Fabrication of weak‐acid functionalized mesoporous carbon solid acid from tannic acid and its use for saccharification of cellulose

Abstract

A series of mesoporous carbon‐based solid acid catalysts were prepared using tannic acid (C76H52O46), a polyphenol compound, as starting carbon materials and SBA‐15 as silica template. The tannic acid catalysts were characterized by use of N2 Adsorption‐Desorption Isotherm, XRD, FTIR, XPS, and titration method. Phenolic hydroxyl group with weak acidity was confirmed as main functional groups in these catalysts based on characterization using FT‐IR and XPS. The catalysts were tested in saccharification of cellulose. Effects of different preparation parameters of catalyst were correlated to its saccharification activity: (a) oxidation using H2SO4 was important factor determined the high catalytic activity of catalysts, proved by comparison of catalytic activity of catalysts after treatment in concentrated H2SO4 and parent materials lacking the functionalization, (b) higher carbon coating also promoted good catalytic activity since it has higher relative percentage of acid functional groups based on XPS measurement, and (c) catalyst that treated by short oxidation time (2 h) could exhibit higher catalytic activity compared with catalysts that treated by longer oxidation time. With a ratio of catalyst/substrate: 0.5/1 (g/g) at 180°C for 1 h, glucose yield and conversion of 31.45 and 53.86% could be obtained. © 2017 American Institute of Chemical Engineers Environ Prog, 37: 850–860, 2018