Nitroxide hydroxylamine and phenylenediamine combinations as polymerization inhibitors for ethylenically unsaturated monomer processes
Polymerization inhibitor compositions are provided. The polymerization inhibitor compositions may include at least one hydroxylamine of a nitroxide and at least one phenylenediamine. Methods of inhibiting the unwanted polymerization of monomers are also provided. The methods include adding the presently disclosed polymerization inhibitor compositions to a fluid containing the monomers. The monomers may be ethylenically unsaturated monomers, such as acrylic acid, methacrylic acid, acrylonitrile, methacrylonitrile, acrolein, methacrolein, acrylate, methacrylate, acrylamide, methacrylamide, vinyl acetate, butadiene, ethylene, propylene, and styrene.
1. A method of inhibiting polymerization of methyl methacrylate comprising:
providing a fluid comprising methyl methacrylate;
adding an effective amount of a polymerization inhibitor composition to the fluid, wherein the polymerization inhibitor composition comprises an effective amount of 4-hydroxy-2,2,6,6-tetramethyl piperidinol and an effective amount of N,N′-di-1,4-dimethylpentyl-1,4-phenylenediamine; and
inhibiting polymerization of the methyl methacrylate.
2. The method of claim 1 , wherein the effective amount of the 4-hydroxy-2,2,6,6-tetramethyl piperidinol and the effective amount of the N,N′-di-1,4-dimethylpentyl-1,4-phenylenediamine is from about 1 ppm to about 2,000 ppm by weight of methyl methacrylate.
3. The method of claim 1 , wherein the polymerization inhibitor composition is added continuously or intermittently to the fluid.