Dust-free non-foaming stabilised dithionite prepn. - by mixing with low mol. wt. polypropylene oxide and opt. re-using compacted grained material

摘要

Dust-free dithionites, esp. Na2S2O4, are prepd. by mixing the dithionites with 0.1-3 (esp. 0.2-0.7) wt.% polypropylene oxides having mol. wt. 50-1200. Dithionites are used as bleaching agents in textiles-, pulp- and paper industry and as reducing agents for vat dyes. Dithionites are stabilised against decompsn. by moisture and air-O2 and can be compacted by pressing. Dust-formation and handling is prevented. The prods. dissolve in water and do not foam when dissolved in dye-baths with stirring.