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A protic ionic liquid (PIL) composed of 1,8-diazabicyclo[5.4.0]-undec-7-ene (DBU) and acetic acid can dissolve cellulose under mild conditions and catalyse its transesterification. To investigate the relationship between physicochemical properties and chemical structures, PILs composed of DBU and carboxylic acids with varying alkyl chain lengths were prepared as cellulose-dissolving solvents. The thermal behaviours of the PILs were analysed by thermogravimetry and differential scanning calorimetry, and their viscosities, ionic conductivities, and cellulose-dissolution abilities were determined. The effect of the alkyl chain length in the carboxylate ion on the physicochemical properties of the PILs was investigated. With increasing chain length, the thermal stability and ionic conductivity increased, whereas the melting point (T m), glass-transition temperature (T g), cellulose solubility, and viscosity decreased. The cellulose solubility increased as the difference between the p K a values of the DBU and carboxylic acid (Δp K a) increased. In addition, the cellulose solubility increased with the increasing density of the PIL. It was revealed that PILs with a high Δp K a value and a carboxylate ion with a short alkyl chain are suitable for cellulose dissolution. A protic ionic liquid (PIL) composed of 1,8-diazabicyclo[5.4.0]-undec-7-ene (DBU) and acetic acid can dissolve cellulose under mild conditions and catalyse its transesterification. In this study, PILs composed of DBU and carboxylic acids with varying alkyl chain lengths were prepared, and the relationship between physicochemical properties and chemical structures was investigated. [ABSTRACT FROM AUTHOR]

Cellulose acetate (CA) is a resin derived from biomass. In addition to its various superior properties, CA is preferable to existing petroleum-derived resins from the viewpoint of green chemistry. Therefore, the acetylation of cellulose is one of the most important subjects in cellulose research. In this study, we found that the acetylation of cellulose could proceed in some protic ionic liquids (PILs) composed of amidine and acetic acid with ΔpKa = ca. 8.4–8.7 under mild conditions without any catalyst. The degree of substitution (DS) of the produced CA was above 1.84, and the maximum DS was 2.87 when the ΔpKa of the PIL was about 8.5. In propionate-based PILs, cellulose was not only acetylated but also propionated; however, the cellulose acetylation did not occur in formate-based PILs. It was revealed that the esterification of cellulose proceeded through the anion exchange between carboxylic anhydride and anion species of the PIL. [ABSTRACT FROM AUTHOR]

Lipase-catalyzed polymerizations of L-lactide were carried out in four kinds of ionic liquids (ILs) in order to investigate the effect of ILs on the conversion, molecular weight, and yield of the obtained poly(lactide) (PLLA). PLLA could be synthesized in ILs of 1-butyl-3-methylimidazolium ([C4mim]) except in [C4mim][N(CN)2]. While the number-average molecular weight ( Mn) of the PLLA obtained in [C4mim][PF6] was below 4000 g mol−1 and the yield was below 10%, the Mn and yield of the PLLA obtained in [C4mim][BF4] reached 55000 g mol−1 and 35%, respectively. The Mn values of PLLAs in the ILs were clearly higher than those of PLLAs obtained in bulk and in toluene (<44000 g mol−1). The polymerization in the ILs proceeds even at lower temperatures as compared with that in bulk. The effect of lipase content on the Mn of PLLA was also investigated. When [C4mim][BF4] was used as the solvent, the highest Mn was obtained at a lipase content of 10 wt%. In the case of [C4mim][NTf2], the most suitable lipase content depended on the polymerization temperature. [C4mim][BF4] was suitable to obtain higher molecular weight PLLA and higher polymer yield at lower lipase contents. Copyright © 2008 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Ionic liquids (ILs) containing zwitterions have been studied as electrolytes for lithium-ion batteries (LIBs). The effects of addition of a pyrrolidinium zwitterion in an IL electrolyte on the thermal and electrochemical stability and charge/discharge properties of Li/LiCoO 2 and graphite/Li cells were investigated. The thermal decomposition temperature of the IL electrolyte composed of N -methyl- N -propylpyrrolidinium bis(fluorosulfonyl)amide ([P13][FSA])/lithium bis(trifluoromethylsulfonyl)amide (LiTFSA) with 3-(1-butylpyrrolidinium)propane-1-sulfonate (Bpyps) as the zwitterionic additive, the thermal decomposition temperature was about 300 °C. The electrochemical window of [P13][FSA]/LiTFSA/Bpyps was 0–+5.4 V vs. Li/Li + , which was almost identical to that of [P13][FSA]/LiTFSA. Li|electrolyte|LiCoO 2 cells containing the IL/Bpyps electrolyte system exhibited high capacities in the cut-off voltage range of 3.0–4.6 V, even after 50 cycles. The increase in the interfacial resistance between the electrolyte and cathode with cycling was suppressed. In the cyclic voltammograms of cells employing a graphite electrode, the intercalation/deintercalation of lithium ions were observed in the range of 0 and + 0.4 V vs. Li/Li + . Further, graphite|electrolyte|Li cells containing [P13][FSA]/LiTFSA/Bpyps exhibited stable charge/discharge cycle behaviour over 50 cycles. [ABSTRACT FROM AUTHOR]

Ionic liquids (ILs) containing zwitterions were studied as electrolytes for lithium-ion batteries. The effect of a pyrrolidinium zwitterion with a long ether side chain on the thermal and electrochemical properties of an IL and the charge/discharge properties of Li/LiCoO 2 , Li/LiNi 1/3 Mn 1/3 Co 1/3 O 2 (NMC), and graphite/Li cells with IL/zwitterion electrolytes was investigated. The melting temperature of the IL-based electrolyte composed of N -methyl- N -methoxymethylpyrrolidinium bis(fluorosulfonyl)amide ([Pyr 1,1O1 ][FSA]) and lithium bis(fluorosulfonyl)amide (LiFSA) with 3-(1-(2-(2-methoxyethoxy)ethyl)pyrrolidin-1-ium-1-yl)propane-1-sulfonate (OE2pyps) as the zwitterionic additive was about −18 °C. The electrochemical window of [Pyr 1,1O1 ][FSA]/LiFSA/OE2pyps was over 5 V vs. Li/Li + . Li|electrolyte|LiCoO 2 cells containing the [Pyr 1,1O1 ][FSA]/LiFSA/OE2pyps electrolyte system exhibited high capacity values in the cut-off voltage range of 3.0–4.3 V, even after 50 cycles. Moreover, increases of interfacial resistance between the electrolyte and cathode during cycling were suppressed. Li|electrolyte|NMC cells containing this electrolyte system also exhibited high capacities in a wide cut-off voltage range of 3.0–4.6 V, even after 50 cycles. In the cyclic voltammograms of cells employing a graphite electrode, the intercalation/deintercalation of lithium ions was observed between 0 and + 0.4 V vs. Li/Li + . Further, graphite|electrolyte|Li cells containing [Pyr 1,1O1 ][FSA]/LiFSA/OE2pyps exhibited stable charge/discharge cycle behavior over 5 cycles. [ABSTRACT FROM AUTHOR]