Polymer-supported organometallic compounds of titanium,zirconium and hafnium as hydrogenation catalysts

Cyclopentadienyl compounds of titanium, zirconium and hafnium have been prepared attached to polymers by first binding cyclopentadiene to styrene-divinylbenzene (20%) copolymers and then converting them to cyclopentadienyl anions. The resin-bound anions were treated with MCl_n and polymer-attached Mcl_n?1 compounds were formed (where M = Ti, Zr and Hf). The polymer-attached monocyclopentadienyl titanium trichloride on reduction with butyl lithium produces active catalysts whose hydrogenation efficiencies are 10 to 20 times as great as the corresponding non-attached species under the same conditions. Studies of the physical nature of the metal catalyst dispersions on the polymer supports by using an electron-X-ray fluorescence microprobe indicate that the dispersion is uniform throughout the entire section of the bead.     

Mixed ligand platinum complexes as hydrogenation catalysts

PtLL′Cl₂ (L = PPh₃, L′ = sulphides, amines) are more effective catalysts for the hydrogenation of styrene to ethylbenzene, in the presence of SnCl₂·2H₂O than PtL₂Cl₂ or PtL′₂Cl₂; this effect is attributed to the ability of the weaker ligand L′ to function as a leaving group in the catalytic hydrogenation cycle.     

Copolymerization of 2‐butene and ethylene with catalysts based on titanium and zirconium complexes

The polymerization of 2‐butene and its copolymerization with ethylene have been investigated using four kinds of dichlorobis(β‐diketonato)titanium complexes, [ArN(CH₂)₃NAr]TiCl₂ (Ar = 2,6‐ⁱPr₂C₆H₃) and typical metallocene catalysts. The obtained copolymers display lower melting points than those produced of homopolyethylene under the same polymerization conditions. ¹³C NMR analysis indicates that 9.3 mol‐% of 2‐butene units were incorporated into the polymer chains with Ti(BFA)₂Cl₂‐MAO as the catalyst system. With the trans‐2‐butene a higher copolymerization rate was observed than with cis‐2‐butene. A highly regioselective catalyst system for propene polymerization, [ArN(CH₂)₃NAr]TiCl₂ complex using a mixture of triisobutylaluminium and Ph₃CB(C₆F₅)₄ as cocatalyst, was found to copolymerize a mixture of 1‐butene and trans‐2‐butene with ethylene up to 3.1 mol‐%. Monomer isomerization‐polymerization proceeds with typical metallocene catalysts to produce copolymers consisting of ethylene and 1‐butene.     

Asymmetric hydrogenation of imines and olefins using phosphine-oxazoline iridium complexes as catalysts

Herein we describe the synthesis of a new class of chiral phosphine-oxazolines and their application as ligands in iridium-catalyzed hydrogenations. Mechanistic aspects of olefin hydrogenation with this class of iridium catalysts are discussed and a selectivity model to help rationalize the results obtained is also presented.     

高活性Cu/SiO2催化剂应用于丙二酸二乙酯加氢制1,3-丙二醇

作为聚对苯二甲酸丙二醇酯(PTT)的不可替代原料,1,3-丙二醇(1,3-PDO)广泛应用于聚酯、树脂、化妆品、润滑剂和制冷剂等领域.采用丙二酸二乙酯(DEM)一步加氢合成1,3-PDO可避免传统化学工艺中醛类副产物的生成和生物法中产品纯度不高的问题,进而满足下游PTT的品质要求. Cu/SiO2催化剂因铜与载体间的强相互作用以及硅胶的弱酸性有利于催化活性中心的建立而被广泛应用于气相加氢反应,可以选择性地活化C?O键而不活化C?C键.因此,本文将Cu/SiO2催化剂应用于DEM加氢反应,重点考察了焙烧温度对催化剂结构与性能影响的本质原因.
　　采用蒸氨法制备Cu/SiO2催化剂,将一定量氨水滴加到硝酸铜水溶液中形成铜氨溶液后滴加JN-30硅溶胶,经老化、过滤、洗涤、烘干、焙烧、压片成型后得到40?60目的催化剂.将不同温度(623?1023 K)焙烧的Cu/SiO2催化剂装填入自制连续高压固定床反应器中进行DEM加氢反应,并采用N2物理吸脱附、电感耦合等离子体发射光谱、N2O化学吸附、X射线衍射、傅里叶红外光谱、H2程序升温还原(TPR)、透射电镜及X射线光电子能谱等手段对不同温度焙烧催化剂进行表征.结果表明,在723 K焙烧的催化剂具有最大的比表面积和最均一的孔径分布,其铜组分分散均匀,活性铜表面积最大,焙烧后可以形成最多的页硅酸铜,导致还原后Cu+/Cu0比例较高.在该催化剂作用下,于473 K、2.0 MPa、氢酯摩尔比330和液体空速1.8 h–1条件下, DEM转化率为90.7%,1,3-PDO选择性为32.3%.
　　焙烧温度对Cu/SiO2催化剂组成、织构、结构、形貌及还原后的价态有较大影响.在焙烧温度为623?1023 K时,低温焙烧有利于生成页硅酸铜,而高温焙烧则有利于形成CuO.在焙烧温度升高的过程中,铜组分形态会发生较大变化,在623?723 K焙烧的催化剂中页硅酸铜含量不断增加;继续升高温度至823 K,页硅酸铜含量减少,但是分散变差,导致铜的比表面积、孔体积和孔径最小;进一步升高温度至923 K,页硅酸铜消失, CuO分散均匀, H2-TPR的还原峰窄且对称;当温度升高到1023 K时,铜晶体迅速长大而较难被还原.     

Ethylene oligomerization on heterogenized titanium and zirconium complexes

Besides other products, linear middle-range olefins were obtained in the low temperature oligomerization of ethylene with a selectivity of 30–58% and a linearity up to 85%. Activated ticanium and zirconium complexes as catalysts were attached to SiO₂ through surface bounded bidentate S- and N-containing ligands, the former being superior to the latter with respect to product quality.

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30–58 .% 85%. - - , , SiO₂ S- N- . , , .

     

Rhodium complexes with dioximes as catalysts of hydroformylation and hydrogenation of 1-hexene

Rhodium(II) complexes with dioximes [Rh(Hdmg)₂(PPh₃)]₂ [I] (Hdmg=monoanion of dimethylglyoxime) and [Rh(Hdmg)(ClZndmg)(PPh₃)]₂ [II] catalyse hydroformylation and hydrogenation reactions of 1-hexene at 1 MPa CO/H₂ and 0.5 MPa H₂ at 353 K, respectively. Hydroformylation with complex [I] produces 94% of aldehydes (n/iso=2.2) and 6% 2-hexene whereas the second catalyst [II] gives ca. 40% of aldehydes (n/iso=2.1) and 60% of 2-hexene. Corresponding Rh(III) complexes are inactive in hydroformylation except of RhH(Hdmg)₂(PPh₃) [III], which shows activity similar to [I]. Complexes [Rh(Hdmg)₂(PPh₃)]₂ [I], [Rh(Hdmg)(ClZndmg)(PPh₃)]₂ [II], RhH(Hdmg)₂(PPh₃) [III] and [Rh(Hdmg)₂(PPh₃)₂]ClO₄ [V] catalyse 1-hexene hydrogenation with an average TON ca. 18 cycles/mol [Rh]×min. Complex [II] has also been found to catalyse hydrogenation of cyclohexene, 1,3-cyclohexadiene and styrene.     

Studies of the composition and catalytic properties of supported catalysts prepared through halide-substituted titanium and zirconium benzyl complexes

Composition and catalytic properties in ethylene polymerization of supported systems prepared via the interaction of Ti(CH₂C₆H₅)₃X (X=F, Cl, Br) and Zr(CH₂C₆H₅)₂Cl₂ complexes with silica and alumina have been studied. Halide addition to benzyl complexes decreases the polymer molecular mass.

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, Ti(CH₂C₆H₅)₃X (X=F, Cl, Br) Zr(CH₂C₆H₅)₂Cl₂ SiO₂ Al₂O₃. , .

     

N2 hydrogenation from activated end-on bis(indenyl) zirconium dinitrogen complexes

Sodium amalgam reduction of the bis(indenyl)zirconium dihalide complexes, (eta5-C9H5-1-iPr-3-Me)2ZrX2 (X = Cl, Br, I), yielded the corresponding end-on dinitrogen complexes, [(eta5-C9H5-1-iPr-3-Me)2Zr(NaX)]2(mu2, eta1, eta1-N2), with inclusion of 1 equiv of salt per zirconocene. The solid state structures of the chloro and iodo congeners establish short Zr N and elongated N N bonds, consistent with modest to strong activation of the coordinated dinitrogen molecule. Exposure of the N2 compounds to 1 atm of dihydrogen resulted in rapid N H bond formation to yield a hydrido zirconocene hydrazido compound concomitant with salt elimination. These studies establish a new structural type of zirconocene dinitrogen complex and demonstrate that side-on coordination of the N2 ligand in the ground state is not a prerequisite for dinitrogen hydrogenation.     

Polystyrene anchored rhodium (I) bidentate ligand complexes as catalysts for hydrogenation

Polystyrene supported Rh(I) AA′ (AA′ = anthranilic acid, 2,2′-bipyridine or 1,10-phenanthroline) complexes catalyse the hydrogenation of monoolefins (terminal, cyclic and internal) and dienes. Ethyl sorbate undergoes saturation via the monoene intermediate. Thiscis olefin reacts faster than thetrans isomer. The rate law for the reaction is: Rate α [catalyst] [substrate] [H₂].     

醇预处理载体制备的 Ir-Re/SiO2催化剂上甘油氢解反应

甘油是生物柴油的副产物,将其转化为高附加值的化学品,能提高生物柴油产业的经济性.1,3-丙二醇是聚酯和聚氨酯的单体,也用于合成医药和用作有机合成中间体,甘油直接催化氢解反应制1,3-丙二醇极具发展潜力.另外,甘油是生物质转化的重要平台分子之一,与目标产物的分子结构相比较,生物质平台分子通常含有过多的含氧基团,尤其是多余的羟基,通过甘油氢解反应研究多羟基的选择性活化和脱除,可以加深对生物质脱氧规律的认识.因此,研究甘油氢解反应制1,3-丙二醇催化剂和工艺,不仅具有潜在的应用前景,而且具有重要理论价值.然而,目前的甘油氢解催化剂性能还不够高,我们希望通过一些表面改性的方法处理载体硅胶,从而改变金属前驱体与载体表面的作用.因此,本文使用 C1–C4的正构醇处理硅胶载体,其负载的 Ir-Re催化剂上甘油氢解反应转化率从42.7%提高到59.5%,仲羟基脱除收率从21.6%提高到28.3%.研究发现,当处理载体所用正构醇的碳数从1增加到3时,对应催化剂上甘油转化率逐渐增加至最高;但当使用更正丁醇时,对应催化剂上甘油转化率下降.为了探究催化剂活性改变的原因,我们首先采用红外光谱(FT-IR)和氮气物理吸附确定烷氧基基团嫁接到硅胶载体上.程序升温还原结果发现,预处理载体相应的催化剂开始还原温度降低,表明在这些催化剂上形成了颗粒尺寸较小的Ir粒子. X-射线衍射分析发现,在新鲜的和使用后的催化剂上均未检测出Re物种的衍射峰,说明Re高度分散于催化剂表面.吸附吡啶的FT-IR结果表明,未处理和丙醇预处理硅胶负载的催化剂上均没有强酸位,它们的B/L酸比值相近,约为3.3.催化剂的吸附COFT-IR结果表明, CO线性吸附于Ir/SiO2催化剂上的主要吸收峰位置在2084 cm–1;而Re的加入使得该吸收峰红移,表明Ir和ReOx物种之间存在相互作用.透射电镜(TEM)、H2-程序升温脱附和NH3-程序升温脱附结果发现,醇预处理催化剂上具有更多的Ir-ReOx界面,而界面位点的数量与甘油转化率大小一致,表明Ir-ReOx位点可能就是甘油氢解的活性中心.反应后催化剂的TEM结果表明,醇预处理催化剂上的Ir颗粒要小于未处理催化剂的,其中丙醇预处理硅胶负载的催化剂上Ir粒径最小.这是由于醇处理催化剂上存在很多孤立的Si–OH,它们与金属前驱体相互作用有利于形成较小的金属颗粒.这些孤立的Si-OH则是由于表面烷氧基基团的隔离作用所形成的.当处理载体所用正构醇的碳数从1增加到3时,烷氧基的碳链变长,分隔作用越好,阻止金属前驱体聚集的程度越强,因而Ir物种和Re物种的分散度增加.但是当处理醇的碳数增加到4时,形成的表面烷氧基基团可能阻止了Re物种和Ir物种间相互作用,从而使得Ir和Re物种的分散度均降低,相应催化剂活性随之降低.     

Heterobimetallic diethanolaminate complexes of titanium and zirconium with alkaline earth metals

Ti(OPr ⁱ )₄ or Zr(OPr ⁱ )₄ · Pr ⁱ OH react with hydrocarbon-insoluble complexes M{(OCH₂CH₂)NH(CH₂CH₂OH)}₂ (M = Mg, Ca, Sr, Ba) in a 2:1 molar ratio to yield hydrocarbon-soluble heterobimetallic diethanolaminate isopropoxide complexes [M{(OCH₂CH₂)₂NH}₂{M(OPr ⁱ )₃}₂] (M = Mg, Ca, Sr, Ba; M = Ti, Zr), which have been characterized by elemental analyses, molecular weight measurements and spectroscopic [i.r., n.m.r. (¹H and ¹³C)] studies.     

Cationic palladium(II) complexes of ferrocenylphosphines as homogeneous hydrogenation catalysts for olefins

Cationic palladium(II) complexes of ferrocenylphosphines [(L-L′)Pd(S)₂][ClO₄]₂ ((L-L′) = Fe(η⁵-C₅H₄P (C₆H₅)₂)₂ 1, or Fe(η⁵-C₅H₅)(η⁵C₅H₃(CHMeNMe₂)P(C₆H₅)₂-1,2) 2a: S=pyridine or dimethylformamide) were prepared and characterized. The derivatives of 2a are effective catalysts for the hydrogenation of simple olefins at 30°C (1 atm H₂). The rate of reduction of styrene depends on the substrate concentration, catalyst concentration and the solvent, and is only slightly inhibited (16%) by the addition of mercury. These observations are conistent with a homogeneous catalytic system.     

手性钛锆化合物在不对称合成中的应用

本文综述了近年来手性钛锆化合物在不对称合成中的应用, 特别是手性柄型金属钛和锆化合物在不对称合成中的应用。对这类催化剂的特点和前景作了简要介绍。     

Carbalumination of higher α-olefins catalyzed by titanium and zirconium complexes

Conclusions A regioselective method was developed for the carbometallation of higher-olefins using Et₃Al and Et₂AlCl in the presence of titanium and zirconium complexes which permits the preparation of higher trialkylaluminums and dialkylaluminum halides in high yield under mild conditions in one step.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 1, pp. 207–209, January, 1985.     

Deactivation pathways of ethylene polymerization catalysts derived from titanium and zirconium 1,3-bis(furyl)-1,1,3,3-tetramethyldisilazide complexes

The stoichiometric reaction between the previously described lithium amide salts, LiN(SiMe2R)2 [Li{i}, R = furyl, Li{ii}, R = 2-methylfuryl] and titanium(iv)chloride at low temperature afforded the mono-amide compounds Ti{i}Cl3 (1a) and Ti{ii}Cl3 (1b). The analogous zirconium derivatives Zr{i}Cl3 (3a) and Zr{ii}Cl3 (3b) were accessed via the reaction of excess trimethylsilylchloride with the mixed tetra-amide species, Zr{i}(NMe2)3 (2a) and Zr{ii}(NMe2)3 (2b). The bis-amide complexes Ti{ii}2Cl2 (4b), Zr{i}2Cl2 (5a) and Zr{ii}2Cl2 (5b) were synthesized in a straightforward salt metathesis reaction employing two equivalents of Li{i} or Li{ii} with the metal salts, MCl4(THF)2. The reactivity of the halide compounds 1 and 3-5 with a variety of alkylating agents was studied, with ligand transfer from the transition-element to the main group metal-alkyl reagent being the predominant reaction pathway. The reaction of 4b with MeLi was, however, partially successful affording the titanium(III) complex, Ti{ii}2X (X = Cl/Me, 6b'); this compound was subsequently made as the pure chloride from the reaction of two equivalents of Li{iii} with TiCl3(THF)3. The targeted dialkyl species, Ti{ii}Me2 (7b), was successfully isolated from the reaction between the dichloride 4b and dimethylmagnesium. The molecular structures of 1a, 1b, [3a]2 [3b]2, 4b, 5b and 6b have been solved using single-crystal X-ray diffraction techniques, indicating varying nuclearity of the complexes and hapticities for the amide ligands in the solid-state. The catalytic activity of selected complexes in the polymerization of ethylene is reported.