Gallium-catalyzed recycling of silicone waste with boron trichloride to yield key chlorosilanes

Chemical recycling to monomers is a key strategy for a sustainable circular polymer economy. However, most efforts have focused on polymers with carbon backbones. Recycling of silicone polymers and corresponding materials, featuring a robust inorganic backbone and tunable properties, remains in its infancy. We present a general method for depolymerization of a very wide range of silicone-based materials and postconsumer waste, including end-of-life cross-linked polydimethylsiloxane-based networks within formulated materials. The reaction proceeds at 40°C, harnessing an efficient gallium catalyst for a million-fold rate enhancement and boron trichloride as the chlorine source, to produce nearly quantitative yields of (methyl)chlorosilanes, key intermediates in the Müller-Rochow process that anchors the silicone industry.