Soluble neodymium chloride 2-ethylhexanol complex as a highly active catalyst for controlled isoprene polymerization

Ren, Cuilan; Li, Guilian; Dong, Weimin; Jiang, Liansheng; Zhang, Xuequan

doi:10.1016/j.polymer.2007.02.027

Cited by 52 publications

(37 citation statements)

References 22 publications

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“…Polymyrcenes with ∼97 % of the cis ‐1,4 microstructure were obtained, which were shown to be independent on the [Al]/[Nd] ratio, agreeing with results in other works related to Nd‐catalyzed polymerization of 1,3‐diene monomers . On the other hand, when the [B]/[Nd] ratio increased from 0.9 to 1.5, the cis ‐1,4 content decreased slightly from 93.0 % to 91.9 %.…”

Section: Resultssupporting

confidence: 89%

Synthesis and characterization of high cis‐polymyrcene using neodymium‐based catalysts

et al. 2016

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The monomer β‐myrcene, a renewable resource, was polymerized in cyclohexane using two different Ziegler‐Natta catalyst systems based on neodymium Nd(Oi‐Pr)3 and NdV3. The Nd(Oi‐Pr)3 was combined with [HNMe2Ph][B(C6F5)4] (or [CPh3][B(C6F5)4]) and Al(i‐Bu)3 (or Al(i‐Bu)2H). Next, the NdV3 was activated using Al(i‐Bu)3 and AlEt2Cl. Both catalyst systems exhibited high polymer yields near 100 % in the established reaction time, high polymer molecular masses, and broad molecular mass distributions. The catalyst systems gave an effective and stereospecific polymerization reaction of β‐myrcene providing high cis selectivity of 1,4‐polymyrcenes (> 92 %) with a glass transition temperature between −66 and −62 °C. The above‐mentioned features of resulting elastomers in conjunction with the polymer's molecular masses and molecular mass distributions proved to be sensitive to borane and alkylaluminum compounds molar ratios, [B]/[Nd] and [Al]/[Nd] using Nd(Oi‐Pr)3 and [Cl]/[Nd] and [Al]/[Nd] with NdV3.

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Section: Resultssupporting

confidence: 89%

Synthesis and characterization of high cis‐polymyrcene using neodymium‐based catalysts

et al. 2016

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“…However, Samples I, II, III, and IV seem to have quite weak medium-range-ordered structures, but the higher-shell coordination peaks of Samples V and VI can be neglected. Due to the low Al : Nd ratio effects, 21 Sample II cannot exhibit catalytic properties. For Sample I, its near-neighbor coordination peak is located at 1.92 Å which can be mainly ascribed to the coordinated O atoms as indicated by the molecular structure of Nd(vers) 3 as shown in Fig.…”

Section: Resultsmentioning

confidence: 99%

“…Therefore, it can be concluded that the addition of Al( i Bu) 2 Cl into the mixture solution reduces the Nd-alkyl bonds slightly, and introduces Al atoms to the next-nearest-neighbors of Nd centers. Besides, the concentration of Al(III) 21 was considered to have a more significant effect on the molecular weight and the molecular weight distribution as compared to the concentration of Nd (III), and to be an efficient molecular weight regulator in isoprene polymerization with the binary NdCl 3 ·3EHOH/AlEt 3 catalyst system. Perhaps, it is the high dispersibility of Nd(vers) 3 that improves greatly its catalytic activity.…”

Section: Dalton Transactions Papermentioning

confidence: 99%

Local structure analysis around the Nd center in a ternary catalyst comprising Nd(vers)₃, Al(ⁱBu)₃ and Al(ⁱBu)₂Cl by XAFS

Guo

Wang

et al. 2015

Dalton Trans.

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Lanthanide-based catalysts are highly active for isoprene polymerization in hexane. In this paper, a ternary catalyst consisting of neodymium neodecanoate {Nd(vers)3}, Al((i)Bu)3 and Al((i)Bu)2Cl was studied by using X-ray-absorption fine-structure (XAFS) technique. A sealed and moisture-proof liquid sample cell with adjustable thickness was designed for Nd LIII-edge XAFS measurements. Based on the XAFS data analysis, detailed structure changes around the Nd center were obtained. It was found that the Nd(vers)3 molecules formed an oligomer structure in hexane solution with two Nd-O subshells (5O @ 2.39 Å and 5O @ 2.54 Å) around the Nd center. The alkylation process by adding Al((i)Bu)3 to the hexane solution of Nd(vers)3 partially destroyed the aggregation degree of Nd(vers)3 molecules in hexane solution. Al((i)Bu)3 ligands were bonded to the Nd center by Nd-C bonding. With the Nd : Al ratio increasing from 1 : 2.5 to 1 : 10, the O neighbors around Nd decreased from 4 to 2 but with an unchanged Nd-O bond length of 2.38 Å, and the C neighbors around Nd were kept at ca. 4 with Nd-C bond lengths in the range of 2.57-2.58 Å. The Nd-O bonds can be further replaced by Nd-C bonds during the aging process. The chlorination process by adding Al((i)Bu)2Cl to the mixture solution of Nd(vers)3 and Al((i)Bu)3 restrained intensively the agglomeration of Nd(vers)3 molecules in hexane solution. Al((i)Bu)2Cl ligands were bonded to the Nd center by Nd-Cl bonds. There were about 3-4 C neighbors at 2.58 Å, 2 Cl neighbors at 2.87 Å, and 2 Al next-neighbors at 3.14 Å around the Nd center. After allowing the ternary catalyst to stand for 5 days, the coordination numbers of Nd-C and Nd-Cl were all stabilized to 3 without bond length changes, and partial single Cl(-) anions were also bonded to the Nd center. All these structural details and their change tendency demonstrate that the decrease of aggregation degree of Nd(vers)3 molecules in hexane solution can improve the catalytic activity of the ternary lanthanide-based catalyst system.

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“…Isoprene polymerization catalyzed by NdCl 3 ⋅3EtOH (or 2-ethyl hexanol)/AlEt 3 [7] (at Al/Nd (molar ratios) < 20) leads to formation of high cis-1,4 polyisoprene (96%) at high polymerization activity and narrow molecular weight distribution (2.0). Compared with the covalent nature of the Ti-Cl bond in TiCl 4 , the Ln-Cl bond in LnCl 3 is more ionic.…”

Section: Catalyst Typementioning

confidence: 99%

“…In the early 1960s, Shen and her colleagues at the Changchun Institute of Applied Chemistry, Chinese Academy of Sciences (CIAC) found the catalytic activities of lanthanide compounds in stereospecific polymerization of conjugated dienes and published the first paper on this topic in 1964 [1,2] . On the basis of this finding, CIAC launched extensive research activities on lanthanide compounds as diene polymerization catalysts, including stereospecific polymerization of butadiene [2,3] and isoprene [4,5] , and copolymerization of butadiene and isoprene [6,7] . The characteristics of rare earth catalysts are demonstrated and elucidated as follows: (1) high catalytic activity for polymerization of dienes (molar ratio of Ln/butadiene or isoprene = 0.3 × 10 −4 , conversion more than 80%); (2) high cis-1,4 contents (more than 95%); (3) in the copolymer of butadiene and isoprene, both butadiene and isoprene units have high cis-1,4 configuration (more than 95%).…”

Section: Introductionmentioning

confidence: 99%

Synthetic rubbers prepared by lanthanide coordination catalysts

Chen

2009

Sci. China Ser. B-Chem.

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China is rich in rare earth resources. Rare earth elements, also named lanthanides, are number 58 to number 81 elements in the elemental periodic table. They have unique electronic structures and may form various coordination compounds. In the early 1960s, researchers at the Changchun Institute of Applied Chemistry, Chinese Academy of Sciences (CIAC) found the catalytic activities of lanthanide compounds in stereospecific polymerization of conjugated dienes, and published the first paper on this topic in 1964. On the basis of this finding, CIAC launched extensive research activities on lanthanide compounds as diene polymerization catalysts, from a series of fundamental research to the efforts of industrializing the rare earth catalyzed cis-1,4-polybutatine rubber and cis-1,4-polyisoprene rubber. This review aims to summarize the progress in this field in the past half century.

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Soluble neodymium chloride 2-ethylhexanol complex as a highly active catalyst for controlled isoprene polymerization

Cited by 52 publications

References 22 publications

Synthesis and characterization of high cis‐polymyrcene using neodymium‐based catalysts

Synthesis and characterization of high cis‐polymyrcene using neodymium‐based catalysts

Local structure analysis around the Nd center in a ternary catalyst comprising Nd(vers)₃, Al(ⁱBu)₃ and Al(ⁱBu)₂Cl by XAFS

Synthetic rubbers prepared by lanthanide coordination catalysts

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Soluble neodymium chloride 2-ethylhexanol complex as a highly active catalyst for controlled isoprene polymerization

Cited by 52 publications

References 22 publications

Synthesis and characterization of high cis‐polymyrcene using neodymium‐based catalysts

Synthesis and characterization of high cis‐polymyrcene using neodymium‐based catalysts

Local structure analysis around the Nd center in a ternary catalyst comprising Nd(vers)3, Al(iBu)3 and Al(iBu)2Cl by XAFS

Synthetic rubbers prepared by lanthanide coordination catalysts

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Local structure analysis around the Nd center in a ternary catalyst comprising Nd(vers)₃, Al(ⁱBu)₃ and Al(ⁱBu)₂Cl by XAFS