Chemistry is an experimental science, Recommanded Product: Titanocenedichloride, and the best way to enjoy it and learn about it is performing experiments.Introducing a new discovery about 1271-19-8, Name is Titanocenedichloride
Living organotitanium(IV)-catalyzed polymerizations of isocyanates
An organotitanium(IV) compound, TiCl3OCH2CF3, 1, was found to polymerize n-hexyl isocyanate to high yields and without the formation of cyclic trimer. CpTiCl2L (L = -OCH2CF3, -N(CH3)2, -CH3), 2-4, respectively, likewise polymerized n-hexyl isocyanate but also polymerized isocyanates in the presence of donor solvents and isocyanates possessing donor functional groups, activated olefins, and strained olefins. The activity of the organotitanium(IV) catalysts decreased with increasing steric bulk about the metal center and increasing electron donation to the metal center from the ligands. The polymerization of n-hexyl isocyanate using organotitanium(IV) compounds is living. The PDIs of PHIC synthesized using catalysts 1-4 were found to range from 1.05 to 1.2. The molecular weight of the polymer formed in polymerizations of n-hexyl isocyanate using catalysts 1-4 varied linearly as a function of the monomer-to-initiator ratio and the percent conversion of the polymerization. Polymerizations using 2 can be endcapped quantitatively, and well-defined block copolymers can be synthesized using catalysts 1-4. The kinetics for polymerizations using catalysts 1 and 2 are first-order in both monomer and catalyst (k1 = 8.5 x 10-4 mol L-1 s-1, k-1 = 3.8 x 10-4 s-1). The active endgroup of a polymerization using 3 was observed using IR spectroscopy, and the frequency of the IR stretch (1548 cm-1) was consistent with an eta2-amidate endgroup structure. Finally, the kinetic data for the polymerization of n-hexyl isocyanate and the known chemistry of CpTiCl2L compounds were found to be consistent with a propagation step that occurs via a bifunctional activation mechanism.
Sometimes chemists are able to propose two or more mechanisms that are consistent with the available data. Recommanded Product: Titanocenedichloride, If a proposed mechanism predicts the wrong experimental rate law, however, the mechanism must be incorrect.Welcome to check out more blogs about 1271-19-8, in my other articles.
Reference£º
Metal catalyst and ligand design,
Ligand Template Strategies for Catalyst Encapsulation – NCBI