Oligomerization of alkenes

Instituto de Tecnologia Quinica, UPV, Av. Naranjos s/n, E-46022 Valencia, Spain 

1 Medium pore zeolites influence of crystal size and acid site density.. . 127 

Catalysts for Fine Chemical Synthesis, Vol. 4, Microporous and Mesoporous Solid Catalysts Edited by E. Derouane 2006 John Wiley Sons, Ltd 

---

The major disadvantage of the alkylation process is that acid is consumed in considerable quantities (up to 100 kg of acid per ton of product). Hence, solid acids have been explored extensively as alternatives. In particular, solid super acids such sulfated zirconia SO/ IZr02) show excellent activities for alkylation, but only for a short time, because the catalyst suffers from coke deposition due to oligomerization of alkenes. These catalysts are also extremely sensitive to water. 

Hsia Chen, C.S. and Bridget, R. (1995) Shape-selective oligomerization of alkenes to near-linear hydrocarbons by zeolite catalysis. J. Catal., 161, 587-593. 

The soluble nickel catalyst developed by IFP for the oligomerization of alkenes applied in different Dimersol processes (see Section 13.1.3) can also be used in benzene hydrogenation to replace Raney nickel (IFP cyclohexane process).340... 

All the reactions described so far are important for elucidating the mechanism of oligomerization of alkenes catalyzed by nickel(O) complexes. 

Ziegler-Natta-type catalysts, which are active in polymerization and oligomerization of alkenes. are also influenced by adding CO2 to the reaction mixture. The addition of CO2 changes the molecular we t and crystallinity of the products or the activity and selectivity of the catalyst, both in polyethylene [307,308] and in polypropylene production [309-312]. 

Dehydration of alcohols over solid catalysts can yield alkenes by intramolecular dehydration, whereas ethers are the product of an intermolecular process. The catalysts used can be acidic or basic solids or bifunctional acid-base materials. Although selective synthesis of any desired product is possible, complications can arise as a result of side-reactions-dehydrogenation and decomposition of the starting alcohol, decomposition and consecutive transformations of intermediates and products (j9-cleavage of carbocations, oligomerization of alkenes). 

P.W. Jolly (1982) Nickel catalyzed oligomerization of alkenes and related reactions in Comprehensive Organometallic Chemistry, eds G. Wilkinson, F.G.A. Stone and E.W. Abel, Pergamon, Oxford, vol. 8, p. 615. 

Similar reactions are observed over other strongly acidic catalysts, such as AICI3 and SbF . The acidic catalysts also promote dimerization and oligomerization of alkenes by mechanisms that are well known in the solution chemistry of carbocations. ... 

---