自秋不特大对 花中院。 Sec 2 Preparation of alkynes Synthesis of Acetylene OThe electrophilic addition of bromine to form a vicinal dibromide then dehydrohalogenation with strong base. o Alkylation of terminal alkynes. NaNH2 heat R一C=C一R +2H8 Fig 2.Synthesis of an allkyne from an alkene. Sec 2 Preparation of alkynes ◼Synthesis of Acetylene ⚫The electrophilic addition of bromine to form a vicinal dibromide then dehydrohalogenation with strong base. ⚫ Alkylation of terminal alkynes