Decomposition and oligomerization of 2,3-naphthyridine under high-pressure and high-temperature conditions

Shinozaki, Ayako; Mimura, Koichi; Nishida, Tamihito

doi:10.1038/s41598-019-43868-2

Cited by 8 publications

(10 citation statements)

References 36 publications

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“…In contrast, nitrogen atoms are selectively released from aromatic rings with the oligomerization when two nitrogen atoms were localized in one aromatic ring forming a N−N bonding as in 2,3-Nap. 38 In case of 2,3-Nap, the N−N covalent bond is easily dissociated under high temperature and the aromatic ring was subjected to both nitrogen-and carbon-opening reactions.…”

Section: ■ Discussionmentioning

confidence: 99%

“…The temperature was measured using a K-type thermocouple attached to the top of the cylinder. The details of the apparatus were described in a previous study . The reaction time for all experiments was fixed at 4 h.…”

Section: Experimental Sectionmentioning

confidence: 99%

“…25 The temperature-induced chemical reaction of 2,3-Nap was reported at >523 K at 0.5 and 1.0 GPa and >548 K at 1.5 GPa. 38 The reaction products were investigated by using gas chromatograph-mass spectrometry (GC/MS) and matrixassisted laser desorption/ionization (MALDI) time of flight (TOF) MS, and cleavage of the aromatic ring and release of nitrogen atoms with the formation of o-xylene and o-tolunitrile were indicated. In addition, the decomposed products reacted with the remaining 2,3-Nap to form larger oligomers.…”

Section: ■ Introductionmentioning

confidence: 99%

“…The details of the apparatus were described in a previous study. 38 The reaction time for all experiments was fixed at 4 h. The samples after the HPHT experiments were recovered from the capsules in distilled dichloromethane solvent to prevent the reaction products from escaping. The solution was initially filtered by the carbon-free glass filter to extract soluble products from insoluble products.…”

Section: ■ Introductionmentioning

confidence: 99%

“…The recovered amorphous products contained a considerable amount of nitrogen bonded to both sp 3 and sp 2 carbons . The temperature-induced chemical reaction of 2,3-Nap was reported at >523 K at 0.5 and 1.0 GPa and >548 K at 1.5 GPa . The reaction products were investigated by using gas chromatograph-mass spectrometry (GC/MS) and matrix-assisted laser desorption/ionization (MALDI) time of flight (TOF) MS, and cleavage of the aromatic ring and release of nitrogen atoms with the formation of o -xylene and o -tolunitrile were indicated.…”

Section: Introductionmentioning

confidence: 99%

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Polymerization Mechanism of Nitrogen-Containing Heteroaromatic Compound Under High-Pressure and High-Temperature Conditions

et al. 2020

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Hydrogenated carbon nitride is synthesized by polymerization of 1,5-naphthyridine, a nitrogen-containing heteroaromatic compound, under high-pressure and high-temperature conditions. The polymerization progressed significantly at temperatures above 573 K at 0.5 GPa and above 623 K at 1.5 GPa. The reaction temperature was relatively lower than that observed for pure naphthalene, suggesting that the reaction temperature is considerably lowered when nitrogen atoms exist in the aromatic ring structure. The polymerization reaction largely progresses without significant change in the N/C ratio. Three types of dimerization are identified; naphthylation, exact dimerization, and dimerization with hydrogenation as determined from the gas chromatograph–mass spectrometry analysis of soluble products. Infrared spectra suggest that hydrogenation products were likely to be formed with sp3 carbon and NH bonding. Solid-state 13C nuclear magnetic resonance reveals that the sp3/sp2 ratio is 0.14 in both the insoluble solids synthesized at 0.5 and 1.5 GPa. Not only the dimers but also soluble heavier oligomers and insoluble polymers formed through more extensive polymerization. The major reaction mechanism of 1,5-Nap was common to both the 0.5 and 1.5 GPa experiments, although the required reaction temperature increased with increasing pressure and aromatic rings preferentially remained at the higher pressure.

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Section: ■ Discussionmentioning

confidence: 99%

Section: Experimental Sectionmentioning

confidence: 99%

Section: ■ Introductionmentioning

confidence: 99%

Section: ■ Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Polymerization Mechanism of Nitrogen-Containing Heteroaromatic Compound Under High-Pressure and High-Temperature Conditions

et al. 2020

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Phase Relation and Reactivity of 1-Hexene under High-Pressure and High-Temperature Conditions

Shinozaki,

Kawano,

Nagai

2024

J. Phys. Chem. C

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The phase changes and chemical reactions of 1-hexene under highpressure and high-temperature (HPHT) conditions were investigated by using diamond anvil cells and Raman spectroscopy. The slow crystallization of 1-hexene was observed after compression to approximately 3 GPa at room temperature. Solid 1-hexene was dominant up to 20.7 GPa without any phase changes. Under HPHT conditions, the intensities of the Raman peaks related to sp 2 carbon were selectively reduced, and a new C�C vibration mode appeared, indicating an irreversible reaction. The reaction threshold temperature decreased with an increase in pressure to approximately 100 °C at 3 GPa, where the reaction progressed from liquid 1-hexene. In contrast, the reaction threshold temperature increased with increasing pressure above 3 GPa, at which point the reaction progressed from a solid 1-hexene. Oligomers of 1-hexene up to at least 8mers were detected from gas chromatography−mass spectrometry analysis of the reaction products recovered from 120 and 240 °C at 1.5 GPa by further experiments using a piston− cylinder-type high-pressure and high-temperature apparatus. The major dimers in the reaction products were linear and branched alkenes bearing C 12 H 24 .

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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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Decomposition and oligomerization of 2,3-naphthyridine under high-pressure and high-temperature conditions

Cited by 8 publications

References 36 publications

Polymerization Mechanism of Nitrogen-Containing Heteroaromatic Compound Under High-Pressure and High-Temperature Conditions

Polymerization Mechanism of Nitrogen-Containing Heteroaromatic Compound Under High-Pressure and High-Temperature Conditions

Phase Relation and Reactivity of 1-Hexene under High-Pressure and High-Temperature Conditions

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

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Decomposition and oligomerization of 2,3-naphthyridine under high-pressure and high-temperature conditions

Cited by 8 publications

References 36 publications

Polymerization Mechanism of Nitrogen-Containing Heteroaromatic Compound Under High-Pressure and High-Temperature Conditions

Polymerization Mechanism of Nitrogen-Containing Heteroaromatic Compound Under High-Pressure and High-Temperature Conditions

Phase Relation and Reactivity of 1-Hexene under High-Pressure and High-Temperature Conditions

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