TY - JOUR
T1 - Selective Glucose Isomerization to Fructose via a Nitrogen-doped Solid Base Catalyst Derived from Spent Coffee Grounds
AU - Chen, Season S.
AU - Yu, Iris K.M.
AU - Cho, Dong Wan
AU - Song, Hocheol
AU - Tsang, Daniel C.W.
AU - Tessonnier, Jean Philippe
AU - Ok, Yong Sik
AU - Poon, Chi Sun
N1 - Funding Information:
This work was supported by the Hong Kong Research Grants Council (PolyU 15217818) and Hong Kong Environment and Conservation Fund (K-ZB78, 2016). The first author (S.S. Chen) would like to thank the Fulbright-RGC Hong Kong Research Scholar Award Program.
Publisher Copyright:
© 2018 American Chemical Society.
PY - 2018/12/3
Y1 - 2018/12/3
N2 - In this work, glucose isomerization to fructose was conducted via a solid base biochar catalyst derived from spent coffee grounds and melamine. The X-ray photoelectron spectroscopy spectra identified the majority of pyridinic nitrogen on the biochar surface, which imparted the strong base character of the catalyst. Activity of the catalyst was evidenced by fast conversion of glucose (12%) and high selectivity to fructose (84%) in 20 min at a moderate temperature (120 °C) compared to recently reported immobilized tertiary amines at comparable N concentrations (10-15 mol % relative to glucose). By increasing the reaction temperature to 160 °C, fructose yield achieved 14% in 5 min. The base biochar catalyst showed superior selectivity (>80%) to commonly used homogeneous base catalysts, such as aqueous hydroxides and amines (50-80%) and comparable catalytic activity (-20 mol % conversion within 20 min). Moreover, cosolvent of acetone in the reaction system may increase the overall basicity by stabilizing protonated water clusters via hydrogen bonding, which led to faster conversion and higher fructose selectivity than those in water. Approximately 19% fructose was obtained at 160 °C, and the basic sites on the biochar catalyst were stable in hydrothermal environment, as indicated by an acid-base titration test. Therefore, nitrogen-doped engineered biochar can potentially serve as a green solid base catalyst for biorefinery processes.
AB - In this work, glucose isomerization to fructose was conducted via a solid base biochar catalyst derived from spent coffee grounds and melamine. The X-ray photoelectron spectroscopy spectra identified the majority of pyridinic nitrogen on the biochar surface, which imparted the strong base character of the catalyst. Activity of the catalyst was evidenced by fast conversion of glucose (12%) and high selectivity to fructose (84%) in 20 min at a moderate temperature (120 °C) compared to recently reported immobilized tertiary amines at comparable N concentrations (10-15 mol % relative to glucose). By increasing the reaction temperature to 160 °C, fructose yield achieved 14% in 5 min. The base biochar catalyst showed superior selectivity (>80%) to commonly used homogeneous base catalysts, such as aqueous hydroxides and amines (50-80%) and comparable catalytic activity (-20 mol % conversion within 20 min). Moreover, cosolvent of acetone in the reaction system may increase the overall basicity by stabilizing protonated water clusters via hydrogen bonding, which led to faster conversion and higher fructose selectivity than those in water. Approximately 19% fructose was obtained at 160 °C, and the basic sites on the biochar catalyst were stable in hydrothermal environment, as indicated by an acid-base titration test. Therefore, nitrogen-doped engineered biochar can potentially serve as a green solid base catalyst for biorefinery processes.
KW - Biomass valorization
KW - Biorefinery
KW - Carbon-based catalyst
KW - Engineered biochar
KW - Food waste recycling
KW - Glucose isomerization
UR - http://www.scopus.com/inward/record.url?scp=85056326894&partnerID=8YFLogxK
U2 - 10.1021/acssuschemeng.8b02752
DO - 10.1021/acssuschemeng.8b02752
M3 - Article
AN - SCOPUS:85056326894
VL - 6
SP - 16113
EP - 16120
JO - ACS Sustainable Chemistry and Engineering
JF - ACS Sustainable Chemistry and Engineering
SN - 2168-0485
IS - 12
ER -