BUTENE-l

A new process developed by Institut Francais du Petrole produces butene-l (l-butene) by dimerizing ethylene.  A homogeneous catalyst system based on a titanium complex is used. The reaction is a concerted coupling of two molecules on a titanium atom, affording a titanium (IV) cyclic compound, which then decomposes to butene-l by an intramolecular β-hydrogen transfer reaction.

Figure 1.1 A flow diagram of the Institute Francais du Petrole process for producing 1-butene from ethylene.

The Alphabutol process (Figure 7–8) operates at low temperatures (50–55°C) and relatively low pressures (22–27 atm). The reaction occurs in the liquid phase without a solvent. The process scheme includes four sections: the reactor, the co-catalyst injection, catalyst removal, and distillation.

The continuous co-catalyst injection of an organo-basic compound deactivates the catalyst downstream of the reactor withdrawal valve to limit isomerization of l-butene to 2-butene. Table 1.1 shows the feed and product quality from the dimerization process.

Table 1.1 : Feed and product quality from dimerization of ethylene to 1-butene