MoO₃/SO₄^2--TiO₂ catalyst for transesterification of dimethyl cabonate with phenol

CUI Li-ping(崔丽萍), LI Yan-jun(李彦君), LI Zhong(李忠), ZHAO Jun-fu(赵君芙)

(Key Laboratory of Coal Science and Technology of Ministry of Education and Shanxi Province,
(Taiyuan University of Technology), Taiyuan 030024, China)

Abstract:A new MoO₃/SO₄^2--TiO₂ catalyst was prepared by a conventional impregnation of SO₄^2-/TiO₂ as carrier with an aqueous solution of ammonium molybdate and used for the synthesis of transesterification of dimethyl carbonate (DMC) with phenol. A series of MoO₃/SO₄^2--TiO₂ catalysts with different MoO₃ loadings were investigated and characterized using X-ray diffraction (XRD), Fourier transform infrared spectrometer (FTIR)，NH₃-temperature programmed desorption (NH₃-TPD) and X-ray photoelectron spectroscopy (XPS). The results show that MoO₃ loading is related to the activity of transesterification reaction. With the increase of MoO₃ loading, the activity of transesterification reaction increases. The sulfur species in the catalyst have an influence on the molybdenum species, and lead to an increase in the electropositive of molybdenum, which promotes the catalytic activity of MoO₃/SO₄^2--TiO₂. Among the series of catalysts prepared, MoO₃/SO₄^2--TiO₂ with 10% MoO₃ and 823 K calcinated is found to be the most active catalyst for transesterification reaction. Under the reaction conditions of 453 K and 12 h, the conversion of DMC is 30.5 %, and the yields of MPC and DPC reach 21.2 % and 8.7 %, respectively.

Key words:dimethyl carbonate; diphenyl carbonate; transesterification; MoO₃