(1) Synthesize 2-hydroxytetrahydropyran: weigh 40g
3,4-dihydro-2H-pyran, 360g of deionized water was added into 600mL reaction kettle, sealed the kettle, replaced with N2 for 3 times and then filled the pressure system of 3MPa, warmed up to 60 , and the reaction was finished after 10h of rapid stirring. Analyzed by gas chromatography, the conversion rate of 3,4-dihydro-2H-pyran was 99.1%, the selectivity of 2-hydroxytetrahydropyran was 91.4%, and the rest of the by-products were dimers of 2-hydroxytetrahydropyran.
(2) Preparation by impregnation method of the catalyst precursor with composition of 20% NiO-1% B2O3/79% SiO2-Al2O3 in terms of oxides were weighed 7.786 g , respectively.
Ni(NO3)3-6H2O, 0.178g
H3BO3 were added to appropriate amount of deionized water and dissolved by stirring and then added to 7.9g SiO2-Al2O3 carrier, stirred to mix uniformly, and then placed in an oven at 110C after standing at room temperature for 2 h. The dried samples were roasted in N2 atmosphere at 450C for 2 h to obtain the catalyst precursors of the desired components. The roasted catalyst precursor was reduced in H2 atmosphere (flow rate of 100 mL/min) at 450C for 2h to obtain active catalyst.
(3) 2-hydroxytetrahydropyran reduction amination reaction: weighing step (1) synthesized 2-hydroxytetrahydropyran and 25% ammonia 150g each added to 600mL reaction kettle, and then add 3g of active catalyst of step (2), sealing the kettle, through the H2 replacement for 3 times will be the H2 pressure up to 3MPa, warming to 100 reaction for 2h, the reaction process by replenishing H2 Maintain a constant pressure, cooling water cooling after the end of the reaction, gas chromatography analysis of the reaction solution in 2-hydroxytetrahydropyran conversion rate of 100%, 5-amino-1-pentanol yield of 90.1%.
