Interactions of C2H6 and C2H4 with the homologous series [CnMIM][BF4] ionic liquids at high pressure studied by in situ ATR-FTIR spectroscopy

Kovalev, E. P.; Shalygin, A. S.; Шубин, А. Б.; Kozhevnikov, Ivan V.; Prikhod’ko, Sergey A.; Adonin, Nicolay Yu.; Kazarian, Sergei G.; Martyanov, Oleg N.

doi:10.1016/j.molliq.2021.118082

Cited by 12 publications

(7 citation statements)

References 58 publications

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“…The most intense band at 1300 cm –1 is characteristic of dissolved methane 45 and corresponds to bending vibrations of the CH 4 molecule. According to Kovalev et al, 57 the bands at 1468 and 822 cm –1 indicate dissolved ethane, while the band at 952 cm –1 indicates dissolved ethylene. The 660 cm –1 band refers to dissolved CO 2 .…”

Section: Resultsmentioning

confidence: 96%

Features of Wax Appearance Temperature Determination of Waxy Crude Oil Using Attenuated Total Reflection Fourier Transform Infrared Spectroscopy Under Ambient and High Pressure

Shalygin,

Kozhevnikov,

Morozov

et al. 2023

Appl Spectrosc

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The wax appearance temperature (WAT), being one of the key characteristics of waxy crude oil and other waxy substances, is used for the necessary assessment of the phase stability of materials during various technological processes. However, the determination of this parameter as well as peculiarities of wax formation under high gas pressure suffers from the lack of suitable techniques for this task. To address this issue, an attenuated total reflection Fourier transform infrared spectroscopy (ATR FT-IR) method has been applied for the first time to measure the WAT of waxy crude oil under high gas pressure. Carbon dioxide (CO2), nitrogen, and natural gas were used in the study due to their widespread applicability as injection gases in enhanced oil recovery methods. The S2/S1 versus temperature method based on changes in the band of rocking vibrations of the CH2 group was applied to determine WAT. It was found that the ATR FT-IR method based on the proposed dependence S2/S1 versus temperature gives lower WAT values compared to those observed by viscometry, magnetic resonance imaging inspection, and cross-polarized microscopy methods for the waxy crude oil studied. A detailed analysis was carried out using variable-temperature ATR FT-IR spectra of waxy crude oil in the temperature region near the WAT. Essentially different dynamics of wax crystal formation in waxy oil sample and model paraffin solution were demonstrated during the cooling process. The results obtained by high-pressure ATR FT-IR showed that CO2 and natural gas reduce the WAT, while nitrogen has virtually no effect. In addition, for the studied oil, it was found that high pressure of CO2 and natural gases leads to a visual decrease in the amount of wax crystals precipitated, but not to the complete disappearance of microcrystals at a certain temperature and pressure. The results obtained proved that ATR FT-IR can be an effective method for proper determinations of WAT under high-pressure conditions similar to those met in practice.

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Section: Resultsmentioning

confidence: 96%

Features of Wax Appearance Temperature Determination of Waxy Crude Oil Using Attenuated Total Reflection Fourier Transform Infrared Spectroscopy Under Ambient and High Pressure

Shalygin,

Kozhevnikov,

Morozov

et al. 2023

Appl Spectrosc

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“…For example, the BF 4 – anion showed a blueshift in [Emim][BF 4 ]/AgBF 4 , while it showed a redshift in [Emim][BF 4 ]/AgBF 4 /EG. The possible reason is the hydrogen bond between C 2 H 4 and BF 4 – anion by the effect of EG . Thus, EG can promote C 2 H 4 absorption in Ag-ILs.…”

Section: Resultsmentioning

confidence: 99%

“…Figure 9 shows that the typical vibration peaks of imidazolium IL appeared synchronously in the IL composite absorbent, such as the vibration of C−H (3165 cm −1 ), C�N (1574 cm −1 ), and C�C (1469 cm − anion by the effect of EG. 22 Thus, EG can promote C 2 H 4 absorption in Ag-ILs.…”

Section: Effect Of Different Silver Ion Concentrationsmentioning

confidence: 99%

“…In recent years, absorption technology for C 2 H 4 and C 2 H 6 separation has been applied in industries broadly. Ionic liquids (ILs) have aroused wide attention in many scientific domains because of their good physicochemical properties, such as remarkable desirability structure, ignorable vapor pressure, and simple synthetic procedures. − IL absorbents can complete the separation of olefins/paraffin at normal temperature. − In this regard, it has been discovered that functionalized ILs of functional groups like nitrile (−C  N) or propyne (−C  C−) are effective materials for the separation of gaseous olefins and paraffins . Xing et al found that the separation selectivity of C 2 H 4 /C 2 H 6 increased with the increase of the nitrile functional group of the cation, but the affinity of C 2 H 4 decreased.…”

Section: Introductionmentioning

confidence: 99%

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Synergistic Effect of Silver-Based Ionic Liquid for Ethylene/Ethane Separation

Ren

Liu

Zheng

et al. 2023

Ind. Eng. Chem. Res.

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Separation of ethylene (C 2 H 4 ) and ethane (C 2 H 6 ) is one of the most significant processes in the petrochemical industry. In terms of industrial application, silver nitrate aqueous solution is the most widely used absorbent, but the activity of Ag + and the absorption of C 2 H 4 are not optimistic. Thus, it is urgent to explore new technologies for efficient separation of C 2 H 4 and C 2 H 6 . In this work, several silver-based ionic liquid (Ag-IL) solutions are prepared with ionic liquids (ILs), silver salts, and ethylene glycol (EG). Pure and mixed gas absorption experiments were conducted to explore the effects of various anions and cations of ILs, the molar ratio of IL to silver salt, the EG proportion on absorption performance, and recycling of absorbents. Due to the synergy between ILs, EG, and Ag + , the absorption of C 2 H 4 in [Emim][BF 4 ]/AgBF 4 /EG (2:1:0.1) is up to 101.75 mg/g (2.17 mol C 2 H 4 /mol Ag + ), which is the highest value of IL absorbents reported so far, and the highest selectivity is 37.8. Furthermore, the cyclic stability kept constant after five cycles of absorption−desorption. The interaction mechanism of Ag-ILs was studied by NMR and FTIR spectroscopies. ILs and EG synergistically weaken the electrostatic effect between the anion and cation of AgBF 4 and increase the amount of active silver to enhance the absorption of C 2 H 4 . These task-specific Ag-ILs are expected to be a new medium with commercial potential for C 2 H 4 / C 2 H 6 separation.

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“…Furthermore, this system can be expanded by equipping the instrument with an attenuated total reection (ATR) module to observe real-time changes in concentration. [13][14][15] With these advantages, the ATR-FTIR spectroscopy method offers a new integrated and efficient solution for analyzing ion concentrations in pre-puried samples or complex matrices 11,[16][17][18][19][20][21][22][23][24][25] (Fig. 1).…”

Section: Introductionmentioning

confidence: 99%

Real-time analysis and prediction method of ion concentration using the effect of O–H stretching bands in aqueous solutions based on ATR-FTIR spectroscopy

Baek,

Yun,

Lee

et al. 2024

RSC Adv.

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Interactions of C2H6 and C2H4 with the homologous series [CnMIM][BF4] ionic liquids at high pressure studied by in situ ATR-FTIR spectroscopy

Cited by 12 publications

References 58 publications

Features of Wax Appearance Temperature Determination of Waxy Crude Oil Using Attenuated Total Reflection Fourier Transform Infrared Spectroscopy Under Ambient and High Pressure

Features of Wax Appearance Temperature Determination of Waxy Crude Oil Using Attenuated Total Reflection Fourier Transform Infrared Spectroscopy Under Ambient and High Pressure

Synergistic Effect of Silver-Based Ionic Liquid for Ethylene/Ethane Separation

Real-time analysis and prediction method of ion concentration using the effect of O–H stretching bands in aqueous solutions based on ATR-FTIR spectroscopy

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