Catalytic resonance theory: parallel reaction pathway control

Catalytic enhancement of chemical reactions via heterogeneous materials occurs through stabilization of transition states at designed active sites, but dramatically greater rate acceleration on that same active site is achieved when the surface intermediates oscillate in binding energy. The applied oscillation amplitude and frequency can accelerate reactions orders of magnitude above the catalytic rates of static systems, provided the active site dynamics are tuned to the natural frequencies of the surface chemistry. In this work, differences in the characteristics of parallel reactions are exploited via selective application of active site dynamics (0 < ΔU < 1.0 eV amplitude, 10-6 < f < 104 Hz frequency) to control the extent of competing reactions occurring on the shared catalytic surface. Simulation of multiple parallel reaction systems with broad range of variation in chemical parameters revealed that parallel chemistries are highly tunable in selectivity between either pure product, even when specific products are not selectively produced under static conditions. Two mechanisms leading to dynamic selectivity control were identified: (i) surface thermodynamic control of one product species under strong binding conditions, or (ii) catalytic resonance of the kinetics of one reaction over the other. These dynamic parallel pathway control strategies applied to a host of chemical conditions indicate significant potential for improving the catalytic performance of many important industrial chemical reactions beyond their existing static performance.

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Catalytic Resonance Theory: Parallel Reaction Pathway Control

10.26434/chemrxiv.10271090.v1 ◽

2019 ◽

Author(s):

M. Alexander Ardagh ◽

Manish Shetty ◽

Anatoliy Kuznetsov ◽

Qi Zhang ◽

Phillip Christopher ◽

...

Keyword(s):

Chemical Reactions ◽

Active Site ◽

Active Sites ◽

Reaction Pathway ◽

Control Strategies ◽

Oscillation Amplitude ◽

Catalytic Performance ◽

Parallel Reaction ◽

Resonance Theory ◽

Static Conditions

Catalytic enhancement of chemical reactions via heterogeneous materials occurs through stabilization of transition states at designed active sites, but dramatically greater rate acceleration on that same active site is achieved when the surface intermediates oscillate in binding energy. The applied oscillation amplitude and frequency can accelerate reactions orders of magnitude above the catalytic rates of static systems, provided the active site dynamics are tuned to the natural frequencies of the surface chemistry. In this work, differences in the characteristics of parallel reactions are exploited via selective application of active site dynamics (0 < ΔU < 1.0 eV amplitude, 10-6 < f < 104 Hz frequency) to control the extent of competing reactions occurring on the shared catalytic surface. Simulation of multiple parallel reaction systems with broad range of variation in chemical parameters revealed that parallel chemistries are highly tunable in selectivity between either pure product, even when specific products are not selectively produced under static conditions. Two mechanisms leading to dynamic selectivity control were identified: (i) surface thermodynamic control of one product species under strong binding conditions, or (ii) catalytic resonance of the kinetics of one reaction over the other. These dynamic parallel pathway control strategies applied to a host of chemical conditions indicate significant potential for improving the catalytic performance of many important industrial chemical reactions beyond their existing static performance.

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Activated Self‐Resolution and Error‐Correction in Catalytic Reaction Networks

Chemistry - A European Journal ◽

10.1002/chem.202100208 ◽

2021 ◽

Author(s):

Fredrik Schaufelberger ◽

Olof Ramström

Keyword(s):

Error Correction ◽

Catalytic Reaction ◽

Reaction Networks

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One-Step Simultaneous Differential Scanning Calorimetry-FTIR Microspectroscopy to Quickly Detect Continuous Pathways in the Solid-State Glucose/Asparagine Maillard Reaction

Journal of AOAC International ◽

10.5740/jaoacint.13-074 ◽

2013 ◽

Vol 96 (6) ◽

pp. 1362-1364 ◽

Cited By ~ 1

Author(s):

Deng-Fwu Hwang ◽

Tzu-Feng Hsieh ◽

Shan-Yang Lin

Keyword(s):

Differential Scanning Calorimetry ◽

Solid State ◽

Maillard Reaction ◽

Reaction Pathway ◽

Molar Ratio ◽

Maillard Reaction Products ◽

Reaction Products ◽

Scanning Calorimetry ◽

Ftir Microspectroscopy ◽

Amadori Product

Abstract The stepwise reaction pathway of the solid-state Maillard reaction between glucose (Glc) and asparagine (Asn) was investigated using simultaneous differential scanning calorimetry (DSC)-FTIR microspectroscopy. The color change and FTIR spectra of Glc-Asn physical mixtures (molar ratio = 1:1) preheated to different temperatures followed by cooling were also examined. The successive reaction products such as Schiff base intermediate, Amadori product, and decarboxylated Amadori product in the solid-state Glc-Asn Maillard reaction were first simultaneously evidenced by this unique DSC-FTIR microspectroscopy. The color changed from white to yellow-brown to dark brown, and appearance of new IR peaks confirmed the formation of Maillard reaction products. The present study clearly indicates that this unique DSC-FTIR technique not only accelerates but also detects precursors and products of the Maillard reaction in real time.

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On-line Analysis of Catalytic Reaction Products Using a High-Pressure Tandem Micro-reactor GC/MS

Analytical Sciences ◽

10.2116/analsci.33.1085 ◽

2017 ◽

Vol 33 (9) ◽

pp. 1085-1089 ◽

Cited By ~ 4

Author(s):

Atsushi WATANABE ◽

Young-Min KIM ◽

Akihiko HOSAKA ◽

Chuichi WATANABE ◽

Norio TERAMAE ◽

...

Keyword(s):

High Pressure ◽

Catalytic Reaction ◽

Reaction Products ◽

On Line ◽

Micro Reactor ◽

Line Analysis

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Reactions of Titanocene- and Zirconocene-Bis(trimethylsilyl)acetylene Complexes with Selected Heterocyclic and Aromatic NH and OH Acid Compounds

Collection of Czechoslovak Chemical Communications ◽

10.1135/cccc20070475 ◽

2007 ◽

Vol 72 (4) ◽

pp. 475-491 ◽

Cited By ~ 6

Author(s):

Perdita Arndt ◽

Vladimir V. Burlakov ◽

Ulrike Jäger-Fiedler ◽

Marcus Klahn ◽

Anke Spannenberg ◽

...

Keyword(s):

Bond Activation ◽

Reaction Pathway ◽

Reaction Products ◽

X Ray ◽

X Ray Crystallography

The titanocene complexes Cp'2Ti(η2-Me3SiC2SiMe3) (Cp' = Cp (1), Cp* (2)) react with pyrrole under the formation of the titanium(III) mono-N-pyrrolides Cp'2Ti(NC4H4) (Cp' = Cp (6), Cp* (7)); whereas the corresponding zirconocene system Cp2Zr(η2-Me3SiC2SiMe3)(thf) (3) forms in a different reaction pathway first the Cp2Zr(NC4H4)[C(SiMe3)=CH(SiMe3)] (8) and then the zirconium(IV) bis-N-pyrrolide Cp2Zr(NC4H4)2 (11). With Cp*2Zr(η2-Me3SiC2SiMe3) (4) and pyrrole, the zirconium(IV) mono-N-pyrrolide with an agostic alkenyl group Cp*2Zr(NC4H4)[C(SiMe3)=CH(SiMe3)] (9) was obtained. In the reaction of the ethylenebistetrahydroindenyl (ebthi) complex rac-(ebthi)Zr(η2-Me3SiC2SiMe3) (5) with 2,3,5,6-tetrafluoroaniline under N-H bond activation, a complex with an agostic alkenyl group rac-(ebthi)Zr(NH-C6HF4)[C(SiMe3)=CH(SiMe3)] (10) was formed. Compound 10 reacts with additional 2,3,5,6-tetrafluoroaniline to give the bisanilide rac-(ebthi)Zr(NH-C6HF4)2 (12) which was obtained directly from 5 with two equivalents of 2,3,5,6-tetrafluoroaniline. In reactions of complex 5 with unsubstituted aniline to rac-(ebthi)Zr(NH-C6H5)2 (13) and with pentafluorophenol to bisphenolate rac-(ebthi)Zr(O-C6F5)2 (14), no intermediates could be isolated. The new reaction products 6, 9, 10, 12, 13 and 14 were investigated by X-ray crystallography.

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Multi Component Reactions under Increased Pressure: On the Mechanism of Formation of Pyridazino[5,4,3-de][1,6]naphthyridine Derivatives from Reaction of Malononitrile, Aldehyde and 2-Oxoglyoxalarylhydrazones in Q-Tubes

10.20944/preprints201710.0110.v1 ◽

2017 ◽

Author(s):

Majdah A. AL-Johani ◽

Khadijah M. Al-Zaydi ◽

Sameera M. Mousally ◽

Norah F. Alqahtani ◽

Mohamed H. Elnagdi

Keyword(s):

Crystal Structure ◽

Reaction Pathway ◽

Aromatic Aldehydes ◽

Reaction Products ◽

Mechanism Of Formation ◽

X Ray ◽

Alternate Pathway ◽

Considerable Research ◽

Increased Pressure ◽

Chemical Evidence

The considerable biological and medicinal activities of pyridazines has stimulated considerable research on efficient syntheses of these derivatives. In the last decade, microwave irradiation has generally been used for the energy source. As demonstrated in recent studies, pressure reactor “Q-tubes” may be used to accelerate several of these reactions in a more optimal and safer manner (compared to microwaves). In these studies there has been postulated a pathway for the formation of pyridazino[5,4,3-de][1,6]naphthyridine derivatives . In this paper we consider this pathway, and an alternate pathway, for several reactions. Contrary to the suggestion in these studies the pathway in which initial dimerization of malononitrile was postulated could be excluded based on chemical evidence. The reactions performed were the reaction of arylhydrazonals 1a,b with benzylidinemalononitrile which afforded in Q-tube the 3-acyl-4-aryl-1-phenyl-6-amino-1,4-dihydropyridazines, and the reaction of arylhydrazonals 1a,b, malononitrile 9 and aromatic aldehydes 10a-g in Q-tubes which afforded the tricyclic systems 12a-n whose structure could be established by X-ray crystal structure determination. In conclusion, we have added to the work of the recent studies by excluding a reaction pathway for one of their reaction products.

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