Method for preparing phenolic resin by adopting pyrrole acidic ionic liquid as catalyst

[0020] Example 1

[0021] Add 0.1 mol of N-methylpyrrolidone to a 250ml four-necked flask with a mechanical stirring device. Use a constant pressure funnel to slowly add 98% sulfuric acid in the same amount under ice bath. Control the rate at 10s/drop to prevent The reaction was too violent; after the addition, it was stirred in a 60°C water bath for 24 hours. The obtained liquid was washed three times with ethyl acetate, rotary evaporated and dried in vacuum to obtain a pale yellow viscous ionic liquid (1) N-methylpyrrolidone hydrogen sulfate ([Hnmp]HSO 4 ).

[0022] Add phenol (P) and formaldehyde (F) in a molar ratio of 1:0.75 to a 1000ml three-necked flask equipped with a reflux tube and a stirrer. Use pyrrole-based acidic ionic liquid as a catalyst and add 0.2wt% ionic liquid (1) Heat to reflux state while stirring, keep this state for 2h, then add 8wt% polyvinyl alcohol (PVA) aqueous solution, keep reflux state and continue to stir and disperse for 40min, finally add 10wt% curing agent hexamethylenetetramine (HMTA), After about half an hour, if yellow spherical particles appear in the flask, the heating can be stopped. The phenolic resin pellets are separated while it is hot. The filtrate is cooled to below 10°C. The pyrrole acid ionic liquid and water are automatically phase-separated to separate the pyrrole acid ionic liquid. Reuse. The product is poured out, filtered, washed with water, and dried to obtain phenolic resin balls. The weight of the phenolic resin microspheres was weighed to 62.25g, the diameter of the spheres below 0.8mm accounted for 9.6%, the diameter of 0.8-1.0mm accounted for 70.8%, and the above 1.0mm accounted for 19.6%, and the total yield was 70%.

[0023] Example 2

[0024] Add 0.1 mol of N-methylpyrrolidone to a 250ml four-necked flask with a mechanical stirring device. Use a constant pressure funnel to slowly add 80% phosphoric acid in an amount of other substances under ice bath, and control the rate at 10s/drop to prevent The reaction was too violent; after the addition, it was stirred in a 60°C water bath for 24 hours. The obtained liquid was washed three times with ethyl acetate, rotary evaporated and dried in vacuum to obtain a pale yellow viscous ionic liquid (2) N-methylpyrrolidone hydrogen sulfate ([Hnmp]HSO 4 ).

[0025] A 1000ml three-necked flask equipped with a reflux tube and a stirrer was added with a molar ratio of 1:0.9 resorcinol (P) and formaldehyde (F), using pyrrole acidic ionic liquid as a catalyst, adding 0.3wt% ionic liquid ( 2) While stirring, heat to reflux state, keep this state for 0.5h, then add 8wt% polyvinyl alcohol (PVA) aqueous solution, keep reflux state and continue to stir and disperse for 40min, finally add 10wt% curing agent hexamethylenetetramine ( HMTA). After about half an hour, if yellow spherical particles appear in the flask, stop heating, and separate the phenolic resin pellets while it is hot. The filtrate is cooled to below 10°C, and the pyrrole acid ionic liquid and water are automatically phase-separated to separate the pyrrole. Acidic ionic liquid is reused. The product is poured out, filtered, washed with water, and dried to obtain phenolic resin balls. The weight of the phenolic resin microspheres was weighed to 69.56g, the diameter of the spheres below 0.8mm accounted for 3.4%, the diameter of 0.8-1.0mm accounted for 82.3%, and the above 1.0mm accounted for 16.1%, the total yield was 93.5%.

[0026] figure 1 It is an electron micrograph of the synthesized phenolic resin beads. From the figure, it can be seen that the phenolic resin beads between 0.8mm and 1.0mm have good sphericity and smooth surface.

[0027] Example 3

[0028] Add 0.1 mol of N-methylpyrrolidone to a 250ml four-necked flask with a mechanical stirring device. Use a constant pressure funnel to slowly add an equivalent amount of p-toluenesulfonic acid aqueous solution under ice bath, and control the rate at 10s/drop. To prevent the reaction from being too violent; after the addition is complete, stir in a 60°C water bath for 24 hours. The obtained liquid was washed three times with ethyl acetate, rotary evaporated and dried in vacuum to obtain a light yellow viscous ionic liquid (3) N-methylpyrrolidone hydrogen sulfate ([Hnmp]HSO 4 ).

[0029] Add p-methylphenol (P) and formaldehyde (F) in a molar ratio of 1:0.8 to a 1000ml three-necked flask equipped with a reflux tube and a stirrer. Use pyrrole acid ionic liquid as a catalyst and add 0.5wt% ionic liquid. (3) Heat to reflux state while stirring, keep this state for 1.0h, then add 8wt% polyvinyl alcohol (PVA) aqueous solution, keep refluxing state and continue to stir and disperse for 40min, finally add 10wt% curing agent hexamethylenetetramine (HMTA), after about half an hour, if yellow spherical particles appear in the flask, stop heating, separate the phenolic resin pellets while it is hot, and cool the filtrate to below 10°C. The pyrrole-based acidic ionic liquid and water are automatically phase-separated to separate the pyrrole Reuse of acid-like ionic liquids. The product is poured out, filtered, washed with water, and dried to obtain phenolic resin balls. The weight of the phenolic resin microspheres was weighed to 65.32g, the diameter of the spheres below 0.8mm accounted for 7.7%, the diameter of 0.8-1.0mm accounted for 76%, and the above 1.0mm accounted for 16.3%, and the total yield was 85%.