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1. Solvent effects on catalytic activity and selectivity in amine-catalyzed d-fructose isomerization

   https://doi.org/10.1016/j.jcat.2022.12.029  

   Drabo, Peter; Fischer, Matthias; Emondts, Meike; Hamm, Jegor; Engelke, Mats; Simonis, Marc; Qi, Long; Scott, Susannah L.; Palkovits, Regina; Delidovich, Irina (February 2023, Journal of Catalysis)

   Rational catalyst design and optimal solvent selection are key to advancing biorefining. Here, we explored the organocatalytic isomerization of d-fructose to a valuable rare monosaccharide, d-allulose, as a function of solvent. The isomerization of d-fructose to d-allulose competes with its isomerization to d-glucose and sugar degradation. In both water and DMF, the catalytic activity of amines towards d-fructose is correlated with their basicity. Solvents impact the selectivity significantly by altering the tautomeric distribution of d-fructose. Our results suggest that the furanose tautomer of d-fructose is isomerized to d-allulose, and the fractional abundance of this tautomer increases as follows: water < MeOH < DMF ≈ DMSO. Reaction rates are also higher in aprotic than in protic solvents. The best d-allulose yield, 14 %, was obtained in DMF with 1,5,7-triazabicyclo[4.4.0]dec-5-ene (TBD) as the catalyst. The reaction kinetics and mechanism were explored using operando NMR spectroscopy. 

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2. Reduction reactions at metal/non-aqueous interfaces can be sensed with the turn-on fluorophore resazurin

   https://doi.org/10.1039/D2QM01309F  

   Gatland, Zachary; Madrid, Daniel; Siegel, Mark; Kisley, Lydia (March 2023, Materials Chemistry Frontiers)

   Interfacial oxidation–reduction reactions have important applications in corrosion and catalysis, but traditional electrochemical cell methods cannot be used to study these reactions in non-conducting environments such as non-aqueous solvents. We demonstrate that the molecule resazurin that can be reduced to highly-fluorescent resorufin is compatible for sensing in non-aqueous solvents. We characterize the spectral properties of the dyes in ethanol, dimethylformamide (DMF), acetone, and dimethyl sulfoxide (DMSO), showing a ∼10× increase in intensity for “turned-on” resorufin compared to resazurin in all four solvents. We then apply resazurin to sense corrosive reduction reactions at iron surfaces. Increases in fluorescence intensity due to resazurin reduction to resorufin are observed in ethanol, acetone, and DMSO, while DMF had no turn-on. Our work shows that fluorescent dyes have considerable potential to be used to understand redox reactions in non-aqueous solvents, but care must be taken to understand the interplay between the dye, the solvent, and the reactions occurring. 

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3. Novel perfluorinated nanofiltration membranes for isolation of pharmaceutical compounds

   https://doi.org/10.1016/j.seppur.2020.117944  

   Chau, John; Sirkar, Kamalesh K; Pennisi, Kenneth J; Vaseghi, Gazelle; Derdour, Lotfi; Cohen, Benjamin (January 2021, Separation and purification technology)

   null (Ed.)

   Polymeric membranes for separation of pharmaceutical intermediates/products by organic solvent nanofiltration (OSN) have to be highly resistant to many organic solvents including high-boiling polar aprotic ones, e.g., N- methyl-2-pyrollidone (NMP), dimethylsulfoxide (DMSO), dimethylformamide (DMF). Unless cross-linked, few polymers resist swelling or dissolution in such solvents; however particular perfluoropolymers are resistant to almost all solvents except perfluorosolvents. One such polymer, designated AHP1, a glassy amorphous hydrophobic perfluorinated polymer, has been studied here. Additional perfluoropolymers studied here are hydrophilically modified (HMP2 and HMP3) versions to enhance the flux of polar aprotic solvents. OSN performances of three types of membranes including the hydrophilically modified ones were studied via solvent flux and solute rejection at pressures up to 5000 kPa. The solutes were four active pharmaceutical ingredients (APIs) or pharmaceutical intermediates having molecular weights (MWs) between 432 and 809 Da and three dyes, Oil Blue N (378 Da), Sudan Black B (456 Da), Brilliant Blue R (826 Da). Solvents used were: ethyl acetate, toluene, n- heptane, iso-octane, DMSO, tetrahydrofuran (THF), DMF, acetone, NMP, methanol. Test cells included stirred cells and tangential flow cells. Pure solvent fluxes through three membrane types were characterized using a particular parameter employing various solvent properties. All three membranes achieved high solute rejections around 91–98% at ambient temperatures. HMP2 membrane achieved 95% solute rejection for an API (809 Da) in DMSO at a high temperature, 75 ◦C. A two-stage simulated nanofiltration process achieved 99%+ rejection of a pharmaceutical intermediate (MW, 432 Da) in 75v% NMP-25v% ethyl acetate solution. 

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4. Improved Performance of Silicon-Containing Anodes with Organic Solvent-Solubilized Lithium Nitrate

   https://doi.org/10.1149/1945-7111/acdd26  

   Rynearson, Leah; Jayawardana, Chamithri; Yeddala, Munaiah; Lucht, Brett L. (June 2023, Journal of The Electrochemical Society)

   Three different organic solvents (dimethylacetamide (DMAc), dimethylformamide (DMF), and dimethyl sulfoxide (DMSO)) were used to improve the solubility of LiNO 3 in a standard carbonate-based electrolyte with lithium difluoro(oxalato)borate (LiDFOB) as the salt. Together, the LiDFOB and organic-solvent solubilized LiNO 3 preferentially reduce on the surface of silicon-containing anodes to create an SEI rich in oxalates, nitrate decomposition species, and B-F species. The improved stability of the SEI throughout the first 100 cycles results in silicon and silicon/graphite composite anodes with better capacity retention than observed with standard electrolytes or fluoroethylene carbonate (FEC) containing electrolytes. This study demonstrates the feasibility of the use of non-traditional electrolyte solvents in the improvement and optimization of lithium ion-battery electrolytes. 

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5. Eco‐Friendly Solvent Engineered CsPbI _2.77 Br _0.23 Ink for Large‐Area and Scalable High Performance Perovskite Solar Cells

   https://doi.org/10.1002/adma.202310279  

   Abate, Seid_Yimer; Qi, Yifang; Zhang, Qiqi; Jha, Surabhi; Zhang, Haixin; Ma, Guorong; Gu, Xiaodan; Wang, Kun; Patton, Derek; Dai, Qilin (December 2023, Advanced Materials)

   Abstract The performance of large‐area perovskite solar cells (PSCs) has been assessed for typical compositions, such as methylammonium lead iodide (MAPbI₃), using a blade coater, slot‐die coater, solution shearing, ink‐jet printing, and thermal evaporation. However, the fabrication of large‐area all‐inorganic perovskite films is not well developed. This study develops, for the first time, an eco‐friendly solvent engineered all‐inorganic perovskite ink of dimethyl sulfoxide (DMSO) as a main solvent with the addition of acetonitrile (ACN), 2‐methoxyethanol (2‐ME), or a mixture of ACN and 2‐ME to fabricate large‐area CsPbI_2.77Br_0.23films with slot‐die coater at low temperatures (40–50 °C). The perovskite phase, morphology, defect density, and optoelectrical properties of prepared with different solvent ratios are thoroughly examined and they are correlated with their respective colloidal size distribution and solar cell performance. The optimized slot‐die‐coated CsPbI_2.77Br_0.23perovskite film, which is prepared from the eco‐friendly binary solvents dimethyl sulfoxide:acetonitrile (0.8:0.2 v/v), demonstrates an impressive power conversion efficiency (PCE) of 19.05%. Moreover, the device maintains ≈91% of its original PCE after 1 month at 20% relative humidity in the dark. It is believed that this study will accelerate the reliable manufacturing of perovskite devices. 

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