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Partial catalytic wet oxidation of lignocellulosic biomass for production of carboxylic acids


Publication Details
Authors: Demesa Abayneh, Laari Arto
Publication year: 2017
Language: English
JUFO-Level of this publication: 0
Permanent website address: http://www.wcce10.org/
Open Access: Not an Open Access publication

Abstract

Lignocellulosic biomass, such as
forestry residues or lignin, is a promising alternative to fossil resources for
sustainable production of chemicals and fuels. In this work, production
of carboxylic acids by catalytic partial wet oxidation of lignocellulose and
alkali lignin was studied experimentally at elevated temperature (200 oC)
and pressure (10 bars of O2 partial pressure). Wet oxidation is
especially well-suited process for treatment of low-value, water containing
biomass, which is difficult or expensive to treat by other means. Partial wet
oxidation experiments were conducted in a batch Parr autoclave reactor with an
internal volume of 450 mL, constructed of type 316 stainless steel. The
composition of wet oxidation products in collected liquid samples was analyzed
by high performance liquid chromatography (HPLC). The factors influencing the
total yield of carboxylic acids formed during the partial oxidation of lignocellulose
and lignin were investigated.

Heteropoly acids were used as
homogeneous catalyst to accelerate partial oxidation reactions. Heteropoly
acids are active catalysts for both homogenous and heterogeneous acid-catalyzed
reactions. Heteroploy acids are considered as environmentally benign and
economically feasible catalysts owing to
their inherent advantages, such as the ease of handling and removal,
reusability, fewer side reactions, high proton mobility, stability and
catalytic activity. In this study, three heteropoly acids, H3PW12O40, H3PMo12O40 and H5PV2Mo10O40, were evaluated based on their effectivity
on total carboxylic acids yield and lignin conversion.






Formic,
acetic, and succinic acids were the major products identified in partial oxidation
of alkali lignin. The results showed that longer reaction time favored both the
yield of carboxylic acids and conversion. Among the catalysts used, the
phosphovanadomolybdate catalyst gave the most promising results with carboxylic
acids yield and lignin conversion up to 42% and 100% respectively in 60 min of
reaction time.


Last updated on 2017-09-11 at 08:56