Pentyne

The pentynes ​​form a group of unsaturated aliphatic hydrocarbons with the general empirical formula C5H8 and a C- C triple bond in chemistry. They belong to the most alkynes.

There are three isomers:

All three isomers are virtually insoluble under normal conditions volatile, flammable liquids and in water. The isomers are highly reactive due to their C -C triple bond like most alkynes and can, for example, readily polymerize or undergo addition reactions.

Production and recovery

In the preparation of pentynes ​​can be expected from the corresponding alkene compounds, which are converted initially by addition of bromine to the corresponding vicinal dibromides. Dehydrohalogenation under basic conditions leads to the corresponding Pentinen. For the synthesis of 1- pentyne is assumed from the 1- pentene. Dibromide as an intermediate is dehydrohalogenated in the presence of potassium carbonate at elevated temperatures. Similarly, the preparation of 2 - pentyne, where the dehydrohalogenation is carried out in an alcoholic potassium hydroxide solution is possible. The synthesis of 3 -methyl -1-butyne starts from 3-methyl -1-butene, which is first brominated at -60 ° C. The resulting dibromide is dehydrohalogenated means of sodium amide in liquid ammonia.