New coordination catalysts based on rare‐earth compounds for the stereospecific polymerization of acetylene

Exploitation of rare earth catalysts in polymer syntheses

“…Molar ratio of Cl/Ln affects catalytic activity and the phase of the catalytic system greatly. Most researches of diene polymerization use rare earth carbonate such as rare earth C 5−9 carbonate, rare earth C 9−11 carbonate [Ln(vers) 3 ] and rare earth naphthenate. Among these, rare earth naphthenate is often used due to it easy solubility in aliphatic hydrocarbon and preparation and higher activity under proper conditions.…”

“…Copolymer containing 40 mol% styrene and isoprene unit of cis-1,4 content above 85% were prepared by Nd(acac) 3 -Mg(n-Bu) 2 -CHCl 3 system, with which the monomer reactivity ratios of isoprene and styrene under typical conditions r Ip =5.4, r St =0.38 were found. NdCl 3 ·HMPA-Al(i-Bu) 3 system also is an effective catalytic system for the copolymerization of styrene with isoprene [40]. We also found that block copolymers of isoprene with epichlorohydrin, isoprene with butyl methacrylate, isoprene with methyl methacrylate, isoprene with 1,2-cyclo hexane-oxide and isoprene with acrylnitrile could be prepared by ternary rare earth catalytic system: Nd(P 204 ) 3 -Al(i-Bu) 3 -BrCH 2 CH 2 Br using sequencial addition mode of the monomers.…”

“…The detailed polymerization regularity of acetylene by all sixteen rare earth elements: Sc, Y, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu naphthenate, phophonate and isopropoxide combined with trialkyl aluminum had been investigated. The scandium system shows fair activity in acetylene polymerization, although its activity in diene polymerization is small [3,43]. The catalytic activity sequence of rare earth naphthenate for acetylene polymerization at 30°C is as follows: Y, Ce > Nd, Yb > Pr, La > Lu, Gd > Tm, Er > Ho, Yb, Eu > Sm > Dy > Sc.…”

“…Abundant resources of rare earth ores (over half of whole world) in China has challenged our interest in investigation of using compounds of rare earth element (Group IIIB element) as new type of Ziegler-Natta catalysts. Early in the 1960's we scouted rare earth catalytic systems composed of rare earth chloride or rare earth diketonate with alkyl aluminum as heterogeneous or homogeneous butadiene polymerization catalysts for the first time [1,2]. A new family of rare earth coordination catalysts with high activity and high stereospecificity in polymerizations of conjugated dienes has been successfully developed since then.…”

“…In order to further explore the new applications of rare earth catalysts in polymer syntheses, Zhejiang University has exploited rare earth catalysts for cis-polymerization of acetylene at room temperature in 1981 [3,4], for phenyl acetylene and alkyl acetylene polymerizations in 1982 and 1983 [5] and preparing directly poly(phenyl acetylene) film [6]. Since 1985 we have been the first to carry out the studies of exploiting rare earth catalysts for ring-opening polymerizations of ethylene oxide, propylene oxide, epichlorohydrin, thiirane, chloromethyl thiirane [7−9], for ring-opening polymerizations of lactide, ε-caprolacton, and cyclic carbonate [10−12] and copolymerizations of CO 2 -oxirane [13], oxirane-maleic anhydride [14], styrenemaleic anhydride, styrene-acrylate [15]; polymerization of acrylate [16] and oligomerizations of ethylene or octane [17] and so forth.…”