Aerosol fluorination procedure

In a few cases extensive cleavage of the substrate molecule occurs The case documented [JS] involves beta cleavage of tetramethylorthocarbonate and tri-methylorthoacetate The mechanism of this reaction involves the formation of a radical which can form a more stable radical by eliminating a stable molecule by beta cleavage Interestingly tetramethylorthocarbonate seems to suffer less cleav age by the LTG method [9] Examples of beta cleavage during direct fluorination are shown in equahons 6-9, where AF is aerosol direct fluorination procedure... 

Although the concentration of fluorine is the most important quantity in the control of the reaction rate and must be maintained within certain limits, in practice the stoichiometry, the molecular fluorine to substrate H-atom molar ratio, is used to determine the reaction parameters leading to a successful and efficient perfluorination. AF is most successful when sublimable solids are introduced into the hydrocarbon evaporator unit of the aerosol fluorinator as solutions by a syringe pump. This now common procedure emphasizes the individual molecule s isolation as it is fluorinated using AF. No intermolecular reactions between solute and solvent have been observed Choice of the solvent is important as it must not boil at a temperature below the melting point of the solute in order to prevent solid deposition in the tubes feeding the evaporator. It must also fluorinate to a material easily separable from the solid reactant after perfluorination. In most cases it has been found that aliphatic hydrochlorocarbons are excellent choices, but that carbon tetrachloride and chloroform and other radical-scavenging solvents are not (sec ref 6). 

Experimental Procedure Aerosol Fluorination of Dimethoxy methane [29]... 

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