- Apr 23, 2018 -
1. Acetic anhydride method: will be tert-butyl alcohol, acetic anhydride and anhydrous zinc chloride blending heating reflux 2h, and then cooling, distillation to temperature of 110 ℃, the coarse distillate with washing, and 10% potassium carbonate to wash to neutral, with anhydrous potassium carbonate drying, and then by distillation, collect 95-96 ℃ fractions of the finished product. 2. Acetyl chloride method: will tert-butyl alcohol, n,n-dimethyl aniline and anhydrous ether mixture, heating reflux, and then adding acetyl chloride, control feeding temperature, maintain moderate reflux rate, add 2/3 acetyl chloride, n,n-two methyl aniline hydrochloride crystallization, ice bath cooling, then heating 1h.
Add water so that all solids dissolved, separation of ether layer, with cold 10% sulfuric acid extraction, with saturated sodium bicarbonate solution washed 1 times, dry with anhydrous sodium sulfate, fractionation and finished.
3. Acetyl chloride-Magnesium method: Mix magnesium powder, butyl alcohol and anhydrous ether, add acetyl chloride and anhydrous ether solution, add cooling, add cold potassium carbonate aqueous solution, make it decompose, 3 times with ether extraction, dry with calcium chloride, distillation and finished.
4. System Law: In a reaction bottle equipped with a blender, drip funnel, and reflux condenser, add dry tert-Butyl alcohol (2) 57g (0.77mol), n,n-two methyl aniline 101g (106ml,0.84mol), anhydrous ether 100mL. Stir and heat until backflow. The drop of acetyl chloride 63g (0.80mol), the drop acceleration control in the removal of the heat source is still maintained reflux state. When about 2/3 of the acetyl chloride is added, the ammonium salt precipitates and reacts violently, which can be cooled by an ice water bath. Then slowly add the rest of the acetyl chloride. After the addition, continue to reflux reaction 1h. When cold to room temperature, add 100mL water and stir fully to dissolve the solid. Separate the organic layer. The organic layer was washed with 10% sulfuric acid and then washed with a saturated sodium bicarbonate solution, and anhydrous sodium sulfate was dried. Steam out ethyl ether, fractionation, collect 96~98℃ fractions, get acetic acid tert-butyl ester (1) 54g, yield 61%.