Self-association of alcohols in nonpolar solvents

Abstract

Studies were made of solutions of 1-octanol and 1-butanol in n-decane using the infrared absorption of the first overtone of the O-H stretch vibrations of the monomer and selfassociation polymers. Evaluation was made on 1-octanol solutions from 5 to 100°, without making use of a priori self-association models. Evaluations were performed by three methods involving comparisons of: (I) the monomer absorbance and the total alcohol concention, (II) the monomer absorbance and the polymer absorbance, and (III) a combination of I and II. The following new assignments were made: (1) the end O-H of linear selfassociation polymers do not contribute significant absorbance at the monomer peak in the first overtone region; (2) the monomer molar absorptivity is constant with temperature;(3) the usual "dimer" peak at 1.528 µ cannot be due to a O-H • O-H dimer as its absorbance varies directly proportionally to that of the monomer (it is tentatively assigned to an alcohol-solvent interaction); (4) the remainder of the polymer absorption is assigned solely to tetramers; and (5) the tetramers give partially overlapping peaks which are due to O-H bonds in two different tetramers. Thermodynamic values indicate a linear and a cyclic tetramer. The linear with three bonds has a AH of -16.5 kcal/mole and the cyclic with four bonds has a AH of -20.3 kcal/mole. Thus within the limits of error, all O-H first overtone absorption is explained by assigning a monomer in equilibrium with two tetramers. This holds from 10-4 M to neat 1-octanol over a 95°t emperature range. Data from other workers for other alcohols in CCk are evaluated and found to be consistent with the present assignments. Much more self-association of alcohols was observed in n-decane than was observed in CCh. In particular, kinetic data involving alcohols are explained by the physical model described.N. Y" 1959.

Association and hydration of alcohols in low-dielectric solvents. I. n-Butanol

“…(12) for the association of methanol both in its vapour and in hexadecane, although it is at variance with other literature (7,33) which includes the tetramer in twoparameter models.…”

Electron trapping in alcohol clusters in γ-irradiated n-propanol–hydrocarbon glasses at 77 K

“…' Optical absorption bands were observed in the visible and ir region in a glassy alcohol-hydrocarbon mixture at 77 K, and they were, respectively, I ascribed to electrons (ehcp) trapped in the hydrocarbon matrix and those (ealCp) trapped in alcohol clusters (8), the existence of which was confirmed ' by the infrared absorption method (15)(16)(17). The formation of ealc-has also been proposed in liquid alcohol-hydrocarbon mixtures from a study of free ion yields, suggesting that a fraction of electrons generated in a hydrocarbon region are probably scavenged by alcohol clusters (1).…”

Elastomer solvent interactions III‐effects of methanol mixtures on fluorocarbon elastomers

“…This strongly suggests that there is restricted exchange of functional groups between the methanol and butanol hydrogen-bonded systems, probably because the butanol tetramer is energetically more stable. 22,23 The methanol/ethanol system was an ideal one in that both the methanol and ethanol existed as cyclic tetramers in the neat state and in mixtures. The exchange rates of the hydroxyl protons of both species were measured as equal over the entire x value range.…”