Deep Eutectic Solvents: Alternative Solvents for Biomass-Based Waste Valorization.

Innovative technologies can transform what are now considered "waste streams" into feedstocks for a range of products. Indeed, the use of biomass as a source of biopolymers and chemicals currently has a consolidated economic dimension, with well-developed and regulated markets, in which the evaluation of the manufacturing processes relies on specific criteria such as purity and yield, and respects defined regulatory parameters for the process safety. In this context, ionic liquids and deep eutectic solvents have been proposed as environmentally friendly solvents for applications related to biomass waste valorization. This mini-review draws attention to some recent advancements in the use of a series of new-solvent technologies, with an emphasis on deep eutectic solvents (DESs) as key players in the development of new processes for biomass waste valorization. This work aims to highlight the role and importance of DESs in the following three strategic areas: chitin recovery from biomass and isolation of valuable chemicals and biofuels from biomass waste streams.

Hypergolic Triggers as Co-crystal Formers: Co-crystallization for Creating New Hypergolic Materials with Tunable Energy Content.

We demonstrate a co-crystal-based strategy to create new solid hypergols, that is, materials exhibiting spontaneous ignition when in contact with an oxidant, from typically non-hypergolic fuel molecules. In these materials, the energy content and density can be changed without affecting the ignition delay. The use of an imidazole-substituted decaborane as a hypergolic "trigger" component in combination with energy-rich but non-hypergolic nitrobenzene or pyrazine yielded hypergolic co-crystals that combine improved combustion properties with ultrashort ignition delays as low as 1 ms.

New Reactions for Old Ions: Cage Rearrangements, Hydrolysis, and Two-Electron Reduction of nido-Decaborane in Neat 1-Ethyl-3-Methylimidazolium Acetate.

The access to free, unsolvated ions at high concentrations and ambient temperatures enabled by ionic liquids results in previously unobserved reactivity for even well-studied ions, demonstrated here by acetate ([OAc]-) acting as a reducing agent for B10H14 but only when used as a neat liquid in [C2mim][OAc] at ambient temperature. More typical reaction products are obtained when B10H14 is reacted with [C2mim][OAc] at an elevated temperature or in the presence of strong bases.

Versatility and remarkable hypergolicity of exo-6, exo-9 imidazole-substituted nido-decaborane.

The combination of an energetic imidazole bonded to a hypergolic trigger, such as certain boron hydride clusters, dramatically improves both the energy density and ignition delay of the resulting compounds while also introducing tunability via alkyl group substitution as demonstrated here with (Rim)2B10H12 (R = H, C1, C2, and C4).