The Influence of Surface Tension on the Measurement of Viscosity The Viscosity of Methanol

Abstract

The Viscosity of Methanol 1683 is an orthoquinone, there is no steric restriction on forming these bonds. In a paraquinone, however, the two bonds can be formed only by putting the planes of the two six-carbon rings flatly one upon the other. This will be easily possible in benzoquinone, but in duroquinone the voluminous side chains prevent a sufficiently close approach. It may be briefly and preliminarily mentioned that the ease with which a solid quinhydrone is formed by mixing a quinone with the corresponding hydroquinone, decreases with the number of CH3 groups which substitute the H atoms. In the tetramethyl compound, duroquinone, no quinhydrone is formed at all at room temperature.The authors are deeply indebted to Columbia University for the use of their facilities. SummaryDuroquinone in a strongly alkaline solution forms a free paramagnetic semiquinone radical of brown color as intermediate step of the reduction. There is no dimeric form of this radical; in other words, no compound corresponding to the ordinary crystalline benzoquinhydrone, which is a dimeric diamagnetic molecule, is formed from duroquinone and durohydroquinone either from alkaline or acid solutions. Solid benzoquinhydrone is a compound formed from quinone and hydroquinone by two hydrogen bonds. These bonds cannot be formed in duroquinone due to steric hindrance.The maximum percentage of the duro-semiquinone radical in equilibrium with its parent substances continuously increases with increasing pH. At pH 13 this maximum is about 50%, a result which is the same whether derived from potentiometric or magnetic observations. New York, N. Y.

Is a “Cloud-Point Curve” in Aqueous Poly(N-isopropylacrylamide) Solution Binodal?

“…The values of n 0 of water at λ 0 = 532 nm and at 15.0 and 20.0 °C are 1.3356 and 1.3350, respectively, which were evaluated from the above-mentioned n 0 value 1.3345 at 25.0 °C and d n 0 /d T = − 1.1 × 10 −4 deg −1 . We used the value 0.545 cP of the viscosity coefficient η 0 of methanol at 25.0 °C, and those 1.138, 1.002, and 0.890 cP of η 0 of water at 15.0, 20.0, and 25.0 °C, respectively…”

Ion Conductances in Water-Methanol Mixtures.

“…The specific conductance and density of the distillate were 1.1 X 10~7 mhos and 0.78657 g. per cubic centimeter at 25°C., respectively. Accepting 0.78653 (10) the density of pure methanol, our sample contained 0.024 mole per cent of water, which was taken into account in computing the mole fractions of the various mixtures prepared from this material. The densities of the solvents and solutions were measured to about 0.002 per cent in the pycnometer described in connection with our transference measurements in mixtures of light and heavy water (11).…”

Viscosities and densities of binary mixtures of 1-alkanols from 15 to 55.degree.C

“…The viscous heat and the preexponential factor of the mixtures were also calculated from the equation = 0 exp(EJRT) (8) where is viscosity, 0 is the preexponential factor, Ev is viscous heat, R is the gas constant, and T is the absolute temperature.…”