Overview[1]
The traditional synthesis method of o-methylanisole (OM) is to react with o-methylphenol (OC) and methyl chloride or dimethyl sulfate (DMS). Since methyl chloride and DMS are toxic and the products contain acids that corrode equipment, their applications are limited. In addition, methanol can also be used as a methylating reagent to synthesize OM, but it has not been popularized due to the unsatisfactory activity of methanol. Dimethyl carbonate (DMC) is an emerging green chemical in recent years. Because its molecule contains reactive groups such as methyl, methoxy and carbonyl, it is used as a traditional chemical in organic synthesis such as DMS, methyl chloride and phosgene. It has been widely used as a substitute for reagents.
Apply[1]
O-methyl anisole (OM) is an important pharmaceutical and pesticide intermediate, and an important raw material for the synthesis of pressure-sensitive and heat-sensitive dyes. It is used in oil antioxidants, plastic processing stabilizers, and edible spices. Wide range of applications.
Preparation[2]
O-methyl anisole is prepared as follows:
1) The preparation process of the catalyst is as follows: Mix 120 grams of HZSM-5 molecular sieve with a molar silicon to aluminum ratio of 20, 60 grams of diatomite, and 100 grams of silica sol containing 20% silica by weight, and add An appropriate amount of 10% dilute nitric acid is used as an extrusion aid for extrusion molding. Dry at 120℃ and bake at 500℃ for 10 hours. Cut the above catalyst into 1-3 mm to prepare columnar catalyst precursor A0. Add 20 grams of parent catalyst A0 to 50 ml of 10% nitric acid aqueous solution by weight, and soak at 30°C for 4 hours. Dry at 120℃ and roast at 550℃ for 10 hours to prepare A1. 20 grams of A1 were steam treated in a 100% water vapor atmosphere for 10 hours, the treatment temperature was 550°C, and roasted at 550°C for 3 hours to prepare A2. A 20g A2 sample was impregnated with a calcium nitrate aqueous solution with a concentration of 0.18% by weight. Drying at 120°C for 24 hours, and roasting at 600°C for 3 hours, the weight percentage of calcium oxide in the catalyst was 0.1%, and Catalyst A was obtained, in which the molecular sieve content was 60%.
2) Use o-cresol and methanol as raw materials to produce o-methyl anisole through etherification reaction: use the prepared catalyst to perform o-cresol methanol etherification reaction in a fixed bed reactor. The raw materials o-cresol, methanol and water vapor are preheated and enter the reactor for reaction, and the reaction products are analyzed by online chromatography. The gas chromatograph is Agilent 7890A, and the chromatographic column is a cyclodextrin column 30mX0.25mmX0.25μm. Chromatographic analysis conditions: Column temperature: initial temperature 150°C, dwell for 15 minutes, heating rate 10°C/min to 180°C, constant temperature for 5.3 minutes; carrier gas is high-purity nitrogen, pre-column pressure: 6.5 pisa, column flow rate 12.6cm/ sec. The loading amount of the reaction catalyst is 20.0 grams, the weight space velocity is 0.5-20 hours, the reaction temperature is 250-500°C, the diluting gas is water vapor, and the molar ratio of diluting gas and o-cresol is 0.5-20. The molar ratio of the raw materials o-cresol and methanol The molar ratio is 1:10 to 1:3.
Main reference materials
[1] KOAc/NaY catalyzed synthesis of o-methyl anisole
[2] CN201710595153.9 Preparation method of etherification catalyst and method of producing o-methyl anisole
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