Background and overview[1]
M-Creyl acetate is mainly used as an intermediate for pharmaceutical and chemical synthesis.
Preparation[1
The preparation of m-creyl acetate is as follows:
The preparation steps are: first, take 21.6g of m-cresol in a 100ml Erlenmeyer flask, and then add 15ml of methylene chloride as a solvent into the Erlenmeyer flask; secondly, under the conditions of an ice water bath at 0 to 5°C, use constant pressure Add 15.7g acetyl chloride reagent dropwise into the system from the dropping funnel, and allow the reaction to fully react for 30 to 60 minutes; again, continue the low-temperature reaction in an ice water bath of 0 to 5°C for 60 minutes and then start to heat up, and the system temperature is controlled at 60±5°C. , react for 2 to 3 hours, and pass the tail gas generated by the reaction into the sodium hydroxide aqueous solution for absorption; finally, take out the solid mixture generated after the reaction in the Erlenmeyer flask, and use a rotary evaporator to remove the unreacted solvent methylene chloride in the solid mixture , to prepare m-toluyl acetate.
Apply[1-3]
M-Creyl acetate is mainly used as an intermediate for pharmaceutical and chemical synthesis. Examples of its application are as follows:
1) Preparation of m-carboxyphenyl acetate. The reaction equation is as follows:
The preparation steps are:
a. Put 7.5g of m-creyl acetate prepared in the previous step I into a 100ml Erlenmeyer flask, add 50ml of water and stir thoroughly, then add 5ml of glacial acetic acid, and heat the system to 60~80℃;
b. Weigh 243g of potassium permanganate, slowly add it in small amounts and multiple times to the m-creyl acetate system. After all the potassium permanganate is added, keep the system temperature at 50-80°C for 8-10 hours; After all the purple color in the system fades away, the system is heated to 90-110°C and reacts for 2-3 hours. After the reaction, the pH value of the system solution is measured to be 8±0.2. Filter the generated solution while it is hot. After filtration, use the filter used in the filtration process. Wash the cake 3 times with hot water and keep it for next use;
c. Use hydrochloric acid to adjust the pH of the filtrate obtained in step b to ≤ 1. The solution should remain free of precipitation or have trace amounts of precipitation. Then extract it with ethyl acetate. After extraction, use a rotary evaporator to remove the extractant in the mixture. That is, the solid product of m-carboxyphenyl acetate is obtained.
2) Prepare m-aminophenol. Meta-aminophenol is an important fine chemical raw material and organic intermediate, and is widely used in petrochemical industry, pesticides, medicines, dyes and other fields. So far, a variety of processes for synthesizing m-aminophenol have been developed, including the nitrobenzene method, the resorcinol aminolysis method, the m-nitrophenol electrolysis method, the aniline hydroxylation method, and the m-phenylenediamine hydrochloric acid hydrolysis method. , but most of them have the problems of backward technology, serious pollution, high cost, low yield and selectivity, and high equipment requirements.
Preparation of m-aminophenol from the prepared m-carboxyphenyl acetate has achieved good results: a. Add C9H8O4 reagent to the ethyl acetate solution and stir thoroughly until completely dissolved. Add thionyl chloride dropwise to the system under ice-water bath conditions. Incubate for 1±0.5 hours, raise the temperature to 60°C and then reflux; b. Under ice-water bath conditions, add triethylamine and hydroxylamine hydrochloride to the system, incubate for 2 hours and then raise the temperature to room temperature; c. Evaporate the solvent on a rotary evaporator Spin dry, then add water and potassium carbonate, and heat to 60-70°C for hydrolysis; d. Extract the solution with ethyl acetate, and use thin layer chromatography to determine whether the extraction is complete. After the extraction is completed, the finished product m-aminophenol is obtained.
3) Preparation of resorcinol.
Resorcinol is mainly used in rubber adhesives, synthetic resins, dyes, preservatives, pharmaceuticals and analytical reagents. Resorcinol is similar to phenol and cresol, and forms condensation polymers with formaldehyde, which can be used in the manufacture of Viscose silk adhesive, wood glue and the bonding of vinyl materials and metals. Resorcinol is an intermediate for many azo dyes and fur dyes. It is also a pharmaceutical intermediate and the raw material of para-nitrosalicylic acid. . Resorcinol also has bactericidal properties and can be used as a preservative.
The solution is: prepare m-creyl acetate, m-carboxyphenyl acetate and m-aminophenol in sequence, and then use the prepared m-aminophenol to prepare resorcinol: a. Dry the prepared m-aminophenol Weigh 1.09g, weigh 50ml of water, and weigh 2.5ml of concentrated hydrochloric acid. Mix the reaction raw materials and raise the temperature to 35°C, and stir thoroughly until the solution is clear; b. Weigh 0.828g of solid sodium nitrite and dissolve it in the water; c. Under ice-water bath conditions, slowly add the sodium nitrite solution dropwise into the system; d. Maintain the ice-water bath conditions, and after sufficient stirring, heat the system to 30-40°C and continue the reaction; e. Extract the reacted solution with ethyl acetate , use a rotary evaporator to spin the completely extracted reactant to dryness, and obtain resorcinol solid.
Main reference materials
[1] CN201710803461.6 A process for preparing m-carboxyphenyl acetate
[2] CN201710803486.6 A process for preparing m-aminophenol
[3] CN201710803479.6 A process for preparing resorcinol
微信扫一扫打赏
