Chemistry, like all the natural sciences, Formula: C21H22N2O2, begins with the direct observation of nature¡ª in this case, of matter.131457-46-0, Name is (4S,4S)-2,2-(Propane-2,2-diyl)bis(4-phenyl-4,5-dihydrooxazole), SMILES is CC(C1=N[C@@H](C2=CC=CC=C2)CO1)(C3=N[C@@H](C4=CC=CC=C4)CO3)C, belongs to catalyst-ligand compound. In a document, author is Shi, Zi-hai, introduce the new discover.
Study on the Organometallic [N,P] Titanium Catalysts for Ethylene Polymerization without Cocatalyst
The soft and hard acid-base theory (HSAB) is a new acid-base theory created by Sir. Pearson based on the theory of Lewis acid-base electron. It can be used to explain various chemical reactions, especially in coordination chemistry. In this study, the synthesized Cat.1 – Cat.6 [N,P]Ti catalysts containing ligands with electron withdrawing groups were prepared for ethylene polymerization without the addition of cocatalyst. The other optimal conditions for ethylene polymerization were determined through optimizing the polymerization behavior. Cat.5 with ligand L5 containing tetrafluorobenzene ring showed a catalytic activity of to 2.83 x 10(5) g(P).(mol(M))(-1).h(-1) for this polymerization. The obtained polyethylene featured high weight average molecular weight of 8.6 x 10(5) g/mol. The molecular weight distribution of polyethylene obtained by these six catalysts were in 2.2-2.5, and the melting point was about 135 degrees C The reaction mechanism of ethylene polymerization was explored by HSAB. The results showed that when the substituent on the catalyst aniline was an electron withdrawing group, both the polymerization activity and the molecular weight of the obtained polymer were higher. Density Functional Theory (DFT) results indicated that ethylene was more inclined to react with one of the M-C bonds of the catalyst. The energy barrier for the ethylene insertion reaction by Cat.5 was the lowest, compared to other catalysts except Cat.1, which made ethylene insertion reaction easier. These ligands containing electron withdrawing groups on aniline ring made the catalytic active species more stable. Much higher molecular weight of polyethylene was produced by utilizing these catalysts with the ligands containing electron withdrawing groups on aniline ring. These experimental results were consistent with those of HSAB and DFT.
Note that a catalyst decreases the activation energy for both the forward and the reverse reactions and hence accelerates both the forward and the reverse reactions. you can also check out more blogs about 131457-46-0. Formula: C21H22N2O2.
Reference:
Metal catalyst and ligand design,
,Ligand Template Strategies for Catalyst Encapsulation – NCBI