Faculty of engineering

WS 2015/16

29. March ĘC 15. April 2016


Recycling routes for Triphenylphosphine (TPP)


Koninklijke DSM N.V.

Dr. Marco Haumann




Triphenylphosphane (TPP) is a key component in the Wittig reaction. This reaction is used in the production of olefins, especially vitamins and carotenoids, and therefore plays a major role in industry. As by-product of this reaction the oxide of TPP called triphenylphosphine oxide (TPPO) is formed in stoichiometric amounts.


Due to economic and sustainability concerns TPPO should be processed and recycled to regain TPP. The reduction of TPPO can be carried out either in a one-step or in a two- or multi-step process. For the direct reduction of TPPO in a one-step process, procedures using strong and expensive reducing agents and high temperatures are known. Two- or multi-step procedures however allow economically more feasible processes. Worth mentioning are processes which convert TPPO into triphenylphosphine dichloride (DCP), for instance with the help of phosgene. DCP is easier to reduce than TPPO and can be transformed to TPP either catalytically or with reducing agents like silanes.


For the proposed process route, complete process concepts have to be developed, process equipment has to be designed and production costs have to be determined and compared. Your considerations have to be based on a minimal capacity of 1000 t of TPP per year with 8000 operating hours per year. The different process routes have to be evaluated regarding their cost effectiveness.



Figure 1: Groups and tasks