Patent ID: 6403850
Filing Date: 2002-06-11
Classification: C07B,C07C

Abstract:
A method for inhibiting the premature polymerization of ethylenically unsaturated monomers comprising adding to said monomers an effective amount ofA) at least one stable hindered nitroxyl compound having the structural formula: â€ƒwherein R1 and R4 are independently selected from the group consisting of hydrogen, alkyl, and heteroatom-substituted alkyl and R2 and R3 are independently selected from the group consisting of alkyl and heteroatom-substituted alkyl; and X1 and X2 (1) are independently selected from the group consisting of halogen, cyano, COOR7, â€”Sâ€”COR7, â€”OCOR7, wherein R7 is alkyl or aryl, amido, â€”Sâ€”C6H5, carbonyl, alkenyl, or alkyl of 1 to 15 carbon atoms, or (2) taken together, form a ring structure with the nitrogen; B) at least one phenylenediamine, and, optionally, C) at least one nitroaromatic compound.