Consider the highly toxic molecule -trichloro-2,2-di(p-chlorophenyl)ethane, commonly known as DDT. W — Haloalkanes and Haloarenes Chemistry Question
Question
Consider the highly toxic molecule $1,1,1$ -trichloro-2,2-di(p-chlorophenyl)ethane, commonly known as DDT. When subjected to intense heating with a strong base (like alcoholic KOH), it readily undergoes targeted dehydrohalogenation. Assuming complete exhaustive E2/E1cB elimination to form a fully stable, highly conjugated pi-system, exactly how many moles of $HCl$ are formally eliminated from exactly one mole of DDT?
💡 Solution & Explanation
The organic structure of DDT is $(p-ClC_6H_4)_2CH-CCl_3$. The $\beta$ -carbon has exactly one highly acidic, abstractable proton due to the massive inductive pull of the rings and chlorines. The adjacent $\alpha$ -carbon contains three heavy chlorine atoms. Upon treatment with base, the single $\beta$ -proton is rapidly abstracted, ultimately eliminating exactly one chlorine atom from the adjacent carbon to form a heavily stabilized central double bond: $(p-ClC_6H_4)_2C=CCl_2$ (forming the compound DDE). Because there are absolutely no more $\beta$ -hydrogens remaining anywhere in the structure to pair with the remaining two chlorines, the elimination instantly stops. Thus, exactly 1 mole of $HCl$ is eliminated.