[Xylitol]

In a reaction using trifluoroacetic acid and sodium cyanate along with an alcohol, the corresponding carbamate is synthesized. Can anyone explain to me what the by products might be in this reaction?

Here is an example of the reaction:

Example 1 A mixture of 4.0 g. of 3-methyl-3-pentanol, 5.2 g. of sodium cyanate, 9.1 g. of trifiuoroacetic acid and 50 ml of tetrahydrofuran is stirred at 45 C. for two hours then neutralized by the addition of solid sodium carbonate. The mixture is concentrated, treated with water and filtered to give 3-methyl-3-pentyl carbamate

Here is a patent that describes it in more detail: https://www.google.com/patents/US3072710

The only obvious by product would be sodium trifluoroacetate. Would there be anything else?

Thanks.

[phth]

mixed anhydride.  Why?