Study On Preparation Technique For High-purity Acetonitrile

With the development of chemical and medicine industry, as the mobile phase ofHPLC and the organic modifier, acetonitrile is widely demanded. The most commonhigh-purity acetonitrile purification method is the potassium permanganateoxidation-distillation process with the low yield and quantity of waste residues. Soinvestigation of a new purification process of chromatographic grade acetonitrilecomplies with both the development of the society and good economic benefit.In this research, using the new composite oxidant A as oxidant and testing theoxidation effect of oxidant A and potassium permanganate. The adsorb effect of13Xmolecular sieve, activated carbon and alumina were studied. The effect of differentprocess on acetonitrile’s quality was investigated. And the key impurity affecting thequality of acetonitrile was found out and proved the reaction conditions by experiment.The specific results are as follows:1) Compared the effect of the oxidation of potassium permanganate andantioxidant A, found in oxidation rate of A is faster than potassium permanganate andwithout waste residues. In the different combination of adsorbent, the combination of13X molecular sieve, activated carbon and alumina has better adsorption effect.2) Treated with oxidation at55℃during2h with low mass ratio of acetonitrileand oxidant(9:1) and consequent absorption of13X molecular sieve, activated carbonand alumina, the UV absorbance of acetonitrile decreased to0.843. Throughdistillation, the UV absorbance of acetonitrile can be decrease to0.043.3) Analyzed by GC, GC-MS and UV spectrophotometer, the key impurities werededuced as acetamide,3-aminocrotononitrile,4-Amino-2,6-dimethylpyrimidine and2,4,6-trimethyl-1,3,5-triazine. After inferring the mechanism of formation of the keyimpurities, the influent factors of generation of impurities were found out, which arepH, concentration of Fe3+and H2O and temperature. According to the above factors,the process of inhibiting impurities was prepared. The result can provide somereference for acetonitrile purification process designs.