|
Methanol, also known as methyl alcohol, carbinol, wood alcohol, wood naphtha or wood spirits, is a toxic chemical with chemical formula CH3OH (often abbreviated MeOH). Drinking even small amounts can cause blindness. It is the simplest alcohol, and is a light, volatile, colourless, flammable, toxic liquid with a distinctive odor that is very similar to but slightly sweeter than ethanol (drinking alcohol).[1] At room temperature it is a polar liquid and is used as an antifreeze, solvent, fuel, and as a denaturant for ethanol. It is also used for producing biodiesel via transesterification reaction.
Methanol is produced naturally in the anaerobic metabolism
of many varieties of bacteria, and is ubiquitous in the environment. As
a result, there is a small fraction of methanol vapor in the
atmosphere. Over the course of several days, atmospheric methanol is oxidized by oxygen with the help of sunlight to carbon dioxide and water.
Methanol burns in air forming carbon dioxide and water:
- 2 CH3OH + 3 O2 → 2 CO2 + 4 H2O
A methanol flame is almost colorless in bright sunlight conditions,
causing an additional safety hazard around open methanol flames.
Because of its toxic properties, methanol is frequently used as a
denaturant additive for ethanol manufactured for industrial uses— this
addition of methanol economically exempts industrial ethanol from the
rather significant 'liquor' taxes that would otherwise be levied as it
is the essence of all potable alcoholic beverages. Methanol is often
called wood alcohol because it was once produced chiefly as a byproduct
of the destructive distillation of wood. It is now produced
synthetically by a multi-step process: natural gas or coal gas
and steam are reformed in a furnace to produce hydrogen and carbon
monoxide; then, hydrogen and carbon monoxide gases react under pressure
in the presence of a catalyst. Methanol is also produced from the
gasification of a range of renewable biomass materials, such as wood
and black liquor from pulp and paper mills.
|
