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Spent coffee grounds as a renewable source for ecopolyols production
Author(s) -
Soares Belinda,
Gama Nuno,
Freire Carmen S.R.,
BarrosTimmons Ana,
Brandão Inês,
Silva Rui,
Neto Carlos Pascoal,
Ferreira Artur
Publication year - 2015
Publication title -
journal of chemical technology and biotechnology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.64
H-Index - 117
eISSN - 1097-4660
pISSN - 0268-2575
DOI - 10.1002/jctb.4457
Subject(s) - polyol , sulfuric acid , biorefinery , liquefaction , hydroxyl value , biomass (ecology) , chemistry , acid value , pulp and paper industry , catalysis , chemical engineering , viscosity , organic chemistry , polyurethane , materials science , raw material , composite material , engineering , biochemistry , geology , oceanography
BACKGROUND Based on the biorefinery concept, the main focus of this work was the increase in value of spent coffee grounds via an acid liquefaction process using polyhydric solvents in the presence of sulfuric acid, at moderate temperature. For that purpose the effect of temperature, sulfuric acid concentration and time on biomass conversion was studied using design of experiments combined with statistical analysis. RESULTS The ANOVA results (95% confidence level) showed that temperature is the factor with most influence on biomass conversion, within the studied range, while reaction times above 40 min don't seem to bring significant advantages. The maximum conversion obtained in this study was 70 wt% which was achieved at 160°C, 4 wt % of catalyst and 80 min. The polyol obtained using these conditions presented a hydroxyl number value of 199 mg KOH /g polyol and a viscosity of 390 cP, at 25°C. CONCLUSION This work showed that it is possible to convert spent coffee grounds into liquid polyols via an acid liquefaction process at moderate temperature and autogeneous pressure. These polyols have similar properties to those of petroleum‐based polyols typically used in the polyurethane foam industry. © 2014 Society of Chemical Industry