A partial pressure monitor and controller for stable ozone flow from a silica gel trap

Stevens, Richard E.; Hsiao, Chih-Wei; Le, Linh; Curro, N. J.; Monton, B. J.; Chang, Bor-Yu; Kung, Chung-Yi; Kittrell, Carter; Kinsey, James L.

doi:10.1063/1.1148950

Cited by 2 publications

(2 citation statements)

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“…Flow chemistry is a well-established technology for improving reproducibility, enhancing mass/heat transfer, and providing finer control over process parameters compared to batch. In addition, it has been previously established that ozone-mediated reactions can be scaled up in flow while still minimizing associated safety risks through a variety of proposed systems. − For these reasons, we proposed that a flow system would be ideal for safely performing underutilized ozone-mediated oxidation reactions. While several powerful oxidation procedures have been developed since this field’s inception, ozone remains an appealing inexpensive and atom economical oxidant.…”

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

2021

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“…Ultrahigh purity N 2 O (99.99%) and He (99.999%) were purchased from Matheson Tri-Gas and Airgas, respectively, and used without any further purification. O 3 was generated by a commercial ozonator and kept in a silica gel trap at −78 °C …”

Section: Methodsmentioning

confidence: 99%

O(¹D) + N₂O Reaction: NO Vibrational and Rotational Distributions

et al. 2010

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The O((1)D) + N(2)O → 2NO(X (2)Π) reaction has been studied in a molecular beam experiment in which O(3) and N(2)O were coexpanded. The precursor O((1)D) was prepared by O(3) photodissociation at 266 nm, and the NO(X (2)Π) molecules born from the reaction as the O((1)D) recoiled out of the beam were detected by 1+1 REMPI over the 220-246 nm probe laser wavelength range. The resulting spectrum was simulated to extract rotational and vibrational distributions of the NO(X (2)Π) molecules. The product rotational distribution is found to be characterized by a constant rotational temperature of ≈4500 K for all observed bands, v = 0-9. An inverted vibrational distribution is observed. A consistent explanation of this and previous experimental results is possible if there are two channels for the reaction, one producing a nearly statistical vibrational distribution for low O((1)D)-N(2)O relative velocity collisions and a second producing the inverted distribution observed here for high relative velocity collisions. The former might correspond to an insertion/complex-formation reaction, while the latter might correspond to a stripping reaction. Velocity relaxation of the O((1)D) is argued to compete strongly with reaction in most bulb studies, so that these studies see predominantly the nearly statistical distribution. In contrast, the beam experiments do not detect the part of the vibrational distribution produced in low relative velocity reactions because the O((1)D) is not relaxed from its initial velocity before it either reacts or leaves the beam.

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A partial pressure monitor and controller for stable ozone flow from a silica gel trap

Cited by 2 publications

References 12 publications

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

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

O(¹D) + N₂O Reaction: NO Vibrational and Rotational Distributions

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A partial pressure monitor and controller for stable ozone flow from a silica gel trap

Cited by 2 publications

References 12 publications

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

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

O(1D) + N2O Reaction: NO Vibrational and Rotational Distributions

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O(¹D) + N₂O Reaction: NO Vibrational and Rotational Distributions