Identification and Quantification of Intracoordination Water in Insoluble Pectinates Cu~(~(2+)) and Pb~(~(2+))

摘要

By derivatography in insoluble pectins Cu~(2+) (PCu~(2+)) and Pb~(2+) (PPb~(2+)), the presence of "a high-temperature component" (150°C - 165°C) is established. During potentiometric alkalimetric titration of PCu~(2+) and PPb~(2+), endpoints are established at pH accordingly 4.87 and 4.95, proving acid properties of PM. Obtained data show the presence of water in the internal sphere of PM. Considering the loss of this water and the known ratio of metal cations and monomers of pectin (L~-), the simplest formulas of pectins are established: Cu(L~-)2(H2O)2, Pb(L~-)2(H2O)4.