Abstract: Copper is removed from spent solutions of complexing agents containing cuprous aluminum tetrahalide, such as CuAlCl.sub.4.toluene by (1) contacting said solutions with water so as to form a precipitate of cuprous halide, an aqueous phase and an organic phase; (2) oxidizing the cuprous halide to cupric halide thereby rendering it water soluble; (3) separating the organic phase and aqueous phase, (4) contacting the aqueous phase with an environmentally suitable metal higher than copper from the electromotive series, such as aluminum, thereby precipitating copper metal and (5) separating the precipitated copper metal from the aqueous salt-containing mixture.Alternatively, the spent complex solutions can be contacted with 1 molar to 6 molar aqueous solution of a non-oxidizing acid such as HCl thereby eliminating the necessity of the oxidizing step (2) since the cuprous halide is soluble in the acidified aqueous phase.

Abstract: Cuprous aluminum tetrahalide complexing agents are prepared from cuprous halide such as cuprous chloride contaminated with cupric halide by a method which reduces the cupric ion to the cuprous ion by treating the contaminated cuprous halide with an organo metal compound, such as metal alkyls, metal alkyl halide or metal alkoxides such as diethyl aluminum chloride prior to preparation of the complexing agent by reacting the cuprous halide with an aluminum trihalide such as aluminum trichloride. The pretreatment to remove the cupric ions reduces the amount of aromatic tars formed in processes employing the complexing agents.

Abstract: Heat exchangers which become fouled during cooling of CuAlCl.sub.4 .multidot.solvent (such as toluene) solutions employed in extracting carbon monoxide from acetylene is cleaned by circulating through the fouled exchanger a solvent solution of CuAlCl.sub.4 .multidot.solvent containing aluminum trichloride.