Trifluoroacetic acid → Trifluoroacetic acid

Temperature

-78 °C

TFA and TFM were obtained from Mallinckrodt and Halocarbon Products, acetic acid and anhydride from J. T. Baker and diketene from Aldrich Chemical. Ketene was prepared by two methods: Method A: Diketene was passed through a heated tube at a temperature between 500-600° C. The formed gas was condensed in a dry ice bath at −78° C., redistilled into a calibrated cold finger, measured based on a density of 0.65 g/ml and transferred under reduced pressure to a reaction vessel also chilled to −78° C. Method B: Acetic acid was passed through a heated tube with quartz packing at a temperature between 500-600° C. The formed gas was trapped in a series of scrubbers through which TFA was circulated at a rate approximately 4.5 ml per minute. The TFA solution of Ac-TFA obtained from the scrubbers was characterized by 13C NMR to determine the relative amounts of acetic acid, acetic anhydride, acetyl trifluoroacetate and trifluoroacetic anhydride.

1. customcondensed in a dry ice bath at −78° C.
2. distillationredistilled into a calibrated cold finger
3. customtransferred under reduced pressure to a reaction vessel
4. customMethod B: Acetic acid was passed through a heated tube with quartz packing at a temperature between 500-600° C

ORD record

ord-3ce69ed69ad34320a9ab728f58da05d3

Source dataset

uspto-grants-2001_06

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US06248923B1