Factors affecting the current and the voltage efficiencies of the synthesis of quaternary ammonium hydroxides by electrolysis-electrodialysis

The applied voltage equation and the current density equation are formulate d for the electrolysis of the anolyte, aqueous quaternary ammonium chloride , and the catholyte, aqueous quaternary ammonium hydroxide, separated with a cation exchange membrane. The two equations reveal the factors that affec t the current efficiency and the voltage efficiency. The effects of the fac tors on the efficiencies were investigated experimentally. The results show that Nafion 901 is a suitable cation exchange membrane, and both the curre nt efficiency and voltage efficiency increase with the decreasing size of t he quaternary ammonium cation, and for the preparation of benzyltriethy-lam monium hydroxide, the current efficiency is well correlated as epsilon (c) = 1.05(I/FC(a)u(c))(-0.16)(I/FC(c)u(0))(0.28), with r(2)=0.96. The voltage efficiency is correlated as epsilon (-1)(nu) - 1 = 3.78 + (-Il/epsilon (0)k appa (m)) + 1.56ln(-Il/epsilon (0)kappa (m)), with r(2)=0.88. (C) 2001 Else vier Science B.V. All rights reserved.