Development of Diethanolamine Selective Production Process Using Shape-Selective Zeolite Catalyst

Ethanolamines are conventionally produced on an industrial scale exclusively by the reaction of ethylene oxide (EO) with an aqueous solution of ammonia. The reaction is a typical consecutive reaction with three steps [NH(3) -> NH(2)(CH(2)OH) -> NH(CH(2)OH)(2) -> N(CH(2)OH)(3)]; therefore, it is difficult to produce diethanolamine with high selectivity. We developed a catalytic process for selective diethanolamine production from EO and anhydrous ammonia using a ZSM-5 zeolite catalyst modified with rare earth elements. This highly active catalyst was able to recognize the difference at molecular level between diethanolamine and triethanolamine. We also succeeded in producing a binderless molded zeolite catalyst having a shape suitable for a fixed-bed reactor. This catalyst does not give problematic impurities due to undesirable reactions over binders. The catalyst deterioration was overcome by developing a regeneration process using high temperature and high-density ammonia gas as a rinse medium.