Aqueous phase refining method of long-chain dibasic acid in biological fermentation broth

Abstract

The invention discloses an aqueous phase refining method for long-chain dibasic acids in biological fermentation liquid. The fermentation liquid is terminated by ceramic membrane filtration and solid-liquid separation is carried out to obtain the fermentation liquid; Wash to obtain crude long-chain dibasic acid wet filter cake; stir the crude long-chain dibasic acid wet filter cake into a slurry, add disodium EDTA and methyl tert-butyl ether solvent; organic solvent-long-chain dibasic acid mixture is pressed into In the intermediate tank, a large number of long-chain dibasic acids re-precipitated into the water phase; the organic additives were cut out after standing still and recycled to the impurity removal tank, and the lower water phase was pressed into the crystallization discharge tank, filtered, washed, and dried in sequence to obtain long-chain dibasic acids. Chain dibasic acid products. The invention has short process route, low production cost, higher recovery rate, large crystal grain size, high purity, no solid waste products, and is convenient for realizing large-scale industrial production.

Description

technical field [0001] The invention relates to a refining method, in particular to an aqueous phase refining method for long-chain dibasic acids in biological fermentation broth. Background technique [0002] As we all know, the long chain dibasic acid is the choice of C 11 -C 18 Straight-chain alkanes are used as raw materials, which are obtained by oxidizing alkanes through bio-fermentation. Fermentation broth is a complex multiphase system, which contains not only fermentation bacteria, but also various metabolites, emulsions, residual alkanes and culture medium. [1] CN1351006A utilizes one-time acidification and one-time melt decolorization process to effectively reduce the content of impurities such as protein and organic pigments in the product. The appearance of the product is white, the total acid content is greater than 98%, and the single acid content is greater than 98%. Low energy consumption, high melting energy consumption, and easy fouling of equipment are...

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Problems solved by technology

[5] CN102329212A provides a method of using microchannel equipment to realize water phase refining. After demulsification, filtration and decolorization, the fermentation serum is reacted with dilute sulfuric acid through a microchannel reactor, and the crystal slurry enters the crystallization tank for aging, controlled by gradient temperature Crystal growth rate and size, forming crystals with uniform particle size, filtering, washing, and drying to obtain long-chain dibasic acid crystals, equipment selection and cleaning are difficult in this method, long-term fouling is easy to contaminate refined products, impurity indicators do not meet the requirements of polymerization Level product index requirements

[6] CN102976917A provides an aqueous phase refining method for long-chain dibasic acids. After C12-C15 straight-chain alkanes terminate the fermentation broth or heat the terminated fermentation broth to break the emulsification, the unconverted alkanes, yeast, Pigment macromolecules; take the microfiltration membrane supernatant and couple barrier treatment to obtain the fermented supernatant; heat up the fermented supernatant, adjust it to a reasonable pH condition, add a small amount of crystallization aid, add a small amount of sulfuric acid to form a micro-DCA water phase crystal nucleus, and adjust repeatedly When the pH reaches the critical point, the crystallization temperature is raised and lowered, so that DCA crystals grow gradually, and high-quality long-chain dibasic acids are prepared; the above-mentioned method requires high regulation precision, and there are many crystallization gradient control points, so as to realize the industrial scale-up application of polymer grade products and production stability insufficient

[7] CN201310045908.X discloses a method for dissolving and refining long-chain dibasic acid organic solvent acetone or butanone to remove organic amine nitrogen impurities produced by microbial method. The implementation of the process is relatively dangerous, and it is easy to form an explosive gas mixture, and the ketone solvent in the mixture is difficult to recover, which will inevitably pollute the environment, and acetone is unstable in the presence of acid, and it is easy to generate mesityl oxide, which affects the final product. Product Purity and Application

[8] CN1292072C proposes centrifugation or membrane filtration to pretreat the fermented liquid, acidify and crystallize to obtain crude dibasic acid, put the obtained crude product into acetic acid solvent to heat and melt in a certain proportion, heat it at 60-100°C for 30-180 minutes, then cool and crystallize. The product is obtained after solid-liquid separation and drying; although this method solves the design of the current process route for the preparation of long-chain dibasic acid polymerization grade products by fermentation, there are serious equipment corrosion, harsh operating environment, and serious environmental pollution in the actual production process and other production issues

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