METHOD FOR PURIFYING PROPYLENE GLYCOL OBTAINED FROM BIOLOGICAL RAW MATERIALS Russian patent published in 2024 - IPC C07C29/82 B01D3/36 C07C31/20 

FIELD: chemistry.

SUBSTANCE: method for purifying propylene glycol obtained from biological raw materials. This method includes the following steps: (i) mixing one or more azeotropic solvents with bio-derived propylene glycol to produce a charge containing a propylene glycol azeotrope; (ii) boiling the charge containing the propylene glycol azeotrope with reflux in an azeotrope or distillation column at a pressure of 1 to 101 kPa abs.; (iii) obtaining extracted material from the top of the azeotrope or distillation column; (iv) adding water to the extracted material to dissolve the propylene glycol contained in the azeotrope; (v) separating the water-insoluble azeotropic solvent from the aqueous propylene glycol solution; (vi) obtaining propylene glycol by dehydration and purification of the resulting aqueous solution of propylene glycol. The one or more azeotropic solvents are selected from oleophilic C₅-C₂₀ alcohol compounds and oleophilic C₄-C₂₀ ketone compounds, wherein the one or more azeotropic solvents do not include 1-octanol or 1-decanol.

EFFECT: ensuring an increase in the purity of propylene glycol to 99.5% or more under conditions of a propylene glycol extraction rate of 80% or more.

18 cl, 2 dwg, 5 ex