Lipase activity and stability was investigated in dialkylimidazolium and pyrrolidinium-based ionic liquids with a variety of anions including hexafluorophosphate, acetate, nitrate, methanesulfonate, trifluoroacetate, and trifluoromethylsulfonate. The initial rate of lipase-catalyzed transesterification of methyl methacrylate in these ionic liquids and several organic solvents was examined as well as the polytransesterification of divinyl adipate and 1,4-butanediol. Free lipase (Candida rugosa) catalyzed the transesterification of methyl methacrylate in 1-butyl-3-methylimidazolium hexafluorophosphate at a rate 1.5 times greater than in hexane. However, no detectable activity was observed in all the "hydrophilic" ionic liquids studied. Methods of enzyme stabilization including adsorption, PEG-modification, and immobilization in polyurethane foam were ineffective in improving enzymatic activity in the hydrophilic ionic liquids. Polytransesterifications performed in 1-butyl-3-methylimidazolium hexafluorophosphate using Novozym 435 produced polyesters with weight average molecular weights limited to 2900 Da due to precipitation of the polymer. Solvatochromic studies and partition coefficient measurements suggest that ionic liquids are more polar and hydrophilic than organic solvents such as hexane, acetonitrile, and tetrahydrofuran. Stability studies indicate that lipases exhibit greater stability in ionic liquids than in organic solvents including hexane.

Room-temperature ionic liquids (ILs) have been proposed as alternative solvents for organic synthesis, separations, and electrochemical applications. Here, we report studies that probe the electrochemical and solvation properties of a tetraalkylammonium (methyltributylammonium bis(trifluoromethylsulfon)imide, M3BNIm) and an imidazolium (1-butyl-3-methylimidazolium hexafluorophosphate, BMIPF6) based ionic liquid. It is demonstrated that despite impurities, the cathodic limit at a Pt electrode is enhanced for the tetraalkylammonium-based IL. Electrogenerated chemiluminescence of tris(2,2‘-bipyrindinyl)ruthenium (Ru(bpy)3 2+) was observed in both ionic liquids, and differences in the response were interpreted in terms of the solvent reactivity and polarity. As ILs have been proposed as alternatives to organic solvents in extraction processes, an understanding of the relative lipophilicity of the IL ions and the equilibrium potential difference established across the IL/water interface is of fundamental relevance. Here, electrochemical measurements at a conventionally polarized liquid−liquid interface (water/1,2-dichloroethane) were used to determine the relative lipophilicity of the IL constituent ions. From formal ion transfer potential values (   ) obtained, the standard ionic partition coefficients could be estimated. The polarizability of the neat ionic liquid/water interface was investigated. From these studies, it can be seen that BMIPF6 is hydrophilic while M3BNIm is moderately hydrophobic. The significance of the potential difference established across the IL/water interface is discussed.

The aluminosilicate molecular sieve with the AEI framework topology (SSZ-39) is currently of great interest for use in a number of important applications such as exhaust gas NO x reduction and the methanol-to-olefins reaction. It is likely that advances in the synthesis of this molecular sieve will be needed for applications to proceed. Here, dimethylpiperidine based organic structure directing agents (OSDAs) are used to prepare SSZ-39, and the influence of diastereo-and structural isomeric mixtures on the synthesis of SSZ-39 is reported. Although differences in the rates of molecular sieve formation as well as preferential isomer incorporation occur, the synthesis of SSZ-39 is possible over a wide range of isomeric mixtures. These findings demonstrate that the synthesis of SSZ-39 can be accomplished with OSDA isomer mixtures that naturally occur from the synthesis of the organic precursors used to prepare the OSDAs.

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Quaternary ammonium salts have been studied as ionic liquids for electrochemical applications, including sodium batteries. Mixtures of benzyltrialkylammonium chlorides with chloroaluminate formed ionic liquids near room temperature. The maximum coulombic efficiency for the reduction and re-oxidation of sodium ions with benzyltriethylammonium chloride ionic liquid was over 91%. The self-discharge current for a sodium electrode in this ionic liquid was 32.7 and 18 A/cm 2 by chronopotentiometry at tungsten electrodes at 6.37 and 2.55 mA/cm 2 , respectively. These are comparable to values in 1-methyl-3-propylimidazolium chloride melt. Issues with the coulombic efficiencies and the self-discharge currents are discussed.

A thorough study of SSZ-39 formation, a next generation deNOx catalyst, is presented. The presence of the trans isomer is beneficial to the growth kinetics leading to enhancements in the growth rate, in some cases of over 40%. The formation of SSZ-39 is also sensitive to the composition of the faujasite used as an aluminum source as gels with identical compositions but different faujasites do not lead to SSZ-39 formation. Once SSZ-39 begins to form, its growth rate is linear and appears to equal the rate of faujasite dissolution. Finally, the Si/Al ratio of the material is influenced by the cis/trans ratio of the SDA. These results provide new insights into the formation of this industrially relevant catalyst.

The preparation, and conductivity, calorimetric, and electrochemical studies of MEEP/PPO-(LiX)~ mixed polymer electrolytes, where MEEP = poly[bis-(methoxyethoxyethoxide)phosphazene], PPO = poly(propylene oxide) and LiX = LiBF4, LiCIO4, LiCF3SO3, LiAsF6, and LiAICI4, are described. The addition of PPO in various proportions to MEEP-(LiX)~ electrolytes significantly improved the latter's dimensional stability but caused a slight decrease in its conductivity. The conductivities of these mixed polymer electrolytes" are much higher than that of PPO-(LiX)n. The Li + transport number in MEEP/PPO-(LiX)0.13 electrolytes, with LiX = LiBF4 and LiCIO4, was determined to be between 0.3 and 0.5. Differential scanning calorimetric data established the predominantly amorphous nature of the mixed polymer complexes. Cyclic voltammetric studies of these electrolytes at a stainless steel electrode indicated a stability domain between 1 and 4.5V (vs. Li+/Li), and established the good Li plating and stripping efficiency in these electrolytes.