Gallium-catalyzed boron-assisted recycling of silicone waste yields 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 post-consumer waste, including end-of-life crosslinked 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.

Methods
All raw data is made available to be able to process again spectroscopic and chromatographic analyses and characterization, using standard softwares for processing.

Supplementary Materials of the original Science magazine publication include all materials and methods.