Background and overview[1-2]
Metachloroperoxybenzoic acid is a commonly used oxidizing agent in organic synthesis. It can oxidize alkenes, carbonyl compounds, nitrogen-, sulfur-, phosphorus-, selenium-, iodine-containing compounds, imines, alkanes, active methylene, and enols. Silanes, etc., are widely used in chemical industry, medicine, agricultural chemicals and other fields.
Preparation[1]
A method for preparing m-chloroperoxybenzoic acid using phase transfer catalysis. Dissolve 3.91g m-chlorobenzoic acid in 180mL chloroform, and add 158g 5% (mass fraction, the same below) (pH=1) highly acidic Potassium manganate aqueous solution, then add 0.97g of phase transfer catalyst benzyltriphenylphosphine chloride, the molar ratio of m-chlorobenzoic acid to acidic oxidant and catalyst is 1:2:0.1, control the reaction temperature at 15°C, and react for 8 hours , the reaction is completed, extract, separate the organic phase, add anhydrous magnesium sulfate to dry, filter and separate the residue to obtain m-chloroperoxybenzoic acid/chloroform solution, with a yield of 85.1%.
Refining method[2]
1) Put the crude m-chloroperoxybenzoic acid into the reaction kettle, and then dehydrate, the dehydration rate is 85%;
2) After dehydration, add 1,4-dioxane and stir to fully mix the materials;
3) After thorough mixing, raise the temperature and control the temperature between -8°C. After keeping the temperature for 0.25 hours, add ethanol and slowly heat up and stir. When the temperature reaches 35°C, start recovering ethanol;
4) After recovering the ethanol, cool it to 10°C, add stabilizer, discharge and centrifuge to remove the solvent, and then dry it under negative pressure.
Apply[3-4]
CN201710478721.7 discloses a synthesis process of minoxidil. Minoxidil can directly act on the blood vessel wall, dilate arterioles, reduce peripheral resistance, lower blood pressure, and can also increase heart rate and cardiac output. , but its antihypertensive effect is more significant and longer-lasting than hydralazine. The process is as follows: first, 2,4-diamino-6-chloropyrimidine is oxidized with m-chloroperoxybenzoic acid to obtain the intermediate 2,6-diamino-4-chloropyrimidine-1-oxide, and then the intermediate 2,6- Diamino-4-chloropyrimidine-1-oxide and piperidine are condensed under alkaline conditions to form crude minoxidil. Finally, crude minoxidil is crystallized in isopropyl alcohol and purified to obtain refined minoxidil. Your finished product. The process principle of the invention is simple, the operation is convenient, the product yield is high and the purity is good.
Epoxides can be polymerized to form cured products with excellent electrochemistry, heat and moisture resistance. Among them, diepoxide is a key intermediate and the polymer formed after polymerization can be widely used in resists, coating agents, inks, adhesives, sealants, encapsulants, composite materials, optical materials, electronic materials, etc. Multiple areas. CN201911328227.8 discloses a one-pot method for preparing diepoxide. The method includes the following steps: S1. Epoxidation reaction: add the diene into the reactor at low temperature, slowly add m-chloroperoxybenzoic acid solution dropwise, and react to obtain a crude diepoxide solution; S2. Separation and purification: Go to Add a reducing agent aqueous solution to the crude diepoxide solution, perform reduction reaction, extract to separate the organic phase, neutralize, extract to separate the organic phase, wash with water, remove water, filter, and distill the filtrate under reduced pressure to obtain the diepoxide. The invention avoids the high vacuum distillation of the solvent in the traditional process, and does not need to separate the solid raw material of m-chloroperbenzoic acid. The diepoxide is obtained through the one-pot reaction of diene and m-chloroperbenzoic acid solution, which reduces the process operation. difficulty, increased safety, and the purity of the prepared diepoxide is above 91%, and the yield is above 95%, which is beneficial to large-scale industrial production.
References
[1][Chinese invention] CN201911330267.6 A method for preparing m-chloroperoxybenzoic acid using phase transfer catalysis
[2][Chinese invention] CN201110199023.6 m-chloroperoxybenzoic acid refining process
[3][China Invention] CN201710478721.7 A synthesis process of minoxidil
[4][Chinese invention] CN201911328227.8 A one-pot method for preparing diepoxide
