scholarly journals Kinetic Study of Disulfonimide Catalyzed Cyanosilylation of Aldehyde Using a Method of Progress Rates

2020 ◽  
Author(s):  
Zhipeng Zhang ◽  
Martin Klussmann ◽  
Benjamin List
Keyword(s):  
Kinetic Study ◽  
Kinetic Data ◽  
Continuous Monitoring ◽  
Reaction Rates ◽  
Catalytic Reactions ◽  
Bond Forming ◽  
Enthalpy Of Activation ◽  
Entropy Of Activation ◽  
Ft Ir

Kinetic study of organic reactions, especially multistep catalytic reactions, is crucial to in-depth understanding of reaction mechanisms. Here we report our kinetic study of the chiral disulfonimide catalyzed cyanosilylation of aldehyde, which reveals that two molecules of TMSCN are involved in the rate-determining C-C bond forming step. In addition, the apparent activation energy, enthalpy of activation and entropy of activation were deduced through the study of temperature dependence of the reaction rates. More importantly, a novel and efficient method which makes use of the progress rates was developed to treat the kinetic data obtained from continuous monitoring of the reaction progress with <i>in situ</i> FT-IR.

scholarly journals Kinetic Study of Disulfonimide Catalyzed Cyanosilylation of Aldehyde Using a Method of Progress Rates

2020 ◽  
Author(s):  
Zhipeng Zhang ◽  
Martin Klussmann ◽  
Benjamin List
Keyword(s):  
Kinetic Study ◽  
Kinetic Data ◽  
Continuous Monitoring ◽  
Reaction Rates ◽  
Catalytic Reactions ◽  
Bond Forming ◽  
Enthalpy Of Activation ◽  
Entropy Of Activation ◽  
Ft Ir

Kinetic study of organic reactions, especially multistep catalytic reactions, is crucial to in-depth understanding of reaction mechanisms. Here we report our kinetic study of the chiral disulfonimide catalyzed cyanosilylation of aldehyde, which reveals that two molecules of TMSCN are involved in the rate-determining C-C bond forming step. In addition, the apparent activation energy, enthalpy of activation and entropy of activation were deduced through the study of temperature dependence of the reaction rates. More importantly, a novel and efficient method which makes use of the progress rates was developed to treat the kinetic data obtained from continuous monitoring of the reaction progress with <i>in situ</i> FT-IR.

scholarly journals Kinetic Study of Disulfonimide-Catalyzed Cyanosilylation of Aldehydes by Using a Method of Progress Rates

Synlett ◽  
2020 ◽  
Vol 31 (16) ◽  
pp. 1593-1597 ◽  
Author(s):  
Zhipeng Zhang ◽  
Martin Klussmann ◽  
Benjamin List
Keyword(s):  
Kinetic Study ◽  
Kinetic Data ◽  
Continuous Monitoring ◽  
Reaction Rates ◽  
Catalytic Reactions ◽  
In Situ Ftir ◽  
Bond Forming ◽  
Enthalpy Of Activation ◽  
Entropy Of Activation

Kinetic study of organic reactions, especially multistep catalytic reactions, is crucial to in-depth understanding of reaction mechanisms. Here we report our kinetic study on the chiral disulfonimide-catalyzed cyanosilylation of an aldehyde, which revealed that two molecules of TMSCN are involved in the rate-determining C–C bond-forming step. In addition, the apparent activation energy, enthalpy of activation, and entropy of activation were deduced through a study of the temperature dependence of the reaction rates. More importantly, a novel and efficient method that makes use of the progress rates was developed to treat kinetic data obtained by continuous monitoring of the progress of a reaction by in situ FTIR.

scholarly journals Monitoring the Interfacial Polymerization of Piperazine and Trimesoyl Chloride with Hydrophilic Interlayer or Macromolecular Additive by in-situ FT-IR Spectroscopy

2019 ◽  
Author(s):  
Xi Yang
Keyword(s):  
Ir Spectroscopy ◽  
Reaction Rate ◽  
Interfacial Polymerization ◽  
Reaction System ◽  
Reaction Rates ◽  
Water Permeation ◽  
Ft Ir ◽  
Trimesoyl Chloride ◽  
Ft Ir Spectroscopy

The interfacial polymerization (IP) of piperazine (PIP) and trimesoyl chloride (TMC) has been extensively utilized to synthesize the nanofiltration (NF) membrane. However, it is still a huge challenge to monitor the IP reaction, because of the fast reaction rate and the formed ultra-thin film. Herein, two effective strategies are applied to reduce the IP reaction rate: (1) the introduction of hydrophilic interlayers between the porous substrate and the formed polyamide layer; (2) the addition of macromolecular additives in the aqueous solution of PIP. As a result, in-situ FT-IR spectroscopy was firstly used to monitor the IP reaction of PIP/TMC reaction system, with hydrophilic interlayers or macromolecular additives. Moreover, we study the formed polyamide layer growth on the substrate, in a real-time manner. The in-situ FT-IR experimental results confirm that the IP reaction rates are effectively suppressed and the formed polyamide thickness reduces from 138&plusmn;24 nm to 46&plusmn;2 nm. Furthermore, the optimized NF membrane with excellent performance are consequently obtained, which include the boosted water permeation flux about 141~238 (L&middot;m2&middot;h/MPa) and superior salt rejection of Na2SO4 &gt; 98.4%.

Effects of Solvent Polarity on the Urethane Reaction of 1,2-Propanediol

2012 ◽  
Vol 450-451 ◽  
pp. 38-41
Author(s):  
Peng Fei Yang
Keyword(s):  
Rate Constant ◽  
Solvent Polarity ◽  
Reaction Rates ◽  
Phenyl Isocyanate ◽  
Second Order Reaction ◽  
Polar Solvents ◽  
Initial Stage ◽  
Ft Ir ◽  
Kinetics Of

The urethane reaction kinetics of 1,2-propanediol with phenyl isocyanate are investigated in different solvents, such as xylene, toluene and dimethylformamide. In-situ FT-IR is used to monitor the reaction to work out rate constant. It showsthat the urethane reaction has been found to be a second order reaction, solvents largely affects reaction rates. The reaction is largely accelerated in polar solvents, following the order of dimethylformamide > toluene > xylene. Further more, when dimethylformamide is used as solvent, the rate constants are different between initial stage and final stage, which belongs to different hydroxyls in 1,2-propanediol. However, when toluene or xylene is used as solvent, the rate constant is the same. That is, there is no reactivity difference for hydroxyls in 1,2-propanediol.

Regioselectivity of glycoluril-directed Claisen condensations — A kinetic and mechanistic study of substituent effects in the nucleophilic acyl group

2006 ◽  
Vol 84 (9) ◽  
pp. 1188-1196 ◽  
Author(s):  
Mei Chen ◽  
Katie Won ◽  
Robert S McDonald ◽  
Paul H.M Harrison
Keyword(s):  
Kinetic Data ◽  
Uv Spectroscopy ◽  
Substituent Effects ◽  
Reaction Rates ◽  
Quantitative Yield ◽  
Mechanistic Study ◽  
Claisen Condensation ◽  
Bond Forming ◽  
Rate Limiting

The Claisen-like condensation of a series of 1-arylacetyl-6-acetyl-3,4,7,8-tetramethylglycolurils (Ar = Ph, p-OMeC6H4, and p-ClC6H4) was studied in preparative experiments and by analysis of kinetic data. The reactions proceeded in virtually quantitative yield and were highly regioselective: the corresponding N-(2′-aryl-3′-ketobutanoyl)-3,4,7,8-tetramethylglycolurils were obtained in all cases, with none of the 4′-aryl regioisomers being detected. Clean bimolecular kinetics were observed for each conversion using UV spectroscopy. Reaction rates followed the order Ar = p-OMeC6H4 < Ph < p-ClC6H4. The results are explained by a mechanism in which the deprotonation of the substrates is rate-limiting; thus, deprotonation of the arylacetyl groups is favoured. The ensuing enolate reacts rapidly in the C–C bond-forming step.Key words: glycoluril, biomimetic, Claisen condensation, regioselectivity, kinetics, mechanism, substituent effects.

In-situ FT-IR spectroscopy and kinetic study of methanol synthesis from CO/H2 over ZnAl2O4 and CuZnAl2O4 catalysts

1997 ◽  
Vol 122 (2-3) ◽  
pp. 131-139 ◽  
Author(s):  
F.Le Peltier ◽  
P. Chaumette ◽  
J. Saussey ◽  
M.M. Bettahar ◽  
J.C. Lavalley
Keyword(s):  
Ir Spectroscopy ◽  
Kinetic Study ◽  
Methanol Synthesis ◽  
Ft Ir ◽  
Ft Ir Spectroscopy

scholarly journals Monitoring the Interfacial Polymerization of Piperazine and Trimesoyl Chloride with Hydrophilic Interlayer or Macromolecular Additive by In Situ FT-IR Spectroscopy

Membranes ◽  
2020 ◽  
Vol 10 (1) ◽  
pp. 12 ◽  
Author(s):  
Xi Yang
Keyword(s):  
Aqueous Solution ◽  
Ir Spectroscopy ◽  
Reaction Rate ◽  
Interfacial Polymerization ◽  
Reaction Rates ◽  
Water Permeation ◽  
Ft Ir ◽  
Trimesoyl Chloride ◽  
Ft Ir Spectroscopy

The interfacial polymerization (IP) of piperazine (PIP) and trimesoyl chloride (TMC) has been extensively utilized to synthesize nanofiltration (NF) membranes. However, it is still a huge challenge to monitor the IP reaction, because of the fast reaction rate and the formed ultra-thin film. Herein, two effective strategies were applied to reduce the IP reaction rate: (1) the introduction of hydrophilic interlayers between the porous substrate and the formed polyamide layer, and (2) the addition of macromolecular additives in the aqueous solution of PIP. As a result, in situ Fourier transform infrared (FT-IR) spectroscopy was firstly used to monitor the IP reaction of PIP/TMC with hydrophilic interlayers or macromolecular additives in the aqueous solution of PIP. Moreover, the formed polyamide layer growth on the substrate was studied in a real-time manner. The in situ FT-IR experimental results confirmed that the IP reaction rates were effectively suppressed and that the formed polyamide thickness was reduced from 138 ± 24 nm to 46 ± 2 nm according to TEM observation. Furthermore, an optimized NF membrane with excellent performance was consequently obtained, which included boosted water permeation of about 141–238 (L/m2·h·MPa) and superior salt rejection of Na2SO4 > 98.4%.

scholarly journals Monitoring the Interfacial Polymerization of Piperazine and Trimesoyl Chloride with Hydrophilic Interlayer or Macromolecular Additive by in-situ FT-IR Spectroscopy

2020 ◽  
Author(s):  
Xi Yang
Keyword(s):  
Aqueous Solution ◽  
Ir Spectroscopy ◽  
Reaction Rate ◽  
Interfacial Polymerization ◽  
Reaction Rates ◽  
Water Permeation ◽  
Ft Ir ◽  
Trimesoyl Chloride ◽  
Ft Ir Spectroscopy

The interfacial polymerization (IP) of piperazine (PIP) and trimesoyl chloride (TMC) has been extensively utilized to synthesize nanofiltration (NF) membranes. However, it is still a huge challenge to monitor the IP reaction, because of the fast reaction rate and the formed ultra-thin film. Herein, two effective strategies were applied to reduce the IP reaction rate: (1) the introduction of hydrophilic interlayers between the porous substrate and the formed polyamide layer, and (2) the addition of macromolecular additives in the aqueous solution of PIP. As a result, in situ Fourier transform infrared (FT-IR) spectroscopy was firstly used to monitor the IP reaction of PIP/TMC with hydrophilic interlayers or macromolecular additives in the aqueous solution of PIP. Moreover, the formed polyamide layer growth on the substrate was studied in a real-time manner. The in situ FTIR experimental results confirmed that the IP reaction rates were effectively suppressed and that the formed polyamide thickness was reduced from 138 &plusmn; 24 nm to 46 &plusmn; 2 nm according to TEM observation. Furthermore, an optimized NF membrane with excellent performance was consequently obtained, which included boosted water permeation of about 141&ndash;238 (L/m2&middot;h&middot;MPa) and superior salt rejection of Na2SO4 &gt; 98.4%.

Pitfalls and benefits of in situ and operando diffuse reflectance FT-IR spectroscopy (DRIFTS) applied to catalytic reactions

2016 ◽  
Vol 1 (2) ◽  
pp. 134-141 ◽  
Author(s):  
F. C. Meunier
Keyword(s):  
Ir Spectroscopy ◽  
Diffuse Reflectance ◽  
Catalytic Reactions ◽  
Ft Ir ◽  
Ft Ir Spectroscopy

The procedures and conditions that need to be fulfilled to be able to carry out appropriate in situ and operando diffuse reflectance FT-IR (DRIFTS) analyses are discussed.

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