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Publications (10 of 93) Show all publications
Sophonrat, N., Sandström, L., Svanberg, R., Han, T., Dvinskikh, S., Lousada, C. M. & Yang, W. (2019). Ex Situ Catalytic Pyrolysis of a Mixture of Polyvinyl Chloride and Cellulose Using Calcium Oxide for HCl Adsorption and Catalytic Reforming of the Pyrolysis Products. Industrial & Engineering Chemistry Research, 58(31), 13960-13970
Open this publication in new window or tab >>Ex Situ Catalytic Pyrolysis of a Mixture of Polyvinyl Chloride and Cellulose Using Calcium Oxide for HCl Adsorption and Catalytic Reforming of the Pyrolysis Products
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2019 (English)In: Industrial & Engineering Chemistry Research, ISSN 0888-5885, E-ISSN 1520-5045, Vol. 58, no 31, p. 13960-13970Article in journal (Refereed) Published
Abstract [en]

In the context of chemical recycling of mixed plastics and paper, multitemperature step pyrolysis has shown good potential for the separation of oxygenated products from hydrocarbons. Here, we report results of an investigation of the first pyrolysis step at low temperature, which involves the dehydrochlorination of polyvinyl chloride (PVC) and the pyrolysis of cellulose, the main component of paper. Calcium oxide (CaO), selected for its chloride adsorption ability and its catalytic activity on biooil deoxygenation, was used for upgrading the downstream products from the pyrolysis. Additionally, we studied the performance of CaO for the simultaneous adsorption of HCl and for reforming cellulose pyrolysates in the temperature range of 300-600 degrees C with feedstock to CaO ratios of 1:0.2, 1:0.4, and 1:1. It was found that the suitable catalytic temperature for HCl and acetic acid adsorption is lower than 400 degrees C. This is due to the desorption of HCl from CaCl2 and Ca(OH)Cl in the presence of water and CO2 at 400 degrees C and higher. A larger amount of CaO resulted in a more efficient reduction of acids and the organic liquids were found to have lower amounts of oxygen. A comparison between the cases of neat and mixed feedstock showed that pyrolysis of mixed feedstock produced more water, H-2, CO, and polycyclic aromatic hydrocarbons (PAHs) when compared to the case of neat materials over CaO.

Place, publisher, year, edition, pages
American Chemical Society (ACS), 2019
National Category
Other Chemical Engineering
Identifiers
urn:nbn:se:kth:diva-257448 (URN)10.1021/acs.iecr.9b02299 (DOI)000480496100016 ()2-s2.0-85071301059 (Scopus ID)
Note

QC 20190830

Available from: 2019-08-30 Created: 2019-08-30 Last updated: 2019-09-04Bibliographically approved
Gradisek, A., Cifelli, M., Wojcik, M., Apih, T., Dvinskikh, S., Gorecka, E. & Domenici, V. (2019). Study of Liquid Crystals Showing Two Isotropic Phases by H-1 NMR Diffusometry and H-1 NMR Relaxometry. CRYSTALS, 9(3), Article ID 178.
Open this publication in new window or tab >>Study of Liquid Crystals Showing Two Isotropic Phases by H-1 NMR Diffusometry and H-1 NMR Relaxometry
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2019 (English)In: CRYSTALS, Vol. 9, no 3, article id 178Article in journal (Refereed) Published
Abstract [en]

In this work, we report a study of two thermotropic liquid crystalline samples showing a not common mesophase behavior. The samples, namely a di-benzyloxy biphenyl derivative labelled 9/2 RS/RS, and a bimesogenic liquid crystal labelled L1, show a direct transition between two isotropic phases followed, at lower temperatures, by the optically isotropic, 3D structured, cubic phase. These systems have been investigated by means of H-1 NMR diffusometry and H-1 NMR relaxometry in order to characterize their isotropic-isotropic'-cubic mesophase behavior, mainly on the dynamic point of view. In particular, the temperature trend of the self-diffusion coefficients measured for both samples allowed us to significantly distinguish between the two isotropic phases, while the temperature dependence of the H-1 spin-lattice relaxation time (T-1) did not show significant discontinuities at the isotropic-isotropic' phase transition. A preliminary analysis of the frequency-dependence of H-1 T-1 at different temperatures gives information about the main motional processes active in the isotropic mesophases.

Place, publisher, year, edition, pages
MDPI, 2019
Keywords
NMR, cubic phase, isotropic phase, self-diffusion, liquid crystals, relaxation time, dynamics, H-1 NMR
National Category
Physical Chemistry
Identifiers
urn:nbn:se:kth:diva-251345 (URN)10.3390/cryst9030178 (DOI)000464478100003 ()2-s2.0-85064653109 (Scopus ID)
Note

QC 20190521

Available from: 2019-05-21 Created: 2019-05-21 Last updated: 2019-05-23Bibliographically approved
Dvinskikh, S. (2018). Chapter 13: Characterization of Liquid-crystalline Materials by Separated Local Field Methods. In: New Developments in NMR: (pp. 391-423). Royal Society of Chemistry (15)
Open this publication in new window or tab >>Chapter 13: Characterization of Liquid-crystalline Materials by Separated Local Field Methods
2018 (English)In: New Developments in NMR, Royal Society of Chemistry, 2018, no 15, p. 391-423Chapter in book (Refereed)
Abstract [en]

A unique feature of liquid crystals is a high degree of molecular mobility combined with orientational and positional order. Solid-state NMR contributes to fundamental understanding of diverse molecular organizations and complex dynamic processes in these exciting materials. The focus of this chapter is on the development and application of advanced solid-state NMR methodologies for liquid crystal studies, with emphasis on techniques for measuring anisotropic spin couplings. The discussion centers on applications of separated dipolar local field NMR spectroscopy, which is used in an increasing number of directions in studies of novel liquid-crystalline materials for emerging technological applications.

Place, publisher, year, edition, pages
Royal Society of Chemistry, 2018
Keywords
deuterium, lipid, nanocomposite, proton, anisotropy, atom, chemical structure, comparative study, heating, heteronuclear dipolar nuclear magnetic resonance spectroscopy, lipid bilayer, lipid membrane, liquid crystal, magic angle spinning separated local field nuclear magnetic resonance spectroscopy, magnetic field, molecular dynamics, nuclear magnetic resonance spectroscopy, nuclear Overhauser effect, phase transition, proton encoded detected separated local field nuclear magnetic resonance spectroscopy, proton nuclear magnetic resonance, separated local field nuclear magnetic resonance spectroscopy, solid state
National Category
Physical Chemistry
Identifiers
urn:nbn:se:kth:diva-236437 (URN)10.1039/9781788010467-00391 (DOI)2-s2.0-85046947071 (Scopus ID)
Funder
Swedish Research Council
Note

QC 20181025

Available from: 2018-10-25 Created: 2018-10-25 Last updated: 2018-10-25Bibliographically approved
Jackalin, L., Kharkov, B. B., Komolkin, A. V. & Dvinskikh, S. (2018). Experimental strategies for 13C-15N dipolar NMR spectroscopy in liquid crystals at the natural isotopic abundance. Physical Chemistry, Chemical Physics - PCCP, 20(34), 22187-22196
Open this publication in new window or tab >>Experimental strategies for 13C-15N dipolar NMR spectroscopy in liquid crystals at the natural isotopic abundance
2018 (English)In: Physical Chemistry, Chemical Physics - PCCP, ISSN 1463-9076, E-ISSN 1463-9084, Vol. 20, no 34, p. 22187-22196Article in journal (Refereed) Published
Abstract [en]

Direct dipolar spin couplings are informative and sensitive probes for a wide range of dynamic processes and structural properties at atomic, molecular and supramolecular levels in liquid crystals and other anisotropic materials. Usually, heteronuclear 13C-1H dipolar couplings in liquid crystals with natural 13C abundance are measured. Recording 13C-15N NMR dipolar spectra in unlabeled materials is challenging because of the unfavorable combination of two rare isotopes. Here we design and compare various experimental strategies to measure short- and long-range heteronuclear 13C-15N dipolar couplings in liquid crystalline samples with high molecular orientational order. New techniques were developed to record 13C and 15N spectra of naturally occurring 13C-15N spin pairs with increased signal intensity and spectral resolution while suppressing the signals of the uncoupled isotopes. Highly resolved 13C-15N dipolar spectra were recorded within an experimental time of a few hours. Coupling constants in a broad range of 10-1000 Hz between spins separated by up to five chemical bonds and distances of up to 5 Å were measured. Because of their relatively low demands on radio-frequency power levels, the experiments were easy to implement using conventional high-resolution solution-state NMR hardware. Experimental data were compared to the results of density functional theory and molecular dynamics computational analyses. The presented experimental methods to characterize the dipolar couplings in unlabeled materials provide novel routes to investigate molecular structure and dynamics in mesophases.

Place, publisher, year, edition, pages
Royal Society of Chemistry, 2018
National Category
Atom and Molecular Physics and Optics
Identifiers
urn:nbn:se:kth:diva-236372 (URN)10.1039/c8cp04161j (DOI)000449394100037 ()30116802 (PubMedID)2-s2.0-85052796002 (Scopus ID)
Funder
Swedish Research Council, 2017-04278
Note

QC 20181105

Available from: 2018-11-05 Created: 2018-11-05 Last updated: 2018-11-26Bibliographically approved
Cifelli, M., Domenici, V., Chizhik, V. I. & Dvinskikh, S. (2018). N-15-C-13 Dipole Couplings in Smectic Mesophase of a Thermotropic Ionic Liquid. Applied Magnetic Resonance, 49(6), 553-562
Open this publication in new window or tab >>N-15-C-13 Dipole Couplings in Smectic Mesophase of a Thermotropic Ionic Liquid
2018 (English)In: Applied Magnetic Resonance, ISSN 0937-9347, E-ISSN 1613-7507, Vol. 49, no 6, p. 553-562Article in journal (Refereed) Published
Abstract [en]

Unique combination of ionic conductivity and anisotropic physical properties in ionic liquid crystals leads to new dynamic properties exploited in modern technological applications. Structural and dynamics information at atomic level for molecules and ions in mesophases can be obtained by nuclear magnetic resonance (NMR) spectroscopy through the measurements of dipole-dipole spin couplings. While C-13-H-1 and N-15-H-1 dipolar NMR spectra can be routinely acquired in samples with natural isotopic abundance, recording N-15-C-13 dipolar NMR spectra is challenging because of the unfavourable combination of two rare isotopes. In the present study, an approach to measure N-15-C-13 dipole-dipole NMR spectra in static liquid crystalline samples with natural abundance is introduced. We demonstrate that well-resolved spectra can be recorded within 10 h of experimental time using a conventional NMR probe and a moderately strong magnetic field. The technique is applied to a thermotropic smectic mesophase formed by an ionic liquid with imidazolium-based organic cation.

Place, publisher, year, edition, pages
SPRINGER WIEN, 2018
National Category
Condensed Matter Physics
Identifiers
urn:nbn:se:kth:diva-231204 (URN)10.1007/s00723-018-1000-7 (DOI)000434352300003 ()29904238 (PubMedID)2-s2.0-85045624732 (Scopus ID)
Note

QC 20180629

Available from: 2018-06-29 Created: 2018-06-29 Last updated: 2018-06-29Bibliographically approved
Podkorytov, I., Belousov, M., Bondarev, S., Kampf, K., Zhouravleva, G., Dvinskikh, S. & Skrynnikov, N. (2017). Detection of flexible portion of protein chain in Sup35NM amyloid fibrils by means of diffusion-filtered NMR experiment. Paper presented at 42nd Congress of the Federation-of-European-Biochemical-Societies (FEBS) on From Molecules to Cells and Back, SEP 10-14, 2017, Jerusalem, ISRAEL. The FEBS Journal, 284, 215-215
Open this publication in new window or tab >>Detection of flexible portion of protein chain in Sup35NM amyloid fibrils by means of diffusion-filtered NMR experiment
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2017 (English)In: The FEBS Journal, ISSN 1742-464X, E-ISSN 1742-4658, Vol. 284, p. 215-215Article in journal (Refereed) Published
Place, publisher, year, edition, pages
Wiley-Blackwell, 2017
National Category
Chemical Sciences
Identifiers
urn:nbn:se:kth:diva-216636 (URN)000409918903033 ()
Conference
42nd Congress of the Federation-of-European-Biochemical-Societies (FEBS) on From Molecules to Cells and Back, SEP 10-14, 2017, Jerusalem, ISRAEL
Note

QC 20171101

Available from: 2017-11-01 Created: 2017-11-01 Last updated: 2018-05-24Bibliographically approved
Matveev, V. V., Markelov, D. A., Dvinskikh, S., Shishkin, A. N., Tyutyukin, K. V., Penkova, A. V., . . . Milenin, S. A. (2017). Investigation of Melts of Polybutylcarbosilane Dendrimers by 1H NMR Spectroscopy. Scientific Reports, 7(1), Article ID 13710.
Open this publication in new window or tab >>Investigation of Melts of Polybutylcarbosilane Dendrimers by 1H NMR Spectroscopy
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2017 (English)In: Scientific Reports, ISSN 2045-2322, E-ISSN 2045-2322, Vol. 7, no 1, article id 13710Article in journal (Refereed) Published
Abstract [en]

Melts of polybutylcarbosilane (PBC) dendrimers from third (G3) up to sixth (G6) generations are investigated by 1H NMR spectroscopy in a wide temperature range up to 493 K. At room temperature, NMR spectra of G3-G5 dendrimers exhibit resolved, solution-like spectra ("liquid" phase). In contrast, the spectrum of the G6 dendrimer is characterized by a single unresolved broad line at whole temperature range, which supports the presence of an anomalous phase state of G6 at temperatures higher than glass transition temperature. For the first time, an unexpected transition of G5 dendrimer from a molecular liquid state to an anomalous state/phase upon temperature increase has been detected using NMR data. Specifically, an additional wide background line appears in the G5 spectrum above 473 K, and this line corresponds to a G5 state characterized by restricted molecular mobility, i.e., a state similar to the "anomalous" phase of G6 melt. The fraction of the G5 dendrimers in "anomalous" phase at 493 K is approximately 40%. Analysis of the spectral shapes suggests that changes in the G5 dendrimers are reversible with temperature.

Place, publisher, year, edition, pages
Nature Publishing Group, 2017
National Category
Physical Chemistry
Identifiers
urn:nbn:se:kth:diva-227119 (URN)10.1038/s41598-017-13743-z (DOI)000413357500076 ()29057955 (PubMedID)2-s2.0-85032024396 (Scopus ID)
Note

QC 20180508

Available from: 2018-05-08 Created: 2018-05-08 Last updated: 2019-02-07Bibliographically approved
Cifelli, M., Domenici, V., Gorecka, E., Wojcik, M. & Dvinskikh, S. (2017). NMR investigation of a thermotropic liquid crystal showing isotropic-isotropic'-(columnar)-cubic phase transitions. Molecular Crystals and Liquid Crystals, 649(1), 20-30
Open this publication in new window or tab >>NMR investigation of a thermotropic liquid crystal showing isotropic-isotropic'-(columnar)-cubic phase transitions
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2017 (English)In: Molecular Crystals and Liquid Crystals, ISSN 1542-1406, E-ISSN 1563-5287, Vol. 649, no 1, p. 20-30Article in journal (Refereed) Published
Abstract [en]

In this work, we report a first detailed study of the mesophasic behaviour of the calamitic liquid crystal, a (4,4′-bis(4″-carboxybelzyloxy)biphenyl derivate, labelled 9/2 RS/RS, showing an isotropic-isotropic-(columnar)-cubic phase behaviour on cooling. 1H NMR diffusometry allowed to distinguish between the two isotropic phases in terms of diffusion characterized by different Arrhenius activation energy, while 13C NMR static measurements and 2H NMR investigations were of help in understanding the orientational ordering properties of the metastable columnar phase and confirmed the isotropic state of the sample in the cubic phase.

Place, publisher, year, edition, pages
Taylor and Francis Inc., 2017
Keywords
Liquid crystals, Metastable phases, Thermotropic liquid crystals, Arrhenius activation energy, Calamitic liquid crystal, Columnar phase, Isotropic phasis, Isotropic state, NMR diffusometry, Orientational orderings, Static measurements, Activation energy
National Category
Chemical Sciences
Identifiers
urn:nbn:se:kth:diva-216495 (URN)10.1080/15421406.2017.1303595 (DOI)000409263800004 ()2-s2.0-85028753264 (Scopus ID)
Note

QC 20171201

Available from: 2017-12-01 Created: 2017-12-01 Last updated: 2017-12-01Bibliographically approved
Cifelli, M., Domenici, V., Dvinskikh, S., Luckhurst, G. R. & Timimi, B. A. (2017). The twist-bend nematic phase: translational self-diffusion and biaxiality studied by H-1 nuclear magnetic resonance diffusometry. Liquid crystals (Print), 44(1), 204-218
Open this publication in new window or tab >>The twist-bend nematic phase: translational self-diffusion and biaxiality studied by H-1 nuclear magnetic resonance diffusometry
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2017 (English)In: Liquid crystals (Print), ISSN 0267-8292, E-ISSN 1366-5855, Vol. 44, no 1, p. 204-218Article in journal (Refereed) Published
Abstract [en]

Recently, there has been a surge of interest in mesogens exhibiting the twist-bend nematic (N-TB) phase that is shown to be chiral even though formed by effectively achiral molecules. Although it now seems to be clear that the N-TB phase in the bulk is formed by degenerate domains having opposite handedness, the presence of a supramolecular heliconical structure proposed in the Dozov model has been contradicted by the Hoffmann et al. model in which the heliconical arrangement is replaced by a polar nematic phase. The evidence in support of this is that the quadrupolar splitting tensor measured in various experiments is uniaxial and not biaxial as expected for the twist-bend nematic structure. In this debate, among other evidence, the molecular translational diffusion, and its magnitude with respect to that in the nematic phase above the N-TB phase, has also been invoked to eliminate or to confirm one model or the other. We attempt to resolve this issue by reporting the first measurements of the translational self-diffusion coefficients in the nematic and twist-bend nematic phases formed 1 '',7 ''-bis-4-(4'-cyanobiphenyl-4'-yl) heptane (CB7CB). Such measurements certainly appear to resolve the differences between the two models in favour of that for the classic twist-bend nematic phase. [GRAPHICS] .

Place, publisher, year, edition, pages
TAYLOR & FRANCIS LTD, 2017
Keywords
Twist-bend nematic, local phase biaxiality, molecular translational diffusion coefficients, macroscopic rotational diffusion, motional averaging, residual quadrupolar tensors
National Category
Chemical Sciences
Identifiers
urn:nbn:se:kth:diva-205171 (URN)10.1080/02678292.2016.1254292 (DOI)000397105800017 ()
Note

QC 20170411

Available from: 2017-04-11 Created: 2017-04-11 Last updated: 2017-11-29Bibliographically approved
Kharkov, B. B., Chizhik, V. I. & Dvinskikh, S. V. (2016). Broadband cross-polarization-based hetero-nuclear dipolar recoupling for structural and dynamic NMR studies of rigid and soft solids. Journal of Chemical Physics, 144, 034201
Open this publication in new window or tab >>Broadband cross-polarization-based hetero-nuclear dipolar recoupling for structural and dynamic NMR studies of rigid and soft solids
2016 (English)In: Journal of Chemical Physics, ISSN 0021-9606, E-ISSN 1089-7690, Vol. 144, p. 034201-Article in journal (Refereed) Published
Abstract [en]

Dipolar recoupling is an essential part of current solid-state NMR methodology for probing atomic-resolution structure and dynamics in solids and soft matter. Recently described magic-echo amplitude- and phase-modulated cross-polarization heteronuclear recoupling strategy aims at efficient and robust recoupling in the entire range of coupling constants both in rigid and highly dynamic molecules. In the present study, the properties of this recoupling technique are investigated by theoretical analysis, spin-dynamics simulation, and experimentally. The resonance conditions and the efficiency of suppressing the rf field errors are examined and compared to those for other recoupling sequences based on similar principles. The experimental data obtained in a variety of rigid and soft solids illustrate the scope of the method and corroborate the results of analytical and numerical calculations. The technique benefits from the dipolar resolution over a wider range of coupling constants compared to that in other state-of-the-art methods and thus is advantageous in studies of complex solids with a broad range of dynamic processes and molecular mobility degrees.

Place, publisher, year, edition, pages
American Institute of Physics (AIP), 2016
National Category
Natural Sciences
Identifiers
urn:nbn:se:kth:diva-182471 (URN)10.1063/1.4939798 (DOI)000368619100015 ()2-s2.0-84955467088 (Scopus ID)
Note

QG 20160223

Available from: 2016-02-19 Created: 2016-02-19 Last updated: 2017-11-30Bibliographically approved
Organisations
Identifiers
ORCID iD: ORCID iD iconorcid.org/0000-0002-6524-1441

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