Bioadditive synthesis from H3PW12O40-catalyzed glycerol esterification with HOAc under mild reaction conditions

In this work, the H3PW12O40 heteropolyacid, a versatile Brønsted acid catalyst promoted a selective conversion of glycerol into mono and diacetylglycerol, in reactions with acetic acid under mild conditions. The activity of the H3PW12O40 catalyst was compared to other Brønsted acid catalysts commonly used in esterification reactions (i.e. p-toluene sulfonic acid and sulfuric acid). The highest glycerol conversions were achieved in H3PW12O40-catalyzed esterification reactions. We demonstrated that unlikely than others homogeneous catalysts, H3PW12O40 may be repeatedly used without loss activity; this way it is also an attractive alternative that may avoid the serious drawbacks of the solid catalysts such as leaching and deactivation. Effects of the HOAc:glycerol molar ratio, acid strength and concentration of the catalysts were also assessed. Additionally, activation energy of the H3PW12O40-catalyzed esterification of glycerol was determined.

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► H3PW12O40 catalyst efficiently promoted glycerol esterification with HOAc.
► H3PW12O40 catalyst was as effective as H2SO4.
► Reaction selectivity was governed by the catalyst and reaction temperature.
► Highest conversion and selectivity for diacetylglycerol was obtained with H3PW12O40.