Bisulphates

Li J and Abruna FI D 1997 Coadsorption of sulphate/bisulphate anions with Fig cations during Fig underpotential deposition on Au (111) An In situ x-ray diffraction study J. Phys. Chem. B 101 244-52... 

The hydrogensulphates (or bisulphates) containing the ion HSO4, are only known in the solid state for the alkali metals and ammonium. Sodium hydrogensulphate is formed when sodium chloride is treated with cold concentrated sulphuric acid ... 

Method 2 (from potassium bromide and sulphuric acid). Potassium bromide (240 g.) is dissolved in water (400 ml.) in a litre flask, and the latter is cooled in ice or in a bath of cold water. Concentrated sulphuric acid (180 ml.) is then slowly added. Care must be taken that the temperature does not rise above 75° otherwise a little bromine may be formed. The solution is cooled to room temperature and the potassium bisulphate, which has separated, is removed by flltration through a hardened Alter paper in a Buchner funnel or through a sintered glass funnel. The flltrate is distilled from a litre distilling flask, and the fraction b.p. 124 127° is collected this contains traces of sulphate. Pure constant boiling point hydrobromic acid is obtained by redistillation from a little barium bromide. The yield is about 285 g. or 85 per cent, of the theoretical. 

The mechanism of the aromatic substitution may involve the attack of the dectrophilic NOj" " ion upon the nucleophilic aromatic nucleus to produce the carboniiim ion (I) the latter transfers a proton to the bisulphate ion, the most basic substance in the reaction mixture... 

Pyruvic acid is conveniently prepared by the distillation of tartaric acid with a dehydrating agent, such as potassium bisulphate ... 

The 5 3 mechanism does not satisfactorily account for the kinetic observations, as can be seen when the nature of the base (B) in nitrations is recalled it would most likely be a nitrate or bisulphate anion. 

In originally considering the 5 3 mechanism, involving base catalysis, Bennett, Brand, James, Saunders and Williams were trying to account for the small increase in nitrating power which accompanies the addition of water, up to about 10%, to sulphuric acid. The dilution increases the concentration of the bisulphate ion, which was believed to be the base involved (along with molecular sulphuric acid itself). The correct explanation of the effect has already been given ( 2.3.2). 

The esterified stream, which may contain inhibitors to prevent premature polymerisation, is then passed to a stripping column which separates the methyl methacrylate, methanol and some water from the residue made up of sulphuric acid, ammonium bisulphate and the remainder of the water. The methyl methacrylate is subsequently separated and purified by further distillation. 

A terpene yielding isofenchyl alcohol on hydration, which Wallach considers to be one of the fenchenes, was artificially prepared by converting nopinone into a hydroxy ester by means of bromoacetic ester and zinc-dust. The hydroxy ester is dehydrated by potassium bisulphate, and so yields an unsaturated ester, which on saponification yields an acid from which the terpene results by distillation. This fenchene has the following characters —... 

Komppa and Eoschier now propose a revision of the nomenclature of the fenchene terpenes, Wallach s D-fenchene being termed a-fenchene, D-Z-fenchene becoming Z-o-fenchene, and D-d-fenchene becoming d-a-fenchene. The fenchene obtained by Bertram and Helle s method, by dehydrating fenchyl alcohol with potassium bisulphate, is now termed y8-fenchene. This nomenclature is certainly preferable as it contains no suggestion that the two bodies are identical in chemical constitution, nor is there any particular evidence that D-Z-fenchene and L-Z-fenchene are not the same actual terpene, and equally so in the case of D-d-fenchene and L-d-fenchene. 

The latest contribution to the chemistry of this abstruse subject is contained in papers by Komppa and Eoschier, and by Eoschier. They have obtained a fenchene l>y treating methyl-/3-fenchocamphorol with potassium bisulphate, which is the inactive form of )8-fenchene, mixed with a small amount of a terpene they term y-fenchene. /3-fenchene (identical with D-(f-fenchene of Wallach), and y-fenchene have the following constitutions —... 

This oil is heated at 110° C. with a solution of bisulphate of sodium of 11° Beaume (42 kg. for 360 litres of water) in a vessel with a mixing device until the samples distilled every day show that the first running, which has an unpleasant smell, has reached the density of 0 936. This happens after about eight days (the first itinnine being about 8 kg.). 

Thus it can be seen that evidence for the A-l mechanism, even if one accepted that this followed from a linear rate coefficient-acidity function correlation, was scant. On the other hand, there have been a very large number of carefully documented studies in which general acid catalysis has been observed leading to the A-Se2 mechanism for the reaction, or it has been shown that the conclusions from an acidity function dependence are not rigorous. One such study has already been described above, and Satchell478 also found that in the detritiation of [4,6-3H2]-l,2,3-trimethoxybenzene by potassium bisulphate, dichloro- and tri-fluoroacetic acids, plots of log kl versus —H0 were linear with a slope of ca. 1.0... 

The data in Table 191 show a large difference in entropy of activation for reaction of the 4-methoxy compound in the three acids. The difference in the data for perchloric and sulphuric acids was again thought to arise from a significant amount of reaction in the latter occurring via bisulphate anion. This anion was proposed as being insufficiently electrophilic to react except by coordination with the side chain, as in scheme (2S0)... 

Magnesium fluorosilicate Mercuric chloride Nickel chloride Nickel sulphate Potassium bisulphate Potassium bisulphite Potassium sulphite Silver nitrate... 

Sodium aluminium sulphate Sodium bisulphate Sodium hypochlorite Sodium perchlorate Sodium thiocyanate Stannic ammonium chloride Stannic chloride Stannous chloride Uranyl nitrate Zinc chloride Zinc fluorosilicate... 

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