Oakland University

Covalent Associates, Inc.

Rex Xiaofeng Ren

Xiangqun Zeng

Lei Yu

Victor R Koch

An ionic liquid piezoelectric gas sensor for the detection of polar and nonpolar organic vapors. The gas sensor can operate at high temperatures with a fast linear response which is also reversible. At high temperatures, the frequency change (&#x394;f) versus concentration (C) curve mirrors the Henry's gas law, such that the concentration of a gas sample in liquid solvent is proportional to the concentration or partial pressure of the sample in gas phase. The gas sensor can be used for quantitative analysis of gas vapors and determination of Henry constants.

Ionic liquid high temperature gas sensors

 This invention describes a one pot, single-step process for the preparation of halide-free hydrophobic salts comprising polyalkylated imidazolium cations and various anions in accordance with the following structure, where Rand Rrepresent the either the same or different alkyl groups, and R, R, and Rrepresent either hydrogen atoms, or the same or different alkyl group substituents; X represents a polyatomic anion that is the conjugate base of an acid. By simply mixing aqueous formaldehyde with an alkyl amine such as methylanune, ethylamine, n-propyl oriso-propylamine, or n-butyl-, iso-butyl, or t-butylamine, or by mixing aqueous formaldehyde with two alkyl amines (preferably one being methylamine, ethylamine, n-propyl- or iso-propylamine, or n-butyl-, isobutyl, or t-butylamine) and another being n-propyl- or isopropylaine, or n-butyl-, isbutyl, or t-butylamine), an acid (such as hexafluorophosphoric acid, trifluoroacetic acid, pentafluoropropionic, heptafluorobutyric acid, or the free acid of a bis(perfluoroalkylsulfonyprnide or tris(perfluoroalkylsulfonyl)methide as the source of the anion) and aqueous glyoxal solution, the hydrophobic ionic salts or mixtures thereof thus formed may be conveniently separated directly from the aqueous byproduct layer. Like the single cation hydrophobic salts, these mixed hydrophobic ionic liquids are non-flammable and manifest no detectable vapor pressure up to their decomposition temperature of greater than 300&#xb0; C. We have also discovered that, surprisingly, ternary mixtures of dialkylated ionic liquids manifest higher ionic conductivities than a single ionic liquid of the mixture alone. This property benefits electrochemical power source applications such as batteries and capacitors. Furthermore, we have discovered that ternary mixtures of dialkylated ionic liquids absorb microwave radiation more efficiently than a single ionic liquid of the mixture alone. This property benefits microwave-induced synthetic reactions. Such physical and chemical properties make it possible to employ inexpensive mixtures of polyalkylated imidazolium cations in an advantageous manner as thermal transfer fluids, high temperature lubricants, and plasticizers, and as solvents in the areas of electrochemistry, synthetic chemistry, catalysis, and separations chemistry.

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Middletown, CT, United States of America

Rex Xiaofeng Ren