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Method for producing 2-cyanoacrylate

A technology of cyanoacrylate and cyanoacetate, which is applied in the field of 2-cyanoacrylate production, can solve the problems of difficult production control, shortened reaction time, increased production cost, etc., so as to avoid catalyst deactivation, Strong operability and waste reduction effect

Active Publication Date: 2012-07-18
潍坊滨海石油化工有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

This method requires a large investment in equipment, and the required raw materials have no industrial products, and by-products are easily produced, and the production control is difficult.
[0006] Patent CN1046707C discloses a method for obtaining 2-cyanoacrylate by reacting cyanoacetate and benzophenone in a polar organic solvent. , piperidine and β-alanine and its acetate as catalysts, AlCl can also be added 3 , ZrCl 4 or ZnCl 2 Waiting for Lewis acid to shorten the reaction time, the post-reaction treatment process of this process is complicated, and the yield is also low
[0007] In the patent CN101492394A, an acid anhydride dehydrating agent is added during the reaction of benzophenone, isooctyl cyanoacetate, catalyst and solvent, and it is expected to increase the conversion rate of isooctyl cyanoacetate, so that the reaction becomes an irreversible process, but the actual situation is the initial stage The reaction speed is fast, adding a dehydrating agent does not significantly change the reaction speed, but greatly increases the production cost. At the same time, the product operation after washing reaction in industrial production produces a large amount of low-concentration acid-containing wastewater
[0008] Patent US5451694 discloses that under the conditions of ammonium ions, no organic solvent and a certain vacuum, propionic acid is a water-carrying agent and a catalyst, and the reaction time of cyanoacetate and carbonylation compound is shortened to 5 hours, while achieving better Yield, but the process steams a large amount of propionic acid and water, and the follow-up treatment cost is higher in industrial production
[0009] Patent CN101589020A discloses a method of using propionic acid and ammonium acetate as a catalyst, utilizing cyanoacetate, carbonyl compound and solvent to reflux reaction under vacuum, wherein the content of by-product amides in the reaction product is less than 0.5wt%; in this method The molar ratio of the ammonium catalyst to the carbonyl compound is in the range of 0.6-1.5. Since more ammonium catalysts are used, they will be decomposed with water to form ammonia and acetic acid after being heated for a long time in the reactor, or dehydrated and deactivated to form amides. Add a large amount of The catalyzer also brought considerable trouble to the follow-up product refining treatment, and the separation of distilling propionic acid, water and acetic acid is also difficult to handle in industry, and the economic benefit of this process is low

Method used

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  • Method for producing 2-cyanoacrylate
  • Method for producing 2-cyanoacrylate

Examples

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Effect test

Embodiment 1

[0032] In a four-necked flask with stirring and a thermometer, put 198g (1mol) of 2-ethylhexyl cyanoacetate, 546.66g (3mol) of benzophenone, and 161.1g of catalyst solution (comprising 80.55g of acetic acid, 38.54g of ammonium acetate and 42.01g sodium bicarbonate), 200g heptane, install the water separator and condenser, gradually raise the reaction temperature to reflux at 105°C, add 10g catalyst solution every 1h, and simultaneously separate the lower aqueous solution of the condensate, heptane Flow back into the four-necked flask. Sampling is performed to detect that the content of 2-ethylhexyl cyanoacetate is less than 3 wt%, and the reaction is terminated, and the content of amide impurities is less than 0.4 wt%. Heptane was distilled off under normal pressure, acetic acid was distilled off under reduced pressure until the content of acetic acid was less than 0.5wt% as the end point, 20wt% ammonium bicarbonate was added to neutralize to pH=7, and the upper oil phase was ...

Embodiment 2

[0034] In a four-necked flask with stirring and a thermometer, drop 396g (2mol) cyanoacetate-2-ethylhexyl, 728.88g (4mol) benzophenone, 530.16g catalyst solution (463.89g acetic acid, 30.83g ammonium acetate, 35.44g of acetamide), 200g of butyl acetate, install a water separator and a condenser, gradually raise the reaction temperature to reflux at 110°C, add 20g of catalyst solution every 1h, and simultaneously separate the lower aqueous solution of the condensate, and the heptane flow Return to the four-necked flask. Sampling is performed to detect that the content of 2-ethylhexyl cyanoacetate is less than 2%, the reaction is terminated, and the content of amide impurities is less than 0.5 wt%. Distill butyl acetate under normal pressure, distill acetic acid under reduced pressure until the content of acetic acid is less than 0.5wt% as the end point, add 25wt% sodium carbonate to neutralize to pH = 7, and separate the upper oil phase. The oily phase was distilled under reduce...

Embodiment 3

[0036] Utilize cyanoacetic acid and isooctyl alcohol to obtain -2-ethylhexyl cyanoacetate under the catalysis of sulfuric acid, in the four-necked flask with stirring, thermometer, drop 594g (3mol) -2-ethylhexyl cyanoacetate, 546.66 g (3mol) benzophenone, 386.72g catalyst solution (comprising 290.04g acetic acid, 25.22g cyanoacetamide and 71.46g malonamide), 200g dimethyl carbonate, install water trap, condenser, the reaction temperature Gradually raise to reflux at 80°C, add 10g of catalyst solution every 1h, and at the same time separate the lower aqueous solution of the condensate, and return the heptane to the four-necked flask. Sampling is performed to detect that the content of 2-ethylhexyl cyanoacetate is less than 3 wt%, and the reaction is terminated, and the content of amide impurities is less than 0.4 wt%. Dimethyl carbonate was distilled off under normal pressure, acetic acid was distilled off under reduced pressure until the content of acetic acid was less than 0....

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Abstract

The invention discloses a method for producing 2-cyanoacrylate. The method comprises the following steps of: (1) undergoing an azeotropic reflux reaction on cyanoacetate, a carbonyl compound, a catalyst solution and an organic solvent at the temperature of 80-140 DEG C, continuously replenishing the catalyst solution in a reacting process, removing a lower layer acid-containing aqueous solution of an azeotropic mixture condensate, and stopping reacting till the content of cyanoacetate is lower than 3-10 percent by weight; (2) distilling a product obtained in the step (1) under the normal pressure, evaporating the solvent out, evaporating acetic acid out under reduced pressure, neutralizing a distilled mixture till the pH is 7-8, and separating an upper layer oil phase and a lower layer water phase out; and (3) distilling the upper layer oil phase under reduced pressure, and collecting a fraction under the condition that the temperature is 100-190 DEG C and the pressure is 0.5-10mmHg to obtain a 2-cyanoacrylate product. The invention provides an economical and practical method for producing 2-cyanoacrylate. Due to the adoption of the method, the product yield can be increased, and a high-purity product can be obtained.

Description

technical field [0001] The invention belongs to the field of fine chemical industry, in particular to a method for producing 2-cyanoacrylate with cyanoacetate and carbonyl compound as raw materials. Background technique [0002] 2-Cyanoacrylates, especially 2-cyano-3,3-diarylacrylates, are mainly used as high-efficiency UV absorbers in plastics, inks, paints and cosmetics. The representative industrial products mainly include: octocrylene, 2-cyano-3,3-diphenylacrylate-2-ethylhexyl (such as Ciba parsol 340 and basf UV3039); etocrylene, 2-cyano Ethyl-3,3-diphenylacrylate (such as basf UV 3035). [0003] In the prior art, 2-cyanoacrylate can be obtained by knoevenagel condensation reaction of cyanoacetate and a suitable carbonyl compound under weakly basic catalyst conditions, azeotropic dehydration in a solvent (see US3215724, EP1430023 and DE14314035). The reaction needs to be carried out at a temperature of 80-140° C., but the reaction rate is slow, so the reaction require...

Claims

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Application Information

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IPC IPC(8): C07C253/30C07C255/41C07C255/31
Inventor 窦荣坦郭希田
Owner 潍坊滨海石油化工有限公司
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