Oxidized propylene—amine system

In order to find a highly stereospedfic, homogeneous catalyst for the polymerization of propylene oxide, we selected the organometallic compound-primary amine catalyst system which exhibited excellent stereospecificity in the polymerization of acetaldehyde. 

Acetonitrile and benzonitrile, aliphatic amines, pyridine, amides (especially DMF), alcohols, and propylene-carbonate are used as solvents in the syntheses of this type. All of them have properties of ligands. Moreover, such classic N-donors as 2,2 -bipy and 1,10-phen were used as ligands, as well as compounds with P-(triphenylphosphine) and O- donor centers (urea, pyridine-N-oxide, triphenyl-phosphinoxide) and chelating ligand systems ((3-diketones, 8-hydroxyquinoline, dimethylglioxime) [202]. 

It is worth noting that catalysts formed in systems such as diethylzinc water, alcohol and primary or secondary amine, exhibiting high activity for the homopolymerisation of propylene oxide, were not effective for the copolymerisation of propylene oxide and carbon disulphide [248],... 

For poly(propylene oxide) ammonium (PPO-NH3 )/Na -montmorillonite models, some Na cations were removed from the amine-based model, and some amine functional groups were protonated so as to maintain the electroneutrality of the whole system. 

A special case of stereoelectivity has been encountered in polymerizing a racemic monomer with an optically active one. Minoura et al. (158) carried out the ring-opening copolymerization of propylene oxide with d-camphoric acid anhydride using diethyl zinc and triethyl amine as catalyst. It was found that the products were alternating copolymers which were optically active. The propylene oxide recovered from the copolymerization system was also optically active. An attempt to incorporate preferentially in a polyamide chain one of the optical antipodes of trans-cyclopropane-1,2-dicarbonyl chloride, by polycondensing this racemic monomer with optically active 1,2-propylene diamine failed (159). 

More flexible, tougher products can be obtained by using liquid diamines or polyamines having more flexible backbones. For example, Jeflamine T.403 (Texaco Chemical) is a low-viscosity liquid (70 mPa s) having a molecular weight of about 440 and an amine equivalent weight of about 145. It is a poly-(propylene oxide) triamine made from the polyether initiated by trimethylol propane, and is promoted as a flexible cross-linker for epoxy systems. 

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