Bipolar membrane electrodialysis (BMED) has already been described for the preparation of quaternary ammonium hydroxide. However

compared to quaternary ammonium hydroxide

di-quaternary ammonium hydroxide has raised great interest due to its high thermal stability and good oriented performance. In order to synthesize

N

N

-hexamethylenebis(trimethyl ammonium hydroxide) (HM(OH)

2

) by EDBM

experiments designed by response surface methodology were carried out on the basis of single-factor experiments. The factors include current density

feed concentration and flow ratio of each compartment (feed compartment:base compartment:acid compartment:buffer compartment). The relationship between current efficiency and the above-mentioned three factors was quantitatively described by a multivariate regression model. According to the results

the feed concentration was the most significant factor and the optimum conditions were as follows:the current efficiency was up to 76.2% (the hydroxide conversion was over 98.6%)

with a current density of 13.15 mA·cm

-2

a feed concentration of 0.27 mol·L

-1

and a flow ratio of 20 L·h

-1

:26 L·h

-1

:20 L·h

-1

:20 L·h

-1

for feed compartment

base compartment

acid compartment

and intermediate compartment

respectively. This study demonstrates the optimized parameters of manufacturing HM(OH)

2

by direct splitting its halide for industrial application.