Patent ID: 9340675
Filing Date: 2016-05-17
CPC Classification: C09B,D06P

Claim Text:
1. A process for manufacturing a dyestuff comprising: (i) providing vegetal biomass; (ii) pretreating said vegetal biomass with an aqueous acidic medium; (iii) neutralizing pretreated vegetal biomass and/or isolating pretreated vegetal biomass in form of a presscake; (iv) mixing pretreated vegetal biomass in (iii) with at least one sulfurization agent selected from the group consisting of sulfur, sulfide, and polysulfide to form a mixture; (v) heating said mixture to a temperature of from 120° C. to 350° C. for at least 2 hours; and (vi) dissolving the mixture in aqueous medium and optionally removing undissolved solid particles.