Lindane (γ-1,2,3,4,5,6-hexachlorocyclohexane, ɣ-HCH), which was used as pesticide in the XX century has become an important environmental problem since during its production, besides the gamma stereoisomer, different HCH stereoisomers and other chlorinated compounds were produced (85-92% wt.). All this waste was disposed of in landfills over different countries of European Union, assuming a risk for human health and the environment. Our research project includes the study of different transformations of concentrated residues of the different isomers of HCH to obtain useful products with a higher added value in a sustainable way. One of the studied reactions is the dehydrochlorination of the HCH (figure 1: basic dehydrochlorination of HCH.) with bases in order to obtain a mixture of trichlorobenzenes (TCB) which, subsequently, would be transformed in different products. In this study of the dehydrodechlorination reaction, bases of different nature were used, playing also with their solubility in different solvents and at different temperatures. An important effect of the solvent and the strength and solubility of the base was observed, affecting reaction rate and yield, It has been possible to optimize the procedure described in the literature using NaOH. Total conversions in short times have been reached optimizing the different parameters of the reaction. Reactions with real samples from the production waste have been also tested in order to check the applicability of the developed strategy.

Resumen del póster presentado a la XXXVIII Reunión Bienal de la Real Sociedad Española de Química, celebrada en el Palacio de Congresos de Granada, del 27 de junio al 30 de junio de 2022.

Peer reviewed