In this paper, poly-α-olefins
(PAO) containing quaternary
carbon centers were prepared by two-step oligomerization using a metallocene
catalyst followed by a Ziegler–Natta catalyst. First, the 1-decene
dimer was oligomerized with [t-BuN(Me)2C(η5-C5H4)]ZrCl2, and the effects of the oligomerization temperature, Al/Zr molar
ratio, and catalyst loading on the oligomerization were investigated.
In the second step, the obtained 1-decene dimers were copolymerized
with 1-decene with TiCl4/Et2AlCl, and the effects
of the catalysts, monomer/dimer ratio, and α-olefin species
on the copolymerization were investigated. The composition and structure
of the dimers and copolymerization products were characterized by
gas chromatography (GC) and 1H NMR and 13C NMR
spectroscopy. The results of GC and 13C NMR analyses indicated
that the metallocene catalyzed the formation of the 1-decene oligomerization
product, resulting in the branched olefin dimer being the major product,
and the existence of quaternary carbons in the 1-decene/1-decene dimer
copolymerization product could also be found. The polymerization mechanism
for the formation of the quaternary carbon centers is proposed. The
1-decene/1-decene dimer copolymerization product containing quaternary
carbon centers has a kinematic viscosity of 10.8 mm2/s
at 100 °C, a viscosity index of 165, and a pour point of −52
°C; thus, the product with quaternary carbon centers has a better
viscosity–temperature performance and low-temperature fluidity
than those of the 1-decene oligomerization product and typical PAO
products, but the kinematic viscosity is similar.
A two-carbon bridged diphosphine (PCCP) ligand bearing an ortho-methoxy substituent in the phosphine phenyl group has been synthesised and applied in Cr-catalysed ethylene tri-/tetramerization. Compared to previous catalysts, the Cr...
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