8.4 Physical properties of alkenes and alkynes 8.5 Hydrogenation of alkenes Ni Pd or pt H2C=CH2 H -Ch3 CH 25°C H2c=CH—cH3+H2 CH3 CH2CH an addition reaction(加成反应) Reduction(还原反应) Catalytic hydrogenation(催化氢化)8.4 Physical properties of alkenes and alkynes 8.5 Hydrogenation of alkenes H2 C CH2 + H2 CH3 CH3 H2 C CH CH3 + H2 CH3 CH2 CH3 Ni, Pd or Pt 25 o C an addition reaction（ 加 成 反 应 ） Reduction (还 原 反 应 ） Catalytic hydrogenation (催 化 氢 化 ）