at least one aromatic nitro compound.
Claims23
A composition which comprises
- (a) a vinyl aromatic compound, and
- (b) an effective inhibiting amount, sufficient to prevent premature polymerization during distillation or purification of said vinyl aromatic compound, of a mixture of
- (i) 5 to 95% by weight, based on the total weight of components (i) and (ii), of a stable hindered nitroxyl compound, and
- (ii) 95 to 5% by weight, based on the total weight of components (i) and (ii), of an aromatic nitro compound.
1 more element
A process for inhibiting the premature polymerization of a vinyl aromatic compound during distillation or purification which comprises
- incorporating therein an effective inhibiting amount, sufficient to prevent premature polymerization during distillation or purification of said vinyl aromatic compound, of a mixture of
- (i) 5 to 95% by weight, based on the total weight of components (i) and (ii), of a stable hindered nitroxyl compound, and
- (ii) 95 to 5% by weight, based on the total weight of components (i) and (ii), of an aromatic nitro compound.
Dependencies are inferred from the claim text.