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Solutions to Problems 47 C-H bonds overlapping with the radical p orbital, and one with a bond participating instead of a C-H: CH₃ H H and H2C CH₃ H H H (b) In naming these, remember that the radical carbon is always (just like the "point of attachment" carbon in alkyl groups). The parent name is based on the longest carbon chain beginning at C1, and all appendages are named as substituents: CH₃-CH₂ CH₃-CH₂ 4 3 2 3 2 2-Ethylbutyl radical radical Primary, less stable Tertiary, more stable HC C CHCH₃ CH₃HC Hyperconjugation (Using C H bonds) (c) Left to right: 1,2-dimethylpropyl radical, secondary, intermediate in stability; radical, tertiary, most stable; 3-methylbutyl radical, primary, least stable. Hyperconjugation in the radical is the same as in [(b) above]; in picture, an H should replace one of the end CH₃ groups. 17. Work problems like this "mechanistically": Proceed via general reaction steps as you have previously seen/illustrated in the text until you reach stable molecules. Pyrolysis of propane starts as follows: (a) CH₃CH₂-CH₃ CH₃CH₂· + CH₃ bond cleavage Then there are three possible recombinations: (b) 2 CH₃· CH₃CH₃ (c) 2 CH₃CH₂CH₂CH₃ Ethane Butane (d) + CH₃CH₂CH₃ (Reverse of first step) Propane