Propylene alternating copolymerization with

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

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) ... 

Palladium(II) complexes possessing bidentate ligands are known to efficiently catalyze the copolymerization of olefins with carbon monoxide to form polyketones.594-596 Sulfur dioxide is an attractive monomer for catalytic copolymerizations with olefins since S02, like CO, is known to undergo facile insertion reactions into a variety of transition metal-alkyl bonds. Indeed, Drent has patented alternating copolymerization of ethylene with S02 using various palladium(II) complexes.597 In 1998, Sen and coworkers also reported that [(dppp)PdMe(NCMe)]BF4 was an effective catalyst for the copolymerization of S02 with ethylene, propylene, and cyclopentene.598 There is a report of the insertion reactions of S02 into PdII-methyl bonds and the attempted spectroscopic detection of the copolymerization of ethylene and S02.599... 

Alternating Copolymerization. In the last part of this paper we would like to refer briefly to our findings in connection with the alternating copolymerization of dienes with olefins. The alternating copolymerization of butadiene with propylene was first investigated in 1969 by Furukawa and others (15, 16, 17). They used catalyst systems based on titanium or vanadium compounds. 

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... 

Leclerc and Waymouth (119) and, independently, Arndt et al. (120) synthesized alternating copolymers of ethylene and propylene with zirconocene catalysts. The ethylene/propylene (EP) copolymerizations were carried out at 30 and 60°C for each of four metallocene catalysts (Me2C(3-RCp)(Flu)) ZrCl2 (R = H, Me, lsoPr, tertBu) (Fig. 10). As the size of the substituent increased, there were distinct changes in the copolymerization behavior and in the polymer microstructure. 

Figure 5. Alternating copolymerization of propylene oxide (PO) and phthalie anhydride (PA) with the TPPAlCl-Et3PhPBr system. fPOl = IP I/ [Cat] s 25, in CH2C12 at room temperature.

Radiation induced copolymerization of hexafluoroacetone xcith a-olefins has been done over a broad temperature range. From these experiments, it was confirmed that ethylene can be copolymerized below its critical temperature to give an alternating copolymer. A radical mechanism is involved at relatively high temperatures below —10°C, the mechanism has been confirmed to be ionic and may be cationic. Propylene can be copolymerized in a way similar to that of ethylene however, the rate of copolymerization was much slower. Isobutylene did not copolymerize with hexafluoroacetone at 0°C. A 1 2 adduct compound was obtained as the main product. At low temperatures, copolymerization proceeds to some extent. 

Tan, C. S. and Hsu, T. J. (1997), Alternating copolymerization of carbon dioxide and propylene oxide with a rare earth metal coordination catalyst. Macromolecules, 30, 3147-3150. 

Apart from the major reviews, numerous publications have appeared in the last two years which report new monomer combinations for alternating copolymerization or which seek to throw light on the numerous problems which still exist in this burgeoning field of study. Many comonomer systems have been reported in the last two years which give rise to alternating copolymers by one or more of the mechanisms which have been outlined, including acrylonitrile with acenaphthalene, cyclopenta-1,3-diene p-aminostyrene with p-nitro-styrene and other vinyl monomers butadiene with 1,2-dicarbomethoxy ethylenes, acrylonitrile, propylene, and others isoprene with mono-... 

Polymers can be made with a single repeating unit these are homopolymers. The repeating unit can be varied to form copolymers. For example, if ethylene is copolymerized with propylene, a copolymer can be formed. Depending on the reaction conditions and the reactivity of the different monomers, copolymers can be alternating, random, or block. This is illustrated with polymers made from monomers X and Y. 

Let us also mention some asymmetric-selective copolymerizations with propylene oxide (PO) it could be expected that another chiral co-monomer would favor the asymmetric-selection of one of both co-monomers. Tsuruta etal.[ S 2i] reported the asymmetric-selection copolymerization of 3-phenyl-4-tetrahydrophthalic acid anhydride with PO (LXI). Minoura et al [152] described the alternating copolymerization of PO and d-camphoric acid anhydride with diethylzinc triethylamine as optically inactive initiator the... 

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