Methods and compositions for inhibiting styrene polymerization

• US 4,929,778 A
• Filed: 06/05/1989
• Issued: 05/29/1990
• Est. Priority Date: 06/05/1989
• Status: Expired due to Fees

• Current Assignee: BETZ Laboratories Incorporated Somerton RD Trevose PA 19047
• Original Assignee: Betz Laboratories, Inc. (General Electric Company)
• Inventors: Roling, Paul V.
• Primary Examiner(s): Davis, Curtis R.
• Application Number:
  US07/361,170
• Time in Patent Office: 358 Days
• Field of Search: 585/5, 585/2, 585/3, 585/4, 252/403
• US Class Current: 585/3
• CPC Class Codes: C07C 15/46 Styrene; Ring-alkylated styrenes
• CPC Class Codes: C07C 7/20 Use of additives, e.g. for stabilisation

Abstract

Methods and compositions are provided for inhibiting the polymerization of styrene monomer during elevated temperature processing thereof or during storage or shipment of styrene containing product. The compositions comprise a combination of (a) a phenylenediamine compound having at least one N-H bond and (b) a hindered phenol compound. The methods comprise adding from 1-10,000 ppm of the combination to the styrene medium, per one million parts of styrene.

Claims

1. A method of inhibiting polymerization of a vinyl aromatic compound monomer comprising adding to the vinyl aromatic compound monomer an effective inhibiting amount of (a) a phenylenediamine compound having at least one N--H bond therein, and (b) a hindered phenol having the structure ##STR4## wherein R₁ and R₂ may be the same or different, with R₁ and R₂ being independently chosen and selected from the group of C₁ -C₂₀ alkyl, C₁ -C₃₀ alkaryl, and substituted C₁ -C₃₀ alkaryl;

R₃ is selected from the group of C₁ -C₂₀ alkyl, thiophenol, substituted thiophenol, C₁ -C₄₀ alkanoic acid ester, C₁ -C₃₀ alkaryl, substituted C₁ -C₃₀ alkaryl, C₁ -C₆ alkylamino, C₁ -C₆ alkoxy, amine, polynuclear aryl and substituted polynuclear aryl.

2. A method as recited in claim 1 wherein said vinyl aromatic compound comprises styrene.

3. A method as recited in claim 2 wherein said phenylenediamine compound (a) has the structure ##STR5## wherein R₆, R₇, R₈, and R₉ are the same or different and are hydrogen, alkyl, alkaryl, or aralkyl, with the proviso that at least one of R₆, R₇, R₈ or R₉ is hydrogen.

4. A method as recited in claim 3 wherein R₆, R₇, R₈, and R₉ each have from 1-20 carbon atoms except for at least one of R₆, R₇, R₈ or R₉ that is hydrogen.

5. A method as recited in claim 4 wherein (a) comprises N-phenyl-N'"'"'-(1,4-dimethyl-pentyl)-p-phenylenediamine.

6. A method as recited in claim 1 wherein R₁ and R₂ are each independently chosen from C₁ -C₂₀ tert-alkyl and C₁ -C₂₀ alkyl.

7. A method as recited in claim 6 wherein R₃ is chosen from C₁ -C₂₀ alkyl, C₁ -C₄₀ alkanoic acid ester, thiophenol and substituted thiophenol having the structure ##STR6## wherein R₄ and R₅ are each independently selected from C₁ -C₆ alkyl.

8. A method as recited in claim 7 wherein R₁ and R₂ are both tert-butyl and wherein R₃ is methyl.

9. A method as recited in claim 1 wherein the weight ratio of (a):

(b) is from about 2;

1 to about 1;

2.

10. A method as recited in claim 9 wherein the amount of (a) and (b) added, collectively, to said monomer is from about 1-10,000 ppm per one million parts of said monomer.

11. A method as recited in claim 10 wherein the amount of (a) and (b) added, collectively, to said monomer is from about 1-1000 ppm.

12. A method as recited in claim 1 further comprising heating said monomer.

13. A method as recited in claim 1 further comprising distilling said monomer to remove impurities therefrom.

14. Vinyl aromatic monomer anti-polymerization composition comprising a liquid carrier and dissolved or dispersed therein (a) a phenylenediamine compound having at least one N--H bond therein, and (b) a hindered phenol having the structure ##STR7## wherein R₁ and R₂ may be the same or different, with R₁ and R₂ being independently chosen and selected from the group of C₁ -C₂₀ alkyl, C₁ -C₃₀ alkaryl, and substituted C₁ -C₃₀ alkaryl;

R₃ is selected from the group of C₁ -C₂₀ alkyl, thiophenol, substituted thiophenol, C₁ -C₄₀ alkanoic acid ester, C₁ -C₃₀ alkaryl, substituted C₁ -C₃₀ alkaryl, C₁ -C₆ alkoxy, polynuclear aryl and substituted polynuclear aryl.

15. Vinyl aromatic monomer anti-polymerization composition as recited in claim 14 wherein (a) and (b) are present in a weight ratio (a):

(b) of from about 2;

1 to 1;

2.

16. Vinyl aromatic monomer anti-polymerization composition as recited in claim 14 wherein (a) has the structure ##STR8## wherein R₆, R₇, R₈, R₉ are the same or different and are hydrogen, alkyl, aryl, alkaryl or aralkyl with the proviso that at least one of R₆, R₇, R₈ or R₉ is hydrogen.

17. Vinyl aromatic monomer anti-polymerization composition as recited in claim 16 wherein R₆, R₇, R₈, and R₉ each have from 1-20 carbon atoms except for at least one of R₆, R₇, R₈, or R₉ that is hydrogen.

18. Vinyl aromatic monomer anti-polymerization composition as recited in claim 17 wherein (a) comprises N-phenyl-N'"'"'-(1,4-dimethylpentyl)-p-phenylenediamine.

19. Vinyl aromatic monomer anti-polymerization composition as recited in claim 14 wherein R₁ and R₂ are each independently chosen from C₁ -C₂₀ tert-alkyl and C₁ -C₂₀ alkyl.

20. Vinyl aromatic monomer anti-polymerization composition as recited in claim 19 wherein R₃ is chosen from C₁ -C₂₀ alkyl, C₁ -C₄₀ alkanoic acid ester, thiophenol and substituted thiophenol having the structure ##STR9## wherein R₄ and R₅ are each independently selected from C₁ -C₆ alkyl.

21. Vinyl aromatic monomer anti-polymerization composition as recited in claim 20 wherein R₁ and R₂ are both tert-butyl and wherein R₃ is methyl.

22. Vinyl Aromatic monomer anti-polymerization composition as recited in claim 14 wherein said liquid carrier comprises a non-polar organic solvent and wherein (a) and (b) are both dissolved in said solvent.

23. Vinyl aromatic monomer anti-polymerization composition as recited in claim 22 wherein said non-polar organic solvent comprises heavy aromatic naphtha or xylene.

24. Vinyl aromatic monomer anti-polymerization composition as recited in claim 14 further comprising styrene monomer.

25. A method of inhibiting polymerization of a vinyl aromatic compound monomer comprising adding to the vinyl aromatic compound monomer an effective inhibiting amount of (a) phenylenediamine compound having at least one N--H bond therein, and (b) a hindered phenol, said hindered phenol having the structure ##STR10## wherein R₁ is methyl, R₂ is tert-butyl and R₃ is substituted thiophenol having the structure ##STR11## wherein R₄ is methyl and R₅ is tert-butyl.

26. A method of inhibiting polymerization of a vinyl aromatic compound monomer comprising adding to the vinyl aromatic compound monomer an effective inhibiting amount of (a) a phenylenediamine compound having at least one N--H bond therein, and (b) a hindered phenol, said hindered phenol having the structure ##STR12## wherein R₁ and R₂ are both tert-butyl and wherein R₃ is an alkanoic acid ester.

27. A method as recited in claim 26 wherein R₃ comprises octadecyl propionate.

28. Vinyl aromatic monomer anti-polymerization composition comprising a liquid carrier and dissolved or dispersed therein (a) a phenylenediamine compound having at least one N--H bond therein, and (b) a hindered phenol having the structure ##STR13## wherein R₁ is methyl, R₂ is tert-butyl and R₃ is substituted thiophenol having the structure ##STR14## wherein R₄ is methyl and R₅ is tert-butyl.

29. Vinyl aromatic anti-polymerization composition comprising a liquid carrier and dissolved or dispersed therein (a) a phenylenediamine compound having at least one N--H bond therein, and (b) a hindered phenol having the structure ##STR15## wherein R₁ and R₂ are both tert-butyl and wherein R₃ is an alkanoic acid ester.

30. A composition as recited in claim 29 wherein R₃ comprises octadecyl propionate.