CHM 120 Isolation of Organic Compounds

Sources of Organic Compounds

• The leading sources are

i) Coal is formed from wood millions of years ago through the following coalification stages: wood peat lignite subbituminous coal bituminous coal anthracite coal

ii) Petroleum (crude oil) and Natural gas – organic compounds can be obtained from petroleum (crude oil) which contains mainly saturated, unsaturated and aromatic hydrocarbons.

Solvent Extraction

• Coal is extracted by digestion with solvents such as tetracloromethane, acetone, pyridine, alcohols, benzene or mixed solvent systems at atmospheric pressure in a stirred extraction vessel.

• Organic compounds that can be extracted from coal include alkylbenzenes, phenols and polunuclear aromatics.

• The yield and the composition of the extract depend on the coal type (lignite, sub – bituminous, bituminous, anthracite) and source, the solvent or solvent mixture used and the conditions of extraction (e.g length of time, temperature, pressure and particle size of the coal).