PROCESS FOR PRODUCING BIOBASED a,B-UNSATURATED CARBOXYLIC ACIDS FROM POLY(3-HYDROXYALKANOATE)
AssigneeArkema France
InventorsSerge TRETJAK, Yves CABON
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Abstract
The present invention relates to a process for manufacturing biobased α,β-unsaturated carboxylic acids from biomass containing a poly(3-hydroxyalkanoate), or from a solid poly(3-hydroxyalkanoate) previously extracted from said biomass in the presence of polymerization inhibitors, by thermolysis of said polymer, in the absence of a catalyst, predominantly into α,β-unsaturated carboxylic acid in gaseous form, without using an inert gas to facilitate the evaporation of this acid, This invention more precisely describes the step of thermolysis of the biomass or of the P3HA, followed by the purification steps affording the α,β-unsaturated carboxylic acid and recycling of the intermediate products.
Claims20
A process for manufacturing a biobased α,β-unsaturated carboxylic acid, said process comprising the following steps:
- mixing a biomass containing a poly(3-hydroxyalkanoate) (P3HA), or solid P3HA, with at least one polymerization inhibitor to obtain a biomass/inhibitor mixture or a P3HA/inhibitor mixture, respectively;
- subjecting said biomass/inhibitor mixture or P3HA/inhibitor mixture, without the addition of catalyst and without the addition of an inert gas, to a thermolysis step, resulting in said α,β-unsaturated carboxylic acid in the vapor phase and a molten or solid residue;
- condensing thermolysis gases resulting from thermolysis in one or more steps, and then feeding the resulting condensed thermolysis gases to a distillation column;
- fractionating the thermolysis gases into light products, heavy products recycled to the thermolysis reactor, and α,β-unsaturated carboxylic acid with a purity of greater than 98%, which can be crystallized to reach a purity greater than 99.5%;
- and
- treating the solid-phase residue or recycling it to the thermolysis reactor inlet.
Dependencies are inferred from the claim text.