Claims
- 1. In processes for the preparation of readily polymerizable ethylenically unsaturated aromatic compounds, the improvement which comprises employing a substance selected from lower alkyl esters of 3,5-dinitrosalicyclic acid, phenyl-3,5-dinitrosalicylate, 3,5-dinitro-4-hydroxybenzoic acid, lower alkyl esters of 3,5-dinitro-4-hydroxybenzoic acid, and mixtures thereof as a process inhibitor.
- 2. The process of claim 1 wherein said process inhibitor comprises methyl-3,5-dinitrosalicylate.
- 3. The process of claim 1 wherein said process inhibitor is present in a concentration of about 50 to 3,000 ppm.
- 4. The process of claim 1 wherein said process inhibitor is present in a concentration of about 250 to 2,000 ppm.
- 5. The process of claim 1 wherein said readily polymerizable ethylenically unsaturated aromatic compound is selected from styrene, .alpha.-methylstyrene, vinyl toluene, vinyl naphthalene, divinylbenzene, and mixtures thereof.
- 6. The process of claim 5 wherein said readily polymerizable ethylenically unsaturated aromatic compound comprises styrene.
- 7. In a process for the preparation of styrene which includes a distillation step at elevated temperature and/or reduced pressure, the improvement which comprises providing a substance selected from methyl-3,5-dinitrosalicylate, phenyl-3,5-dinitrosalicylate, 3,5-dinitro-4-hydroxybenzoic acid, and mixtures thereof to the distilland in a concentration of about 250 to 2,000 ppm.
- 8. The process of claim 7 wherein said process inhibitor is present in the distilland in a concentration of about 500 to 1,000 ppm.
DESCRIPTION
This application is a continuation-in-part of U.S. application Ser. No. 390,489, filed June 21, 1982 and now U.S. Pat. No. 4,389,285, entitled "Process Inhibitor for Readily Polymerizable Ethylenically Unsaturated Aromatic Compounds" (Inventors: T. L. Douglas, A. J. Clonce, Jr., and G. C. Jones).
US Referenced Citations (8)
Foreign Referenced Citations (1)
Number |
Date |
Country |
39-1817 |
Feb 1964 |
JPX |
Continuation in Parts (1)
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Number |
Date |
Country |
Parent |
390489 |
Jun 1982 |
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