Non-Toxic and Environmentally Friendly Titanium Complexes and Their Effects on epsilon-Caprolactone Polymerization


YILDIZ ARAS B. C. , KAYAN A.

CATALYSIS SURVEYS FROM ASIA, 2020 (SCI İndekslerine Giren Dergi) identifier identifier

Özet

The need for homogenous titanium compounds as catalysts has been increasing gradually due to their non-toxic properties and catalytic activities. In this article, titanium salicylate complexes 1-7 were produced by reaction of titanium(IV) isopropoxide with salicylic, 5-chlorosalicylic, 5-nitrosalicylic, 4-hydroxysalicylic, 3-methylsalicylic, 4-methylsalicylic, and 3,5-ditertbutylsalicylic acids with 1:2 mol ratio in isopropanol. These complexes 1-7 were structurally characterized using a variety of instrumental techniques such as high resolution mass spectrometry (HRMS), FTIR and NMR spectroscopies, elemental and thermogravimetric (TG) analysis. Also, complexes 1-7 were applied as catalysts in the ring-opening polymerization (ROP) of epsilon-caprolactone and were highly efficient catalysts. Polycaprolactone (PCL) was analyzed using NMR spectroscopy, differential scanning calorimetry (DSC), and gel permeation chromatography (GPC) techniques. In the ROP reactions of epsilon-CL monomer, the catalysts containing electron donating groups on salicylate ligands were more effective than the catalysts containing electron withdrawing groups.