Catalyst copolymerization

The above subject has been selected as an example of the design of new polymerization reactions. It is concerned with a concept of copolymerization by spontaneous initiation and subsequent propagation via zwitterion intermediates. This copolymerization, which was invented and has been developed by the author, is called no catalyst copolymerization . It is very characteristic since usual polymerization reactions require either an initiator or a catalyst. 

The concept of no catalyst copolymerization has demonstrated its usefulness in the exploration of phosphorus-containing polymers. For example, the cyclic phosphonite 34 was successfully copolymerized both with p-propiolactone (31) and acrylic acid 35). These copolymerizations proceed via a common zwitterion 36 and hence produce the same copolymer 37. 

The results of the MD simulations clearly demonstrate that the insertion starting from the higher energy isomers of the ethylene-chelate complexes in which the chelating bond has been broken have much smaller activation barriers, that are comparable to those observed in ethylene homopolymerization. This, however, does not explain the differences in the copolymerization activity of Pd and Ni-diimine complexes, as the barriers for the ethylene insertion into Ni-alkyl bond are smaller (14.2 kcal/mol) than those for Pd-alkyl bond (16.8 kcal/mol). Thus, it may be concluded that the ethylene insertion following the insertion of the polar monomer is not a crucial factor for the diimine catalyst copolymerization activity. It is the initial poisoning of the catalyst by formation of the... 

A major objective of our research has been to introduce polar groups into polyolefin molecules. With the anionic type of catalysts, copolymerization is very difficult because most nonhydrocarbon vinylic monomers deactivate the catalyst system and stop olefinic polymerization. However, by the AFR route, the desired olefin is completely polymerized before polar monomers are introduced so that high yields of product are possible. 

ZrCh, but forms a supported activator when contacted with MAO. This catalyst copolymerizes ethylene and 1-octene to a copolymer little different in its comonomer distribution from that prepared using a homogeneous catalyst. 2 ... 

Ammonia Dibutyltin maleate Dibutyltin oxide Fluorosulfonic acid Phosphine Sodium ethylate Sodium hydride Tetrabutyl titanate Tetraisopropyl titanate p-Toluene sulfonic acid Zirconium butoxide catalyst, condensation reactions Dibutyltin diacetate Piperidine catalyst, conductive polymers Iron (III) toluenesulfonate catalyst, conversion of acetylene to acetaldehyde Mercury sulfate (ic) catalyst, copolymerization Di butyl ether catalyst, cracking Zeolite synthetic... 

T. Saegusa, S. Kobayashi, and Y. Kimura, No catalyst copolymerization by spontaneous initiation mechanism. Pure Appl. Chem. 48, 307-315 (1976). 

A number of metal-catalyzed polymerizations have utilized CO2 as both a solvent and as a reagent in the reactions. Precipitation copolymerization of either propylene oxide (83) or cyclohexene oxide (84) with CO2 in SCCO2 has been catalyzed using heterogeneous zinc catalysts. Copolymerizations of CO2 and propylene oxide formed PCs with a molecular weight of about 10 g/mol and incorporation of CO2 at greater than 90% (eq. (7)). A small percentage of propylene carbonate by-product was also observed. 

Recent progress has also been made in the area of homo- and copolymerization of polar monomers. For instance, metallocene catalysts copolymerize ethene with 11-undecene-l-ol to yield hydroxy-functional LLDPE exhibiting improved adhesion [29]. Metallocenes based upon lanthanoids, as developed by Yasuda et al, copolymerize non-polar and polar monomers to produce new families of block copolymers, e.g., polypropylene-block-polymethylmethacrylate [30]. 

In principle, such protection using the carboxylate salt is feasible, but an exchange of the metal cation coordinated to the carboxylate salt has to be taken into account. This would lead to a transfer of the protected olefin between the titanocene and the active catalyst. Copolymerization experiments of Tim/Iia with ethene lead to the desired titanocene-protected copolymers in yields comparable to ethene homopolymerization. Hydrochlorination of the protected polymer regenerates the protecting Cp2TiCl and the free carboxylic acid of the polymer (Scheme 19). 

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