Aliphatic and cycloaliphatic hydrocarbon resins

It has long been known that normally gaseous olefins can be converted to viscous liquid polymers by means of solid aluminum chloride or by other catalytic systems [9-18]. A well-known and widely used olefin feedstock for such oligomerization is a petroleum refinery butane- and butylene-containing stream, referred to as B-B stream.  

The primary products obtained from the oligomerization of a typical B-B stream are oligomers having molecular weights in the range of from about 900 to 

The products produced may be oligomers or high polymers [20,21]. Better known are isobutene copolymers with butenes [22], styrene [23], or cyclopenta-dienes [24]. 

The linear dimerization of butadiene has been effected with a NiBr,(PPh3)2 complex associated to sodium borohydride (NaBH4 Ni = 2 1) [34a]. In a mixture of ethanol-tetrahydrofuran (THF) at 100°C, 1,3-butadiene is dimerized to (E,E)l,3,6-octatriene in 95% or greater yield and with more than 99% selectivity. 

The polystyrene-supported analogue, (polystyrene-PPh2)3NiBr2, when treated with NaBH4, gave essentially the same results. In pure ethanol, the reaction failed, presumably due to the lack of swelling of the polymer. However, the supported catalyst collapsed after a while, corresponding to about 1500 mol butadiene converted in a batch operation. 

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