Theanine preparing process

A technology of theanine and pyroglutamic acid, which is applied in the direction of organic chemistry, can solve the problems of large investment in equipment and high requirements for reaction conditions, and achieve the effect of small investment in equipment, low requirements for reaction conditions, and low production costs

Inactive Publication Date: 2005-12-14
郑国斌
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Problems solved by technology

[0005] In the patent application number 02134857.X, a method for preparing theanine by reacting L-pyrrolidone acid and pure ethylamine in an atmosphere of inert gas is disclosed, the pressure is controlled at 6Mpa-12Mpa, and the reaction temperature is controlled at 60°C ~100°C, this preparation method requires high reaction conditions and equipment investment

Method used

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example 1

[0018] Step 1: Put 50kg of L-pyroglutamic acid and 100kg of anhydrous ethylamine into a 200-liter reactor. In a closed state, stir and heat up. The temperature is controlled at about 35°C and the pressure is about 2.5Mpa. React 96 Hours, after the reaction is over, distill and recover ethylamine in a vacuum state, add absolute ethanol after cooling to room temperature, stir and heat up to reflux for 50 minutes, cool to 10°C to crystallize, and centrifuge to obtain L-theanine The crude product is about 15kg (wet product).

[0019] Step 2: Put 15kg of the L-theanine crude product obtained in step 1 and 120kg of absolute ethanol into a 200-liter reactor, the weight ratio of the two is 1:8, heat up to reflux for 50 minutes under stirring, and cool to 10°C, centrifuge to remove the material, and dry to obtain about 10kg of L-theanine high-quality goods. Calculated by solid L-pyroglutamic acid, the yield of L-theanine refined product is about 20%, and the purity of the obtained pro...

example 2

[0021] Step 1: Put 50kg of L-pyroglutamic acid and 200kg of anhydrous ethylamine into a 500-liter reactor, heat up in a closed state with stirring, and control the temperature between 50 and 55°C. Between 4 and 4.5Mpa, react for about 72 hours. After the reaction is over, distill and recover ethylamine to dryness under vacuum. After cooling to room temperature, add absolute ethanol, stir and heat up to reflux for 30 minutes, and cool to 5°C to crystallize , and centrifuged to get about 16kg of L-theanine crude product (wet product).

[0022] Step 2: Put 16kg of the L-theanine crude product obtained in step 1 and 80kg of absolute ethanol into a 200-liter reactor, the weight ratio of the two is 1:5, heat up to reflux under stirring, and cool to reflux for 50 minutes. Centrifuge at 5°C and dry to obtain about 11kg of fine L-theanine.

[0023] Calculated by solid L-pyroglutamic acid, the yield of L-theanine refined product is about 22%, and the purity is above 98%, which is deter...

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Abstract

The present invention provides theanine preparing process. Under closed condition, L-pyroglutamic acid and anhydrous ethylamine react directly to produce theanine at temperature of 30-55 deg.c and pressure of 2-4 MPa. The preparation process uses marketable materials, and has safe and relaxed reaction condition, product yield over 20 %, product purity over 98 %, low production cost, less investment in apparatus, and is suitable for industrial production. What is more important is that all the side products of different steps may be reused in the next circulation, resulting in high comprehensive utilization and few environmental pollution.

Description

Technical field: [0001] The invention relates to a preparation method of theanine. Background technique: [0002] L-theanine (L-thiamine) is a characteristic amino acid of tea, which has various edible and medicinal functions. Its scientific name is N-ethyl-L-glutamine (N-ethyl-Lglutamine), and its structural formula is as follows: [0003] [0004] In 1942, Israeli Liechtenstein first used ethylamine and pyrrolidone acid to react in aqueous solution to obtain theanine in the laboratory. In 1951, Japan invented a method of using L-pyrrolidone acid and pure ethylamine (instead of dissolving in water) to react at low temperature, and the yield of theanine was increased, but the reaction time required a week or less. More than ten days, or even longer. [0005] In the patent application number 02134857.X, a method for preparing theanine by reacting L-pyrrolidone acid and pure ethylamine in an atmosphere of inert gas is disclosed, the pressure is controlled at 6Mpa-12Mpa, a...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C237/06
Inventor 郑国斌
Owner 郑国斌
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