Hong Je Cho, a chemical engineering graduate student working in the research lab of ChE Professor Wei Fan, recently published articles in two of the most impactful journals in the general field of catalysis, meaning the increase in the rate of a chemical reaction of one or more reactants due to the participation of an additional substance called a catalyst. “One of my students, Hong Je Cho, just had two papers published on ACS Catalysis and Green Chemistry,” said Fan. “The two journals have highest impact factors in the fields of catalysis, one is 5 and another one is 7. The one published in Green Chemistry is one of the most-read articles so far and selected as front cover [see illustration] of the issue in July.”
The first article, published in Green Chemistry (http://pubs.rsc.org/en/content/articlelanding/2014/gc/c4gc00723a#!divAbstract), deals with “Base free, one-pot synthesis of lactic acid from glycerol using a bifunctional Pt/Sn-MFI catalyst.” The Authors are Cho, Chun-Chih Chang, and Fan.
The abstract was brief and to the point: “Under base free and mild reaction conditions, 80.5% selectivity of lactic acid (LA) was achieved at 89.8% conversion of glycerol using a bifunctional Pt/Sn-MFI catalyst. In the tandem reaction pathway, selective oxidation of glycerol to glyceraldehyde (GLA) and dihydroxyacetone (DHA) was cascaded with Lewis acid catalyzed isomerization of GLA/DHA into LA.”
Fan said, “It is the first time people can convert glycerol into high-value chemical, lactic acid, by an environmentally friendly way. Glycerol is an inevitable by-product from biodiesel production by the trans-esterification of vegetable oils, and lactic acid is used to make PLA polymer, the second most manufactured bioplastic in the world. The high yield (>80%) achieved in the work is very impressive.”
The article in ACS Catalysis (http://pubs.acs.org/doi/abs/10.1021/cs500295u) is entitled “Synthesis of Hierarchical Sn-MFI as Lewis Acid Catalysts for Isomerization of Cellulosic Sugars,” and the authors are Cho, Paul Dornath, and Fan.
As the abstract explained, “Hierarchical stannosilicate molecular sieves with ordered mesoporosity and MFI topology (three dimensionally ordered mesoporous imprinted (3DOm-i) Sn-MFI) were successfully synthesized within the confined space of three dimensionally ordered mesoporous (3DOm) carbon by a seeded growth method. The obtained 3DOm-i Sn-MFI consisting of 30 nm spherical elements forming an opaline structure contains highly ordered mesopores ranging from 4 to 11 nm. Compared with conventional Sn-MFI, 3DOm-i Sn-MFI exhibits superior catalytic performance for the isomerization of cellulosic sugars."
The abstract added that "No diffusion limitation was observed for the isomerization of a triose sugar, dihydroxyacetone (DHA), into methyl lactate (ML). The presence of weak Brønsted acid in the 3DOm-i Sn-MFI catalyst facilitates the reaction by catalyzing the formation of an intermediate, pyruvaldehyde (PA). 3DOm-i Sn-MFI offers significant improvements for the isomerizations of C5 and C6 sugars, such as xylose and glucose, by greatly enhancing molecular transport. The reaction rate of xylose on 3DOm-i Sn-MFI is at least 20 times higher than that on conventional bulky sized Sn-MFI. The reaction rate for glucose is also enhanced by using 3DOm-i Sn-MFI, but to a lesser extent as compared with the reaction of xylose, possibly because glucose cannot diffuse into the 10-membered-ring pore of MFI, and the reaction is catalyzed only on the external surface of the Sn-MFI catalysts."
Cho said, “Zeolite catalyst is one of the most used solid catalysts in petroleum refinery companies. Development of such catalysts for biomass conversion is very exciting. It only uses their original properties, but also requires new features. In this paper, we present one example to reduce the diffusion limitation in zeolite catalysts. In my thesis, we will focus on tailoring the mass transport properties and catalytic activities to develop high efficient catalysts for biomass conversion.” (June 2014)