Solvent proton-acceptor

Proton-acceptor solvents are preferred at the donor solute separation and vice versa. 

The different solvation energetics of R and R- will also lead to errors in the bond dissociation enthalpies calculated with equation 16.33. For instance, in the case of phenol, whose interactions with proton-acceptor solvents (like DMSO) are obviously stronger than those for the phenoxy radical, a negative correction should be applied to the value of Z)//°(PhO-H) calculated from equation 16.33 (see also equation 16.32). It is probably unwise to ascribe the 7 kJ mol-1 difference between the electrochemical and the recommended DH° (PhO—R) value to the differential solvation effects. Although this discrepancy is in the correct direction, it lies within the suggested uncertainty of the method. 

Proton donor Proton acceptor Solvent Precipitation Ref. 

IR data have indicated93 that (29 R = Ac, cyclohexyl, MeS02, Me, H R7 = Pr, Bu R" = Me, Ph) exist as tautomer (29) in the crystalline state and in proton acceptor solvents and as tautomer (30) in proton donating solvents. 

The contribution of solvent-solute hydrogen bonding to selectivity [term (iii) in Eq. (34)] can be generalized for the presence of more than one basic or proton-acceptor solvent in the mobile-phase mixture ... 

A molecule of XH in adsorbed or nonsorbed phases Concentrations of XH in adsorbed and nonsorbed phases Complex of solute XH and proton-acceptor solvent C Concentrations of XHC in adsorbed and nonsorbed phases... 

Certain covalent acceptor chlorides such as molten iodine monochlorideii2 H3, arsenic(III)chlorideii and antimony(III)chlorideii5-H7 are suitable solvents for the formation of various chloro-complexes. Hydrogen chlorideii n may also be included in this group of solvents, but has been discussed in chapter IV as a protonic acceptor solvent. 

Just as certain chlorides are found to behave as useful solvents for the formation of chloro-complexes, bromo-complexes are formed in solutions of the corresponding bromides. The solvent behaviour of (for example) molten iodine mono-bromidei53 molten arsenic(III) bromide 54-156 aluminium (III) bromidei " or molten mercury(II) bromide -i has been described the chemistry in such solutions has been briefly re vie wed s 123,124 Hydrogen bromide is very similar, but has been discussed separately in this presentation as a protonic acceptor solvent (chapter IV). 

In all solvents, the fraction of free water was greater in both dilute solution and in neat water than it was in intermediate concentrations. Through the analysis of ternary mixtures, the amount of nonbonded water molecules was found to be negligibly small in proton-acceptor solvents. 

Bumeau, A., Near-infrared spectroscopic study of the stmctmes of water in proton acceptor solvents, J. Mol. Liq., 46, 99-127, 1990. 

There results the apparent paradox the generation of a conjugated system leads to a diminishing proportion of this as solvent polarity rises, the opposite behavior to that of their nonchelated analogs. And while the very large p term for 11 testifies to the strong interaction between OH and a proton acceptor solvent, OH in the chelates is trapped and no such interaction can occur. 

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