VATIS UPDATE Article

Researchers at Durham University, the United Kingdom, have developed a method breaking down rubber in materials at room temperature. The chemical process uses catalytic disassembly, saving energy over processes requiring heating the rubber. The Durham researchers believe that their chemical process may be used to allow the materials to be recycled back into their original use – so a recycled tire could be made into a new tire. Their cross metathesis reaction breaks down rubbery polymers into viscous liquids that can then be reformed without degradation.

Previously this was not possible so the tires were broken down into fuel or small rubber particles added to building materials or used in road construction. The process discovered uses Grubbs’ catalysts to break down polybutadiene (PBd) networks at their double bonds via cross-metathesis (CM) reactions to produce readily soluble molecules. As the chains fragment, the material disintegrates into rubber crumb at room temperature. Grubbs’ catalysts are easily synthesized and readily-available commercially.

Grubbs’ Catalysts are a series of transition metal carbene complexes used as catalysts for olefin metathesis. They are named after Robert H. Grubbs, the chemist who first synthesized them. There are two generations of the catalyst, as shown on the right. In contrast to other olefin metathesis catalysts, Grubbs’ catalysts tolerate other functional groups in the alkene, are air-tolerant and are compatible with a wide range of solvents. For these reasons, Grubbs’ catalysts have become popular in synthetic organic chemistry.