Pyrazolidine

Pyrazolidine is a heterocyclic compound. It is a liquid that is stable in air, but it is hygroscopic.

Preparation
Pyrazolidine can be produced by cyclization of 1,3-dichloropropane or 1,3-dibromopropane with hydrazine:


 * $$\mathrm{Cl{-}(CH_2)_3{-}Cl\ +\ N_2H_4\ \xrightarrow {\Delta T}\ C_3H_8N_2\ +\ 2 HCl}$$
 * $$\mathrm{Br{-}(CH_2)_3{-}Br\ +\ N_2H_4\ \xrightarrow {\Delta T}\ C_3H_8N_2\ +\ 2 HBr}$$