Alternating copolymerization of epoxides with carbon dioxide or cyclic anhydrides using bimetallic nickel and cobalt catalysts: Preparation of hydrophilic nanofibers from functionalized polyesters

Stereoregular poly(propylene carbonate)s and poly(propylene succinate-block-carbonate)s were synthesized with new chiral salenCo(iii) catalysts carrying bulky substituents.

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Tertiary Amines Paired with Trialkyl Boranes: A Simple Organocatalyst for Fully Alternating Copolymerization of Carbon Dioxide and Propylene Oxide

10.26434/chemrxiv.12522788.v1 ◽

2020 ◽

Author(s):

Xing-Hong Zhang

Keyword(s):

Carbon Dioxide ◽

Small Molecules ◽

Propylene Oxide ◽

Average Molecular Weight ◽

Tertiary Amines ◽

Carbon Dioxide Co2 ◽

Poly Propylene ◽

Alternating Copolymerization ◽

Completely Alternating ◽

Huge Challenge

Metal-free synthesis of fully alternating polycarbonates from carbon dioxide (CO2) and epoxides is highly desired but a huge challenge. Here, we disclose the combination of tertiary amines with trialkyl boranes for completely alternating copolymerization of CO2 with epoxides. Triethylamine (TEA) pairing with triethyl borane (TEB), the simplest catalyst for the copolymerization of CO2 and propylene oxide (PO), afforded fully alternating poly(propylene carbonate) (PPC) with a turnover frequency (TOF) of 54 h-1 at 60 oC. Remarkably, diamine such as, N,N,N',N'-tetraethylethylenediamine (TEED) and triamine such as N,N,N',N'',N''-pentamethyldiethylene triamine (PMDETA) pairing with TEB exhibited improved the copolymer selectivity of up to 99%. Supplementally, the effect of trialkylborane structure on the copolymerization were also investigated. Moreover, PPCs prepared from these tertiary amines/ trialkyl boranes Lewis pairs showed the head-to-tail diad content of around 80%. The number-average molecular weight of PPC was up to 56.0 kg/mol with narrow distribution (Đ =1.16) and could be easily adjusted by simply varying the feeding ratios. The 1H NMR spectra and MALDI-TOF-MS spectra suggest that both tertiary amine-activating CO2 and TEB-masked end anions cooperatively promote the fully alternating CO2/epoxide copolymerization. This work provides an organocatalytic platform for well-defined CO2/epoxide copolymers using simple small molecules with high atomic utilization.<br>

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Alternating Copolymerization of Carbon Dioxide with Cyclohexene Oxide Catalyzed by a Novel Catalyst

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.549.445 ◽

2012 ◽

Vol 549 ◽

pp. 445-448

Author(s):

Li Dan Fan ◽

Gang Qin ◽

Xin Xin Cao ◽

Shao Kui Cao

Keyword(s):

Carbon Dioxide ◽

Catalytic Activity ◽

Reaction Time ◽

Zinc Complex ◽

Cyclohexene Oxide ◽

Novel Catalyst ◽

Alternating Copolymerization

A novel catalyst for the copolymerization of CO2 and cyclohexene oxide(CHO) was prepared by using BTE and ZnCl2. The zinc complex showed catalytic activity for the copolymerization. The obtained copolymer was characterized by IR and NMR. Effect of reaction time on copolymerization was investigated.

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