The use of solvents for purifying industrial naphthalene from coal tar distilled oils

The organic chemistry industry is based on organic compounds derived from coal, petroleum and gas. Coal tars derived from the carbonisation process are complex mixtures, of which the polycyclic aromatic hydrocarbons (PAH's) are the main component. One of the most important PAH's is naphthalene, which represents between 10 to 12% of the sample. In recent years, new applications for industrial naphthalene have been developed. However, the naphthalene required for high level industry must be extremely pure. New routes in the purification process are being studied to reduce the economic cost and environmental impact resulting from the increase in demand for pure naphthalene. Any alternative method to that of sublimation for purification in the distillation process and/or catalytic hydrogenation must improve the quality of industrial naphthalene, to make it suitable for the new applications. In the present work, an alternative method for purifying industrial naphthalene has been investigated. A new process based on extraction with solvents such as phosphoric acid and acetic acid is reported and discussed. Industrial naphthalene was purified by means of a new technique and the stability and good properties of the product were verified.