| 摘要 |
1,259,121. Dithionite compositions. ALBRIGHT & WILSON Ltd. 30 July, 1969 [1 Aug., 1968], No. 36875/68. Heading D1P. A stabilised substantially anhydrous uniform composition which may be used as a bleaching and reducing agent comprises a metallic dithionite and a cationic, non-ionic or amphoteric surfactant. The preferred dithionite, which may be used as the hydrosulphite, is that of sodium. The surfactant may be formed from ethylene oxide and an aliphatic alcohol, e.g. cetyl and/or stearyl alcohol with a molar ratio of 15-25:1 of oxide: alcohol. Examples are given of suitable surfactants, all of which may be used in compositions containing 0.5 to 40% by weight of surfactant by weight of dithionite. Freeflowing agents, e.g. urea may also be added to the composition in concentration of from 60 to 100% by weight based on the weight of surfactant. The composition may be prepared by adding the dithionite to a melt of the surfactant and cooling to form a solid followed by crushing in a disintegrating mill to form a crushed intimate mixture. |
