KR101229377B1 - Process for Preparing ２-Pyrrolidone Using Biomass - Google Patents

Abstract

The present invention comprises the steps of (a) culturing a microorganism containing glutamate decarboxylase as a whole-cell catalyst in a medium containing glutamic acid or glutamate to prepare 4-aminobutyl acid; (b) obtaining the 4-aminobutyl acid from the medium by filtration; And (c) relates to a method for producing 2-pyrrolidone using biomass comprising the step of converting the 4-aminobutyl acid to 2-pyrrolidone. The present invention provides a series of processes for preparing 2-pyrrolidone from glutamic acid or glutamate using biomass. According to the present invention, 2-pyrrolidone is produced in high yield using 4-aminobutyl acid directly using microorganisms as whole cells, and preferably directly using 4-aminobutyl acid which is not subjected to complicated purification processes such as crystallization. It can be manufactured economically. According to the present invention, 2-pyrrolidone can be produced in large quantities with high yield and low production cost. The present invention is suitable for mass production on an industrial scale through the simplification of the process for the production of 2-pyrrolidone.

Description

Process for Preparing 2-Pyrrolidone Using Biomass

The present invention relates to a method for producing 2-pyrrolidone, and to a method for producing 2-pyrrolidone from glutamic acid or glutamate using biomass.

2-pyrrolidone is a useful chemical that is used as an industrial material in a variety of fields, including the manufacture of polymers, solvents in chemical reactions, and special inks.

Representative known methods for preparing 2-pyrrolidone are described in a BASF patent application (WO 03/022811), in which a petrochemical gamma-butyrolactone is continuously reacted with ammonia and high temperature and high pressure in a liquid phase. There is a method of manufacturing. Further, succinic acid or succinic anhydride may be used as starting materials (US Pat. No. 4,904,804) or maleic acid (US Pat. No. 5,912,358) or succinonitrile (US Pat. Nos. 4,325,872, 4,193,925, 4,181,662 and 4,123,438). It is known to manufacture 2-pyrrolidone as a starting material, and these raw materials are oil-dependent, and the price fluctuates severely, and the price is expected to rise continuously due to the lack of petroleum resources.

Because of this expectation, researches to obtain chemicals from inexpensive biomass have been actively conducted. For example, glutamic acid is obtained through fermentation from biomass. Many methods for preparing butyric acid (or 'gaba', 'GABA') are known, and some are also known for preparing 2-pyrrolidone from 4-aminobutyl acid.

Known methods for preparing 2-pyrrolidone from 4-aminobutyl acid include Pathak et al. ( Tetrahedron 46 (5): 1733-1744 (1990)) in 1990. A method of synthesizing 2-pyrrolidone by reacting toluene as a reaction solvent in the presence of aminobutyric acid and excess neutral alumina for about 10 hours at reflux temperature was reported. In 2009, the Korea Research Institute of Chemical Technology In 0128767), 2-pyrrolidone was prepared in the same manner as Pathak described above using toluene as a reaction solvent by adding a catalyst or a dehydrating agent to 4-aminobutyl acid. However, this method has disadvantages in that a filtration process for removing the catalyst after the reaction, generation of additional raw material costs, and separation and purification of 2-pyrrolidone from the reaction solvent are required.

On the other hand, Japanese Patent Application Laid-Open No. 2002-121183 discloses a method for preparing 2-pyrrolidone by reacting 4-aminobutyl acid and water in high temperature, high pressure water (15-30 megapascal) at 200-300 ° C. . However, this method also has the disadvantage of unnecessary utility cost increase and enormous capital investment in mass production due to high temperature and high pressure reaction. Japanese Patent Application Laid-Open No. 2009-159840 discloses various reaction solvent conditions in a method for preparing pyrrolidone using 4-aminobutyl acid, and especially when pyrrolidone is mixed with 4-aminobutyl acid, reaction temperature It is claimed that can be lowered at this time, suggesting 180 ℃ as the preferred reaction temperature. However, this patent also does not provide solutions to problems that may arise during mass production, such as cost problems at reaction temperatures that are too high and difficulty in process operation due to explosive water (water vapor) generated at reaction temperatures of 180 ° C. have.

It is also known that 4-aminobutyl acid decomposes into 2-pyrrolidone and water at the melting point temperature (202 ° C.) (Merck index 430), but using this method for mass production is a large amount at one time. It is not possible to produce 2-pyrrolidone and water by melting 4-aminobutyl acid at the melting point (202 ° C) while stirring. Also, a large amount of water (water vapor) generated at this time is exploded to generate a process solution. There is considerable difficulty in process operation such as overflow.

On the other hand, there is no prior art for the entire process of finally producing pyrrolidone using biomass from glutamic acid or glutamate. If an efficient process for producing pyrrolidone from glutamic acid or glutamate using biomass is developed, it will greatly improve the economics in the field of pyrrolidone production.

Numerous papers and patent documents are referenced and cited throughout this specification. The disclosures of the cited papers and patent documents are incorporated herein by reference in their entirety to better understand the state of the art to which the present invention pertains and the content of the present invention.

The inventors have sought to develop a method that can produce 2-pyrrolidone in high yield and low production costs in large quantities. As a result, the present inventors have completed the present invention by developing a process protocol capable of producing 2-pyrrolidone in large quantities from glutamic acid or glutamate using biomass directly in high yield and low production cost.

It is therefore an object of the present invention to provide a method for preparing 2-pyrrolidone.

Other objects and advantages of the present invention will become more apparent from the following detailed description of the invention, claims and drawings.

According to an aspect of the present invention, the present invention provides a method for preparing 2-pyrrolidone, comprising the following steps:

(a) culturing a microorganism containing glutamate decarboxylase as a whole-cell catalyst in a medium containing glutamic acid or glutamate to produce 4-aminobutyl acid;

(b) obtaining the 4-aminobutyl acid from the medium by filtration; And

(c) converting the 4-aminobutyl acid to 2-pyrrolidone.

The inventors have sought to develop a method that can produce 2-pyrrolidone in high yield and low production costs in large quantities. As a result, the inventors have developed a process protocol capable of producing 2-pyrrolidone in large quantities from glutamic acid or glutamate using biomass directly in high yield and low production cost.

The method of the present invention will be described in detail in each step as follows:

Step (a): Preparation of 4-Aminobutyl Acid Using Biomass

According to the present invention, 4-aminobutyl acid is prepared using microorganisms as whole-cell catalysts without disrupting microorganisms.

Microorganisms as whole-cell catalysts can be used without any physical / chemical modification. Preferably, the microorganism having glutamic acid decarboxylase used as a whole cell catalyst in the present invention is a microorganism pretreated with an organic solvent (preferably hydrophobic organic solvent) in order to destroy the selective permeability of the cell membrane. .

The microorganism used in the present invention is a microorganism having a glutamic acid decarboxylase, preferably the genus Aspergillus, Clostridium, Escherichia, Lactobacillus, Lactococcus or Listeria. And, more preferably, the genus Escherichia, Lactobacillus or Lactococcus, and most preferably the genus Escherichia can be used.

Aspergillus genus microorganisms are preferably Aspergillus Accuritus ( Aspergillus aculeatus), Aspergillus shi Ruth (Aspergillus caesiellus ), Aspergillus Candiceus ( Aspergillus candidus), Aspergillus Kani-house (Aspergillus carneus ), Aspergillus Crebatus ( Aspergillus clavatus), Aspergillus deploy rack tooth (Aspergillus deflectus), Aspergillus Fisher valerian (Aspergillus fischerianus), Aspergillus Flavus ( Aspergillus (Aspergillus oryzae) on flavus), Aspergillus Duck characters, Aspergillus Perigatus ( Aspergillus) fumigatus), Aspergillus Grau kusu (Aspergillus glaucus), Aspergillus Nidulans ( Aspergillus nidulans ), Aspergillus Niger ( Aspergillus niger ) or Aspergillus Okracius ( Aspergillus can be used. ochraceus), more preferably from Aspergillus Fisher valerian (Aspergillus fischerianus), Aspergillus Playa booth (Aspergillus flavus) or Aspergillus It is used in duck chair (Aspergillus oryzae), and may be used most preferably (Aspergillus oryzae) to the Aspergillus duck characters.

The Clostridium spp are preferably Clostridium acetonitrile part Tilly kyum (C. acetobutylicum), Clostridium acetonitrile Le Lance (C. aerotolerans), Clostridium at tea (C. baratii), Clostridium Bay tingling key (C. beijerinckii), Clostridium non peomen Tansu (C. bifermentans), Clostridium puff Lin Jeans (Clostridium perfingens), Clostridium botyul dimethylanilinium (C. botulinum), Clostridium portion Tilly kyum (C. butyricum), Clostridium cadaverine Berry's (C. cadaveris), Clostridium Chow Boy (C. chauvoei), chloride host lithium Claus tree audio form (C. clostridioforme), Clostridium coli car varnish (C. colicanis), Clostridium difficile four days (C. difficile), Clostridium ester dirty Titanium (C. estertheticum), Clostridium Majorca Rocks (C. fallax) or Clostridium page serie (C. feseri) can be used for, and more preferably Clostridium Bay tingling key (C. beijerinckii), Clostridium non peomen Tansu (C. bifermentans ), Clostridium puff Lin Jeans (Clostridium perfingens) or dimethylanilinium botyul Clostridium (C. botulinum) a can be used, and most preferably from Clostridium puff Lin Jeans (Clostridium The perfingens) can be used.

The Escherichia coli microorganisms include Escherichia Alberti (E. albertii), Escherichia fry Blossom state (E. blattae), Escherichia pom Coli (E. coli), Escherichia pom Fernand old Sony (E. fergusonii), Escherichia cheer Manny Hernandez (E. hermannii) or Escherichia E. vulneris may be used, and more preferably, Escherichia Blind state (E. blattae), Escherichia pom Coli (E. coli) or Escherichia fry Pere old can use the Sony (E. fergusonii), most preferably Escherichia fry E. coli can be used. The Escherichia Coli (E. coli) is a general Escherichia coli fry (E. coli), but to be used, glutamic acid decarboxylase is Escherichia fry the genetic modification made to be mass-produced E. coli is preferably used.

The microorganisms of the genus Lactobacillus include Lactobacillus Anse Toto multiple lance (L. acetotolerans), CD in Paris (L. acidifarinae) to Lactobacillus, Lactobacillus Sidipi the sheath (L. acidipiscis), in Lactobacillus CD loose fill (L. acidophilus), Lactobacillus Oh jilriseu (L. agilis), Lactobacillus know Douce (L. algidus), Lactobacillus Ali menta Julius (L. alimentarius), Lactobacillus amyl utility in Syracuse (L. amylolyticus), Lactobacillus Amyl with loose fill (L. amylophilus), Lactobacillus composite stitcher (L. composti), Lactobacillus Crew dwelling rooms (L. crustorum), Lactobacillus index Trinidad kusu (L. dextrinicus), Lactobacillus Video ribonucleic lance (L. diolivorans), when a Lactobacillus ekwi Geneva (L. equigenerosi), Lactobacillus Fur lactofermentum (L. fermentum), Lactobacillus Galina room (L. gallinarum ), Lactobacillus Ganen System (L. ghanensis), Lactobacillus Hill teaches di (L. hilgardii), minus Lactobacillus (L. iners), Lactobacillus Jones you (L. johnsonii), Lactobacillus Rights Mani (L. leichmannii), Lactobacillus N. jelly (L. nagelii ), Lactobacillus Helveticus (L. helveticus), Lactobacillus brevis (L. brevis), Lactobacillus Nourishing Boots (L. buchneri), Lactobacillus Lactis (Lactobacillus lactis ), Lactobacillus Casei (L. casei), Kimchi Lactobacillus (L. kimchii), Lactobacillus Planta Room (L. plantarum), Lactobacillus Leu battery (L. reuteri), Lactobacillus senpeuran between the sheath (L. sanfranciscensis) or Lactobacillus Sake (L. sakei) a can be used, and more preferably, Lactobacillus brevis (L. brevis), Lactobacillus Nourishing Boots (L. buchneri), Lactobacillus lactis (Lactobacillus lactis ) or Lactobacillus L. casei may be used, most preferably Lactobacillus casei Lactobacillus lactis may be used.

The lactococcus microorganism includes lactococcus The garbage (L. garvieae), Lactobacillus nose kusu Lactis (L. lactis), Lactobacillus Nose Fish Couscous Stadium (L. piscium), Lactobacillus nose Syracuse Planta room (L. plantarum ) or Lactococcus lactis lactis (L. raffinolctis) may be used, more preferably Lactococcus Lactis (L. lactis) or Lactococcus You can use the help fish (L. piscium), and may be most preferred to use Lactobacillus lactis nose Syracuse (L. lactis).

The Listeria sp. Microorganism includes Listeria Gray (L. grayi ), Listeria Eno Kuah (L. innocua), a non-Listeria Ivanovic (L. ivanovii), Listeria Jeans monocytogenes (L. monocytogenes), Gary L. siring (L. seeligeri), Listeria Non Thai (L. muttayi) or Listeria It is possible to use L. welshimeri , and more preferably Listeria Ivanovich ratio (L. ivanovii) or Can be used for L. monocytogenes Jeans (L. monocytogenes), it can be used and most preferably L. monocytogenes Jeans (L. monocytogenes).

The selective permeability of microorganisms refers to the transport between inside and outside of cells affected by environmental factors to the water-soluble substrate of the lipid bilayer, which constitutes the cell membrane of the microorganism. It is a semi-permeable membrane that is not made, but since the fat-soluble substance is dissolved in the lipid portion of the cell membrane and permeated, the substance having a high solubility in lipids is easily permeable regardless of the size of the molecule. When the cell membrane reacts with the hydrophobic organic solvent, the semipermeable membrane is destroyed, thereby losing the selective permeability of the cell.

In the present invention, the type and concentration of the hydrophobic organic solvent reacting with the microorganism is important in that the selective permeability of the microorganism is destroyed to increase the content of 2-aminobutyl acid and to allow the recycling of the whole cell catalyst. The organic solvent that reacts with the microorganism and destroys the selective permeability may be preferably a hydrophobic organic solvent, more preferably pentane, hexane, decane, cyclohexane, cyclo Pentane (Cyclopentane), 1-butylene (1-Butylene), 2-butylene (2-Butylene), 1-Pentene (1-Pentene), 2-Pentene (2-Pentene), isobutylene, Carbon tetrachloride, 1-Chlorobutane, 1-Chloropentane, 2-Chloropropane, 1-Chloropropane, 1-Chloropropane, Bromo Bromoethane, Chloroform, Dichloromethane, 1-Nitropropane, Nitromethane, Benzene, Toluene, Xylene, Chloro Chlorobenzene, Aniline, Diethyl ether, Diisopropyl ether, Tetrahydrofuran (Te trahydrofuran, Ethyl acetate, Methyl acetate, Carbon disulfide, Diethyl sulfide, Dimethyl sulfoxide, Diethylamine, Acetonitrile Acetonitrile) and pyridine may be used, and more preferably toluene, chloroform, xylene, and cyclohexane, and most preferably toluene (Pyridine) may be used. Toluene) can be used.

In the present invention, the concentration of the organic solvent is preferably 0.01-20% (v / v), more preferably 0.01-5% (v / v), even more preferably 0.1-1% (v). / v), most preferably 0.2-0.5% (v / v). '(V / v)' represents the volume of the hydrophobic organic solvent / volume of microbial suspension, and when the organic solvent is used at 20% (v / v) or more, problems of inhibition of catalyst activity and recovery of cells are generated. When the organic solvent of 0.01% (v / v) or less is used, the selective permeability of the cell membrane is not easily destroyed.

The microorganisms containing the glutamic acid decarboxylase and the hydrophobic organic solvent are stirred to pretreat the microorganisms. The stirring speed during the stirring is preferably 100-600 rpm, more preferably 200-400 rpm, most preferably 200-300 rpm.

The stirring time during the stirring is preferably 1-60 minutes, more preferably 3-30 minutes, most preferably 5-15 minutes.

In addition, the stirring temperature at the time of the stirring is preferably 4-40 ℃, more preferably 15-35 ℃, most preferably 25-30 ℃.

According to a preferred embodiment of the present invention, after the whole cell catalyst is prepared by the above process, the method may further include suspending in water or a buffer solution. Because the range of pH of glutamic acid decarboxylase activity is 3.5-6.0, if the range is out of the range, the activity is sharply lowered, in the process of glutamic acid is converted to gammaaminobutyl acid by glutamic acid decarboxylase This is because the pH is increased as the protons in the aqueous solution are consumed, and thus it is necessary to adjust it.

More specifically, considering that the pKa value of glutamic acid used in the present invention is about 2.2, glutamic acid in excess of solubility is added to the whole cell catalyst aqueous solution, but the buffer is used so that the initial pH does not drop below 3.5. The pH of the buffer solution used in the present invention is preferably 3.8-8.0, more preferably 4.0-8.0, even more preferably 4.0-7.0, even more preferably 4.0-6.0. The preparation of a buffer solution having a pH of 4.5 uses acetic acid, and the preparation of a buffer solution having a pH of 6.0, 7.0 and 8.0 uses, but is not limited to, phosphoric acid.

On the other hand, when glutamic acid is used as the substrate, the pH of the buffer solution used in the present invention is preferably 4.0-8.0, more preferably 5.0-6.0, more preferably 4.5-6.0, and most preferably 6.0. . When sodium glutamate is used as the substrate in step (b) below, the pH of the buffer solution used in the present invention is preferably 3.8-6.5, more preferably 3.8-6.0, even more preferably 3.8-5.5, Even more preferably 3.8-5.0, most preferably 4.0.

According to the invention, glutamic acid or glutamate (preferably sodium glutamate) is converted to 4-aminobutyl acid by whole cell catalyst.

Glutamic acid used in the present invention is one of 20 protein amino acids, sodium glutamate is the sodium salt of glutamic acid of the structural formula HOOC (CH ₂ ) ₂ CH (NH ₂ ) COONa, molecular weight 169.11.

The biggest feature of the present invention is that in addition to using sodium glutamate to prepare 4-aminobutyl acid, glutamic acid can be used. The price of glutamic acid is lower than that of sodium glutamate, so that the product cost can be lowered when gamma aminobutyric acid is produced using glutamic acid.

The concentration of whole cell catalyst is controlled by the amount of glutamic acid decarboxylase possessed by the catalyst. According to a preferred embodiment of the present invention, in the case of Escherichia coli, in the case of a strain not subjected to artificial genetic manipulation, the concentration is preferably 1 to 30 g / L, more preferably 5 to 20 g / L And most preferably 10-15 g / L. In addition, in the case of E. coli strains genetically engineered to produce large amounts of glutamic acid decarboxylase, the concentration is preferably 1-30 g / L, more preferably 1-10 g / L, and most preferably Preferably 1-5 g / L of strain.

The glutamic acid or sodium glutamate reacting with the whole cell catalyst is biologically prepared from biomass, and may be added to a reaction tank containing the whole cell catalyst in powder form or in an aqueous solution. The amount of glutamic acid or sodium glutamate added is preferably 15-55% by weight, more preferably 30-50% by weight, and most preferably 35-45% by weight, based on the weight of the microbial suspension. If the concentration is less than 15% by weight, the concentration of the resulting gamma aminobutyric acid is low, the industrial value in terms of concentration costs, etc., if the content exceeds 55% by weight is difficult to stir, there is a problem that the conversion rate is reduced to 90% or less . The glutamic acid or sodium glutamate added may be injected in the form of a powder or suspension, and not all glutamic acid necessarily need to be dissolved.

According to a preferred embodiment of the present invention, in the reaction between the whole-cell catalyst and glutamic acid or sodium glutamate, the reaction may further include pyridoxal 5-phosphate (PLP). Pyridoxal-5-phosphate is a coenzyme that acts on various enzyme reactions in vivo, such as racemization of amino acids, amino group transfer reactions, carboxylation reactions, hydrogen release reactions, aldehyde release reactions, and the synthesis of tryptophan from serine and indole. As one, it plays a role in promoting the reaction.

Step (b): Filtration of Media

4-aminobutyl acid is prepared using a medium containing glutamic acid or glutamate as a substrate and a whole cell catalyst, and then the medium is filtered to separate 4-aminobutyl acid from the microbial cells and insoluble components of the medium.

The filtration is for removing microbial cells and insoluble components from the medium. The filtration can be carried out using a variety of methods known in the art, such as centrifugation, filter presses, filtration membranes or filter paper.

According to a preferred embodiment of the present invention, the method further comprises the step of removing activated pigment from the medium by treating activated carbon in the medium between steps (a) and (b).

Activated carbon treatment can be carried out through a variety of methods known in the art, there are largely two methods of treating activated carbon directly to the medium and a method using a column packed with activated carbon. In consideration of the production cost and the convenience of the process, a method of treating activated carbon directly with the medium is more suitable for the present invention.

According to the method of treating activated carbon directly with the medium, the amount of activated carbon treated with the medium is 1-10% by weight, preferably 1.5-4.0% by weight, more preferably 2.0- with respect to the weight of 4-aminobutyl acid in the medium. 4.0 wt%. As can be seen in the following examples, when the throughput of activated carbon exceeds 4.0% by weight, there is a problem that the yield of 2-pyrrolidone is finally reduced by increasing the loss rate of 4-aminobutyl acid in the medium, If the amount of activated carbon is less than 1.5% by weight, the pigment impurities in the medium are not sufficiently removed, resulting in a decrease in yield of 2-pyrrolidone.

Alternatively, activated carbon treatment can be carried out using a column packed with activated carbon. For example, loading a medium on a column packed with activated carbon and obtaining an eluant from the column can yield a 4-aminobutyl acid solution from which the pigment is removed. In the case of using a column, the removal of the pigment and the filtration of the medium can be performed simultaneously.

According to a preferred embodiment of the present invention, the present invention centrifuged the resultant of step (a) to isolate the cells, treated with activated carbon in the separated solution to remove the pigment and then filtered to obtain 4-aminobutyl acid . Preferably, the medium in which the whole cells are separated from the activated carbon is heat treated.

According to a preferred embodiment of the present invention, the solution containing 4-aminobutyl acid obtained through filtration is concentrated and used for 2-pyrrolidone synthesis.

According to a preferred embodiment of the present invention, after step (b), the method further comprises the step of separating the whole cell catalyst and reusing the separated whole cell catalyst. Since the method provided by the present invention uses the microorganisms themselves without undergoing the microbial disruption process, microorganisms having glutamic acid decarboxylase can be easily recovered and used again by centrifugation. Step (a) may be repeated using the recovered microorganisms, and 4-aminobutyl acid may be prepared by further injecting the recovered microorganisms into the reactor in which the 4-aminobutyl acid production reaction has already started.

Step (c): Preparation of 2-pyrrolidone from 4-amino-butyric acid

2-Pyrrolidone is obtained using 4-aminobutyl acid obtained in the above process.

According to a preferred embodiment of the present invention, the 4-aminobutyl acid used in step (c) is not pre-purified. The expression “pre-purified 4-aminobutyl acid” herein refers to crude 4-aminobutyl acid that has not undergone other purification processes (eg, crystallization) in addition to the filtration and / or activated carbon treatment described above.

The conversion of 4-aminobutyl acid to 2-pyrrolidone is basically a lactam cyclization reaction. Synthesis of 2-pyrrolidone using 4-aminobutyl acid can be carried out through various methods known in the art.

According to a preferred embodiment of the present invention, the conversion of 4-aminobutyl acid to 2-pyrrolidone is a method developed by the inventors, which is named "DPSP" (Daesang Pyrrolidone Synthesis Protocol). This DPSP method is an efficient and cost-effective method.

The DPSP method basically includes the following steps:

(c-1) forming a reaction composition in which 4-aminobutyl acid and 2-pyrrolidone are mixed;

(c-2) heat treating the reaction composition to perform a lactam cyclization reaction to produce 2-pyrrolidone and water; And

(c-3) separating the 2-pyrrolidone.

More specifically, the DPSP method includes the DPSP-T method which focuses on temperature control and the DPSP-P method which focuses on pressure control.

According to a preferred embodiment of the invention, the DPSP-T method comprises the following steps:

(a) forming a reaction composition in which 4-aminobutyl acid and 2-pyrrolidone are mixed;

(b) heat treating the reaction composition at a temperature of 118 ° C.-148 ° C. to perform a lactam cyclization reaction to produce 2-pyrrolidone and water; And

(c) separating the 2-pyrrolidone.

According to a preferred embodiment of the invention, the DPSP-P method comprises the following steps:

(a) forming a reaction composition in which 4-aminobutyl acid and 2-pyrrolidone are mixed;

(b) subjecting the reaction composition to heat treatment under reduced pressure to perform a lactam cyclization reaction to produce 2-pyrrolidone and water and to remove the water; And

(c) separating the 2-pyrrolidone.

First, the DPSP-T method is described in detail as follows:

According to the DPSP-T method, a reaction composition is first formed in which 4-aminobutyl acid and 2-pyrrolidone are mixed to provide a suitable environment for the conversion reaction of 4-aminobutyl acid.

When providing a reaction composition in which 2-pyrrolidone coexists in a reactant of 4-aminobutyl acid, a temperature lower than the melting point (202 ° C.) of 4-aminobutyl acid, such as 118, is demonstrated in the examples below. 4-aminobutyl acid is converted to 2-pyrrolidone and water at < RTI ID = 0.0 >

Providing the reaction composition in which 4-aminobutyl acid and 2-pyrrolidone are mixed can be accomplished by various methods.

First, step (a) can be carried out by stirring 4-aminobutyl acid and 2-pyrrolidone in the reactor, i.e. by adding 4-aminobutyl acid and 2-pyrrolidone to the reactor and stirring it A reaction composition is formed in which 4-aminobutyl acid and 2-pyrrolidone are mixed. Such a reaction composition may be subjected to lactam cyclization of 4-aminobutyl acid at a relatively low temperature, such as 118 ° C-148 ° C. Can be.

The amount of 2-pyrrolidone mixed with 4-aminobutyl acid in the first manner is not particularly limited. However, if the amount of 2-pyrrolidone mixed with 4-aminobutyl acid is too small, it is stirred for reaction. However, if too much, the cost of distilling 2-pyrrolidone after the end of the reaction becomes high. Therefore, in consideration of smooth process operation and manufacturing cost, the mixture of 4-aminobutyl acid and 2-pyrrolidone The amount is preferably 1: 0.1-1: 10 by weight, more preferably 1: 0.2-1: 5, even more preferably 1: 0.5-1: 2.

Second, step (a) is added 4-aminobutyl acid to the reactor and the temperature of the reactor is heated to convert 4-aminobutyl acid to 2-pyrrolidone and water, and then 4-aminobutyl acid is further added For example, 4-aminobutyl acid may be added to the reactor, and the temperature of the reactor may be raised to the melting point (202 ° C.) of 4-aminobutyl acid, thereby yielding 2-aminobutyl acid. Conversion to pyrrolidone and water. Then, additional 4-aminobutyl acid is added and dissolved while the reactor is naturally cooled. If necessary, additional addition of 4-aminobutyl acid can be carried out twice.

Third, step (a) may be carried out by introducing 4-aminobutyl acid into the reactor and raising the temperature of the reactor to convert some of the 4-aminobutyl acid into 2-pyrrolidone and water. The difference from this is that all of 4-aminobutyl acid to be converted to 2-pyrrolidone is used from the beginning.

Regardless of which of the three modes is adopted, this procedure provides a reaction composition in which 4-aminobutyl acid and 2-pyrrolidone are mixed.

The reaction composition is then heat treated at a temperature of 118 ° C.-148 ° C. to carry out a lactam cyclization reaction to produce 2-pyrrolidone and water.

Maintaining the reaction composition of step (a) at a suitable temperature causes a lactam cyclization reaction to convert 4-aminobutyl acid to 2-pyrrolidone and water.

According to the prior art (e.g., Japanese Patent Application Laid-Open No. 2002-121183 and Japanese Patent Application Laid-Open No. 2009-159840), 2-aminobutyl acid is added at high temperature (for example, 200-300 ° C or 180 ° C). Convert to pyrrolidone. The present invention proceeds to the lactam cyclization reaction using a mixed reaction composition of 4-aminobutyl acid and 2-pyrrolidone at a temperature significantly lower than the reaction temperature proposed in the prior art, that is 118 ℃-148 ℃ 2 Pyrrolidone and water are produced. If the reaction temperature is less than 118 ° C., the lactam cyclization reaction hardly proceeds, so that little 2-pyrrolidone is produced and the reaction temperature is higher than 148 ° C. (Eg, 200-300 ° C. or 180 ° C.) has difficulty in process operation caused by explosively generated water (steam) and is not suitable for mass production of 2-pyrrolidone. The reaction temperature of 118 ° C.-148 ° C. proposed in the present invention is a condition that does not require high temperature and / or high pressure utyrylthi while progressing the conversion reaction of 4-aminobutyl acid efficiently and is suitable for mass production.

Optionally, step (b) can be carried out under reduced pressure, by means of which the reduced pressure can remove the water produced during the reaction. In the present invention, the reduced pressure conditions are preferably 750 mmHg or less, more preferably 120 mmHg. Hereinafter, even more preferably 10-120 mmHg, even more preferably 10-60 mmHg, most preferably 20-60 mmHg.

Finally, 2-pyrrolidone is separated from the reaction product of step (b) to give 2-pyrrolidone in suitable purity and yield.

Separation of 2-pyrrolidone can be carried out using a variety of methods known in the art. Preferably, the separation of 2-pyrrolidone is carried out by distillation under reduced pressure. The distillation under reduced pressure is preferably 0.1-250 mmHg, more preferably 1-90 mmHg, even more preferably 1-50 mmHg, even more preferably 1-20 mmHg.

Finally, 2-pyrrolidone is obtained by high yield and high purity by the DPSP-T method of the present invention. Preferably, the process of the present invention exhibits a yield of up to 99% and a purity of up to 99.8% for 2-pyrrolidone, more preferably a yield of 90-99%, a purity of 99.0-99.8%, even more Preferably a yield of 96-99% and a purity of 99.5-99.8%.

The DPSP-P method is described in detail as follows:

According to the DPSP-P method, a reaction composition is first formed in which 4-aminobutyl acid and 2-pyrrolidone are mixed to provide a suitable environment for the conversion reaction of 4-aminobutyl acid. The process of forming the reaction composition can be described with reference to the contents described in the DPSP-T method described above.

Subsequently, the reaction composition is subjected to a heat treatment under reduced pressure to carry out a lactam cyclization reaction to generate 2-pyrrolidone and water and to remove the water. If the reaction composition of step (a) is maintained under reduced pressure at a suitable temperature, a lactam cyclization reaction takes place, converting 4-aminobutyl acid to 2-pyrrolidone and water, and water is removed from the reaction product.

One of the characteristics of the DPSP-P process is the removal of water generated during the reaction by applying a reduced pressure condition in the conversion reaction of 4-aminobutyl acid. Not only does the removal of water significantly increase the reaction rate, The reaction can proceed at low temperatures and can significantly improve the productivity for 2-pyrrolidone as a whole. In the present invention, the reduced pressure conditions are preferably 750 mmHg or less, more preferably 120 mmHg or less, even more preferably 10-120 mmHg, even more preferably 10-60 mmHg, most preferably 20-60 mmHg. The reaction temperature in step (b) is preferably at least 110 ° C. (eg 110 ° C.-150 ° C.), more preferably at least 118 ° C., even more preferably 118 ° C.-150 ° C. Optionally, 118 ° C. Even in the temperature range of -148 ° C, the present invention shows excellent yield and purity for 2-pyrrolidone. According to the present invention, 4-aminobutyl acid is converted to 2-pyrrolidone even at low temperatures of 118 ° C, for example. Can be. In step (b) the removal of water takes place. According to a preferred embodiment of the invention, the removal of water in step (b) takes place simultaneously in the course of carrying out step (b). That is, 4-aminobutyl acid is converted to 2-pyrrolidone and water, and water is removed under reduced pressure immediately after it is generated. It is preferable that such water is removed in a continuous process. Optionally, the removal of water in step (b) may be in the middle of the process of carrying out step (b). Optionally, the removal of water in step (b) may occur after carrying out step (b). .

Finally, 2-pyrrolidone is separated from the reaction product of step (b) to give 2-pyrrolidone in suitable purity and yield. Separation of 2-pyrrolidone can be described with reference to the contents described in the DPSP-T method described above.

The DPSP-P process finally yields 2-pyrrolidone in high yield and high purity. Preferably, the DPSP-P process of the present invention yields up to 99% yield and up to 99.8% for 2-pyrrolidone. Purity of 90-99%, 99.0-99.8% purity, even more preferably 96-99% yield, 99.5-99.8% purity.

The features and advantages of the present invention are summarized as follows:

(a) The present invention provides a series of processes for preparing 2-pyrrolidone from glutamic acid or glutamate using biomass.

(b) According to the present invention, 2-pyrrolidone is prepared by directly using 4-aminobutyl acid using microorganisms as whole cells, preferably 4-aminobutyl acid, which has not undergone a complicated purification process such as crystallization. It can be manufactured economically in high yield.

(c) According to the present invention, 2-pyrrolidone can be produced in large quantities in high yield and low production cost.

(d) According to the present invention, 2-pyrrolidone can be obtained in high yield and high purity from 4-aminobutyl acid without the utility of high temperature / high pressure.

(e) The present invention is suitable for mass production on an industrial scale through the simplification of the process for the production of 2-pyrrolidone.

1 shows a comparison of gamma aminobutyl acid production rates of Escherichia coli and lactic acid bacteria according to organic solvent treatment.
Figure 2 shows the change in gamma amino butyric acid production activity of the microorganism according to the organic solvent type.
Figure 3 shows the change in gamma aminobutyl acid production rate with pH. In FIG. 4, the bar graph shows the gamma aminobutyl acid production rate, and the solid line graph shows the initial pH.
Figure 4 shows the change in pH according to the reaction in high concentration GABA production using the organic solvent treated cells.

Hereinafter, the present invention will be described in more detail with reference to Examples. It is to be understood by those skilled in the art that these embodiments are only for describing the present invention in more detail and that the scope of the present invention is not limited by these embodiments in accordance with the gist of the present invention .

Example

Throughout this specification, "%" used to denote the concentration of a particular substance is intended to include solids / solids (wt / wt), solid / liquid (wt / The liquid / liquid is (vol / vol)%.

Example 1 Production of Gamma Aminobutyl Acid from Glutamic Acid or Glutamate

1-1. Production of Gamma Aminobutyl Acid from Glutamic Acid Using Various Whole Cell Catalysts Treated with Organic Solvents

Cells containing glutamic acid decarboxylase, E. coli BL21 (DE3), E. coli JM101, Lactobacillus paracasei and Lactobacillus coryniformis (KCTC) were incubated and recovered, and then divided into organic solvent treatment groups and controls. In the case of the organic solvent treatment group, the recovered cells were treated with toluene 0.5% (v / v) and stirred at 30 ° C. and 200 rpm for 10 minutes to destroy the selective permeability of microorganisms and then suspended in sterile water. The control group was immediately suspended in sterile water without any special treatment. Pyridoxal 5-phosphate (PLP, Sigma Aldrich) 40 μM was added to each of the microbial suspensions prepared above, and 33 wt% of glutamic acid (target company) was added to measure the gamma aminobutyl acid production rate. It was. To compare the experimental results, the production rate value of the experimental group without organic solvent was divided by the production rate value of the experimental group without organic solvent. As a result, as shown in Figure 1, the group treated with the organic solvent toluene was found to improve the production rate of gamma aminobutyl acid about 1.2-5.5 times than the untreated group.

1-2. Production of Gamma Aminobutyl Acid from Glutamate of Whole Cell Catalysts According to Organic Solvents

After culturing and recovering Escherichia coli containing glutamic acid decarboxylase, the rate of production of gamma aminobutyl acid from sodium glutamate (Sigma Aldrich) was analyzed after destroying the selective permeability of microorganisms using an organic solvent. . The organic solvents used were all hydrophobic organic solvents, toluene, chloroform, xylene and benzene. Treatment conditions were treated 0.5% (v / v) of each organic solvent in the microbial suspension and stirred for 10 minutes at 30 ℃, 200 rpm conditions. 40 μM of PLP was added to each of the prepared microbial suspensions, and 1% (v / v) of sodium glutamate was added to compare the gammaaminobutyl acid production rate. As a result, as shown in FIG. 2, the production rate of gamma aminobutyl acid increased about 5-8 times after hydrophobic organic solvent treatment.

1-3. Increased GABA Production Activity of Cells from Organic Solvents

The cells were recovered after incubating the Escherichia coli containing glutamic acid decarboxylase. The recovered cells were washed once with distilled water and stirred with an organic solvent to destroy the selective permeability. The organic solvent used at this time was toluene showing the fastest gamma aminobutyl acid production rate in Example 1-2. The toluene-treated experimental group and the untreated control group were divided into two groups. Toluene-treated experimental group was added with 0.5% (v / v) of toluene to the microbial suspension and stirred at 37 ° C. and 150 rpm for 10 minutes. After stirring, the cells were washed once with distilled water. The prepared cells were suspended in acetate buffer solution (pH 4.6, 200 mM), and then 0.04 mM PLP and 1% (v / v) sodium glutamate were added to measure GABA production rate. As a result, the GABA production activity of the toluene-treated cells was 5.72 μmol GABA / mg dcw / min, and the activity of the untreated cells was 0.75 μmol GABA / mg dcw / min.

1-4. Improvement of Gamma Aminobutyl Acid Production Rate According to pH of Buffer Solution

Cultivation of Escherichia coli containing glutamic acid decarboxylase and treatment of toluene, an organic solvent, in the cultured cells were carried out using the same method as described in Example 3. Suspended in sterile water. The buffer used here was all 100 mM in concentration and pH was 4.5, 6.0, 7.0 and 8.0, respectively. The preparation of the buffer solution having a pH of 4.5 was made using acetic acid, and the preparation of the buffer solution having a pH of 6.0, 7.0 and 8.0 was made of phosphoric acid. PLP 0.04 mM-addition amount was added to the suspension solution of the whole cell catalyst prepared as above, and 10 wt% glutamic acid was added thereto to initiate the reaction. Since the initial production rate of gamma aminobutyl acid was measured to analyze the change in gamma aminobutyl acid production rate according to pH. As a result, as shown in Figure 3 using a buffer solution of pH 6, when the initial pH was 3.9 the reaction rate was the maximum, the value was 116 g GABA / L / h.

1-5. GABA Production Using Cells Treated with Organic Solvents

The cells were recovered by culturing Escherichia coli containing glutamic acid decarboxylase. At this time, the amount of dry cells recovered was 3.6 g. The cells were suspended in sterile water and 0.5% (v / v) of toluene was added thereto, followed by stirring at 37 ° C for 10 minutes. After toluene treatment, the cells were recovered by centrifugation and washed once more with distilled water. The recovered cells were suspended in 2 L of phosphate buffer (pH 6.0, 100 mM), added to the reactor, and PLP 0.04 mM, 1 kg of glutamic acid and 50 ppm of an antifoaming agent (Polyoxyalkylene Glycol) were added to start the reaction. The reaction conditions were 30 ° C and 200 rpm. At the start of the reaction, the pH was 4.5 and the concentration of residual glutamic acid was reduced to less than 1 wt% after 8 hrs, at which time the pH was 5.8. Hydrochloric acid solution was added thereto to reduce the pH to 5.5, and then further reacted for 1 hr to convert all remaining glutamic acid to GABA. The total weight of GABA produced was 690 g, the molar conversion was 98% and the time taken was 9 hr in total.

1-6. Production of high concentration GABA using organic solvent treated cells

After incubating Escherichia coli containing glutamic acid decarboxylase, 0.25% (v / v) of toluene was added to the culture tank and stirred at 30 ° C for 10 minutes. After stirring, the microorganisms were recovered by centrifugation, and the weight of the dried cells was about 50 g. The microorganisms were suspended in a buffer solution or distilled water and then added to the reactor, and the reaction was started by adding 0.04 mM PLP, 8 kg of glutamic acid and 500 ppm of an antifoaming agent (Polyoxyalkylene Glycol). The reaction conditions were 30 ℃, 200 rpm, and no other elements were controlled. The pH at the start of the reaction was 4.0 and the residual glutamic acid concentration was reduced to less than 1 wt% after 10 hr of the start of the reaction, at which time the pH was 5.87. Then, the pH was reduced to 5.6 by adding hydrochloric acid solution, followed by further 2 hr reaction to convert all remaining glutamic acid to GABA (FIG. 4). The concentration of GABA produced was 34 wt%, the molar conversion was 98% and the total time spent was 12 hr.

1-7. GABA Production Using Cells Recovered after Termination of Reaction

In the same manner as in Example 1-2, the microorganism was treated with 0.5% (v / v) of toluene in 3.6 g of microorganisms, and then subjected to GABA production reaction using 0.5 kg of glutamic acid as a substrate. 9 hours after the reaction was terminated, microorganisms were recovered by centrifugation at 4000 rpm and 10 min. The cells were washed with distilled water as in Example 1, resuspended in acetic acid buffer (pH 4.6, 200 mM), and then PLP 0.04. When the GABA production activity was measured by adding mM and 1% of sodium glutamate (v / v), the value was 4.80 μmol GABA / mg dcw / min. After separating and recovering the cells used in the GABA conversion reaction, 2 g of the recovered cells were added to a reactor containing freshly prepared cells, and the conversion was again performed in the same reaction as in Example 1-2. The reaction was almost identical and the total reaction time was shortened to 6 hr.

Example  2: Obtaining Gamma Aminobutyl Acid from the Medium

The cells of the culture medium of Example 1 were removed, and heat treatment was performed to decolorize. The cells were separated by centrifugation and the heat-treated culture was decolorized with activated carbon using a stirrer. Bleaching was added 1.0-15.0% of activated carbon (weight of activated carbon / weight of gamma aminobutyl acid) to the culture. Denatured protein produced after heat treatment was filtered off with activated carbon, concentrated and used for 2-pyrrolidone synthesis. As a result, as the amount of activated carbon increased, the color of the culture tended to become transparent. Table 1 shows the activated carbon used when bleaching with activated carbon in the culture medium at the initial concentration of 30.0% (gammaaminobutyl acid weight / culture volume). The recovery rate of pyrrolidone synthesis was shown according to the concentration of activated carbon. As the concentration of activated carbon was increased, the recovery rate was decreased by increasing GABA loss rate. Pyrrolidone synthesis was carried out according to the method described in Example 3-1 below.

Activated Carbon (Activated Carbon w / GABA w%) One 2 5 10 15 2-pyrrolidone synthesis recovery 90.8 94.8
92.4 90.1 90.1

In order to minimize the loss of gamma aminobutyl acid (4-aminobutyl acid) and to most effectively remove the impurity pigments present in the culture, it was found that it is preferable to use 2.0% (weight / weight) activated carbon.

Example  3: 2- from gamma aminobutyl acid Pyrrolidone  Produce

Experimental Example : Analysis of Conversion Efficiency of Gamma Aminobutyl Acid According to Reaction Conditions

The present inventors conducted various experiments from the fact that gamma aminobutyl acid (4-aminobutyl acid) is converted to 2-pyrrolidone and water at the melting point of 202 DEG C, and as a result, 4- in the presence of 2-pyrrolidone Aminobutyl acid began to dissolve at 118 ° C-120 ° C, when the dissolved solution was found to convert to 2-pyrrolidone and water. In addition, if the water produced during the reaction was removed under reduced pressure (10-110 mmHg), the reaction time was shortened and the conversion rate of 4-aminobutyl acid to 2-pyrrolidone was also increased. It was also found that the time was shortened (Table 2-4). Table 2-4 below is a mixture of 4-aminobutyl acid and 2-pyrrolidone in a weight ratio of 1: 1 to react at 120 ° C., 130 ° C. and 140 ° C., respectively. The residual amount of 4-aminobutyric acid was analyzed by HPLC (Hewlett Packard 1050 series, Hewlett Packard). Pyrrolidone increased.

Confirmation of the residual amount of 4-aminobutyl acid (%) during the reaction at 120 ° C Reaction temperature Decompression
Condition Reaction time 2 hours 4 hours 6 hours 8 hours 10 hours 120 DEG C Atmospheric pressure 36.3% 18.4% 5.2% 1.5% 0.9% Decompression 29.4% 6.5% 1.2% 0.3% -

Remaining% of 4-aminobutyl acid during the reaction at 130 ° C. Reaction temperature Decompression
Condition Response time (hours) 1 hours 2 hours 3 hours 4 hours 5 hours 6 hours 7 hours 130 ℃ Atmospheric pressure 35.7% 25.7% 17.1% 11.1% 5.1% 2.7% 2.1% Decompression 26.8% 19.7% 8.7% 4.0% 0.9% 0.4% -

 Remaining% of 4-aminobutyl acid during the reaction at 140 ° C Reaction temperature Decompression
Condition Response time (hours) 1 hours 2 hours 3 hours 4 hours 5 hours 140 ° C Atmospheric pressure 25.7% 10.9% 1.5% 1.3% 1.2% Decompression 21.1% 0.7% 0.3% - -

3-1. 2- from 4-aminobutyl acid Pyrrolidone  Manufacture (method 1)

500 g of 2-pyrrolidone (subject) was added to a 2 L reactor equipped with a cold distillation apparatus, followed by stirring. 600 g of 4-aminobutyl acid (subject) was added thereto. (60-80 mmHg) When the temperature was raised to 135 ° C-145 ° C under stirring and 4-aminobutyl acid was dissolved, 2-pyrrolidone and water were produced. Water generated during the reaction was removed through a distillation apparatus under reduced pressure. After the reaction was completed, the residual moisture remaining in the reaction solution was removed under reduced pressure (10-20 mmHg) while gradually increasing the vacuum degree. The 2-pyrrolidone produced was then collected by distillation under reduced pressure (1-10 mmHg) to obtain colorlessness. 980 g (yield 98.5%, purity 99.5%) of high purity 2-pyrrolidone as a liquid were obtained.

3-2. 4- From aminobutyl acid  2- Pyrrolidone  Manufacture (method 2)

A 2 L reactor equipped with 1200 g of 4-aminobutyl acid and a cold distillation unit was prepared. 200 g of 4-aminobutyl acid was first introduced into a prepared 2 L reactor. The temperature of the reactor was changed to 4-aminobutyl acid. 2-pyrrolidone and water were produced as 4-aminobutyric acid melted up to (202 ° C.). 200 g of 4-aminobutyric acid was added and dissolved while naturally cooling the temperature of the reactor. 800 g of aminobutyl acid was also dissolved in the reactor at 135-145 ° C. The water produced during the reaction was removed through a distillation apparatus under atmospheric pressure or reduced pressure (40-60 mmHg). The residual water remaining in the reaction solution was removed under 20-30 mmHg while gradually increasing the vacuum degree. The 2-pyrrolidone produced was then distilled under reduced pressure (1-10 mmHg) to obtain a high-purity 2-pyrrolidone as a colorless liquid. 951 g (96% yield, purity 9 9.5%) was obtained. Even when the water produced during the reaction was removed at atmospheric pressure, 2-pyrrolidone was obtained with values similar to the above yields and purity, but the reaction time was 2 hours longer than the reduced pressure conditions. .

3-3. 4- From aminobutyl acid2 - Pyrrolidone  Manufacture (method 3)

1200 g of 4-aminobutyl acid was added to a 2 L reactor equipped with a cold distillation unit while the stirrer was stopped. When the temperature of the reactor was raised to 200 ° C-210 ° C, some 4-aminobutyl acid was dissolved and 2-pyrroli Money and water were produced. The stirrer was started slowly and the stirring condition was checked and stirring was started if possible. The stirring was allowed to naturally cool the reactor temperature, and the remaining 4-aminobutyl at the reactor temperature of 135-145 ° C. The acid was dissolved. The water produced during the reaction was removed through a distillation apparatus under atmospheric pressure or 40-60 mmHg. When the reaction solution became transparent, the reaction was terminated, so that the residual water remaining in the reaction solution under reduced pressure was gradually removed while increasing the vacuum degree. The resulting 2-pyrrolidone was distilled under reduced pressure (1-10 mmHg) to give 960 g (yield 96.9%, purity 99.5%) of a high purity 2-pyrrolidone as a colorless liquid. Even if removal of the water produced at atmospheric pressure, with approximately the same value as the yield and purity of the above obtained but a 2-pyrrolidone, the reaction time is no longer than 2 hours under reduced pressure conditions.

3-4. 4- From aminobutyl acid2 - Pyrrolidone  Produce

500 g of 2-pyrrolidone was added to a 2 L reactor equipped with a cold distillation apparatus and stirred. Here, 600 g of 4-aminobutyric acid was added. The temperature was raised to 118 ° C. to 120 ° C. and about 10 hours at this temperature. A sample of the reaction solution was taken and analyzed by HPLC to determine 0.9% of the residual concentration of 4-aminobutyl acid and the reaction was terminated. The resulting water was removed through a distillation apparatus under 20-30 mm Hg. Then, 2-pyrrolidone remaining in the reactor was collected by distillation under reduced pressure (1-10 mmHg) to obtain 974 g (yield 97.9%, purity 99.4%) of a high purity 2-pyrrolidone as a colorless liquid.

3-5. 4- From aminobutyl acid2 - Pyrrolidone  Produce

500 g of 2-pyrrolidone was added to a 2 L reactor equipped with a cold distillation apparatus, followed by stirring. Here, 600 g of 4-aminobutyl acid was added thereto. After the reaction was carried out, the 4-aminobutyl acid was dissolved to produce 2-pyrrolidone and water. The generated water was removed through a distillation apparatus under reduced pressure. After about 8 hours, a sample of the reaction solution was taken and analyzed by HPLC. The reaction was terminated after confirming the residual concentration of 4-aminobutyric acid 0.3%. The vacuum of the reaction solution was gradually increased to completely remove residual moisture. Thereafter, 2-pyrrolidone remaining in the reactor was distilled off under reduced pressure (1). -10 mmHg) to give 985 g (yield 99%, purity 99.8%) of a high purity 2-pyrrolidone as a colorless liquid.

3-6. 4- From aminobutyl acid2 - Pyrrolidone  Produce

500 g of 2-pyrrolidone was added to a 2 L reactor equipped with a cold distillation apparatus and stirred. Here, 600 g of 4-aminobutyric acid was added. The temperature was reduced to 128 ° C.-132 ° C. under reduced pressure (30-50 mmHg). After the reaction was carried out, the 4-aminobutyl acid was dissolved to produce 2-pyrrolidone and water. The generated water was removed through a distillation apparatus under reduced pressure. After about 8 hours, a sample of the reaction solution was taken and analyzed by HPLC. After confirming the residual concentration of 4-aminobutyl acid at 0.4%, the reaction was terminated. The remaining liquid was completely removed while gradually increasing the vacuum of the reaction solution. Thereafter, 2-pyrrolidone remaining in the reactor was distilled under reduced pressure (1). -10 mmHg) was collected to give 980 g (yield 98.5%, purity 99.6%) of high purity 2-pyrrolidone as a colorless liquid.

3-7. 4- From aminobutyl acid2 - Pyrrolidone  Produce

500 g of 2-pyrrolidone was added to a 2 L reactor equipped with a cold distillation apparatus, followed by stirring. Here, 600 g of 4-aminobutyl acid was added thereto. The temperature was reduced to 138 ° C.-142 ° C. under reduced pressure (60-80 mmHg). After the reaction was carried out, the 4-aminobutyl acid was dissolved to produce 2-pyrrolidone and water. The generated water was removed through a distillation apparatus under reduced pressure. After about 3 hours, a sample of the reaction solution was taken and analyzed by HPLC. The reaction was terminated after confirming the residual concentration of 4-aminobutyric acid 0.3%. The vacuum of the reaction solution was gradually increased to completely remove residual moisture. Thereafter, 2-pyrrolidone remaining in the reactor was distilled under reduced pressure (1). -10 mmHg) was collected to obtain 985 g (yield 99%, purity 99.1%) of high purity 2-pyrrolidone as a colorless liquid.

3-8. 4- From aminobutyl acid2 - Pyrrolidone  Produce

500 g of 2-pyrrolidone was added to a 2 L reactor equipped with a cold distillation apparatus and stirred. 600 g of 4-aminobutyl acid was added thereto. The temperature was reduced from 145 ° C to 148 ° C under reduced pressure (70 to 110 mmHg). After the reaction was carried out, the 4-aminobutyl acid was dissolved to produce 2-pyrrolidone and water. The produced water was removed through a distillation apparatus under reduced pressure. After about 2 hours, a sample of the reaction solution was taken and analyzed by HPLC. The reaction was terminated after confirming the residual concentration of 4-aminobutyric acid 0.3%. The vacuum of the reaction solution was gradually increased to completely remove residual moisture. Thereafter, 2-pyrrolidone remaining in the reactor was distilled under reduced pressure (1). -10 mmHg) was collected to give 978 g (yield 98.3%, purity 99.3%) of high purity 2-pyrrolidone as a colorless liquid.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the same is by way of illustration and example only and is not to be construed as limiting the scope of the present invention. It is therefore intended that the scope of the invention be defined by the claims appended hereto and their equivalents.

Claims (8)

Method for preparing 2-pyrrolidone, comprising the following steps:
(a) culturing a microorganism containing glutamate decarboxylase as a whole-cell catalyst in a medium containing glutamic acid or glutamate to produce 4-aminobutyl acid;
(b) obtaining the 4-aminobutyl acid from the medium by filtration; And
(c) converting the 4-aminobutyl acid to 2-pyrrolidone.
The method of claim 1, wherein the microorganism is a microorganism pretreated with a hydrophobic organic solvent.
The method of claim 1, wherein step (a) is carried out in the range of pH 3.0-8.0 buffer area.
The method of claim 1, further comprising the step of removing activated pigment from the medium by treating the medium with activated carbon between steps (a) and (b).
5. The method according to claim 4, wherein the activated carbon is added at 1.5-4.0 wt% based on the weight of 4-aminobutyl acid in the medium.
The method of claim 1, further comprising, after step (b), separating the whole cell catalyst and reusing the separated whole cell catalyst.
The method of claim 1 wherein the 4-aminobutyl acid used in step (c) is not pre-purified.
The method of claim 1, wherein step (c) comprises the following substeps:
(c-1) forming a reaction composition in which 4-aminobutyl acid and 2-pyrrolidone are mixed;
(c-2) heat treating the reaction composition to perform a lactam cyclization reaction to produce 2-pyrrolidone and water; And
(c-3) separating the 2-pyrrolidone.

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