Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired
Application number
GB23246/25A
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Hoechst AG
Original Assignee
Hoechst AG
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Filing date
Publication date
Application filed by Hoechst AGfiledCriticalHoechst AG
Publication of GB240168ApublicationCriticalpatent/GB240168A/en
Organic Low-Molecular-Weight Compounds And Preparation Thereof
(AREA)
Abstract
Pure N-dihydroanthraquinoneazine, obtainable according to Specification 184,193, is heated with concentrated sulphuric acid with or without boric acid; the product dyes cotton from the vat in shades which are brighter and faster to chlorine than those yielded by the product obtained from non-purified N-dihydroanthraquinoneazine. The process may be modified by combining the purification of the parent dyestuff and the heating with sulphuric acid into a single operation; in the latter case the crude N-dihydroanthraquinoneazine is heated with concentrated sulphuric acid and boric acid, the mass diluted by addition of weaker sulphuric acid and the product filtered; it may be further purified by fractional precipitation from sulphuric acid. Specifications 339/09 and 23875/09 are referred to.
GB23246/25A1924-09-201925-09-17Manufacture of blue dyestuff
ExpiredGB240168A
(en)