Dear Catherine Esnaashari,

Calcium ions (based on operating conditions) can act as catalyst in transesterification reactions of PET/PC system. In a study by Al-Jabareen, A., Illescas, S., Maspoch and Santana O.O. (2010), titled "Effects of composition and transesterification catalysts on the physico-chemical and dynamic properties of PC/PET blends rich in PC", they report that degree of transesterification depends on the amount of PET and presence/type of catalyst. All blends without transesterification catalysts (Ca or Zn ions) exhibited a degree of transesterification that decreased by increasing the amount of PET in the blend.

However, Ca based catalysts are just intermediate in activity compared to the highly active titanium and samarium based ones...for the reaction in question.

Regards.