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The preparation method of malonate

A technology of malonate and malonate, applied in the field of malonate preparation, which can solve the problems of incomplete esterification, high requirements for stirring equipment, and poor dispersion

Inactive Publication Date: 2011-12-07
重庆兰科化工有限责任公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0009] However, the method disclosed in the above-mentioned documents has the following defects: 1, cyanoacetic acid is hydrolyzed under sulfuric acid conditions, which easily generates amides, resulting in low hydrolysis conversion rate; 2, cyanoacetic acid is hydrolyzed under hydrochloric acid conditions, and the hydrolysis conversion rate is high, but The way of washing and desalting with alcohol will increase the consumption of alcohol and significantly prolong the esterification time with water, which is not conducive to large-scale industrial production
3. Due to the hydrolysis reaction of malonic acid in water when the temperature reaches 70°C, the extraction and esterification method is used, the esterification reaction is not complete, and the decomposition of malonic acid results in a decrease in the yield of malonate
4. The anhydrous sodium malonate mixed salt prepared by alkaline hydrolysis process is used for esterification reaction, which is easy to form viscous paste, poor dispersibility, high requirements for mixing equipment, and certain difficulty in implementation in production

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0032] Weigh 95g (1.0mol) of chloroacetic acid and dissolve it in 48g of water, adjust the pH to 6.5-7.5 with 216g of 25% saturated sodium carbonate solution at 20°C to form a sodium chloroacetate solution. Add this solution to 196g of 30% sodium cyanide solution, raise the temperature to 50°C to trigger the cyanation reaction, stop heating when the temperature reaches 85-90°C, let it react naturally to the highest temperature and then cool down rapidly, and react at 93°C for 0.5 ~1h to stop the reaction. After the reaction solution drops to a certain temperature, add 150g of 40% liquid caustic soda, react at 105-110°C under a slight negative pressure for 4-5 hours, cool to room temperature, neutralize the solution with 45g of concentrated hydrochloric acid to PH=8, and the feed liquid settles for 1 ~2h, filter to remove 4g of organic flocs. The filtrate was concentrated under vacuum at 100°C to obtain 550g of water, then 295.9g of concentrated hydrochloric acid was added to ...

Embodiment 2

[0035]Dissolve 95g (1.0mol) of chloroacetic acid in 48g of water, and adjust the pH to 6.5-7.5 with 216g of 25% saturated sodium carbonate solution at 20°C to form a sodium chloroacetate solution.

[0036] Take by weighing the liquid sodium cyanide 219.2g (26.82% of sodium cyanide content, 6.85% of sodium carbonate content, 1.65% of sodium hydroxide content) of the liquid sodium cyanide prepared by Angle method hydrogen cyanide synthesis gas and sodium hydroxide reaction, according to the The residual alkali (sodium carbonate and sodium hydroxide) analysis data is calculated as the residual alkali amount is 0.1%, and the amount of anhydrous calcium chloride is added. Sodium cyanide and calcium chloride were reacted for 0.5h at 30°C, and the residual alkali in sodium cyanide was analyzed to be less than 0.5%.

[0037] Add sodium chloroacetate solution to the treated sodium cyanide suspension, raise the temperature to 50°C to initiate the cyanation reaction, stop heating when th...

Embodiment 3

[0039] Replace methanol with 138g of ethanol, all the other are the same as in Example 2, finally obtain 143.2g of product, the content of diethyl malonate is 99.1% through gas chromatography analysis, and the yield is 89.5%.

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Abstract

The invention discloses a preparation method of malonate, which uses chloroacetic acid as a raw material to carry out neutralization reaction, cyanation reaction, alkali hydrolysis reaction, dehydration, acidification reaction, re-dehydration and esterification reaction, and is characterized in that: acidification reaction, further Dehydration and esterification reaction process. The acidification reaction refers to the reaction of sodium malonate and acid in the alkali hydrolysis reaction solution to generate malonate and sodium salt, after the reaction is completed, the undissolved inorganic salt is filtered and separated, and the filtrate is vacuum concentrated and dehydrated to obtain a malonate mixed salt; Esterification refers to the esterification of malonic acid mixed salt with alcohol, water-carrying agent and sulfuric acid to prepare malonate. The preparation method of malonate provided by the invention can make the conversion rate of esterification reaction up to more than 92%, and the product yield can reach more than 85%. The reaction conditions are mild, the process flow is short, the operation is simple, safe, environmentally friendly, easy to implement, and low Low, easy to industrial production, has high application value.

Description

technical field [0001] The invention relates to a preparation method of malonate. Background technique [0002] Malonate is mainly used in organic synthesis, and is an important intermediate in the synthesis of pesticides, medicines, and fine chemical products. The traditional synthetic process route is to use chloroacetic acid as raw material to prepare through neutralization, cyanation, hydrolysis and esterification and other processes. Among them, hydrolysis is divided into two processes: alkali hydrolysis and acid hydrolysis, and the acid used is sulfuric acid or hydrochloric acid; esterification is divided into extraction esterification and esterification with water. [0003] JP 51-143612 A, JP 59-007135, JP 59-007136 A, US 2337858 disclose the preparation of malonic acid or its esters by hydrolysis of cyanoacetic acid or its salt such as sodium salt in the presence of sulfuric acid. [0004] "Organic Syntheses Collective" [Organic Syntheses Collective]-Volume II (A.H...

Claims

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Application Information

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IPC IPC(8): C07C69/38C07C67/08
Inventor 陈世勇唐翔袁福仙魏娜陈林蒋昌珍吴尘
Owner 重庆兰科化工有限责任公司
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