Germanium catalysts for hydrosilylations & siloxane couplings

Hydrosilylations and siloxane coupling reactions are generally catalysed using precious metal catalysts. Apart from the cost issue regarding precious metals, platinum based catalysts especially are also known to cause discoloration of silicon products after a certain amount of time. Germanium catalysts have been known scientifically, but the ones used so far are based on demanding and expensive synthesis routes and cannot be used in oxygen-free conditions.

The new Germanium (II) catalysts are produced in a simple one-pot synthesis from germanocen (CP2Ge) and acidic boranates with high yields. The inventors showed that storing the catalyst unprotected for three weeks in an uncovered vessel open to room air caused no detectable degradation of the catalyst. Upscaling of the catalyst production is assumed to be uncomplicated, since no special reaction equipment or plant technology is needed. Purification of the catalyst from the reaction medium can be done easily and cost-efficiently by evaporating the volatile by-products.

Catalyst for hydrosilylations and siloxane couplings, for the production of a broad range of industrial silicone products.

Catalyst produced and tested in lab scale (< 1 g). The inventors expect no difficulties with up-scaling. Stability/storability was tested for 3 weeks, unprotected in ambient conditions: no degradation was detected in follow-up analysis.