Hydrothermal synthesis of long-chain hydrocarbons up to C24 with NaHCO3-assisted stabilizing cobalt

Abiotic CO2 reduction on transition metal minerals has been proposed to account for the synthesis of organic compounds in alkaline hydrothermal systems, but this reaction lacks experimental support, as only short-chain hydrocarbons (<C5) have been synthesized in artificial simulation. This presents a question: What particular hydrothermal conditions favor long-chain hydrocarbon synthesis? Here, we demonstrate the hydrothermal bicarbonate reduction at ∼300 °C and 30 MPa into long-chain hydrocarbons using iron (Fe) and cobalt (Co) metals as catalysts. We found the Co0 promoter responsible for synthesizing long-chain hydrocarbons to be extraordinarily stable when coupled with Fe−OH formation. Under these hydrothermal conditions, the traditional water-induced deactivation of Co is inhibited by bicarbonate-assisted CoOx reduction, leading to honeycomb-native Co nanosheets generated in situ as a new motif. The Fe−OH formation, confirmed by operando infrared spectroscopy, enhances CO adsorption on Co, thereby favoring further reduction to long-chain hydrocarbons (up to C24). These results not only advance theories for an abiogenic origin for some petroleum accumulations and the hydrothermal hypothesis of the emergence of life but also introduce an approach for synthesizing long-chain hydrocarbons by nonnoble metal catalysts for artificial CO2 utilization.

Renewable Hydrocarbon Production via Rapeseed Oil Hydrotreatment Over Palladium Catalysts

The effect of SiO2-Al2O3 (Pd5%/SA), activated carbon (Pd5%/C) and Al2O3 (Pd5%/A) supported palladium (5%) catalysts on renewable hydrocarbon synthesis via rapeseed oil hydrotreatment was investigated. The hydrotreatment experiments were carried out in solvent free medium under initial H2 pressure 100 bar and at 340 °C temperature for 120 min using catalyst amount 5%. Gas chromatography-mass spectrometry (GC/MS) analysis were used for estimation of hydrocarbon content in the obtained samples. Pd5%/SA catalyst provided complete conversion of rapeseed oil into marketable liquid renewable hydrocarbons without presence of oxygen containing substances under studied hydrotreatment conditions. Moreover, all tested Pd catalysts gave narrow range of linear saturated hydrocarbons (n-C15-C19). Pd5%/C and Pd5%/A catalysts gave partial feedstock conversion into hydrocarbons even in long residence time. Overall liquid hydrocarbon yields were from 55.3% to 82.3%.

Direct Fixation of Atmospheric CO2 towards Chemical Synthesis of Fuel Hydrocarbon

We have reported that fuel hydrocarbon was chemically synthesized from CO2 and activated water. In this report, we show the direct evidence of CO2 fixation from air. CO2 in the air is composed of about 99 % 12C, about 1% 13C, and about one trillionth radioisotope 14C. The extremely trace amount of 14C was measured with liquid scintillation counter by following beta-decay. The newly synthesized hydrocarbon revealed 14.6 dpm/gC. These facts clearly demonstrate direct fixation of atmospheric CO2 toward hydrocarbon synthesis.

Hydrocarbons and degassing processes of Saturn’s satellite Titan

Research subject and methods. The paper presents a review of available information on the atmosphere of Titan and its surface, necessary for the development of concepts of hydrocarbon formation, including the natural hydrocarbon synthesis, formation of prebiogenic states and origin of life. The presence of vast reserves of abiogenic hydrocarbons on Titan is extremely important for the theory of hydrocarbon genesis on the Earth, since any concept of naphthogenesis claiming to be a consistent explanation of the entire set of available facts must take into account the possibility of abiogenic formation of large accumulations of hydrocarbons.Results. It was shown that the hydrocarbon diversity of the atmosphere and surface of Titan is provided by the inflow of endogenous methane. Degassing processes on Titan are characterized by specific forms due to their flow through a liquid medium: 1) “gas-lifting degassing” forming numerous small depressions with increased fluid levels and, possibly, being the cause of “magic islands” in the sea of Ligeia; 2) limnological emissions of gaseous methane, followed by intensive cloud formation, the development of methane storms and large amounts of precipitation.Conclusions. It is concluded that the presence of active degassing processes on Titan in combination with the emerging models of its internal structure contribute to clarifying the previously proposed scheme of primary natural hydrocarbon synthesis in the depths of Titan.

EXISTING TECHNOLOGIES AND PROSPECTS FOR THE DEVELOPMENT OF SYNTHESIS OF HYDROCARBONS WITH THE USE OF COBALT CATALYSTS

Fischer-Tropsch synthesis is the main process for the production of synthetic hydrocarbons. The raw material of the process is a mixture of CO and H2, called synthesis gas. The process is carried out using catalysts based on cobalt or iron, supported on carriers of various nature. The composition of the resulting product depends on the process conditions and the catalyst used. Hydrocarbon synthesis technologies are developed and introduced into production by both foreign and some Russian companies.

INFLUENCE OF MANGANESE ON FORMATION OF ACTIVE PHASE OF COBALT CATALYST OF HYDROCARBON SYNTHESIS

The active phase and catalytic properties of cobalt catalysts of Fischer-Tropsch synthesis promoted with manganese and prepared by impregnation were studied. KSKG silica gel having a monodisperse structure with an average pore diameter of 12–16 nm was used as a support. The cobalt content in the obtained samples was 20.8-21.8 wt.%, manganese content was 0.5–2 wt.%. The structural characteristics of the catalysts were investigated by X-ray diffraction, transmission electron microscopy, temperature-programmed reduction and temperature-programmed hydrogen desorption. The catalytic activity and selectivity of the samples in the process of hydrocarbon synthesis were researched in the flow mode at a pressure of 0.1 MPa, at a Gas Hourly Space Velocity (GHSV) of 100 h–1, at the temperatures of 150–220 °C and a ratio of CO to hydrogen in synthesis gas of 2:1. Preliminary reduction of catalysts was carried out with hydrogen at a temperature of 400 °C. In the composition of the studied samples with manganese the formation of solid solutions of metals such as xCo3O4–(1–x)Mn3O4 was confirmed. It is shown that the reduction process of Co3O4 is determined by the composition and structure of solid solutions of components that are hard-to-recover compounds. The features of the promoting action of manganese depending on the concentration are determined. The introduction of 0.5–2 wt.% manganese allows to regulate the composition and microstructure of cobalt oxide compounds, the properties of metallic Co, increases the catalytic characteristics: activity, selectivity for C5+ and reduces the yield of methane. It is shown how, depending on the content of the metal additive, the manifestations of the structural (at a concentration of 0–1 wt.%) or electronic (at a concentration of 2 wt.%) promoting action of manganese increase. The optimum concentration of manganese is 1 wt.%. The catalyst is characterized by the minimum average size of crystallites, the highest value of the specific surface of cobalt metal and the maximum catalytic indicators.