Patent ID: 8293673

Claim:
A complex base catalyst comprising a tetraalkyl ammonium hydroxide, a tetraalkyl ammonium salt, and an alkali metal hydroxide or oxide, wherein molar ratio of the tetraalkyl ammonium hydroxide to the alkali metal hydroxide or oxide to the tetraalkyl ammonium salt is selected from the group consisting of 1:0.5:1, 1:1:1, 5:2:2, 0.5:0.5:2, 3:2:2, 2:2:2, and 1:1:2, and the tetraalkyl ammonium salt is represented by a formula of [(R 1 )(R 2 )(R 3 )(R 4 )N] + n X n- wherein R 1 , R 2 , R 3 , and R 4 , identical or different, respectively, is an alkyl having from 1 to 4 carbon atoms and said alkyl being optionally substituted by a hydrophilic substitute, wherein X n- is selected from the group consisting of halide ion, sulfate radical, carbonate radical, phosphate radical, bicarbonate radical, bisulfate radical, C1-C2-alkyl carbonate radical, and C1-C2-alkyl sulfate radical; n is a value of from 1 to 2.