Fig. 1From: Butadiene sulfone as ‘volatile’, recyclable dipolar, aprotic solvent for conducting substitution and cycloaddition reactionsThermally induced retro-cheletropic switch enabling the recyclability of piperylene sulfone (top) and butadiene sulfone (bottom). Piperylene sulfone melts at −12 °C, making it a liquid at room temperature while butadiene sulfone is a stable solid that melts at 64 °CBack to article page