Highly Active SO₄ ²⁻/xTiO₂-ZrO₂ Catalysts for the Esterification Between Terephthalic Acid and 1,3-Propanediol

• Published in: Catalysis letters 2009-08, Vol.131 (1-2), p.305-311
• Main Authors: Liu, Jian, Bian, Shu Guang, Xiao, Min, Wang, Shuan Jin, Meng, Yue Zhong
• Format: Article
• Language: English
• Subjects: Ammonia; Catalysis; Catalysts; Chemical synthesis; Electron microscopes; Esterification; Infrared radiation; Polyesters; Reflectance; Spinning (materials); Terephthalate; Terephthalic acid; X-ray diffraction; Zirconium dioxide
• ISSN: 1011-372X; 1572-879X
• DOI: 10.1007/s10562-009-9897-y

Poly (trimethylene terephthalate) (PTT) is considered as one of the excellent fiber materials in the twenty-first century. It was synthesized as early as in 1940s, but up to now, it is rather difficult to obtain the PTT with high molecular weight suitable for spinning, due to the absence of highly active catalysts. In this work, two series of catalysts, i.e., xTiO₂-ZrO₂ (x = 6, 8, 10, 15) and SO₄ ²⁻/xTiO₂-ZrO₂ (x = 6, 8, 10, 15) were prepared, and used for the esterification of terephthalic acid (TPA) and 1,3-Propanediol (PDO). The synthesized catalysts were fully characterized by scanning electron microscope (SEM), infrared diffusion reflectance spectrum (IDRS), X-ray diffraction (XRD) and NH₃-temperature programmed desorption (NH₃-TPD) techniques. Based on the difference in acidities between xTiO₂-ZrO₂ and SO₄ ²⁻/xTiO₂-ZrO₂ as indicated by characteristic results of IDRS and NH₃-TPD, SO₄ ²⁻/xTiO₂-ZrO₂ have more Brønsted acid sites on their surfaces than xTiO₂-ZrO₂, as a result, SO₄ ²⁻/xTiO₂-ZrO₂ had high activities for the esterification of TPA and PDO.