(521f) Investigating the Effect of Micropore Content on Catalytic Activity and Selectivity for Glucose Isomerization to Fructose

The isomerization reaction of glucose to fructose is an economically desirable step in the production of 5-hydroxymethylfurfural (HMF) from fructose. As HMF is a valuable platform chemical for various industrial applications, including the production of bioplastics and biofuels, the use of cheaper glucose offers a potentially cheaper pathway that is of great benefit to the end uses of HMF. To this end, previous work has demonstrated that the functionalization of amine-based catalysts on SBA-15 mesoporous silica supports can produce fructose from glucose. Further, a general case of the glucose isomerization reaction with these materials has demonstrated that the level of microporosity present within the support structure significantly impacts catalytic performance. Many studies synthesize SBA-15 at a temperature of 100°C or less, creating a primarily mesoporous structure connected by a network of micropores. Made in this way, micropores within this support, called REG (regular)-SBA-15, do not contain active sites and present inefficiencies in material design. By contrast, a synthesis temperature of 130°C produces NMP (negligible micropore)-SBA-15, which contains substantially fewer micropores. In a general case of the glucose isomerization reaction, NMP-SBA-15 was shown to ourperform REG-SBA-15 almost threefold.

However, the specific details of the application of NMP-SBA-15 to isomerization of glucose are not fully understood. Preliminary results indicate that tertiary amines placed at high loading on SBA-15 lead to higher rates of conversion, and that selectivity is positively influenced by initial concentration of glucose. As these ideas have not been fully applied to NMP materials, it has become necessary to do so. Here, tertiary amines on both NMP- and REG-SBA-15 will be tested across a range of surface loadings and initial glucose concentrations to determine the optimal reaction conditions for each and to deepen understanding of the effect of micropore content and the differences offered by NMP-SBA-15 supports.