Ciba-geigy Corporation

Glenn W Brown

Richard B Lund

2-(stilbyl-4')-(naphtho-1',2':4,5)-1,2,3-triazole-2'-sulfonic acid is obtained by diazotizing p-aminostilbene sulfonic acid, coupling the resulting diazonium salt with Tobias acid and then oxidizing the resulting monoazo sodium salt to close the ring and form the naphthotriazolyl moiety, and, more particularly, by performing the ring-closure oxidation step in a solution of the monoazo compound in a mixture of 2-butoxyethanol and water with pressurized air by contacting said solution in the presence of a copper salt catalyst at temperatures in the range 105.degree.-160.degree. C. and at pressures in the range 10-80 psig, for a time sufficient to effect ring-closure.

Manufacturing process for a naphthotriazole stilbene fluorescent agent

A process for preparing bis-diaminostilbene dilsulfonic acid from bis-dinitrostilbene disulfonic acid by an improved Bechamp reduction process is disclosed. The process involves reduction with metallic iron in an acidic medium consisting of 0.033 to 0.27% of acetic acid and 0.38 to 0.76% of sulfuric acid in water at an oxidation-reduction potential (iron/thalamide electrode) in the range 140 to 270 millivolts.

Bechamp reduction of DNS to DAS using H.sub.2 SO.sub.4 and trace of HOAc

An improved synthesis of the bacteriostat 2,4,4'-trichloro-2'-hydroxydiphenylether is disclosed wherein the hydrolysis after diazotization is carried out at 175.degree.-180.degree. C. to increase the yield and reaction rate. The hydrolyzed product is distilled after neutralization to remove the major portion of undesirable colored products and phenolics. The distillate is then extracted with tetrachlorethylene to separate the product from non-phenolic by-products including the 25-28% 2,4,8-trichlorodibenzofuran which are present. The final product of the process then meets F.D.A. and commercial standards for use in soaps and cosmetics.

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Wagarville, AL, United States of America

Glenn W Brown