Different association-parameters of primary, secondary, and tertiary alcohols dissolved in CCI, and C6H6 were compared with their values in cyclohexane. The parameters are the monomer-fraction a, , the fraction of the open entities relatively to the formal number of molecules Z a n , o , the average degree of association of one molecule E,, the fraction of the number of all the real entities relatively to the formal number of molecules Lan and the mean association-constants k , of a monomer to a given entity (monomer, dimer ...). The experimental methods were the determination of the partition-coefficients of the alcohols between the organic solvent and water and the infra-red spectrometry. This study shows that the concurrence the solvents CCll and C6H6 oppose to the auto-association o f the alcohols is not the same for all the alcohols. These differences in solvent-effects lead in some cases to an inversion in the sequence of the alcohols ordered after their association-parameters in benzene and in CCI, relatively to this sequence in C6H, *.
When alcohols are dissolved in benzene, they are, at a given concentration, less associated than in cyclohexane or in other saturated hydrocarbons. This effect was discovered as early as 1933 by R. Freymann [I]. It can be ascribed to the formation of 0-H .. bonds between the alcohol and the electrons of the benzene-ring: