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氯化钕配合物在4—乙烯吡啶聚合反应中的催化作用 总被引:3,自引:0,他引:3
氯化钕配合物是双烯烃聚合催化剂组分之一 ,与烷基铝所构成的二元体系对丁二烯聚合具有较佳活性 [1,2 ] ,但用氯化钕配合物催化极性单体的聚合反应尚未见报导 .极性单体的聚合是人们感兴趣的课题 ,例如 Benito等 [3 ]用过渡金属化合物 (VCl3-Al Et3)体系催化聚合 4-乙烯吡啶 (4VPy)极性单体 .但是它的催化活性较低 ,催化效率为 3.1×1 0 -4 kg· mol-1· h-1.我们研究了将含少量的氯化钕配合物催化剂用于该聚合反应 ,催化活性得到很大提高 ,催化效率达到 50 .71 Kg· mol-1· h-1.表明氯化钕配合物催化体系不仅对双烯烃而且对极性单体聚… 相似文献
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稀土羧酸盐,如辛酸盐,硬酯酸盐和环烷酸盐等组成的催化体系对共轭双烯烃聚合具有良好的活性和定向效应。但体系中要有第三组分的存在,通常采用的是烷基氯化铝,其作用是与羧酸盐羧基进行交换反应,是形成活性中心的必要条件。氯化稀土组成的体系由于自身组成含有氯离子而排除了第三组分的使用,从而简化了聚合工艺流程,有利于研究体系组分之间的反应。但是并非所有氯化稀土都适宜于这种研究,原因在于大多数氯化稀土络合物不溶于惰性有机溶剂。如氯化稀土醇合物对共轭双烯烃聚合有着相当高的活性,但是研究氯化稀土醇合物与烷基铝的反应却有着一定的困难。 相似文献
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本文研究了四种钕化物(C_8H_7NdCl_2·HCl·THF,C_5H_5NdCl_2·THT,NaCl_3·2THF或NaCl_3·C_6H_5OH·THF)分别与烷基铝所组成的新型催化体系引发丁二烯聚合反应动力学。上述各种体系当聚合温度50℃,[Al]/[Nd]摩尔比为30时,聚合历程均属缓慢引发非稳态反应类型:当[Al]/[Nd]摩尔比为60时,C_9H_7NdCl_2·HCl·THF体系聚合历程变 相似文献
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钕-铝双金属配合物催化异戊二烯聚合的原位环化反应 总被引:1,自引:0,他引:1
环化聚异戊二烯 (CPIP)具有优良的光敏性、较好的耐热性和力学性能 ,在光刻胶、胶粘剂、橡胶改性等方面得到广泛应用 [1,2 ] .CPIP可按阳离子机理经单体环聚或聚合物环化两种方法合成 .我们 [3]最近提出一种直接从单体出发在稀土催化聚合过程中引入烯丙基氯原位合成 CPIP的方法 .本文在此基础上 ,以三异丙氧基钕 -三乙基铝 -一氯二乙基铝均相体系中分离出的钕 -铝双金属配合物作为单组分催化剂 ,简化聚合体系 ,以便直观地考察氯化物、烷基铝等的作用 ,揭示稀土催化 IP聚合原位环化反应的过程 .1 实验部分 CPIP的合成参见文献 [… 相似文献
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Contributions to Organolanthanide Chemistry. II. Cyclopentadienyllanthanide 1,3-Butadiene Complexes – Synthesis, Properties, and Reactions From cyclopentadienyllanthanide dihalides and “magnesium butadiene” Cp*La(C4H6) · MgI2 · 3 THF ( I ), Cp*Ce(C4H6) · MgBr2 · 2 THF ( II ), Cp*Nd(C4H6) · MgCl2 · 2 THF ( III ), (1,3-(t-C4H9)2C5H3)Nd(C4H6) · MgCl2 · 2 THF ( IV ), CpEr(C4H6) · MgCl2 · 2 THF ( V ) and (1,3-(t-C4H9)2C5H3)Lu(C4H6) · MgCl2 · 2 THF ( VI ) were obtained as highly air sensitive complexes which react easily with proton active compounds and molecules with multible bonds. The reaction products with diphenylamine and carbon dioxide Cp*Nd(NPh2)2 · NHPh2 ( VII ) and Cp*Ce(O2CC4H6CO2) ( VIII ) are discribed. I–VIII were characterized by elementary analysis, i.r., 1H and 13C n.m.r., and EI-MS spectra. 相似文献
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The polymerization of butadiene in toluene initiated by the NdCl3 · 3TBP-Mg(C4H9)(i-C8H17) (TBP is tributyl phosphate) catalytic system has been studied. It has been shown that the polymerization reaction under study is a nonstationary slowly initiated process. The addition of carbon tetrachloride promotes an increase in the catalytic activity of the system. The products of polymerization have low molecular masses and polydispersity indexes. The content of 1,4-trans-units in the polymer is as high as 95%. 相似文献
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Tadeusz Biela Andrzej Duda 《Journal of polymer science. Part A, Polymer chemistry》1996,34(9):1807-1813
Kinetics of ϵ-caprolactone (ϵCL) polymerization initiated with diethylaluminum ethoxide in benzene (C6H6) and acetonitrile (CH3CN) as solvents was studied and compared with the previously studied polymerization conducted in tetrahydrofuran (THF) solvent. Kinetic data were analyzed in terms of the kinetic scheme: “propagation with aggregation,” assuming that actually propagating active species (Pn*) aggregate reversibly into the unreactive (dormant) species . The determined equilibrium constants of deaggregation (Kda) decrease with decreasing solvent polarity, namely Kda (in mol2·L−2) = (1.3 ± 0.7)·10−2 (CH3CN), (1.8 ± 0.5)·10−5 (THF), (4.1 ± 0.7)·10−6(C6H6), whereas for the rate constants of propagation the opposite is true, kp (in mol−1·L·s−1) = (7.5 ± 0.3)·10−3 (CH3CN), (3.87 ± 0.01)·10−2 (THF), (8.6 ± 0.9)·10−2 (C6H6) (25°C). The latter effect is explained by a specific solvation (the stronger the higher solvent polarity) of the active species already in the ground state in the elementary reaction of the poly(ϵCL) chain growth: C2H5[OC(O)(CH2)5]nO(SINGLE BOND)Al(C2H5)2 + ϵCL → C2H5[OC(O)(CH2)5]n+1O(SINGLE BOND)Al(C2H5)2. © 1996 John Wiley & Sons, Inc. 相似文献
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《Journal of organometallic chemistry》1987,322(1):57-63
The compound η5-C5H5NdCl2 · 3THF was successfully prepared from NaC5H5 and NdCl3 in tetrahydrofuran (THF). Methods preventing disproportionation are discussed.X-ray diffraction data of the compound were collected at low temperature (about 210 K). Crystals belong to monoclinic space group P21/n with a 7.864(3), b 17.198(7), c 15.212(5) Å, β = 94.46(3)°, Z = 4. 1791 reflections were considered observed. The structure was solved by heavy-atom methods. Least-squares refinement converged to a final value of R = 0.049. 相似文献
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Herbert Schumann Jrn Winterfeld Esther C. E. Rosenthal Holger Hemling Lothar Esser 《无机化学与普通化学杂志》1995,621(1):122-130
Organometallic Compounds of the Lanthanides. 88. Monomeric Lanthanide(III) Amides: Synthesis and X-Ray Crystal Structure of [Nd{N(C6H5)(SiMe3)}3(THF)], [Li(THF)2(μ-Cl)2Nd{N(C6H3Me2-2,6)(SiMe3)}2(THF)], and [ClNd{N(C6H3-iso-Pr2-2,6)(SiMe3)} 2(THF)] A series of lanthanide(III) amides [Ln{N(C6H5) · (SiMe3)}3(THF)x] [Ln = Y ( 1 ), La ( 2 ), Nd ( 3 ), Sm ( 4 ), Eu ( 5 ), Tb ( 6 ), Er ( 8 ), Yb ( 9 ), Lu ( 10 )] could be prepared by the reaction of lanthanide trichlorides, LnCl3, with LiN(C6H5)(SiMe3). Treatment of NdCl3(THF)2 and LuCl3(THF)3 with the lithium salts of the bulky amides [N(C6H3R2-2,6)(SiMe3)]? (R = Me, iso-Pr) results in the formation of the lanthanide diamides [Li(THF)2(μ-Cl)2Nd{N(C6H3Me2-2, 6)(SiMe3)}2(THF)] ( 11 ) and [ClLn{N(C6H3-iso-Pr2-2,6)(SiMe3)} 2(THF)] [Ln = Nd ( 12 ), Lu ( 13 )], respectively. The 1H- and 13C-NMR and mass spectra of the new compounds as well as the X-ray crystal structures of the neodymium derivatives 3 , 11 and 12 are discussed. 相似文献
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Electron-rich Phenyl Complexes of Transition Metals. II. Li4Co2(C6H5)4 · 4THF, Li4Co2(C6H5)4 · 3 Dioxan and Li3Co(C6H5)2(LiC6H5) · 5THF, the First Complexes with a Bis(phenyl)-cobalt(0)- and -cobalt(-I) Unity . Li2CoII(C6H5)4 · 4THF reacts spontaneously in benzene by splitting off of two phenyl radicals to a dimeric bis(phenyl) cobalt(0) complex which has been isolated as a THF and a dioxan adduct Li4Co2(C6H5)4 · 4THF and Li4Co2(C6H5)4 · 3 Dioxan, respectively. Reduction with lithiumphenyl in ether gives a phenyl cobalt(-I) complex Li4Co(C6H5)3 · 5THF containing besides σ-bonded phenyl anions lithium phenyl coordinated to cobalt in a π-complex like manner, proved by means of 13C? NMR-spectroscopy. The stabilization of the low oxidation states is explained by coordination of the lithium ions to cobalt by multiple center bonds, and for each compound a plausible structure is derived. 相似文献
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Contributions to the Chemistry of Organo Transition Metal Compounds. 52. Preparation, Characterization, and Reactions of (C5H5)3Ce · THF and Na[Ce(C5H5)4] · THF (C5H5)3 · THF ( I ) was synthesized in a simple manner by reaction of (NH4)2[Ce(NO3)6] with C5H5Na. With excess C5H5Na the complex Na[Ce(C5H5)4] · THF ( II ) could be obtained. In addition of cyclovoltammetric and polarographic measurements it was tried without success to transfer I and II into organocerium( IV ) compounds by means of different oxidizing agents. II reacts with I2 and (C6H5)3CCl forming Na[(C5H5)3CeI] · THF or Na[(C5H5)2CeI2] · 4 THF and I besides of (C6H5)3CCl respectively. At interaction of I with Co(acac)3 the cobalticinium salt [(C5H5)2Co][C5H5Ce(acac)3] is formed. The compounds obtained were characterized by elementary analysis, hydrolysis products, magnetic moments, i.r., 1H-n.m.r. und u.v.-vis spectra, and measurements of electric conductivity. 相似文献
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Kurt Schmiedeknecht 《无机化学与普通化学杂志》1971,379(3):286-292
The preparation of uncharged complexes with metal amide bonds of type [MeN4]±0 (Me = Zn2+, Cr2+ is reported. These compounds are obtained by the interaction between Zn(C6H5)2 or Cr(C6H5)3 · 3 THF and 2-[β-(phenyl-amino)-ethyl]-pyridine (I). The same complexes are formed by the reaction between ZnCl2 · 2 THF, CrBr2 · 2 THF, or CrCl3 · 3 THF and the lithium amide (II), which is prepared from (I) and phenyl lithium. The structure of the chromium(II) complex is discussed on the basis of magnetic and visible absorption measurements. 相似文献
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The Structure of an unusual Tetramere of Lithium Phenoxide: [C6H5OLi · C4H8O]4 · C6H5OH Single crystals of lithium phenoxide have been obtained from THF. In the structure (P 21/n, Z = 4, a = 11.69 Å, b = 21.15 Å, c = 18.55 Å, β = 91.11°) four lithium atoms and four phenoxide oxygen atoms are cubically arranged. Further, each lithium atom coordinates the oxygen atom of a tetrahydrofuran molecule. The ideal cubeform structure is disturbed by one phenol molecule which is coordinated in addition to four phenoxide and four THF molecules. Hence, one edge of the cube (Li4? O4) is substituted by the coordination of the phenol oxygen atom O5 with Li4 and hydrogen bonding between O4 and the hydroxy group of phenol. Van der Waals forces are the only interaction between these complexes. 相似文献