(655g) Catalytic Upgrading of Sugar-Derived Polyols to Glycols in Absence of Externally Added Hydrogen
AIChE Annual Meeting
2018 AIChE Annual Meeting
Catalysis and Reaction Engineering Division
Catalytic Processing of Fossil and Biorenewable Feedstocks I: Acids, Alcohols, and Polyols
Thursday, November 1, 2018 - 2:18pm to 2:36pm
Up to date, it is known most existing hydrogenolysis processes are carried out under high temperature (T > 220 oC) and high H2 pressure conditions (P > 4 MPa), which cause several technological issues such as poor product selectivity due to significant side reactions, fast catalyst deactivation as well as high capital cost and energy consumption.
In this work, we proposed a novel one pot H2 generation and hydrogenolysis process in absence of external H2 under mild conditions (T: 160 oC-200 oC, P: 1.0 Mpa nitrogen atmosphere).We have designed a series of bimetallic Pd-M (M: Cu, Ni, Pt, etc) catalysts supported on active carbon and layered double hydroxides and confirmed their remarkable performances in catalytic conversion of xylitol, sorbitol and mannitol to 1,2-PDO, EG and lactic acid (LA). In particular, catalyst activity and selectivity will be studied for different catalysts. Structure-performance correlations for H2 generation and hydrogenolysis will be established based on bulk and surface characterization using XRD, SEM, TEM and chemisorption. The bimetallic Pd-Ni/AC and Pd-Pt/AC catalysts showed superior hydrogenated activities as well as selectivities towards lactic acid and glycols, compared with other bimetallic catalysts under identical conditions. At nearly 60.0% sorbitol conversion, a selectivity of 36.5% to ethylene glycol, propanediol and other glycols was obtained on Pd-Ni/AC at 200 oC, 1.0Mpa nitrogen atmosphere in absence of external H2. Here we also researched reaction mechanism or pathways by studying metal active sites, H2 spillover effect and the role of solid-base via regulating the growth of Pd-M and the ratio of acidity (basicity). It was concluded that H2-spillover from Pd to M and solid-base acidity (basicity) may strongly influence the reaction mechanism to some extent, thereby influence the activity and selectivity of hydrogenolysis of biomass-derived to chemicals. Further details on reaction pathways and kinetic modeling will also be discussed in this presentation.