Solvents sulfuric acid

In the sulfuric acid solvent system, compounds that enhance the concentration of the solvo-cation HSO4- will behave as bases and those that give rise to H3S04 will behave as acids (p. 425). Basic solutions can be formed in several ways of which the following examples are typical ... 

The Sulfuric Acid Solvent System R. J Gillespie and E. A. Robinson... 

Gillespie, R. J., and Robinson, E. A. The Sulfuric Acid Solvent System, in Emeleua and Sharpe s Advances in Inorganic Chemistry and Radiochemistry, Yol. I., 386-424, Academic Press Inc., New York (1959). 

Possible methods of determining the extent of protonation include absorption spectroscopy at a wavelength for which species with n and fir-1 protons have different extinction coefficients, freezing point depression, and electrical conductivity (15). Of these, we have utilized only spectroscopy, which has the disadvantage that only the equilibrium constants for the most highly protonated states are accessible if, as is usual, the species with low protonation are insoluble. In this method, the extinction coefficient c of the compound is determined as a function of the H2SO4 content in the sulfuric acid solvent and correlated with the Hammet acidity function H0 (18) to give the pKB value of the protonated species,... 

The inorganic chemistry of the sulfuric acid solvent system has not yet been as extensively studied as that of some other solvents such as liquid ammonia, but a sufiBcient variety of certain classes of compounds has now been investigated for it to be possible to give a reasonably systematic account of their behavior. 

The conclusion that the boron tetra (hydrogensulfate) ion is formed in these solutions is of great interest since, as it apparently does not undergo solvolysis, the corresponding acid HB (HSO ) 4 must be a strong acid in the sulfuric acid solvent system, and must be extensively ionized according to Eq. (55) above. The solutions formed by dissolving boric... 

Moodie, Schofield and Weston have also commented on this point. They note that the selectivity observed in the reactions of the activated aromatic compounds can be quite readily rationalized without requiring an attractive Interaction in the encounter complex. Inasmuch as the energy barrier for separation of the encounter complex may exceed 3 kcal mole. in the sulfuric acid solvents, there is an ample energy range for selectivity in the formation of the benzenonlum ion. 

In the dry sulfuric acid solvent, it is possible that oxidation step proceeds before C-H activation. DFT calculations showed that oxidation of L2PtCl2 (reaction Cl) is around 20 kcal/mol more endothermic than that of L2PtCl(CH3) (reaction A2). This is reasonable as CH3 is a better electron donor than Cl. Further calculations indicated that oxidation of PtCl2(bpym) (23.4 kcal/mol) is less favorable than oxidation of PtCl2(NH3)2 (16.8 kcal/mol), and protonation of bpym further disfavors the oxidation step. The calculations showed that C-H activation on Pt (IV) (reaction C2) is thermo-neutral (AG(s, 453 K) = 0.6 kcal/mol) for L2 = (NH3)2 and mildly exothermic for the bpym ligand (—1.6 to —9.1 kcal/ mol). Compared to reaction Al, this indicates that higher oxidation state of Pt is in favor of the C-H activation. Based on the thermodynamics, it was inferred that oxidation-before-activation pathway (Pathway 3 Cl, C2, El) is preferable over the... 

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