摘要 |
Salts of the general formula: [(HO-R<1>)xNHyR2_z]<(+)> (O-N-N-O)<(-)> (I)
Ar
wherein R<1> is a C2 to C4 alkylene radical; R<2> is a C1 to C4 alkyl radical; Ar is an optionally substituted aryl radical; x is 1, 2 or3; y is 1, 2 or 3; and z is 0, 1 or 2; and wherein the sum of x+y+z is 4, for example the ethanolamine salt of N-nitrosophenylhydroxylamine ("NPHA"), are effective as polymerization inhibitors for ethylenically unsaturated monomers. The ethanolamine salt can be prepared by reacting ethanolamine with the ammonium salt of NPHA. Advantageously, the ethanolamine salt is soluble in high concentrations in water and a variety of polar organic solvents. |