Butadiene Polymerization Catalyzed by Tri(aryloxo)aluminum Adduct of Cobalt Acetate

Abstract

Tris(2-phenylphenoxo)aluminum ((2-PhC 6 H 4 O) 3 Al) exists as a dimeric form in toluene. When toluene-insoluble anhydrous cobalt acetate is treated with tris(2-phenylphenoxo)aluminum in toluene, the toluene-soluble adduct (2-PhC 6 H 4 O) 3 Al·Co(OAc) 2 is formed. The 2-phenylphenoxo ligand in the adduct can be replaced with another aryloxo ligand to give (aryloxo)(2-PhC 6 H 4 O) 2 Al·Co(OAc) 2 (aryloxo = 2-methylphenoxo, 2-isopropylphenoxo, 4-methylphenoxo, 4-isopropylphenoxo, or 4-tert-butylphenoxo). These complexes are active for butadiene polymerization without gel formation when activated with an equivalent amount of (2-PhC 6 H 4 O)AlEt 2 for 2 h. The highest activity, 175 kg/mol-Co (turnover number, 3200) was achieved with (2-PhC 6 H 4 O) 3 Al·Co(OAc) 2 at 65 o C for 2 h. The microstructure of the polymer chains is mostly trans-1,4-configuration (70-75%) with the remaining being 1,2-vinyl. The cis-1,4-configuration observed by IR is minimal (1-5%). By replacing the 2-phenylpheoxo with a 4-alkylphenoxo ligand, the amount of 1,4-configuration slightly increases, resulting in increase in the endothermic melting signal at −30~50 o C in the DSC curve. The molecular weights of the polymers are high (M n : 300000~800000) with a fairly narrow molecular weight distribution (M w /M n , 2.0-2.7).

The influence of Ni/Nd‐based Ziegler–Natta catalyst on microstructure configurations and properties of butadiene rubber

“…Moreover, the results in Table showed that the gel content of Ni/Nd‐BR (0.55%) was much lower than that of the commercial Ni‐BR (1.47%). This implied that the existing vinyl −1,2 configuration could induce the gel formation via re‐incorporation of internal unsaturation units for Ni‐BR system …”

1,3‐butadiene polymerization using Co/Nd‐based Ziegler/Natta catalyst: Microstructures and properties of butadiene rubber

“…13 C-NMR spectroscopy (Fig. 2b) shows important signals with a chemical shift of 27.4, 32.7, and 34.0 ppm attributed to 1,4-cis-methylene, -CH 2 -of 1,4-trans structure and vinyl-1,2-enchainment, respectively [12]. This observation was also consistent with the result from 1 H-NMR spectroscopy which exhibited very low signal intensity for the vinyl21,2 configuration of Co/Nd-BR.…”

“…0.04%. It is likely that the existing vinyl21,2 configuration could easily induce the gel formation in BR via re-incorporation of internal unsaturation units for the Co-BR [5,12]. Effect of Molar Co/Nd Ratio.…”

Modelagem E Simulação Da Polimerização Do 1,3-Butadieno via Catalisador De Múltiplos Sítios

“…Existem algumas formas de se realizar a reação de polimerização do butadieno partindo-se de diferentes iniciadores ou catalisadores porém, a principal forma de se realizar esta polimerização é a partir da polimerização por coordenação com a utilização de catalisadores Ziegler-Natta (PIRES; COUTINHO; COSTA, 2004a). Os catalisadores Ziegler-Natta costumam ser à base de titânio (RICCI et al, 1996), cobalto (GIPPIN, 1962;PARK et al, 2012;TAKEUCHI et al 1992), níquel (DIXON et al, 1970) e neodímio (FERREIRA, 2009).…”