Fluoroacetyl chloride toxicity

It is interesting to compare the toxicity of fluoroacetyl chloride with the isomeric chloroacetyl fluoride. The former possessed a toxicity comparable to that of methyl fluoroacetate, whereas the latter was relatively non-toxic. This is readily understandable in that fluoroacetyl chloride gives the toxic fluoroacetic acid, whereas chloroacetyl fluoride hydrolyses to chloroacetic acid and the relatively non-toxic (at the concentrations employed) hydrogen fluoride. Fluoroacetyl fluoride also possessed a toxicity comparable with that of fluoroacetyl chloride or of methyl fluoroacetate, again showing that the COF group contributed practically nothing. Acetyl fluoride was also non-toxic. 

Fluoroacetic anhydride, which was readily prepared by the action of fluoroacetyl chloride on sodium fluoroacetate, is a mobile liquid of b.p. 89°/12 mm. It is a useful fluoroacetylating substance. It was rather more toxic by inhalation than M.F.A. (weight for weight). 

In view of the fact that fluoroethanol is as toxic as methyl fluoroacetate (or as fluoroacetic acid), it seemed worth while preparing a compound in which the active parts of these molecules were combined, in the hope of obtaining a compound of increased potency. Such a compound is 2-fluoroethyl fluoroacetate, first prepared and described by us in 1943.1 This ester was readily prepared by the action of fluoroacetyl chloride on fluoroethanol. It is a stable, mobile liquid possessing an extremely faint odour. 

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