Preparation method of environment-friendly type alpha-cyanoacrylate
A technology of cyanoacrylate and cyanoacetate is applied in the field of preparation of α-cyanoacrylate, can solve the problems of environmental pollution, can not meet, can not meet environmental protection requirements, etc., and achieves the effect of high yield
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Embodiment 1
[0034] Applied to the preparation of ethyl α-cyanoacrylate
[0035] Add ethyl cyanoacetate and toluene into a 1000ml three-necked flask, and when the temperature rises to 60°C, add a mixture of hexahydropyridine and formaldehyde solution. After the dropwise addition, heat and keep warm, and keep reflux at 60°C for 1 hour. Then carry out azeotropic dehydration for 2 hours, then add tributyl citrate, phosphorus pentoxide, p-hydroxyanisole, etc., and crack at a temperature of 170°C and a vacuum of 1 mmHg to obtain the crude monomer of ethyl α-cyanoacrylate , after rectification, the refined monomer of α-ethyl cyanoacrylate with a purity of 99.9% can be obtained, and the calculated yield is 80%.
[0036] Wherein, the feeding molar ratio of ethyl cyanoacetate and formaldehyde aqueous solution is 1.00:1, and the input amount of toluene is 100ml / mol formaldehyde, and the input amount of hexahydropyridine is 0.2ml / mol formaldehyde, and the input amount of tributyl citrate is 5g / mol. ...
Embodiment 2
[0039] Applied to the preparation of methoxyethyl α-cyanoacrylate
[0040] Add paraformaldehyde and dichloropropane into a 1000ml three-necked flask. When the temperature rises to 60°C, add a mixture of sodium hydroxide and methoxyethyl cyanoacetate. After the dropwise addition, heat and keep it warm. Keep reflux at -90°C for 1.5h, carry out azeotropic dehydration for 3h, then add synthetic vegetable esters, phosphorus pentoxide, 2,5-di-tert-butylhydroquinone, etc., and crack at 200°C and 10mmHg vacuum , to obtain the crude monomer of methoxyethyl α-cyanoacrylate, after rectification, the refined monomer of α-ethyl cyanoacrylate with a purity of 99.9% can be obtained, and the calculated yield is 75%.
[0041] Wherein, the molar ratio of methoxyethyl cyanoacetate and paraformaldehyde is 1.04:1, the input amount of dichloropropane is 200ml / mol paraformaldehyde, and the input amount of sodium hydroxide is 0.6ml / mol paraformaldehyde, The input amount of synthetic vegetable ester ...
Embodiment 3
[0043] Applied to the preparation of n-butyl α-cyanoacrylate
[0044]Add formaldehyde aqueous solution and dimethyl carbonate into a 1000ml three-necked flask. When the temperature rises to 65°C, add the mixture of potassium hydroxide and n-butyl cyanoacetate. After the dropwise addition, heat and keep warm. Keep reflux for 3 hours, carry out azeotropic dehydration for 3.5 hours, then add epoxidized soybean oil, phosphorus pentoxide, butyl hydroxyanisole, etc., and crack at 190°C and 5mmHg vacuum to obtain n-butyl α-cyanoacrylate The crude monomer, after rectification, can obtain the refined monomer of α-n-butyl cyanoacrylate with a purity of 99.9%, and the yield is 70%.
[0045] Wherein, the molar ratio of n-butyl cyanoacetate and formaldehyde aqueous solution is 1.02:1, the input amount of dimethyl carbonate is 100ml / mol formaldehyde, the input amount of potassium hydroxide is 0.4ml / mol formaldehyde, the input amount of epoxy soybean oil Formaldehyde is 15g / mol, the input a...
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