Radical Chlorination

Chlorine has 4 possible carbons to bond to. When the products are analyzed, the most reactive hydrogens have the highest amound of isomers, and leave more easily. The 1,3-dichlorobutane isomer was the most common, forming almost 4 times as fast as the 1,4-dichlorobutane (C4 farthest from chlorine and least influenced by its electronegativity). The next most reactive hydrogens were located on carbon number 2, followed by those on carbon number 4, and then those on carbon number 1. Chlorine has a strong pull on electrons, so it increases the strength of the carbon-hydrogen bonds close to it. If bond strength increases, then relative reactivity decreases. This would have the most effect on the carbon-hydrogen bonds of carbon number 1 and carbon number 2 because they are closer to chlorine. Chlorine would have the slightest influence on carbon number 3 and carbon number 4 because they are farther from chlorine. Chlorine also causes steric issues with the structure of 1,1-dichlorobutane. Because there is a chlorine on carbon number 1, the development of a second carbon-chlorine bond is unlikely, which is represented in the GC as a low percentage. Free-radicals are most stable when the unpaired electron is accompanied by more than one alkyl group. The more alkyl groups attached to the carbon where the lone electron is, the more stable that free-radical. When the free-radical forms at carbon-3, it is located between two alkyl groups. When it forms on carbon number 4, it is only near one alkyl group. Therefore, the lone electron is found most frequently on carbon number 3 because it is more stable.