Low-Temperature Methanolysis of Polycarbonate over Solid Base Sodium Aluminate

Philip Anggo Krisbiantoro; Miyu Sato; Tzu-Ming Lin; Yu-Chia Chang; Tzu-Yun Peng; Yun-Chih Wu; Weisheng Liao; Yuichi Kamiya; Ryoichi Otomo; Kevin C-W Wu

doi:10.1021/acs.langmuir.3c03799

Low-Temperature Methanolysis of Polycarbonate over Solid Base Sodium Aluminate

Langmuir. 2024 Mar 12;40(10):5338-5347. doi: 10.1021/acs.langmuir.3c03799. Epub 2024 Feb 26.

Authors

Philip Anggo Krisbiantoro^{1

2

3}, Miyu Sato⁴, Tzu-Ming Lin³, Yu-Chia Chang³, Tzu-Yun Peng³, Yun-Chih Wu³, Weisheng Liao³, Yuichi Kamiya⁵, Ryoichi Otomo⁵, Kevin C-W Wu^{1

2

3

6

7}

Affiliations

¹ Molecular Science and Technology Program, Taiwan International Graduate Program, Academia Sinica, Taipei 11529, Taiwan.
² International Graduate Program of Molecular Science and Technology, National Taiwan University, Taipei 10617, Taiwan.
³ Department of Chemical Engineering, College of Engineering, National Taiwan University, Taipei 10617, Taiwan.
⁴ Graduate School of Environmental Science, Hokkaido University, Nishi 5, Kita 10, Kita-ku, Sapporo 060-0810, Japan.
⁵ Faculty of Environmental Earth Science, Hokkaido University, Nishi 5, Kita 10, Kita-ku, Sapporo 060-0810, Japan.
⁶ Center of Atomic Initiative for New Materials, National Taiwan University, Taipei 10617, Taiwan.
⁷ Department of Chemical Engineering and Materials Science, Yuan Ze University, Chung-Li, Taoyuan 320, Taiwan.

Abstract

Herein, a low-cost and readily available sodium aluminate (NaAlO₂) was used as a solid base catalyst for the depolymerization of polycarbonate (PC) via methanolysis in the presence of tetrahydrofuran (THF) as a solvent. NaAlO₂ was highly active for the reaction, and the performance was comparable to that of soluble strong base SrO and much higher than those of MgO and CaO. By the reaction over the catalyst, a highly pure and crystalline bisphenol A (BPA) was obtained. Among tested organic solvents, THF was the best in aiding PC methanolysis over NaAlO₂ due to the polarity similar to PC according to Hansen solubility parameters (HSPs). At 60 °C, 98.1% PC conversion and 96.8% BPA yield were achieved within just 2 h. NaAlO₂ was reusable without any severe catalyst deactivation in at least four runs. The mechanistic study revealed that the reaction proceeded via the methoxide pathway, with THF aiding the dissolution of PC. The reaction over NaAlO₂ possessed a low apparent activation energy (E_a) of 75.1 kJ mol^-1, which is the lowest ever reported so far for the reaction over solid catalysts.