共查询到18条相似文献,搜索用时 843 毫秒
1.
应用新型配体杯芳烃钕配合物与三异丁基铝以及添加Al(i-Bu) 2Cl为第三组分构成二元、三元均相催化体系催化丁二烯聚合.研究结果表明,对于杯[6,8]芳烃钕(C[n]Nd xCl y)/Al(i-Bu) 3/汽油体系,当n(Al)/n(Nd)=40~100,50℃时具有中等催化聚合活性,所制得聚丁二烯的粘均分子量为1×10 5~2×10 5,顺-1,4结构含量为89%左右,添加适量Al(i-Bu) 2Cl能提高催化活性.杯芳烃钕(C[n]Nd)构成的三元体系在n(Al)/n(Nd)=30,n(Cl)/n(Nd)=1~3时不同杯芳烃的活性次序为:C6>C4>C8 相似文献
2.
本文报导了MoCl 2(n-C 8H 17O) 2-(i-Bu) 2AlOph体系催化丁二烯聚合动力学研究结果,得到聚合速率方程式R=k(C) O(2)[M]=k pa(c) o(M),表观活化能18.6千卡/摩尔,指数前因子1.6×10 10分 -1,以及不同温度下的催化剂利用率,活性中心浓度,活性中心平均寿命等,还证明了等聚合速率的聚合时间t O与活性中心平均寿命相近。 相似文献
3.
用光谱法研究了异戊二烯顺-1,4聚合催化体系Ln(napb) 3-Al(i-C 4H 9) 3-Al 2(C 2H 5) 3Cl 3中稀土离子的价态.结果表明,在上述催化体系中,镨,钕,钆,铒部以三价形式存在,这说明上述稀土化合物催化活性的不同,不是因为价态有所差异.对不同条件下含Nd(naph) 3的催化剂溶液的光谱及聚合活性研究结果表明,催化活性与Nd +3的特征吸收强度有关,吸收强度愈强,活性愈高.提高铝/钕克分子比及延长催化剂陈化时间,都导致特征吸收强度及催化活性的增大. 相似文献
4.
双钼配合物〔Mo(DTC) 4〕〔MoCl 6〕(其中DTC=S 2CN(C 2H 5) 2)由于它在一个分子中同时包含两个处于不同配位环境中的、表观氧化态都是正五价的钼,即:一个Mo 5+与四个DTC配体构成配位阳离子〔Mo(DTC) 4〕 +;另一个Mo 5+与氯离子配体构成配位阴离子〔MoCl 6〕 -而独具特色。本文首次发表了它的红外和紫外-可见吸收光谱数据,并通过初步的光谱分析,确定了上述配合物的结构特征。 相似文献
5.
以MoCl 5和二乙胺基硫代甲酸钠为原料,在AlCl 3存在下于甲醇溶液中反应,生成双钼配合物Mo[S 2CN(C 2H 5) 2] +[MoCl 6]用循环伏安法研究了氧化还原特性。 相似文献
6.
β-二酮络合物已获得广泛而深入的研究,Ce(Ⅳ)的β-二酮类络合物的研究也有报导 [1-3].但是,关于Ce(Ⅳ)的β-二酮与其它混合配体络合物的研究至今未见报导.我们以(NH 4) 2Ce(NO 3) 6为起始物质,经由双-(三苯基氧化膦)硝酸铈(Ⅳ)中间络合物在混合溶剂中与DBM反应制得该化合物.通过紫外、红外光谱以及 1HNMR谱等研究,对该络合物的性质进行了讨论. 相似文献
7.
研究了新型高活性乙烯气相聚合催化剂TiCl 4/MgCl 2/ZnCl 2/SiCl 4/醇/Al(i-Bu) 3体系中钛和醇组分含量对聚合反应和产物颗粒形态的影响。测定了乙烯气相聚合反应动力学曲线,确定了聚合动力学方程。用SEM、DSC、WAXD、 13CNMR对催化剂及聚合物的形态、结构和性能进行了分析和表征。 相似文献
8.
对TiCl 3及TiCl 4/MgCl 2-Al(C 2H 5) 3(或Al(i-C 4H 9) 3、Al(C 2H 5) 2Cl)催化体系合成的聚辛烯的分子量分布用SchulzeFlory"最可几分布"函数作拟合处理,将各种聚合条件下的实测分布分成了3~5个"最可几分布"的叠加,催化剂结构及聚合条件对这些"最可几分布"峰的位置、大小的影响较有规律,表明每个峰对应于一种活性中心。还测定了聚辛烯各级分的活性中心浓度。对各活性中心的差异作了分析。 相似文献
9.
研究了新型高活性乙烯气相聚合催化剂TiCl 4/MgCl 2/ZnCl 2/SiCl 4/醇/Al(i-Bu) 3体系中不同醇、不同C 2H 5OH/Ti摩尔比和正丁醚对聚合反应及产物颗粒形态的影响。研究了预聚合反应及乙烯气相聚合反应规律。用扫描电镜和图象分析对催化剂、预聚物及聚合产物的形态和颗粒分布的研究结果表明:新型高活性催化剂和经预聚合制得的乙烯气相聚合物的颗粒形态类似球形,颗粒长短轴比值和大小粒径比值相近。 相似文献
10.
合成了3种不同结构的CnH 2n桥联双核茂钛配合物(CH 3) 2C[(C 5H 4)TiCl 2(C 5H 5)] 2(3),(CH 2) n[(C 5H 4)TiCl 2(C 5H 5)] 2(6,n=3;7,n=4),并用1HNMR进行了表征.发现以甲苯为溶剂时,不仅提高了产率,而且有效地避免了副产物Cp 2TiCl 2的生成.研究了化合物7/MAO(甲基铝氧烷)催化乙烯聚合的反应,考察了反应条件对催化体系的影响.结果表明,催化活性随着n(Al)/n(Cat.)比的增大而提高,聚乙烯的分子量在n(Al)/n(Cat.)=500和50℃时达到最高值9.0102×10 4;随着聚合时间的延长,催化活性下降,而产物分子量不断升高;随着温度的上升,50℃时催化活性和聚乙烯的分子量最高,分别为2.4074×10 5gPE/(molTi·h)和6.8679×10 4.随着桥联双核茂钛配合物碳桥的增长,催化活性增加,所得聚乙烯的分子量降低. 相似文献
11.
利用(μ 3-CCO 2Et)Co 3(CO) 9与单阴离子试剂[Mo(CO) 3(η 5-C 5H 4R)]-[R=H,C(O)Me]的反应合成了2个新的含CCo 2Mo骨架的簇合物(μ 3-CCO 2Et)Co 2Mo(CO) 8(η 5-C 5H 4R)[R=H(1);R=C(O)Me(2)],进而用其与双阴离子试剂{-M(CO) 3[η 5-C 5H 4C(O)]} 2-1,4-C 6H 4[M=Mo,W]反应合成了4个双四面体簇合物{(μ 3-CCO 2Et)CoMoM(CO) 7(η 5-C 5H 4R)[η 5-C 5H 4C(O)]} 2-1,4-C 6H 4[M=Mo,R=H(3);M=Mo,R=C(O)Me(4);M=W,R=H(5);M=W,R=C(O)Me(6)].这6个化合物的C和H元素分析,IR, 1HNMR等表征都与其结构一致.晶体X射线衍射分析表明,化合物2属单斜晶系,C 2/c空间群,晶胞参数a=1.1264(3)nm,b=1.1879(3)nm,c=3.3565(10)nm,β=93.320(5)°,V=4.484(2)nm 3,Z=8,D c=1.867g·cm -3,F(000)=2480,R=0.0369,wR=0.1150. 相似文献
12.
本文结合电化学测量和量子化学计算对Mo-Fe-S三元包合物的氧化还原特性进行了研究。用铂电极测得的该包合物在0.1MKClO 4-DMF溶液中的循环伏安图显现出两对氧化-还原峰,由此得到的电化学参数与EHMO计算结果都表明,电位较正的一对峰相应于Fe(Ⅲ)/Fe(Ⅱ)的氧化还原,反应不可逆。电位较负的一对峰相应于Mo(Ⅴ)/Mo(Ⅳ)的氧化还原反应半可逆。 相似文献
13.
LnCl 3 (Ln=Nd, Gd) reacts with C 5H 9C 5H 4Na (or K 2C 8H 8) in THF (C 5H 9C 5H 4 = cyclopentylcyclopentadienyl) in the ratio of 1 : to give (C 5H 9C 5H 4)LnCl 2(THF) n (orC 8H 8)LnCl 2(THF) n], which further reacts with K 2C 8H 8 (or C 5H 9C 5H 4Na) in THF to form the litle complexes. If Ln=Nd the complex (C 8H 8)Nd(C 5H 9C 5H 4)(THF) 2 (a) was obtained: when Ln=Gd the 1 : 1 complex [(C 8H 8)Gd(C %H 9)(THF)][(C 8H 8)Gd(C 5H 9H 4)(THF) 2] (b) was obtained in crystalline form. The crystal structure analysis shows that in (C8H8)Ln(C5H9C5H4)(THF)2 (Ln=Nd or Gd), the Cyclopentylcyclopentadieny (η5), cyclooctatetraenyl (η8) and two oxygen atoms from THF are coordinated to Nd3+ (or Gd3+) with coordination number 10. The centroid of the cyclopentadienyl ring (Cp′) in C5H9C5H4 group, cyclooctatetraenyl centroid (COTL) and two oxygens (THF) form a twisted tetrahedron around Nd3+ (or Gd3+). In (C8H8)Gd(C5H9C5H4)(THF), the cyclopentyl-cyclopentadienyl (η5), cyclooctatetraenyl (η8) and one oxygen atom are coordinated to Gd3+ with the coordination number of 9 and Cp′, COT and oxygen atom form a triangular plane around Gd3+, which is almost in the plane (dev. -0.0144 Å). 相似文献
14.
The new diphenolato complexes [{Mo(NO){HB(dmpz) 3}Cl} 2Q] where dmpz = 3,5-dimethylpyrazolyl and Q = OC 6H 4(C 6H 4O ( n = 1 or 2), OC 6H 4CR=CRC 6H 4O (R = H or Et), and OC 6H 4CH=CHC 6H 4CH=CHC 6H 4O have been prepared and their electrochemical properties (cyclic and differential pulse voltammetry) compared with previously reported analogues where Q = OC 6H 4O, OC 6H 4EC 6H 4O (E = SO 2, CO and S), OC 6H 4 (CO)C 6H 4 C 6H 4(CO)C 6H 4O and 1,5- and 2,7-O 2C 10H 6. The electrochemical interaction between the redox centres in the new complexes is very weak, in contrast to that in the 1,4-benzenediolato and naphthalendiolato species. The EPR spectra of the reduced mixed-valence species [{Mo(NO){HB(dmpz) 3}Cl} 2Q] − where Q = 1,3- and 1,4-OC 6H 4O and OC 6H 4SC 6H 4O shows that they are valence-trapped at room temperature, whereas those of the dianions [{Mo(NO){HB(dmpz) 3}Cl} 2Q] 2− where Q = 1,4-OC 6H 4O, OC 6H 4EC 6H 4O (E = CO or S) and OC 6H 4CH=CHC 6H 4CH=CHC 6H 4O shows that the unpaired spins on each molybdenum centre are strongly correlated ( J, the spin exchange integral A Mo, the metal-hyperfine coupling constant). The electrochemical properties and the comproportionation constants for the reaction [{Mo(NO){HB(dmpz) 3} Cl} 2Q] + [{Mo(NO){HB(dmpz) 3}Cl}O] 2] 2−2[{Mo(NO) {HB(dmpz) 3}Cl} 2Q] − where Q = diphenolato bridge, are compared with related compounds containing benzenediamido and dianilido bridges. 相似文献
15.
The coordinatively unsaturated uranium(IV) complex U[N(C 6H 5) 2] 4 has been prepared via the stoichiometric reaction of diphenylamine with [(Me 3Si) 2N] 2
H 2. U[N(C 6H 5) 2] 4 coordinates Lewis bases such as Et 2O, THF, pyridine or (EtO) 3PO, based on electronic absorption spectroscopy and 1H NMR studies. Exchange between U[N(C 6H 5) 2] 4 and U[N(C 6H 5) 2] 4(L), where L is THF or pyridine, is rapid on the NMR time-scale between 307 and 323 K. Measurement of equilibrium constants for L = THF provides Δ H and Δ S values of −60 kJ mol −1 and −1.8 × 10 2 J K −1 mol −1, respectively. U[N(C 6H 5) 2] 4 coordinates and binds (EtO) 3PO much more tightly ( Keq = & > 10 4 M −1) than THF or pyridine with the exchange rate between U[N(C 6H 5) 2] 4 and U[N(C 6H 5) 2] 4[OP(OEt) 3] being close to the NMR time-scale. 相似文献
16.
A coincidence technique is used to study the influence of the internal energy of the reactant ion on the cross section of the ion-molecule reactions in the C 2H 4+ + C 2H 4 system. The experiment is performed at thermal collision energies. In the ion-molecule reactions of C 2H 4+ + C 2H 4 our measurements indicate a barrier between the initially formed collision complex (C 2H 4) 2+* and a tight complex (C 4H 8+)*. Using an extension of our earlier developed statistical model, now including a potential barrier between the initially formed loose complex (C 2H 4) 2+* and the tight complex (C 4H 8+)*, our experimental data can be reproduced. For comparison also the internal energy dependence of the unimolecular decomposition of photoionised 1-C 4H 8+ is measured. Assuming that the photoionised 1-C 4H 8+ is identical with the tight (C 4H 8+)* complex, the model applied to the ion-molecule reactions describes also the unimolecular decay of 1-C 4H 8+ correctly, using the same set of parameters. 相似文献
17.
The thermogravimetric behaviour of UO 2(C 9H 6NO) 2.C 9H 6NOH and [UO 2(C 9H 6NO) 2] 2.C 9H 6NOH prepared by precipitation from homogeneous solution with 8-acetoxy-quinoline has been found to closely resemble that of UO 2(C 9H 6NO) 2.C 9H 6NOH prepared by direct precipitation of uranium VI with 8-hydroxyquinoline. 相似文献
18.
利用Co 2(CO) 8与[Cl 3CC(O)OCH 2] 2的反应合成了以C(O)OCH 2CH 2OC(O)桥联两个Co 3C四面体骨架为特征的新型双四面体簇合物[(CO) 9Co 3(μ 3-C)C(O)OCH 2] 2(1);1与不同物质的量比的Na[M(CO) 3C 5H 4R](M=Mo,W;R=H,C(O)Me)反应,得到一步交换的产物(CO) 9Co 3(μ 3-C)C(O)OCH 2CH 2OC(O)(μ 3-C)Co 2M(CO) 8(C 5H 4R)[M=Mo,R=H(2);M=Mo,R=C(O)Me(3);M=W,R=H(4);M=W,R=C(O)Me(5)]或两步交换的产物[(C 5H 4R)(CO) 8Co 2M(μ 3-C)C(O)OCH 2] 2[M=Mo,R=H(6);M=Mo,R=C(O)Me(7);M=W,R=H(8);M=W,R=C(O)Me(9)].5或9分别与Na[Mo(CO) 3C 5H 5]以12的物质的量比反应得到含一个手性四面体骨架(CoMoWC)的(C 5H 5)(CO) 8Co 2Mo(μ 3-C)C(O)OCH 2CH 2O·C(O)(μ 3-C)CoMoW(CO) 7(C 5H 4C(O)Me)(C 5H 5)(10)或含两个手性四面体骨架(CoMoWC)的[(C 5H 5)(C 5H 4C(O)Me)(CO) 7CoMoW(μ 3-C)C(O)OCH 2] 2(11);对化合物1_11进行了CH元素分析、IR和 1HNMR等表征.结果表明,在金属交换反应中处于不同簇环境下的Co(CO) 3基团反应活性不同.对化合物1进行了晶体X射线衍射分析.化合物1的晶体属单斜晶系,P2 1/n(#14)空间群,晶胞参数a=0.933 0(2)nm,b=1.519 7(4)nm,c=1.178 3(4)nm,=91.16(2)°,Z=2,F(000)=972.分子结构呈中心对称. 相似文献
|