US 4,562,245 AGranted

Extraction process

AssigneeImperial Chemical Industries PLC

InventorJohn F. Stageman

Life of this patent

Estimating the term…

Abstract

A continuous process for the extraction of 3-hydroxybutyrate polymers from micro-organism cells wherein a non-solvent is added to the extracted syrup to permit separation of the polymer and, by distillation, the bulk of the extraction liquid, which may be a solvent/non-solvent mixture, is recovered for re-use. Preferably the non-solvent added to the syrup is also recovered in the distillation.

Claims13

Dependent claims

A continuous, or cyclic batch, process for the extraction of a 3-hydroxybutyrate (HB) polymer from dried, solvent-permeable HB-polymer containing microorganism cells, said process comprising:

(a) contacting said cells with an extraction liquid to form a syrup containing HB-polymer dissolved in the extraction liquid, said extraction liquid consisting of a mixture of
(i) a solvent for said HB-polymer selected from dichloromethane, chloroform, and 1,2-dichloroethane, and
(ii) a non-solvent for said HB polymer selected from methanol and ethanol, with the proviso that the non-solvent is methanol when said solvent is 1,2-dichloroethane,
said extraction liquid containing sufficient of said solvent that said extraction liquid dissolves said polymer under the extraction conditions,
(b) separating said syrup from the undissolved cell residue,
(c) treating said syrup by adding thereto a sufficient quantity of a liquid composition, that is miscible with said syrup so that said syrup is converted to a composition that can be mechanically separated into a solid polymer phase and a liquid phase, and effecting said mechanical separation, said liquid composition
A. consisting of
(iii) said non-solvent, or a mixture of said non-solvent and said solvent, and optionally
(iv) water,
the amount, if any, of water in said liquid composition being such that said separated liquid phase contains less than 20% by weight of water, and
B. having a lower content of said solvent than said extraction liquid,
(d) distilling at least a proportion of said separated liquid phase to recover therefrom the azeotrope formed between said solvent and said non-solvent to leave a residue that is richer in non-solvent than said liquid phase, and
(e) recycling at least a proportion of said recovered azeotrope to the syrup forming stage, the proportion of said liquid phase that is subjected to distillation and of said azeotrope that is recycled being such that at least 80% by weight of said extraction liquid consists of said recycled azeotrope.

10 more elements

Dependencies are inferred from the claim text.

patentgrep

Loading patent…

Abstract

A continuous, or cyclic batch, process for the extraction of a 3-hydroxybutyrate (HB) polymer from dried, solvent-permeable HB-polymer containing microorganism cells, said process comprising:

(a) contacting said cells with an extraction liquid to form a syrup containing HB-polymer dissolved in the extraction liquid, said extraction liquid consisting of a mixture of
(i) a solvent for said HB-polymer selected from dichloromethane, chloroform, and 1,2-dichloroethane, and
(ii) a non-solvent for said HB polymer selected from methanol and ethanol, with the proviso that the non-solvent is methanol when said solvent is 1,2-dichloroethane,
said extraction liquid containing sufficient of said solvent that said extraction liquid dissolves said polymer under the extraction conditions,
(b) separating said syrup from the undissolved cell residue,
(c) treating said syrup by adding thereto a sufficient quantity of a liquid composition, that is miscible with said syrup so that said syrup is converted to a composition that can be mechanically separated into a solid polymer phase and a liquid phase, and effecting said mechanical separation, said liquid composition
A. consisting of
(iii) said non-solvent, or a mixture of said non-solvent and said solvent, and optionally
(iv) water,
the amount, if any, of water in said liquid composition being such that said separated liquid phase contains less than 20% by weight of water, and
B. having a lower content of said solvent than said extraction liquid,
(d) distilling at least a proportion of said separated liquid phase to recover therefrom the azeotrope formed between said solvent and said non-solvent to leave a residue that is richer in non-solvent than said liquid phase, and
(e) recycling at least a proportion of said recovered azeotrope to the syrup forming stage, the proportion of said liquid phase that is subjected to distillation and of said azeotrope that is recycled being such that at least 80% by weight of said extraction liquid consists of said recycled azeotrope.

10 more elements