APPLICATION OF MICROWAVE-ENERGY TO CLEAVAGE OF SULFUR BONDS IN THE S-8 RING IN THE SIMPLEST AMIDE SOLVENTS

Microwave energy has been employed for cleavage of sulfur bonds in the S-8 ring. Cleavage of S-S bonds was carried out in extraction of elem ental sulfur in simple amide solvents. Due to the use of microwave ene rgy and the polarity of amides, up to, 100 times lower concentration o f a nucleophilic reducer, such as azide or nitrite, may be used to cle ave the sulfur bonds. The time needed for cleavage of sulfur bonds at sulfur concentration higher than 0.1 mg S/100 mg solvent was reduced f rom hours to minutes. This cleavage was quantitative when carried out in a Teflon container in a microwave oven with continuous or pulsed he ating. UV spectra show from which value of absorption there will be a sulfur sol at different sulfur concentrations. This allows us to adjus t the microwave exposure power and time to avoid sulfur sol formation and not destroy the sample. (C) 1996 Academic Press, Inc.