REACTIVE DISTILLATION OF TRIFLUOROACETIC ANHYDRIDE

Raul LoboTrifluoroacetic anhydride (TFA anhydride) is an important reagent for the production of a novel class of bio-based surfactants. Current manufacturing methods using trifluoroacetic acid (TFA acid) have been completed on a lab-scale and involve the use of halogens or phosphorous pentoxide; there does not yet exist a continuous method for TFA anhydride synthesis from TFA acid without the aforementioned hazardous compounds. This thesis proposes a two-step process for recovering TFA acid from the production of bio-based surfactants, then synthesizing TFA anhydride through reactive distillation of TFA acid and acetic anhydride. First, it was found that TFA acid can be continuously distilled from the bio-based molecule precursor solution. In this step the heat applied for distillation drives the reaction to near completion, so reagents can be used in a 1:1:1 ratio to minimize waste. 95% of the TFA acid was recovered in a heterogeneous mixture with the heptane solvent, so it can be decanted and purified by distillation for use in TFA anhydride synthesis. Second, it was found that reactive distillation of a stoichiometric ratio of TFA acid and acetic anhydride (2:1) produced TFA anhydride with 94% purity and conversion of 9.0%. Finally, experimental results were used to construct a flowsheet in Aspen Plus, but the heterogeneous azeotropic nature of the first step prevented the use of simulation for predicting results after scale-up. Due to this complication and the low conversion of TFA acid to TFA anhydride, this process will require further investigation before it can be recommended for large-scale production.Chemical Engineerin