MXPA97001250A - Procedure for the recovery of polyhydroxylcanic acid - Google Patents

Abstract

A hydroxyalkanoic acid (PHA) is recovered from material derived from living organisms by dissolving the PHA in a solvent which is a lower ketone, dialkyl ether or a lower alcohol or a monocarboxylic acid ester thereof, separating the solution from said material and recovering the PHA from the solution

Description

PROCEDURE FOR THE RECOVERY OF POLYHYDROXYFLULCHIC ACID DESCRIPTIVE MEMORY This invention relates to a process for the recovery of polyhydroxalkanoic acid. It has been found that it is possible to produce hydroxyacetic acid, for example, polyhydric acid, or inorganic, for example, phycaligenes and in plants. However, the recovery of the polymer, especially from plants in a state of pure sufficiency to be useful as plastic material, presents difficulties. The material derived from plants, for example seeds and fruits, in the present, is known as vegetable matter.]. Surprisingly it has been found that it is possible to carry out an effective separation of aci or polyhydroxyalkanoic acid from material derived from organism containing it by dissolving the polyhydroxyacetic acid (PHA) in a solvent which is a ketone, diachronic ether or an alcohol. or an ester thereof, separating the solution thus formed from the undissolved matter and recovering PHfl from the solution. Therefore, the invention comprises a process in which a polymer of the hydroxyalkanoic acid (PHF1) is recovered from the material derived from living organisms which < it learns to dissolve the PHfl in a solvent that is a lower ketone, diachyl ether, a lower alcohol or a ester itself, separating the solution of said matter and recovering PHfl from the solution. The process is very suitable for the recovery of polymers and copolymers of isobutylic acid, for example, a polymer of hydroxybutyl and hydroxyvalent acids. It is often desirable to crush or grind the vegetable matter before it comes into contact with the solvent to allow intimate contact of the solution with the PHO.If the solvent is soluble with water, it is preferable that the PHft is precipitated from the solution by the addition of water Solvents that are immiscible with water can also be used, in which case the PHfl can be recovered by evaporating the solvent or by cyclizing the temperature whereby the PHH is dissolved at a high temperature and the solution is cooled to a The solvent, in the latter case, may be reused for further extraction of PHfl but it is desirable that this be done to replace at least part of the solvent with fresh solvent to avoid accumulation of impurities during continuous recirculation of the solvent The fresh solvent can be produced by distilling pure solvent from used impure solvent. Preferred preferred water-miscible solvents include lower ketones, especially acetone and lower alcohols, > For example, methanol, ethanol or a propanol r,, e is suitably isopropanol. Said solvents can be used in the presence or absence of water. For example, ethanol / water mixtures may be used which may be azeotropic compositions but are not limited thereto. If the vegetable material contains oil, it is preferable that the oil be extracted from the vegetable material before being treated with this invention. This is done by pressing the vegetable material to expel oil and / or extracting it with a solvent immiscible with water that is suitably a paraffin or containing cycloparaffin, for example, 4 and preferably 5 to 0 carbon s. The immiscible solvent is preferably one that does not dissolve substantial amounts of PHf1. The desired oil and PHfl can be extracted together from vegetable material by dissolving them in a solvent, separating the solids from undissolved plant material and separating the PHfl from the solution, for example by cooling the precipitate or adding a liquid that reduces its solubility in the solvent, for example water. The solvent extraction is preferably carried out at a temperature above 1QD ° C and preferably above 120 ° C. However, it is preferred that the temperature does not exceed substantially 150 ° C to avoid depolymerization of the PHA. Adequately, a ratio of 1.5: 1 to 10: 1 of solvent (rnl) to solid (gram) should be used to ensure ease of handling of the vegetable and solvent mixture and effective recovery of PHfl- The PHfl can be , "Cure by cooling the solution, for example, to 20-80 ° C and preferably 30 to 50 ° C or evaporating the solvent. If a water-soluble solvent is used, the solution may be cooled to a temperature below 100 ° C, for example, at a temperature in the range of 40 to 90 and water may be added, for example 10 to 50 °. C and preferably 25 to 35% by volume of the solution to produce precipitation. In general, the higher the molecular weight of the units of - - onomeros in the PHfl, the lower will be the temperatures necessary to carry out the solution step. Miscibility solvents with low water that can be used include higher alcohols, for example 0 to C 1 alcohols, for example butanol, and amyl alcohol esters containing 4 to 10 carbon atoms, eg, acetate of ethyl acetate and ethyl acetate and higher ketones, for example cyclohexanone, and methyl isobutene. Based on the Hildebrand expression for the square root of the cohesive energy density ("The Solubility of Non Electrolytes", Hildebrand, 3. H .., Scott, RL (1950)), the solubility parameter, we find that the general solvents which have solubility parities between 15 and 30, "Ji / 2 / cm3 / 2 are preferred for a PHA such co or poly 3 ~ hydroxy butyrate or poly 3-h? drox copolymers? -but irato / pol The hydrochloric acid precipitated by the addition of water may be in the form of a gel, which can be compressed to expel water and / or water to leave the pH-PH1. It is preferred that the plant material after treatment in accordance with this invention is used as animal feed, therefore it is preferred that the plant material contains substantial amounts of PHA, for example 10 to 50% by weight of PH. solvents used in this invention are acceptable in animal feed so that waste from the Solvents can be tolerated in the same way. However, it is preferred that substantially all of the solvent be removed from the vegetable waste.

EXAMPLE 1 Spent rape seed meal (the residue remaining after conventional extraction methods for colza seed oil including cooking, grinding, and hexane extraction) is mixed with poly 3-hydrox? But? Polymer particles. at a ratio of 2: 1 by weight of rapeseed meal to polymer. 20 g of the mixture were suspended by stirring in 100 rnl of hexanol solvent and heated to 140 ° C. the solution was kept at 140 ° C for 30 minutes and then the solids in the rapeseed meal were filtered by filtration under pressure at 2 bar using a metal mesh filter cloth.

The polymer solution was cooled to 70 ° C with stirring of the solution, at which point the polymer formed a rigid opaque gel in the solvent. The polymer is recovered from the solvent phase by compressing the polymer gel between closely spaced rotating rolls producing polymer flakes largely lacking in solvent. The expressed solvent could be reused in extractions directly or after appropriate purification methods, i.e., evaporation. The resulting polymer flakes were removed by heating to S0 ° C. The resulting polymer flakes were solvent free and had polymer that was 99.7% pure and a molecular weight of 650,000.

EXAMPLE 2 flrabidopsis tha liana transgemca containing polyhydroxybutyrate 15% acid, as described in Poiper and others Hio / Technology (1995) .13. 142-150, can be treated as follows: 20 g of the dried material are suspended by stirring in 100 ml of isopropanol and heated in a vessel under pressure at 140 ° C for 30 minutes to dissolve the poly 3-h? drox? but? pco. After dissolution of the polymer, the liquid solids are removed by filtration of the solution. The filtered solution of 3-hydroxybutyrate isopropanol or pressure is maintained to avoid evaporation of the solvent). The solvent polymer is recovered by adding at least 30 milliliters of water or by reducing the solution temperature to 30 to 60 ° C and separating the solid polybutyric acid by filtration or centrifugation.

Claims (5)

NOVELTY OF THE INVENTION CLAIMS

1. - A process in which a hydroxy to canoic acid polymer (PHfl) is recovered from material derived from living organisms by dissolving the PHfl in a solvent that is a lower ketone, dialkyl ether or a lower alcohol or a 1-nonocarboxylate acid ester of it, separating the solution from the matter and recovering the. PHfl of the solution.

2. A process according to claim 1, further characterized in that the solvent is a lower ketone, etherialkyl or a lower alcohol.

3. A method according to claim 2, characterized by the fact that the solvent has from 1 to 10 carbon atoms. 4.- A procedure according to 1? claim 1, further characterized in that the solvent is an ester having at most 12 and preferably from 4 to 10 carbon atoms. 5. A method according to any of the preceding claims further characterized in that the material derived from living organisms is derived from microorganisms or plants. 5. A method according to claim 5, further characterized in that the material is vegetable matter < It contains oil by extracting the oil and grinding it and / or grinding it. 7. A process according to claim 6, further characterized in that the extraction of oil is achieved in part by dissolving the oil in a solvent immiscible with water in which the PHA is substantially insoluble. 0. A process according to any of the preceding claims, further characterized in that the PHf1 is a polymer or copolymer of hydroxybutyric acid. 9. A process according to any of the preceding claims further characterized in that the PHA is dissolved at a temperature in the range of 100 to 150 ° C and recovered by cooling the solution to a temperature in the range of 20 to 80 ° C. and preferably from 30 to 50 ° 0, if the solvent is soluble with water, cooling to a temperature of at most 100 ° C or preferring Plómente 20 to 90 ° C and adding gua. 10. A method according to any of the preceding claims further characterized in that the vegetable matter that remains after the extraction of PHfl and the reduction of its solvent content is fed to animals.