1) Preparation of glutamic acid N-benzoate
In 1000 mL three-necked flask add sodium glutamate 50 g, water 400 mL and appropriate amount of NaOH. stirring to dissolve, adjust pH 7 ~ 8, at 2 below the same time dropwise addition of benzoyl chloride 37.2 mL and 40% NaOH, control the reaction temperature below 5 , pH 8 plus graduate. Reacted at below 5 for 1 h, adjusted pH 1.5 with 30% HCI, cooled, crystallized, filtered, dried, obtained N-benzoylglutamic acid crude 71.8 g, mp 134~140 .
2) Preparation of propylglutamine
Take N-benzoylglutamic acid crude 60 g (10.24 mot), acetic anhydride 30 g (0.22 mo1). Toluene 75 mL, add to 500 mL three-necked bottle, 85 reaction for 30 min, atmospheric pressure evaporation until no liquid drops (toluene recycling set), add ice water 300 mL. dipropylamine 80 mL to be dissolved. At 0 reaction l h, add acetic acid pH 4.5, stirring, crystallization, over the guess. Filter cake without drying directly add the appropriate amount. Distilled water, sodium carbonate and activated carbon at 80 decolorization 30Min, while hot filter, filtrate adjust pH 4.5, cooling, crystallization, filtration, drying to get boutique 39 g, mp l48 ~ 151 , total yield 53.79%.