自秋精达对 视中院 Sec 2 Preparation of alkynes Synthesis of Acetylene .The electrophilic addition of bromine to form a vicinal dibromide then dehydrohalogenation with strong base. o Alkylation of terminal alkynes. NaNH2 heat R-C=C一R+2HB/ 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