Dimethoxybenzene and preparation method thereof
A technology of phthalate and catechol, applied in the field of phthalate and its preparation, can solve the problems of waste solids, large amount of waste water, long operation cycle, etc., and achieve the effect of high yield
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[0023] The present invention provides a kind of new preparation method of phthalate, the method comprises the following steps,
[0024] 1) In the presence of a catalyst, catechol is used as a raw material, and dimethyl carbonate is used as a methylating agent to carry out a methylation reaction to obtain phthalic dimethyl ether, wherein the catalyst is 1,8- Diazabicyclo[5.4.0]undec-7-ene;
[0025] 2) The reaction product obtained in step 1) is distilled to reclaim dimethyl carbonate, and then distilled under reduced pressure to obtain o-phthalylene dimethyl ether.
[0026] According to the present invention, the methylation reaction is carried out with specific raw materials and catalysts through the green and environmentally friendly methylation reagent dimethyl carbonate, and in the reaction, dimethyl carbonate is used as a methylation reagent and also as a solvent , after the reaction is completed, dimethyl carbonate can be recovered by distillation, the dimethyl carbonate...
Embodiment 1
[0044] 1) Add catechol 11g (100mmol), dimethyl carbonate 63g (700mmol), DBU 12.2g (80mmol) in a 100ml stainless steel autoclave, replace with nitrogen twice, heat to 160°C for reaction, wait for pressure When the meter rises to 4MPa, slowly open the vent valve (connected to the condenser in front), release the pressure to 2MPa, and cycle like this. After 8 hours, the reaction ends, cool down to room temperature, vent, and post-treatment.
[0045]2) The reaction solution obtained in step 1) is subjected to atmospheric distillation, and the distillation temperature is 150° C. to obtain 45 grams of the previous cut; after the atmospheric distillation, further vacuum distillation is carried out to obtain o-phthalylene dimethyl ether (purity is 99%, weight 13.7 grams, yield 98.5%), the temperature of vacuum distillation is 130 ℃, and the pressure of vacuum distillation is-0.098MPa, in addition, the residue in the kettle after vacuum distillation is catalyst, reuses to next batch of ...
Embodiment 2
[0052] 1) Add 11 grams (100 mmol) of catechol, 54 grams (600 mmol) of dimethyl carbonate, and 10.7 grams (70 mmol) of DBU into a 100 ml stainless steel autoclave, replace with nitrogen twice, heat to 180 ° C, and react 8 Hours, after the reaction is finished, cool down to room temperature for post-processing.
[0053] 2) The reaction solution obtained in step 1) is subjected to atmospheric distillation, and the distillation temperature is 150° C. to obtain 40 grams of the front fraction (the front fraction is rectified at a rectification temperature of 110° C., and the methanol extracted from the top of the tower is reused. Dimethyl carbonate is produced, and the remaining dimethyl carbonate in the still is reused to the next batch of reactions); after atmospheric distillation, vacuum distillation is then carried out to obtain phthalic dimethyl ether (purity is 99.1%, weight 13.7 grams, Yield 98.2%), the temperature of vacuum distillation is 130 ℃, the pressure of vacuum disti...
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