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Your search keyword '"Schulz, Peter S."' showing total 211 results
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211 results on '"Schulz, Peter S."'

21. Synthesis of the zeolitic imidazolate framework ZIF-4 from the ionic liquid 1-butyl-3-methylimidazolium imidazolate.

Author

Hovestadt, Maximilian, Schwegler, Johannes, Schulz, Peter S., and Hartmann, Martin

Subjects
IMIDAZOLES, IONIC liquids, X-ray diffraction, PARTICLE size determination, ZEOLITES, CHEMICAL synthesis, ELECTROCHEMICAL research
Abstract

A new synthesis route for the zeolitic imidazolate framework ZIF-4 using imidazolium imidazolate is reported. Additionally, the ionic liquid-derived material is compared to conventional ZIF-4 with respect to the powder X-ray diffraction pattern pattern, nitrogen uptake, particle size, and separation potential for olefin/paraffin gas mixtures. Higher synthesis yields were obtained, and the different particle size affected the performance in the separation of ethane and ethylene. [ABSTRACT FROM AUTHOR]

Published
2018
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23. Influence of Carboxylate Anions on Phase Behavior of Choline Ionic Liquid Mixtures

Author

Elhi, Fred, Gantman, Mikhail, Nurk, Gunnar, Schulz, Peter S., Aabloo, Alvo, and Põhako-Esko, Kaija

Subjects
choline, eutectic mixture, differential scanning calorimetry, ionic liquid, phase diagram
Abstract

Mixing ionic liquids is a suitable strategy to tailor properties, e.g., to reduce melting points. The present study aims to widen the application range of low-toxic choline-based ionic liquids by studying eight binary phase diagrams of six different choline carboxylates. Five of them show eutectic points with melting points dropping by 13 to 45°C. The eutectic mixtures of choline acetate and choline 2-methylbutarate were found to melt at 45°C, which represents a remarkable melting point depression compared to the pure compounds with melting points of 81 (choline acetate) and 90°C (choline 2-methylbutarate), respectively. Besides melting points, the thermal stabilities of the choline salt mixtures were investigated to define the thermal operation range for potential practical applications of these mixtures. Typical decomposition temperatures were found between 165 and 207°C, with choline lactate exhibiting the highest thermal stability.

Published
2020

24. UiO‐66 and hcp UiO‐66 Catalysts Synthesized from Ionic Liquids as Linker Precursors

Author

Ermer, Matthias, Mehler, Julian, Rosenberger, Björn, Fischer, Marcus, Schulz, Peter S., and Hartmann, Martin

Subjects
ionic liquids, citronellal cyclization, lcsh:Chemistry, Full Paper, lcsh:QD1-999, UiO-66, US damping, ddc:540, Full Papers, metal-organic frameworks
Abstract

Using ionic liquids (ILs) as linker precursors, the well‐known metal‐organic framework (MOF) UiO‐66 (Universitetet i Oslo) and the recently reported MOF hcp UiO‐66 (hexagonal closed packed) have been successfully synthesized and characterized. The advantage of the applied novel synthesis approach is an economically and environmentally benign work‐up procedure, due to the better solubility of the IL. Additionally, the reactivity of the terephthalate anions is increased compared to terephthalic acid, resulting in faster MOF formation with an increased amount of defects in the MOF structure. In order to explore to the influence of defects on the catalytic performance, the cyclisation of citronellal to isopulegol was employed as test reaction. The activity of hcp UiO‐66 and fcc UiO‐66 (face centered cubic) is improved compared to other MOF or zeolite based catalysts, while the selectivity is similar., The use of ionic liquids as linker precursor for the synthesis of the metal‐organic frameworks hcp and fcc UiO‐66 results in faster crystallization thereby reducing synthesis time and energy consumed. Furthermore, the catalytic activity of the MOFs in the cyclization of citronellal to isopulegol is increased due to defects within the frameworks while the selectivity is not affected.

Published
2020

33. UiO‐66 and hcp UiO‐66 Catalysts Synthesized from Ionic Liquids as Linker Precursors.

Author

Ermer, Matthias, Mehler, Julian, Rosenberger, Björn, Fischer, Marcus, Schulz, Peter S., and Hartmann, Martin

Subjects
IONIC liquids, ZEOLITE catalysts, METAL-organic frameworks, TEREPHTHALIC acid, CATALYSTS
Abstract

Using ionic liquids (ILs) as linker precursors, the well‐known metal‐organic framework (MOF) UiO‐66 (Universitetet i Oslo) and the recently reported MOF hcp UiO‐66 (hexagonal closed packed) have been successfully synthesized and characterized. The advantage of the applied novel synthesis approach is an economically and environmentally benign work‐up procedure, due to the better solubility of the IL. Additionally, the reactivity of the terephthalate anions is increased compared to terephthalic acid, resulting in faster MOF formation with an increased amount of defects in the MOF structure. In order to explore to the influence of defects on the catalytic performance, the cyclisation of citronellal to isopulegol was employed as test reaction. The activity of hcp UiO‐66 and fcc UiO‐66 (face centered cubic) is improved compared to other MOF or zeolite based catalysts, while the selectivity is similar. [ABSTRACT FROM AUTHOR]

Published
2021
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36. Thermophysical properties of homologous tetracyanoborate-based ionic liquids using experiments and molecular dynamics simulations

Author

German Research Foundation, European Commission, Ministerio de Economía y Competitividad (España), Koller, Thomas M., Ramos, Javier, Schulz, Peter S., Economou Ioannis G., Rausch, Michael H., Fröba, Andreas P., German Research Foundation, European Commission, Ministerio de Economía y Competitividad (España), Koller, Thomas M., Ramos, Javier, Schulz, Peter S., Economou Ioannis G., Rausch, Michael H., and Fröba, Andreas P.

Abstract

Thermophysical properties of low-viscosity ionic liquids (ILs) based on the tetracyanoborate ([B(CN)]) anion carrying a homologous series of 1-alkyl-3-methylimidazolium ([AMIM]) cations [EMIM] (ethyl), [BMIM] (butyl), [HMIM] (hexyl), [OMIM] (octyl), and [DMIM] (decyl) were investigated by experimental methods and molecular dynamics (MD) simulations at atmospheric pressure and various temperatures. Spectroscopic methods based on nuclear magnetic resonance and surface light scattering were applied to measure the ion self-diffusion coefficients and dynamic viscosity, respectively. In terms of MD simulations, a nonpolarizable molecular model for [EMIM][B(CN)] developed by optimization to experimental data was transferred to the other homologous ILs. For the appropriate description of the inter- and intramolecular interactions, precise and approximate force fields (FFs) were tested regarding their transferability within the homologous IL series, aiming at reducing the computational effort in molecular simulations. It is shown that at comparable simulated and experimental densities, the calculated and measured data for viscosity and self-diffusion coefficients of the ILs agree well mostly within combined uncertainties, but deviate stronger for longer-chained ILs using an overly coarse FF model. For the [B(CN)]-based ILs studied, a comparison with literature data, the influence of varying alkyl chain length in the cation on their structural and thermophysical properties, and a correlation between self-diffusivity and viscosity are discussed.

Published
2017

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