Propylene oxide copolymerization

Cyriac A, Lee SH, Varghese JK, Park ES, Park JH, Lee BY (2010) Immortal C02/propylene oxide copolymerization precise control of molecular weight and architecture of various block copolymers. Macromolecules 43(18) 7398-7401... 

IR analysis indicated no substantial improvement in polymer to cyclic carbonate selectivity. The best result achieved was 2.3 in the case of 1,2-butylene oxide compared to 2.0 for propylene oxide copolymerization in dioxane (the only literature result for this catalyst). (134) The polymer produced (in the case of cyclohexene oxide) was of moderate molecular weight and highly polydisperse (N i = 13,3(X), Mw = 68,800, Mw/Mn = 5.2 using polystyrene standards). 

Eberhardt, R. Allmendinger, M. Zintl, M. TroU, C. Luinstra, G.A. Rieger, B. New Zinc Dicarboxylate Catalysts for the CO Propylene Oxide Copolymerization Reaction Activity Enhancement through Zn(II)-Ethylsutfinate Initiating Groups. Macro-mol. Chem. Phys. 2004, 205, 42 7. 

Other interesting perfluoro ether stmctures can be obtained by copolymerization of hexafluoroacetone with ethylene oxide, propylene oxide, and trimethylene oxide with subsequent fluorination to yield the following stmctures (67) ... 

Propylene oxide can be copolymerized with other epoxides, such as ethylene oxide (qv) (25,29,30) or tetrahydrofiiran (31,32) to produce copolymer polyols. Copolymerization with anhydrides (33) or CO2 (34) results in polyesters and polycarbonates (qv), respectively. 

Crystallinity is low the pendent allyl group contributes to the amorphous state of these polymers. Propylene oxide homopolymer itself has not been developed commercially because it cannot be cross-baked by current methods (18). The copolymerization of PO with unsaturated epoxide monomers gives vulcanizable products (19,20). In ECH—PO—AGE, poly(ptopylene oxide- o-epichlorohydrin- o-abyl glycidyl ether) [25213-15-4] (5), and PO—AGE, poly(propylene oxide-i o-abyl glycidyl ether) [25104-27-2] (6), the molar composition of PO ranges from approximately 65 to 90%. 

The only known instance of ring-opening polymerization with these compounds is also the only report on the successful polymerization of 2,5-dihydrofuran74 in which this compound was cationically copolymerized with epichlorhydrin (rx 0, r2 0), propylene oxide (r, 0, r2 0) and 3,3-bischloromethyl oxacyclobutane (/ ] 0, r2 = 1.6). It was shown that all the copolymers obtained possessed a certain degree of unsaturation which was attributed to the presence of open units from 2,5-dihydrofuran. Thus, for example the alternating copolymer with epichlorhydrin had the following structure (IR spectra, Cl content. C=C analysis) ... 

Extensive studies of stereoselective polymerization of epoxides were carried out by Tsuruta et al.21 s. Copolymerization of a racemic mixture of propylene oxide with a diethylzinc-methanol catalyst yielded a crystalline polymer, which was resolved into optically active polymers216 217. Asymmetric selective polymerization of d-propylene oxide from a racemic mixture occurs with asymmetric catalysts such as diethyzinc- (+) bomeol218. This reaction is explained by the asymmetric adsorption of monomers onto the enantiomorphic catalyst site219. Furukawa220 compared the selectivities of asymmetric catalysts composed of diethylzinc amino acid combinations and attributed the selectivity to the bulkiness of the substituents in the amino acid. With propylene sulfide, excellent asymmetric selective polymerization was observed with a catalyst consisting of diethylzinc and a tertiary-butyl substituted a-glycol221,222. ... 

Cationic copolymerization of sulfur dioxide and propylene oxide was studied and the product was identified as polysulfite ethers180,2S3 ... 

Random copolymerization of propylene oxide with ethylene oxide proceeded smoothly with the Nd(2-EP)3/AlEt3/H20 system at 80 °C [59]. From... 

Although the copolymerization of propylene oxide with C02 takes place effectively with organozinc additives or the (tetraphenyl) porphyrin-AlCl system [61], the copolymerization of epichlorohydrin with C02 seldom occurs with these catalysts. Shen et al. [62] showed that a rare earth metal catalyst such as the Nd(2-EP)3/AliBu3 (Al/Nd = 8) system was very effective for the copolymerization of epichlorohydrin with C02 (30-40 atm) at 60 °C (Scheme 16). The content of C02 in the copolymer reached 23-24 mol % when 1,4-dioxane was used as solvent. 

The FD mass spectra provide qualitative distribution of various species in HTE polymers. Most importantly, the spectra also provide the structural information to prove the incorporation of one unit of modifier, ethylene glycol or water, in HTE polymers. This is also the first analysis that distinguishes HTE polymers synthesized in conjunction with ethylene glycol and water. The incorporation of one unit of modifier into the polymer chain has been estimated semi-quantitatively with H NMR method for the copolymerization of tetrahydrofuran and propylene oxide in conjunction with 1,4-butanediol as a modifier (7). 

Kinetic resolution of propylene oxide in its alternating copolymerization with CO2 is performed using similar Co-salen complexes. Reaction conditions,... 

Fig. 11 Bifunctional cobalt catalysts for propylene oxide and COg copolymerization...

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...

Scheme 7 Mechanistic aspects associated with the copolymerization of propylene oxide and CO2 in the presence of a tethered organic base...

Because of the enhanced effectiveness of the cobalt(III) complex with piperidinium end-capping arms (Scheme 6) compared to standard (salen)CoX catalysts for the copolymerization of propylene oxide and CO2, Nozaki and coworkers were able to prepare in a stepwise manner a tapered block terpolymer by first copolymerizing propylene oxide/C02 followed by 1-hexene oxide/C02 [31]. 

Soga K, Imai E, Hattori I (1981) Alternating copolymerization of CO2 and propylene oxide with the catalysts prepared from Zn(OH)2 and various carboxylic acids. Polym J 13(4) 407 10... 

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... 

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 (2003) Block copolymerization of carbon dioxide with butylene oxide, propylene oxide and 4-vinyl-1-cyclohexene-1,2-epoxide in based poly (cyclohexene carbonate). J Chin Inst Chem Eng 34 335-344... 

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... 

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