Process for preparation of fluorinated carbonyl compounds

A process for preparing a fluorinated carbonyl compound, comprising

• (a) contacting a fluorinated ether which is generally described by formula as follows:
• ##STR3## where R is a methyl or ethyl radical;
• R.sup.1 is --F, --Cl, --Br, --SO.sub.2 F, --COF, --OCH.sub.3, --CN, --CO.sub.2 H, --CO.sub.2 CH.sub.3, --OC.sub.6 F.sub.5, or --OR.sup.4, --SR.sup.4 or --R.sup.4, where R.sup.4 is a linear or branched fluorinated alkyl radical of 1 to 8 carbon atoms, interruptible with either oxygen or keto groups, and optionally selected from the group consisting of --F, --Cl, --Br, --SO.sub.2 F, --COF, --OCH.sub.3, --CN, --CO.sub.2 H, --CO.sub.2 CH.sub.3, --OC.sub.6 F.sub.5 ;
• R.sup.2 is --H or --F;
• R.sup.3 is --F or --CF.sub.3 ;
• a is 1 or 2;
• b is 0 or 1;
• and
• a+b is 2 in a reaction mixture with tin tetrachloride at a first temperature which is at least about 90 percent of the boiling point of the fluorinated ether, until fluorinated carbonyl product begins to form;
• (b) upon the beginning of formation of fluorinated carbonyl product, heating said reaction mixture at a second temperature which is about 50 to about 90 percent of said first temperature;
• and
• (c) recovering a fluorinated carbonyl compound in at least a 35 weight percent yield.