Formation of complex hydrocarbon systems from methane at the upper mantle thermobaric conditions

Abstract

the existence of methane in the earth's mantle does not cause any doubt, however, its possible chemical transformation under the mantle thermobaric conditions is not enough known. investigation of methane at the upper mantle thermobaric conditions, using diamond anvil cells, demonstrated the possible formation of ethane, propane and n-butane from methane, however, theoretical calculations of methane behaviour at extreme temperature and pressure predicted also heavier hydrocarbons. We experimentally investigated the chemical transformations of methane at the upper mantle thermobaric conditions, corresponding to the depth of 70-80 km (850-1000 K, 2.5 GPa), using "Toroid"-type Large reactive volume device and gas chromatography. the experimental results demonstrated the formation of the complex hydrocarbon mixture up to c 7 with linear, branched and cycled structures and benzene. Unsaturated hydrocarbons were detected on the trace level in the products mixture. the increasing of exposure time leaded to growth of heavier components in the product systems. the data obtained suggest possible existence of complex hydrocarbon mixtures at the upper mantle thermobaric conditions and provide a new insight on the possible pathways of the hydrocarbons synthesis from methane in the upper mantle.

Advances in carbon isotope analysis of trapped methane and volatile hydrocarbons in crystalline rock cores

“…The origin and fate of methane (CH 4 ) continues to be a compelling topic of investigation, both on Earth, for its important role in energy and climate studies, in biogeochemical cycling on the planet's surface and subsurface biosphere, and for moons and planets elsewhere in the solar system. [1][2][3][4][5][6][7][8] Biotic CH 4 is produced either microbially or through the thermal decomposition of organic matter whereas abiotic CH 4 is produced through chemical reactions that do not directly involve organic matter but include both high-temperature processes related to magmatic activity [9][10][11][12] and low-temperature abiotic organic synthesis related to processes of water-rock reaction such as serpentinization. 3,13 Differentiating between such sources remains a challenge.…”

Pressure-Induced Hydrogen Transfer in 2-Butyne via a Double CH···π Aromatic Transition State

“…Hydrogen is the most abundant element in the universe, and hydrogen transfer (H-transfer) under high pressure is of great importance to petroleum science, geoscience, planetary science, chemistry, and bioscience. It is the key step in the C–H circulation inside the earth, the reaction of organics and inorganics in giant planets, − and the synthesis of high-temperature superconductors . Typical H-transfer usually occurs via a hydrogen bond (H-bond), which can be tuned in very small steps but on very large energy scales under high pressure, hence changing the kinetics and even the thermodynamics of the H-transfer.…”

Synthesis of Perovskite-Type BiScO3 Ceramics and their Dielectric and Infrared Characterization

“…The synthesis process of the BiScO 3 samples of the perovskite phase was carried out using the URS-2 large reactive volume unit produced by the Technological Institute for Superhard and New Carbon Materials (TIS-NUM), Ministry of Science of the Russian Federation, Troitsk, Moscow region. 19 The initial powders used for the synthesis were tightly loaded into a cylindrical steel capsule with a diameter of 8 mm and a height of 5 mm, which was installed inside a toroidal pressure chamber made of calcite. Two resistive heaters made of a mixture of graphite and aluminum oxide were mounted on the upper and lower surfaces of the capsule.…”