Zhuang Xiaowei, Feng Yongshun, Qiao Hui, Yang Weiming, Pan Xin
Zhejiang Academy of Forestry, Liuhe Road 399, Hangzhou 310023, China.
Molecules. 2024 Dec 3;29(23):5707. doi: 10.3390/molecules29235707.
Lactic acid is an important platform feedstock for synthesizing various chemicals. Lactic acid is normally converted from any sugar such as glucose, and Sn-β zeolite is an effective catalyst. In this study, β zeolite with different Si/Al ratios was prepared and characterized. Sn precursor is reacted with β zeolite by high-energy mixing and introduced into the framework of β zeolite to obtain Sn-β zeolite with different Si/Al ratios. The physicochemical properties of Sn-β zeolite were characterized by XRD, FTIR, N physical adsorption, UV Vis diffuse reflectance spectroscopy, and pyridine adsorption FTIR. The results showed that when the Si/Al molar ratio of β zeolite was less than 45, the skeleton load of Sn in β zeolite increased effectively with the decrease in aluminum content, and the Lewis acid and Brønsted acid site numbers could be improved. As the Si/Al ratio exceeded 45, the increase in Sn load in β zeolite slowed down, and the Lewis acid and Brønsted acid site numbers were decreased. The results from the catalytic conversion of glucose to lactic acid confirmed that the too high Si/Al ratio caused a decrease conversion rate. The highest performance of the prepared Sn-β zeolites with the highest catalytic efficiency had a glucose conversion rate of 96.69% and lactic acid yield of 39.42% within 7 h at 190 °C in a pressure reactor.
乳酸是用于合成各种化学品的重要平台原料。乳酸通常由任何糖类（如葡萄糖）转化而来，而Sn-β沸石是一种有效的催化剂。在本研究中，制备并表征了具有不同硅铝比的β沸石。通过高能混合使Sn前驱体与β沸石反应，并将其引入β沸石骨架中，以获得具有不同硅铝比的Sn-β沸石。采用XRD、FTIR、N物理吸附、UV Vis漫反射光谱和吡啶吸附FTIR对Sn-β沸石的物理化学性质进行了表征。结果表明，当β沸石的硅铝摩尔比小于45时，β沸石中Sn的骨架负载量随着铝含量的降低而有效增加，Lewis酸和Brønsted酸位点数量得以提高。当硅铝比超过45时，β沸石中Sn负载量的增加减缓，Lewis酸和Brønsted酸位点数量减少。葡萄糖催化转化为乳酸的结果证实，过高的硅铝比导致转化率降低。在压力反应器中于190℃下7小时内，所制备的具有最高催化效率的Sn-β沸石表现出最高性能，葡萄糖转化率为96.69%，乳酸产率为39.42%。
