On thermal behaviour of DMC catalysts for ring opening polymerization of epoxides

• The new thermoanalytical data on the DMC catalysts constitution were obtained.
• The stepwise liberation of the DMC complex organic ligands was observed.
• At least three bonding states of DMC complex organic ligand were detected.
• The decomposition of tert-butanol ligand without an evaporation was found.
• All the ligands were liberated below the DMC catalyst working temperature range.

The thermoanalytical studies of two types of the double metal cyanide catalysts were carried out.The identity of the catalysts was characterized by an elemental analysis and FTIR. The thermoanalytical examinations performed with the use of TG-DSC, EGA-FTIR, EGA-MS shed new light on views of the bonding of the ligands in the DMC. The chemical justification of the processes responsible for the TG/DSC steps was proposed. Several organic ligand complexing states were found in both types of catalysts. The ligand-DMC bondings were decomposing stepwise in relatively low temperature ranges, which could suggest their negligible role at catalytic reaction being performed usually at higher temperatures.The stoichiometric quantitative correlation between the values of TG steps responsible for the ligands evolution, and the concentration of total carbon, nitrogen and cobalt was found.The relationship was used as a base for the quantitative method of characterization of the DMC catalysts.

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