Reactions with Organic Fluorides

Chloroacetate esters are usually made by removing water from a mixture of chloroacetic acid and the corresponding alcohol. Reaction of alcohol with chloroacetyl chloride is an anhydrous process which Hberates HCl. Chloroacetic acid will react with olefins in the presence of a catalyst to yield chloroacetate esters. Dichloroacetic and trichloroacetic acid esters are also known. These esters are usehil in synthesis. They are more reactive than the parent acids. Ethyl chloroacetate can be converted to sodium fluoroacetate by reaction with potassium fluoride (see Fluorine compounds, organic). Both methyl and ethyl chloroacetate are used as agricultural and pharmaceutical intermediates, specialty solvents, flavors, and fragrances. Methyl chloroacetate and P ionone undergo a Dar2ens reaction to form an intermediate in the synthesis of Vitamin A. Reaction of methyl chloroacetate with ammonia produces chloroacetamide [79-07-2] C2H ClNO (53). 

The halogen fluorides are binary compounds of bromine, chlorine, and iodine with fluorine. Of the eight known compounds, only bromine trifluoride, chlorine trifluoride, and iodine pentafluoride have been of commercial importance. Properties and appHcations have been reviewed (1 7) as have the reactions with organic compounds (8). Reviews covering the methods of preparation, properties, and analytical chemistry of the halogen fluorides are also available (9). 

Similar insertion reactions are known with organic compounds. For example, the reaction with methyl fluoride yields fluorinated methylpolysilanes18 ... 

Several forms of highly reactive Mg metal are available they permit reaction with organic halides that otherwise could not react. Finely divided and highly reactive black Mg powder is prepared by the reduction of anhydr MgCl2 with potassium metal in refluxing THF . This powder forms a reagent even at —78°C or with aryl fluorides, which are otherwise unreactive ... 

Bone char is the oldest known agent for water defluoridation used since 1940s [7]. It has also been employed successfully for the removal of arsenic from groimd water. It is produced from animal bones (Fig. 4.4) that have imdergone calcination or pyrolysis processes. Though raw bones have some defluoridation value, it is low and limited by the various organics obstructing the interfaces where chemical reactions with the fluoride can take place [8]. 

Reaction with Organic Acids. Acyl fluorides can be prepared by the reaction of DAST with carboxylic acids in good to excellent yields. a-Hydroxy acids give a-fluoroacyl fluorides which hydrolyze on workup to form a-fluoro acids. Sulfur tetrafluoride, on the other hand, converts the carboxylic group into a trifluo-romethyl group. ... 

Organic fluorine compounds were first prepared in the latter part of the nineteenth century. Pioneer work by the Belgian chemist, F. Swarts, led to observations that antimony(Ill) fluoride reacts with organic compounds having activated carbon—chlorine bonds to form the corresponding carbon—fluorine bonds. Preparation of fluorinated compounds was faciUtated by fluorinations with antimony(Ill) fluoride containing antimony(V) haUdes as a reaction catalyst. 

The metallic salts of trifluoromethanesulfonic acid can be prepared by reaction of the acid with the corresponding hydroxide or carbonate or by reaction of sulfonyl fluoride with the corresponding hydroxide. The salts are hydroscopic but can be dehydrated at 100°C under vacuum. The sodium salt has a melting point of 248°C and decomposes at 425°C. The lithium salt of trifluoromethanesulfonic acid [33454-82-9] CF SO Li, commonly called lithium triflate, is used as a battery electrolyte in primary lithium batteries because solutions of it exhibit high electrical conductivity, and because of the compound s low toxicity and excellent chemical stabiUty. It melts at 423°C and decomposes at 430°C. It is quite soluble in polar organic solvents and water. Table 2 shows the electrical conductivities of lithium triflate in comparison with other lithium electrolytes which are much more toxic (24). 

Catalysis. Catalytic properties of the activated carbon surface are useful in both inorganic and organic synthesis. For example, the fumigant sulfuryl fluoride is made by reaction of sulfur dioxide with hydrogen fluoride and fluorine over activated carbon (114). Activated carbon also catalyzes the addition of halogens across a carbon—carbon double bond in the production of a variety of organic haUdes (85) and is used in the production of phosgene... 

Diazoketones [57] and esters [5S] react with hydrogen fluoride in organic solvents to give a-fluoroketones or esters, pyndinium poly(hydrogen fluoride) offers a convenient medium for the reaction (equation 13) [9]... 

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