| 摘要 |
<p>A process for bleaching soapstock obtained in the alkali refining of animal and vegetable oils comprises treating the soapstock with a hypochlorite in the presence of a chlorite, both preferably present as sodium salts. The chlorite may be added to the soapstock before, with or after the hypochlorite, but preferably solutions of chlorite and hypochlorite are mixed immediately before addition to the soapstock. The chlorite may be used in quantities from 0.1-10 per cent, preferably 0.5 per cent, and the hypochlorite, as an aqueous solution containing about 14 per cent available chlorine, in quantities between 0.1-20 per cent (equivalent to 0.02-3 per cent alkali metal hypochlorite); the temperature of the soapstock should be 40-100 DEG C., preferably 60 DEG C., and the time of contact between 0.5 and 30 minutes, preferably 15 minutes. If desired, the chlorite and/or hypochlorite may be formed in situ by passing chlorine and/or chlorine dioxide into an alkaline solution of the soapstock.</p> |
