Method for preparing vanilline
A technology of vanillin and methyl phenol, which is applied in the field of compound preparation, can solve the problems of phenol-containing wastewater, serious environmental pollution, high production cost, etc., achieve high product yield, reduce production cost, and save equipment investment
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Embodiment 1
[0021] Add 2-bromo-4-methylphenol (hereinafter referred to as monobromophenol) 75g (0.4 mole) in the medium-pressure reactor (pressure-resistant 2.5MPa) of 1000ml, 28% industrial sodium methylate solution 155g (containing sodium methylate 0.8 mol), basic copper carbonate 2.3g (0.01 mol). After blowing in nitrogen to replace the air in the kettle, the reaction was carried out at 100° C. and a stirring speed of 500 rpm for 3 hours. Then vent the pressure after passing the cooling water to cool down, open the lid of the kettle and drop into the still 1g of cobalt acetate, 72g of solid caustic soda (1.8 moles), 340ml of anhydrous methanol, feed oxygen and at 100 ℃ and a stirring speed of 500 rpm The reaction was carried out for 8 hours. Cool down, lower the temperature, take out the solution, first filter out the solids, then distill off the methanol, then add hydrochloric acid to adjust the pH of the solution to 4-5. After the solution was cooled in water at 15°C for 2 hours, v...
Embodiment 2
[0023] Add 75g (0.4 moles) of monobromophenol, 125g (containing 0.65 moles of sodium methoxide) of 28% industrial sodium methoxide solution, and 2.3g (0.01 moles) of basic copper carbonate in a 1000ml medium-pressure reactor (2.5MPa pressure resistance). . After blowing in nitrogen to replace the air in the kettle, the reaction was carried out at 100° C. and a stirring speed of 500 rpm for 3 hours. Then the cooling water is cooled to 40°C, the pressure is released, the lid of the kettle is opened, and 1g of cobalt acetate is dropped into the kettle, 72g of solid caustic soda (1.8 moles), 300ml of anhydrous methanol, and oxygen is fed into the kettle at 100°C and 500 rpm. The reaction was carried out for 9 hours at a constant stirring speed. Cool down, lower the temperature, take out the solution, first filter out the solids, then distill off the methanol, then add hydrochloric acid to adjust the pH of the solution to 4-5. After the solution was cooled in water at 15°C for 2 ...
Embodiment 3
[0025] Add monobromophenol 75g (0.4 mole) in the medium-pressure reactor (2.5MPa of pressure resistance) of 1000ml, 18% industrial sodium ethylate solution 300g (containing sodium ethylate 0.8 mole), basic copper carbonate 2.3g (0.01 mole) . After blowing in nitrogen to replace the air in the kettle, the reaction was carried out at 100° C. and a stirring speed of 500 rpm for 3 hours. Then pass cooling water to cool down to 40°C, and then put 1g of cobalt acetate, 72g (1.8 moles) of solid caustic soda, 200ml of absolute ethanol into the kettle, and feed oxygen at 100°C for 8 hours. After cooling and cooling down, the solution was taken out. Ethanol was distilled off first, and then hydrochloric acid was added to adjust the pH of the solution to 4-5. The solution was cooled in cold water at 15°C for 2 hours, and then crystals were precipitated. After filtration, the crude ethyl vanillin is distilled under reduced pressure, recrystallized from ethanol aqueous solution, recryst...
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