Kinetic stereocontrol of polydiene microstructures during polymerization of Nd-Al bimetallic systems

Sabirov, Z. M.; Monakov, Yu. B.; Толстиков, Г. А.

doi:10.1016/0304-5102(89)80183-x

Cited by 9 publications

(4 citation statements)

References 15 publications

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“…It was the increase of distance difference between Nd-Cl and Nd-C bonds that leads the split of the main coordination peak when IP was mixed with the Nd-based ternary catalyst. Sabirov et al 28 carried out quantum chemical calculations for models of the active centers involved in butadiene polymerization in the presence of Nd-Al catalytic systems. Two shorter distances (2.0 and 2.4 A) between the crotyl group and the Nd atom are obtained.…”

Section: Polymerization Processmentioning

confidence: 99%

“…A modied insertion mechanism for isoprene polymerization was proposed on the base of structural information. Besides, Sabirov, 27, 28 Iovu, 29, 30 Evans, 10 and many researchers, [31][32][33] also made efforts to gure out the active center and/or polymerization mechanism of Nd-based catalyst. In fact, understanding the working mechanism of the complex Nd-based catalysts cannot do without in situ structural information and structure evolution.…”

Section: Introductionmentioning

confidence: 99%

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In situ X-ray absorption fine structure study on the polymerization of isoprene assisted by Nd-based ternary catalysts

Guo

et al. 2017

RSC Adv.

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Section: Polymerization Processmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

In situ X-ray absorption fine structure study on the polymerization of isoprene assisted by Nd-based ternary catalysts

Guo

et al. 2017

RSC Adv.

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“…From the perspective of microstructure contents, the 1,2‐unit contents of AlEt 2 (OPhCH 3 ) and AlEt(OPhCH 3 ) 2 were the largest, 89.1 and 90.6, respectively, and their cis ‐1,4 contents were almost similar at 0.2 and 0.23, respectively. According to the diolefin π‐allylic insertion mechanism proposed by Taube and coworkers, the syn‐η 3 ‐allyl could form a cis ‐1,4‐PB structure, and the anti‐η 3 ‐allyl could form 1,2‐PB and trans ‐1,4‐PB structures, as illustrated in Figure . Taube et al .…”

Section: Resultsmentioning

confidence: 99%

Effect of electronegativity and steric hindrance of the cocatalyst on the activity and selectivity of butadiene polymerization catalyzed by molybdenum

Liu

Geng

et al. 2018

J of Applied Polymer Sci

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Molybdenum‐based random 1,2‐polybutadiene (1,2‐PB) rubber, with its excellent wet skid resistance, low rolling resistance, and low heat buildup, can be used for green tread rubber, and it has significant benefits for the enhancement of the mechanical strength of 1,2‐PB. In this study, we investigated in detail the effects of the electronegativity and steric hindrance of the cocatalyst on the stereoselectivity of the resulting polymers. In the case of cocatalysts with moderate electronegativities, the active centers were more stable; this resulted in a larger molecular weight and a higher conversion, whereas a cocatalyst with excessive electronegativity tended to initiate cationic polymerization. The high sterically hindered substituent restricted the coordination configuration of the monomer; this ultimately resulted in the increase in the 1,2 structure to 90%. Fourier transform infrared analysis showed that the content of trans‐1,4 structure increased from 7 to 66%, and its crystallinity reached 59.2%, as calculated with differential scanning calorimetry when triethyl aluminum was used as the cocatalyst. Consequently, trans‐1,4‐polybutadiene crystals were introduced into the 1,2‐PB elastomer in one step; this could be a promising facile route for strengthening 1,2‐PB. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 136, 46906.

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“…Among the most prominant ones are transition metal-based catalysts including Ziegler or Ziegler-Natta type catalysts. The metals most frequently studied are Ti (203,204), Mo (205), Co (206)(207)(208), Cr (206)(207)(208), Ni (209,210), V (205), Nd (211)(212)(213)(214)(215), and other lanthanides (216 have been used commercially. It has long been recognized that by varying the catalyst compositions, the trans/cis ratio for 1,4-additions can be controlled quite selectively (204).…”

Section: Vol 4 Butadienementioning

confidence: 99%

Butadiene

Sun

Wristers

2002

Kirk-Othmer Encyclopedia of Chemical Technology

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Butadiene, C 4 H 6 , exists in two isomeric forms: 1,3‐butadiene and 1,2‐butadiene. 1,3‐Butadiene is a commodity product of the petrochemical industry. Elastomers consume the bulk of 1,3‐butadiene, led by the manufacture of styrene–butadiene rubber (SBR). 1,3‐Butadiene is manufactured primarily as a coproduct of steam cracking to produce ethylene in the United States, Western Europe, and Japan. However, in certain parts of the world it is still produced from ethanol. The other isomer, 1,2‐butadiene, has no significant current commercial interests. 1,3‐Butadiene is a noncorrosive, colorless, flammable gas at room temperature and atmospheric pressure. It has a mildly aromatic odor. It is sparingly soluble in water, slightly soluble in methanol and ethanol, and soluble in organic solvents like diethyl ether, benzene, and carbon tetrachloride. The conjugated double bonds of 1,3‐butadiene allow a large number of reactions at both the 1,2‐ and 1,4‐positions. These reactions include addition, hydrogenation, oxidation, Diels–Alder, oligomerization, and polymerization reactions. Many of these reactions produce large volumes of important industrial materials. Butadiene reacts with a large number of chemicals, has an inherent tendency to dimerize and polymerize, and is toxic. Therefore, specific handling, storage, and shipping procedures must be followed. U.S. shipments of butadiene, which is classified as a flammable compressed gas, are regulated by the Department of Transportation. Short‐term exposure to high concentrations of butadiene may cause irritation to the eyes, nose, and throat. Dermatitis and frostbite may result from exposure to the liquid and the evaporating gas. In several epidemiological studies, elevation in mortality was observed for small subgroups and tumor types. Updated exposure limits are given. Butadiene is used primarly in polymers. Other uses are given.

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Kinetic stereocontrol of polydiene microstructures during polymerization of Nd-Al bimetallic systems

Cited by 9 publications

References 15 publications

In situ X-ray absorption fine structure study on the polymerization of isoprene assisted by Nd-based ternary catalysts

In situ X-ray absorption fine structure study on the polymerization of isoprene assisted by Nd-based ternary catalysts

Effect of electronegativity and steric hindrance of the cocatalyst on the activity and selectivity of butadiene polymerization catalyzed by molybdenum

Butadiene

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