Preparation method of exo-norbornene dianhydride
A bornane dioic anhydride and exterior technology are applied in the field of preparation of exterior norbornene dioic anhydride, can solve the problems of pollutants, low efficiency, low purity and the like, and achieve the effects of high purity, reduced production cost and high yield
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Embodiment 1
[0034] Preparation of endo-norbornene diacid anhydride
[0035] In a 1L three-necked flask, add maleic anhydride (150.0g, 1.5mol) and 450mL of methyl tert-butyl ether, cool to 10°C, stir slowly and dropwise add freshly depolymerized cyclopentadiene diluted with 260mL of methyl tert-butyl ether Ethylene monomer (131.5 g, 2.0 mol) (pre-frozen, since cyclopentadiene readily polymerizes at room temperature). Control the temperature below 20°C and react for 2 hours. After the reaction, a large amount of white solids precipitated out, filtered with suction, washed with methyl tert-butyl ether (50mL×3), dried the white solids in a vacuum oven at 40°C for 12 hours, and obtained a white crystal product (234.9 g, 93.5%). The melting point is 154.3-158.0°C. 1 H NMR (400MHz, CDCl 3 )δ: 6.31(t, J=1.8Hz, 2H), 3.58(q, J=1.6Hz, 2H), 3.52-3.50(m, 2H), 1.79(dt, J=9.2, 2.0Hz, 1H), 1.58-1.56 (m, 1H); 13 C NMR (100MHz, CDCl 3 )δ: 171.3, 135.4, 52.7, 47.0, 46.0.
Embodiment 2
[0037] Preparation of exo-norbornene diacid anhydride
[0038] Under the protection of nitrogen, add endo-norbornene diacid anhydride (10.0g, 60.9mmol) and 15mL of phthalic dimethyl ether into a 100mL three-necked flask, heat to 180°C and stir for 1h, cool to room temperature in an ice-water bath and cool to 10°C with solid Precipitated and filtered to obtain 3.0 g of white solid (exo: endo = 30.2: 1); added endo-norbornene dioic anhydride (10.0 g, 60.9 mmol) to the filtrate and continued heating at 180 ° C for 1 h, cooled to room temperature in an ice-water bath to 10 A solid precipitated at ℃, and 6.5 g of a white solid was obtained by filtration (exo: endo = 7.2: 1); then, endo-norbornene dioic anhydride (10.0 g, 60.9 mmol) was added to the filtrate and continued heating at 180 °C for 1 h, and cooled to room temperature. Cool the temperature in the water bath to 10°C, solids precipitated, and filtered to obtain 11.5 g of white solids (exo:endo=2.7:1); then added endo-norbor...
Embodiment 3
[0040]Under the protection of nitrogen, add endo-norbornene diacid anhydride (10.0g, 60.9mmol) and 15mL of phthalic dimethyl ether into a 100mL three-necked flask, heat to 200°C and stir for 1h, cool to room temperature in an ice-water bath and cool to 10°C with solid Precipitated and filtered to obtain 3.1 g of white solid (exo: endo = 32.3: 1); added endo-norbornene dianhydride (10.0 g, 60.9 mmol) to the filtrate and continued heating at 200 ° C for 1 h, cooled to room temperature in an ice-water bath to 10 A solid precipitated at ℃, filtered to obtain 6.9 g of white solid (exo: endo = 7.6: 1); then added endo-norbornene dioic anhydride (10.0 g, 60.9 mmol) to the filtrate and continued heating at 200 ° C for 1 h, cooled to room temperature and ice Cool the temperature in the water bath to 10°C, solids precipitated, and filtered to obtain 12.7 g of white solids (exo:endo=3.0:1); then added endo-norbornene dioic anhydride (10.0 g, 60.9 mmol) to the filtrate and continued heatin...
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