Catalysis of Organic..

Cao, White, Wang and Frye 28933. Selective Hydrogenolysis of SugarAlcohols over Structured CatalystsChunshe (James) Cao, James F. White, Yong Wang and John G. FryePacific Northwest National Laboratory, 902 Battelle Blvd, MS K8-93, Richland, WA99352chunshecao@yahoo.comAbstractA novel gas-liquid-solid reactor based on monolith catalyst structure was developedfor converting sugar alcohols to value-added chemicals such as propylene glycol.The structured catalyst was used intending to improve product selectivity. Testing atthe pressure of 1,200 psig and 210°C with H 2 to sorbitol molar ratio of 8.9 and aspace velocity range from 0.15 to 5 hr -1 demonstrated that as high as 41 wt% ofpropylene glycol selectivity and 13 wt% ethylene glycol selectivity can be obtained.In addition, monolith catalysts gave higher C3/C2 ratio than that in the conventionaltrickle bed reactor with similar liquid hourly space velocities.IntroductionBio-based feedstocks such as glucose, sorbitol etc. can be converted into value-addedchemicals such as ethylene glycol, 1,2-propylene glycol and glycerol by reactingwith hydrogen over the catalysts (1-4). Such catalytic hydrogenolysis of sugaralcohols occurs in gas-liquid-solid three phase reaction systems. Conventionalreactors used in this process are slurry or trickle bed reactors. In the scale-up andcommercial demonstration, selectivity to desired products may be limited due tosevere mass transfer limitation in the three-phase system. The selectivity to desiredproducts are limited by the resistance in the interfaces of gas-liquid, liquid solid, andgas-solid, preventing the reactant liquid molecules from contacting the catalytic sites.Consequently, the reduced overall reaction rate requires low space velocity operationto achieve high conversion. However, long residence time may cause unwantedsecondary reactions so that the selectivity is compromised.This study uses novel monolith structured catalysts in aiming to improve processproductivity and selectivity. Apart from the advanced characteristics of low pressuredrop, less backmixing, convenient change out of catalysts, the monolith reactorstructure reduces the mass transfer limitation and potentially improves theselectivity.