Poly(4‐vinylimidazolium)s/Diazabicyclo[5.4.0]undec‐7‐ene/Zinc(II) Bromide‐Catalyzed Cycloaddition of Carbon Dioxide to Epoxides

Abstract

Poly(4-vinylimidazolium)s, derived from the self-immobilization of 4-vinylimidazoliums, with diazabicycloA C H T U N G T R E N N U N G [5.4.0]undec-7-ene (DBU) and zinc bromide (ZnBr 2 ) are used as a highly efficient catalyst for the chemical fixation of carbon dioxide. This catalytic system has been applied for the preparation of cyclic carbonates from terminal epoxides and carbon dioxide. Many functional groups, including chloro, vinyl, ether, and hydroxy groups are well tolerated in the reactions. Moreover, the catalytic system was found to catalyze the conversion of more sterically congested epoxides which are generally considered to be challenging substrates for fabricating the cyclic organic carbonates. In addition, the disubstituted epoxides are found to react with retention of configuration. The polymer precatalyst is easily recovered and reused. A plausible reaction mechanism is proposed.

Synthesis of Cyclic Carbonates Catalysed by Chromium and Aluminium Salphen Complexes

“…In this case, the reaction temperature was raised to 90 °C as the epoxide is a solid at 50 °C. There are very few examples of the synthesis of 12 e via catalytic addition of carbon dioxide to stilbene oxide, making complex 6 a rare example of a catalyst able to transform bulky epoxide 11 e into cyclic carbonate 12 e in high yield. Complex 6 was also active with other sterically hindered epoxides, 11 f and 11 g , and provided cyclic carbonates 12 f and 12 g in good yields (Table , entries 9 and 10).…”

Advances in Organic and Organic-Inorganic Hybrid Polymeric Supports for Catalytic Applications

“…The pre-catalyst 39 was recovered and reused without loss of performance over seven cycles. The material 39 showed high catalytic activity even in the tandem formation of γ-butyrolactone from benzaldehyde and methyl acrylate [31]. benzyl as by-product in various yields (less than 7%).…”

“…The pre-catalyst 39 was recovered and reused without loss of performance over seven cycles. The material 39 showed high catalytic activity even in the tandem formation of γ-butyrolactone from benzaldehyde and methyl acrylate [31]. In 2015 Wang and Chen reported the first highly efficient and fully recyclable heterogeneous catalyst systems for self-coupling of furaldehydes, particularly furfural and 5-hydroxymethylfurfural [34].…”

“…In 2014, Seo and Chung reported the first successfully recyclable catalytic system for benzoin condensation [30]. Particularly, poly(4-vinylimidazolium) iodide [31] 39 was prepared by polymerization of 4-vinylimidazolium 38, synthesized starting from histamine. Subsequently, the polymer was tested as an organic pre-catalyst in benzoin condensations (Scheme 17).…”

Efficient chemical fixation of CO2 into cyclic carbonates using poly(4‐vinylpyridine) supported iodine as an eco‐friendly and reusable heterogeneous catalyst

“…In view on the importance of the chemical fixation of CO 2 , a broad range of homogeneous and heterogeneous catalysts including organic bases, ionic liquids, supported catalysts, organic copolymers, and carbon materials have been investigated for the cycloaddition of CO 2 with epoxides . Among these materials, different polymer‐supported catalysts with desirable selectivity have been developed which are superior to homogeneous catalysts in terms of catalyst stability and separation of catalyst . However, some of the catalysts and protocols have drawbacks such as the use of a high temperature and CO 2 pressure, metallic ions, high‐cost procedures for product separation and/or catalyst synthesis, low activity, poor stability, unsatisfactory reusability, and need a long reaction time.…”