Carbon dioxide copolymerization

Keywords Carbon dioxide Copolymerization Oxetanes Polycarbonates Schiff-base ligands... 

Kim, S. M. Kim, C.-S. Ha, D.-W. Park, Synthesis and cyclohexene oxide/carbon dioxide copolymerizations of zinc acetate complexes bearing bidentate pyridine-alkoxide ligands, Macro-molec. Rapid Commun. 25 (2004) 888. 

Copolymerization of carbon dioxide possibly also belongs to this class of polymerizations. Carbon dioxide copolymerizes with epoxides to polyanhydrides, with aziridines to polyurethanes, and with vinyl ethers to poly-ketoethers, i.e.. 

Azelaic, sebacic, dodecanedioic, and brassyhc acids may be used in copolyetheresteramides (111). Two patents describe additional apphcations for the C-9—C-40 diacids for the preparation of polyester carbonates (112), and the copolymerization of epoxides and carbon dioxide by reaction of either glutaric or adipic acids with zinc oxide (113). 

An alternative method for generating enriched 1,2-diols from meso-epoxides consists of asymmetric copolymerization with carbon dioxide. Nozaki demonstrated that a zinc complex formed in situ from diethylzinc and diphenylprolinol catalyzed the copolymerization with cyclohexene oxide in high yield. Alkaline hydrolysis of the isotactic polymer then liberated the trans diol in 94% yield and 70% ee (Scheme 7.20) [40]. Coates later found that other zinc complexes such as 12 are also effective in forming isotactic polymers [41-42]. 

Copolymers of carbon monoxide, carbon dioxide, sulfur dioxide or carbon disulfide are frequently formed in combination with oxiranes, thiiranes or aziridines. Copolymerization of carbon monoxide and ethylenimine was carried out under radiation and the formation of 3-nylon was observed238. ... 

Incorporation of carbon dioxide as a reactive comonomer has been studied by several groups. Inoue et al. were the first to succeed in preparing high molecular weight polycarbonates by the copolymerization of carbon dioxide and propylene oxide241,242 ... 

Another interesting field is the utilization of unused resources such as carbon monoxide, carbon dioxide, etc. Development of useful copolymers is expected to come by applying the modern techniques of polymer chemistry. Ring-opening copolymerization should be one of the most likely methods for this purpose. 

In our previous work [8], we rqjorted the synthesis of (2-oxo-l,3-dioxolan-4-yl)methacrylate (DOMA) finrn carbon dioxide and glycidyl methacrylate (GMA) using quaternary salt catalysts. In the present work, we studied the catalytic pra rmance of alkyhnethyl imidazolium salt ionic liquid in the synthesis of polycarbonate from the copolyraerization of CO2 with GMA. The influences of copolymerization variable like catalyst structure and reaction tenperature on the conversion of GMA and the yield of the polycarbonate have been discussed. 

Equations 1 to 3 show some of fixation reactions of carbon dioxide. Equations la and lb present coupling reactions of CO2 with diene, triene, and alkyne affording lactone and similar molecules [2], in a process catalyzed by low valent transition metal compounds such as nickel(O) and palladium(O) complexes. Another interesting CO2 fixation reaction is copolymerization of CO2 and epoxide yielding polycarbonate (equation 2). This reaction is catalyzed by aluminum porphyrin and zinc diphenoxide [3],... 

Furthermore, size-exclusion chromatography (SEC) analyses generally reveal a bimodal distribution of molecular weights of the copolymers. Concomitantly, MALDI-ToF mass spectral measurements exhibit two sets of peaks corresponding to copolymer end groups of -OH and -X. For example, utilizing a (salen)CrCl/bis (triphenylphosphme)iminium chloride ([PPNjCl) catalyst for the copolymerization of cyclohexene oxide and carbon dioxide, the two copolymers illustrated in Fig. 6 were observed [26]. 

Lu and coworkers have synthesized a related bifunctional cobalt(lll) salen catalyst similar to that seen in Fig. 11 that contains an attached quaternary ammonium salt (Fig. 13) [36]. This catalyst was found to be very effective at copolymerizing propylene oxide and CO2. For example, in a reaction carried out at 90°C and 2.5 MPa pressure, a high molecular weight poly(propylene carbonate) = 59,000 and PDI = 1.22) was obtained with only 6% propylene carbonate byproduct. For a polymerization process performed under these reaction conditions for 0.5 h, a TOF (turnover frequency) of 5,160 h was reported. For comparative purposes, the best TOF observed for a binary catalyst system of (salen)CoX (where X is 2,4-dinitrophenolate) onium salt or base for the copolymerization of propylene oxide and CO2 at 25°C was 400-500 h for a process performed at 1.5 MPa pressure [21, 37]. On the other hand, employing catalysts of the type shown in Fig. 12, TOFs as high as 13,000 h with >99% selectivity for copolymers withMn 170,000 were obtained at 75°C and 2.0 MPa pressure [35]. The cobalt catalyst in Fig. 13 has also been shown to be effective for selective copolymer formation from styrene oxide and carbon dioxide [38]. 

Fig. 13 Bifunctional (saien) CoX catalyst for the copolymerization of propylene oxide and carbon dioxide...

We have utilized somewhat less-effective optional approaches to copolymer purification with attendant catalyst recovery. One of these methods involved the replacement of the f-butyl substituents on the 5-position of the phenolate ligands with poly(isobutylene) (PIB) groups, as illustrated in Fig. 14 [39]. Importantly, this chromium(III) catalyst exhibited nearly identical activity as its 3,5-di-t-butyl analog for the copolymerization of cyclohexene oxide and carbon dioxide. The PIB substituents on the (salen)CrCl catalysts provide high solubility in heptanes once the copolymer is separated from the metal center by a weak acid. 

As alluded to earlier, an important advancement in catalyst design for the copolymerization of epoxides and carbon dioxide involves the use of Schiff base metal complexes where the ligand is in a cis configuration, as depicted in Fig. 9. For example, Chen and coworkers have recently reported a (salen)Co... 

Inoue S, Koinuma H, Tsumta T (1969) Copolymerization of carbon dioxide and epoxide. J Polym Sci Part B Polym Lett 7 287-292... 

Chisholm MH, Navarro-Llobet D (2002) Poly(propylene carbonate). 1. More about poly (propylene carbonate) formed from the copolymerization of propylene oxide and carbon dioxide employing a zinc glutarate catalyst. Macromolecules 35(6) 6494—6504... 

Wang JT, Zhu Q, Lu XL, Meng YZ (1995) ZnGA-MMT catalyzed the copolymerization of carbon dioxide with propylene oxide. Eur Polym J 41 1108-1114... 

Shi L, Lu X-B, Zhang R, Peng X-J, Zhang C-Q, Li J-E, Peng X-M (2006) Asymmetric alternating copolymerization and terpolymerization of epoxides with carbon dioxide at mild conditions. Macromolecules 39 5679-5685... 

Tan C-S, Chang C-F, Hsu T-J (2002) Copolymerization of carbon dioxide, propylene oxide and cyclohexene oxide by a yttrium-metal coordination catalyst system. In CO2 conversion and utilization. ACS Symp Ser 809 102-111... 

Hsu T, Tan C (2002) Block copolymerization of carbon dioxide with cyclohexene oxide and 4-vinyl-1-cyclohexene-1,2-epoxide in based poly(propylene carbonate) by yttrium-metal... 

Darensbourg DJ, Wildeson JR, Yarbrough JC, Reibenspies JH (2000) Bis 2,6-difluorophen-oxide dimeric complexes of zinc and cadmium and their phosphine adducts lessons learned relative to carbon dioxide/cyclohexene oxide alternating copolymerization processes catalyzed by zinc phenoxides. J Am Chem Soc 122 12487-12496... 

Darensbourg DJ, Holtcamp MW (1995) Catalytic activity of zinc(II) phenoxides which possess readily accessible coordination sites. Copolymerization and terpolymerization of epoxides and carbon dioxide. Macromolecules 28 7577-7579... 

Robertson NJ, Qin Z, Dallinger GC, Lobkovsky EB, Lee S, Coates GW (2006) Two-dimensional double metal cyanide complexes highly active catalysts for the homopolymerization of propylene oxide and copolymerization of propylene oxide and carbon dioxide. Dalton Trans 5390-5395... 

Wang JT, Shu D, Xiao M, Meng YZ (2006) Copolymerization of carbon dioxide and propylene oxide using zinc adipate as catalyst. J Appl Polym Sci 99 200-206... 

---