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Filippov, A., Bhattacharyya, S. & Shah, F. U. (2019). CO2 absorption and ion mobility in aqueous choline-based ionic liquids. Journal of Molecular Liquids, 276, 748-752
Open this publication in new window or tab >>CO2 absorption and ion mobility in aqueous choline-based ionic liquids
2019 (English)In: Journal of Molecular Liquids, ISSN 0167-7322, E-ISSN 1873-3166, Vol. 276, p. 748-752Article in journal (Refereed) Published
Abstract [en]

CO2 absorption and ion mobility are investigated in a series of 50/50 wt% aqueous solutions of choline-based ionic liquids with different cations and anions: [N1,1,4,2OH][Threo], [N1,1,5,2OH][Threo], [N1,1,6,2OH][Threo], [N1,1,5,2OH][β-ala] and [N1,1,5,2OH][Tau]. The process of CO2 absorption was completed in an hour reaching maximum of absorption capacity 0.07–0.10 wt% to ionic liquid (by 0.4–0.6 molar ratios). A rapid CO2 absorption is observed by the formation of solid product as a result of reaction between CO2 molecule and the ionic liquid. Diffusion coefficients of the cation and anion in the mixture are comparable while the diffusivity of water molecules is found to be quite different from the ions. In the process of CO2 absorption, an increase in the diffusivity of ions is observed due to the precipitation of solid products and depletion of ions contents in the liquid phase of the system. 13C NMR measurements of diffusivity of CO2 enriched with 13C isotope showed that a part of the absorbed CO2 remained in the liquid phase being physically and chemically bound to ions. The ionic liquid is re-cycled by evaporating water and releasing CO2 molecules using vacuum and temperature.

Place, publisher, year, edition, pages
Elsevier, 2019
Keywords
Ionic liquids, CO2 absorption, Nuclear magnetic resonance, Diffusivity of ions, Phase transformations
National Category
Physical Chemistry
Research subject
Chemistry of Interfaces
Identifiers
urn:nbn:se:ltu:diva-72056 (URN)10.1016/j.molliq.2018.12.045 (DOI)000459528600083 ()2-s2.0-85058405735 (Scopus ID)
Note

Validerad;2019;Nivå 2;2019-01-03 (svasva)

Available from: 2018-12-16 Created: 2018-12-16 Last updated: 2019-04-12Bibliographically approved
Filippov, A., Antzutkin, O. & Shah, F. U. (2019). Rapid carbene formation increasing ion diffusivity in an imidazolium acetate ionic liquid confined between polar glass plates. Physical Chemistry, Chemical Physics - PCCP
Open this publication in new window or tab >>Rapid carbene formation increasing ion diffusivity in an imidazolium acetate ionic liquid confined between polar glass plates
2019 (English)In: Physical Chemistry, Chemical Physics - PCCP, ISSN 1463-9076, E-ISSN 1463-9084Article in journal (Refereed) Epub ahead of print
Abstract [en]

1-Ethyl-3-methyl-imidazolium acetate ([EMIM][OAc]) is one of the most widely used ionic liquids for various applications. This study is focussed on the chemical stability of [EMIM][OAc] on the surfaces of polar glass plates. 1H and 13C NMR spectroscopy and NMR diffusometry of [EMIM][OAc] IL confined between glass plates with a specific surface area 105–106 m−1 are thoroughly investigated. A rapid and spontaneous reaction took place on the surfaces of glass plates leading to the formation of neutral chemical moieties as evident by the appearance of new signals in the 1H NMR spectra. These new products are assigned as N-heterocyclic carbene (NHC) and acetic acid. These neutral chemical moieties have significantly increased the ion diffusivity by dissociation of the cation and the anion in [EMIM][OAc] IL. The yield and rate of formation of NHC and acetic acid are found to increase with the increasing surface area of polar glass plates and the time of contact between the IL and glass surfaces. Based on NMR spectroscopy, a dissociative reaction mechanism is proposed for the formation of free NHC in the neat [EMIM][OAc] IL.

Place, publisher, year, edition, pages
Royal Society of Chemistry, 2019
National Category
Natural Sciences Chemical Sciences Physical Chemistry
Research subject
Chemistry of Interfaces
Identifiers
urn:nbn:se:ltu:diva-76117 (URN)10.1039/C9CP04504J (DOI)
Available from: 2019-09-25 Created: 2019-09-25 Last updated: 2019-10-07
Filippov, A., Antzutkin, O. & Shah, F. U. (2019). Reactivity of CO2 with aqueous choline-based ionic liquids probed by solid-state NMR spectroscopy. Journal of Molecular Liquids, 286, Article ID 110918.
Open this publication in new window or tab >>Reactivity of CO2 with aqueous choline-based ionic liquids probed by solid-state NMR spectroscopy
2019 (English)In: Journal of Molecular Liquids, ISSN 0167-7322, E-ISSN 1873-3166, Vol. 286, article id 110918Article in journal (Refereed) Published
Abstract [en]

CO2 absorption in a series of choline-based ionic liquids is investigated using solid-state 13C and 15N MAS NMR spectroscopy. Natural abundance and 13C enriched CO2 gas was purged through 50 wt% aqueous solutions of alkyldimethyl(2-hydroxyethyl)ammonium threonine, [N1,1,n,2OH][Threo], (alkyl = butyl, pentyl and hexyl) and pentyldimethyl(2-hydroxyethyl)ammonium taurine [N1,1,5,2OH][Tau]. The process of CO2 absorption results in precipitation of a solid sediment, which stays in equilibrium with the liquid phase. Upon degassing of the sample, the sediment is dissolved back into the IL-aqueous phase. Solid state 13C and 15N MAS NMR data suggest that the solid sediment is composed of neutral threonine (or taurine) in the zwitterionic forms and the liquid phase contained the products of reactions between the ionic liquids and CO2 molecules. A plausible mechanism for formation of the solid sediments and the reaction products in liquid phases is suggested.

Place, publisher, year, edition, pages
Elsevier, 2019
Keywords
CO2 absorption, Aqueous choline-based ionic liquids, Liquid-solid equilibrium, 13C and 15N MAS, CP-MAS NMR
National Category
Physical Chemistry
Research subject
Chemistry of Interfaces
Identifiers
urn:nbn:se:ltu:diva-73873 (URN)10.1016/j.molliq.2019.110918 (DOI)000474308400033 ()2-s2.0-85065237523 (Scopus ID)
Note

Validerad;2019;Nivå 2;2019-05-14 (johcin)

Available from: 2019-05-07 Created: 2019-05-07 Last updated: 2019-08-16Bibliographically approved
Hafeez, A., Akhter, Z., Gallagher, J. F., Khan, N. A., Gul, A. & Shah, F. U. (2019). Synthesis, Crystal Structures, and Spectroscopic Characterization of Bis-aldehyde Monomers and Their Electrically Conductive Pristine Polyazomethines. Polymers, 11(9), Article ID 1498.
Open this publication in new window or tab >>Synthesis, Crystal Structures, and Spectroscopic Characterization of Bis-aldehyde Monomers and Their Electrically Conductive Pristine Polyazomethines
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2019 (English)In: Polymers, ISSN 2073-4360, E-ISSN 2073-4360, Vol. 11, no 9, article id 1498Article in journal (Refereed) Published
Abstract [en]

Bis-aldehyde monomers 4-(4′-formyl-phenoxy)benzaldehyde (3a), 3-methoxy-4-(4′-formyl-phenoxy)benzaldehyde (3b), and 3-ethoxy-4-(4′-formyl-phenoxy)benzaldehyde (3c) were synthesized by etherification of 4-fluorobenzaldehyde (1) with 4-hydroxybenzaldehyde (2a), 3-methoxy-4-hydroxybenzaldehyde (2b), and 3-ethoxy-4-hydroxybenzaldehyde (2c), respectively. Each monomer was polymerized with p-phenylenediamine and 4,4′-diaminodiphenyl ether to yield six poly(azomethine)s. Single crystal X-ray diffraction structures of 3b and 3c were determined. The structural characterization of the monomers and poly(azomethine)s was performed by FT-IR and NMR spectroscopic techniques and elemental analysis. Physicochemical properties of polymers were investigated by powder X-ray diffraction, thermogravimetric analysis (TGA), viscometry, UV–vis, spectroscopy and photoluminescence. These polymers were subjected to electrical conductivity measurements by the four-probe method, and their conductivities were found to be in the range 4.0 × 10−5 to 6.4 × 10−5 Scm−1, which was significantly higher than the values reported so far.

Place, publisher, year, edition, pages
MDPI, 2019
Keywords
Polyazomethines, single crystals, bis-aldehydes, spectroscopic characterization, conductivity, poly(Schiff base)s
National Category
Polymer Chemistry Physical Chemistry
Research subject
Chemistry of Interfaces
Identifiers
urn:nbn:se:ltu:diva-75995 (URN)10.3390/polym11091498 (DOI)31540265 (PubMedID)2-s2.0-85072514470 (Scopus ID)
Note

Validerad;2019;Nivå 2;2019-09-18 (johcin)

Available from: 2019-09-13 Created: 2019-09-13 Last updated: 2019-10-02Bibliographically approved
Mushtaq, I., Akhter, Z. & Shah, F. U. (2019). Tunable Self-Assembled Nanostructures of Electroactive PEGylated Tetra(Aniline) Based ABA Triblock Structures in Aqueous Medium. Frontiers in Chemistry, 7, 1-10, Article ID 518.
Open this publication in new window or tab >>Tunable Self-Assembled Nanostructures of Electroactive PEGylated Tetra(Aniline) Based ABA Triblock Structures in Aqueous Medium
2019 (English)In: Frontiers in Chemistry, E-ISSN 2296-2646, Vol. 7, p. 1-10, article id 518Article in journal (Refereed) Published
Abstract [en]

PEGylated tetra(aniline) ABA triblock structure PEG-TANI-PEG (2) consisting of tetra(aniline) (TANI) and polyethylene glycol (PEG) was synthesized by coupling the tosylated-PEG to boc-protected NH2/NH2 TANI (1) through a simple nucleophilic substitution reaction. Deprotection of 2 resulted in a leucoemeraldine base state of TANI (2-LEB), which was oxidized to stable emeraldine base (2-EB) state. 2-EB was doped with 1 M HCl to emeraldine salt (2-ES) state. FTIR, 1H and 13C NMR and UV-Vis-NIR spectroscopy, and MS (ESI) was used for structural characterization. The synthesized triblock structure exhibited good electroactivity as confirmed by CV and UV-Vis-NIR spectroscopy. Self-assembling of the triblock structure in aqueous medium was assessed by DLS, TEM, and SEM. Spherical aggregates were observed with variable sizes depicting the effect of concentration and oxidation of 2-LEB. Further, the aggregates showed acid/base sensitivity as evaluated by doping and dedoping of 2-EB with 1 M HCl and 1 M NH4OH, respectively. Future applications in drug delivery and sensors are envisaged for such tunable self-assembled nanostructures in aqueous media.

Place, publisher, year, edition, pages
Frontiers Media S.A., 2019
Keywords
triblock nanostructures, PEGylation, redox activity, aqueous self-assembly, tunable self-assembled structures
National Category
Polymer Chemistry Physical Chemistry
Research subject
Chemistry of Interfaces
Identifiers
urn:nbn:se:ltu:diva-75367 (URN)10.3389/fchem.2019.00518 (DOI)000477062400001 ()31403042 (PubMedID)2-s2.0-85072212160 (Scopus ID)
Note

Validerad;2019;Nivå 2;2019-08-06 (johcin)

Available from: 2019-07-29 Created: 2019-07-29 Last updated: 2019-09-23Bibliographically approved
Filippov, A., Azancheev, N., Gibaydullin, A., Bhattacharyya, S., Antzutkin, O. N. & Shah, F. U. (2018). Dynamic Properties of Imidazolium Orthoborate Ionic Liquids Mixed with Polyethylene Glycol Studied by NMR Diffusometry and Impedance Spectroscopy. Magnetic Resonance in Chemistry, 56(2), 113-119
Open this publication in new window or tab >>Dynamic Properties of Imidazolium Orthoborate Ionic Liquids Mixed with Polyethylene Glycol Studied by NMR Diffusometry and Impedance Spectroscopy
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2018 (English)In: Magnetic Resonance in Chemistry, ISSN 0749-1581, E-ISSN 1097-458X, Vol. 56, no 2, p. 113-119Article in journal (Refereed) Published
Abstract [en]

We used 1H pulsed field gradient (PFG) NMR to study the self-diffusion of polyethylene glycol (PEG) with average molecular mass of 200 and ions in mixtures of PEG with imidazolium bis(mandelato)borate (BMB) and imidazolium bis(oxalato)borate (BOB) ionic liquids (ILs). The ionic liquid was mixed with PEG in the concentration range of 0–100 wt%. Within the temperature range of 295 to 353 K, the diffusion coefficient of BMB is slower than that of the imidazolium cation. The diffusion coefficients of PEG, as well as the imidazolium cation and BMB anions, differ under all experimental conditions tested. This demonstrates that the IL in the mixture is present in at least a partially dissociated state. Generally, increasing the concentration of PEG leads to an increase in the diffusion coefficients of PEG and both the ions, and decreases their activation energy for diffusion. NMR chemical shift alteration analysis showed that the presence of PEG changes the chemical shifts of both ions but in different directions. Impedance spectroscopy was used to measure the ionic conductivity of the ionic liquids mixed with PEG.

Place, publisher, year, edition, pages
John Wiley & Sons, 2018
National Category
Chemical Sciences Physical Chemistry
Research subject
Chemistry of Interfaces
Identifiers
urn:nbn:se:ltu:diva-64929 (URN)10.1002/mrc.4636 (DOI)000419519200009 ()28752526 (PubMedID)2-s2.0-85040248332 (Scopus ID)
Note

Validerad;2018;Nivå 2;2018-01-09 (svasva)

Available from: 2017-07-31 Created: 2017-07-31 Last updated: 2018-12-14Bibliographically approved
Khan, A. S., Man, Z., Bustam, M. A., Nasrullah, A., Ullah, Z., Sarwono, A., . . . Muhammad, N. (2018). Efficient Conversion of Lignocellulosic Biomass to Levulinic Acid Using Acidic Ionic Liquids. Carbohydrate Polymers, 181, 208-214
Open this publication in new window or tab >>Efficient Conversion of Lignocellulosic Biomass to Levulinic Acid Using Acidic Ionic Liquids
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2018 (English)In: Carbohydrate Polymers, ISSN 0144-8617, E-ISSN 1879-1344, Vol. 181, p. 208-214Article in journal (Refereed) Published
Abstract [en]

In the present research work, dicationic ionic liquids, containing 1,1-Bis(3-methylimidazolium-1-yl) butylene ([C4(Mim)2]) cation with counter anions [(2HSO4)(H2SO4)0], [(2HSO4)(H2SO4)2] and [(2HSO4)(H2SO4)4] were synthesised. ILs structures were confirmed using 1H NMR spectroscopy. Thermal stability, Hammett acidity, density and viscosity of ILs were determined. Various types of lignocellulosic biomass such as rubber wood, palm oil frond, bamboo and rice husk were converted into LA. Among the synthesized ionic liquids, [C4(Mim)2][(2HSO4)(H2SO4)4] showed higher % yield of LA up to 47.52 from bamboo biomass at 100 °C for 60 min, which is the better yield at low temperature and short time compared to previous reports. Surface morphology, surface functional groups and thermal stability of bamboo before and after conversion into LA were studied using SEM, FTIR and TGA analysis, respectively. This one-pot production of levulinic acid from agro-waste will open new opportunity for the conversion of sustainable biomass resources into valuable chemicals.

Place, publisher, year, edition, pages
Elsevier, 2018
National Category
Physical Chemistry
Research subject
Chemistry of Interfaces
Identifiers
urn:nbn:se:ltu:diva-66250 (URN)10.1016/j.carbpol.2017.10.064 (DOI)000418661000026 ()29253965 (PubMedID)2-s2.0-85032002177 (Scopus ID)
Note

Validerad;2017;Nivå 2;2017-11-01 (andbra)

Available from: 2017-10-25 Created: 2017-10-25 Last updated: 2018-01-15Bibliographically approved
An, R., Zhou, G., Zhu, Y., Zhu, W., Huang, L. & Shah, F. U. (2018). Friction of Ionic Liquid–Glycol Ether Mixtures at Titanium Interfaces: Negative Load Dependence. Advanced Materials Interfaces, 5(14), Article ID 1800266.
Open this publication in new window or tab >>Friction of Ionic Liquid–Glycol Ether Mixtures at Titanium Interfaces: Negative Load Dependence
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2018 (English)In: Advanced Materials Interfaces, ISSN 2196-7350, Vol. 5, no 14, article id 1800266Article in journal (Refereed) Published
Abstract [en]

Structural reorientation of alkyl chains in the phosphonium cation of orthoborate ionic liquid mixed with glycol ether occurs with increasing normal load of the AFM tip. The flat reoriented structure, similar to the ‘blooming lotus leaf’, produces a new sliding interface that is responsible for the observed lower friction at higher loads. This work is reported by Rong An, Liangliang Huang, Faiz Ullah Shah and co‐workers in article number 1800263.

Place, publisher, year, edition, pages
John Wiley & Sons, 2018
National Category
Chemical Sciences Physical Chemistry
Research subject
Chemistry of Interfaces; Chemistry of Interfaces
Identifiers
urn:nbn:se:ltu:diva-70453 (URN)10.1002/admi.201870066 (DOI)
Available from: 2018-08-16 Created: 2018-08-16 Last updated: 2018-08-16Bibliographically approved
An, R., Zhou, G., Zhu, Y., Zhu, W., Huang, L. & Shah, F. U. (2018). Friction of Ionic Liquid–Glycol Ether Mixtures at Titanium Interfaces: Negative Load Dependence. Advanced Materials Interfaces, 5(14), Article ID 1800263.
Open this publication in new window or tab >>Friction of Ionic Liquid–Glycol Ether Mixtures at Titanium Interfaces: Negative Load Dependence
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2018 (English)In: Advanced Materials Interfaces, ISSN 2196-7350, Vol. 5, no 14, article id 1800263Article in journal (Refereed) Published
Abstract [en]

The atomic force microscopy experiments and nonequilibrium molecular dynamics (NEMD) simulations demonstrate a negative friction–load dependence to ionic liquid–glycol ether mixtures, that is, the friction decreases as the normal load increases. NEMD simulations reveal a structural reorientation of the studied ionic liquid (IL): as the normal load increases, the cation alkyl chains of ILs change the orientation to preferentially parallel to the tip scanning path. The flat‐oriented IL structures, similar to the “blooming lotus leaf,” produce a new sliding interface and reduce the friction. A further molecular dynamics simulation is carried out by adopting slit‐pore models to mimic the tip approaching process to confirm the dynamics of ILs. A faster diffusion of ILs in the smaller slit pore is observed. The faster diffusion of ILs in the more confined slit pore facilitates the structural reorientation of ILs. The resulted new sliding surface is responsible for the observed smaller friction at higher loads, also known as the negative friction–load dependence. These findings provide a fundamental explanation to the role of ILs in interfacial lubrications. They help to understand liquid flow properties under confinement, with implications for the development of better nanofluidic devices.

Place, publisher, year, edition, pages
John Wiley & Sons, 2018
National Category
Chemical Sciences Physical Chemistry
Research subject
Chemistry of Interfaces
Identifiers
urn:nbn:se:ltu:diva-68631 (URN)10.1002/admi.201800263 (DOI)000439739000010 ()2-s2.0-85046361446 (Scopus ID)
Note

Validerad;2018;Nivå 2;2018-07-24 (inah)

Available from: 2018-05-04 Created: 2018-05-04 Last updated: 2018-08-21Bibliographically approved
Shah, F. U., Holmgren, A., Rutland, M. W., Glavatskih, S. & Antzutkin, O. (2018). Interfacial Behavior of Orthoborate Ionic Liquids at Inorganic Oxide Surfaces Probed by NMR, IR and Raman Spectroscopy. The Journal of Physical Chemistry C, 122(34), 19687-19698
Open this publication in new window or tab >>Interfacial Behavior of Orthoborate Ionic Liquids at Inorganic Oxide Surfaces Probed by NMR, IR and Raman Spectroscopy
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2018 (English)In: The Journal of Physical Chemistry C, ISSN 1932-7447, E-ISSN 1932-7455, Vol. 122, no 34, p. 19687-19698Article in journal (Refereed) Published
Abstract [en]

Absorption modes and reactivity of non-halogenated ionic liquids (ILs) at inorganic oxide surfaces of γ-Al2O3, MgO and SiO2 particles were characterized using multinuclear (11B, 31P and 29Si) solid-state magic-angle-spinning NMR, FTIR and Raman spectroscopy. ILs are composed of the trihexyl(tetradecyl)phosphonium cation, [P6,6,6,14]+, and bis(mandelato)borate, [BMB]-, or bis(salicylato)borate, [BScB]-, anions. Spectroscopic measurements were performed on room temperature (298 K) samples and samples exposed to 15 hours of heating at 373 K. The single pulse 11B NMR data of heated [P6,6,6,14][BMB] mixed with the inorganic oxides showed a significant change in spectra of the anion for all three oxides. In contrast, no such spectral changes were detected for heated [P6,6,6,14][BScB] mixed with the inorganic oxides. 31P MAS NMR data for the IL/metal oxide systems revealed interactions between [P6,6,6,14]+ and the surfaces of oxides. A significant intensity of 31P CP-MAS NMR signals indicated a low mobility of cations in these systems. The existence of strongly adhered surface layers of ILs on SiO2 particles was also confirmed by 1H-29Si CP-MAS NMR spectroscopy. FTIR and Raman spectroscopic data revealed strong interactions between the anions and the inorganic surfaces and there is strong correlation with the data obtained from NMR spectroscopy. Although their chemical structures are rather similar, the [BScB]- anion is more stable than the [BMB]- anion at the inorganic oxide surface.

Place, publisher, year, edition, pages
American Chemical Society (ACS), 2018
National Category
Physical Chemistry Chemical Process Engineering
Research subject
Chemistry of Interfaces; Chemical Technology
Identifiers
urn:nbn:se:ltu:diva-70194 (URN)10.1021/acs.jpcc.8b06049 (DOI)000443923500041 ()2-s2.0-85052316588 (Scopus ID)
Note

Validerad;2018;Nivå 2;2018-10-05 (johcin)

Available from: 2018-08-01 Created: 2018-08-01 Last updated: 2018-12-14Bibliographically approved
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