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•NiP-based catalysts were obtained in situ from the different catalytic systems.•Full conversion of furfural was reached after 0.5−3 h at 250−350 °C.•77 % of 2-methylfuran selectivity ...was achieved over NiP-based catalysts in toluene.•Ethyl levulinate was obtained using NiP-based catalysts for the first time.
The present work is dedicated to the nickel phosphide based catalysts, containing particles, generated in situ in the reaction medium from the different catalytic systems. The present catalytic systems exhibited high activity in the hydroprocessing of furfural. Full conversion of furfural depending on conditions was reached after 0.5−3 hours of reaction at 250−350 °C. 2-methylfuran was obtained as a main product in toluene with the highest selectivity of 77 %. Ethyl levulinate and 2-methylfuran with selectivity of 40 % and 38 % respectively were obtained as main products in ethanol under different conditions. Different reaction medium and nickel phosphide precursors had an influence on the obtained phases of catalysts. Ni12P5 and Ni2P were obtained in toluene from oil-soluble precursors and Ni12P5 was obtained in ethanol from water-soluble precursors.
Anderson-type polyoxometalate (POM) catalysts were synthesized and applied for deep oxidative desulfurization of model fuel containing dibenzothiophene. O2 contained in air was used as oxidant under ...mild conditions. The influence of the nature of central heteroatom and that of the quaternary ammonium cation used on the conversion of DBT was investigated. For the first time to the best of our knowledge, the role of the solvent in aerobic oxidative desulfurization was investigated and the possible mechanism of DBT oxidation was suggested. It was shown that the key stage in the oxidation of the sulfur-containing compound is the generation of alkyl peroxides from the solvent.
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•Anderson-type POMs containing cobalt were applied for complete aerobic oxidation of sulfur containing compounds•Synthesized catalysts allow to achieve complete removal of DBT under mild conditions and short reaction time 1 h•The first time it was shown that the key stage in aerobic oxidation is the generation of alkyl peroxides from a solvent•Regenerated catalyst works without loss of activity for at least 5 cycles in DBT oxidation
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•The selective Ru catalysts based on non-acidic mesoporous materials were successfully synthesized.•A catalytic system to enhance aromatics through its transformation into cis-isomers ...of naphthenes was thoroughly investigated.•A correlation between catalytic activity and supports acidity was reported.•The highest cis/trans ratio of decalines can be achieved while the significant amount of tetralin remained in the system.
A series of Ru-contained catalysts based on mesoporous and micro-mesoporous supports synthesized for the selective hydrogenation of naphthalene and tetralin in n-hexadecane solution. The influence of the support – HMS, SBA-15 and ZSM-5/MCM-41, namely porous structure and acidity on the catalysts activity were thoroughly investigated. It was found that the supports acidity has a diminutive effect on the cis-decalin formation due to increased isomerization activity of cis-decalin to trans-decalin. It was shown that the amount of unconverted tetralin influenced the final cis/trans decalines ratio considerably. The effect of parameters such as temperature, hydrogen pressure and reaction time on conversion and selectivity to partially or fully hydrogenated products was investigated under 3–7 MPa H2, 220–320 °C and 0.5–3 h. It provides a practically fully naphthalene conversion and a high cis-decalin selectivity.
Unsupported nickel phosphide catalyst containing Ni2P phase was applied in the hydrodeoxygenation of ethyl levulinate in ethanol medium for the first time. The obtained catalyst was investigated by ...XRF, XRD, NH3–TPD, XPS and TEM techniques. γ-valerolactone and ethyl valerate were obtained as the hydrodeoxygenation products. Varying the temperature and the reaction time it was possible to obtain these products with high selectivity. γ-valerolactone was selectively formed at 200–250 °C and ethyl valerate was selectively formed at temperatures of 300–350 °C. Increase in reaction time was contributed to ethyl valerate formation. The highest selectivity of ethyl valerate was 100% at full ethyl levulinate conversion at 350 °C after 6 h. 100% γ-valerolactone selectivity was reached at low conversion of ethyl levulinate. The highest yield of γ-valerolactone reached 41.7% after 6 h of the reaction at 250 °C. The selectivity of γ-valerolactone was 86.9% and the conversion of ethyl levulinate was 48.0%.
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•The HDO of ethyl levulinate in ethanol was investigated over unsupported Ni2P.•γ-valerolactone and ethyl valerate was obtained in the HDO of ethyl levulinate.•Ethyl valerate was produced with 100% selectivity at full conversion at 350 °C.•The high activity of the nickel phosphide catalyst is remaining after 10 cycles.
Dehydrogenation processes play an important role in the petrochemical industry. High selectivity towards olefins is usually hindered by numerous side reactions in a conventional cracking/pyrolysis ...technology. Herein, we show recent studies devoted to selective ethylene production via oxidative and non-oxidative reactions. This review summarizes the progress that has been achieved with ethane conversion in terms of the process effectivity. Briefly, steam cracking, catalytic dehydrogenation, oxidative dehydrogenation (with CO2/O2), membrane technology, and chemical looping are reviewed.
Neuronal activity influences genes involved in circuit development and information processing. However, the molecular basis of this process remains poorly understood. We found that HDAC4, a histone ...deacetylase that shuttles between the nucleus and cytoplasm, controls a transcriptional program essential for synaptic plasticity and memory. The nuclear import of HDAC4 and its association with chromatin is negatively regulated by NMDA receptors. In the nucleus, HDAC4 represses genes encoding constituents of central synapses, thereby affecting synaptic architecture and strength. Furthermore, we show that a truncated form of HDAC4 encoded by an allele associated with mental retardation is a gain-of-function nuclear repressor that abolishes transcription and synaptic transmission despite the loss of the deacetylase domain. Accordingly, mice carrying a mutant that mimics this allele exhibit deficits in neurotransmission, spatial learning, and memory. These studies elucidate a mechanism of experience-dependent plasticity and define the biological role of HDAC4 in the brain.
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► HDAC4 is a histone deacetylase that shuttles between the nucleus and cytoplasm ► HDAC4 associates with neuronal chromatin and TFs in an NMDA receptor-dependent manner ► HDAC4 represses genes essential for synaptic function ► HDAC4 regulates synaptic transmission and memory without deacetylating histones
Neuronal activity triggers the nuclear export of HDAC4, which in turn induces genes that regulate circuit development and information processing. Misregulation of this pathway in mice impairs neurotransmission, spatial learning, and memory.
Synaptic excitation mediates a broad spectrum of structural changes in neural circuits across the brain. Here, we examine the morphologies, wiring, and architectures of single synapses of projection ...neurons in the murine hippocampus that developed in virtually complete absence of vesicular glutamate release. While these neurons had smaller dendritic trees and/or formed fewer contacts in specific hippocampal subfields, their stereotyped connectivity was largely preserved. Furthermore, loss of release did not disrupt the morphogenesis of presynaptic terminals and dendritic spines, suggesting that glutamatergic neurotransmission is unnecessary for synapse assembly and maintenance. These results underscore the instructive role of intrinsic mechanisms in synapse formation.
•Hippocampal circuits can develop independently of excitatory neurotransmission•Synaptic release of glutamate is unnecessary for morphogenesis of dendritic spines•Synapses assembled in the absence of activity are structurally mature
Sando et al. investigate the architectures of neural circuits in the murine hippocampus that develop in virtually complete absence of glutamatergic neurotransmission. They show that synaptic excitation is unnecessary for assembly of stereotyped connectivity and structurally mature synapses.
The effect of cyclodextrins on the activity and selectivity of a catalytic system based on rhodium nanoparticles stabilized by polyacrylic acid (PAA) in the hydrogenation of phenol in aqueous ...solution and ionic liquid was reported. It was found that the reaction medium and the nature of the cyclodextrin (CD) essentially affect the rate of reaction and the distribution of reaction products. The use of the system based on rhodium nanoparticles stabilized by cyclodextrins makes it possible to rapidly and efficiently prepare cyclohexanone from phenol with yields up to 100% under relatively mild conditions (1h; T=80°°C, p(H2)=10–40bars).
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•Rh nanoparticles/poly(acrylic) acid is the active catalyst for phenol hydrogenation.•The presence of cyclodextrin favors the cyclohexanone formation.•The inclusion complex formation has a crucial role for the cyclohexanone selectivity.•The use of polymer-bound cyclodextrin allows to obtain 100% cyclohexanone selectivity.
The first example of an application of porous aromatic frameworks (PAFs) in synthesis of catalysts for oxidative desulfurization was described. The mesoporous aromatic framework with a diamondlike ...structure was modified with tungsten and molybdenum carbonyls, and synthesized catalysts were successfully used for low-temperature oxidation of organic sulfides. The obtained materials were characterized by low-temperature nitrogen adsorption/desorption, transmission electron microscopy, atomic emission spectroscopy, and X-ray photoelectron spectroscopy techniques. It was shown that the polymer did not undergo oxidation and retained its structure in the presence of hydrogen peroxide and tert-butyl hydroperoxide. The catalysts possessed high activity because of the hydrophobic nature of the carrier and their high surface area.
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