Separation of Ozone from Oxygen by a Sorption Process

Cook, Gerhard A.; Kiffer, A. D.; Klumpp, Charles V.; Malik, Amrita; Spence, L. A.

doi:10.1021/ba-1959-0021.ch007

Cited by 26 publications

(10 citation statements)

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“…Activated complex theory predicts ( 7 ) kT Q* h Q B~ Qo3 where the quantities have their usual meanings. Collinear interaction is assumed, and the configuration at the barrier maximum (E, z 1.2 kcal/mol from the present work and [I]) is determined with the BEBO method from both the measured activation energy and the bond strength for the 0-0 bond in ozone (24.0 kcal/mol) [ll].…”

Section: Resultsmentioning

confidence: 99%

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Absolute rate constants for the reaction of bromine atoms with ozone from 234 to 360 K

Michael

Payne

1979

Int J of Chemical Kinetics

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The rate constant for the reaction of Br + 0 3 -BrO + 0 2 has been measured a t four temperatures from 234 to 360 K by the technique of discharge flow coupled with resonance-fluorescence detection of bromine atoms. The measured rate constants obey the Arrhenius expression k = (9.45 f 2.48) X exp(-659 f 64/T) cm3/molec-sec (one standard deviation). The results are compared with two previous studies, one of which utilized the flashphotolysis-resonance-fluorescence technique and the other utilized the discharge-flowmass-spectrometric technique. The result is also discussed from a theoretical point of view.

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Section: Resultsmentioning

confidence: 99%

“…Ozone was prepared from an electrical discharge in 0 2 and was collected in a liquid Nz-cooled trap on silica gel [7]. The sample was thoroughly out-gassed a t 260 K and was then expanded into a 5-liter storage bulb a t 5-15 Torr (measured with a precalibrated Wallace and Tiernan 0-20 Torr range pressure gauge).…”

Section: Methodsmentioning

confidence: 99%

Absolute rate constants for the reaction of bromine atoms with ozone from 234 to 360 K

Michael

Payne

1979

Int J of Chemical Kinetics

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“…Ozone is produced in an AC discharge from molecular oxygen (99.99%) with 2−4% efficiency and adsorbed in a cylinder filled with silica gel at about −110 °C. , Excess molecular oxygen is removed from the silica gel trap by evacuation at liquid nitrogen temperatures. An adjustable ozone partial pressure in the cell is then maintained by passing a measured flow rate of Ar through the ozone trap at a warmer but fixed temperature.…”

Section: Methodsmentioning

confidence: 99%

Time-Resolved O₃ Chemical Chain Reaction Kinetics via High-Resolution IR Laser Absorption Methods

et al. 1998

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Excimer laser photolysis in combination with time-resolved IR laser absorption detection of OH radicals has been used to study O3/OH(v = 0)/HO2 chain reaction kinetics at 298 K, (i.e., OH + O3 HO2 + O2 and HO2 + O3 OH + 2O2). From time-resolved detection of OH radicals with high-resolution near IR laser absorption methods, the chain induction kinetics have been measured at up to an order of magnitude higher ozone concentrations ([O3] ≤ 1017 molecules/cm3) than accessible in previous studies. This greater dynamic range permits the full evolution of the chain induction, propagation, and termination process to be temporally isolated and measured in real time. An exact solution for time-dependent OH evolution under pseudo- first-order chain reaction conditions is presented, which correctly predicts new kinetic signatures not included in previous OH + O3 kinetic analyses. Specifically, the solutions predict an initial exponential loss (chain “induction”) of the OH radical to a steady-state level ([OH]ss), with this fast initial decay determined by the sum of both chain rate constants, k ind = k 1 + k 2. By monitoring the chain induction feature, this sum of the rate constants is determined to be k ind = 8.4(8) × 10-14 cm3 molecule-1 s-1 for room temperature reagents. This is significantly higher than the values currently recommended for use in atmospheric models, but in excellent agreement with previous results from Ravishankara et al. [J. Chem. Phys. 1979, 70, 984].

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“…Toward overcoming issues associated with solvent degradation in challenging ozone-mediated oxidations, Mazur et al developed a strategy to adsorb substrates onto silica gel to act as a solid matrix (Scheme B) . In many ways, silica is an ideal solvent-replacement: it is inexpensive, reusable, inert to ozone, and able to adsorb ozone more efficiently than most organic solvents, particularly at cryogenic temperatures. − With this approach, oxidation of C–H bonds to form alcohols or ketones and oxidation of amines to nitroalkanes were reported with improved yields and selectivity compared to use of organic solvents . While this represented a substantial improvement over previously reported liquid-phase oxidations, there are still many limitations that have kept this chemistry from being used.…”

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confidence: 99%

Ozone-Mediated Amine Oxidation and Beyond: A Solvent-Free, Flow-Chemistry Approach

2021

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Ozone is a powerful oxidant, most commonly used for oxidation of alkenes to carbonyls. The synthetic utility of other ozone-mediated reactions is hindered by its high reactivity and propensity to over-oxidize organic molecules, including most solvents. This challenge can largely be mitigated by adsorbing both substrate and ozone onto silica gel, providing a solvent-free oxidation method. In this manuscript, a flow-based packed bed reactor approach is described that provides exceptional control of reaction temperature and time of this reaction to achieve improved control and chemoselectivity over this challenging reaction. A powerful method to oxidize primary amines into nitroalkanes is achieved. Examples of pyridine, C-H bond, and arene oxidations are also demonstrated, confirming the system is generalizable to diverse ozone-mediated processes. File list (2) download file view on ChemRxiv Manuscript.pdf (1.38 MiB) download file view on ChemRxiv Supporting information.pdf (3.03 MiB)

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Separation of Ozone from Oxygen by a Sorption Process

Cited by 26 publications

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Absolute rate constants for the reaction of bromine atoms with ozone from 234 to 360 K

Absolute rate constants for the reaction of bromine atoms with ozone from 234 to 360 K

Time-Resolved O₃ Chemical Chain Reaction Kinetics via High-Resolution IR Laser Absorption Methods

Ozone-Mediated Amine Oxidation and Beyond: A Solvent-Free, Flow-Chemistry Approach

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Separation of Ozone from Oxygen by a Sorption Process

Cited by 26 publications

References 0 publications

Absolute rate constants for the reaction of bromine atoms with ozone from 234 to 360 K

Absolute rate constants for the reaction of bromine atoms with ozone from 234 to 360 K

Time-Resolved O3 Chemical Chain Reaction Kinetics via High-Resolution IR Laser Absorption Methods

Ozone-Mediated Amine Oxidation and Beyond: A Solvent-Free, Flow-Chemistry Approach

Contact Info

Product

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Time-Resolved O₃ Chemical Chain Reaction Kinetics via High-Resolution IR Laser Absorption Methods