CHAPTER 6 REACTIONS OF ALKENES: ADDITION REACTIONS ow that were familiar with the structure and preparation of alkenes, let's look at their chemical reactions. The characteristic reaction of alkenes is addition to the double bond according to the general equation A The range of compounds represented as a-B in this equation is quite large, and their variety offers a wealth of opportunity for converting alkenes to a number of other func- tional group types Alkenes are commonly described as unsaturated hydrocarbons because they have the capacity to react with substances which add to them. Alkanes, on the other hand, are said to be saturated hydrocarbons and are incapable of undergoing addition reactions 6.1 HYDROGENATION OF ALKENES The relationship between reactants and products in addition reactions can be illustrated y the hydrogenation of alkenes to yield alkanes. Hydrogenation is the addition of H to a multiple bond. An example is the reaction of hydrogen with ethylene to form ethane H HH +H一H鸟哑 H△H=-136kJ H H (-32.6kcal) HH Ethylene Hydrogen Ethane 208 Back Forward Main MenuToc Study Guide ToC Student o MHHE Website208 CHAPTER 6 REACTIONS OF ALKENES: ADDITION REACTIONS Now that we’re familiar with the structure and preparation of alkenes, let’s look at their chemical reactions. The characteristic reaction of alkenes is addition to the double bond according to the general equation: The range of compounds represented as A±B in this equation is quite large, and their variety offers a wealth of opportunity for converting alkenes to a number of other func￾tional group types. Alkenes are commonly described as unsaturated hydrocarbons because they have the capacity to react with substances which add to them. Alkanes, on the other hand, are said to be saturated hydrocarbons and are incapable of undergoing addition reactions. 6.1 HYDROGENATION OF ALKENES The relationship between reactants and products in addition reactions can be illustrated by the hydrogenation of alkenes to yield alkanes. Hydrogenation is the addition of H2 to a multiple bond. An example is the reaction of hydrogen with ethylene to form ethane. Pt, Pd, Ni, or Rh H° 136 kJ (32.6 kcal) H H H H H C C H   Ethane H H Hydrogen C H H H H C Ethylene  A B C  C A C C B Back Forward Main Menu TOC Study Guide TOC Student OLC MHHE Website