Claims
- 1. A process for purifying crude acetonitrile having a UV absorbance at 200 nm of from 0.1 to 5 comprising:
- (1) a step of contacting crude acetonitrile with an ozone-containing gas in an amount from 1 to 10,000 times the volume of the crude acetonitrile,
- (2) a step of contacting the acetonitrile from step (1) with an anion exchange resin, wherein the contact temperature of the acetonitrile and the anion exchange resin is from -40.degree. to 80.degree. C.,
- (3) a step of removing low-boiling compounds and high-boiling compounds from the acetonitrile.
- 2. A process as claimed in claim 1, wherein said crude acetonitrile has an absorbance of not less than 0.1 at a wavelength of 200 nm and the purified acetonitrile has an absorbance of not more than 0.05 at a wavelength of from 200 to 400 nm.
- 3. A process as claimed in claim 1, wherein said crude acetonitrile is acetonitrile recovered as a by-product in the production of acrylonitrile or methacrylonitrile by catalytic ammoxydation of propylene, isobutene or t-butyl alcohol with ammonia and molecular oxygen.
- 4. A process as claimed in claim 2, wherein the nascent oxygen is nascent oxygen generated from at least one compound selected from a permanganic acid or a salt thereof, an oxyacid or a salt thereof, a peroxide, and an ozone-containing gas.
- 5. A process as claimed in claim 4, wherein said peroxide is selected from hydrogen peroxide, sodium peroxide, and barium peroxide.
- 6. A process as claimed in claim 4, wherein said oxyacid or a salt thereof is at least one selected from sodium hypochlorite, potassium hypochlorite, sodium hypoiodite, potassium hypoiodite, sodium hypobromite, potassium hypobromite, sodium chlorate, potassium chlorate, sodium iodate, potassium iodate, sodium bromate, potassium bromate, sodium perchlorate, potassium perchlorate, perchloric acid, periodic acid, sodium periodate, and potassium periodate.
- 7. A process as claimed in claim 2, wherein the contact with nascent oxygen is carried out at a temperature of from -40.degree. to 80.degree. C. in a batch system or a continuous system.
- 8. A process as claimed in claim 3, wherein the contact with nascent oxygen is carried out at a temperature of from -40.degree. to 80.degree. C. in a batch system or a continuous system.
- 9. A process as claimed in claim 7, wherein said nascent oxygen is an ozone-containing gas having an ozone concentration of from 0.01 to 5.0% by volume.
- 10. A process as claimed in claim 8, wherein said nascent oxygen is an ozone-containing gas having an ozone concentration of from 0.01 to 5.0% by volume.
- 11. A process as claimed in claim 9, wherein the contact with said ozone-containing gas is carried out in a batch system by feeding the ozone-containing gas in an amount from 1 to 10000 times as much as the volume of the crude acetonitrile from at least one nozzle into the liquid crude acetonitrile for a period of from 1 to 300 minutes.
- 12. A process as claimed in claim 10, wherein the contact with said ozone-containing gas is carried out in a batch system by feeding the ozone-containing gas in an amount from 1 to 10000 times as much as the volume of the crude acetonitrile from at least one nozzle into the liquid crude acetonitrile for a period of from 1 to 300 minutes.
- 13. A process as claimed in claim 9, wherein the contact with said ozone-containing gas is carried out in a batch system by feeding the ozone-containing gas until the ozone concentration in the exhaust gas reaches at least 80% of that of the gas fed.
- 14. A process as claimed in claim 10, wherein the contact with said ozone-containing gas is carried out in a batch system by feeding the ozone-containing gas until the ozone concentration in the exhaust gas reaches at least 80% of that of the gas fed.
- 15. A process as claimed in claim 9, wherein the contact with said ozone-containing gas is carried out in a continuous system in a packed tower or a plate tower by feeding the crude acetonitrile and the ozone-containing gas from the top and the bottom of the tower, respectively, at a gas to liquid volume ratio of from 1 to 10000.
- 16. A process as claimed in claim 10, wherein the contact with said ozone-containing gas is carried out in a continuous system in a packed tower or a plate tower by feeding the crude acetonitrile and the ozone-containing gas from the top and the bottom of the tower, respectively, at a gas to liquid volume ratio of from 1 to 10000.
- 17. A process as claimed in claim 2, wherein the contact with the solid base is carried out at a temperature of from -40.degree. to 80.degree. C.
- 18. A process as claimed in claim 3, wherein the contact with the solid base is carried out at a temperature of from -40.degree. to 80.degree. C.
- 19. A process as claimed in claim 17, wherein said anion exchange resin is a porous or gel type strongly basic anion exchange resin having an OH type or C0.sub.3 type exchange group or a porous or gel type weakly basic anion exchange resin having a primary, secondary or tertiary amino group as an exchange group.
- 20. A process as claimed in claim 18, wherein said anion exchange resin is a porous or gel type strongly basic anion exchange resin having an OH type or CO.sub.3 type exchange group or a porous or gel type weakly basic anion exchange resin having a primary, secondary or tertiary amino group as an exchange group.
- 21. A process as claimed in claim 2, wherein said step of removing low-boiling compounds and high-boiling compounds is carried out by at least one of distillation and membrane separation.
- 22. A process as claimed in claim 3, wherein said step of removing low-boiling compounds and high-boiling compounds is carried out by at least one of distillation and membrane separation.
- 23. A process as claimed in claim 21, wherein said step of removing low-boiling compounds and high-boiling compounds is carried out in a plate tower or a packed tower under a pressure of from 0.5 to 10 atm.
- 24. A process as claimed in claim 22, wherein said step of removing low-boiling compounds and high-boiling compounds is carried out in a plate tower or a packed tower under a pressure of from 0.5 to 10 atm.
- 25. A process as claimed in claim 21, wherein said step of removing low-boiling compounds and high-boiling compounds is carried out in two distillation towers, in which low-boiling compounds are separated by a first tower, and high-boiling compounds are separated by a second tower.
- 26. A process as claimed in claim 22, wherein said step of removing low-boiling compounds and high-boiling compounds is carried out in two distillation towers, in which low-boiling compounds are separated by a first tower, and high-boiling compounds are separated by a second tower.
- 27. A process as claimed in claim 21, wherein said step of removing low-boiling compounds and high-boiling compounds is carried out in a single distillation tower, in which acetonitrile is introduced into the middle part of the tower, and low-boiling compounds and high-boiling compounds are separated from the top and the bottom of the tower, respectively, while recovering purified acetonitrile from the position higher than the position where acetonitrile is introduced.
- 28. A process as claimed in claim 22, wherein said step of removing low-boiling compounds and high-boiling compounds is carried out in a single distillation tower, in which acetonitrile is introduced into the middle part of the tower, and low-boiling compounds and high-boiling compounds are separated from the top and the bottom of the tower, respectively, while recovering purified acetonitrile from the position higher than the position where acetonitrile is introduced.
- 29. A process as claimed in claim 1, wherein each step is controlled by near infrared spectrophotometry.
Parent Case Info
This application is a continuation of PCT/JP93/00638 (filed May 14, 1993).
US Referenced Citations (8)
Foreign Referenced Citations (7)
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