Abstract
Tetramethylammonium hydroxide (TMAH) (1) solution which was free from chloride ion was synthesized by electrolyzing its formate (6) in an electrolytic cell with a cation exchange membrane, and this salt 6 was synthesized from trimethylamine (2) and methyl formate ( 5 ). Thus, 6 was prepared with a 3000 ml stainless autoclave by dissolving 470 g (8 mol) of 2 and 720 g (12 mol) of 5 in 800 g of methanol and keeping the mixture at 131 °C for 10 h. Its yield was 79.2%. If higher temperature was used in this synthesis, the decomposition of 5 is accelerated, forming a large volume of CO gas, which makes the operation of the reaction dangerous. Next, 268 g (2.25 mol) of 6 was electrolyzed by impressing 20 V for 15 h and 610 g of 30.1% TMAH solution was obtained. Since HCOOH was not perfectly electrolyzed to CO 2gas in the condition of the present study, a small amount of the acid migrated into the catholyte (TMAH solution). Its concentration was about 17 ppm when the concentration of the catholyte was about 16% TMAH. All contaminents of metallic ions were less than 10 ppb, respectively.
