Insight into the green path to dimethyl succinate by direct
esterification of sodium succinate using CO2 and CH3OH
Abstract
The fermentation for the production of succinic acid (SA) outperforms
other methods by low energy consumption and environmental benignity,
with the resulted products mainly as disodium succinate (DSA). By the
direct esterification of DSA using CO2 and CH3OH, it is expected to
avoid the use of inorganic acids in downstream industrial esterification
of bio-based DSA. By high-resolution mass spectrometry analysis and
theoretical calculation,this study establishes that the direct
esterification of DSA consists of three steps by first forming
3-carboxypropanoate,then monomethyl succinate (MMS),and finally DMS. The
reaction kinetics of DSA direct esterification is also investigated by
experiment and simulation with MATLAB, and the reaction kinetics
equation along with reaction rate constant are obtained. The activation
energy for the generation of MMS from DSA is 37.15 kJ/mol,and the one
for the generation of DMS from MMS is 85.80 kJ/mol,indicating the latter
one is the rate-determining step for the direct esterification of DSA.