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:
May. 25, 1999
Filed:
Jan. 20, 1998
Brian F Becnel, Port Allen, LA (US);
Mahmood Sabahi, Baton Rouge, LA (US);
Kevin J Theriot, Baton Rouge, LA (US);
Albemarle Corporation, Richmond, VA (US);
Abstract
In producing nabumetone or precursor thereof, use is made of 2-bromo-6-methoxynaphthalene formed by (a) methylating 6-bromo-2-naphthol with methyl bromide or methyl chloride, in a halogen-free liquid solvent comprising at least about 40% by weight of one or more compounds of the formula RZ where R is a hydrogen atom or an alkyl group, and Z is a hydroxyl group or a cyanide group with the proviso that if Z is a cyanide group, R is an alkyl group, and in the presence of at least one strong base; and (b) recovering and purifying 2-bromo-6-methoxynaphthalene so formed. The 6-bromo-2-naphthol in turn is preferably formed by reacting 1,6-dibromo-2-naphthol with hydrogen in a halogen-containing liquid solvent comprising at least about 50% by weight of (A) at least one liquid organic halide solvent in which the halogen content has an atomic number of 35 or less or (B) a mixture of water and at least one such liquid organic halide solvent, and in the presence of catalytic amounts of (i) a tungsten carbide-based catalyst, and (ii) at least one phase transfer catalyst, most preferably while purging HBr from the reaction mixture as it is formed. In this way, the quantities of by-products formed in the overall operation are reduced, the need for use of excess iron and/or dimethyl sulfate as reaction components is avoided, and the overall efficiency of plant operation is improved especially when conducted on a large scale.