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Method used for smooth and steady preparation of 2-methoxypropandioic acid ethyl methyl ester

A technology of methyl ethyl methoxymalonate and methyl methoxy acetate, which is applied in the field of preparation of sulfonamide intermediates, can solve problems such as danger, temperature rise, unfavorable safety management of production workshops, etc., and achieve improvement Yield, reduce the intensity of the reaction, reduce the effect of side reactions

Inactive Publication Date: 2014-07-09
CHANGSHU NANHU INDAL CHEM
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Problems solved by technology

However, under the action of solid sodium methoxide, methyl methoxyacetate and diethyl oxalate react violently and release a large amount of heat, which can easily lead to a sharp rise in the temperature in the reactor, resulting in danger, which is not conducive to the safety management of the production workshop

Method used

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  • Method used for smooth and steady preparation of 2-methoxypropandioic acid ethyl methyl ester
  • Method used for smooth and steady preparation of 2-methoxypropandioic acid ethyl methyl ester
  • Method used for smooth and steady preparation of 2-methoxypropandioic acid ethyl methyl ester

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Embodiment 1

[0033] This example provides a kind of method for stably preparing methyl ethyl methoxymalonate, and specific feeding ratio is as shown in Table 1:

[0034] Table 1 Reaction raw materials and their feeding ratio

[0035]

[0036] The specific operation process is as follows:

[0037] (a) 175kg of methyl methoxyacetate and 150kg of diethyl oxalate are put into a pre-dried mixed ester pot, stirred and mixed, and cooled to below 10°C, and put into a pre-dried Kjeldahl reaction kettle;

[0038] (b) Disperse 130kg of solid sodium ethylate in 150kg of diethyl oxalate, drop it into the above-mentioned Kjeldahl reaction kettle at a rate of 10 drops / second (the dropping time is controlled within 1 to 2 hours), and control the reaction liquid The temperature is between 50 and 60°C, and the reaction is kept for 4 hours;

[0039] (c) Add 280L trichlorethylene in advance in the dilution pot and cool it to below 20°C, then pour the reaction pressure in the Kjeldahl reaction pot into th...

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Abstract

The invention relates to a method used for smooth and steady preparation of 2-methoxypropandioic acid ethyl methyl ester. The method comprises following steps: (a) methyl methoxyacetate and diethyl oxalate are delivered into a reaction container, and a mixed solution is obtained via mixing; (b) solid sodium methylate is dispersed in diethyl oxalate, an obtained mixture is added into the mixed solution dropwise, and an obtained mixed material is reacted for 2 to 8h at a temperature of 50 to 60 DEG C so as to obtain a reaction liquid; (c) an organic solvent, water, and an acid solution are delivered into another reaction container for mixing, the reaction liquid is added, a temperature of an obtained material is controlled below 15 DEG C, pH value is adjusted to 1 to 2, and the material is allowed to stand so as to obtain a water layer and an organic solvent layer; (d) the organic solvent layer is collected and is subjected to distillation so as to remove the organic solvent, and an obtained product is subjected to decarbonylation at a temperature of 178 to 182 DEG C under a vacuum degree of -0.04 to -0.053MPa for 2 to 6h, and fractions obtained under a vacuum degree of -0.095MPa at a temperature above 170 DEG C are collected. According to the method, solid sodium methylate is dispersed in diethyl oxalate which is not too active, and then the obtained mixture is added into the mixed solution dropwise, so that reaction fierce degree of the whole system after adding of solid sodium methylate can be reduced effectively, and smoothness of the reaction is ensured.

Description

technical field [0001] The invention relates to a preparation method of a sulfonamide intermediate, in particular to a method for stably preparing methylethyl methoxymalonate. Background technique [0002] Sulfonamide, whose chemical name is 4-(p-aminobenzenesulfonyl)-5,6-dimethoxypyrimidine, is generally used for the treatment of inflammation, such as upper respiratory tract infection tonsillitis, bacillary enteritis, skin infection, etc. It can be used in conjunction with other drugs to treat pulmonary tuberculosis and lymphatic tuberculosis. Sulfonamide has gone through several generations of research and development, and its production process has gradually stabilized, specifically the following preparation steps: [0003] step 1): [0004] [0005] Step (2): [0006] [0007] Step (3): [0008] [0009] Step (4): [0010] [0011] [0012] Step (5): [0013] [0014] Wherein, methyl ethyl methoxymalonate is the intermediate prepared in the step ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C69/708C07C67/333
CPCC07C67/317C07C67/333C07F1/04C07C69/708C07C69/716
Inventor 邵香民
Owner CHANGSHU NANHU INDAL CHEM
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