THE PHOTOCHEMICAL FORMATION OF CHLORINE DIOXIDE FROM CHLORINE MONOXIDE IN CARBON TETRACHLORIDE SOLUTION

1930 ◽  
Vol 52 (11) ◽  
pp. 4288-4297 ◽  
Author(s):  
Roscoe G. Dickinson ◽  
Cecil E. P. Jeffreys
Keyword(s):  
Carbon Tetrachloride ◽  
Chlorine Dioxide ◽  
Carbon Tetrachloride Solution ◽  
Photochemical Formation ◽  
Chlorine Monoxide

THE PHOTODECOMPOSITION OF CHLORINE DIOXIDE IN CARBON TETRACHLORIDE SOLUTION

1937 ◽  
Vol 15b (12) ◽  
pp. 499-524 ◽  
Author(s):  
J. W. T. Spinks ◽  
H. Taube
Keyword(s):  
Thermal Decomposition ◽  
Carbon Tetrachloride ◽  
Quantum Yield ◽  
Light Intensity ◽  
Quantum Efficiency ◽  
Chlorine Dioxide ◽  
Concentration Effects ◽  
Low Light ◽  
Carbon Tetrachloride Solution ◽  
Chlorine Monoxide

Insolation of carbon tetrachloride solutions of chlorine dioxide initiates a thermal decomposition, the magnitude of which may exceed that for the photoreaction with low light intensity. This thermal decomposition is inhibited by keeping the solutions at 3 °C. or by adding water.In contradiction to the findings of other investigators, it is found that chlorine and oxygen are not the only products of photodecomposition. As products of the photodecomposition of chlorine dioxide at the wave-lengths 3650 and 4360 Å, the oxides Cl2O, Cl2O6, and Cl2O7 as well as chlorine and oxygen appear. The quantum efficiency at λ 3650 Å is 2, and at 4360 Å, 1.In the unsensitized decomposition, concentration effects are observed which are greatly decreased when the solutions are stirred.In the bromine sensitized decomposition with 5460 Å, there is less chlorine monoxide but relatively as much Cl2O6 and Cl2O7 formed as in the unsensitized reaction.In the sensitized decomposition the quantum yield is independent of the concentration of chlorine dioxide, but depends on the light intensity. The observed quantum yield for the sensitized reaction is 0.2 to 0.3.Mechanisms for the photo-reactions have been proposed.

scholarly journals The kinetics of the decomposition, in carbon tetrachloride solution, of ozone and of ozone-chlorine mixtures

1931 ◽  
Vol 134 (823) ◽  
pp. 211-223 ◽  
Keyword(s):  
Carbon Tetrachloride ◽  
Catalytic Decomposition ◽  
Unimolecular Decomposition ◽  
Normal Medium ◽  
Gaseous State ◽  
Carbon Tetrachloride Solution ◽  
Nitrogen Pentoxide ◽  
Chlorine Monoxide ◽  
Uncertain Evidence ◽  
Direct Measurements

It was recently found that the decomposition of chlorine monoxide takes place at the same rate in solution in carbon tetrachloride as in the gaseous state. Under both conditions the reaction occurs in consecutive stages, each bimolecular. The rate of the unimolecular decomposition of nitrogen pentoxide is also uninfluenced by carbon tetrachloride. Thus this solvent appears to be established as a “normal” medium for reactions of varying kinetic type. The interest of this lies in the fact that with reactions that cannot be measured in the gaseous state at all, the rate in carbon tetrachloride can be taken as the rate which the reaction would have in the absence of a medium, and the influence of any given solvent can at once be recognised as accelerating or retarding. In this way it may be possible to obtain a deeper understanding of the effect of solvents on the rates of chemical reactions. In the meantime it is desirable to make as many direct measurements as possible on reactions which can be measured both in the gas and in solution. This paper deals with the decomposition of ozone, and with the catalytic decomposition of ozone by chlorine, both in carbon tetrachloride solution. The gaseous reactions have both been fairly extensively studied. The catalytic reaction takes place in the dark in a complex series of changes, and has even been said, though on somewhat uncertain evidence, to involve chains of 10 4 cycles; nevertheless, the rate in carbon tetrachloride solution is the same as the rate in the gas phase within a factor of 1·5 to 1. Further, in the corresponding photochemical reaction the number of molecules of ozone decomposed for each quantum of light is 2 both in the gas and in solution. Thus we have evidence that the several different chemical changes involved in these reactions are all almost unaffected by the carbon tetrachloride.

scholarly journals The kinetics of reactions in solution. Part I.—A comparison of the decomposition of chlorine monoxide in the gaseous state and in carbon tetrachloride solution

1931 ◽  
Vol 131 (816) ◽  
pp. 177-186 ◽  
Keyword(s):  
Carbon Tetrachloride ◽  
Gas Phase ◽  
Gaseous Phase ◽  
Bimolecular Reaction ◽  
Bimolecular Reactions ◽  
Unimolecular Reactions ◽  
Gaseous State ◽  
Carbon Tetrachloride Solution ◽  
Nitrogen Pentoxide ◽  
Chlorine Monoxide

In general the rate of a chemical reaction is profoundly influenced by the solvent in which the reaction takes place. In Menschutkin’s experiments on the combination of tertiary amines and alkyl halides, for example, the reaction velocity in benzyl alcohol was several hundred times greater than that in hexane. While it is clear that the influence of the solvent, which cannot be correlated definitely with any physical properties, belongs to the category of specific chemical effects, it is not easy to see in exactly what it consists. Christiansen and Norrish and Smith have found that the rate of a bimolecular reaction in solution appears usually to be several powers of 10 smaller than that of a hypothetical reaction occurring in the gaseous phase with the same energy of activation. Norrish and Smith therefore suggest that, since each encounter between molecules of the reacting substances takes place with a solvent molecule in very close proximity, and is thus virtually a ternary collision, the influence of the solvent is primarily a deactivating one. On the other hand, the decomposition of nitrogen pentoxide—a unimolecular reaction—takes place at the same rate and possesses the same heat of activation in chloroform, in carbon tetrachloride and a number of similar solvents as it does in the gaseous phase. In certain other solvents, quite different rates and heats of activation are found. Daniels regards as “normal” those solvents in which the reaction occurs at the same rate as in the gaseous phase, and attributes the deviations found with other, “abnormal,” solvents to a definite formation of complex molecules whose stability differ from that of free nitrogen pentoxide. The isomerisation of pinene has also been found to take place at the same rate in the gaseous and in the liquid states. As far as this not very abundant evidence goes, then, it would suggest that bimolecular reactions are usually much slower in solution than in the gaseous phase, while unimolecular reactions tend usually to be uninfluenced by the presence of the solvent. This simple contrast, however, is by no means correct. In the first place, the variation in the rates of unimolecular reactions with change of solvent appears on closer inspection to be not less marked than that of bimolecular reactions. This aspect of the matter is dealt with more fully in the following paper. In the second place, there have hitherto been no data available for comparing the rate of a bimolecular reaction in the gas phase with its rate in solution in one of the relatively inert solvents which had been used for nitrogen pentoxide. It is shown in the present paper, however, that the decomposition of chlorine monoxide, which is essentially bimolecular, although somewhat complex in mechanism, occurs at almost exactly the same rate in carbon tetrachloride as in the gaseous state, and that the heat of activation is substantially the same. Thus it appears that, contrary to first impressions, the kinetic type of the reaction has little to do with the influence of solvents. The chemical nature of the solvent is the determining factor in all cases. Both for bimolecular and unimolecular reactions there appear to exist “ideal” solvents, of which carbon tetrachloride is a good example. This is being confirmed by Mr. Bowen and the writers by measurements on the rate of decomposition of ozone in carbon tetrachloride solution. For reactions that cannot be made to take place in the gas phase at all, and this includes the majority of measurable reactions, the rate in carbon tetrachloride or an analogous solvent would then appear to be a standard or ideal rate equal to that which the gas reaction would possess. Comparison of the rate and the energy of activation of a given reaction in any solvent with the corresponding values for the reaction in carbon tetrachloride thus provides a means of ascertaining whether the solvent has increased or decreased the normal heat of activation, and whether its effect is to be regarded as deactivating or positively catalytic. The similarity of behaviour of chlorine monoxide in the gaseous phase and in carbon tetrachloride solution suggests that, for bimolecular as well as for unimolecular reactions, solvents must be divided into two classes, and that the deactivating influences postulated by Norrish and Smith are as specific as the influence of “abnormal” solvents on unimolecular reactions.

The Photo‐Chlorination of Methyl Chloroformate in Carbon Tetrachloride Solution

1949 ◽  
Vol 17 (6) ◽  
pp. 566-573 ◽  
Author(s):  
T. L. Batke ◽  
L. M. Dorfman ◽  
D. J. LeRoy
Keyword(s):  
Carbon Tetrachloride ◽  
Carbon Tetrachloride Solution

Synthesis of Silicon Carbide Films from Partially Oxidized Polyvinylsilane by Carbon Tetrachloride Solution Casting

2002 ◽  
Vol 17 (1) ◽  
pp. 214-223 ◽  
Author(s):  
Masaki Narisawa ◽  
Takeshi Hasegawa ◽  
Kiyohito Okamura ◽  
Masayoshi Itoh ◽  
Thomas Apple ◽  
...  
Keyword(s):  
Silicon Carbide ◽  
Carbon Tetrachloride ◽  
Radical Polymerization ◽  
Air Flow ◽  
Spectroscopic Studies ◽  
Flow Time ◽  
Silica Layer ◽  
Solution Casting ◽  
Amorphous Films ◽  
Carbon Tetrachloride Solution

Polyvinylsilane (PVS), derived from vinylsilane by radical polymerization, was partially oxidized in hot carbon tetrachloride solution by flowing air. If the air flow time is adjusted, soft gel films can be formed in a Teflon dish by casting the PVS solution. After the PVS films were peeled from the substrates, they were pyrolyzed at various temperatures. Spectroscopic studies of the pyrolyzed films up to 1273 K suggested that carbosilane (Si–CH2–Si) structures are formed in the films at 473–673 K. The compositions of the amorphous films obtained at 1673 K were approximately SiC1.38O0.21 and SiC1.41O0.51, depending on the crosslinking conditions. The oxygen incorporated in the films was removed in the form of CO and SiO during further heating at 1673–1873 K. The compositions of the films were changed to approximately SiC1.25 and SiC1.26, respectively, at 2073 K. The films obtained at 1273 K did not show degradation during the oxidation at 1273–1673 K while a protective silica layer was formed on their surfaces.

Sign in / Sign up

Export Citation Format

Share Document