1 Carbon dioxide haloform

However, the reaction products were not, apparently, identified20f. Trifluoro-acetate and trichloroacetate were extracted and precipitated from the acidified solution as their silver and mercurous salts, respectively, and the carbon dioxide produced by pyrolysis of these was analyzed in the mass spectrometer. So the occurrence of side-reactions leading to other carboxylate salts cannot be completely ruled out. Just one possibility is the halodecarboxylation of the anion, followed by hydrolysis of the dihalocarbene or haloform produced, to formate, viz. 

Attempts to apply the thermal decarboxylation reaction in the liquid phase to aromatic halofor-mic acid esters have shown that their reaction is different from that ol the aliphatic haloformates. It was found that evolution of carbon dioxide occurs, but only high boiling products could be isolated.136 On heating in the presence of aromatics and Lewis acids, aryl chloroformates do not react to give chlorinated aromatics with concomitant decarboxylation, but undergo a Friedel-Crafts reaction to give phenyl benzoates.137 Under similar conditions phenyl fluoroformate undergoes only polymerization and carbonate formation.137... 

Depending on the catalyst system and the chosen reaction conditions, aliphatic and aromatic alcohols can in general act as substrates for oxidative carbonylations. In principle this reaction type can occur in the presence of metal ions which are able to oxidize CO in the presence of an alcohol function. As already mentioned above, it is also here necessary to carry out the reaction in the presence of a suitable reoxidant in order to establish a catalytic cycle process. Preferably that may be another metal salt, for example CuCU- Typical products and side products which are observed in the oxidative carbonylation of alcohols are alkyl and aryl carbonates, oxalates, formates, haloformates, acetals, and carbon dioxide. 

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