Background and overview[1]
D-Aminopropanol is a chiral aminoalcohol. Chiral aminoalcohols are optically active and are the core building blocks of many drugs, surfactants and chemicals. For example, aminopropanol is a key intermediate in the synthesis of ofloxacin, and ofloxacin and levoofloxacin are Star is one of the basic drugs in my country; therefore, chiral aminoalcohol compounds have broad application prospects.
Preparation[1]
Preparing the catalyst includes the following steps:
S1: Add 10g of activated carbon, 0.5g of potassium iodide and 0.5ml of hydrochloric acid into a reaction vessel of 20ml of deionized water, stir and mix, and mix evenly to form the first mixed solution; then increase the temperature of the first mixed solution to 80 ℃, perform ultrasonic treatment for 8 hours; freeze-dry the first mixed solution after ultrasonic treatment to obtain a carrier aerogel
S2: Put the carrier aerogel into a tubular heating furnace for calcination. In an argon atmosphere, first increase the temperature of the furnace to 140°C at a heating rate of 2°C/min, and keep it warm for 1 hour; then increase the temperature to 2°C at 2°C/min. The furnace temperature is heated from 140°C to 800°C at a heating rate of /min, and the temperature is maintained for 2 hours to obtain the treated carrier;
S3: First add 0.6g ammonium hexachlororuthenate and 2ml anhydrous ethanol into the reaction vessel filled with deionized water, stir and mix, and form a second mixed liquid after mixing evenly, and then add the second mixed liquid dropwise Add to the treated carrier; after the dropwise addition, put the carrier into the oven for thermal reaction. Under a hydrogen atmosphere, increase the oven temperature to 200°C at a heating rate of 2°C/min. The reaction time is 2h. Preparation of Ru-activated carbon catalyst. Preparation of L-aminopropanol
Put 180g (2.0mol) D-alanine solid, 10g Ru-activated carbon catalyst (activated carbon supported metal Ru) and 1.0L 2.05mol·L-1 of H3PO4 solution into the hydrogenation reactor and stir evenly to completely dissolve the D-alanine solid and evenly disperse the Ru-activated carbon catalyst powder in the solution; seal the reactor , after introducing H2 to exhaust the air, then introducing high-pressure H2 to maintain the pressure at 8.0MPa, while heating to maintain the reaction temperature at 140°C, and reacted for 2 hours. After the reaction is completed, stop heating and cool the material liquid to room temperature, release the H2 pressure at the same time, and then release the reaction slurry from the bottom of the reaction kettle into a centrifuge for solid-liquid separation to obtain Ru-activated carbon. The catalyst solids are used directly in the next batch of hydrogenation reactions. The D-alanine content in the filtrate was measured by high performance liquid chromatography. The results showed that the D-alanine conversion rate was as high as 99.0%, the chirality retention rate was as high as 99.8%, and the Ru-activated carbon catalyst recovery rate in solid-liquid separation reached 100%. The liquid is D-aminopropanol phosphate solution. D-aminopropanol phosphate solution and water are injected into the bipolar membrane electrodialyzer in a co-current flow manner. The membrane stack configuration of the bipolar membrane electrodialyzer is a BP+AM dual-compartment configuration with 12 repetitions. Unit, the BP model is Fumasep FBM (FuMA-Tech GmbH, Germany), the AM model is Neosepta AHA (ASTOM Corporation, Japan), the anode chamber solution and the cathode chamber solution are both 0.30 mol·L-1 H3PO4 solution, the operating temperature is 25℃, and the flow rate is maintained at 240mL min-1. When the conductivity of the alkali chamber solution drops to 900μs cm-1, stop running. H3PO4 solution and pure D-aminopropanol aqueous solution were obtained through bipolar membrane electrodialysis. The analysis results showed that the removal rate of phosphate anion in the D-aminopropanol aqueous solution was Up to 99.9%, the concentration of H3PO4 solution in the acid chamber can reach 2.14mol L-1 (higher than 2.05mol·L-1 ), can be used directly for the next batch of reactions. The D-aminopropanol aqueous solution is obtained by conventional distillation to obtain pure D-aminopropanol product.
References
[1] [Chinese invention] CN201910653274.3 An all-green synthesis method and device for chiral aminoalcohol compounds
