Gas-phase elimination reaction of ethyl (5-cyanomethyl-1,3,4- thiadiazol-2-yl)carbamate: A computational study

Ederley Vélez, Pablo Ruíz, Jairo Quijano, Rafael Notario

Resultado de la investigación: Contribución a una revistaArtículoInvestigaciónrevisión exhaustiva

Resumen

© 2015 Wiley Periodicals, Inc. The gas-phase elimination reaction of ethyl (5-cyanomethyl-1,3,4-thiadiazol-2-yl)carbamate has been studied computationally at the MP2/6–31++G(2d,p) level of theory. The values of the activation parameters and rate constants for the thermal decomposition were evaluated over a temperature range from 405.0 to 458.0 K. The temperature dependence of the rate constants was used to deduce the modified Arrhenius expression: log k405–458 K = (9.01 ± 0.49) + (1.32 ± 0.16) log T – (6946 ± 30) 1/T, which is in good agreement with the expression obtained from experimental data. The results confirm that the mechanism is a cis-concerted elimination that occurs in two steps: The first one corresponds to the formation of ethylene and an intermediate, 5-(cyanomethyl)-1,3,4-thiadiazol-2-yl-carbamic acid, via a six-membered cyclic transition state, and the second one is the decarboxylation of this intermediate via a four-membered cyclic transition step, leading to carbon dioxide and the corresponding 1,3,4-thiadiazole derivative (5-amino-1,3,4-thiadiazole-2-acetonitrile). The connectivity of transition states with their respective minima was verified through intrinsic reaction coordinate calculations, and the progress of the reaction was followed by means of Wiberg bond indices, resulting that both transition states have an “early” character, nearer to the reactants than to the products.
Idioma originalInglés estadounidense
Páginas (desde-hasta)23-31
Número de páginas9
PublicaciónInternational Journal of Chemical Kinetics
DOI
EstadoPublicada - 23 nov 2015

Huella dactilar

Carbamates
2-amino-1,3,4-thiadiazole
elimination
Rate constants
Gases
vapor phases
Decarboxylation
Temperature
Carbon Dioxide
Pyrolysis
Hot Temperature
Chemical activation
Derivatives
decarboxylation
acetonitrile
thermal decomposition
carbon dioxide
ethylene
activation
temperature dependence

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title = "Gas-phase elimination reaction of ethyl (5-cyanomethyl-1,3,4- thiadiazol-2-yl)carbamate: A computational study",
abstract = "{\circledC} 2015 Wiley Periodicals, Inc. The gas-phase elimination reaction of ethyl (5-cyanomethyl-1,3,4-thiadiazol-2-yl)carbamate has been studied computationally at the MP2/6–31++G(2d,p) level of theory. The values of the activation parameters and rate constants for the thermal decomposition were evaluated over a temperature range from 405.0 to 458.0 K. The temperature dependence of the rate constants was used to deduce the modified Arrhenius expression: log k405–458 K = (9.01 ± 0.49) + (1.32 ± 0.16) log T – (6946 ± 30) 1/T, which is in good agreement with the expression obtained from experimental data. The results confirm that the mechanism is a cis-concerted elimination that occurs in two steps: The first one corresponds to the formation of ethylene and an intermediate, 5-(cyanomethyl)-1,3,4-thiadiazol-2-yl-carbamic acid, via a six-membered cyclic transition state, and the second one is the decarboxylation of this intermediate via a four-membered cyclic transition step, leading to carbon dioxide and the corresponding 1,3,4-thiadiazole derivative (5-amino-1,3,4-thiadiazole-2-acetonitrile). The connectivity of transition states with their respective minima was verified through intrinsic reaction coordinate calculations, and the progress of the reaction was followed by means of Wiberg bond indices, resulting that both transition states have an “early” character, nearer to the reactants than to the products.",
author = "Ederley V{\'e}lez and Pablo Ru{\'i}z and Jairo Quijano and Rafael Notario",
year = "2015",
month = "11",
day = "23",
doi = "10.1002/kin.20967",
language = "American English",
pages = "23--31",
journal = "International Journal of Chemical Kinetics",
issn = "0538-8066",
publisher = "John Wiley and Sons Inc.",

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Gas-phase elimination reaction of ethyl (5-cyanomethyl-1,3,4- thiadiazol-2-yl)carbamate: A computational study. / Vélez, Ederley; Ruíz, Pablo; Quijano, Jairo; Notario, Rafael.

En: International Journal of Chemical Kinetics, 23.11.2015, p. 23-31.

Resultado de la investigación: Contribución a una revistaArtículoInvestigaciónrevisión exhaustiva

TY - JOUR

T1 - Gas-phase elimination reaction of ethyl (5-cyanomethyl-1,3,4- thiadiazol-2-yl)carbamate: A computational study

AU - Vélez, Ederley

AU - Ruíz, Pablo

AU - Quijano, Jairo

AU - Notario, Rafael

PY - 2015/11/23

Y1 - 2015/11/23

N2 - © 2015 Wiley Periodicals, Inc. The gas-phase elimination reaction of ethyl (5-cyanomethyl-1,3,4-thiadiazol-2-yl)carbamate has been studied computationally at the MP2/6–31++G(2d,p) level of theory. The values of the activation parameters and rate constants for the thermal decomposition were evaluated over a temperature range from 405.0 to 458.0 K. The temperature dependence of the rate constants was used to deduce the modified Arrhenius expression: log k405–458 K = (9.01 ± 0.49) + (1.32 ± 0.16) log T – (6946 ± 30) 1/T, which is in good agreement with the expression obtained from experimental data. The results confirm that the mechanism is a cis-concerted elimination that occurs in two steps: The first one corresponds to the formation of ethylene and an intermediate, 5-(cyanomethyl)-1,3,4-thiadiazol-2-yl-carbamic acid, via a six-membered cyclic transition state, and the second one is the decarboxylation of this intermediate via a four-membered cyclic transition step, leading to carbon dioxide and the corresponding 1,3,4-thiadiazole derivative (5-amino-1,3,4-thiadiazole-2-acetonitrile). The connectivity of transition states with their respective minima was verified through intrinsic reaction coordinate calculations, and the progress of the reaction was followed by means of Wiberg bond indices, resulting that both transition states have an “early” character, nearer to the reactants than to the products.

AB - © 2015 Wiley Periodicals, Inc. The gas-phase elimination reaction of ethyl (5-cyanomethyl-1,3,4-thiadiazol-2-yl)carbamate has been studied computationally at the MP2/6–31++G(2d,p) level of theory. The values of the activation parameters and rate constants for the thermal decomposition were evaluated over a temperature range from 405.0 to 458.0 K. The temperature dependence of the rate constants was used to deduce the modified Arrhenius expression: log k405–458 K = (9.01 ± 0.49) + (1.32 ± 0.16) log T – (6946 ± 30) 1/T, which is in good agreement with the expression obtained from experimental data. The results confirm that the mechanism is a cis-concerted elimination that occurs in two steps: The first one corresponds to the formation of ethylene and an intermediate, 5-(cyanomethyl)-1,3,4-thiadiazol-2-yl-carbamic acid, via a six-membered cyclic transition state, and the second one is the decarboxylation of this intermediate via a four-membered cyclic transition step, leading to carbon dioxide and the corresponding 1,3,4-thiadiazole derivative (5-amino-1,3,4-thiadiazole-2-acetonitrile). The connectivity of transition states with their respective minima was verified through intrinsic reaction coordinate calculations, and the progress of the reaction was followed by means of Wiberg bond indices, resulting that both transition states have an “early” character, nearer to the reactants than to the products.

U2 - 10.1002/kin.20967

DO - 10.1002/kin.20967

M3 - Article

SP - 23

EP - 31

JO - International Journal of Chemical Kinetics

JF - International Journal of Chemical Kinetics

SN - 0538-8066

ER -