Continuous synthesis method of ethoxymethylene malononitrile

A technology of ethoxymethylene malononitrile and synthesis method, which is applied in chemical instruments and methods, preparation of carboxylic acid nitrile, preparation of organic compounds, etc., and can solve the problems of low yield, environmental safety of toxic solvent pollution, etc. , to achieve the effects of increased yield, reduced high-temperature dangerous area, and avoided decomposition of raw materials

Active Publication Date: 2020-04-28
ASYMCHEM LAB TIANJIN
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Problems solved by technology

[0008] The main purpose of the present invention is to provide a kind of continuous synthesis method of ethoxymethylene malononitrile, to solve the low yield, toxic solvent pollution environment and safety when preparing ethoxymethylene malononitrile in the prior art. sex problem

Method used

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  • Continuous synthesis method of ethoxymethylene malononitrile

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preparation example Construction

[0022] In order to solve the above problems, the invention provides a continuous synthesis method of ethoxymethylene malononitrile, which comprises the following steps: malononitrile, triethyl orthoformate and acetic anhydride are continuously passed into the continuous reaction equipment Carry out substitution reaction in, obtain ethoxymethylene malononitrile, and in the process of substitution reaction, the ethoxymethylene malononitrile of generation discharges continuously; Wherein, malononitrile, triethyl orthoformate The molar ratio with acetic anhydride is 1:(0.9~6.0):(2.0~6.0).

[0023] The invention realizes the continuous production of ethoxymethylene malononitrile through the continuous substitution reaction of malononitrile, triethyl orthoformate and acetic anhydride by adopting continuous reaction equipment. Compared with the traditional kettle reaction, since the amount of materials participating in the reaction per unit time is greatly reduced, the high temperatu...

Embodiment 1

[0035]

[0036] The feeding amount is 1.0kg, under room temperature, malononitrile (1.0kg, 15.14mol) and acetic anhydride (3.25kg, 31.79mol) are mixed uniformly, and it is recorded as material A; triethyl orthoformate (2.47kg, 16.65mol) is recorded as for material B. Pump A speed is: 248g / min, pump B speed is: 157g / min, material A and material B are pumped in the continuous pipeline reactor (volume is 50L) with pump respectively, temperature control 120 ℃, continuous reactor outlet is prepared The pressure is 0.3~0.5MPa, the residence time is 100min, and the outlet sample is analyzed by GC, and the remaining raw material is 0.0~0.5%. Concentrate the system flowing out of the continuous reactor to 6V under vacuum, control the temperature at 20-30°C, and add 4V n-heptane dropwise to the above system. After the dropping is complete, a large amount of solids are precipitated out of the system. Filtration and drying of the solids gave 1.83 kg of the product ethoxymethylenemalon...

Embodiment 2

[0038] Pump A system is malononitrile (100g, 1.51mol) + acetic anhydride (325g, 3.18mol), pump B is triethyl orthoformate (247g, 1.67mol), pump A speed is: 24.8g / min, pump B The speed is: 15.7g / min. Simultaneously turn on pump A and pump B to pump two streams of raw materials into the continuous reactor (volume 5L), control the temperature at 130°C, prepare the pressure at the outlet of the continuous reactor at 0.3-0.5MPa, and keep the residence time at 100min. Take samples from the outlet for GC analysis. The remaining raw material is 0.0-0.5%. The outflowing system is concentrated, concentrated to 6V, added dropwise with 4V n-heptane for crystallization, and filtered to obtain 165.0g of the product ethoxymethylenemalononitrile, GC purity: 97.2%, Yield 79.8%.

[0039] The difference from Example 1: the reaction temperature is 130°C.

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Abstract

The invention provides a continuous synthesis method of ethoxymethylene malononitrile. The method comprises the following steps: continuously introducing malononitrile, triethyl orthoformate and acetic anhydride into continuous reaction equipment for substitution reaction to obtain ethoxymethylene malononitrile, and continuously discharging the generated ethoxymethylene malononitrile in the substitution reaction process, wherein the molar ratio of malononitrile to triethyl orthoformate to acetic anhydride is 1: (0.9-6.0): (2.0-6.0). The continuous reaction equipment is adopted, and the quantity of materials participating in the reaction in unit time is greatly reduced so that a high-temperature dangerous area is reduced and the safety risk is greatly reduced. The raw materials can be instantly heated to the reaction temperature through the continuous reactor, raw material decomposition caused by the long-time heating process is avoided, and the yield is remarkably increased. In addition, secondary toxic solvents such as methylbenzene are not needed in the reaction process.

Description

technical field [0001] The invention relates to the technical field of organic synthesis, in particular to a continuous synthesis method of ethoxymethylene malononitrile. Background technique [0002] Ethoxymethylene malononitrile is white to off-white crystalline powder, insoluble in water, soluble in organic solvents such as methanol and ethanol, with a melting point of 65-67°C and a boiling point of 160°C (12mmHg), and is often used in the preparation of industrial chemicals 1. Intermediates of pharmaceutical chemicals, such as intermediates for the preparation of milrinone. Therefore, ethoxymethylene malononitrile has an extremely broad field and very broad development prospects, and it is of great significance to develop a high-efficiency, low-cost ethoxymethylene malononitrile synthesis process. [0003] At present, the preparation method of ethoxymethylene malononitrile comprises the following steps: triethyl orthoformate and malononitrile are refluxed until the reac...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C253/30C07C255/15
CPCC07C253/30C07C255/15
Inventor 洪浩卢江平包登辉刘超杰贾晓童
Owner ASYMCHEM LAB TIANJIN
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