41. The ethylene ligands are labile and readily displaced even by other alkenes . 42. To do so, the best-known methods are hydrogenation of alkenes : 43. Almost all industrial processes involving alkene -derived polymers rely on organometallic catalysts. 44. The polymerization reaction of alkenes occurs similarly to the reactions in metallocene catalysts: 45. Benzene undergoes substitution reactions, rather than addition reactions as typical for alkenes . 46. Alkenes and aromatics were held to very low levels.47. Ordinary alkenes are not susceptible to a nucleophilic attack ( apolar bond ). 48. Steam cracking is used in the petroleum industry to produce the lighter alkenes . 49. In addition, the alkene to alkane ratio increases. 50. The most commonly used dipolarophiles are alkenes and alkynes.
