Method 1: Use tetrabutylammonium bromide as a stage transfer catalyst to militarize the response of p-cresol and dimethyl sulfate to synthesize 4-Methylanisole. The outcomes show that when the molar proportion of dimethyl sulfate and p-cresol is 1.4, the phase transfer The return of p-methylanisole can reach up to 92.36% under the condition of 6% driver quantity, pH= 8, water bathroom temperature level control 50-60 ℃, as well as response time 6h.
Add 10.5 mL (0.1 mol) of p-cresol and also 30mL of toluene right into a three-necked flask equipped with a magnet, thermometer, dropping funnel, as well as spherical reflux condenser, mix magnetically and warm to 50 ° C in a water bathroom at the same time, include stage Transfer catalyst tetrabutylammonium bromide 1.93 g (0.006 mol), utilize a particular amount of 30% K2CO3 service to readjust the pH to be alkaline, control the temperature level at 50-60 ° C, proceed mixing for 40min, and also slowly decrease (CH3) 2SO4 into the reaction bottle The remedy was 13.23 mL (0.14 mol), as well as the going down time was 50min. At the same time, the pH of the solution was regulated to be 8. After the dropping, the reaction was refluxed at the same temperature level for 6h. After the reaction was finished, the top natural layer was washed with 3 × 20mL10% ammonia water, as well as the aqueous layer was eliminated by splitting up. Clean with saturated NaCl solution till neutral, and dry with anhydrous CaCl2, filter, and boil down under reduced pressure to collect the product. The item yield is 92.36%.
Method 2: a preparation approach of 4-Methylanisole, specifically making up the adhering to steps:
1) Neutralization response: p-cresol: 100.0 g (material: 99.1%, 0.9176 mol), outright ethanol: 600ml, open nitrogen protection, established nitrogen flow: 0.5 l/min. The outer wall surface of the four-necked flask is cooled down with cooling water, and also the inner temperature level is regulated not to exceed 35 ° C. Slowly include salt hydroxide: 37.5 g (0.9375 mol) into the four-necked flask from the thermostat mouth (pull out the thermostat). After feeding, the reaction was mixed for 1.0 hour. After the response is completed, the outer wall surface of the four-neck flask is heated with 85-90 ° C warm water, and also the ethanol is constantly distilled out under the defense of nitrogen. In the later phase of purification, the discharge rate of ethanol will certainly become smaller as well as smaller. When the discharge of ethanol is really small, vacuum cleaner healing is executed, as well as the vacuum cleaner degree is managed to be above -0.08 MPa to recover the ethanol to dry skin. The residue in the four-necked flask is salt p-cresol, amount: 121.1 g, web content: about 98.2%.
2) Methylation reaction 1: In a 500ml four-necked flask outfitted with a thermometer, a mixing paddle as well as a reflux condenser, put the ready salt p-cresol: 50.0 g (material: regarding 98.2%, 0.3777 mol), cyclohexane Alkane: 300ml. The external wall surface of the four-neck flask was kept cozy with 40 ° C warm water, started stirring, and also changed the mixing speed to be more than 500r/min. Weigh dimethyl sulfate: 50.0 g (content: 98.7%, 0.3917 mol) and also participate in the constant stress going down funnel, then drop the dimethyl sulfate in the continuous stress dropping channel to four The methylation reaction was performed in a flask. After the enhancement of dimethyl sulfate is total, maintain the temperature for 5.0 to 8.0 hrs.
3) Post-processing: After warm conservation, filter after cooling down. The filter cake was cleaned with 100ml cyclohexane, and also dried out to acquire sodium methyl sulfate: 50.8 g, material: 97.3%. After the filtrate was cleaned with alkaline water, the solvent was recouped (the washed alkaline water was reused), as well as the solvent recuperation was finished to get 4-Methylanisole: 45.6 g, material: 98.1%, return: 97.0%.
4) Methylation response 2: put into a 500ml three-neck flask furnished with a thermometer, a stirring paddle as well as a reflux condenser: 42.5 g of sodium p-cresol (web content: regarding 98.2%, 0.3210 mol), methyl tetrahydrofuran: 300ml, Dry salt methyl sulfate: 50.8 g (web content: 97.3%, 0.3689 mol). Mixing was started, as well as the outer wall surface of the three-neck flask was warmed with an electrical home heating mantle, and the reaction was refluxed for 5.0 to 8.0 hrs. After the response was finished, it was cooled down to space temperature.
5) Post-processing: After cooling, filter, and the filter cake is constructed from salt sulfate for detailed utilization. The filtrate was transferred to a 500ml three-necked flask to recuperate methyl tetrahydrofuran. After recovery, 4-Methylanisole was obtained: 38.5 g, spotted material: 97.2%, return: 95.5%.
