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. 25, 1979
Filed:
Jul. 17, 1978
Applicant:
Inventor:
Yunn H Chiang, Andover, MA (US);
Assignee:
Polaroid Corporation, Cambridge, MA (US);
Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
C09B / ;
U.S. Cl.
CPC ...
260392 ;
Abstract
There is described a method for the synthesis of Acid Blue Dye 104 (Color Index. No. 42735) wherein N-benzyl-N-ethyl-toluidinesulfonic acid is reacted with p-diethylaminobenzaldehyde to form leuco Acid Blue Dye 104 which is then isolated and purified with a solvent such as a lower alcohol to provide a very high purity product. The leuco dye is dissolved in a buffer solution of acetic acid and oxalic acid and oxidized by rapidly adding sodium dichromate solution. The Acid Blue Dye is collected and purified to obtain a final product of very high purity and optical transparency.