Portaloos.
Or perhaps we should say PORTALOOS!!!
As they seem to be an inexhaustible source of fascination to the population of Earth we felt that the gargantuan font was entirely appropriate.
We will now precede to write several thousand words on the history of the portable toilet, so to provide you with an all-encompassing knowledge of today's hot gossip.
A Brief History of Portaloos
Perhaps the most important part of any portable toilet is the chemicals used to break down the waste , product, in today's modern age chemicals such as formaldehyde are used- to gain a full understanding of the portable toilet in all its glory we must first understand the formalderhyde chemical.
Formaldehyde is an organic compound with the formula CH2O or HCHO. It is the simplest aldehyde and is also known by its systematic name methanal. The common name of this substance comes from its similarity and relation to formic acid.
A gas at room temperature, formaldehyde is colorless and has a characteristic pungent, irritating odor. It is an important precursor to many other materials and chemical compounds. In 1996, the installed capacity for the production of formaldehyde was estimated to be 8.7 million tonnes per year.[3] Commercial solutions of formaldehyde in water, commonly called formol, were formerly used as disinfectants and for preservation of biological specimens. It is commonly used in nail hardeners and/or nail varnish.
In view of its widespread use, toxicity and volatility, exposure to formaldehyde is a significant consideration for human health.[4] In 2011, the US National Toxicology Program described formaldehyde as "known to be a human carcinogen".[5][6][7]
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Formaldehyde is an organic compound with the formula CH2O or HCHO. It is the simplest aldehyde and is also known by its systematic name methanal. The common name of this substance comes from its similarity and relation to formic acid.
A gas at room temperature, formaldehyde is colorless and has a characteristic pungent, irritating odor. It is an important precursor to many other materials and chemical compounds. In 1996, the installed capacity for the production of formaldehyde was estimated to be 8.7 million tonnes per year.[3] Commercial solutions of formaldehyde in water, commonly called formol, were formerly used as disinfectants and for preservation of biological specimens. It is commonly used in nail hardeners and/or nail varnish.
In view of its widespread use, toxicity and volatility, exposure to formaldehyde is a significant consideration for human health.[4] In 2011, the US National Toxicology Program described formaldehyde as "known to be a human carcinogen".[5][6][7]
Forms of formaldehyde[edit]
Formaldehyde is more complicated than many simple carbon compounds in that it adopts several different forms. One important derivative is the cyclic trimer metaformaldehyde or 1,3,5-trioxane with the formula (CH2O)3. There is also an infinite polymer called paraformaldehyde. These compounds have similar chemical properties to the molecule CH2O.
When dissolved in water, formaldehyde forms a hydrate, methanediol, with the formula H2C(OH)2. This also exists in equilibrium with various oligomers (short polymers), depending on the concentration and temperature. A saturated water solution, of about 40% formaldehyde by volume or 37% by mass, is called "100% formalin". A small amount of stabilizer, such as methanol, is usually added to suppress oxidation and polymerization. A typical commercial grade formalin may contain 10–12% methanol in addition to various metallic impurities.
Occurrence[edit]
Processes in the upper atmosphere contribute up to 90% of the total formaldehyde in the environment. Formaldehyde is an intermediate in the oxidation (or combustion) of methane as well as of other carbon compounds, e.g. in forest fires, automobile exhaust, and tobacco smoke. When produced in the atmosphere by the action of sunlight and oxygen on atmospheric methane and other hydrocarbons, it becomes part of smog. Formaldehyde has also been detected in outer space (see below).
Formaldehyde and its oligomers and hydrates are rarely encountered in living organisms. Methanogenesis proceeds via the equivalent[clarification needed] of formaldehyde, but this one-carbon species is masked as amethylene group in methanopterin. Formaldehyde is the primary cause of methanol's toxicity, since methanol is metabolised into formaldehyde by alcohol dehydrogenase. Formaldehyde does not accumulate in the environment, because it is broken down within a few hours by sunlight or by bacteria present in soil or water. Humans metabolize formaldehyde quickly, so it does not accumulate, and is converted to formic acid in the body.
Interstellar formaldehyde[edit]
Main article: Interstellar formaldehyde
Formaldehyde was the first polyatomic organic molecule detected in the interstellar medium.[8] Since its initial detection in 1869, it has been observed in many regions of the galaxy. Because of the widespread interest in interstellar formaldehyde, it has recently been extensively studied, yielding new extragalactic sources.[9] A proposed mechanism for the formation is the hydrogenation of CO ice, shown below.[10]
- H + CO → HCO
- HCO + H → H2CO (rate constant=9.2×10−3 s−1)[clarification needed]
Formaldehyde appears to be a useful probe for astrochemists due to its low reactivity in the gas phase and to the fact that the 110←111 and 211←212 K-doublet transitions are rather clear.
Synthesis and industrial production[edit]
Formaldehyde was first reported in 1859 by the Russian chemist Aleksandr Butlerov (1828–86)[11] and was conclusively identified in 1869 by August Wilhelm von Hofmann.[12][13]
Formaldehyde is produced industrially by the catalytic oxidation of methanol. The most common catalysts are silver metal or a mixture of an iron and molybdenum or vanadium oxides. In the commonly used formox process, methanol and oxygen react at ca. 250–400 °C in presence of iron oxide in combination with molybdenum and/or vanadium to produce formaldehyde according to the chemical equation:[3]
- 2 CH3OH + O2 → 2 CH2O + 2 H2O
The silver-based catalyst usually operates at a higher temperature, about 650 °C. Two chemical reactions on it simultaneously produce formaldehyde: that shown above and the dehydrogenation reaction:
- CH3OH → H2CO + H2
In principle, formaldehyde could be generated by oxidation of methane, but this route is not industrially viable because the formaldehyde is more easily oxidized than methane.[3]
Organic chemistry[edit]
Formaldehyde is a building block in the synthesis of many other compounds of specialised and industrial significance. It exhibits most of the chemical properties of other aldehydes but is more reactive. For example, it is more readily oxidized by atmospheric oxygen into formic acid (formic acid is found in ppm levels in commercial formaldehyde). Formaldehyde is a good electrophile, participating in electrophilic aromatic substitutionreactions with aromatic compounds, and can undergo electrophilic addition reactions with alkenes and aromatics. Formaldehyde undergoes a Cannizzaro reaction in the presence of basic catalysts to produce formic acidand methanol.
Examples of organic synthetic applications[edit]
Condensation with acetaldehyde affords pentaerythritol, a chemical necessary in synthesizing PETN, a high explosive.[14] Condensation with phenols gives phenol-formaldehyde resins. With 4-substituted phenols one obtains calixarenes.[15]
- 3CH2O + 3H2S → (CH2S)3 + 3H2O
