Nitrosophenols and C-nitrosoanilines as polymerization inhibitors

A process for inhibiting the premature polymerization of an ethylenically unsaturated monomer during production, distillation, purification or storage of the monomer, which comprises:

• incorporating in the monomer, in an effective inhibiting amount sufficient to prevent premature polymerization during production, distillation, purification or storage of said monomer, a blend comprising at least one nitrosophenol compound and at least one C-nitrosoaniline compound selected from the group consisting of:
• 4-nitroso-N-(1,4-dimethylpentyl)aniline, 4-nitroso-N-phenylaniline, 4-nitroso-N-isopropylaniline, 4-nitroso-N,N-dimethylaniline, 4-nitroso-N,N-diethylaniline, 4-nitroso-N,N-diphenylaniline, 4-nitroso-N,N-diisopropylaniline, 4-nitrosoaniline, 2-nitroso-N-(1,4-dimethylpentyl)aniline, 2-nitroso-N-phenylaniline, 2-nitroso-N,N-dimethylaniline, 2-nitroso-N,N-diethylaniline, 2-nitroso-N,N-diphenylaniline, 2-nitrosoaniline, 2-t-butyl-4-nitroso-N-(1,4-dimethylpentyl)aniline, 2-methyl-4-nitroso-N-(1,4-dimethylpentyl)aniline, 2-t-butyl-4-nitroso-N-phenylaniline, 2-methyl-4-nitroso-N-phenylaniline, 4-t-butyl-2-nitroso-N-(1-,4-dimethylpentyl)aniline, 4-t-butyl-2-nitroso-N-phenylaniline, 4t-butyl-2-nitroso-N,N-dimethylaniline, 4-t-butyl-2-nitroso-N,N-diethylaniline, 4t-butyl-1-2-nitroso-N,N-diphenylaniline, 4-nitroso-N-(1,3-dimethyl-butyl)aniline, 2-nitroso-N-(1,3-dimethylbutyl)aniline and 4-t-butyl-2-nitrosoaniline.

A method for distilling a feed comprising at least one polymerizable ethylenically unsaturated monomer, said method comprising the steps of:

• introducing a feed comprising at least one polymerizable ethylenically unsaturated monomer into a distillation apparatus;
• introducing an effective inhibiting amount, sufficient to prevent premature polymerization of said ethylenically unsaturated monomer, of a blend comprising at least one nitrosophenol compound and at least one C-nitrosoaniline compound selected from the group consisting of:
• 4-nitroso-N-(1-,4-dimethylpentyl)aniline, 4-nitroso-N-phenylaniline 4-nitroso-N-isopropylaniline, 4-nitroso-N,N-dimethylaniline, 4-nitroso-N,N-diethylaniline, 4-nitroso-N,N-diphenylaniline, 4-nitroso-N,N-diisopropylaniline, 4-nitrosoaniline, 2-nitroso-N-(1-,4-dimethylpentyl)aniline, 2-nitroso-N-phenylaniline, 2-nitroso-N,N-dimethylaniline, 2-nitroso-N,N-diethylaniline, 2-nitroso-N,N-diphenylaniline, 2-nitrosoaniline, 2-t-butyl-4-nitroso-N-(1-4-dimethylpentyl)aniline, 2-methyl-4-nitroso-N-(1-,4-dimethylpentyl)aniline, 2-t-butyl-4-nitroso-N-phenylaniline, 2-methyl-4-nitroso-N-phenylaniline, 4-t-butyl-2-nitroso-N-(1-4-dimethylpentyl)aniline, 4-t-butyl-2-nitroso-N-phenylaniline, 4-t-butyl=2-nitroso-N,N-dimethylaniline, 4-t-butyl-2-nitroso-N,N-diethylaniline, 4-t-butyl-2-nitroso-N,N-diphenylaniline, 4-nitroso-N-(1,3-dimethyl- butyl)aniline, 2-nitroso-N- (1,3-dimethylbutyl)aniline and 4-t-butyl-2-nitrosoaniline, into said distillation apparatus;
• and distilling said feed under distillation conditions in the presence of said inhibitor blend to recover from said distillation apparatus an overhead product of high purity ethylenically unsaturated monomer and a residual bottoms fraction having a reduced content of polymeric material.

A method for distilling a feed comprising at least one polymerizable ethylenically unsaturated monomer, said method comprising the steps of:

• introducing a feed comprising at least one polymerizable ethylenically unsaturated monomer into a distillation apparatus;
• introducing an effective inhibiting amount, sufficient to prevent premature polymerization of said ethylenically unsaturated monomer, of a blend comprising at least one C-nitrosoaniline compound and at least one nitrosophenol selected from the group consisting of 4-nitroso-N-(1,4-dimethylpentyl)aniline, 4-nitroso-N-phenylaniline, 4-nitroso-N-isopropylaniline, 4-nitroso-N,N-dimethylaniline, 4-nitroso-N,N-diethylaniline, 4-nitroso-N,N-diphenylaniline, 4-nitroso-N,N-diisopropylaniline, 4-nitrosoaniline, 2-nitroso-N-(1,4-dimethylpentyl)aniline, 2-nitroso-N-phenylaniline, 2-nitroso-N,N-dimethylaniline, 2-nitroso-N,N-diethylaniline, 2-nitroso-N,N-diphenylaniline, 2-nitrosoaniline, 2-t-butyl-4-nitroso-N-(1,4-dimethylpentyl)aniline, 2-methyl-4-nitroso-N-(1,4-dimethylpentyl)aniline, 2-t-butyl-4-nitroso-N-phenylaniline, 2-methyl-4-nitroso-N-phenylaniline, 4-t-butyl-2-nitroso-N-(1-,4-dimethylpentyl)aniline, 4-t-butyl-2-nitroso-N-phenylaniline, 4-t-butyl-2-nitroso-N,N-dimethylaniline, 4-t-butyl-2-nitroso-N,N-diethylaniline, 4-t-butyl-2-nitroso-N,N-diphenylaniline, 4-nitroso-N-(l ,3-dimethyl- butyl)aniline, 2-nitroso-N-(1,3-dimethylbutyl)aniline and 4-t-butyl-2-nitrosoaniline, into said distillation apparatus;
• and distilling said feed under distillation conditions in the presence of said inhibitor blend to recover from said distillation apparatus an overhead product of high purity ethylenically unsaturated monomer and a residual bottoms fraction having a reduced content of polymeric material.