From Impossible to Possible: Atom‐Economic Polymerization of Low Strain Five‐Membered Carbonates

Abstract

The direct ring-opening polymerization (ROP) of propylene carbonate (PC) only affords oligomers with substantial unidentified by-products, which hinders the efficient utilization of PC. Through detailed studies, for the first time, a careful mechanism involving the in situ release of propylene oxide (PO) from PC decarboxylation is proposed. Further, we report a novel strategy of copolymerization of PC/cyclic anhydrides via in situ capture of the formed intermediates. Results show that PC is successfully transformed into polyesters. Especially for the ring-opening alternating copolymerization (ROAC) of PC/phthalic anhydride (PA), a variety of advantages are manifold: i) slowrelease of PO ensuring a perfectly alternating structure; ii) quantitative and fast transformation of PC; iii) visualization of polymerization process by a CO 2 pressure gauge. Of importance, through tandem polymerizations, PC is fully transformed into polyesters and polycarbonates concurrently, thus achieving PC utilization with a high atom-economy.

Utilization of CO2-Available Organocatalysts for Reactions with Industrially Important Epoxides

“…Carbon dioxide capture and utilization (CCU technologies) has been recognized as a possible and cost-effective way to reduce worldwide greenhouse gas emissions [1][2][3][4][5][6][7][8][9][10]. The use of CO 2 as a raw material in chemical synthesis is a research area of great scientific, economic and ecological interest [1][2][3][4][5][6][7][8][9][10][11][12][13][14]. The abundance and benignity of carbon dioxide, which is cheap, nontoxic and nonflammable, makes it a very attractive low-cost C1-synthon in organic chemistry.…”

“…The epoxides available for carbonation can be classified according to their bound substituents as terminal epoxides (containing at least one unsubstituted CH2 group in the oxirane ring) and internal epoxides (containing substituents on both carbon atoms of the oxirane ring, Figure 1). The reaction conditions for the efficient carbonation of epoxides differ significantly, utilizing terminal (for example, glycidyl derivatives such as epichlorohydrin or glycidol and corresponding glycidyl ethers) [1][2][3][5][6][7][8][9][10][11][12][13][14]) or sterically, much more hindered internal epoxides (for example, epoxidized fatty acids and their derivatives [4,[8][9][10][11][12][13][14]). From the sustainability point of view, bio-based epoxides ideally serve as suitable reactants for the production of cyclic carbonates utilizing waste CO2.…”

“…Cyclic carbonates are generally stable liquids, which enables the long-term sequestration of CO 2 , especially when cyclic carbonates are subsequently used for polymerization. Although the production of cyclic carbonates from CO 2 and epoxides has been industrialized since 1958 and uses inexpensive catalysts such as KI, the current production processes still suffer from major disadvantages, such as high reaction temperatures (180-200 • C), high pressure (5-8 MPa) and stoichiometric amounts of activating reagents [13,14].…”

“…Cyclic carbonates are used for polymer production, as electrolytes in lithium-ion batteries, polar aprotic (ethylene or propylene carbonate) or protic solvents (glycerol carbonate, etc.) and as chemical intermediates in organic synthesis [1][2][3][4][5][6][7][8][9][10][11][12][13][14] (Scheme 3).…”

One‐pot sequence‐selective synthesis of polylactone‐containing block terpolymers based on renewable terpenoid‐derived monomer and a simple organocatalyst

“…Among terpenoid‐derived monomers, camphoric anhydride (CA) is a promising candidate because of the cheap price of the raw material and simple producing procedure. Ring‐opening alternating copolymerization (ROAC) of CA and epoxide has been realized by tailor‐made organometallic catalysts 10–12 . However, the use of toxic metal and the complicated synthesis process for organometallics are inconsistent with requirements of green and sustainable chemistry.…”