Malodorants characteristics

Elevated Flares See Flares for a general definition. The elevated flare, by the use of steam injection and effective tip design, operates as a smokeless combustion device. Flaring generally is of low luminosity up to about 20 % of maximum flaring load. Steam injection tends to introduce a source of noise to the operation, and a compromise between smoke elimination and noise is usually necessary. When adequately elevated (by means of a stack) this type of flare displays the best dispersion characteristics for malodorous and toxic combustion products. Visual and noise pollution often creates nuisance problems. Capital and operating costs tend to be high, and an appreciable plant area can be rendered unavailable for plant operations and equipment because of excessive radiant heat. 

Malodorants have strong, repulsive characteristics including nausea, gagging, and/or vomiting. Unpleasant odors impede cognitive performance, increase feelings of discomfort,... 

Dimethyl(pentafluorophenyl)arsine is a colorless, malodorous liquid which has a nmr spectrum in dichloromethane consisting of a triplet centered at t8.51 with /PH = 1.1 Hz. A methyl iodide derivative of the arsine can be prepared by refluxing 1.7 g of the arsine with 15 ml of methyl iodide for 2 hr. After evaporation of the solvent and recrystallization of the product from a dichloromethane-benzene mixture, a colorless compound which melts at 167-168° is obtained. The nmr spectrum of the methyl iodide derivative is a triplet at t7.16 (Jfh = 1.4 Hz) in dichloromethane, and the infrared spectrum (Nujol mull) contains strong peaks at 1080 and 980 cm characteristic of the CeFs group. Anal, (done on the methyl iodide derivative). Calcd. for C9H9-FsAsI C, 26.09 H, 2.17 1, 30.68. Found C, 25.5 H, 2.21 I, 30.1. 

In general, the simple phospholes are malodorous, colorless materials that require great care in handling because of their ease of oxidation. Those with more complex structures, especially where conjugating substituents are present, are less volatile and oxidizable, and can be relatively inoffensive. These characteristics figure prominently in the design of experiments to determine physical and other properties of phospholes. 

Kim K-H, Choi B-J, Yun S-T, Hwang S-J (2004) Studies of spatial and temporal distribution characteristics of TSP-bound trace metals in Seoul, Korea. Environ Pollut 127(3) 323-333 Kim K-H, Jeon E-C, Choi Y-J, Koo YS (2006) The emission characteristics and the related malodor intensities of gaseous reduced sulfur compounds (RSC) in a large industrial complex. Atmos Environ 40(24) 4478 1490... 

SBSE has some operational drawbacks in taking the stir bar from the sample, rinsing, and drying the stir bar, which are usually performed manually. SBSE delds theoretical recoveries under 90% for analytes with log ICo/w < 2, which implies a limitation of the technique. Both SBSE and SPME are compared in the analysis of malodors wastewater due to characteristic polar compoimds from animal-rearing facilities. However, PA fibers are best suited for the analysis of polar compoimds. SBSE achieved more reproducible results than SPME for aromatic polar compoimds [184]. 

Several alkyl-branched fatty acids were found to be powerful and characteristic food flavors. 2-Methylbutyric acid is an important constituent of the aroma of cranberry Vaccinium vitis-idaea L.) (77). 3-Methyl-valeric acid and isovaleric acid were identified in tobacco leaves and found to contribute to the distinct sensory properties of Turkish tobacco smoke 590). Isovaleric acid, which has the lowest flavor threshold (0.7 ppm) 522) of all saturated fatty acids, is regarded as an essential flavor component of Limburger cheese (575). ( )-3-Methyl-2-hexenoic acid was recognized as the malodorous component of schizophrenics sweat (579). The undesirable odor of mutton can be attributed to branched-chain and unsaturated fatty acids having 8 to 10 carbon atoms. The 4-methyl-branched acids and in particular 4-methyloctanoic and 4-methyl-... 

R. T. Marsih, N. Miller, G. J. Kilmer, and R. E. Simmons, Identification and quantitation of the primary chemicals responsible for the characteristic malodor of heet sugar by purge and trap GC-MS-OD techniques, J. Chromatogr. Sci. 32(5) 165 (1994). 

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