The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Mar. 13, 1990
Filed:
May. 26, 1988
John P Sankey, Warrington, GB;
Robert Johnson, Liverpool, GB;
Interox Chemicals Limited, London, GB;
Abstract
Hitherto processes proposed in recent years for preparing esters of phenol sulphonate salts by reaction between a carboxylic acid chloride and a phenol sulphonate salt place considerable emphasis upon dehydrating the reactants before they are brought into contact in an organic solvent reaction medium. The present invention avoids the problems of employing non-aqueous solvents by carrying out the reaction under aqueous conditions but with controlled alkalinity and water content, especially at a base to phenol sulphonate mole ratio of from 1.3:1 to 1.6:1 and a total water to phenol sulphonate (as the anhydrous material) of not more than 4.5:1. The reaction advantageously employs in preference only a small molar excess of carboxylic acid chloride over the phenol sulphonate and preferably has a reaction temperature controlled to below 30.degree. C., expecially 5.degree. to 20.degree. C. In a further improvement to the process, the difficulty of enhanced contamination with benzoic acid in the products can be ameliorated by employing a small but effective amount of a surfactant, especially an alcohol ethoxylate, in the reaction mixture. The process is especially well suited to making sodium benzoyl oxybenzene sulphonate from sodium phenol sulphonate dihydrate and benzoyl chloride.