1- bromo-3-fluoropropane

Interpretation of tiie ratio of capture of competing nucleophiles has led to the estimate that bromonium ions have lifetimes on the order of 10 s in methanol. This lifetime is about 100 times longer than fliat for secondary caibocations. There is also direct evidence for the existence of bromonium ions. The bromonium ion related to propene can be observed by NMR spectroscopy when l-bromo-2-fluoropropane is subjected to superacid conditions. The terminal bromine adopts a bridging position in the resulting cation. 

With Freon 112 or 113 as a solvent, fluonnation of pnmary butyl halides with bromine trifluonde can give mixtures of primary and secondary fluorides When 1,4 dibromobutane is the substrate, 93% l-bromo-4-fluorobutane and 1% 1-bro-mo-3-fluorobutane is obtained, with 1,4 dichlorobutane, the product contains 65% l-chloro-3-fluorobutane and 35% 1-chloro 4 fluorobutane When 4-bromo- or 4-chlorobutyl trifluoroacetate is used, the ratio of 4-fluorobutyl tnfluoroacetate to 3 fluorobutyl trifluoroacetate is 1 4 The effect of solvent is measured in another set of experiments When the reaction of bromine trifluonde and l,3-dichloro-2-fluoropropane in either Freon 113 or hydrogen fluoride is allowed to proceed to 40% conversion, the product mixture has the composition shown m Table 1 [/O] When 1 chloro 2,3-dibromopropane is combined with one-third of a mole of bromine trifluonde, both 1 bromo 3 chloro-2-fluoropropane and l-chloro-2,3-di-fluoropropane are formed [//] (equation 10)... 

The electrolyte consisted of anhydrous hydrogen fluoride with 0.1 M sodium fluoride. The anode was a platinum grid (3 cm2), the cathode material was also platinum and the reference electrode was Cu/CuF2. The electrolysis of 1-bromopropane was carried out at a potential of 1.65 V. The products were 2-fluoropropane(20%), 1, l-difluoropropane(30 %), and l-bromo-2-fluoropropane (40 %), as well as lesser amounts of 1,2-dibromo-3-fluoropropane, 2-bromo-l, 1 -difluoropropanc, 1,2-dibromopropane, and 1,3-dibromopropane. 

There is direct evidence for the existence of bromonium ions. The bromonium ion related to propene can be observed by NMR when l-bromo-2-fluoropropane is subjected to superacid conditions. 

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