Acetonitrile purification process for ultrahigh performance liquid chromatography-mass spectrometer

An improved acetonitrile purification process, comprising the following steps:

• (1) adding an oxidizing agent into industrial acetonitrile containing impurities, water and acetonitrile to perform oxidation reaction, feeding the product into an adsorption and rectification tower for adsorption, and condensing the obtained tower top product of the adsorption and rectification tower to obtain a crude product, wherein a height of the adsorption and rectification tower is 7 to 30 m, and a pressure difference between the tower top and the tower bottom is 30 to 40 kPa;
• (2) adding a drying agent into the crude product for drying, heating and entering a reflux rectifying tower for total reflux after removing water, removing heavy component impurities at the tower bottom of the reflux rectifying tower, extracting and condensing light component impurities and acetonitrile at the tower top of the reflux rectifying tower to obtain a semi-finished product;
• and
• (3) removing 20 to 40 kg of semi-finished products extracted initially so as to remove the light component impurities, and filtering the semi-finished product extracted later to obtain a finished product, wherein a light transmittance of the finished product in ultraviolet rays of 200 to 260 nm is greater than or equal to 95%;
• wherein the number of the adsorption and rectification towers is two or three;
• wherein a filter membrane of the filtration comprises a macromolecular filter membrane and an ion exchange filter membrane;
• wherein the ion exchange filter membrane comprises an anion exchange filter membrane and a cation exchange filter membrane;
• wherein in the step (3), 20 to 40 kg of semi-finished products extracted initially are removed so as to remove the light component impurities, and the semi-finished products extracted later are sequentially filtered by the macromolecular filter membrane with a pore diameter of 150 to 250 nm, the ion exchange filter membrane and the macromolecular filter membrane with a pore diameter of 5 to 8 nm to obtain the finished product.