This Perspective highlights recent developments in methane conversion into different hydrocarbons and C₁-oxygenates. Our analysis identified possible directions for further research to bring the above approaches to a commercial level.

Continuous synthesis of diethyl carbonate from ethanol and CO ₂ at the reaction equilibrium level is possible at low contact times.

In this Review, all known chemical methods for the conversion of renewable resources into benzenoid aromatics are summarized. The raw materials that were taken into consideration are CO₂; lignocellulose and its constituents cellulose, hemicellulose, and lignin; carbohydrates, mostly glucose, fructose, and xylose; chitin; fats and oils; terpenes; and materials that are easily obtained via fermentation, such as biogas, bioethanol, acetone, and many more. There are roughly two directions. One much used method is catalytic fast pyrolysis carried out at high temperatures (between 300 and 700 °C depending on the raw material), which leads to the formation of biochar; gases, such as CO, CO₂, H₂, and CH₄; and an oil which is a mixture of hydrocarbons, mostly aromatics. The carbon selectivities of this method can be reasonably high when defined small molecules such as methanol or hexane are used but are rather low when highly oxygenated compounds such as lignocellulose are used. The other direction is largely based on the multistep conversion of platform chemicals obtained from lignocellulose, cellulose, or sugars and a limited number of fats and terpenes. Much research has focused on furan compounds such as furfural, 5-hydroxymethylfurfural, and 5-chloromethylfurfural. The conversion of lignocellulose to xylene via 5-chloromethylfurfural and dimethylfuran has led to the construction of two large-scale plants, one of which has been operational since 2023.

The direct synthesis of diethyl carbonate (DEC) from ethanol and carbon dioxide over Ce_0.8Zr_0.2O₂ catalysts was investigated in continuous mode at atmospheric pressure. Three main parameters, namely molar ratio of ethanol/CO₂, flux and temperature, have significant influence on the formed DEC amount and were studied systematically. With 32 mmol_DEC L⁻¹ _cat h⁻¹ achieved at ambient pressure, an ethanol/CO₂ molar ratio of 3 and a temperature of 100 °C the continuous approach offers a higher productivity compared to batch reactions, normally performed in autoclaves under much higher pressure. Moreover, in order to shift the equilibrium to promote the formation of DEC, four inorganic porous membranes, (i) MFI zeolite, Si/Al ratio ∼57; (ii) MFI zeolite, Si/Al ratio ∼270; (iii) LTA (NaA) zeolite; and (iv) a microporous carbon membrane, have been applied for product removal in a catalytic membrane reactor. A relationship between the amount of removed water achieved by the membranes and the enhancement of formed DEC amount was found. The productivity can be increased to 47 mmol_DEC L⁻¹ _cat h⁻¹ using an MFI-57 membrane.