Raman Spectroscopy Study on Chemical Transformations of Propane at High Temperatures and High Pressures

Kudryavtsev, D. A.; Fedotenko, Timofey; Koemets, Egor; Khandarkhaeva, Saiana; Kutcherov, Vladimir; Dubrovinsky, Leonid

doi:10.1038/s41598-020-58520-7

Cited by 8 publications

(8 citation statements)

References 43 publications

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“…Chemical changes in hydrocarbons under high pressure–high temperature conditions have been observed in a number of previous studies on methane and ethane, , as well as propane, including reactions to products with no measurable Raman spectrum. For instance, as shown in ref , benzene was compressed at 300 K, and no measurable Raman spectrum was observed above 43 GPa.…”

Section: Discussionmentioning

confidence: 80%

Phase Diagram of Ethane above 300 K

2022

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We have measured the melting curve of ethane from 300 to 450 K. Our results indicate that to describe all melting curve data above the triple point, it is necessary to account for a kink in the melting curve where the phase III−phase IV solid−solid transition intersects the melting curve. In the solid state, we observe some evidence for a new phase existing close to the melting curve above 300 K. We have observed that the decomposition of ethane at high pressure and temperature can be catalyzed by ruby or samarium-doped yttrium aluminum garnet at a surprisingly low temperature of 375 K.

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Section: Discussionmentioning

confidence: 80%

Phase Diagram of Ethane above 300 K

2022

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“…Raman spectroscopy has been used to report the kinetics of chemical transformations in the process, [43] including in a high temperature. [44] For this purpose, we analyzed the Raman spectral data and a PCA was calculated. The principal component loading graph is given in Figure 4.…”

Section: Liquid Samplesmentioning

confidence: 99%

Chemical Reaction: Understanding the Key to the Formation of Carbonaceous Materials from Sucralose

et al. 2021

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An interesting way to understand carbonaceous materials structure and their properties is to evaluate the chemical reactions involved in their production. However, there are only a few published works describing the main reactions. Here, we report how chemical reactions can help understand the degradation of sucralose in hydrothermal carbonization (HTC), and the formation of hydrochar. To this end, sucralose is treated for 3.0 h, and Raman and mass spectrum data of hydrochar and liquid samples are analyzed, as well quantum chemistry calculations (QCC). The results show that ionization of sucralose is the most important step in the degradation process, and the use of FeCl2 can speed up the degradation process. However, pH leads to ionization, dehydration and dechlorination, but glycosidic bond cleavage is a common subsequent reaction. Raman analysis present hydrochar samples with oxygen‐containing groups and aromatic/heterocyclic ring bands which are important in functionalized materials. Morphologically, the samples generated at initial pH=10.00, and in the presence of MnCl2 presented the smallest microspheres and this phenomenon may be related to the amount of degradation products. Finally, the evaluation of Raman spectroscopy and mass spectrometry data using principal components analysis is useful to suggest the degradation pathways and hydrochar formation processes.

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“…Chemical reactions of propane (C 3 H 8 ) progressed partially at temperatures of approximately 1000 K and pressures of 3−22 GPa to form both heavier alkanes, such as butane (C 4 H 10 ), pentane (C 5 H 12 ), and hexane (C 6 H 14 ), and lighter hydrocarbons such as methane, suggesting that C−C bond formation and cleavage of C−C and C−H bonds occurred simultaneously. 26 The formation of hydrogenated amorphous carbon from n-hexane at ∼20 GPa and 1000 K and also diamond formation from longer n-alkanes (C 8 H 18 to C 19 C 40 ) above 3000 K at 10−20 GPa were reported. 27,28 experimental studies have suggested that when the unbranched alkane chains reach some critical length, the chains assume a folded conformation rather than a linear one.…”

Section: ■ Introductionmentioning

confidence: 99%

“…The formation of ethane and heavier hydrocarbons with the dehydrogenation and polymerization of methane progressed above 1000 K, comparable to the HPHT conditions of Earth’s upper mantle and the interiors of icy planets. − The reaction advanced significantly with increasing temperature and eventually formed graphitic carbon/diamond above 3000 K. Thermodynamic calculations and theoretical studies have pointed out that alkanes heavier than methane become more stable with increasing pressure and temperature, , but much less is known on the chemical reactions of heavier alkanes under HPHT conditions. Chemical reactions of propane (C 3 H 8 ) progressed partially at temperatures of approximately 1000 K and pressures of 3–22 GPa to form both heavier alkanes, such as butane (C 4 H 10 ), pentane (C 5 H 12 ), and hexane (C 6 H 14 ), and lighter hydrocarbons such as methane, suggesting that C–C bond formation and cleavage of C–C and C–H bonds occurred simultaneously . The formation of hydrogenated amorphous carbon from n -hexane at ∼20 GPa and 1000 K and also diamond formation from longer n -alkanes (C 8 H 18 to C 19 C 40 ) above 3000 K at 10–20 GPa were reported. , Theoretical and experimental studies have suggested that when the unbranched alkane chains reach some critical length, the chains assume a folded conformation rather than a linear one. , Pressure-induced transition from linear to fold molecular conformations was observed in longer n -alkanes (C 7 H 16 , C 18 H 38 , and C 23 H 48 ), where the reaction pressure decreased as the carbon numbers of n -alkanes increased. − Kinks in fold structures are likely to facilitate cracking of the longer chains; hence, reactions in longer alkanes exposed to high temperatures after compression may be the result of individual processes on the alkane chain length, and it is necessary to investigate the reaction individually. , …”

Section: Introductionmentioning

confidence: 99%

Effect of Pressure on the Thermal Cracking and Polymerization of Pentacosane (n-C₂₅), an n-Alkane

Shinozaki

2022

ACS Earth Space Chem.

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Hydrocarbons are important carbon components in the subducting slab and play a crucial role in the Earth’s deep carbon cycle. In this study, the thermal reaction of pentacosane (n-C25), a long n-alkane, was experimentally investigated under high-pressure and high-temperature conditions at 0.5–1.5 GPa and 360–400 °C. The gas chromatography–mass spectrometry (GC/MS) analyses of the reaction products revealed that the radical reaction of n-C25 proceeded above 360 °C at 0.5 GPa and above 380 °C at 1.5 GPa, while the rate constant decreased with increasing pressure. Lighter n-alkanes and heavier straight/branched alkanes were detected in the reaction products. The formation of lighter n-alkanes indicates thermal cracking progression, even at high-pressure conditions. During thermal cracking, lighter 1-alkenes were likely to form but were instead rapidly added to the initial n-C25 to form heavier alkanes when enhanced by pressure. Thus, lighter 1-alkenes were not detected in the reaction products. As the secondary reaction, the heavier alkanes were polymerized with dehydrogenation to form amorphous carbon when the remaining percentage of the initial material became <10% and <20% at 0.5 and 1.5 GPa, respectively, while the lighter n-alkanes were detected simultaneously. Both lighter alkanes with high H/C ratios and amorphous carbon with a low H/C ratio eventually formed through the reaction of n-alkanes at high-pressure and high-temperature conditions of the deep Earth.

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Raman Spectroscopy Study on Chemical Transformations of Propane at High Temperatures and High Pressures

Cited by 8 publications

References 43 publications

Phase Diagram of Ethane above 300 K

Phase Diagram of Ethane above 300 K

Chemical Reaction: Understanding the Key to the Formation of Carbonaceous Materials from Sucralose

Effect of Pressure on the Thermal Cracking and Polymerization of Pentacosane (n-C₂₅), an n-Alkane

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Raman Spectroscopy Study on Chemical Transformations of Propane at High Temperatures and High Pressures

Cited by 8 publications

References 43 publications

Phase Diagram of Ethane above 300 K

Phase Diagram of Ethane above 300 K

Chemical Reaction: Understanding the Key to the Formation of Carbonaceous Materials from Sucralose

Effect of Pressure on the Thermal Cracking and Polymerization of Pentacosane (n-C25), an n-Alkane

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Effect of Pressure on the Thermal Cracking and Polymerization of Pentacosane (n-C₂₅), an n-Alkane