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:
Dec. 02, 1980
Filed:
Jun. 08, 1979
Sakhib M Aliev, Baku, SU;
Vagab S Aliev, Baku, SU;
Novruz I Guseinov, Baku, SU;
Vagif A Nagiev, Baku, SU;
Nuri T Sultanov, Baku, SU;
Other;
Abstract
A method for preparing .alpha.-naphthol according to the present invention comprises sulphonation of naphthalene with an equimolar amount of a concentrated sulphuric acid at a temperature ranging from 30.degree. to 85.degree. C. for a period of from 60 to 120 minutes in the presence of acetic anhydride whereafter .alpha.in an amount of from 0.5 to 1.5 mole per mole of naphthalene. The resulting naphthalene-.alpha.-sulphonic acid is fused with an alkali taken in an amount of 3-4 moles per mole of naphthalene-.alpha.-sulphonic acid at a temperature ranging from 180.degree. to 285.degree. C. for a period of from 10 to 30 minutes. The resulting melt consisting of the alkali metal .alpha.-naphtholate and the alkali metal sulphite is mixed with a polar solvent; the resulting mixture is acidified with a mineral acid taken in an amount equimolar relative to the alkali metal .alpha.-naphtholate, whereafter.alpha.-naphthol is separated from the resulting suspension. The method according to the present invention makes it possible to increase the yield of .alpha.-naphthol up to 98% of the theoretical amount and produce .alpha.-naththol with a purity of up to 99.5%.