Warning odors

Formula C2H2AsC13 Description Oily, colorless liquid Warning Odor like geraniums Molecular weight 207.32. 

The aposematic beetle, Metriorrhynchus rhipidius, contains three pyrazines as warning odor components and two amides as bitter principles (Tables III, V, and VIII) (97). Of the three components with the beetlelike odor, the most characteristic is 2-methoxy-3-isopropylpyrazine (24b). The other two components are 2-methoxy-3-methylpyrazine (24a) and 2-methoxy-3-sec-butylpyrazine (24d). It would seem likely that these compounds will occur in the defensive systems of the aposematic beetles. The two amide components, detectable in the hemo-lymph exuded by adult beetles, are 3-phenylpropanamide (130) and l-methyl-2-quinolone (57), the latter being the major component. It seems likely that these bitter principles contribute to distastefulness to potential predators. 

Warning odor which betrays ita presence before toxic effects are proHiieed. 

Use Solvent for lacquers and paints, extraction of penicillin, photographic film, leather polishes, nail polish, warning odor, flavoring agent, printing and finishing fabrics, solvent for phosphors in fluorescent lamps. 

Properties Colorless, flammable gas or liquid almost odorless. Autoign temp 900-1100F, heating value 1000 Btu/ft3. A warning odor is added to household fuel gas as a safety precaution. 

Products and Uses A warning odorant with a distinctive aroma, used in natural gas by power companies. Power companies use one drop for every 1000 cubic feet. The normal nose can smell less than 1%. At 7% the gas is explosive. 

Methyl bromide is a colorless liquid or gas with practically no odor. It is a poisonous gas at room temperature and atmospheric pressure. At high concentrations, it has a chloroform-like odor. Detection of lower concentrations is often facilitated by a warning odorant, chloropicrin, which is added by the manufacturer. 

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