Chlorination of Natural Rubber Solutions by Means of Phenyl Iododichloride

1955 ◽  
Vol 28 (2) ◽  
pp. 598-605 ◽  
Author(s):  
C. S. Ramakrishnan ◽  
D. Raghunath ◽  
J. B. Pande
Keyword(s):  
Thermal Decomposition ◽  
Carbon Tetrachloride ◽  
Natural Rubber ◽  
Hydrogen Chloride ◽  
Atmospheric Oxygen ◽  
A Value ◽  
Reaction Proceeds ◽  
Chlorine Radicals ◽  
Slight Amount ◽  
Additive Reaction

Abstract The loss of unsaturation attending the chlorination of carbon tetrachloride solutions of unmasticated pale crepe and deproteinized rubbers by means of phenyl iododichloride was followed by quantitative ozonization of the chlorinated products, ranging in chlorine contents from 2.3 to 73.6 per cent. It is concluded from such studies that the reaction proceeds mainly by the additive reaction of the chlorine radicals produced by the thermal decomposition of phenyl iododichloride. The hydrogen chloride found in the preparation of these chlorinated products was determined. It has a value below 1 per cent up to about 15 per cent chlorine content and thereafter it increases. However, this value generally does not exceed 4 per cent. This indicates the occurrence of only a slight amount of substitutive reaction by chlorine. Cyclization also takes place, probably following an additive reaction of the chlorine radicals. The main difference between the deproteinized rubber and pale crepe rubber reactions is confined to the very early stages, wherein the nonrubber components have a directive influence in bringing about a slightly earlier onset of cyclization. It is also concluded that atmospheric oxygen has a negligible effect on the reaction.

Observations of the Thermal Decomposition of Brucite

1968 ◽  
Vol 26 ◽  
pp. 446-447
Author(s):  
P. L. Burnett ◽  
W. R. Mitchell ◽  
C. L. Houck
Keyword(s):  
Thermal Decomposition ◽  
Magnesium Oxide ◽  
Basal Plane ◽  
Magnesium Ions ◽  
A Value ◽  
Reaction Proceeds

Natural Brucite (Mg(OH)2) decomposes on heating to form magnesium oxide (MgO) having its cubic ﹛110﹜ and ﹛111﹜ planes respectively parallel to the prism and basal planes of the hexagonal brucite lattice. Although the crystal-lographic relation between the parent brucite crystal and the resulting mag-nesium oxide crystallites is well known, the exact mechanism by which the reaction proceeds is still a matter of controversy. Goodman described the decomposition as an initial shrinkage in the brucite basal plane allowing magnesium ions to shift their original sites to the required magnesium oxide positions followed by a collapse of the planes along the original <0001> direction of the brucite crystal. He noted that the (110) diffraction spots of brucite immediately shifted to the positions required for the (220) reflections of magnesium oxide. Gordon observed separate diffraction spots for the (110) brucite and (220) magnesium oxide planes. The positions of the (110) and (100) brucite never changed but only diminished in intensity while the (220) planes of magnesium shifted from a value larger than the listed ASTM d spacing to the predicted value as the decomposition progressed.

A synthesis and some reactions of 7-Oxabicyclo[2.2.1]heptan-2-one

1983 ◽  
Vol 36 (12) ◽  
pp. 2473 ◽  
Author(s):  
J Moursounidis ◽  
D Wege
Keyword(s):  
Thermal Decomposition ◽  
Alder Reaction ◽  
Diels Alder ◽  
Acid Mixture ◽  
Diels Alder Reaction ◽  
Reaction Proceeds ◽  
Atom Migration ◽  
Acyl Azide ◽  
Mild Hydrolysis ◽  
Hydrolysis Of

Diels-Alder reaction between furan and α-chloroacrylonitrile gives a mixture of exo-2-chloro-and endo-2-chloro-7-oxabicyclo[2.2.1]hept-5-ene-2-carbonitrile (4) and (5). Mild hydrolysis affords the corresponding α-chloro acid mixture, from which the endo carboxylic acid may be removed through iodo lactone formation. Catalytic hydrogenation of (4) and (5) followed by hydrolysis, acyl azide formation, Curtius rearrangement, and hydrolysis of the resulting mixture of a-chloro isocyanates yields 7-oxabicyclo[2.2.l]heptan-2-one (1) in preparatively useful amounts. Reduction of (1) gives only endo alcohol, and Baeyer-Villiger reaction proceeds with exclusive bridgehead atom migration. Thermal decomposition of the sodium salt of the p-toluenesulfonylhydrazone of (1) affords 7-oxatricyclo[2.2.1 .02,6]heptane.

Chlorination of Natural Rubber in Solution with Gaseous Chlorine

1953 ◽  
Vol 26 (4) ◽  
pp. 902-911 ◽  
Author(s):  
C. S. Ramakrishnan ◽  
D. Raghunath ◽  
J. B. Pande
Keyword(s):  
Double Bond ◽  
Natural Rubber ◽  
Cyclization Reaction ◽  
Double Bonds ◽  
Chlorine Atoms ◽  
Reaction Stage ◽  
Stage 1 ◽  
Additive Reaction

Abstract The chlorination of rubber solutions by gaseous chlorine was followed by isolating the partially chlorinated products and preparing their ozonides. The ozonides were hydrolyzed, and the acids and aldehydes formed on hydrolysis were determined. By a comparison with the amounts of acids and aldehydes obtained from ozonides of unreacted rubber, the amount of residual isoprenic double bonds present was found. The loss of double bonds attending the introduction of chlorine atoms into the molecule of rubber indicates four definite stages in chlorination : (1) initial substitutive attack by chlorine, with concomitant cyclization, resulting in a loss of one double bond between two isoprenic units, (2) substitution, (3) additive reaction, and (4) essentially substitution. Chlorination of aged rubber solutions differs from the above in that the cyclization reaction (stage 1) seems to be absent.

scholarly journals The thermal decomposition of nitrogen pentoxide at low pressures

1925 ◽  
Vol 109 (751) ◽  
pp. 526-540 ◽  
Keyword(s):  
Thermal Decomposition ◽  
The Other ◽  
Nitrogen Tetroxide ◽  
Nitrogen Pentoxide ◽  
Other Hand ◽  
Rate Of Reaction ◽  
Reaction Proceeds ◽  
Products Of Reaction ◽  
Glass Surfaces ◽  
Low Pressures

Unimolecular reactions possess a unique interest in that, as Perrin (‘Ann. Physique,’ vol. 11, p. 5, 1919) first pointed out, for the occurrence of such, some type of interaction between radiation and matter must take place. Although such reactions appear to be extremely rare, many physical processes such as evaporation, ionisation in gases at high temperatures and radio-active decay, proceed at rates conforming to a unimolecular law; true chemical reactions which are definitely unimolecular and not pseudo-unimolecular in character are, on the other hand, stated by many ( e. g ., Lowry, ‘Trans. Farad. Soc.,’ vol. 17, p. 596 (1922) ) to be non-existent. In order to substantiate this statement, it is clearly necessary to prove the more complex character of any reaction which satisfies the usual criteria of unimolecular change. The thermal decomposition of gaseous nitrogen pentoxide apparently fulfils these conditions, for Daniels and Johnston (‘J. Am. C. S.,’ vol. 43, p. 53 (1921)) showed that the reaction proceeded according to a unimolecular law over wide ranges of variation of pressure, and Lueck ( ibid ., vol. 44, p. 757 (1922)) obtained practically identical unimolecular constants for the decomposition in solution in carbon tetrachloride and chloroform. On the other hand, Daniels, Wulf and Karrer ( ibid ., vol. 44, p. 2402 (1922) ) suspected the reaction to be autocatalytic, owing to the apparent retardation of the reaction velocity in the presence of ozone, but the experiments of one of us (Hirst, ‘J. C. S.,’ vol. 127, p. 657 (1925), and of White and Tolman (‘J. Am. C. S.’ vol. 47, p. 1,240 (1925)) proved this to be erroneous. In addition, it has been shown that the reaction proceeds uniformly according to the unimolecular law even in the presence of extensive glass surfaces, or of gases which may be either indifferent, such as argon and nitrogen, or the products of reaction, such as nitrogen tetroxide or dioxide or oxygen. The rate of reaction may be expressed in the form - d C/ dt = 4·98 × 10 13 e -24.700/RT . C. Attempts have been made to interpret the experimental results on the hypothesis that the reaction is in reality bimolecular, and only apparently unimolecular in character; but owing to the abnormally large value of the energy of activation, namely, 24,700 calories per gram. molecule, the number of molecules which could be activated per second by inelastic collision, calculated according to the kinetic theory, falls far short of the observed reaction rate, being, in fact, some 10 5 times smaller.

Thermal Decomposition of Carbon Tetrachloride Vapors at Its Industrial Threshold Limit Concentration

AIHAJ ◽  
1973 ◽  
Vol 34 (1) ◽  
pp. 25-37 ◽  
Author(s):  
MADBULI H. NOWEIR ◽  
EMIL A. PFITZER ◽  
THEODORE F. HATCH
Keyword(s):  
Thermal Decomposition ◽  
Carbon Tetrachloride ◽  
Threshold Limit

Formation of Carbon Layers by the Thermal Decomposition of Carbon Tetrachloride in a Reactor for MOCVD Epitaxy

2020 ◽  
Vol 54 (8) ◽  
pp. 956-960
Author(s):  
B. N. Zvonkov ◽  
O. V. Vikhrova ◽  
Yu. A. Danilov ◽  
M. V. Dorokhin ◽  
P. B. Demina ◽  
...  
Keyword(s):  
Thermal Decomposition ◽  
Carbon Tetrachloride

THE CONCENTRATED SOLUTION VISCOSITY OF GR-S: ITS VARIATION (IN BENZENE) WITH TEMPERATURE AND CONCENTRATION

1948 ◽  
Vol 26b (8) ◽  
pp. 551-563 ◽  
Author(s):  
L. H. Cragg ◽  
L. M. Faichney ◽  
H. F. Olds
Keyword(s):  
Natural Rubber ◽  
Energy Of Activation ◽  
Solution Viscosity ◽  
A Value ◽  
Concentrated Solution

With a falling ball viscometer, measurements of the viscosity of solutions of GR–S in benzene have been made at very low rates of shear, at concentrations ranging from 10 to 19%, and at temperatures ranging from 10° to 35 °C. Within these limits, the viscosity of a solution of GR–S in benzene is given by the equation [Formula: see text]. Extrapolation, by means of this equation, to 100% polymer yields a value of 13.0 kcal. per mole for the energy of activation of flow of GR–S; this value, though of dubious antecedence, is yet of interest because it approximates that expected for GR–S on the basis of the behavior of such polymers as natural rubber and polystyrene.

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