Fixing Carbon Dioxide Concurrently with Radical Polymerization for

Macromolecules 2008, 41, 9937-9939

Fixing Carbon Dioxide Concurrently with Radical Polymerization for Utilizing Carbon Dioxide by Low-Energy Cost †

†

,‡

Bungo Ochiai, Yugo Hatano, and Takeshi Endo*

Department of Polymer Science and Engineering, Faculty of Engineering, Yamagata UniVersity, 4-3-16 Jonan, Yonezawa, Yamagata 992-8510, Japan, and Molecular Engineering Institute, Kinki UniVersity, 11-6 Kayanomori, Iizuka, Fukuoka 814-0193, Japan ReceiVed August 31, 2008 ReVised Manuscript ReceiVed October 16, 2008 Introduction Carbon dioxide is an abundant nonpetroleum resource, and its efficient transformation into organic materials is one of the best solutions for saving the use of petroleum resources.1-6 However, typical reactions of carbon dioxide require high energy, for example, high temperature or high pressure, because of the stability of carbon dioxide. The reaction of carbon dioxide and epoxides that afford five-membered cyclic carbonates proceeds smoothly under relatively mild conditions.7-14 Although this reaction is effective in the preparation of monomers or in polymer reactions, these reactions are not suitable enough to save the energy to transform carbon dioxide by the multiple steps required.15-30 For example, the most-examined polymers bearing five-membered cyclic carbonate are polymethacrylates prepared from two-step methods: radical polymerization of a methacrylate bearing cyclic carbonate moieties (DOMA) prepared from the reactions of carbon dioxide and glycidyl methacrylate (GMA) and reactions of carbon dioxide and polyGMA obtained by radical polymerizations. In addition to the two steps, including the required purification processes, these reactions are time-consuming (total time >10 h). Accordingly, we attempted a one-step reaction consisting of radical polymerization and paralleled carbon dioxide fixation. Results and Discussion Radical Polymerization of Glycidyl Methacrylate Paralleled with Carbon Dioxide Fixation. We employed LiBr for this combined reaction because of its high activity in N-methyl pyrrolidinone (NMP).8 The radical polymerization of GMA was conducted under a carbon dioxide atmosphere (1 atm) in the presence of LiBr and 2,2-azobisisobutyronitrile (AIBN) (3.0 mol % with respect to GMA) in NMP, N,N-dimethyl formamide (DMF), dimethyl sulfoxide (DMSO), and 1,4dioxane (DOX) (Table 1, runs 1-4). Polar solvents, especially amides, were effective for higher efficiency of the transformation into the carbonate group in a similar manner with the reaction of polyGMA with carbon dioxide.16,31 The almost quantitative carbon dioxide incorporation and the quantitative yield within 5 h at 80 °C (run 1) are significantly advantageous over the reported polymer reaction of polyGMA with carbon dioxide * Corresponding author. E-mail: [email protected]. Tel/ Fax: +81-948-22-7210. † Yamagata University. ‡ Kinki University.

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Table 1. Radical Polymerization of GMA Paralleled with Carbon

Dioxide Fixationa,b

copolymer temp LiBr conv. of composition yield c run (°C) initiator (mol %) solvent CdC (%)e (x/y)c,d 1 2 3 4 5 6 7 8 9 10 11

80 80 80 80 50 60 70 80 80 80 90

AIBN AIBN AIBN AIBN AIBN AIBN AIBN AIBN AIBN BPO BPO

3 3 3 3 3 3 3 0.5 5 3 3

NMP DMF DMSO DOX NMP NMP NMP NMP NMP NMP NMP