Types of hydrohalogenation reactions and catalysts

The addition of hydrogen halides to unsaturated organic compounds is called here hydrohalogenation in order to stress that it is the reverse reaction to dehydrohalogenation. Two types of the hydrohalogenation reaction have to be considered, the addition to a carbon carbon triple bond 

For both reactions, low temperatures and elevated pressures are favourable from the point of view of equilibria but high conversons of acetylene can be obtained even at atmospheric pressure and around 150°C. 

---