Dimers and codimers of olefins

Olehns with four to eight carbon atoms can be obtained by dimerization and codimerization of ethylene, propylene and butenes. 

Although it can be carried out with Ziegler type catalysts, and is hence widely investigated in the laboratory, this conversion only reached the industrial stage in 19S5. 

The dimerization of ethylene, according to whether the frnal product is pure 1-butene or a mixture of n-fautenes, exists in two industrial versions  

In the presence of triethylalununum, the Goodyear-Scientific Design process produces 2-methvl l-oentene with a selectivity of 99 molar per cent The reaction takes place around 200 at 20.10 Pa. 2-metbyl 1-pentcnc is the starting material for the synthesis of isoprene, in which it is hrst isomerized to 2-methyl 2-pentenes, and then cracked to produce isoprene. 

In the presence of acid catalysts (for example, phosphoric acid on support), propylene yields a mixture of the trimer and the tetramer. The UOP process is conducted in a 

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