Chemicals Used
Typically, lower molecular weight volatile organic compounds are used. Generally the higher molecular weight for a given class of compounds, the lower volatility and initial concentration but the longer persistence. Some chemicals (typically thiols) have a certain concentration threshold over which the smell is not perceived significantly stronger; therefore a lower-volatility compound is capable of providing comparable stench intensity to a higher-volatility compound, but for longer time. Another issue is the operating temperature, on which the compound's volatility strongly depends. Care should be taken as some compounds are toxic either in higher concentration or after prolonged exposure in low concentration.
Some plants may be used as improvised stink bombs, One such plant is the Parkia speciosa or 'stinky bean', which grows in India, Southeast Asia and Eastern Australia. The pods from this plant are collected when partly dried and stamped on, to release the stink.
The most often encountered compounds are:
- Mercaptans
- Methanethiol (used rarely; it is a gas and therefore more difficult to handle than liquids)
- Ethanethiol
- Propanethiol
- Butanethiol
- Pentanethiol
- Other sulfur compounds
- Hydrogen sulfide, smelling of rotten eggs
- Ammonium sulfide, rotten eggs
- Carboxylic acids
- Propionic acid, sweat
- Butyric acid, rancid dairy
- Valeric acid
- Caproic acid, smelling of cheese
- Aldehydes
- Amines
- Ethylamine, fishy smell
- Putrescine, rotten meat
- Cadaverine, rotten meat
- Heterocyclic compounds
- Indole
- Skatole, smelling of feces
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