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:
Feb. 23, 1999
Filed:
Dec. 26, 1996
Son T Nguyen, Lake Jackson, TX (US);
Louis L Walker, Clute, TX (US);
Katherine S Clement, Lake Jackson, TX (US);
The Dow Chemical Company, Midland, MI (US);
Abstract
A is a process for removing water from an alkanesulfonic acid such as methanesulfonic acid or ethanesulfonic acid by mixing an azeotropic excess of a phenolic compound with water and the alkanesulfonic acid, then boiling off substantially all of the water, and leaving as a remnant substantially all the alkanesulfonic acid and some of the phenol. This process is particularly useful for recycling an alkanesulfonic acid for a reaction which requires the phenolic compound as one of the reagents. One such reaction is the alkanesulfonic acid catalyzed condensation reaction of a phenolic compound with an .alpha.haloketone to form a chlorinated intermediate of a dihydroxy-.alpha.-alkylstilbene such as 4,4'-dihydroxy-.alpha.-alkylstilbene (DHAMS).