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A kind of method of efficient rectification production tetraethyl orthocarbonate

A technology of tetraethyl orthocarbonate and rectification, applied in chemical instruments and methods, preparation of organic compounds, organic chemistry, etc., can solve the problems of waste of resources, unsafe handling, aggravated product hydrolysis, etc., and achieve high-efficiency rectification, The effect of raising pH

Active Publication Date: 2020-10-09
GENCHEM & GENPHARM CHANGZHOU CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

This method has following shortcoming in industrial-scale production: (1) use strong oxidizing agent such as hydrogen peroxide, the cyanide in sodium hypochlorite treatment water is violent exothermic reaction, and with a large amount of gas emission, processing is unsafe in industrial-scale device; (2 ) Cyanide is also an available resource, which is completely destroyed by oxidation and cannot be used, which is a waste of resources
Due to the characteristics of tetraethyl orthocarbonate, it is easy to hydrolyze under neutral or weakly acidic conditions, and the hydrolyzed product has a certain acidity to further aggravate the hydrolysis of the product; due to the use of ethanol in the production process, the crude product to be rectified has a high water content, and rectification In the process, the product is continuously degraded under the action of water, and it is difficult to obtain a high-purity product. At present, the purity of tetraethyl orthocarbonate is generally between 98% and 99%. With the development of modern medicine in recent years, the quality of tetraethyl orthocarbonate The requirements are getting higher and higher, and tetraethyl orthocarbonate with a purity of 98%-99% can no longer fully meet the needs of the market

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0024] (1) drop into 320kg of sodium ethylate, 1280kg of dehydrated alcohol to the reactor of clean, dry 2000L;

[0025] (2) Control the temperature between 65° C. and 70° C., add 97 kg of trichloropicrin dropwise, continue the heat preservation reaction for 3 hours after the addition, and recover 900 kg of absolute ethanol by atmospheric distillation;

[0026] (3) add water 1600kg, all residues are dissolved, add n-heptane 1280kg to extract;

[0027] (4) The organic phase enters the rectifying tower, adds sodium ethylate 0.05kg, and the normal pressure control reflux ratio is 1~2, and first normal pressure steams out normal heptane 1024kg;

[0028] (5) control the reflux ratio again to be 3~5, rectify product tetraethyl orthocarbonate under the pressure of-0.098MPa, obtain product altogether: 104kg, purity 99.7%, single impurity<0.1%, yield 91%.

Embodiment 2

[0030] (1) drop sodium ethylate 320kg, dehydrated alcohol 1600kg into clean, dry 2000L reactor;

[0031] (2) Control the temperature between 65° C. and 68° C., add 91.4 kg of trichloropicrin dropwise, continue the insulation reaction for 3 hours after the addition, and recover 1120 kg of absolute ethanol by atmospheric distillation;

[0032] (3) add 1920kg of water, all residues are dissolved, add n-heptane 1280kg to extract;

[0033] (4) The organic phase enters the rectifying tower, adds sodium ethylate 0.5kg, and the normal pressure control reflux ratio is 1~2, first normal pressure steams 896kg of n-heptane;

[0034] (5) control the reflux ratio again to be 4~6, rectify product tetraethyl orthocarbonate under the pressure of-0.095MPa, obtain product altogether: 102kg, purity 99.7%, single impurity<0.1%, yield 90%.

Embodiment 3

[0036] (1) drop into 320kg of sodium ethylate, 1280kg of dehydrated alcohol to the reactor of clean, dry 2000L;

[0037] (2) Control the temperature between 60°C and 65°C, add 97kg of trichloropicrin dropwise, continue the heat preservation reaction for 3 hours after the addition, and recover 900kg of absolute ethanol by atmospheric distillation;

[0038] (3) Add 1600kg of water, dissolve all the residue, add 1280kg of n-hexane to extract;

[0039] (4) The organic phase enters the rectifying tower, adds sodium ethylate, sodium tert-butoxide 0.05kg, and the normal pressure control reflux ratio is 1~2, first normal pressure steams 1024kg of n-heptane;

[0040] (5) control the reflux ratio again to be 3~5, rectify product tetraethyl orthocarbonate under the pressure of-0.098MPa, obtain product altogether: 103kg, purity 99.7%, single impurity<0.1%, yield 91%.

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Abstract

The invention relates to the field of refining chemicals and specifically relates to a method for efficiently rectifying and producing tetraethyl orthocarbonate. According to the method, a low-polarity inert solvent is used for treating tetraethyl orthocarbonate, so that the extracting function is achieved, less water can be co-boiled and brought away in a rectifying process and the product is prevented from degrading in the rectifying process; the solid alkali is added, so that the pH value of the rectifying system is increased and the product is prevented from continuously degrading under the effect of pH value decreasing in the rectifying process; the technical measure is adopted for acquiring the efficiently rectified and stably produced high-purity tetraethyl orthocarbonate. Comparedwith the present technology, the method provided by the invention has the characteristics of high efficiency, stability, and the like, the high-purity product can be continuously rectified and separated and the purity of the product can reach up to 99.5% or above.

Description

technical field [0001] The invention relates to the field of fine chemicals, in particular to a method for producing tetraethyl orthocarbonate through efficient distillation. Background technique [0002] Tetraethyl orthocarbonate is an intermediate of the antihypertensive drug candesartan, CAS: 6280-87-1, its appearance is a colorless transparent liquid, its molecular weight is 192.25, and its structural formula is: (C 2 h 5 O) 4 c. [0003] U.S. Patent 2002 / 0061984 reported a method for preparing tetraethyl orthocarbonate by reacting trichloroacetonitrile and sodium ethylate in absolute ethanol. In this patent, the sodium cyanide produced by the reaction is oxidized in the aqueous phase using strong oxidant hydrogen peroxide, sodium hypochlorite, etc. This method has following shortcoming in industrial-scale production: (1) use strong oxidizing agent such as hydrogen peroxide, the cyanide in sodium hypochlorite treatment water is a violent exothermic reaction, and with...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C07C41/60C07C43/32
Inventor 王玉琴詹玉进
Owner GENCHEM & GENPHARM CHANGZHOU CO LTD