Frequency Dependent Kinetics of
the CW CO2 Laser Induced
Reaction of CF3CF2Cl

R. N. Zitter; D. F. Koster; N. Siddiqua

doi:10.1155/lc.7.271

Frequency Dependent Kinetics of the CW CO2 Laser Induced Reaction of CF3CF2Cl

Laser Chemistry ◽

10.1155/lc.7.271 ◽

1987 ◽

Vol 7 (5-6) ◽

pp. 271-277

Author(s):

R. N. Zitter ◽

D. F. Koster ◽

N. Siddiqua

Keyword(s):

Activation Energy ◽

Absorption Band ◽

Co2 Laser ◽

Laser Frequency ◽

Kcal Mole ◽

Band Center ◽

Laser Frequencies ◽

Cw Co2 Laser ◽

Kinetics Of ◽

Induced Reaction

Kinetics of the decomposition of CF3CF2Cl at 50 torr by a cw CO2 laser have been studied over a range of laser frequencies extending 36 cm−1 below an absorption band center at 980 cm−1. At constant translational temperature, the change in the rate constant with laser frequency is a factor of 100, comparable to the effect previously observed in CF2ClCF2Cl. Arrhenius plots show an activation energy of 86.2 kcal/mole, independent of frequency.

Laser frequency dependent kinetics of the cw CO2 laser induced reaction of CF2HCl and theory of the laser frequency effect

Optics Communications ◽

10.1016/0030-4018(87)90334-8 ◽

1987 ◽

Vol 63 (6) ◽

pp. 409-412 ◽

Cited By ~ 1

Author(s):

R.N. Zitter ◽

D.F. Koster ◽

H.K. Yun

Keyword(s):

Co2 Laser ◽

Laser Frequency ◽

Frequency Effect ◽

Frequency Dependent ◽

Cw Co2 Laser ◽

Kinetics Of ◽

Induced Reaction

Frequency dependent kinetics of the cw CO2 laser induced reaction of CF3Br

Optics Communications ◽

10.1016/0030-4018(86)90247-6 ◽

1986 ◽

Vol 59 (4) ◽

pp. 259-262 ◽

Cited By ~ 2

Author(s):

R.N. Zitter ◽

D.F. Koster ◽

M.S. Parvez

Keyword(s):

Co2 Laser ◽

Frequency Dependent ◽

Cw Co2 Laser ◽

Kinetics Of ◽

Induced Reaction

Vulcanization of Elastomers. 23. The Chemical Kinetics of Vulcanization Reactions and The Physical Properties of The Vulcanizates. I

Rubber Chemistry and Technology ◽

10.5254/1.3542149 ◽

1960 ◽

Vol 33 (2) ◽

pp. 335-341

Author(s):

Walter Scheele ◽

Karl-Heinz Hillmer

Keyword(s):

Activation Energy ◽

Physical Properties ◽

Chemical Kinetics ◽

Kcal Mole ◽

First Order ◽

Equilibrium Swelling ◽

Kinetics Of ◽

Kinetics Of Vulcanization ◽

Limiting Value ◽

Good Agreement

Abstract As a complement to earlier investigations, and in order to examine more closely the connection between the chemical kinetics and the changes with vulcanization time of the physical properties in the case of vulcanization reactions, we used thiuram vulcanizations as an example, and concerned ourselves with the dependence of stress values (moduli) at different degrees of elongation and different vulcanization temperatures. We found: 1. Stress values attain a limiting value, dependent on the degree of elongation, but independent of the vulcanization temperature at constant elongation. 2. The rise in stress values with the vulcanization time is characterized by an initial delay, which, however, is practically nonexistent at higher temperatures. 3. The kinetics of the increase in stress values with vulcanization time are both qualitatively and quantitatively in accord with the dependence of the reciprocal equilibrium swelling on the vulcanization time; both processes, after a retardation, go according to the first order law and at the same rate. 4. From the temperature dependence of the rate constants of reciprocal equilibrium swelling, as well as of the increase in stress, an activation energy of 22 kcal/mole can be calculated, in good agreement with the activation energy of dithiocarbamate formation in thiuram vulcanizations.

Insect blood-brain barrier: a radioisotope study of the kinetics of exchange of a liposoluble molecule (n-butanol)

Journal of Experimental Biology ◽

10.1242/jeb.64.1.119 ◽

1976 ◽

Vol 64 (1) ◽

pp. 119-130

Author(s):

M. V. Thomas

Keyword(s):

Activation Energy ◽

Temperature Sensitivity ◽

Nerve Cord ◽

Previous Investigation ◽

Time Course ◽

Kcal Mole ◽

Similar Time ◽

Kinetics Of ◽

Butanol Concentration ◽

Good Agreement

About 90% of the butanol uptake by the cockroach abdominal nerve cord washed out with half-times of a few seconds, in good agreement with an electrophysiological estimate, and the temperature sensitivity suggested an activation energy of 3 Kcal mole-1. The remaining activity washed out far more slowly, with a similar time course to that observed in a previous investigation which had not detected the fast fraction. Its size was similar to the non-volatile uptake, and was considerably affected by the butanol concentration and incubation period. It apparently consisted of butanol metabolites, which could be detected by chromatography.

Kinetics of the addition of acids to olefins with and without boron fluoride catalysis

Canadian Journal of Chemistry ◽

10.1139/v67-003 ◽

1967 ◽

Vol 45 (1) ◽

pp. 11-16 ◽

Cited By ~ 7

Author(s):

G. A. Latrèmouille ◽

A. M. Eastham

Keyword(s):

Activation Energy ◽

Acetic Acid ◽

Apparent Activation Energy ◽

Trifluoroacetic Acid ◽

Similar Rate ◽

Ethylene Dichloride ◽

Kcal Mole ◽

Rate Law ◽

Boron Fluoride ◽

Kinetics Of

Isobutene reacts readily with excess trifluoroacetic acid in ethylene dichloride solution at ordinary temperatures to give t-butyl trifluoroacetate. The rate of the reaction is given, within the range of the experiments, by the expression d[ester]/dt = k[acid]2[olefin], and the apparent activation energy is about 6 kcal/mole. The rate of addition is markedly dependent on the strength of the reacting acid and is drastically reduced in the presence of mildly basic materials, such as dioxane. The boron fluoride catalyzed addition of acetic acid to 2-butene can be considered to follow a similar rate law, i.e. d[ester]/dt = k[acid·BF3]2[olefin], but only if some assumptions are made about the position of the equilibrium [Formula: see text]since only the 1:1 complex is reactive.

Chemical Vapor Deposition of SiO2 from Ozone-Organosilane Mixtures near Atmospheric Pressure

MRS Proceedings ◽

10.1557/proc-282-575 ◽

1992 ◽

Vol 282 ◽

Cited By ~ 2

Author(s):

K. V. Guinn ◽

J. A. Mucha

Keyword(s):

Activation Energy ◽

Chemical Vapor Deposition ◽

Vapor Deposition ◽

Atmospheric Pressure ◽

Chemical Vapor ◽

Zero Order ◽

Kcal Mole ◽

Consumption Ratio ◽

Zero Order Kinetics ◽

Kinetics Of

ABSTRACTThe kinetics of deposition of SiO2 by the reaction of tetramethylsilane (TMS) with ozone (O3) has been studied over the temperature range 180 – 380° C and compared with available data for the same process using tetraethoxysilane (TEOS). Both processes exhibit the same activation energy (17 kcal/mole) below 300 ° C which falls-off at higher temperatures due to transport limitations. Transition from first- to zero-order kinetics occurs with increasing concentrations of TMS and O3, which gives an overall O3/TMS consumption ratio of 10 at 258° C and5 at 325° C. TEOS is estimated to be 5 times more reactive than TMS above 300° C and over 10 times more reactive in the kinetically-limited regime below 300° C. Results suggest that O3-induced SiO2 deposition proceeds via surface reactions and is limited by heterogeneous decomposition of ozone.

Vulcanization of Elastomers. 40. Vulcanization of Natural Rubber and Synthetic Rubber with Sulfur in Presence of Sulfenamides. III

Rubber Chemistry and Technology ◽

10.5254/1.3535627 ◽

1965 ◽

Vol 38 (1) ◽

pp. 189-203 ◽

Cited By ~ 4

Author(s):

W. Scheele ◽

J. Helberg

Keyword(s):

Activation Energy ◽

Reaction Mechanism ◽

Natural Rubber ◽

Rate Constants ◽

Sulfur Concentration ◽

Kcal Mole ◽

Synthetic Rubber ◽

Chemical Constitution ◽

Induction Times ◽

Kinetics Of

Abstract Vulcanization of natural rubber with sulfur was studied in presence of six sulfenamides, to determine the effect of the chemical constitution of the sulfenamide on sulfur decrease and on crosslinking. The results can be condensed as follows: (1) The kinetics of sulfur disappearance is in every respect qualitatively independent of the chemical constitution of the sulfenamide. (2) For the sulfenamides investigated, the smallest and largest rate constants for sulfur decrease differed only by a factor of two. (3) Greater differences are encountered in the induction times for sulfur decrease and for crosslinking. The latter are notably longer than those for sulfur disappearance. (4) The same activation energy, 23 kcal/mole, is derived from the temperature dependence of the induction times for all the sulfenamides. (5) The dissociation of sulfenamides in solution and their reaction with mercaptobenzothiazole were investigated further. The results provide the basis for a proposed reaction mechanism, which is presented in detail and can account for a number of the features typical of sulfenamide-accelerated vulcanization. (6) The drop in sulfur concentration goes at practically the same rate, if one introduces, instead of N, N-dicyclohexyl-2-benzothiazolesulfenamide, the corresponding ammonium mercaptide in equimolar concentration.

Spreading Kinetics of Molten 60Sn40Pb on Higher Melting Temperature Pb-Sn Alloy Substrates

MRS Proceedings ◽

10.1557/proc-390-189 ◽

1995 ◽

Vol 390 ◽

Author(s):

H. Conrad ◽

Z. Guo ◽

D. Y. Jung

Keyword(s):

Activation Energy ◽

Contact Angle ◽

Melting Point ◽

Kcal Mole ◽

Depth Of Penetration ◽

Spherical Cap ◽

Solid Diffusion ◽

Time Exponent ◽

Image Position ◽

Kinetics Of

ABSTRACTThe spreading of molten 60Sn40Pb drops on higher melting point Pb-Sn alloy substrates (3 to 10 wt.% Sn) was investigated for reflow temperatures of 205° to 300°C. Following melting the drop assumed the form of a slightly flared, spherical cap with some penetration into the substrate beneath the contact area. The effects of time and temperature on the contact angle θ and the depth of penetration h were of the formwhere the apparent activation energy Q was 4.2 kcal/mole for θ and 16 kcal/mole for h. The time exponent m (negative for θ and positive for h) decreased with temperature from ∼ 0.2–0.3 at 205°C to ∼0.05 at 260° and then increased again at higher temperatures. The magnitude of Q for θ is in accord with that for the viscosity of molten Pb-Sn alloys and that for h with a combined liquid-solid diffusion involved in the dissolution. Further work is however needed to identify unequivocally the mechanisms which govern the wetting in these duplex Pb-Sn alloy systems.

Kinetics of photosensitized chain reaction of 1,2-dichloroethane induced by a cw CO2 laser

Spectrochimica Acta Part A Molecular Spectroscopy ◽

10.1016/0584-8539(90)80173-v ◽

1990 ◽

Vol 46 (4) ◽

pp. 577-580

Author(s):

Ma Peihua ◽

Liu Julin ◽

Chen Guancheng

Keyword(s):

Co2 Laser ◽

Chain Reaction ◽

Cw Co2 Laser ◽

Kinetics Of

CW-CO2 laser-induced and SF6-sensitized decomposition of trifluoroacetic acid

Collection of Czechoslovak Chemical Communications ◽

10.1135/cccc19812854 ◽

1981 ◽

Vol 46 (11) ◽

pp. 2854-2859 ◽

Cited By ~ 13

Author(s):

Josef Pola

Keyword(s):

Trifluoroacetic Acid ◽

Surface Reaction ◽

Reaction Scheme ◽

Conventional Heating ◽

Reaction Products ◽

First Order ◽

Cw Co2 Laser ◽

Kinetics Of ◽

Induced Reaction ◽

Carbonyl Fluoride

CW-CO2 laser-induced and SF6-sensitized decomposition of trifluoroacetic acid affords reaction products different from those yielded by a conventional heating and offers a new way for decomposition of this compound. The kinetics of the laser-induced reaction is also different, being of a second order and of a first order in SF6. The reaction scheme proposed for the laser-induced process shows .CF2CO2. biradical to be mainly decomposed to carbon monoxide and carbonyl fluoride and implies that the fate of this species during conventional thermal decomposition is controlled by heterogeneous surface reaction.