A ring that contains at least one heteroatom (an atom other than carbon) is called a heterocycle, and a substance based on a heterocyclic ring is a heterocyclic compound. Heterocyclic compounds containing N, O or S are by far the most common

The most characteristic reactions of benzenoid arenes are the substitution reactions that occur when they react with electrophilic reagents. The electrophiles are either a positive ion (E+) or some other electron-deficient species with a large partial positive charge

More reactive than benzene toward electrophilic substitution NO2 An deactivating group Less reactive than benzene toward electrophilic substitution Ortho-para director Meta director

17.1 The Acidity of the α Hydrogens of Carbonyl Compounds: Enolate Anions 17.2 Keto and Enol Tautomers 17.3 Reactions via Enols and Enolate Anions

Phenols are like alcohols in being able to form strong intermolecular hydrogen bonds. Phenols have higher boiling points than hydrocarbons of the same molecular weight. A modest solubility in water

Quinones are an interesting and valuable class of compounds because of their oxidation-reduction, or redox, properties. The redox properties of quinones are important to the functioning of living cells, where compounds called ubiquinones(泛醌) act as biochemical oxidizing agents to mediate the electro-transfer processes involved in energy production

Functional groups The structural features that make it possible to classify compounds by reactivity are called functional groups. A functional group is a part of a larger molecule and is composed of an atom or a group of atoms that have a characteristic chemical behavior. The Chemistry of every organic molecules

An acid is a substance that can donate (or lose) a proton, A base is a substance that can accept (or remove) a proton

Energy and the Relative Stability Kinetic energy is the energy an object has because of its motion. Potential energy is stored energy. It exists only when an attractive or repulsive force exists between objects

The primary source of alkanes is petroleum Natural gas consists chiefly of methane, but ethane, propane, butane, and isobutane are also present. Petroleum is a complex mixture of hydrocarbons that must be refined into different fraction before it can be used