Synthesis of chiral propylene carbonate via asymmetric ring opening of racemic propylene oxide by carbon dioxide on immobilized cobalt salen catalyst

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• 作者：Da Young Jang ; Hyung Gyu Jang ; Gye Ryung Kim ; Geon-Joong Kim ; ^{kimgj@inha.ac.kr}
• 关键词：Chiral cobalt salen ; Epoxides ; Lewis acid ; Resolution
• 刊名：Catalysis Today
• 出版年：2012
• 期刊代码：13_09205861
• 类别：ce
• 出版时间：20 May, 2012
• 卷：185
• 期：1
• 页码：306-312
• 文件大小：1564 K

摘要

Chiral Co(salen) complexes bearing Co(BF₄)₂ salt could efficiently catalyze the ring opening reaction of terminal epoxide by carbon dioxide in the presence of catalytic amounts of ionic liquid. The high amount loading of ionic liquid C6-IL as a co-catalyst led to the decrease the ee%of propylene carbonate (PC), but the conversion of propylene oxide (PO) has increased with the added amount. The homogeneous salen catalyst could be immobilized easily on the acidic sites of supports by non-covalent bonding, and exhibited moderate activity for producing enantiomerically enriched cyclic carbonates. The optically pure cyclic carbonates can be obtained by the catalytic resolution process resulting from HKR of racemic (卤)PO in conjunction with CO₂ coupling, as one-pot reaction. The presence of water improved the optical purity of final product PC in that system. The heterogenized chiral salen catalyst has retained the high activity in the repeated use, and no severe extraction of salen complexes from the support was found by using a heterogenized IL.