| 摘要 |
Reducing concn. of water-sol. carboxylic impurities esp. AcOH or water-soluble acetates, in Cl-contg. salt solns. is effected by contacting the contaminated aq. salt soln. with Cl2 and exposing the soln. to light having 3600 angstroms wave-length, supplied esp. at 0.1-10 watt luminous energy/28.3 l. of reaction mixt. Reaction pref. requires 1-1.5 moles Cl2/mole carboxylic impurity in salt soln. Chlorinated hydrocarbons, which can be collected, are formed as process by-prods. Salt soln. pH is adjusted w.r.t. pKa of carboxylic contaminant, to satisfy equation pKa - 2.5 = pH = pKa + 1. Cl2 concn. of salt soln. is kept esp. at 50 ppm. Reaction temps. >90 degrees C up to soln. b.pt. are advantageous and obviate cooling of ind. effluents. Process is applicable to carboxylic acid precursors, e.g. alkylene glycols. |
