Thermodynamic parameters of urethane formation reactions and concomitant processes

Samuilov, A. Ya.; Zenitova, L. A.; Bakirova, I. N.; Samuilov, Ya. D.

doi:10.1134/s1070427208080193

Cited by 4 publications

(2 citation statements)

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“…29 Thus, if net bond formation is observed, it must occur through the thermal quenching described above. Fourth, given reasonable estimations for the enthalpic (À132 kJ mol À1 ) and entropic (À188 J mol À1 ) changes associated with urethane formation, 30 the equilibrium for this reaction should lie far to the reactants at the extreme temperatures (>800 K) known to be obtained under our photothermal conditions (K 800 K z 7 Â 10 À2 M À1 ). 4 Thus, signicant progress of the reaction can also only be ascribed to trapping of transiently formed products during thermal quenchingrather than simple biasing of the equilibrium at high temperatures.…”

Section: Resultsmentioning

confidence: 89%

Billion-fold rate enhancement of urethane polymerization via the photothermal effect of plasmonic gold nanoparticles

Haas

Lear

2015

Chem. Sci.

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Section: Resultsmentioning

confidence: 89%

Billion-fold rate enhancement of urethane polymerization via the photothermal effect of plasmonic gold nanoparticles

Haas

Lear

2015

Chem. Sci.

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“…Equation provides a thermodynamic estimate of temperature. Reasonable estimates for the standard enthalpy and entropy of reaction for urethane formation are −132 kJ/mol and −188 J/(mol K), respectively . Using the percent completion to calculate an effective K EQ for condition 4, the thermodynamic estimate of temperature is 683 ± 28 K. The kinetic and thermodynamic estimates of the temperature under photothermal heating are summarized in Table .…”

Section: Discussionmentioning

confidence: 99%

Controlled Rapid Formation of Polyurethane at 700 K: Thermodynamic and Kinetic Consequences of Extreme Photothermal Heating

Burns

Lear

2019

J. Phys. Chem. C

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The photothermal effect of nanoparticles has proven to be an effective means of substantially increasing the rate of chemical transformations, by factors of up to 10 9 . For thermally activated processes, such a large increase in rate implies a corresponding increase in temperature large enough that it would be expected to affect the steady-state concentrations of products and reactants. We test this hypothesis by following the exothermic reaction between hexamethylene diisocyanate and poly-bis(triethylol) heptanedioate to produce a cross-linked polyurethane under both ambient and photothermal conditions. We demonstrate that the photothermal effect increases the reaction rate by a factor of 7.4 × 10 6 and decreases the effective equilibrium constant by a factor of at least 3 × 10 4 . These two changes provide kinetic and thermodynamic temperature estimates of 732 ± 21 and 683 ± 28 K, respectively. Remarkably, though both estimates of temperature are extreme, the chemical species produced under photothermal heating are the same as produced under ambient conditions.

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Polyurethanes based on anionic macroinitiators, aromatic isocyanates, and 4,4′-dihydroxy-2,2-diphenylpropane

et al. 2014

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Thermodynamic parameters of urethane formation reactions and concomitant processes

Cited by 4 publications

References 20 publications

Billion-fold rate enhancement of urethane polymerization via the photothermal effect of plasmonic gold nanoparticles

Billion-fold rate enhancement of urethane polymerization via the photothermal effect of plasmonic gold nanoparticles

Controlled Rapid Formation of Polyurethane at 700 K: Thermodynamic and Kinetic Consequences of Extreme Photothermal Heating

Polyurethanes based on anionic macroinitiators, aromatic isocyanates, and 4,4′-dihydroxy-2,2-diphenylpropane

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