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:
Jul. 05, 1977
Filed:
Jul. 16, 1976
Joachim Priemer, Odenthal, DT;
Norbert Schenk, Leverkusen, DT;
Jorg Krekel, Essen, DT;
Wulf Schwerdtel, Leverkusen, DT;
Bayer Aktiengesellschaft, Leverkusen, DT;
Abstract
To isolate naphthoquinone and phthalic anhydride from the gas obtained in the gas phase oxidation of naphthalene, the gas product at 250.degree. to 500.degree. C is first quenched with a counter-current liquid stream of naphthalene, naphthoquinone and phthalic anhydride. The liquid is raised to at most 200.degree. C, cooled and partly recycled, the coolant temperature being within 70.degree. C of the temperature of the liquid being cooled. The portion of the quench liquid which is not recycled is the product, viz. a solution of naphthoquinone and phthalic anhydride in naphthalene. The quenched gas is scrubbed with liquid naphthalene and most of the liquid product is cooled and re-cycled, the balance of the liquid product being passed to the quencher. The gas which leaves the scrubber is substantially free from naphthoquinone and phthalic anhydride. The initial gas may have been pre-cooled by evaporative cooling. The surfaces of the quencher, cooler and pipes of the quenching system are preferably of stainless steel or are smoothed either mechanically or by coating with plastic, enamel, ceramic or metal.