Direct CO₂ Transformation to Aliphatic Polycarbonates

Abstract

Reduction of CO2 emission is an important issue all over the world, and the development of effective transformation methods of CO2 into valuable chemicals is highly desirable. Among various potential products derived from CO2, polymers are one of the promising target chemicals in terms of the production amount and CO2 fixation to solid materials. Therefore, the direct synthesis of polycarbonates from CO2 has recently attracted much attention because polycarbonates including polycarbonate diols are useful engineering plastics and intermediates for polyurethanes. There are many reports on the synthesis of polycarbonates from CO2 and cyclic ethers such as epoxides and oxetanes, however, the reports on the synthesis from CO2 and diols are limited. In this review, we summarize the recent progress of direct polycarbonate synthesis from CO2 and diols and explain the potential and issues for industrialization based on the characteristics of the reaction systems.

Comparative Study between 2‐Furonitrile and 2‐Cyanopyridine as Dehydrants in Direct Synthesis of Dialkyl Carbonates from CO2 and Alcohols over Cerium Oxide Catalyst

“…Meanwhile, under the “stoichiometric” (alcohol/nitrile/CH 3 CN=50 : 25 : 100) and “alcohol‐excess” (100 : 25 : 100) conditions, the possible maximum amount of dialkyl carbonates is 25 mmol. Under these three conditions, we conducted the reactions using two different amounts of CeO 2 catalyst (0.17 g and 0.68 g), which and whose related materials have been reported by many research groups to exhibit good catalytic activity for non‐reductive conversion of CO 2 [4,21–27,34–57] . The results obtained with the smaller amount of CeO 2 catalyst (0.17 g) are reflected by the reactivity of alcohols and nitrile dehydrants over the catalyst surfaces, and those with the larger amount of CeO 2 (0.68 g) provide the information about the saturation level of the product formation.…”

Enabling New Approaches: Recent Advances in Processing Aliphatic Polycarbonate‐Based Materials

“…Initially, aPCs were synthesized by following the same method as employed for aromatic polycarbonates viz. condensation of aliphatic diols with toxic phosgene gas [1,19] . The main drawback of this method is the use of highly toxic reagents and the high dispersity associated with the resulting polycarbonates [1] .…”

“…condensation of aliphatic diols with toxic phosgene gas. [1,19] The main drawback of this method is the use of highly toxic reagents and the high dispersity associated with the resulting polycarbonates. [1] This approach was slightly modified by doing a two-step melt reaction between aliphatic diols and dialkyl carbonate, which entails an initial condensation to form oligomers and a subsequent transesterification or carbonate metathesis in the presence of catalysts.…”

Rational Design of Heterogeneous Dual-Atom Catalysts for CO2 Electroreduction Reactions

“…As an alternative, CO 2 capture and utilization have received much attention, as CO 2 can be used to produce high-value chemicals via chemical transformation or electrocatalytic, , photocatalytic, , and photothermocatalytic processes. In this regard, CO 2 has been used as a C 1 building block to produce value-added chemicals (carbon monoxide, methanol, formic acid, formaldehyde, acetic acid, and acetaldehyde), high-energy-density fuels (methane, propane, and ethanol), and precursors for polymers such as ethylene and carbonate . Production of liquid electro-fuels (e-fuels) derived from CO 2 , to substitute fossil fuel is vital to reaching a net-zero carbon footprint.…”

“…In this regard, CO 2 has been used as a C 1 building block to produce value-added chemicals (carbon monoxide, methanol, formic acid, formaldehyde, acetic acid, and acetaldehyde), high-energy-density fuels (methane, propane, and ethanol), and precursors for polymers such as ethylene 8 and carbonate. 9 Production of liquid electro-fuels (e-fuels) derived from CO 2 , 10 to substitute fossil fuel is vital to reaching a net-zero carbon footprint. In addition, CO 2 can be used for the functionalization of organic compounds through photo-and electrocatalytic carboxylation reactions.…”