Determination of Gas Transport Coefficients of Mixed Gases in 6FDA-TMPDA Polyimide by NMR Spectroscopy

2017 ◽  
Vol 50 (9) ◽  
pp. 3590-3597 ◽  
Author(s):  
Leoncio Garrido ◽  
Carolina García ◽  
Mar López-González ◽  
Bibiana Comesaña-Gándara ◽  
Ángel E. Lozano ◽  
...  
Keyword(s):  
Nmr Spectroscopy ◽  
Gas Transport ◽  
Transport Coefficients ◽  
Mixed Gases

Determination of gas transport coefficients in ceramic bodies during thermolysis of organic additives

1996 ◽  
Vol 41 (3) ◽  
pp. 116-128 ◽  
Author(s):  
J. H. Song ◽  
J. R. G. Evans ◽  
M. J. Edirisinghe ◽  
E. H. Twizell
Keyword(s):  
Gas Transport ◽  
Transport Coefficients ◽  
Organic Additives

Quantitative Determination of Krill Oil Composition by ATR-FTIR, NIR, and 31P NMR Spectroscopy

2020 ◽  
Author(s):  
Ashraf Ismail ◽  
Sanaz Molaye Moghaddam ◽  
Jean-Pierre MetabanzoulouSarya Aziz ◽  
Jacqueline Sedman ◽  
Mazen Bahadi
Keyword(s):  
Nmr Spectroscopy ◽  
Quantitative Determination ◽  
31P Nmr ◽  
31P Nmr Spectroscopy ◽  
Krill Oil ◽  
Oil Composition

Determination of alcohols in mixtures by 19F NMR spectroscopy using hexefluoroacetone reagent

1982 ◽  
Vol 47 (7) ◽  
pp. 1973-1978 ◽  
Author(s):  
Jiří Karhan ◽  
Zbyněk Ksandr ◽  
Jiřina Vlková ◽  
Věra Špatná
Keyword(s):  
Standard Deviation ◽  
Nmr Spectroscopy ◽  
Standard Method ◽  
Internal Standard ◽  
Internal Standard Method ◽  
Concentration Region ◽  
Experimental Conditions ◽  
Curve Method ◽  
Sample Preparation Procedure

The determination of alcohols by 19F NMR spectroscopy making use of their reaction with hexafluoroacetone giving rise to hemiacetals was studied on butanols. The calibration curve method and the internal standard method were used and the results were mutually compared. The effects of some experimental conditions, viz. the sample preparation procedure, concentration, spectrometer setting, and electronic integration, were investigated; the conditions, particularly the concentrations, proved to have a statistically significant effect on the results of determination. For the internal standard method, the standard deviation was 0.061 in the concentration region 0.032-0.74 mol l-1. The method was applied to a determination of alcohols in the distillation residue from an oxo synthesis.

Determination of Tautomeric Preference of Fenobam in Solution by High Resolution NMR Spectroscopy

2020 ◽  
Author(s):  
Xuming Sha ◽  
Shaodong Chen ◽  
Xiaojing Zheng ◽  
Xin Ye ◽  
Hailu Zhang ◽  
...  
Keyword(s):  
Nmr Spectroscopy ◽  
High Resolution ◽  
High Resolution Nmr

scholarly journals A Molecular Simulation Study of Silica/Polysulfone Mixed Matrix Membrane for Mixed Gas Separation

Polymers ◽  
2021 ◽  
Vol 13 (13) ◽  
pp. 2199
Author(s):  
Khadija Asif ◽  
Serene Sow Mun Lock ◽  
Syed Ali Ammar Taqvi ◽  
Norwahyu Jusoh ◽  
Chung Loong Yiin ◽  
...  
Keyword(s):  
Transport Properties ◽  
Molecular Simulation ◽  
Gas Separation ◽  
Membrane Separation ◽  
Gas Transport ◽  
Mixed Matrix ◽  
Mixed Gas ◽  
Gas Transport Properties ◽  
Simulation Results ◽  
Mixed Gases

Polysulfone-based mixed matrix membranes (MMMs) incorporated with silica nanoparticles are a new generation material under ongoing research and development for gas separation. However, the attributes of a better-performing MMM cannot be precisely studied under experimental conditions. Thus, it requires an atomistic scale study to elucidate the separation performance of silica/polysulfone MMMs. As most of the research work and empirical models for gas transport properties have been limited to pure gas, a computational framework for molecular simulation is required to study the mixed gas transport properties in silica/polysulfone MMMs to reflect real membrane separation. In this work, Monte Carlo (MC) and molecular dynamics (MD) simulations were employed to study the solubility and diffusivity of CO2/CH4 with varying gas concentrations (i.e., 30% CO2/CH4, 50% CO2/CH4, and 70% CO2/CH4) and silica content (i.e., 15–30 wt.%). The accuracy of the simulated structures was validated with published literature, followed by the study of the gas transport properties at 308.15 K and 1 atm. Simulation results concluded an increase in the free volume with an increasing weight percentage of silica. It was also found that pure gas consistently exhibited higher gas transport properties when compared to mixed gas conditions. The results also showed a competitive gas transport performance for mixed gases, which is more apparent when CO2 increases. In this context, an increment in the permeation was observed for mixed gas with increasing gas concentrations (i.e., 70% CO2/CH4 > 50% CO2/CH4 > 30% CO2/CH4). The diffusivity, solubility, and permeability of the mixed gases were consistently increasing until 25 wt.%, followed by a decrease for 30 wt.% of silica. An empirical model based on a parallel resistance approach was developed by incorporating mathematical formulations for solubility and permeability. The model results were compared with simulation results to quantify the effect of mixed gas transport, which showed an 18% and 15% percentage error for the permeability and solubility, respectively, in comparison to the simulation data. This study provides a basis for future understanding of MMMs using molecular simulations and modeling techniques for mixed gas conditions that demonstrate real membrane separation.

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