Air Pollutants

Butane is a gas with the formula C₄H₁₀ that is an alkane with four carbon atoms. The term may refer to any of two structural isomers, or to a mixture of them: in the IUPAC nomenclature, however, butane refers only to the unbranched n-butane isomer; the other one being called “methylpropane” or isobutane.

Butanes are highly flammable, colorless, easily liquefied gases. The name butane comes from the roots but- (from butyric acid) and -ane.

Butanone, also known as methyl ethyl ketone or MEK, is an organic compound with the formula CH₃C(O)CH₂CH₃. This colorless liquid ketone has a sharp, sweet odor reminiscent ofbutterscotch and acetone. It is produced industrially on a large scale, and also occurs in trace amounts in nature.^[2] It is soluble in water and is commonly used as an industrial solvent.^[3]

n-Butyl acetate, also known as butyl ethanoate, is an organic compound commonly used as a solvent in the production of lacquers and other products. It is also used as a synthetic fruit flavoring in foods such as candy, ice cream, cheeses, and baked goods. Butyl acetate is found in many types of fruit, where along with other chemicals it imparts characteristic flavors. It is a colourless flammable liquid with a sweet smell of banana.

The other three isomers of butyl acetate are: isobutyl acetate, tert-butyl acetate, and sec-butyl acetate.

Any of the four isomeric alcohols of formula C₄H₉OH:

• n-Butanol, butan-1-ol, 1-butanol, n-butyl alcohol;
• Isobutanol, 2-methylpropan-1-ol, isobutyl alcohol;
• sec-Butanol, butan-2-ol, 2-butanol, sec-butyl alcohol;
• tert-Butanol, 2-methylpropan-2-ol, tert-butyl alcohol.

It can also refer to butanol fuel, a proposed alternative to gasoline.

An aldehyde  is an organic compound containing a terminal carbonyl group.This functional group, which consists of a carbon atom bonded to ahydrogen atom and double-bonded to an oxygen atom (chemical formulaO=CH-), is called the aldehyde group . The aldehyde group is also calledthe formyl  or methanoyl  group.

The word aldehyde  seems to have arisen from al cohol dehyd rogenated .In the past, aldehydes were sometimes named after the correspondingalcohols, for example, vinous aldehyde  for acetaldehyde. ( Vinous  is fromLatin vinum  = wine, the traditional source of ethanol; compare vinyl.)

The aldehyde group is polar. Oxygen, more electronegative than carbon,pulls the electrons in the carbon-oxygen bond towards itself, creating anelectron deficiency at the carbon atom.

Owing to resonance stabilization of the conjugate base, an Î±-hydrogen in analdehyde is more acidic than a hydrogen atom in an alkane, with a typicalpKa of 17.

Butoxyethanol is an organic solvent with the formula BuOC₂H₄OH (Bu = CH₃CH₂CH₂CH₂). It is a colorless liquid with a sweet, ether-like odour. It is a butyl ether of ethylene glycol. It is a relatively nonvolatile, inexpensive solvent with modest surfactant properties.

1-Chlorobutane is an alkyl halide with the chemical formula C₄H₉Cl. It reacts with lithium metal to give n-butyllithium:^[1]

2 Li + C₄H₉Cl → C₄H₉Li + LiCl

Methyl tert-butyl ether, also known as methyl tertiary butyl ether and MTBE, is an organic compound with molecular formula (CH₃)₃COCH₃. MTBE is a volatile, flammable, and colorless liquid that is immiscible with water. It has a minty odor vaguely reminiscent of diethyl ether, leading to unpleasant taste and odor in water. MTBE is a gasoline additive, used as an oxygenate to raise the octane number. Its use is controversial in the US and declining in that country in part because of its occurrence in groundwater and legislation favoring ethanol. Worldwide production of MTBE has been constant at about 18 million tons/y (2005) owing to growth in Asian markets which are less subject to ethanol subsidies

Butanethiol, also known as butyl mercaptan, is a volatile, clear to yellowish liquid with a fetid (extremely foul-smelling) odor, commonly described as “skunk” odor. In fact, butanethiol is structurally similar to several major constituents of a skunk’s defensive spray. The scent of butanethiol is so strong that the human nose can easily detect it in the air at concentrations as low as 10 parts per billion.

In chemistry, butylene may be an alternate name for the hydrocarbon butene, C₄H₈. It is also a divalent functional group with formula C₄H₈^2• that can be seen as the result of removing two hydrogen atoms from a butane molecule, leaving two free bonds.

There are several isomers of butylene, depending on the starting isomer of butane and the positions of the free bonds:

• From straight-chain butane (n-butane):
  • 1,1-Butylene
  • 1,2-Butylene
  • 2,2-butylene
  • 1,3-Butylene
  • 2,3-Butylene (which has two stereoisomers, cis and trans)
  • 1,4-Butylene
• From branched butane (isobutane, methylpropane):
  • 1,1-Isobutylene
  • 1,2-Isobutylene
  • 1,3-Isobutylene