Patent Specimen - Rhodol Derivative and Process of Making Same
Maker and role
Johann Brack, Patentee
Johann Brack, Assignor
Basle Chemical Works, Assignee
Production date
Oct 25 1898
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Object detail
Media/Materials
Cotton, paper
Measurements
5 x 3 1/2" (12.7 x 8.9cm)
Description
Brack claims as his invention "1. The improvement in the manufacture of dyestuffs of the phthalein series, which consists in condensing an alkyl ether of a dialkylrhodol with formic aldehyde... 2. The improvement in the manufacture of dyestuffs of the phthalein series, which consists in condensing the ethyl ether of dimethylrhodol with formic aldehyde... [and] 3. As a new article of manufacture, the herein-described dyestuff, the same being a brilliant greenish powder, which is soluble in hot water and in alcohol, dissolves in concentrated sulfuric acid with a yellowish-brown color, can be separated from its solution as a resinous paste, and on printing with ferrocyanid of potassium and oxid of zinc, yields a lake of the same yellowish-red color, which color is not changed by steaming." (Patent Number 613,113)
Collection
Object number
2015.14.3668a,b
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