Some antisolvents for crystallisation of sodium carbonate

The phase behaviour of ten aqueous mixtures of an alkanediol saturated with sodium carbonate was studied: between 40 and 90 degrees C the solubility o f sodium carbonate was measured in mixtures with different alkane-diol to w ater ratios. Six systems featured phase separation: polyethylene-glycol 200 , polyethylene-glycol 400, tri-ethylene-glycol, 1,2-butanediol, 1,3-butaned iol and 1,4-butanediol. Four antisolvents were fully miscible: ethylene gly col, di-ethylene-glycol, glycerol, and 1,2-propanediol. Solubility measurem ents showed that di-ethylene-glycol is the best antisolvent: sodium carbona te recoveries of 99% are achievable. (C) 1999 Elsevier Science B.V. All rig hts reserved.