Composition and method for inhibiting polymerization and polymer growth

1. A method for inhibiting polymer growth of a polymer present in ethylenically unsaturated monomers, said monomers selected from the group consisting of styrene, α-methylstyrene, styrene sulfonic acid, divinylbenzene, polyvinylbenzene, alkylated styrene, butadiene and isoprene monomers, said process comprising

(A) providing the polymer to the ethylenically unsaturated monomers; and

(B) adding to the ethylenically unsaturated monomers, an inhibitor composition consisting of:

(i) at least one first inhibitor consisting of a hydrogen donor of the structure

wherein R 104 , R 105 , R 106 , R 107 , R 108 , and R 109 are independently selected from the group consisting of hydrogen, alkyl, aryl, cycloalkyl, heterocyclic, substituted alkyl, substituted aryl, OR 110 , —SR 110 , NO, NO 2 , CN, COR 112 , halogen, and/or any two adjacent groups can be taken together to form ring structure(s), respectively of five to seven members, provided that at least one of R 104 , R 105 , R 106 , R 107 , R 108 , and R 109 is OH;

R 110 and R 111 are independently selected from the group consisting of hydrogen, alkyl, aryl, benzyl, cyclic, heterocyclic, substituted alkyl or aryl where the substituents are C, O, N, S, or P, and COR 102 , or R 110 and R 111 can be taken together to form a ring structure of five to seven members;

R 112 is R 102 , OR 102 , or NR 102 R 103 ,

R 102 and R 103 are independently selected from the group consisting of hydrogen, alkyl, aryl, benzyl, cyclic, heterocyclic, and substituted alkyl or aryl where the substituents are C, O, N, S, or P, or R 102 and R 103 can be taken together to form a ring structure of five to seven members, and

(ii) at least one second inhibitor having the following structural formula:

wherein

R 1 and R 4 are independently selected from the group consisting of hydrogen, alkyl, and heteroatom-substituted alkyl,

R 2 and R 3 are independently selected from the group consisting of alkyl and heteroatom-substituted alkyl, and

X 1 and X 2

(1) are independently selected from the group consisting of halogen, cyano, amido, —S—C 6 H 5 , carbonyl, alkenyl, alkyl of 1 to 15 carbon atoms COOR 7 , —S—COR 7 , —OCOR 7 , wherein R 7 is alkyl or aryl, or

(2) taken together, form a ring structure with the nitrogen; and

(iii) N-phenyl-N′-(1,4-dimethylpentyl)-para-phenylenediamine and wherein the polymer's growth is decreased by the presence of the inhibitor composition.

2. The method of claim 1 , wherein the at least one first inhibitor is 2,4-di-nitro-sec-butyl-phenol.

3. The method of claim 1 , wherein the at least one second inhibitor is 4-oxo-2,2,6,6-tetramethyl-piperidinyloxy.

4. The method of claim 1 , wherein the weight ratio of the at least one first inhibitor and the least one second inhibitor is 10:1.

5. The method of claim 1 , wherein the at least one first inhibitor is present in an amount of 1500 ppm and the at least one second inhibitor is present in an amount of 150 ppm.

6. The method of claim 1 , wherein the polymer's growth is decreased by 2%.

7. The method of claim 1 , wherein the ethylenically unsaturated monomers are selected from the group consisting of styrene, α-methylstyrene, divinylbenzene, polyvinylbenzene and alkylated styrene monomers.

8. The method of claim 1 , wherein the polymer comprises monomers selected from the group consisting of styrene, α-methylstyrene, styrene sulfonic acid, divinylbenzene, polyvinylbenzene, alkylated styrene, butadiene and isoprene monomers.

9. The method of claim 7 , wherein the polymer comprises monomers selected from the group consisting of styrene, α-methylstyrene, divinylbenzene, polyvinylbenzene and alkylated styrene monomers.

10. The method of claim 1 , wherein the monomers which form the polymer are the same as the monomers in which the polymer is present.