Mechanism of oxidative carbonylation of phenylacetylene and methylacetylene. Generation and experimental discrimination of hypotheses

Брук, Л. Г.; Gorodskii, S. N.; Zeigarnik, Andrew V.; Valdés-Pérez, Raúl E.; Темкин, О. Н.

doi:10.1007/bf02494629

Cited by 4 publications

(4 citation statements)

References 11 publications

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“…Using a PdI 2 -KI catalyst with alkynes under mild conditions, high catalytic efficiencies have been achieved leading to a mixture of dicarbonylation products [2]. When phenylacetylene (PhAc) was used as the substrate in methanol (palladium-catalyzed phenylacetylene oxidative carbonylation, PCPOC), oscillations in pH, redox potential and gas uptake (CO and O 2 ) were discovered [3][4][5][6][7]. Further study of this reaction using power compensation calorimetry found the oscillations in pH were accompanied by oscillations in heat of reaction, Q r [8].…”

Section: Introductionmentioning

confidence: 99%

Autonomous reorganization of the oscillatory phase in the PdI2 catalyzed phenylacetylene carbonylation reaction

Parker

Novakovic

2016

Reac Kinet Mech Cat

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The PdI 2 catalyzed oxidative carbonylation of phenylacetylene has been shown to produce pH oscillations over the temperature range 0-40°C under semibatch conditions. The decrease in reaction temperature resulted in an increase in the period and amplitude of the pH oscillations. In addition, reducing the reaction temperature enabled the observation of different phases in the oscillatory pH behavior confirming the ability of the reaction system to autonomously produce multiple clusters of oscillatory phases. Sets of pH oscillations were recorded at 0 and 10°C. At temperatures of 0-20°C, oscillations commenced as pH was falling during the initial stages of the reaction while, at 30 and 40°C, the oscillations commenced once the pH started to increase after the initial drop. Oscillations in turbidity were observed at 20 and 30°C. Experiments were conducted in an HEL Simular reaction calorimeter enabling precise temperature control. Operating at 0°C reduced the reaction rate prolonging the duration of pH oscillations. The oscillatory pH behavior was recorded for 11 days without additional substrate at which point the run was terminated although the oscillations would likely have continued.

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Section: Introductionmentioning

confidence: 99%

Autonomous reorganization of the oscillatory phase in the PdI2 catalyzed phenylacetylene carbonylation reaction

Parker

Novakovic

2016

Reac Kinet Mech Cat

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“…For this reason, several groups proposed the application of computers for the generation of reaction mechanisms and analysis of the results. − The number of generated reactions increases in a factorial measure with the increasing number of species, and this increase is even more pronounced if large molecules are involved. Therefore, most of these proposals encode expert chemical knowledge in order to avoid including unlikely reactions into the program.…”

Section: Introductionmentioning

confidence: 99%

“…MECHEM and ChemNet meet the latter requirement. − They carry out mechanism elucidation by knowledge guided search within a combinatorial space to find the simplest plausible mechanisms. Thermodynamics is not incorporated into them, and they were applied mostly to catalytic reactions.…”

Section: Introductionmentioning

confidence: 99%

MECHGEN: Computer Aided Generation and Reduction of Reaction Mechanisms

Németh

Vidóczy

Héberger

et al. 2002

J. Chem. Inf. Comput. Sci.

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The paper describes selection rules implemented in a software generating "possible reaction mechanism", i.e. a set of elementary reactions chosen from all stoichiometrically possible reactions. The novelty of the approach lies in the fact that the user has to define all species involved (reactants, intermediates, products), and the rules applied with user-set limits reduce the resulting mechanism to a reasonable set of possible elementary reactions. The computer code consists of five parts: (i) definition of species, and introducing its characteristics (structure and thermodynamic data); (ii) definition of the reacting system and generation of all stoichiometrically possible reactions; (iii) reduction of the mechanisms using complexity and thermodynamic constraints based on user-set limits; (iv) calculation of the resulting pathways (routes of the various atoms or groups of atoms transferred from one species to another); and (v) tools to help visualization of the process by finding those elementary processes which realize a given pathway. Reasonable flexibility is ensured for using selection rules based on various criteria with limits set by the user. The various pathways are shown (in a matrix form), which offers an overview of the entire process.

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“…The elementary steps tbund at the first stage served as input for MECHEM. In an experimental study ofoxidative carbonylation of phenylacetylenecatalyzed by Pd I1 and Cu I complexes 12,16,17 PhC-=CH + CO + MeOH + 2 NaOAc + 2 CuCl 2 --~ PhC-=CCOOMe + 2 AcOH + 2 NaCI + 2 CuCI, we proposed, with the assistance of a computer, 41 hypothetical mechanisms. Using these mechanisms, we were able to design a target-directed experiment based on the measurement of the kinetic isotope effect.…”

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confidence: 99%

Computer-assisted generation of chemical reaction networks. Applications in mechanistic studies of organometallic catalysis

et al. 1999

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The ChemNet computer program designed for mechanistic studies of or~nic reactions occurring in solutions of metal complexes and on the sudb.ce of heterogeneous catalysts is proposed. The use of the program is illustrated by applications to catalyzed homogeneous hydrocarboxylation and hydrotbrmylation of ethylene and heterogeneous bydrogenolysis of ethane.Key words: reaction mechanisms, application of computers, ChemNet program, ethane hydrogenolysis, ethylene hydrocarboxylation, ethylene hydroformylation, organometallic catalysis Our recent studies on reaction mechanisms are based on the following three ideas: ( 1 ) any hypothetical mechanism cannot be proven but can only be rejected; (2) consideration of many hypothetical mechanisms for each particular reaction leads to more reliable reaction mechanisms and kinetic models based on them while lowering time and expenses for experimental studies: (3) hypothetical mechanisms can be proposed most efficiently using computer programs, which help the researcher (but do not replace him!). Computer programs permit the formulation and protocol of the initial data that are used to advance the hypotheses. A set of hypothetical mechanisms obtained using computer programs is complete within the specified set of constraints. Various aspects of this methodology t-t2 and related computer software 6,8-t2 have been considered in our publications. Some philosophical problems faced by a researcher in studies of reaction mechanisms were noted in a popular monograph,t3 while some methodological aspects were described in a textbook, t4. This paper is devoted to the computer program ChemNet, which we developed and used to study the mechanisms of catalytic reactions. 6,8 In a recent publication t5 we demonstrated that several programs can be used together to advance mechanistic hypotheses on reaction mechanisms. In particular, one program (ChemNet) was used to generate a reaction network (a set of elementary steps allowed by the given constraints),, and another program (MECHEM) was employed to find the simplest mechanisms. The elementary steps tbund at the first stage served as input for MECHEM. In an experimental study ofoxidative carbonylation of phenylacetylenecatalyzed by Pd I1 and Cu I complexes 12,16,17PhC-=CH + CO + MeOH + 2 NaOAc + 2 CuCl 2 --~ PhC-=CCOOMe + 2 AcOH + 2 NaCI + 2 CuCI, we proposed, with the assistance of a computer, 41 hypothetical mechanisms. Using these mechanisms, we were able to design a target-directed experiment based on the measurement of the kinetic isotope effect. Of the 41 mechanisms, 32 were rejected based on this experimentlZ,16; we intended to veri~" the remaining mechanisms by other methods.No publications devoted to the ChemNet program proper are available. The changes introduced recently into the program stimulated us to write this paper. Description of the ChemNet programThe program uses initial data of three types, namely, starting compounds, transforms, and constraints. The program cannot run without any of these elements. The starting compounds a...

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Mechanism of oxidative carbonylation of phenylacetylene and methylacetylene. Generation and experimental discrimination of hypotheses

Cited by 4 publications

References 11 publications

Autonomous reorganization of the oscillatory phase in the PdI2 catalyzed phenylacetylene carbonylation reaction

Autonomous reorganization of the oscillatory phase in the PdI2 catalyzed phenylacetylene carbonylation reaction

MECHGEN: Computer Aided Generation and Reduction of Reaction Mechanisms

Computer-assisted generation of chemical reaction networks. Applications in mechanistic studies of organometallic catalysis

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