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Development of efficient methods for CO 2 recovery from industrial waste gases etc. is extremely important in relation to both reutilization of CO 2 as carbon resources 1 and environmental issue concerned with the greenhouse effect. 2 One of the most commonly used processes for CO 2 recovery is chemically reversible CO 2 fixation by primary or secondary amines based on CO 2 fixation by amines at room temperature to give ammonium carbamates, and CO 2 release from ammonium carbamates upon heating. 3 Application of CO 2 fixation in functional polymers has been also examined, 4 for instance, copolymers of styrene bearing pendant amino groups fixed CO 2 under ambient conditions. 4b A more attractive process may be CO 2 fixation by tertiary amines giving zwitterion adducts that may provide a more easily handled fixation-release treatment, since these zwitterions could release CO 2 at reduced temperatures owing to their lability (primary-(secondary) amines; at >100°C). Furthermore, this process can provide zwitterions having a unique reactivity. However, detailed studies concerning CO 2 fixation by tertiary amines and its application to functional polymers have not been carried out. Here we report a new type of reversible CO 2 fixation by amidine derivatives and by polymers bearing an amidine moiety both in solution and solid state.In the course of the study of CO 2 fixation by tertiary amines, there has been one example of CO 2 fixation by 1,8-diazabicyclo[5.4.0]-undec-7-ene (DBU) to afford the zwitterion adduct. 5 Assuming the reasons why DBU can react with CO 2 are its high nucleophilicity and stabilization of the cation species by delocalization in the amidine moiety, we constructed the idea that amidine derivatives with higher nucleophilicity may provide a success of CO 2 fixation. N-Methyltetrahydropyrimidine (MTHP) containing an amidine structure was synthesized, 6 since it would have higher nucleophilicity due to decrease in the steric hindrance around the nitrogen atom of imine moiety. CO 2 fixation using MTHP was performed in N,N-dimethylformamide (DMF) at 25°C under atmospheric pressure. 7 Fixing efficiency (%, mmol of CO 2 /mmol of MTHP) was estimated from the weight increase in the reaction mixture. When CO 2 was bubbled into a DMF solution of MTHP, a white precipitate was formed immediately, and the weight increase in the reaction mixture ceased after 1 h to afford the corresponding zwitterion adduct (MTHP)CO 2 ) in quantitative fixing efficiency. On the other hand, DBU needed 100 h to fix CO 2 in 89% fixing efficiency, 8 thus, MTHP proved to be an excellent agent for CO 2 fixation. The IR spectrum of MTHP)CO 2 showed two absorption bands assignable to the CO 2 moiety at 1689 and 1389 cm -1 . The 1 H NMR spectrum of MTHP)CO 2 showed that the signal of the imine proton was shifted to lower field (0.57 ppm) compared with MTHP and the 13 C NMR spectrum showed a signal attributable to the carbonyl group at 161.3 ppm.Reversibility of CO 2 fixation by MTHP was examined ( Figure 1): The obtained zwitterion addu...

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Aliphatic polyurethanes could be obtained in high yield via a non‐isocyanate method based on the self‐polycondensation of dihydroxyurethanes obtained by the reaction of diamines and ethylene carbonate. The polycondensation under a N2 atmosphere yielded [6,2]polyurethane with a Mn value of 5300 in 87% yield. Two‐step polycondensation, consisting of the polycondensation under a N2 atmosphere followed by that under reduced pressure, was effective to improve the yield and the molecular weight up to 90% and 10,000, respectively. Although the second polycondensation step at 180 °C was accompanied by formation of urea groups, this side reaction was relatively suppressed at 150 °C. The resulting polyurethane having hydroxyl groups at both of the end groups was converted to polyurethane methacrylate via a reaction with glycidyl methacrylate, and the polyurethane methacrylate served as a crosslinker for radical polymerization of methyl acrylate. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2013