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• A series of chitosan-derived ultramicroporous carbons were prepared using activating reagents-free method. • CNC-700 possesses excellent C 2 H 4 /C 2 H 6 molecular sieving performance. • High purity of C 2 H 4 can be produced via one-step adsorption–desorption process. • The good stability and scalability make CNC-700 a promising adsorbent for industrial applications. The selective separation of C 2 H 4 /C 2 H 6 pair is of paramount importance in the petrochemical industry, which is yet challenged by their similar polarities, shapes, and kinetic diameters. The use of carbonaceous adsorbents with molecular sieving capability holds great promise in achieving the desired selectivity and economically feasibility. However, such progress has been hindered by the typically wide pore size distribution observed in traditional carbons. Herein, we report a series of chitosan-based ultramicroporous carbons with C 2 H 4 /C 2 H 6 molecular sieving performance through an activating reagents-free method. The hydrothermal process of chitosan was initially employed to prepare condensed carbonaceous hydrochar rich in heteroatoms. The subsequent thermal etching led to the formation of sieving-based ultramicropores, stemming from the decomposition of heteroatoms and hot-shrinkage of pores at high temperature. The as-synthesized optimal CNC-700 sample achieved a high C 2 H 4 uptake of 32.3 cm3 (STP) g−1 and negligible C 2 H 6 adsorption at 298 K and 1.0 bar. The isosteric heat of C 2 H 4 on CNC-700 reached 34.5 kJ mol−1, significantly lower than other thermodynamically driven carbonaceous adsorbents. The fixed-bed breakthrough experiments further validated the efficient separation of equimolar C 2 H 4 /C 2 H 6 mixture under dynamic conditions. This work provides an important guideline to fabricate carbons with adjustable ultramicropore size derived from biomass for the highly effective separation of light hydrocarbons via molecular sieving. [ABSTRACT FROM AUTHOR]

[Display omitted] • DS was electrochemically synthesized in one step at industrial current density. • The strong electron-orbital hybridization promoted the decarboxylation reaction. • A second-order polynomial mathematical model was established for DS synthesis. • The optimal synthesis process for DS was determined by response surface methodology. Dimethyl sebacate is an essential organic chemical, yet its conventional high-temperature pyrolytic synthesis process is marked by complexity, energy intensity, environmental pollution, and volatile raw material supplies. Presently, electrochemical synthesis emerges as a promising, environmentally sustainable method for one-step dimethyl sebacate synthesis via anodic decarboxylation coupling with monomethyl adipate. However, the existing process falls short in achieving the desired selectivity and current efficiency, particularly when operating at high current densities, thus impeding its broader industrial adoption. This study, synergizing density functional theory computations with experimental methods, conducts a comprehensive multidimensional analysis of the electrochemical performance at high current densities across four distinct electrode types: Pt plate, RuO 2 /Ti, PbO 2 , and graphite electrodes. It underscores the strong electron-orbital hybridization between adsorbed monomethyl adipate and the platinum electrode, resulting in an enhanced propensity for electron transfer at the electrode interface and facilitating the decarboxylation of monomethyl adipate coupling into dimethyl sebacate. Subsequently, through single-factor experiments and response surface methodology, an exhaustive analysis of the various factors influencing the electrolysis process is conducted, including supporting electrolyte, current density, H 2 O content, neutralization, and monomethyl adipate concentration. The optimal electrolysis operation configuration offers a robust theoretical foundation and technical framework for the large-scale implementation of green, energy-efficient electrochemical synthesis technology for dimethyl sebacate in industrial settings. [ABSTRACT FROM AUTHOR]