The author of 《Volume changes in the proton ionization of amines in water. 1. Morpholines and piperazines》 were Cabani, S.; Mollica, V.; Lepori, L.; Lobo, S. T.. And the article was published in Journal of Physical Chemistry in 1977. Electric Literature of C5H14Cl2N2 The author mentioned the following in the article:
Apparent molar volumes, Φv, at various concentrations in water at 25° of some cyclic bifunctional amines [morpholine, 4-methylmorpholine, piperazine, 1-methyl- and 1,4-dimethylpiperazine, 1,4-diazabicyclo[2.2.2]octane (triethylenediamine)] and their mono- and dihydrochlorides were determined The volume changes ΔV1° and ΔV2°, involved in the 1st and 2nd proton ionizations from the protonated amines, were calculated from the limiting partial molar volumes V̅2°. The volumes of ionization for the bifunctional cyclic amines were compared with those for the monofunctional amines ad the relationship between entropies and volumes of ionization was examined In the experiment, the researchers used 1-Methylpiperazine dihydrochloride(cas: 34352-59-5Electric Literature of C5H14Cl2N2)
1-Methylpiperazine dihydrochloride(cas: 34352-59-5) is used in the preparation of 2-(4-Methyl-1-piperazinylmethyl)acrylophenone(MPMAP), 1-methylpiperazine-1,4-diium tetrachloridozincate hemihydrate, 2-(4-Methyl-1-piperazinylmethyl)acrylophenone(MPMAP), an antimicrotubular drug..Electric Literature of C5H14Cl2N2
Referemce:
Piperazine – Wikipedia,
Piperazines – an overview | ScienceDirect Topics