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采用高温下稀硫酸催化葡萄糖的方法制备乙酰丙酸。考察了反应温度、硫酸浓度和搅拌转速对葡萄糖转化率和乙酰丙酸收率的影响,并优化确定了最优反应条件。进一步,分析了最优反应条件下不同葡萄糖初始浓度对乙酰丙酸收率的影响。为了提高高浓度葡萄糖底物反应时乙酰丙酸的收率,采用两种不同的补料方法进行实验:分3次,依次加入7%、6%与5%的葡萄糖;每次均添加3%的葡萄糖,共6次。结果表明:1提高硫酸浓度、反应温度和搅拌速度有利于加快葡萄糖转化和乙酰丙酸生成;2高浓度葡萄糖底物不利于乙酰丙酸的生成,且浓度越高,乙酰丙酸收率越低;3通过补料操作,可使乙酰丙酸收率由44.3%提高至65.9%。
Levulinic acid was prepared by catalyzing glucose with dilute sulfuric acid at high temperature. The effects of reaction temperature, sulfuric acid concentration and stirring speed on the conversion of glucose and the yield of levulinic acid were investigated. The optimal reaction conditions were optimized. Furthermore, the effects of different initial glucose concentrations on levulinic acid yield were analyzed under optimal reaction conditions. In order to improve the yield of levulinic acid at high glucose substrate reaction, two different feeding methods were used to carry out the experiment: in 3 times, 7%, 6% and 5% glucose were added in sequence; 3% Of glucose, a total of 6 times. The results showed that: 1 to improve the concentration of sulfuric acid, reaction temperature and stirring speed is conducive to accelerating glucose conversion and levulinic acid production; 2 high concentration of glucose substrate is not conducive to the formation of levulinic acid, and the higher the concentration levulinic acid yield lower ; 3 By feeding operation levulinic acid yield can be increased from 44.3% to 65.9%.