Sulfur tetrafiuoride fluorides with

Reaction of Carbonyl Compounds with Sulfur Tetrafiuoride-Hydrogen Fluoride... 

The stereochemical outcome of the overall reaction is interpreted as the consequence of a stepwise fluorination.4-5 The first fluorine comes in via an SN2-type substitution of the cyclic intermediate 4 with inversion. The second fluorine is introduced with retention from the intermediate 7, which is formed by the action of hydrogen fluoride and sulfur tetrafiuoride on intermediate fluorosulfite 5 via 6. 

Thereare a limited number of examples of the reaction of nitro alcohols with sulfur tetrafiuoride. In each case the reaction was performed with additional hydrogen fluoride present. With these modifications relatively drastic conditions must be used and yields are low to moderate, depending on the substrate (Table 1). 

Hydrogen fluoride is produced worldwide in 10 ta by reaction of fluorspar with sulfuric acid (equation 1). The reaction is endothermic (AF/298 = 59kJmol ) and is carried out in rotary furnaces that produce up to 45td . The crude HF is scrubbed by H2SO4 and purified further by distillation as required. Silicon tetrafiuoride is a by-product from silicate impurities (equation 2) and is recovered as H2SiFe (equations). Another by-product, CaS04, is used in cement production and other applications. ... 

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