The Reaction of Hydroperoxides with Triphenylphosphine

1971 ◽  
Vol 49 (10) ◽  
pp. 1707-1711 ◽  
Author(s):  
R. Hiatt ◽  
R. J. Smythe ◽  
Christine McColeman
Keyword(s):  
Free Radical ◽  
Rate Equation ◽  
Additional Term ◽  
Second Order ◽  
The Other ◽  
Radical Mechanism ◽  
Tert Butyl ◽  
Organic Sulfides ◽  
Radical Traps

The reductions of n-butyl, sec-butyl, and tert-butyl hydroperoxides by triphenylphosphine in ethanol have been shown to follow second-order kinetics with k2's equal, respectively to 107.2e−8.4/RT, 109.0e−10.8/RT, 108.8e−11.2/RT. Similar results obtain in CH2Cl2, but in hexane the rate equation requires an additional term, k3[Ph3P][RO2H]2, though the overall reaction is somewhat faster than in the other solvents.Retardation, apparently by adventitious impurities, has been observed in some cases, but attempts to inhibit the reaction by free radical traps were unsuccessful. Parallels with reduction of hydroperoxides by organic sulfides suggest a similar non-radical mechanism.

The thermal decomposition of RDX at temperatures below the melting point. III. Towards the elucidation of the mechanism

1971 ◽  
Vol 24 (5) ◽  
pp. 945 ◽  
Author(s):  
JJ Batten
Keyword(s):  
Thermal Decomposition ◽  
Free Radical ◽  
Melting Point ◽  
Nitrogen Dioxide ◽  
The Other ◽  
Decomposition Products ◽  
Radical Traps

The rate of thermal decomposition of RDX has been investigated in the presence of its decomposition products and free radical traps. From the measurements, it is concluded that formaldehyde and nitrogen dioxide, presumably ?encaged? in the sample, catalyse the decomposition of RDX positively and negatively respectively. The non-volatile residue also acts as a positive catalyst. The other products have little or no effect on the rate, and the free radical traps did not reduce the rate.

The kinetics of the oxidation of ammonia by nitrous oxide

1964 ◽  
Vol 17 (2) ◽  
pp. 202 ◽  
Author(s):  
TN Bell ◽  
JW Hedger
Keyword(s):  
Thermal Decomposition ◽  
Nitrous Oxide ◽  
Free Radical ◽  
Rate Equation ◽  
Radical Mechanism ◽  
15N Isotope ◽  
Free Radical Mechanism ◽  
Products Of Reaction ◽  
Kinetics Of ◽  
Decomposition Of Nitrous Oxide

Ammonia is oxidized by nitrous oxide smoothly and homogeneously at temperatures between 658 and 730� and total pressures up to 250 mm. The products of reaction, nitrogen, water, and hydrazine are accounted for by a free-radical mechanism initiated by oxygen atoms which result from the thermal decomposition of nitrous oxide. Ammonia labelled with the 15N-isotope was used to distinguish between the nitrogen formed from the nitrous oxide and that from the ammonia. The kinetics follow an empirical rate equation, ������������� Rate = k'[N2O]1.56 + k"[N2O]0.61[NH3]. This is of a form which shows the importance of the ammonia molecule participating in the activation of nitrous oxide through bimolecular collision. Assigning a collisional efficiency of unity for like N2O-N2O collisions, the efficiency of ammonia in the process ������������ NH3 + N2O → NH3 + N2O* is determined as 0.85.

scholarly journals Polyoxometalates catalysts in the oxidation of cyclooctane by hydrogen peroxide

2012 ◽  
Vol 77 (11) ◽  
pp. 1599-1607 ◽  
Author(s):  
Wimonrat Trakarnpruk ◽  
Apiwat Wannatem ◽  
Jutatip Kongpeth
Keyword(s):  
Hydrogen Peroxide ◽  
Free Radical ◽  
Reaction Time ◽  
High Selectivity ◽  
Experimental Results ◽  
Molar Ratio ◽  
Radical Mechanism ◽  
Tetrabutylammonium Salt ◽  
Free Radical Mechanism ◽  
Radical Traps

A Keggin-type tungstocobaltate, [Co(2,2'- bipy)3]2H2[CoW12O40]?9.5H2O ([Co]CoW) and tetrabutylammonium salt of vanadium-substituted tungstophosphates [(n-C4H9)4N]4[PVW11O40], [(n-C4H9)4N]5[PV2W10O40] (PVW, PV2W) were used as catalyst for oxidation of cyclooctane with H2O2 as oxidant in acetonitrile. The activity of [(n-C4H9)4N4H[PCo(H2O)W11O39]?2H2O (PCoW) was also compared. The products of the reaction were cyclooctanone, cyclooctanol and cyclooctyl hydroperoxide. The experimental results showed that at H2O2/cyclooctane molar ratio = 3 at 80?C, in 9 h the [Co]CoW yielded higher conversion and selectivity to cyclooctanone. The V-based catalysts are more active than the Co-based tungstophosphate. The PV2W gave rise to high selectivity to cyclooctyl hydroperoxide. Cyclooctane conversion was increased by increasing reaction time or H2O2/cyclooctane molar ratio. In the presence of tungstocobaltate catalyst, 88% cyclooctane conversion and 82% selectivity of cyclooctanone were obtained after 12 h using H2O2/cyclooctane molar ratio of 9. This catalyst is stable upon treatment with H2O2. Experiments with radical traps suggest the involvement of a free-radical mechanism.

The Dark Tetrad

2015 ◽  
Vol 36 (4) ◽  
pp. 228-236 ◽  
Author(s):  
Janko Međedović ◽  
Boban Petrović
Keyword(s):  
Personality Traits ◽  
Antisocial Behavior ◽  
Second Order ◽  
The Other ◽  
Negative Pole ◽  
Latent Space ◽  
Order Factor

Abstract. Machiavellianism, narcissism, and psychopathy are personality traits understood to be dispositions toward amoral and antisocial behavior. Recent research has suggested that sadism should also be added to this set of traits. In the present study, we tested a hypothesis proposing that these four traits are expressions of one superordinate construct: The Dark Tetrad. Exploration of the latent space of four “dark” traits suggested that the singular second-order factor which represents the Dark Tetrad can be extracted. Analysis has shown that Dark Tetrad traits can be located in the space of basic personality traits, especially on the negative pole of the Honesty-Humility, Agreeableness, Conscientiousness, and Emotionality dimensions. We conclude that sadism behaves in a similar manner as the other dark traits, but it cannot be reduced to them. The results support the concept of “Dark Tetrad.”

scholarly journals New oscillation criteria for second-order neutral differential equations with distributed deviating arguments

2021 ◽  
Vol 2021 (1) ◽  
Author(s):  
Osama Moaaz ◽  
Choonkil Park ◽  
Elmetwally M. Elabbasy ◽  
Waed Muhsin
Keyword(s):  
Differential Equations ◽  
Second Order ◽  
The Other ◽  
Riccati Transformation ◽  
Transformation Technique ◽  
Deviating Arguments ◽  
Neutral Differential Equations ◽  
Second Order Differential Equations ◽  
Continuous Delay ◽  
New Criteria

AbstractIn this work, we create new oscillation conditions for solutions of second-order differential equations with continuous delay. The new criteria were created based on Riccati transformation technique and comparison principles. Furthermore, we obtain iterative criteria that can be applied even when the other criteria fail. The results obtained in this paper improve and extend the relevant previous results as illustrated by examples.

Neural computation of motion in the fly visual system: quadratic nonlinearity of responses induced by picrotoxin in the HS and CH cells

1995 ◽  
Vol 74 (6) ◽  
pp. 2665-2684 ◽  
Author(s):  
Y. Kondoh ◽  
Y. Hasegawa ◽  
J. Okuma ◽  
F. Takahashi
Keyword(s):  
Mean Square Error ◽  
Order Term ◽  
Mirror Image ◽  
Second Order ◽  
The Other ◽  
Linear Component ◽  
Mean Square ◽  
Nonlinear Component ◽  
First Order ◽  
Order Kernel

1. A computational model accounting for motion detection in the fly was examined by comparing responses in motion-sensitive horizontal system (HS) and centrifugal horizontal (CH) cells in the fly's lobula plate with a computer simulation implemented on a motion detector of the correlation type, the Reichardt detector. First-order (linear) and second-order (quadratic nonlinear) Wiener kernels from intracellularly recorded responses to moving patterns were computed by cross correlating with the time-dependent position of the stimulus, and were used to characterize response to motion in those cells. 2. When the fly was stimulated with moving vertical stripes with a spatial wavelength of 5-40 degrees, the HS and CH cells showed basically a biphasic first-order kernel, having an initial depolarization that was followed by hyperpolarization. The linear model matched well with the actual response, with a mean square error of 27% at best, indicating that the linear component comprises a major part of responses in these cells. The second-order nonlinearity was insignificant. When stimulated at a spatial wavelength of 2.5 degrees, the first-order kernel showed a significant decrease in amplitude, and was initially hyperpolarized; the second-order kernel was, on the other hand, well defined, having two hyperpolarizing valleys on the diagonal with two off-diagonal peaks. 3. The blockage of inhibitory interactions in the visual system by application of 10-4 M picrotoxin, however, evoked a nonlinear response that could be decomposed into the sum of the first-order (linear) and second-order (quadratic nonlinear) terms with a mean square error of 30-50%. The first-order term, comprising 10-20% of the picrotoxin-evoked response, is characterized by a differentiating first-order kernel. It thus codes the velocity of motion. The second-order term, comprising 30-40% of the response, is defined by a second-order kernel with two depolarizing peaks on the diagonal and two off-diagonal hyperpolarizing valleys, suggesting that the nonlinear component represents the power of motion. 4. Responses in the Reichardt detector, consisting of two mirror-image subunits with spatiotemporal low-pass filters followed by a multiplication stage, were computer simulated and then analyzed by the Wiener kernel method. The simulated responses were linearly related to the pattern velocity (with a mean square error of 13% for the linear model) and matched well with the observed responses in the HS and CH cells. After the multiplication stage, the linear component comprised 15-25% and the quadratic nonlinear component comprised 60-70% of the simulated response, which was similar to the picrotoxin-induced response in the HS cells. The quadratic nonlinear components were balanced between the right and left sides, and could be eliminated completely by their contralateral counterpart via a subtraction process. On the other hand, the linear component on one side was the mirror image of that on the other side, as expected from the kernel configurations. 5. These results suggest that responses to motion in the HS and CH cells depend on the multiplication process in which both the velocity and power components of motion are computed, and that a putative subtraction process selectively eliminates the nonlinear components but amplifies the linear component. The nonlinear component is directionally insensitive because of its quadratic non-linearity. Therefore the subtraction process allows the subsequent cells integrating motion (such as the HS cells) to tune the direction of motion more sharply.

PLATELET AGGREGATION DOES NOT CONFORM TO SIMPLE PARTICLE COLLISION THEORY

1987 ◽  
Author(s):  
Moideen P Jamaluddin
Keyword(s):  
Platelet Aggregation ◽  
Rate Equation ◽  
Rate Constants ◽  
Kinetic Scheme ◽  
Order Type ◽  
Second Order ◽  
Particle Collision ◽  
Collision Theory ◽  
Rate Law ◽  
First Order

Platelet aggregation kinetics, according to the particle collision theory, generally assumed to apply, ought to conform to a second order type of rate law. But published data on the time-course of ADP-induced single platelet recruitment into aggregates were found not to do so and to lead to abnormal second order rate constants much larger than even their theoretical upper bounds. The data were, instead, found to fit a first order type of rate law rather well with rate constants in the range of 0.04 - 0.27 s-1. These results were confirmed in our laboratory employing gelfiltered calf platelets. Thus a mechanism much more complex than hithertofore recognized, is operative. The following kinetic scheme was formulated on the basis of information gleaned from the literature.where P is the nonaggregable, discoid platelet, A the agonist, P* an aggregable platelet form with membranous protrusions, and P** another aggregable platelet form with pseudopods. Taking into account the relative magnitudes of the k*s and assuming aggregation to be driven by hydrophobic interaction between complementary surfaces of P* and P** species, a rate equation was derived for aggregation. The kinetic scheme and the rate equation could account for the apparent first order rate law and other empirical observations in the literature.

Comparative QSAR evidence for a free-radical mechanism of phenol-induced toxicity

2000 ◽  
Vol 127 (1) ◽  
pp. 61-72 ◽  
Author(s):  
Corwin Hansch ◽  
Susan C. McKarns ◽  
Carr J. Smith ◽  
David J. Doolittle
Keyword(s):  
Free Radical ◽  
Radical Mechanism ◽  
Free Radical Mechanism

Catalytic etherification of glycerol to tert-butyl glycerol ethers using tert-butanol over sulfonic acid functionalized mesoporous polymer

RSC Advances ◽  
2016 ◽  
Vol 6 (86) ◽  
pp. 82654-82660 ◽  
Author(s):  
Pandian Manjunathan ◽  
Manish Kumar ◽  
Sathyapal R. Churipard ◽  
S. Sivasankaran ◽  
Ganapati V. Shanbhag ◽  
...  
Keyword(s):  
Free Radical ◽  
Radical Polymerization ◽  
Sulfonic Acid ◽  
Solvothermal Method ◽  
Free Radical Polymerization ◽  
Tert Butyl ◽  
Mesoporous Polymer ◽  
Glycerol Ethers ◽  
Tert Butanol

Mesoporous polymers (MP) were synthesized by free radical polymerization of divinylbenzene by a solvothermal method followed by sulfonic acid functionalization by a post synthetic modification with conc.

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