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Method for synthesizing diethoxymethane through continuous heterogeneous tubular reaction

A diethoxymethane, tubular reaction technology, applied in chemical instruments and methods, preparation of organic compounds, organic compound/hydride/coordination complex catalysts, etc., can solve harsh reaction conditions, long reaction time, The problem of strong corrosion of equipment, etc., achieves the effect of continuous reaction process, short reaction time and no corrosion of equipment

Pending Publication Date: 2020-07-17
NANJING NORMAL UNIVERSITY
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] At present, there are mainly the following five methods to synthesize diethoxymethane: (1) Dichloromethane method, using dichloromethane and sodium ethylate as reaction raw materials, and the reaction temperature is 50 ° C. This method is the earliest method for synthesizing diethoxymethane. method, but due to the existence of sodium ethylate, the reaction conditions are required to be anhydrous operation, the reaction conditions are relatively harsh, and the DEM yield is low, so it is rarely used
(2) Dimethyl sulfoxide method, using ethanol and dimethyl sulfoxide as reaction raw materials, using polyphosphoric acid as a catalyst to synthesize diethoxymethane, wherein dimethyl sulfoxide is decomposed under the catalysis of polyphosphoric acid to provide formaldehyde, formaldehyde and Ethanol reacts to form diethoxymethane; because this method requires a large amount of dimethyl sulfoxide and the product yield is not high, it is difficult to use in large-scale production of diethoxymethane
(3) calcium chloride method, adopt formaldehyde and ethanol as reaction raw material, take calcium chloride as catalyst synthesis diethoxymethane, this reaction yield is higher, but reaction time is longer, is unfavorable for large-scale production, and reaction Afterwards, the catalyst needs to be post-treated, and the process flow is cumbersome
(4) chloramphenicol by-product method, in the production process of chloramphenicol, there is the urotropine solution of p-nitro-2-bromoacetophenone to generate, add hydrochloric acid and ethanol mixed solution in this solution, obtain By-product diethoxymethane, but the limited output of this method is not conducive to industrialized large-scale production; (5) acid catalysis method, adopting formaldehyde and ethanol as reaction raw materials, taking concentrated hydrochloric acid as catalyst to synthesize diethoxymethane, this reaction operation The method is simple, the reaction time is short and the yield is high. It is a relatively ideal method for synthesizing diethoxymethane, but there are also some defects, such as strong corrosion to equipment, and the need to neutralize the product.

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  • Method for synthesizing diethoxymethane through continuous heterogeneous tubular reaction
  • Method for synthesizing diethoxymethane through continuous heterogeneous tubular reaction
  • Method for synthesizing diethoxymethane through continuous heterogeneous tubular reaction

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Experimental program
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Effect test

Embodiment 1

[0034]First take by weighing 2.5g self-made polystyrene base sulfonic acid resin catalyst, fill in the heterogeneous tubular reactor, then ethanol (95%wt) and formaldehyde aqueous solution (37%wt) according to aldol molar ratio 3:1 The proportion of the mixed solution is made into a mixed solution; the mixed liquid is injected into the preheater at a certain rate through a peristaltic pump, and the temperature of the preheater is set at 80°C. within 1°C). The reaction pressure is normal pressure; a storage tank is used at the sampler at the lower end of the condenser to receive the condensed liquid after the reaction. Table 1 shows the influence of different feed rates on the conversion and selectivity of diethoxymethane.

[0035] Table 1 Effect of feed rate on conversion and selectivity of diethoxymethane synthesis reaction

[0036]

[0037]

[0038] It can be seen from Table 1 that under the reaction parameters of aldol-aldehyde molar ratio of 3:1, reaction temperatu...

Embodiment 2

[0040] First take by weighing 2.5g self-made polystyrene base sulfonic acid resin catalyst, fill in the heterogeneous tubular reactor, then ethanol (95%wt) and formaldehyde aqueous solution (37%wt) according to aldol molar ratio 3:1 The proportion of the mixed solution is made into a mixed solution; the mixed liquid is injected into the preheater at 0.10ml / min through a peristaltic pump, and the temperature of the preheater is set to the corresponding reaction temperature. By adjusting the set temperature of the reactor, the reaction temperature measurement is kept stable at a certain Temperature (up and down within 1°C). The reaction pressure is normal pressure; a storage tank is used at the sampler at the lower end of the condenser to receive the condensed liquid after the reaction. The influence of different reaction temperatures on the conversion and selectivity of diethoxymethane is shown in Table 2.

[0041] Table 2 Effect of reaction temperature on the conversion and s...

Embodiment 3

[0045] First take by weighing 2.5g self-made polystyrene base sulfonic acid resin catalyst, fill in the heterogeneous tubular reactor, then ethanol (95%wt) and formaldehyde aqueous solution (37%wt) according to aldol molar ratio 3:1 The proportion of the mixed solution is made into a mixed solution; the mixed liquid is injected into the preheater at 0.10ml / min through a peristaltic pump, and the temperature of the preheater is set at 75°C. By adjusting the set temperature of the reactor, the reaction temperature measurement is maintained at 75°C error within 1°C). The reaction pressure is set to different values; a storage tank is used to receive the condensed liquid after the reaction at the sampler at the lower end of the condenser. The influence of different reaction pressures on the conversion and selectivity of diethoxymethane is shown in Table 3.

[0046] Table 3 Effect of reaction pressure on the conversion and selectivity of the synthesis of diethoxymethane

[0047] ...

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Abstract

The invention discloses a method for synthesizing diethoxymethane through a continuous heterogeneous tubular reaction. The method comprises the steps: by taking polystyrene-based sulfonic acid type resin as a catalyst, a heterogeneous tubular reactor as a reaction device and formaldehyde and ethanol as reaction raw materials, enabling the formaldehyde and ethanol to flow through the polystyrene-based sulfonic acid type resin catalyst in the reaction device, and carrying out continuous reaction to prepare diethoxymethane. The method provided by the invention has the characteristics of continuous reaction process, short reaction time, high conversion rate, good selectivity, easy control of product quality and the like. Compared with the use of an inorganic acid catalyst, the reaction productdoes not need neutralization and does not corrode equipment.

Description

technical field [0001] The invention discloses a method for synthesizing diethoxymethane through continuous heterogeneous tubular reaction, belonging to the technical field of diethoxymethane preparation. Background technique [0002] Diethoxymethane is a chemical raw material with excellent performance and a wide range of uses. It is also called methylal diethanol, formaldehyde ester, etc., and the English abbreviation is: DEM. Its molecular structure is CH 3 CH 2 OCH 2 OCH 2 CH 3 , From the structural point of view, diethoxymethane is equivalent to a kind of cell diether, so it has an ether-like smell. From the perspective of organic matter classification, diethoxymethane is a kind of acetal, which is relatively stable to alkaline solution, but it is easily hydrolyzed into formaldehyde in acidic aqueous solution under warm conditions. Based on this feature, diethoxymethane is often used as For organic synthesis reactions in alkaline solution. In appearance, diethoxy...

Claims

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Application Information

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IPC IPC(8): C07C41/56C07C43/30B01J31/10B01J8/06
CPCC07C41/56B01J31/10B01J8/06C07C43/30
Inventor 顾正桂费维民汪凯军曹晓艳
Owner NANJING NORMAL UNIVERSITY