Industrial Chemistry & Materials最新文献

To address the critical challenge of balancing ultralow dielectric constant (k) with low coefficient of thermal expansion (CTE) in high-frequency electronic applications, this study develops a series of tri-armed benzocyclobutene (BCB)-based resins via rational molecular design. Five functional monomers (Ph-BCB, Ph-ene-BCB, Ph-yne-BCB, TPA-yne-BCB, TPB-yne-BCB) were synthesized through Suzuki, Heck, and Sonogashira coupling reactions, followed by thermal curing to form crosslinked polymers. The introduction of branched architectures and rigid conjugated cores effectively enhanced free volume fraction while suppressing molecular chain mobility, achieving synergistic optimization of dielectric and thermomechanical properties. The cured resins exhibited exceptional performance: dielectric constants as low as 1.83 (TPA-yne-BCB) at 1 kHz, dielectric loss below 0.0015, and CTE values ranging from 19.23–34.63 ppm °C⁻¹, closely matching copper (16 ppm °C⁻¹). The SAXS and WAXS analyses confirmed that enlarged free volume and reduced polarization from optimized topology were key to low-k performance. Additionally, the materials demonstrated outstanding thermal stability (5% weight loss >500 °C), high mechanical strength (elastic modulus up to 10 GPa), and hydrophobicity (water absorption <2%). This work provides a groundbreaking strategy for designing high-performance dielectric materials for 5G millimeter-wave packaging, flexible electronics, and 3D heterogeneous integration.

Keywords: Benzocyclobutene; Ultralow dielectric constant; Low thermal expansion; Tri-armed monomer; Branched polymers.

With the development of high-frequency communication technologies, polyimide (PI) materials with a low dielectric constant (D_k) and low dissipation factor (D_f) are urgently needed to reduce signal crosstalk and other transmission problems. The introduction of a trifluoromethyl group is a common strategy to reduce D_k and D_f, but the bulky trifluoromethyl group would diminish stacking density and consequently lead to inferior mechanical properties. Herein, a novel diamine monomer, 2,3,4,5,6-pentafluororo-3,5-bis(4-aminophenoxy)-1,1-biphenyl (5FBODA), was designed and synthesized using simple reactions. Subsequently, fluorinated diamine and dianhydride were copolymerized with 5FBODA to obtain a series of fluorinated polyimide (FPI) with excellent dielectric properties and good mechanical performances, particularly high elongation at break. The pentafluorophenyl side group showed an obvious electron-withdrawing effect and made the charge of the structure more balanced, which reduced the molecular polarization rate and charge concentration to some extent, significantly helping in reducing D_k at high frequency. As the 5FBODA content increased, the large lateral group restricted the movement of the main chain, constrained the dipole polarization, thereby effectively diminishing their D_f. Moreover, when 20–30% 5FBODA was added, the pentafluorophenyl side group increased the intermolecular forces, thereby enhancing the elongation at break while maintaining good thermal properties. These FPIs exhibited remarkable advantages for advanced microelectronic packaging applications, providing an innovative solution for the development of next-generation high-performance electronic materials.

Keywords: Wafer level packaging; Fluorinated polyimide; Low dielectric; High toughness.

All-solid-state sodium-ion batteries (ASIBs) have good application prospects due to the high energy density, high safety and long lifetime. The excessive use of ASIBs in the near future will inevitably lead to the generation of spent batteries, contributing to environmental pollution and resource waste. In this work, we utilize three types of green solvents—ionic liquids (ILs), deep eutectic solvents (DESs), and low-melting mixture solvents (LoMMSs)—to recover both the cathode and solid electrolyte from ASIBs, as well as the cathode and electrolyte from lithium-ion batteries (LIBs). Results show that the leaching efficiency of Na from the cathode and solid electrolyte of ASIBs by LoMMSs could respectively reach as high as 92.8% and 96.7% at a mild temperature of 80 °C, which is higher than that in ILs and DESs. The highest metal leaching efficiency from ASIBs is similar to that from LIBs. Both LoMMSs and leachate are non-flammable when exposed to a high-temperature torch. In addition, 70 anti-solvents are screened to recover metal from the leachate at room temperature, with acetone yielding the highest precipitation efficiency of 92.0%.

Keywords: Green solvents; Rechargeable batteries; Solid waste; Green chemistry; Physical properties; Anti-solvents.

The presence of sulfur compounds, particularly SO₂, is known to significantly degrade the performance of metal-based catalysts, posing a significant challenge in CO₂ hydrogenation reactions. In this study, we systematically investigate the impact of SO₂ on Cu–ZnO–Al₂O₃ catalysts for CO₂ hydrogenation to elucidate the deactivation mechanisms. Our findings reveal that SO₂ adsorption leads to the formation of surface sulfate and sulfite species, which effectively block active sites, impeding the adsorption and activation of reactants. Moreover, SO₂ exposure inhibits CO desorption, further compromising catalytic efficiency. In parallel, progressive sulfidation of Cu and ZnO results in the formation of catalytically inactive CuS, Cu₂S, and ZnS phases, ultimately leading to complete catalyst deactivation. These results highlight the dual role of sulfur species in both surface passivation via sulfates/sulfites deposition and irreversible structural transformation via sulfidation. Our study provides new insights into the SO₂-induced catalyst deactivation in CO₂ hydrogenation and offers a theoretical foundation for enhancing CO₂ hydrogenation reactions, with implications for optimizing environmentally sustainable catalytic systems in industrial applications.

Keywords: CO₂ hydrogenation; The role of SO₂; Deactivation; Phase transition; RWGS.

Electrochemical CO₂ reduction (CO₂RR) to synthesize multicarbon products is a critical route for sustainable CO₂ utilization, yet achieving high selectivity and current density simultaneously remains challenging. While enhancing *CO coverage on catalysts is pivotal for promoting C–C coupling, the dynamic competition between intermediate enrichment and microenvironment regulation necessitates innovative strategies. Here, we employ surface ligand engineering to construct a tunable hydrophobic microenvironment on Cu₂O catalysts, using imidazolium-based ionic liquids with alkyl side chains of varying lengths. The optimized OMIm-Cu₂O catalyst achieves a C₂₊ selectivity of 63.3% in alkaline media and 30.7% in acidic media. Mechanistic studies reveal that hydrophobic long-chain ligands elevate local *CO concentration, facilitating efficient C–C coupling. This work highlights microenvironment modulation as a viable pathway to bridge the gap between high efficiency and industria–current–density performance in CO₂RR.

Keywords: Electrochemical CO₂ reduction; C₂₊ product selectivity; Copper-based catalysts; *CO concentration.

Silane (SiH₄), a critical electronic specialty gas for semiconductor and renewable energy technologies, is conventionally produced via trichlorosilane (TCS) disproportionation. This study introduced an innovative route utilizing dichlorosilane (DCS), a by-product of the Siemens process, and comparative analysis was also conducted between the reactive distillation (RD) and fixed-bed reactor (FBR) approaches. Process simulations demonstrate that, given TCS as the feedstock and the same silane output, the RD approach reduces energy consumption to <25% of conventional FBR systems by overcoming thermodynamic equilibrium through continuous product removal. When employing the RD approach, the energy consumption using DCS as the feedstock can be reduced to approximately 35% or 22% of that when TCS is utilized, depending on whether the main by-product is silicon tetrachloride (STC) or TCS. This improvement stems from the superior thermodynamic and kinetic properties of DCS disproportionation. The optimal process configuration depends on whether the silane production process is integrated with the Siemens process or a grassroots facility.

Keywords: Silane; Dichlorosilane; Reactive distillation; Disproportionation; Process simulation.

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Amine-functionalized Mg₂(dobpdc) sorbents are prepared and studied systematically using three amines of different sizes: N,N′-dimethylethylenediamine (m-2-m), tetraethylenepentamine (TEPA), and poly(ethyleneimine) (PEI), in order of increasing size. A prototypical amine-appended Mg-based metal–organic framework, m-2-m-Mg₂(dobpdc), is tested under dry direct air capture (DAC) conditions at cold temperatures (<25 °C) with the objective of increasing the CO₂ capture fraction by shifting the step pressure in the isotherm to lower pressures. We observe that the theoretical amine efficiency (one CO₂ to one diamine) could not be achieved due to the failure of the established amine insertion mechanism. In contrast, TEPA-impregnated Mg₂(dobpdc) shows a significant increase in its CO₂ adsorption capacity under humid conditions (3.9 mmol g⁻¹ and 0.33 amine efficiency at 25 °C) compared to dry conditions (0.54 mmol g⁻¹), aided by hydration of amines by water at elevated relative humidities (≥50% RH), which frees some amine chains and alleviates diffusion resistances along the MOF pore. On the other hand, both branched and linear PEI-impregnated Mg₂(dobpdc) samples undergo morphological degradation after humid adsorption/desorption cycles, likely due to the ineffective protection of the open metal sites in the MOF from water by the higher molecular weight amines. While degradation of PEI-impregnated Mg₂(dobpdc) raises a concern about the overall stability of poly(amine)-impregnated Mg₂(dobpdc) materials, the TEPA-impregnated sample shows stable performance over 20 humid sorption/desorption cycles with N₂ purge for desorption and over 8 humid cycles with vacuum desorption.

Keywords: Direct air capture; Humidity; Metal organic frameworks; DAC; Hydration; Degradation.

The synthesis of new and potentially “green” solvents and other small molecules/intermediates from glycerol and associated derivatives is promising for expanding glycerol valorization. Previously, we showed that eliminating H-bonding reduces solvent–solvent interactions and increases CO₂ solubility in 1,3-diether-2-ketones compared to 1,3-diether-2-alcohols based on glycerol skeletons. Further exploration of glycerol-derived 1,3-diether-2-propanol compounds into corresponding 1,3-diether-2-alkenes can yield valuable insights into structure–property relationships as well as new chemical intermediates. In the current work five symmetric glycerol-derived (E/Z)-1,3-diether-2-alkenes were synthesized: 1,3-dimethoxyprop-1-ene ([M, A, M]), 1,3-diethoxyprop-1-ene ([E, A, E]), 2,5,9,12-tetraoxatridec-6-ene ([ME, A, ME]), 1,3-bis(2,2,2-trifluoromethoxy)prop-1-ene ([F, A, F]), and prop-1-ene-1,3-diylbis(oxy)bis(methylene)dibenzene ([Bn, A, Bn]), using a three-step strategy starting from epichlorohydrin. All compounds were purified using thorough distillation and drying methods. The E : Z ratio in all products was close to 1 : 1. Thermophysical properties of the synthesized (E/Z)-1,3-diether-2-alkenes (e.g., density, refractive index, viscosity) were measured over the range of T = 293.15–333.15 or 343.15 K. CO₂ absorption capacities (Henry's constants) of [F, A, F] were measured at T = 303.15, 318.15, 333.15, and 348.15 K and pressures in the range of P = 2–10 atm. Density, viscosity, vapor pressure, enthalpy of vaporization, and dipole moment were also calculated for each compound. Additionally, it was demonstrated that the CC bond remains accessible for further reactions and can undergo bromination and thus may also have applications as intermediates for more complex molecules that are based on glycerol skeletons.

Keywords: Glycerol; Green solvents; CO₂ absorption; Symmetric alkenes; Platform molecules.

Dual functional materials (DFMs) have the potential to improve the process of CO₂ capture and subsequent conversion to fuel. Materials consisting of Na and Ru supported on alumina have been investigated for cyclic direct CO₂ air capture and conversion to CH₄. We have studied the regeneration conditions, specifically the target temperature and gas composition (inert or hydrogen-containing gas) during heating. The effect of air humidity and Na loading on the effectiveness of CO₂ capture has also been assessed. Finally, the DFMs have been successfully implemented as structured contactors with a low pressure drop, which is an unavoidable requirement for practical application.

Keywords: Dual functional materials; Direct air CO₂ capture; Methanation; Monoliths.