Discussion of Industrial Synthetic Routes to
Robert G. Syvret, Ph.D., ACSF
Various synthetic routes are known for the formation and industrial scale production of hexafluoro-1,3-butadiene (HFBD), C4F6. This document provides a brief overview and comparison of the key attributes of the most prominent industrial routes.
A preferred and advantageous route to C4F6, involving addition of the interhalogen, ICl, to chlorotrifluoroethylene (CTFE) followed by subsequent coupling and dehalogenation is presented first, followed thereafter by several alternative and less advantageous routes to C4F6, each with their own inherent problems.
Route 1: Preferred Route to C4F6 from ICl/Chlorotrifluoroethylene CTFE
A preferred route to C4F6 involves the readily available raw materials ICl and CTFE in a 3-step synthetic process as illustrated below in Scheme 1. The basis of this chemistry has been known for nearly 70 years and was described in the past scientific literature by several workers including Hazeldine (J. Chem. Soc (1952) 4423), Hauptschein (JACS (1961) 83, 2495), and Ameduri (J. Fluorine Chem. (1995) 74, 261). Moreover, similar process chemistry is described in the Russian Patents, RU 2246477 and RU 2272017.