Method 1: Usage tetrabutylammonium bromide as a phase transfer driver to catalyze the response of p-cresol and dimethyl sulfate to synthesize p-methylanisole. The results reveal that when the molar proportion of dimethyl sulfate and also p-cresol is 1.4, the amount of stage transfer stimulant is 6%, pH= 8, the water bathroom temperature level is controlled at 50-60 ° C, and the reaction time is 6h, the greatest return of 4-Methylanisole can reach 92.36%.
Include 10.5 mL (0.1 mol) of p-cresol as well as 30mL of toluene into a three-necked flask furnished with a magnet, thermostat, dropping funnel, and also spherical reflux condenser, mix magnetically as well as warmth to 50 ° C in a water bath at the same time, include phase Transfer catalyst tetrabutylammonium bromide 1.93 g (0.006 mol), use a specific amount of 30% K2CO3 service to change the pH to be alkaline, regulate the temperature at 50-60 ° C, continue mixing for 40min, and also slowly drop (CH3) 2SO4 into the response container The solution was 13.23 mL (0.14 mol), and the going down time was 50min. At the same time, the pH of the remedy was regulated to be 8. After the dropping, the response was refluxed at the very same temperature for 6h. After the response was finished, the top organic layer was washed with 3 × 20mL10% ammonia water, as well as the liquid layer was gotten rid of by separation. Laundry with saturated NaCl service until neutral, and also completely dry with anhydrous CaCl2, filter, and also boil down under reduced pressure to gather the product. The item yield is 92.36%.
Technique 2: a prep work method of 4-Methylanisole, especially comprising the adhering to actions:
1) Neutralization response: p-cresol: 100.0 g (web content: 99.1%, 0.9176 mol), absolute ethanol: 600ml, open nitrogen defense, set nitrogen flow: 0.5 l/min. The external wall of the four-necked flask is cooled with cooling water, as well as the inner temperature is regulated not to go beyond 35 ° C. Gradually include sodium hydroxide: 37.5 g (0.9375 mol) right into the four-necked flask from the thermometer mouth (take out the thermostat). After feeding, the response was stirred for 1.0 hr. After the response is finished, the outer wall of the four-neck flask is heated with 85-90 ° C hot water, as well as the ethanol is constantly distilled out under the defense of nitrogen. In the later stage of purification, the outflow speed of ethanol will lessen and smaller. When the discharge of ethanol is really tiny, vacuum recuperation is executed, and the vacuum level is regulated to be above -0.08 MPa to recoup the ethanol to dry skin. The residue in the four-necked flask is sodium p-cresol, quantity: 121.1 g, content: regarding 98.2%.
2) Methylation response 1: In a 500ml four-necked flask geared up with a thermometer, a stirring paddle as well as a reflux condenser, placed the prepared salt p-cresol: 50.0 g (web content: concerning 98.2%, 0.3777 mol), cyclohexane Alkane: 300ml. The external wall surface of the four-neck flask was maintained warm with 40 ° C warm water, began stirring, as well as adjusted the stirring rate to be greater than 500r/min. Weigh dimethyl sulfate: 50.0 g (content: 98.7%, 0.3917 mol) and also participate in the consistent pressure dropping funnel, after that drop the dimethyl sulfate in the consistent stress dropping channel to four The methylation response was accomplished in a flask. After the enhancement of dimethyl sulfate is complete, keep the temperature for 5.0 to 8.0 hours.
3) Post-processing: After warmth preservation, filter after cooling. The filter cake was washed with 100ml cyclohexane, as well as dried out to acquire salt methyl sulfate: 50.8 g, content: 97.3%. After the filtrate was cleaned with alkaline water, the solvent was recouped (the cleaned alkaline water was made use of once again). After recuperation of the solvent, p-methylanisole was acquired: 45.6 g, material: 98.1%, yield: 97.0%.
4) Methylation response 2: take into a 500ml three-neck flask geared up with a thermostat, a stirring paddle as well as a reflux condenser: 42.5 g of sodium p-cresol (web content: concerning 98.2%, 0.3210 mol), methyl tetrahydrofuran: 300ml, Dry sodium methyl sulfate: 50.8 g (content: 97.3%, 0.3689 mol). Stirring was begun, and also the outer wall of the three-neck flask was heated up with an electric heating mantle, and also the response was refluxed for 5.0 to 8.0 hours. After the reaction was completed, it was cooled down to room temperature.
5) Post-processing: After cooling down, filter, and the filter cake is made of salt sulfate for detailed application. The filtrate was moved to a 500ml three-necked flask to recover methyl tetrahydrofuran. After healing, 4-Methylanisole was acquired: 38.5 g, detected content: 97.2%, return: 95.5%.
