Historical Milestones in Hydrocarbon Chemistry

1825 — Michael Faraday isolates benzene from whale oil gas; early interest in hydrocarbons begins.

1828 — Friedrich Wöhler synthesizes urea from ammonium cyanate; begins the fall of "vital force" theory. Organic chemistry becomes a science.

1865 — August Kekulé proposes the hexagonal structure of benzene. His work on carbon tetravalency (1858) laid the foundation for understanding alkane and alkene structures.

1869 — Vladimir Markovnikov publishes his rule for addition of HX to unsymmetrical alkenes: H adds to the more hydrogenated carbon. A cornerstone of OC-02.

1912 — Paul Sabatier receives Nobel Prize for heterogeneous catalytic hydrogenation ($H_{2}$ over Ni), the basis for $H_{2}$ addition to alkenes and alkynes.

1930s — Morris Selig Kharasch discovers anti-Markovnikov addition of HBr in the presence of peroxides (Kharasch effect). Free radical mechanism established.

1952 — Herbert C. Brown (Nobel 1979) develops hydroboration; later, Lindlar develops Pd/$CaCO_{3}$ catalyst for selective alkyne reduction to cis-alkene.

1959 — Lindlar catalyst formally described: Pd on $CaCO_{3}$ poisoned with Pb(OAc)_{2} and quinoline for selective syn-hydrogenation of alkynes.

1953 — Criegee mechanism for ozonolysis established; the stepwise formation of ozonide followed by reductive/oxidative workup is confirmed.

1970s-present — Newman projections and conformational analysis (developed by Melvin Newman, 1952) become standard tools in teaching and understanding alkane conformational preferences.