Volume 9, Issue 12, 01 December 1941
Index of content:
9(1941); http://dx.doi.org/10.1063/1.1750853View Description Hide Description
An investigation has been made of the mercury (3 P 1) photosensitized reactions of ethylene. In addition to hydrogen and acetylene the main products are butene, butane and hexenes. The variation of the rate with the pressure of ethylene suggests that a deactivation process is involved, the initial process being of the typefollowed byorPolymerization arises largely by a free radical mechanism and butane is formed by the reactionsThe mechanism is shown to be consistent with the value found for the quantum yield.
Further Studies on the Oxidation of Nitric Oxide; the Rate of the Reaction between Carbon Monoxide and Nitrogen Dioxide9(1941); http://dx.doi.org/10.1063/1.1750854View Description Hide Description
The initial rate of the reaction between CO and NO2 from 225°C to 290°C was measured under conditions which precluded the possibility of NO2 decomposition. This study extends the earlier data on the reaction over a 300° temperature interval. The oxidation of nitric oxide at 25°C and at pressures from 0.01 to 0.1 mm of NO was found to be third order over a 3‐ and 6‐fold change in reactants. The CO2 and NO2 production in systems containing NO, CO, and O2 around 150°C was measured under conditions in which the formation of CO2 by the reaction between CO and NO2 was negligible. It is concluded that NO3 is the intermediate needed to correlate this and previous data on reactions involving NO and NO2, and that the rate of the reaction of NO3 with NO is faster than that with CO.
A new apparatus containing greaseless valves capable of handling quantities of products of the order of 10—3 mm, and a method of analysis precise to 3×10—5 mm was devised. Methods to prepare reactant gases of the requisite purity are described.
9(1941); http://dx.doi.org/10.1063/1.1750855View Description Hide Description
Complete expressions for the rotation‐vibration energies of the linear Y2X2 molecules, through second order of approximation, have been obtained in the form E = hc(GV+FR). The vibrational term GV obtained agrees exactly with that found by Wu and Kiang, but there are numerous points of difference in the rotational term FR.
The Region of Critical Solution of Binary Liquids, Evidence for an Anomalous First‐Order Transition in the System Triethyl Amine‐Water9(1941); http://dx.doi.org/10.1063/1.1750856View Description Hide Description
The change of fugacity with composition has been investigated in the liquid system triethyl amine‐water in the temperature region adjacent to the temperature of critical solution. It has been shown that within experimental error this change is zero for a range of at least 5°C on the one phase side, and for compositions of liquid between 20 and 50 weight percent. This is taken to be evidence for the existence of a range of anomalous first‐order transition adjacent to the critical temperature. Values of change of fugacity with composition have been determined sufficiently precisely to be in definite disagreement with simple conclusions drawn from the concept of the continuity of states.
9(1941); http://dx.doi.org/10.1063/1.1750857View Description Hide Description
From third law measurements,vapor pressures and vapor densities, the entropy of the acetic acidmonomer at 25° and one atmosphere is 69.4±1.0 e.u. The value 68.7 is calculated from the vapor phase ethyl acetate equilibrium. For a model based upon acetone and approximately representing free rotation the entropy would be 72.7. If there is only a single potential minimum in the hydroxyl group rotational cycle, the large deficiency below the free rotation value is explained without assuming an exceptionally high potential barrier. A brief discussion of the effect of the number of potential minima and their relative depth is appended, and a possible source of error in third law measurements is suggested.
9(1941); http://dx.doi.org/10.1063/1.1750858View Description Hide Description
An empirical equation used by Keyes to represent the second virial coefficients of several polar gases is compared to a theoretical expression for the same quantity. The constants appearing in this equation are discussed in terms of intermolecular forces, and their relationship to analogous constants in the Beattie‐Bridgeman equation for non‐polar gases is examined. These considerations permit the construction of simple rules by means of which the second virial coefficient of any gas mixture may be calculated if the second virial coefficients and dipole moments of the pure component gases are known. The success of these rules is demonstrated by comparison with data on H2O–CO2, N2–NH3, and N2–H2O systems. In the case of N2–H2O mixtures (vapor‐liquid equilibrium data) the agreement is not satisfactory at the higher temperatures. A rough method of including the effect of higher virial coefficients reduces, but does not remove, this discrepancy.
The Compressibilities of Gaseous Mixtures of Methane and Normal Butane. The Equation of State for Gas Mixtures9(1941); http://dx.doi.org/10.1063/1.1750859View Description Hide Description
The compressibilities of three gaseous mixtures of methane and normal butane have been measured from 100° to 300°C and from 1.25 to 10 mole/liter (maximum pressure 350 atmos.). The data on these three systems and the two pure hydrocarbons are used to study several methods of combination of constants in the Beattie‐Bridgeman equation of state extended to apply to gas mixtures. The best results were obtained with square‐root combination for A 0 and for c and Lorentz combination for B 0; but square root combination for A 0 and linear combination for B 0 and for c are a fair compromise between accuracy of representation of the data on mixtures and simplicity of expression.
9(1941); http://dx.doi.org/10.1063/1.1750860View Description Hide Description
By x‐ray diffraction, the chemical formula and crystal structure of Pt3O4 have been established. The crystal lattice has a body‐centered cube symmetry. The edges of the cubes are 6.226A long, and there are two molecules per unit cell. A chemical method for preparing this oxide has been given by Jörgensen but Wöhler claims that the compound thus obtained is a mixture of monoxide and dioxide rather than a separate chemical entity, see references 2 and 3.
9(1941); http://dx.doi.org/10.1063/1.1750861View Description Hide Description
- LETTERS TO THE EDITOR