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Synthetic method of 2, 3-dibromo-2-methylpropanoic acid

A technique for the synthesis of methacrylic acid, which is applied in chemical instruments and methods, carboxylate preparation, organic compound preparation, etc., can solve the problems of harm to the human body and the environment, low yield, and potential safety hazards, and achieve operational Simple and convenient, high yield, avoiding the effect of harm

Inactive Publication Date: 2009-10-21
ZHEJIANG UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0007] In the above two synthesis processes, route 1 does not use a solvent, but the yield is low, only 77%, and there are many inconveniences in production, such as a large amount of solids are generated in the late stage of the reaction, stirring is difficult, heat transfer Poor mass transfer, difficult to normal industrial production
while route 2 is in CS 2 2,3-dibromo-2-methylpropionic acid was synthesized in a solvent, and a higher yield of 90% was achieved, but the CS 2 Strong toxicity, harmful to human body and environment; In addition, CS 2 The ignition point is low, there is a great potential safety hazard, and it is very inconvenient to use in industry

Method used

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Examples

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Effect test

Embodiment 1

[0020] Embodiment 1, a kind of synthetic method of 2,3-dibromo-2-methyl propionic acid, take methacrylic acid and bromine as raw material, carry out following steps successively:

[0021] 1) Weigh methacrylic acid (40g, 0.4646mol) into a three-necked flask, add 40ml of water, heat up to 100°C under stirring, add bromine (74.4g, 0.4646mol) dropwise, drop it in about 30 minutes, continue to React at 100°C for 1 h; after the reaction, the crude product of 2,3-dibromo-2-methylpropionic acid was obtained.

[0022] 2), the above crude liquid is cooled to below 5°C (for example, 0°C) for crystallization, and then suction filtered to obtain the mother liquor and solid; the above solid is washed with cold water for 2 to 3 times, and after drying, 113g of light yellow solid is obtained. The light yellow solid is 2,3-dibromo-2-methylpropionic acid with a purity of 99.5% and a melting point of 46-48°C. The yield was 98.8%.

Embodiment 2

[0023] Embodiment 2, a kind of synthetic method of 2,3-dibromo-2-methyl propionic acid, take methacrylic acid and bromine as raw material, carry out the following steps successively:

[0024] 1) Weigh methacrylic acid (40g, 0.4646mol) into a three-necked flask, add 160ml of water, heat up to 75°C under stirring, add bromine (74.4g, 0.4646mol) dropwise, drop it in about 30 minutes, continue to Reaction at 75°C for 3h; after the reaction, the crude product of 2,3-dibromo-2-methylpropionic acid was obtained.

[0025] 2), cooling the above crude liquid to below 5°C (for example, 0°C) for crystallization, and then suction filtration to obtain the mother liquor and solid; washing the above solid with cold water for 2 to 3 times, and drying to obtain 111g of light yellow solid, the The light yellow solid is 2,3-dibromo-2-methylpropionic acid with a purity of 99.8% and a melting point of 46-47°C. The yield was 97.1%.

Embodiment 3

[0026] Embodiment 3, a kind of synthetic method of 2,3-dibromo-2-methyl propionic acid, take methacrylic acid and bromine as raw material, carry out the following steps successively:

[0027] 1) Weigh methacrylic acid (40g, 0.4646mol) into a three-necked flask, add 320ml ml water, heat up to 75°C under stirring, add bromine (223.2g, 1.3938mol) dropwise, drop it in about 30 minutes, continue React at 75°C for 1 h; after the reaction, the crude product of 2,3-dibromo-2-methylpropionic acid is obtained.

[0028] 2), cooling the above crude liquid to below 5°C (for example, 0°C) for crystallization, and then suction filtration to obtain the mother liquor and solid; washing the above solid with cold water 2 to 3 times, and drying to obtain 113.2 g of light yellow solid, The light yellow solid is 2,3-dibromo-2-methylpropionic acid with a purity of 99.6% and a melting point of 46-48°C. The yield was 99%.

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Abstract

The invention discloses a synthetic method of 2, 3-dibromo-2-methylpropanoic acid, which takes methacrylic acid and bromine as raw materials and comprises the following steps of: 1) adding bromine into methacrylic acid water solution, reacting for 1h to 5h at the temperature of 50 to 100 DEG C, and obtaining crude product solution of 2, 3-dibromo-2-methylpropanoic acid; wherein the mol ratio of methacrylic acid and bromine is 1: 1 to 1: 3; 2) obtaining mother liquid and solid by carrying out temperature reduction and crystallization, and filtration; and 3) obtaining the 2, 3-dibromo-2-methylpropanoic acid by washing the solid for 2 to 3 times, and drying. The method for producing 2, 3-dibromo-2-methylpropanoic acid has the advantages of high yield coefficient, environmental protection and the like.

Description

technical field [0001] The invention relates to a chemical synthesis method, in particular to a method for synthesizing 2,3-dibromo-2-methylpropionic acid in water phase. Background technique [0002] 2,3-Dibromo-2-methylpropionic acid is a synthetic intermediate of β-lactam antibiotics, and its structural formula is as follows: [0003] [0004] Reported in the literature 2, the synthetic technique of 3-dibromo-2-methyl propionic acid comprises following two kinds: [0005] 1. In 1982, when Okawara was synthesizing the antibiotic β-lactam, he used methacrylic acid and bromine addition to synthesize 2,3-dibromo-2-methylpropionic acid without solvent, and the yield was 77%; [0006] 2. In 1989, David G and others put methacrylic acid in CS 2 Carry out bromine addition in , obtain 2,3-dibromo-2-methylpropionic acid, the yield is 90%; [0007] In the above two synthesis processes, route 1 does not use a solvent, but the yield is low, only 77%, and there are many inconven...

Claims

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Application Information

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IPC IPC(8): C07C53/19C07C51/363
Inventor 陈新志曹长辉钱超
Owner ZHEJIANG UNIV
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