Pentene multiple reactions

A simple test to distinguish between 2-pentene and cyclopentane is to add a few drops of a red Br2 solution to the unknown liquid. The reddish color will disappear if the liquid is an alkene or alkyne, e.g., 2-pentene, due to the addition of Br2 to the multiple bond. No such addition reaction occurs between Br2 and cyclopentane. 

Only a few examples of the double germylation of C-C multiple bonds have been reported in the past decade. The catalytic reaction of a digermir-ane with acetylenes results in the formation of ring-expanded digermacyclo-pentenes [Eq. 21 )].63... 

Ion—molecule reactions in olefins, especially in those higher than ethylene, are characterized by their complexity due to multiple products from a given reactant and multiple reactants for a given product. Thus, even restricting ourselves to reactions of parent ions with parent molecules, at least five reactions in propene, eight reactions in 1-butene, and nineteen reactions in 1-pentene are observed. Occurrence of several primary fragment ions in ordinary electron impact and radiolysis systems makes the situation more complicated. 

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