Reaction with aluminium fluoride

G. S. Serullas treated potassium chlorate with an excess of hydrofluosilicic acid the clear liquid was decanted from the sparingly soluble potassium fluosilicate, the soln. evaporated below 30°, and filtered through glass powder J. J. Berzelius evaporated the acid liquid mixed with finely divided silica below 30° in air, or over cone, sulphuric acid and potassium hydroxide in vacuo. The excess of hydrofluoric acid was volatilized as silicon fluoride, and the clear liquid was then filtered from the excess of silica. R. Bottger treated sodium chlorate with oxalic acid whereby sparingly soluble sodium oxalate was formed J. L. Wheeler, and T. B. Munroe treated sodium chlorate with hydrofluosilicic acid and M. Brandau treated potassium chlorate with aluminium sulphate and sulphuric acid and precipitated the alum so formed with alcohol. Chloric acid is formed in many reactions with hypochlorous and chlorous acid for example, it is formed when an aq. soln. of chlorine or hypochlorous or chlorous acid decomposes in light. It is also formed when an aq. soln. of chlorine dioxide stands in darkness or in light. A mixture of alkali chlorate and chlorite is formed when an aq. soln. of an alkali hydroxide is treated with chlorine dioxide. 

Cleavage of a carbon-fluorine bond can be induced by reaction with a Lewis acid (see Chapter 4, Section VIC). In Friedel-Crafts alkylations, aUcyl fluorides are more reactive than the chlorides [37] with, for example, aluminium halides or boron halides as catalysts (Figure 5.17). 

Phosgene can be used as the starting material for the preparation of other potentially useful carbonyl halides and carbonyl pseudohalides. Reaction of phosgene with fluorspar, for example, gives COCIF (see Section 9.1.1 and Chapter 16). With aluminium(III) bromide, COBrj is formed (Section 9.1.2.6). Reaction of COClj with HF gives COFj (see Section 9.10.4 and Chapter 13), reaction with silver cyanide gives carbonyl dicyanide, CO(CN)j (Section 9.1.7), whereas reaction with a mixture of sodium fluoride and HCN gives the mixed carbonyl halide pseudohalide, COFCN (Section 9.1.7 and Chapter 13). The chemistry of these... 

Sarin can be made by more than one method, but in the usual large scale route chloromethane, phosphorus trichloride and aluminium chloride, and then water react to give methylphosphonic dichloride this, on treatment with hydrogen fluoride (or sodium fluoride), gives a mixed chlorofluoride, which, by reaction with isopropyl alcohol, pelds Sarin (Figure 3). 

Sulphonyl halides, other than fluorides, have also been produced by halide exchange. Thus, sulphonyl chlorides may be made from the fluoride by refluxing with aluminium trichloride622,623. Sulphonyl bromides may be prepared from the sulphonyl chloride by reaction with sodium sulphite and base, followed by bromine (equation 158)624... 

In the last decade the chemistry of aluminium salts hydrolysis related to the application of the products of their partial hydrolysis in coagulation has been studied in detail [5]. It has been found that as well as the pH value, temperature, precipitate ageing and solution, the composition of the hydrolysis product also depends on the initial ratio of the concentration of OH ions and aluminium, as well as on the rate of the base addition. The hydrolysis of aluminium salts influences a number of side reactions depending on the overall composition of water, since aluminium forms complexes with other ligands, such as sulphate, phosphate and fluoride. 

A variety of papers on substitution reactions at aluminium(iii) in aqueous media have appeared. Complexation with 5-nitrosalicylic acid has been studied and compared with related studies involving other salicylic acid derivatives. It seems possible that the substitution process may be associative in character. There has been an investigation of the kinetics and equilibria of the reactions with Semi-xylenol Orange and Semi-methylthymol Blue. The latter two reactions involve a pre-equilibrium step, followed by a substitution stage in which several outer-sphere water molecules are removed. The relative reactivities of three different reaction pathways are [HaL]"- -[A10H] +> [HaL] "- -[A10H] +> [HaL] -- -Al +. The kinetics of complexation of aluminium(iii) with fluoride are... 

The sodium beryllium fluoride product is soluble in water and can be leached out, together with some aluminium, excess sodium silicofluoride, and small amounts of other impurities. Unfortunately a high proportion of the valuable fluorine is lost as the gaseous and highly toxic silicon tetra-fluoride, or as undissolved sodium aluminium fluoride. However, the escape of volatile silicon tetrafluoride can be prevented if a small amount of sodium fluoride is present with the sodium silicofluoride, owing to the reaction... 

An alternative fluoride breakdown process for beryl was used during the 1939-45 war by the Sappi Company in Italy. This was based upon the reaction with sodium hydrogen fluoride (NaF.HF) at a temperature of about 680°C. The fluoride reagent is mixed with the ground ore and made into briquettes with a little water, ready for firing in the breakdown furnace. The reaction converts the beryllium to a complex fluoride, believed to be 3NaF.2Bep2, without fluorination of the aluminium and silicon components. 

Propargyltrimethylsilane (162) reacts with saturated aldehydes and ketones in the presence of a catalytic quantity of tetra-n-butylammonium fluoride to produce a-hydroxyallenes U63). ° a,/3-Unsaturated or aromatic aldehydes give products contaminated with /3-hydroxyacetylenes. Analogous reactions with l-trimethylsilylbut-2-yne are preferably performed at low temperatures (-60 °C) with titanium tetrachloride as catalyst. Propargyltrimethylsilane also reacts with acid chlorides at low temperatures and in the presence of aluminium chloride to give moderate yields of a-allenic ketones (164). ... 

Extending this reaction to anisole as substrate, no aldehyde product was observed, while extensive de-alkylation of anisole to phenol occurred (Run 3). The important role of an added Bronsted acid (hydrogen fluoride) was confirmed as some aldehyde product was obtained from anisole in the presence of aluminium trichloride together with HF (Run 4). 

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