Zinc Silicates: Very Efficient Heterogeneous Catalysts for the Addition of Primary Alcohols to Alkynes and Allenes.

There is an astonishing parallel between the mechanism generally accepted for the addition of water to CO2 catalyzed by the enzyme carbonic anhydrase and the mechanism calculated for the addition of methanol to allene catalyzed by the naturally occurring zinc silicate hemimorphite. The latter reaction was investigated in detail following the observation that hemimorphite as well as an amorphous zinc silicate prepared in situ are excellent heterogeneous catalysts for the addition of primary alcohols to alkynes and allenes [Eq. (1)].

Determination of primary, secondary, and tertiary amines in air by direct or diffusion sampling followed by determination with liquid chromatography and tandem mass spectrometry.

Two different methods for sampling of primary, secondary, and tertiary aliphatic and aromatic amines in air have been developed for improving amine analysis in air. The aim was to have a quick method for direct sampling of amines at defined times, for example, for material testing as well as for long-term measurements of amines by diffusive sampling during field studies without sampling instrumentation. The goal of the study was chemical analysis of amines, especially focusing on an analytical method suitable for tertiary amines besides primary and secondary amines. For both direct and diffusive sampling, samplers working with phosphoric acid impregnated glass wool for trapping of amines by formation of quaternary ammonium salts have been designed and tested. Direct sampling was applied for in-car emission measurement and for polyurethane exhalation monitoring by drawing air from 1 m3 test chambers through amine sampling devices. Diffusive sampling was applied for the same in-car measurement and for field measurement at a landfill leachate uptake with an obnoxious smell. Quantification of sampled analytes was achieved by LCMS/MS analysis.

Toxicity of parked motor vehicle indoor air.

The interior of motor vehicles is made of a wide variety of synthetic materials, which emit volatile organic compounds (VOC). We tested the health effects of emissions from vehicles exposed to "parked in sunshine" conditions. A new and a 3 year old vehicle with identical interior were exposed to 14 000 W of light. Indoor air was analyzed by GC-MS. Toxicity of extracts of indoor air was assayed in human primary keratinocytes, human lung epithelial A549 cell line, and Chinese hamster V79 lung fibroblasts. In addition, toxicity after metabolic activation by CYP1A1, CYP1A2, CYP1B1, CYP2A6, CYP2B6, and CYP2E1 was assayed. The effect on type I allergic reaction (IgE-mediated immune response), type IV allergic reaction (T-cell mediated immune response), and irritative potential was evaluated also. A total of 10.9 and 1.2 mg/m(3) VOC were found in new and used motor vehicle indoor air, respectively. The major compounds in the new vehicle were o,m,p-xylenes, C3 and C4-alkylbenzenes, dodecane, tridecane, and methylpyrrolidinone. In the used vehicle they were acetone, methylpyrrolidinone, methylcyclohexane, acetaldehyde, o,m,p-xylenes, ethylhexanol, and toluene. No toxicity was observed in any cell line with or without metabolic activation. Neither did we find an effect on type IV sensitization or an irritative potential. A slight but statistically significant aggravating effect on IgE-mediated immune response of only the new vehicle indoor air was determined (p < 0.05). The IgE-response modulating effect of indoor air might be relevant for atopic individuals. Else no direct toxicity, no toxicity after metabolic activation by cytochrome P450, and no irritative or type IV sensitizing potential of motor vehicle indoor air were found, neither from the new nor used vehicle. Our investigations indicated no apparent health hazard of parked motor vehicle indoor air.