Compared with ethanol, higher alcohols have the advantages of high cetane number, high energy density, non corrosiveness to engine parts, immiscibility with water, good stability, and other advantages as fuel or fuel additive directly. The conversion of fermentation bioethanol into more valuable higher alcohols has attracted widespread attention. This paper reviewed the research progress of bioethanol to higher alcohols at home and abroad in recent years, including the research and development of metal oxides, hydroxyapatite (HAP) and supported metal catalysts. Finally, the current challenges and future research trends of bioethanol to higher alcohols are summarized and prospected, pointing out that the development of multifunctional catalysts is the focus of future research, and Aldol condensation is an effective strategy to further improve the conversion and selectivity of bioethanol to higher alcohols.

Aromatic hydrocarbons, especially monocyclic aromatic hydrocarbons such as benzene, toluene, and xylene (BTX), are important basic raw materials in the chemical industry, which are mainly derived from the catalytic reforming and thermal cracking of fossil fuels. The co-catalytic pyrolysis of biomass and plastic to produce aromatics has the advantages of high efficiency, environmental protection, low cost, and high selectivity. It can solve the problems of pyrolysis products such as high oxygen content, low aromatics yield, and low selectivity, which are caused by the characteristics of biomass rich in oxygen and poor in hydrogen. This article reviewed the research progress of co-catalytic pyrolysis of biomass and plastics to prepare aromatic compounds. Firstly, the types of raw materials for co-catalytic pyrolysis were introduced, and then the co-catalytic pyrolysis catalysts were emphasized. The reaction mechanisms of co-catalytic pyrolysis of biomass and plastics, such as the synthesis of dienes and hydrocarbon pool synergy were summarized. Finally, the future research focus and development direction of co-catalytic pyrolysis of biomass and plastics were proposed, which is developing the highly active and stable modified molecular sieve catalysts in order to improve the aromatics yield.

Chemical conversion of greenhouse gas CO2 into value-added oxygenates such as ethanol, acetic acid, propanal, propionic acid, butanol, etc. is challenging due to the complexity of C−C coupling and the uncontrollable bonding. In this review, recent research progresses on the synthesis of multi-carbon oxygenates from CO2 in fixed bed reactor are provided. Firstly, the reaction mechanisms of CO2 hydrogenation are summarized. Then, the potential catalysts applied in one-step or tandem CO2 hydrogenation, dry reforming with light hydrocarbons and hydroformylation were introduced over metal carbides, alkali metal modified single or binary metal catalysts such as Cu, Fe, Co, Rh, etc. The reaction mechanism over different catalysts were further elaborated. Finally, the problems and outlook are discussed.

The costly separation of 1,2-propanediol (1,2-PDO), an unavoidable byproduct in the hydrogenation of dimethyl oxalate (DMO), significantly hampers the economic viability of coal-to-ethylene glycol (EG) technology. To address this challenge, the formation mechanism of the side product 1,2-PDO on the Cu(111) and Cu2O(111) surfaces during DMO hydrogenation was investigated, which focused on the active sites of copper catalyst and the dominant pathway through density functional theory calculation. The thermodynamics of each elementary step and the adsorption behavior of various species involved in the reaction network along with the local density of states and charge density difference were systematically analyzed. The results indicate that 1,2-PDO is generated more favorably on the Cu2O(111) surface than that on the Cu(111) surface, owing to the Lewis acid-base pairs, i.e. \begin{document}${\rm{Cu}}_{{\rm{us}}}^{+} $\end{document} and \begin{document}${\rm{O}}_{{\rm{suf}}}^- $\end{document} sites, present on the Cu2O(111) surface, which strengthens the binding of reactants, products, and reaction intermediates to the substrate. EG reacts primarily with methanol (MeOH) to form 1,2-PDO through Guerbet alcohol condensation reaction through three consecutive steps: alcohol dehydrogenation, aldol condensation, and unsaturated aldehyde hydrogenation. The \begin{document}${\rm{O}}_{{\rm{suf}}}^- $\end{document} sites promote the dehydrogenation of alcohols into aldehydes, the generation of enolates during aldol condensation and the hydrogenation of unsaturated aldehydes, while the \begin{document}${\rm{Cu}}_{{\rm{us}}}^{+} $\end{document} sites are responsible for the C–C coupling reaction. These findings may shed light on the mechanism of 1,2-PDO formation over Cu catalyst and provide fundamental knowledge for the development of more efficient catalysts and process optimization.

Lean methane from abandoned coal mines or drainage gas with methane concentration of 1%−3% is in general directly discharged into the atmosphere due to the lack of appropriate technology, which has caused serious environmental concerns due to its high global warming potential. While direct thermal oxidation of ultra-low methane in a flow reversal reactor offers an attractive solution, it poses challenges such as potential explosions and unstable combustion flames. Elucidating the dynamic behavior of thermal oxidation of ultra-low methane in a flow reversal reactor is the basis for practical application. To this end, autothermal operation boundary of a pilot-scale thermal flow reversal reactor was examined and the effects of hot gas withdrawal on the behavior of flow reversal reactor was deeply studied. It was found that autothermal operation can be achieved with a methane content of over 0.2% and heat can be recovered if methane content is over 0.5%. Withdrawal of hot air has a significant impact on the dynamic behavior of the reactor: maximum bed temperature at the pseudo-steady state without hot gas extraction keeps almost constant with methane concentration varying in 0.5%−3.0%; whereas for heat recovery by hot gas withdrawal, the maximum bed temperature increases with the increase of the amount of hot gas extracted, and the allowable hot gas exported from the reactor increases nearly linearly from 12.5% to 32% as the methane content increases from 0.5% to 3.0%. Furthermore, the appropriate switching time decreases with the increase of the amount of hot gas withdrawn; for most cases, reversing flow direction at a time interval of 30−50 s can ensure complete methane conversion and stable bed temperature. Thus, it may be concluded that lean methane (1%−3%) can be mitigated by thermal oxidation without worrying about the bed temperature runaway or explosion.

A stable metal-organic framework (MOF), MIL-101(Fe), was successfully synthesised using a solvothermal method and employed as a novel photocatalyst for degrading crude oil in oilfield wastewater. Through optimisation of reaction conditions, the following optimal parameters were determined: a dark reaction time of 30 min, a light reaction time of 30 min, a pH of 5.5, a catalyst amount of 150 mg/L, and a reaction temperature of 303.15 K. Under these reaction conditions, an impressive removal of 94.73% was achieved. This study represents the first application of Fe-based MOFs in the photocatalytic degradation of oilfield wastewater. MIL-101(Fe) notably demonstrated excellent stability under mild acid conditions and can be efficiently recycled. These findings offer valuable insights into using MIL-101(Fe) as a promising material for industrial applications in removing crude oil from oil-polluted water through photocatalytic degradation.