| |
|
|
| Registros recuperados : 14 | |
| 1. |  | GARCIA, R. H. S.; COLNAGO, L. A. Desenvolvimento de sequência de pulso em RMN-DT para caracterização de sementes de soja In: JORNADA CIENTÍFICA - EMBRAPA SÃO CARLOS, 8., 2016, São Carlos, SP. Anais... São Carlos: Embrapa Instrumentação: Embrapa Pecuária Sudeste, 2016. p.89. Editores técnicos: Wilson Tadeu Lopes da Silva, José Manoel Marconcini, Maria Alice Martins, Lucimara Aparecida Forato, Paulino Ribeiro Villas Boas. (Embrapa Instrumentação. Documentos, 61).| Biblioteca(s): Embrapa Instrumentação. |
|    |
| 2. | | GARCIA, R. H. S.; COLNAGO, L. A. Utilização da RMN-DT no controle de qualidade de manteigas e margarinas. In: SIMPÓSIO NACIONAL DE INSTRUMENTAÇÃO AGROPECUÁRIA, 4., 2019, São Carlos, SP. Ciência, inovação e mercado: anais. São Carlos, SP: Embrapa Instrumentação, 2019. Editores: Paulino Ribeiro Villas-Boas, Maria Alice Martins, Débora Marcondes Bastos Pereira Milori, Ladislau Martin Neto. SIAGRO 2019. 685-689| Biblioteca(s): Embrapa Instrumentação. |
| |
| 3. | | GARCIA, R. H. S.; COLNAGO, L. A.; TANNÚS, A. Desenvolvimento e aplicação de pulsos formatados para RMN-DT. In: SIMPÓSIO NACIONAL DE INSTRUMENTAÇÃO AGROPECUÁRIA, 2014, São Carlos, SP Anais do SIAGRO: ciência, inovação e mercado 2014. São Carlos, SP: Embrapa Instrumentação, 2014. p. 245-248. Editores: Carlos Manoel Pedro Vaz, Débora Marcondes Bastos Pereira Milori, Silvio Crestana.| Biblioteca(s): Embrapa Instrumentação. |
| |
| 8. | | SOUZA, D. G.; RESENDE, O.; PILON, L.; COLNAGO, L. A.; GARCIA, R. H. S.; ALMEIDA, A. B. Functional characterization of biofortified sweet potato flour dried at different temperatures. International Journal for Innovation Education and Research, v. 8, n.12, p. 167-182, 2020.| Biblioteca(s): Embrapa Hortaliças; Embrapa Instrumentação. |
| |
| 10. | | FACCHINATTO, W. M.; GARCIA, R. H. S.; SANTOS, D. M.; FIAMINGO, A.; FLORES, D. W. M.; CAMPANA-FILHO, S. P.; AZEVEDO, E. R.; COLNAGO, L. A. Fast-forward approach of time-domain NMR relaxometry for solid-state chemistry of chitosan. Carbohydrate Polymers, v. 256, 117576, 2021. 1 - 10| Biblioteca(s): Embrapa Instrumentação. |
|  |
| 11. | | MACHADO, G. O.; TEIXEIRA, G. G.; GARCIA, R. H. S.; MORAES, T. B.; BONA, E.; SANTOS, P. M.; COLNAGO, L. A. Non-invasive method to predict the composition of requeijão cremoso directly in commercial packages using time domain NMR relaxometry and chemometrics. Molecules, v. 27, a4434, 2022. 10 p.| Biblioteca(s): Embrapa Instrumentação. |
| |
| 12. | | BIANQUINI, T. S.; FLORENCIO, C.; GARCIA, R. H. S.; COLNAGO, L. A.; CECCATO-ANTONINI, S. R.; CARMO, M.; TELES, J.; FARINAS, C. S.; RIBEIRO, T. S. Time domain NMR spectroscopy as a fast method for probing the efficiency of biomass pretreatments for second generation ethanol production. Biomass and Bioenergy, v. 142, a. 105734, 2020.| Biblioteca(s): Embrapa Instrumentação. |
| |
| 13. | | SANTOS, Y. J. S.; CAMPOS, N. A.; BICCA, G. B.; SORA, G. T. S.; POLESI, L. F.; ALBERTE, T. M.; SANTOS, P. M.; GARCIA, R. H. S.; COLNAGO, L. A.; OLIVEIRA-FOLADOR. G. Non-destructive determination of the oil content in peach palm (Bactris gasipaes) flour using NMR and NIR spectroscopies. Food Science and Technology, v. 43, e112322, 2023. 1 - 8| Biblioteca(s): Embrapa Instrumentação. |
| |
| 14. | | SALVADOR, M. V.; KOCK, F. V. C.; SANTOS, I. L.; PAULINO, J. F. C.; ALMEIDA, C. P. de; GARCIA, R. H. S.; BENCHIMOL-REIS, L. L.; COLNAGO, L. A.; FERREIRA, A. G. Monitoring stimulated darkening from UV-C light on different bean genotypes by NMR spectroscopy. Molecules, v. 27, 2060, 2022. 10 p.| Biblioteca(s): Embrapa Instrumentação. |
| |
| Registros recuperados : 14 | |
|
|
|
Registro Completo
|
Biblioteca(s): |
Embrapa Instrumentação. |
|
Data corrente: |
30/03/2022 |
|
Data da última atualização: |
23/01/2024 |
|
Tipo da produção científica: |
Artigo em Periódico Indexado |
|
Circulação/Nível: |
B - 1 |
|
Autoria: |
GARCIA, R. H. S.; FILGUEIRAS, J. G.; COLNAGO, L. A.; AZEVEDO, E. R. |
|
Afiliação: |
LUIZ ALBERTO COLNAGO, CNPDIA. |
|
Título: |
Real-Time monitoring polymerization reactions using dipolar echoes in 1H time domain NMR at a low magnetic field. |
|
Ano de publicação: |
2022 |
|
Fonte/Imprenta: |
Molecules, v. 27, 566, 2022. |
|
Páginas: |
14 p. |
|
DOI: |
https://doi.org/10.3390/molecules27020566 |
|
Idioma: |
Inglês |
|
Conteúdo: |
1H time domain nuclear magnetic resonance (1H TD-NMR) at a low magnetic field becomes a powerful technique for the structure and dynamics characterization of soft organic materials. This relies mostly on the method sensitivity to the 1H-1H magnetic dipolar couplings, which depend on the molecular orientation with respect to the applied magnetic field. On the other hand, the good sensitivity of the 1H detection makes it possible to monitor real time processes that modify the dipolar coupling as a result of changes in the molecular mobility. In this regard, the so-called dipolar echoes technique can increase the sensitivity and accuracy of the real-time monitoring. In this article we evaluate the performance of commonly used 1H TD-NMR dipolar echo methods for probing polymerization reactions. As a proof of principle, we monitor the cure of a commercial epoxy resin,using techniques such as mixed-Magic Sandwich Echo (MSE), Rhim Kessemeier—Radiofrequency Optimized Solid Echo (RK-ROSE) and Dipolar Filtered Magic Sandwich Echo (DF-MSE). Applying a reaction kinetic model that supposes simultaneous autocatalytic and noncatalytic reaction pathways,we show the analysis to obtain the rate and activation energy for the epoxy curing reaction using the NMR data. The results obtained using the different NMR methods are in good agreement among them and also results reported in the literature for similar samples. This demonstrates that any of these dipolar echo pulse sequences can be efficiently used for monitoring and characterizing this type of reaction. Nonetheless, the DF-MSE method showed intrinsic advantages, such as easier data handling and processing, and seems to be the method of choice for monitoring this type of reaction.In general, the procedure is suitable for characterizing reactions involving the formation of solidproducts from liquid reagents, with some adaptations concerning the reaction model. Menos1H time domain nuclear magnetic resonance (1H TD-NMR) at a low magnetic field becomes a powerful technique for the structure and dynamics characterization of soft organic materials. This relies mostly on the method sensitivity to the 1H-1H magnetic dipolar couplings, which depend on the molecular orientation with respect to the applied magnetic field. On the other hand, the good sensitivity of the 1H detection makes it possible to monitor real time processes that modify the dipolar coupling as a result of changes in the molecular mobility. In this regard, the so-called dipolar echoes technique can increase the sensitivity and accuracy of the real-time monitoring. In this article we evaluate the performance of commonly used 1H TD-NMR dipolar echo methods for probing polymerization reactions. As a proof of principle, we monitor the cure of a commercial epoxy resin,using techniques such as mixed-Magic Sandwich Echo (MSE), Rhim Kessemeier—Radiofrequency Optimized Solid Echo (RK-ROSE) and Dipolar Filtered Magic Sandwich Echo (DF-MSE). Applying a reaction kinetic model that supposes simultaneous autocatalytic and noncatalytic reaction pathways,we show the analysis to obtain the rate and activation energy for the epoxy curing reaction using the NMR data. The results obtained using the different NMR methods are in good agreement among them and also results reported in the literature for similar samples. This demonstrates that any of these dipolar echo pulse sequences can be efficien... Mostrar Tudo |
|
Palavras-Chave: |
Autocatalytic reaction; Dipolar echoes; Epoxy resin; Ime-domain NMR; Polymerization reaction. |
|
Categoria do assunto: |
-- |
|
URL: |
https://ainfo.cnptia.embrapa.br/digital/bitstream/item/233135/1/P-Real-Time-Monitoring-Polymerization-Reactions-Using-Dipolar.pdf
|
|
Marc: |
LEADER 02669naa a2200241 a 4500
001 2141628
005 2024-01-23
008 2022 bl uuuu u00u1 u #d
024 7 $ahttps://doi.org/10.3390/molecules27020566$2DOI
100 1 $aGARCIA, R. H. S.
245 $aReal-Time monitoring polymerization reactions using dipolar echoes in 1H time domain NMR at a low magnetic field.$h[electronic resource]
260 $c2022
300 $a14 p.
520 $a1H time domain nuclear magnetic resonance (1H TD-NMR) at a low magnetic field becomes a powerful technique for the structure and dynamics characterization of soft organic materials. This relies mostly on the method sensitivity to the 1H-1H magnetic dipolar couplings, which depend on the molecular orientation with respect to the applied magnetic field. On the other hand, the good sensitivity of the 1H detection makes it possible to monitor real time processes that modify the dipolar coupling as a result of changes in the molecular mobility. In this regard, the so-called dipolar echoes technique can increase the sensitivity and accuracy of the real-time monitoring. In this article we evaluate the performance of commonly used 1H TD-NMR dipolar echo methods for probing polymerization reactions. As a proof of principle, we monitor the cure of a commercial epoxy resin,using techniques such as mixed-Magic Sandwich Echo (MSE), Rhim Kessemeier—Radiofrequency Optimized Solid Echo (RK-ROSE) and Dipolar Filtered Magic Sandwich Echo (DF-MSE). Applying a reaction kinetic model that supposes simultaneous autocatalytic and noncatalytic reaction pathways,we show the analysis to obtain the rate and activation energy for the epoxy curing reaction using the NMR data. The results obtained using the different NMR methods are in good agreement among them and also results reported in the literature for similar samples. This demonstrates that any of these dipolar echo pulse sequences can be efficiently used for monitoring and characterizing this type of reaction. Nonetheless, the DF-MSE method showed intrinsic advantages, such as easier data handling and processing, and seems to be the method of choice for monitoring this type of reaction.In general, the procedure is suitable for characterizing reactions involving the formation of solidproducts from liquid reagents, with some adaptations concerning the reaction model.
653 $aAutocatalytic reaction
653 $aDipolar echoes
653 $aEpoxy resin
653 $aIme-domain NMR
653 $aPolymerization reaction
700 1 $aFILGUEIRAS, J. G.
700 1 $aCOLNAGO, L. A.
700 1 $aAZEVEDO, E. R.
773 $tMolecules$gv. 27, 566, 2022.
Download
Esconder MarcMostrar Marc Completo |
|
Registro original: |
Embrapa Instrumentação (CNPDIA) |
|
|
Biblioteca |
ID |
Origem |
Tipo/Formato |
Classificação |
Cutter |
Registro |
Volume |
Status |
Fechar
|
| Nenhum registro encontrado para a expressão de busca informada. |
|
|
