Self-association of octan-1-ol in the pure liquid state and in decane solutions as observed by viscosity, self-diffusion, nuclear magnetic resonance and near-infrared spectroscopy measurements

Abstract

The self-association of octan-1-01 in the pure liquid state and in decane solutions has been studied by nearinfrared spectroscopic observation over the temperature range 298.1-348.1 K and also by viscosity, self-diff usion and NMR measurements. The absorption bands assigned to the hydroxy group are superimposed on several bands attributed to the methylene groups belonging to both the alcohol and decane molecules. A superior technique using a computer was adopted for the cancellation of the absorption bands due to the methylene groups so as to obtain the net OH absorption bands. The analysis of the sharp band at 1410 nm (the first overtone band of the OH-stretching vibration attributed to the free OH-monomer and partly to the OH-polymer) leads to the conclusion that the mean degree of association n (i.e. the average size of the multimer in monomeric units) in the polymer of octan-1-01 is ca. four, both in the liquid and in decane solutions under the temperature conditions given above. From the arguments about the aggregated species, a cyclic tetramer was proposed as the associated alcohol species in the liquid and in decane solutions. The association equilibrium constant and other thermodynamic properties such as changes in enthalpy, entropy and Gibbs energy for tetramer formation were also determined.

Aggregate formation in oil and adsorption at oil/water interface: thermodynamics and its application to the oleyl alcohol system

“…Provided the distribution of the aggregation number is small, N 2 /N is practically equal to N . Figure 7 shows that the values N 2 /N is close to the aggregation number expected for alcohols in nonpolar solvents [4,7,8], although it is not a constant value and is a little larger than the expected one.…”

“…Now the total differential dm r is written as a function of T , p, and m by using Eqs. (4) and (16), and then dm a = r=2 dm r is also written as…”

“…The properties of oil solutions of long-chain alcohols have been studied from the different points of views and it has been known that alcohol molecules gather together to form aggregates in oil solutions [1][2][3][4][5][6][7][8][9][10]. Also, in our previous paper [11], the enthalpy of mixing of oleyl alcohol and oils was measured by a high-accuracy isothermal calorimeter and the aggregation behavior of the alcohol molecules has been elucidated.…”

Debye relaxation and 250 K anomaly in glass forming monohydroxy alcohols

“…It has been found that rings composed of about 4 or more members contribute to A(λ δ ) (Ref. 56) and then would tend to increase the calculated 〈n〉.…”

Use of Principal Component Analysis in a near Infrared Study of the Dissociation Process of Oleyl Alcohol

“…[1][2][3][4][5][6][7][8] However, until recently, [9][10][11][12][13][14][15][16][17][18][19][20] the NIR investigations were not always satisfactory in the quantitative aspect; there was no reliable method for determining precisely the intensities of key bands such as the first overtones of OH and NH stretching modes. Recent rapid progress both in hardware and software for NIR spectroscopy has brought about innovative changes in the NIR studies of self-associated compounds.…”