SELF-ASSOCIATION OF CIS-9-OCTADECEN-1-OL IN THE PURE LIQUID-STATE ANDIN DECANE SOLUTIONS AS OBSERVED BY VISCOSITY, SELF-DIFFUSION, NUCLEAR-MAGNETIC-RESONANCE, ELECTRON-SPIN-RESONANCE, AND NEAR-INFRARED SPECTROSCOPIC MEASUREMENTS

The self-association of cis-9-octadecen-1-ol in the pure liquid state and in decane solutions has been studied mainly through near-infrared spectroscopic observation over the temperature range 298.1-348.1 K. Th e analysis of the sharp band at 1410 nm (the first overtone band of OH -stretching vibration mode attributed to free OH-monomer and partly to OH-polymer) leads to a conclusion that the apparent degree of associa tion, n, of the polymer of cis-9-octadecen-1-ol is 2.37-3.78 (average 2.95) both in the pure liquid state and in decane solutions; the n val ue has a tendency to decrease with an increase in temperature. The app arent association constant, K, which is relatively low, also decreases with an increase in temperature. The low K value, which means small p ortions of polymerized molecules, is most Likely responsible for the h igh selfdiffusion and the low viscosity of cis-9-octadecen-1-ol, compa red with those of cis-9-octadecenoic acid, existing almost entirely as cyclic dimers.