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By reflecting on the history and environmental impact of conventional biorefining, such as kraft pulping, we aim to explore important questions about how natural polymers can be more sustainably sourced to develop bio-products and reduce reliance on plastics. Since the Industrial Revolution, chemical pulping processes have enabled the mass production of cellulosic products from woody biomass. Kraft pulping, which dominates within modern pulp and paper mills, has significantly contributed to environmental pollution and carbon emissions due to sulfurous byproducts and its high water and energy consumption. While chemical pulping technologies have advanced over time, with improvements aimed at enhancing sustainability and economic feasibility, conventional biorefineries still face challenges related to biomass conversion efficiency and environmental impact. For example, efforts to fully utilize wood resources, such as isolating lignin from black liquor, have made limited progress. This perspective provides a thoughtful examination of the growth of chemical pulping, particularly the kraft process, in the production of consumer goods and its environmental consequences. It also presents key insights into the bottlenecks in developing truly sustainable biomass conversion technologies and explores potential alternatives to traditional chemical pulping. [ABSTRACT FROM AUTHOR]

BackgroundBiomass pretreatment using certain ionic liquids (ILs) is very efficient, generally producing a substrate that is amenable to saccharification with fermentable sugar yields approaching theoretical limits. Although promising, several challenges must be addressed before an IL pretreatment technology can become commercially viable. One of the most significant challenges is the affordable and scalable recovery and recycle of the IL itself. Pervaporation (PV) is a highly selective and scalable membrane separation process for quantitatively recovering volatile solutes or solvents directly from non-volatile solvents that could prove more versatile for IL dehydration.ResultsWe evaluated a commercially available PV system for IL dehydration and recycling as part of an integrated IL pretreatment process using 1-ethyl-3-methylimidazolium acetate ([C2C1Im][OAc]) that has been proven to be very effective as a biomass pretreatment solvent. Separation factors as high as 1500 were observed. We demonstrate that >99.9 wt% [C2C1Im][OAc] can be recovered from aqueous solution (≤20 wt% IL) and recycled five times. A preliminary technoeconomic analysis validated the promising role of PV in improving overall biorefinery process economics, especially in the case where other IL recovery technologies might lead to significant losses.ConclusionsThese findings establish the foundation for further development of PV as an effective method of recovering and recycling ILs using a commercially viable process technology.

Using Ce(III) as both a representative lanthanide and actinide analog, the ability of mixtures of acidic and basic azoles to allow direct access to homoleptic N‐donor f‐element complexes in one pot reactions from hydrated salts as starting materials was examined by reacting mixtures of 4‐amino‐1,2,4‐triazole (4‐NH2‐1,2,4‐Triaz), 5‐amino‐tetrazole (5‐NH2‐HTetaz), and 1,2,3‐triazole (1,2,3‐HTriaz) in 1 : 1 and 1 : 3 ratios with CeCl3 ⋅ 7H2O, [C2mim]3[CeCl6] ([C2mim]+=1‐ethyl‐2‐methylimidazolium), and Ce(NO3)3 ⋅ 6H2O. Although unsuccessful in our goal, structural analysis revealed that neutral 4‐NH2‐1,2,4‐Triaz is structure directing via η2μ2κ2 bridging, with the formation of the dinuclear complexes [Ce2Cl2(μ2‐4‐NH2‐1,2,4‐Triaz)4(H2O)8]Cl4 ⋅ 4H2O, [Ce2(μ2‐4‐NH2‐1,2,4‐Triaz)4(4‐NH2‐1,2,4‐Triaz)2(Cl)6], and [4‐NH2‐1,2,4‐HTriaz][Ce2(μ2‐4‐NH2‐1,2,4‐Triaz)2(μ2‐NO3)(NO3)6(H2O)2]. When the synthetic conditions favored hydrolysis, the hexanuclear Ce(III) complex [Ce6(μ3‐O)4(μ3‐OH)2(μ3‐Cl)2(Cl)6(μ2‐4‐NH2‐1,2,4‐Triaz)12] ⋅ 7H2O was isolated. This unexpected hydrolysis product represents the first example of a high nuclearity lanthanide complex where all Ln atoms are pairwise connected through 12 N‐donor ligands or 12 neutral bridging ligands of any type, a rare example of incorporation of non‐oxo coordinating anions in the M6X8 core, and the first reported Ce(III) hexanuclear complex of this type. [ABSTRACT FROM AUTHOR]

There will be common challenges to scaling‐up any ionic liquids separations technologies which require very large volumes of ionic liquid. Some of these challenges are illustrated in this personal account which chronicles the extraction of chitin from shrimp shell from discovery to current commercialization efforts. The road being taken from discovery in an academic laboratory, through attempts to navigate the scaling‐up to commercial scale using the vehicle of a faculty startup company is rewarding, but fraught with roadblocks, detours, and unexpected challenges. The differences in 'technically feasible' and 'commercially viable' are not always evident from the beginning of the journey, however, one wonders what achievements we miss as a Society because it was assumed to not be commercially viable. [ABSTRACT FROM AUTHOR]

In order to effectively harness varieties of mechanical waves or vibrations for the purpose of monitoring and/or powering, developments in responsive materials and conversion technologies are taking place driven by the world's current and future demands. One of the most popular novelties of the last two decades is represented by hydrogel‐ or ionogel‐based flexible iontronics which constitute a wide family of innovative smart (self‐powered) mechanoreceptors relevant for various applications such as personal health care, identity and safety monitoring, intelligent human‐machine operation interfaces, underwater listening and communication, and so on. Cellulosic gels (CGs), as a promising green substitute for fossil fuel‐derived materials, are extensively studied due to the possibility to choose between different cellulose types and to formulate networks chemically or physically, according to the adaptability requirements for each target application. The aim of this review is to showcase the cellulose structural versatility and to provide a summary of the principles during the formulation of CGs used for mechanosensing and mechanical energy scavenging, as well as their practical applications. Such an outlook of current challenges and overall prospects will serve as a stimulus for research on CG‐based mechanoreceptors in the future. [ABSTRACT FROM AUTHOR]

In search of ionic liquids (ILs) with multiple types of soft donor atoms capable of preferentially complexing a range of soft metal ions over harder ions, we investigated structural clues to the role of hydrogen bonding in IL behavior through a series of salts with anions containing both N- and S-donor atoms based on azole thiolates. Reaction of equimolar amounts of triethylamine (Et3N) or diisobutylamine (DBA) with 1-phenyl-1H-tetrazole-5-thiol (PhTzSH), 1-methyl-1H-tetrazole-5-thiol (MeTzSH), or 5-methyl-1,3,4-dithiazole-2-thiol (MeDiTSH) yielded [Et3NH][MeTzS] (1), a yellow liquid, and the low melting yellow solids [DBAH][MeTzS] (2), [Et3NH][PhTzS] (3), [DBAH][PhTzS] (4), [Et3NH][MeDiTS] (5), and [DBAH][MeDiTS] (6). Thermal analysis revealed that all of them qualify as ILs with melting points below 100 °C. Single crystal X-ray structure analysis of 2–6 revealed the presence of an extensive H-bonding network that includes the rare N–H⋯S hydrogen bonds in 3, 4, and 6. These weaker interactions appear to significantly influence thermal behavior, where strong bonding leads to higher melting temperatures and lower decomposition points. [ABSTRACT FROM AUTHOR]

This work provides a comprehensive evaluation of the effect of the cation alkyl side chain length of the 1-alkyl-3-methylimidazolium chloride series ([CnC1im]Cl, n = 2-14) of ionic liquids (ILs) on their capability to form aqueous biphasic systems (ABSs) with salts and self-aggregation derived properties. The liquid-liquid phase behavior of ternary systems composed of [CnC1im]Cl, water, and K3PO4 or K2CO3 and the respective Setschenow salting-out coefficients (ks), a quantitative measure of the two-phase formation ability, were determined. An odd-even effect in the ks values along the number of methylene groups of the longest IL cation alkyl side chain was identified for the ABS formed by K2CO3, a weaker salting-out agent where the phenomenon is clearly identified. In general, cations with even alkyl side chains, being likely to display higher molar volumes, are more easily salted-out and thus more prone to undergo phase separation. The odd-even effect in the ks values is, however, more significant in ILs up to n = 6, where the nanostructuration/nanosegregation of ILs plays a less relevant role. Still, with the [CnC1im]Cl (n = 7-14) series of ILs, an odd-even effect was also identified in the ILs’ ionization degree, molar conductivity, and conductivity at infinite dilution. In summary, it is shown here that the ILs’ odd-even effect occurs in IL aqueous solutions and not just in neat ILs, an already well-established phenomenon occurring in a series of ILs’ properties described as a result of the orientation of the terminal methyl groups to the imidazolium ring cation and consequent effect in the ILs’ cohesive energy. [ABSTRACT FROM AUTHOR]

Aqueous solutions of a series of short carbon chain tetra(n-alkyl)ammonium hydroxides, [Nnnnn][OH] with n = 2: n-ethyl, 3: n-propyl, 4: n-butyl, have been serendipitously found to be potential candidates for direct air carbon capture (DAC) when being used as reagents in more complicated reactions. Aqueous solutions of [N3333][OH], [N2222][OH], or [N3333][OH] with UO2SO4·3H2O and 1,4-diamidoximylbenzene, and [N4444][OH] with cytosine (HCyt) directly absorb CO2 from the atmosphere upon mild heating in the open atmosphere crystallizing in complexes reaching up to 2 : 1 CO2/[Nnnnn]OH ratio. [N2222][HCO3]·3H2O (1), [N2222]2[H(HCO3)3]·5H2O (2), [N3333][HCO3]·0.5H2O (3), [N3333][H(HCO3)2] (4), [N3333]2[(tpa)(H2CO3)2] (5; tpa = terephthalate), [N4444][H(Cyt)(HCO3)]·H2O (6) and [N4444][H2(Cyt)2(HCO3)]·H2O (7) have been isolated in crystalline form and structurally characterized by single crystal X-ray diffraction. The compounds are characterized by complex polyanionic formations from bicarbonate dimers ([(HCO3)2·(H2O)]24−) or chains ([H(HCO3)2]nn− or [H2(tpa)(HCO3)2]n2n−) to water-bicarbonate associates ([(HCO3)2·6H2O]2− and [(H2CO3·(HCO3)2)2·6H2O·2H2O]2−) and three-component anionic layers ([H(Cyt)(HCO3)·H2O]nn− and [H2(Cyt)2(HCO3)·H2O]nn−) frequently showing proton sharing. While some hydroxides themselves can maintain a high CO2/[Nnnnn][OH] ratio, particularly 2 and 4, the presence of secondary hydrogen bond donors/acceptors may increase the sorption efficiency through decreased solubility and enhanced crystallization. [ABSTRACT FROM AUTHOR]

The use of salts as energetic materials in the field of energetic ionic liquids (ILs) is discussed.

The high-resolution single-crystal X-ray structure for the coordination of the 1-methylimidazole (Meimid) ligand to U[O.sub.2][Ac.sub.2] (Ac=C[H.sub.3]C[O.sub.2]) is presented. Findings confirm the direct participation of the nitrogen atom of the Meimid ligand in binding to the uranium center.

An approach is described to predict the thermodynamics for forming a variety of salts, intrinsically nonvolatile and thermally stable under normal conditions, and ionic liquids from typical starting materials. Electronic structure calculations were performed using the Gaussian03(sub 21) suite of program.

Solvent extraction of cesium ions from aqueous solution to hydrophobic ionic liquids without the introduction of an organophilic anion in the aqueous phase was demonstrated using calix[4]arene-bis(tert-octylbenzo-crown-6) (BOBCalixC6) as an extractant. The selectivity of this extraction process toward cesium ions and the use of a sacrificial cation exchanger (NaB[Ph.sub.4]) to control loss of imidazolium cation to the aqueous solutions by ion exchange have been investigated.