Anisotropic Scattering Model for Estimation of Light Absorption Rates in Photoreactor with Heterogeneous Medium.

Yokota, Toshiyuki; Cesur, Serap; Suzuki, Hiroshi; Baba, Hayato; Takahata, Yasuyuki

doi:10.1252/jcej.32.314

Cited by 32 publications

(27 citation statements)

References 7 publications

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“…Radiative transfer in absorbing, reacting, and scattering reaction media has been properly described by a set of integral‐differential equations,14 commonly solved with one of three numerical frameworks: Monte Carlo (MC) approaches15, 16; discrete ordinate (DO) models17, 18; and a conservative finite‐volume (FV) variant of the DO model 19, 20. These models have been used to determine radiation fields in pseudo homogeneous photoreactors, expressed as the local volumetric rate of energy absorption (LVREA) within regions of the reactor bulk 21, 22.…”

Section: Introductionmentioning

confidence: 99%

Unravelling the Reaction Path of Rhodium–MonoPhos‐Catalysed Olefin Hydrogenation

Alberico

Baumann

Vries

et al. 2011

Chemistry A European J

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The mechanism of the asymmetric hydrogenation of methyl (Z)-2-acetamidocinnamate (mac) catalysed by [Rh(MonoPhos)(2)(nbd)]SbF(6) (MonoPhos: 3,5-dioxa-4-phosphacyclohepta[2,1-a:3,4-a']dinaphthalen-4-yl)dimethylamine) was elucidated by using (1)H, (31)P and (103)Rh NMR spectroscopy and ESI-MS. The use of nbd allows one to obtain in pure form the rhodium complex that contains two units of the ligand. In contrast to the analogous complexes that contain cis,cis-1,5-cyclooctadiene (cod), this complex shows well-resolved NMR spectroscopic signals. Hydrogenation of these catalyst precursors at 1 bar total pressure gave rise to the formation of a bimetallic complex of general formula [Rh(MonoPhos)(2)](2)(SbF(6))(2); no solvate complexes were detected. In the dimeric complex both rhodium atoms are ligated to two MonoPhos ligands but, in addition, each rhodium atom also binds to one of the binaphthyl rings of a ligand that is bound to the other rhodium metal. Upon addition of mac, a mixture of diastereomeric complexes [Rh(MonoPhos)(2)(mac)]SbF(6) is formed in which the substrate is bound in a chelate fashion to the metal. Upon hydrogenation, these adducts are converted into a new complex [Rh(MonoPhos)(2){mac(H)(2)}]SbF(6) in which the methyl phenylalaninate mac(H)(2) is bound through its aromatic ring to rhodium. Addition of mac to this complex leads to displacement of the product by the substrate. No hydride intermediates could be detected and no evidence was found for the involvement at any stage of the process of complexes with only one coordinated MonoPhos. The collected data suggest that the asymmetric hydrogenation follows a Halpern-like mechanism in which the less abundant substrate-catalyst adduct is preferentially hydrogenated to phenylalanine methyl ester.

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Section: Introductionmentioning

confidence: 99%

Unravelling the Reaction Path of Rhodium–MonoPhos‐Catalysed Olefin Hydrogenation

Alberico

Baumann

Vries

et al. 2011

Chemistry A European J

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“…In addition to mass and momentum balances, multiphase photocatalytic reactor analysis requires the simultaneous solution of the radiative transport equation (RTE) -an integro-differential expression which accounts for spatial light intensity distribution within the vessel -with the Navier-Stokes balances. Cassano and co-workers [25,26], Yokota et al [27,28] and Santarelli and collaborators [29,30] have made important pioneering contributions to the numerical solution of the RTE in order to predict light-scattering in photoreactors. Their analysis permitted the evaluation of the local volumetric rate of energy absorption (LVREA) for the particular reactor configuration and lamp arrangement.…”

Section: Pilot-scale Trialsmentioning

confidence: 99%

Industrial exploitation of photocatalysis: progress, perspectives and prospects

Adesina

2004

Catal Surv Asia

151

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The removal of numerous organic pollutants from aqueous media using titania photocatalysis has motivated the need for commercial application of this technology for tertiary wastewater treatment and water purification. A discussion of the development of visible light-activating catalysts, pilot-scale multiphase reactor analysis and case studies with industrial significance is presented. An overview of different solar photocatalytic reactors is also given.

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“…Many of these processes involve the photoexcitation of either a reactant or catalyst as a limiting step governing reaction kinetics, whereby the UV absorption profile within a reactor geometry for a given light source is a determining factor in the system's performance and optimum configuration. A number of radiative transfer models exist for predicting the UV absorption profile for absorbing, reacting, and scattering media, based on one of the three computational approaches: Monte Carlo, discrete ordinate (DO) models, and a conservative finite‐volume variant of the DO model . Previous work on a computationally robust DO implementation for corrugated reactor geometries has enabled the determination of local area‐specific rates of energy absorption (LASREA) for practical reactor configurations illuminated by complex light sources, which can be coupled with local mass‐transfer rates to optimize reacting systems .…”

Section: Introductionmentioning

confidence: 99%

Rotating corrugated photoreactor design: Experimental and computational analysis of TiO₂‐based photocatalysis

Donaldson

McEvoy

et al. 2012

AIChE Journal

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A TiO 2 -coated rotating corrugated reactor is experimentally characterized and simulated for ultraviolet (UV)-based photo degradation of methylene blue (MB). Using degradation kinetics derived from flat-plate experiments and finiteelement discrete-ordinate models simulating spatially and temporally varying radiation patterns from a UV-lamp array, the simulated reactor performance is experimentally validated and extended to explore the impact of geometry variations. Mass-transfer limitations between the corrugated surface and the reservoir bulk are identified as a determining factor in the degradation rate of MB. Optimization studies suggest minimizing the corrugation half-angle to improve reactor performance for a given area, increasing the number of corrugations rather than the corrugation depth subject to practical limitations arising from undesirable bubble formation at small aperture widths. Given the relevance of mass transfer to this system, future work is needed to elucidate the experimental impact of reservoir volume and geometry while validating the use of flat-plate correlations for mass transfer.

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Anisotropic Scattering Model for Estimation of Light Absorption Rates in Photoreactor with Heterogeneous Medium.

Cited by 32 publications

References 7 publications

Unravelling the Reaction Path of Rhodium–MonoPhos‐Catalysed Olefin Hydrogenation

Unravelling the Reaction Path of Rhodium–MonoPhos‐Catalysed Olefin Hydrogenation

Industrial exploitation of photocatalysis: progress, perspectives and prospects

Rotating corrugated photoreactor design: Experimental and computational analysis of TiO₂‐based photocatalysis

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Anisotropic Scattering Model for Estimation of Light Absorption Rates in Photoreactor with Heterogeneous Medium.

Cited by 32 publications

References 7 publications

Unravelling the Reaction Path of Rhodium–MonoPhos‐Catalysed Olefin Hydrogenation

Unravelling the Reaction Path of Rhodium–MonoPhos‐Catalysed Olefin Hydrogenation

Industrial exploitation of photocatalysis: progress, perspectives and prospects

Rotating corrugated photoreactor design: Experimental and computational analysis of TiO2‐based photocatalysis

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Product

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Rotating corrugated photoreactor design: Experimental and computational analysis of TiO₂‐based photocatalysis