Method for preparing metacresol via alkaline hydrolysis of o-chlorotoluene
A technology of o-chlorotoluene and cresol, which is applied in the field of preparing m-cresol by alkaline hydrolysis of o-chlorotoluene, can solve the problems of low m-cresol content and multiple by-products, and achieve simple post-processing, low production cost, and environmental protection Effect
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Embodiment 1
[0028] In a 1L autoclave, 112g potassium hydroxide, 56g calcium oxide, 175mL (1.5mol) o-chlorotoluene, 300mL pyridine were added, the reaction temperature was 200°C, and the constant pressure 1.5MPa was reacted for 20h. Cool to room temperature, take out the reactant in the kettle and filter, collect the solid and filtrate separately, and recover the filtrate directly for the next batch reaction. The solid was dissolved in water, fully dissolved, filtered, washed with water, collected the aqueous solution, adjusted to pH 3 with 15% hydrochloric acid, extracted twice with 100 mL of toluene, dried and distilled to remove the solvent to obtain 62.0 g of crude product. Then 62.0g of the crude product was passed through 200 mesh silica gel, using petroleum ether 60-90 as the eluent, and subjected to silica gel column chromatography to obtain 37.8g of pure m-cresol product, with a yield of 35.0% (calculated as potassium hydroxide), a by-product 19.9g of o-cresol. See the proton nucl...
Embodiment 2
[0030] In a 1L autoclave, add 299.9 g of cesium hydroxide after dewatering, 56 g of calcium oxide, 175 mL (1.5 mol) of o-chlorotoluene, and 250 mL of pyridine. The reaction temperature is 120° C. and the constant pressure is 2.0 MPa for 24 hours. Cool to room temperature, take out the reactant in the kettle and filter, collect the solid and filtrate separately, and recover the filtrate directly for the next batch reaction. The solid was dissolved in water, fully dissolved, filtered, washed with water, and the aqueous solution was collected, adjusted to pH 5 with 5% hydrochloric acid, and extracted twice with 100 mL of toluene. After drying, the solvent was distilled off to obtain 46.3 g of crude product. Then 46.3g of the crude product was passed through 300 mesh silica gel, using petroleum ether 60-90 as the eluent, and subjected to silica gel column chromatography. After silica gel column chromatography, 28.8 g of pure m-cresol product was obtained, and the yield was 26.7% (wi...
Embodiment 3
[0032] In a 1 L autoclave, add 80 g of sodium hydroxide, 56 g of calcium oxide, 175 mL (1.5 mol) of o-chlorotoluene, and 250 mL of 4,4'-bipyridine. The reaction temperature is 220° C. and the constant pressure is 2.5 MPa for 18 hours. Cool to room temperature, take out the reactant in the kettle and filter, collect the solid and filtrate separately, and recover the filtrate directly for the next batch reaction. The solid was dissolved in water, fully dissolved, filtered, washed with water, collected the aqueous solution, adjusted to pH 4 with 10% hydrochloric acid, extracted twice with 100 mL of toluene, dried and distilled to remove the solvent to obtain 38.9 g of crude product. Then 38.9g crude product was passed through 150 mesh silica gel, using petroleum ether 60-90 as the eluent, and silica gel column chromatography was used to obtain 22.7g pure m-cresol product, with a yield of 21.0% (calculated as sodium hydroxide), a by-product 12.3 g of o-cresol.
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