Introduction

A green, solvent, metal and additive free process for the chlorination of toluenes is reported. The proposed methodology can be carried out by the exclusive use of sunlight. It is characterized by a low environmental and economic impact. The method avoids the use of corrosive, toxic and difficult handle reagents, as HCl and Cl2 gas. The method allows a considerable simplification of industrial plant engineering, the use of low cost reagents and low energy consumption.

Technical features

Currently the industrial processes of chlorination of the alpha position of substituted toluenes involve the use of highly corrosive reagents such as HCl and Cl2 (gas), a considerable energy expenditure (heat) and run with very modest yields and conversions. The present process allows the chlorination in alpha position of toluenes variously substituted in green conditions. The process is carried out simply by mixing the alkyl arene and the trichloroisocyanuric acid, in a stoichiometric ratio of 3: 1 in a reactor and exposing the mixture to irradiation, at room temperature and under stirring; the reaction product is obtained in very high yields and conversions and with a very high degree of purity. Irradiation can be carried out either with a solar simulator, with blue LEDs, or sunlight. The reaction runs in the total absence of solvents and catalysts and of any additive.

Possible Applications

• Industrial preparations;
• Amphetamine-based drugs;
• Artificial resins;
• Fuel additives;
• Solutions for photographic development.

Advantages

• “Green” and solvent free process;
• Mild reaction conditions;
• Very high economy atom;
• Synthesis of high value-added products;
• Considerable simplification of industrial plant engineering;
• Very high process economy in terms of reactants and energy.