unsaturated hydrocarbons

Examples of unsaturated hydrocarbons in the following topics:

• Alkenes & Alkynes

  • Alkenes and alkynes are hydrocarbons which respectively have carbon-carbon double bond and carbon-carbon triple bond functional groups.
  • The molecular formulas of these unsaturated hydrocarbons reflect the multiple bonding of the functional groups:
  • As noted earlier in the Analysis of Molecular Formulas section, the molecular formula of a hydrocarbon provides information about the possible structural types it may represent.

• Substitution Reactions of Benzene and Other Aromatic Compounds

  • The remarkable stability of the unsaturated hydrocarbon benzene has been discussed in an earlier section.

• Introduction to Hydrocarbons

  • Hydrocarbons are the simplest class of organic compounds, consisting solely of hydrogen and carbon.
  • Hydrocarbons are the simplest class of organic compounds and are composed solely of hydrogen and carbon.
  • This class can be further divided into two groups: aliphatic hydrocarbons and aromatic hydrocarbons.
  • Alkenes and alkynes are known as unsaturated hydrocarbons because some of the carbons are connected to fewer than four neighboring atoms.
  • The study of hydrocarbons is particularly important to the fields of chemical and petroleum engineering, as a variety of hydrocarbons can be found in crude oil.

• Alkanes

  • Alkanes are relatively unreactive hydrocarbons that contain no double or triple bonds in their carbon skeletons.
  • Alkanes, also called paraffins, are a class of hydrocarbons that are fully saturated with hydrogen.
  • This is in contrast to alkenes and alkynes, which contain double and triple bonds and are known as unsaturated hydrocarbons.
  • Alkanes are named with the suffix "-ane" following the hydrocarbon prefixes.

• Properties of Aromatic Compounds

  • Aromatic compounds, originally named because of their fragrant properties, are unsaturated hydrocarbon ring structures that exhibit special properties, including unusual stability, due to their aromaticity.
  • Poly-aromatic hydrocarbons are components of atmospheric pollution and are known carcinogens.

• Lipid Molecules

  • Fatty acids may be saturated or unsaturated.
  • When the hydrocarbon chain contains a double bond, the fatty acid is said to be unsaturated.
  • Oleic acid is an example of an unsaturated fatty acid.
  • Unsaturated fats or oils are usually of plant origin and contain cis unsaturated fatty acids.
  • Unsaturated fatty acids have one or more double bonds.

• Other Aromatic Compounds

  • Many unsaturated cyclic compounds have exceptional properties that we now consider characteristic of "aromatic" systems.The following cases are illustrative:
  • Furan and pyrrole react more rapidly with bromine, but they also give substitution products.This tendency to favor substitution rather than addition suggests that the parent unsaturated ring system has exceptional stability.
  • The first example is azulene, a blue-colored 10 π-electron aromatic hydrocarbon isomeric with naphthalene.
  • Remarkably, this hydrocarbon is chemically unstable, in contrast to most other aromatic hydrocarbons.
  • Formulation of the Hückel rule prompted organic chemists to consider the possible aromaticity of many unusual unsaturated hydrocarbons.

• Anoxic Hydrocarbon Oxidation

  • Anoxic hydrocarbon oxidation can be used to degrade toxic hydrocarbons, such as crude oil, in anaerobic environments.
  • Hydrocarbons are organic compounds consisting entirely of hydrogen and carbon.
  • The combustion of hydrocarbons is the primary energy source for current civilizations.
  • Although it was once thought that hydrocarbon compounds could only be degraded in the presence of oxygen, the discovery of anaerobic hydrocarbon-degrading bacteria and pathways show that the anaerobic degradation of hydrocarbons occurs naturally.
  • Microbes may be used to degrade toxic hydrocarbons in anaerobic environments.

• Aerobic Hydrocarbon Oxidation

  • Microbes can utilize hydrocarbons via a stepwise oxidation of a hydrocarbon by oxygen produces water and, successively, an alcohol, an aldehyde or a ketone, a carboxylic acid, and then a peroxide.
  • Note the presence of oxygen, thus defining this as aerobic hydrocarbon oxidation.
  • There are examples of anaerobic hydrocarbon oxidation, which will not be discussed here.
  • Biosurfactants enhance the emulsification of hydrocarbons, have the potential to solubilize hydrocarbon contaminants, and increase their availability for microbial degradation.
  • Discuss the advantages of organisms that can undergo aerobic hydrocarbon oxidation

• Irreversible Addition Reactions

  • If substituent Y is a hydrogen, an alkyl group or an aryl group, the resulting alcohol is a stable compound and does not decompose with loss of hydrogen or hydrocarbons, even on heating.
  • Reduction of α,β-unsaturated ketones by metal hydride reagents sometimes leads to a saturated alcohol, especially with sodium borohydride.
  • These reagents are powerful nucleophiles and very strong bases (pKa's of saturated hydrocarbons range from 42 to 50), so they bond readily to carbonyl carbon atoms, giving alkoxide salts of lithium or magnesium.