Claims
- 1. In a process for removing formic acid from a crude mixture thereof with a carboxylic acid selected from the group consisting of lower fatty acids other than formic acid by reacting the formic acid component of the mixture with a carboxylic anhydride, a compound forming an anhydride with a carboxylic acid, or a mixture thereof, the improvement which comprises carrying out the reaction at a temperature of from about 20.degree. C. to 300.degree. C. in the presence of an acid catalyst which is a mineral acid, a sulfonic acid, an acidic salt of a mineral acid or a heterogeneous acid catalyst selected from the group consisting of acidic ion exchange resins in the H.sup.+ form and acid-activated bentonites and zeolites.
- 2. The process defined in claim 1 in which the acid catalyst is sulfuric acid.
- 3. The process defined in claim 1 in which the reaction is carried out at a temperature of from 100.degree. C. to 200.degree. C.
- 4. The process as defined in claim 1 in which the acidic catalyst is an acidic salt of a mineral acid.
- 5. The process as defined in claim 1 in which acetic acid containing formic acid as an impurity is reacted with acetic anhydride.
- 6. The process defined in claim 1 in which the acid catalyst is an acidic ion exchange resin in the H.sup.+ form.
- 7. The process defined in claim 6 in which the acid catalyst is a macroreticular polystyrene-divinylbenzene resin having sulfonic acid groups in the H.sup.+ form.
- 8. The process as defined in claim 1, wherein said lower fatty acid is acetic acid.
- 9. The process defined in claim 8 in which acetic acid containing formic acid as an impurity is reacted with acetic anhydride, ketene or a mixture thereof.
- 10. The process as defined in claim 1, wherein said lower fatty acid is propionic acid.
- 11. The process defined in claim 1 in which propionic acid containing formic acid as an impurity is reacted with propionic acid anhydride.
Priority Claims (1)
Number |
Date |
Country |
Kind |
2258441 |
Nov 1972 |
DE |
|
Parent Case Info
This is a continuation-in-part of application Ser. No. 419,291 filed Nov. 27, 1973, now abandoned.
US Referenced Citations (1)
Number |
Name |
Date |
Kind |
2770585 |
Smith et al. |
Nov 1956 |
|
Foreign Referenced Citations (1)
Number |
Date |
Country |
807,987 |
May 1974 |
BE |
Continuation in Parts (1)
|
Number |
Date |
Country |
Parent |
419291 |
Nov 1973 |
|