Preparation of N,N,N-trimethyl-1-adamantylammonium hydroxide with high purity via bipolar membrane electrodialysis

N,N,N-trimethyl-1-adamantylammonium hydroxide (TMAdaOH) is an organic alkali compound with important applications in the catalyst industry. In this study, bipolar membrane electrodialysis (BMED) was employed for the preparation of TMAdaOH from its halide with a BP-C1-A1-C2-BP four-compartment configuration. The effects of operating conditions (feed concentration and current density) on the performance of BMED were investigated. The results indicated that at optimum operational conditions (feed concentration of 0.3 mol/L and current density of 8 mA·cm−2), a conversion rate of 76.8% can be obtained, with an energy consumption of only 3.22 kWh/kg. The purity of product is extremely high and Cl− content in the TMAdaOH solution can reach as low as 68 ppm. Due to the importance of cation-exchange membrane to the process, different types of cation membrane were compared. In addition, repeated experiments were conducted to prove the stability of BMED process.