Method for refining bio-based propylene glycol
AssigneeChangchun Meihe Science and Technology Development Co., Ltd.
InventorYi Yuan
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Abstract
The invention provides a process for refining bio-based propylene glycol, wherein impurities having boiling points close to that of propylene glycol are separated. In this process, C5-C20 oleophilic alcohol compounds, C5-C20 alkanes and/or C4-C20 oleophilic ketone compounds are subjected to azeotropism as an azeotropic solvent together with the bio-based propylene glycol to obtain an azeotrope containing propylene glycol. Then the azeotropic solvent in the azeotrope is separated to obtain a crude propylene glycol which is further purified to obtain propylene glycol.
Claims14
A process for refining bio-based propylene glycol, comprising:
- (i) mixing one-or more azeotropic solvents with bio-based propylene glycol to obtain an azeotrope-containing propylene glycol feed;
- (ii) subjecting the azeotrope-containing propylene glycol feed to reflux in an azeotropic or rectification tower at a pressure of 1 to 101 kPa (absolute);
- (iii) obtaining extracted material from the top of the azeotropic or rectification tower;
- (iv) adding water to the extracted material to dissolve the propylene glycol in the azeotrope;
- (v) separating the water-insoluble azeotropic solvent-from the propylene glycol aqueous solution;
- (vi) obtaining propylene glycol-from dehydration and refining of the resulting propylene glycol aqueous solution;
- wherein the one or more azeotropic solvents comprise nonane and its isomers, undecane and its isomers, and dodecane and its isomers;
- and
- wherein the bio-based propylene glycol comprises propylene carbonate.
Dependencies are inferred from the claim text.