铼基催化剂上乙烯与高碳内烯烃歧化制α-烯烃

在固定床反应器上考察了不同载体的9%Re2O7/Al2O3催化剂在乙烯与高碳内烯烃歧化反应中的催化性能,同时通过XRD、NH3-TPD、N2吸附、TG-DTG对催化剂进行了表征。实验结果表明,氧化铝载体的比表面积和酸性的增加可以提高高碳内烯烃的转化率和选择性,催化剂失活的主要原因可能是积碳引起的酸量下降。在60℃、3.0 MPa、C12烯烃/C11烯烃摩尔比为1.5和混合高碳内烯烃LHSV=1.0 h-1的反应条件下,9%Re2O7/ZB-Al2O3上的高碳内烯烃转化率达到82.23%,选择性达到92.66%。     

不同氧化铝载体对丁烯自歧化反应性能的影响

在固定床反应器上考察了不同氧化铝载体的9％ Re2O2/Al2O3催化剂在混合丁烯自歧化反应中的催化性能,同时通过XRD、NH3-TPD和N２吸附对催化剂进行了表征.实验结果表明,氧化铝载体的比表面积和酸强度的增加可以提高2-丁烯的转化率和丙烯/乙烯选择性.在60℃、1.0 MPa、1-丁烯/2-丁烯摩尔比为3和混合丁烯WHSV=1.2 h-1的反应条件下,9％ Re207/ZB-Al2O3上的2-丁烯转化率达到82.15％,丙烯/乙烯选择性达到80.53％.     

松香歧化催化剂的研究进展

综述了本世纪中叶以来用于松香歧化反应催化剂的研究及工业应用情况,对各种催化剂的优缺点了评价和比较。     

烯烃歧化反应中的负载氧化钨催化剂

综述了负载型钨基催化剂用于烯烃歧化领域的研究情况,着重介绍了负载氧化钨催化剂的制备、反应机理和工艺条件的研究,简要介绍了负载有机钨催化剂的研究进展。在此基础上,文章总结了影响负载氧化钨催化剂活性的几个重要因素,如中心金属（钨）的价态、金属中心的构型、催化剂的酸性以及负载金属的分散性等,并提出了负载型钨基歧化催化剂的研究趋势,希望能对以后开发高活性的氧化钨催化剂提供有益的指导和参考依据。     

Re含量对Re-Mo催化剂上丁烯自歧化反应的影响

采用等体积浸渍法制备了3%MoO3-x%Re2O7/γ-Al2O3(负载量均为质量分数,下同)双金属催化剂(x=0¹),以混合丁烯〔n(1-丁烯)/n(2-丁烯)=3〕为原料,在固定床反应器上考察了不同Re含量对Re-Mo双金属催化剂在丁烯自歧化反应中的催化性能,并采用XRD、NH3-TPD、H2-TPR和N2物理吸附对催化剂进行了表征。结果表明,与3%MoO3/γ-Al2O3催化剂相比,双金属催化剂增加了催化剂的酸量,抑制了在反应初期的"诱导期",提高了催化剂在丁烯自歧化反应中的活性和稳定性。在80℃、1.0 MPa、混合丁烯WHSV=1.2 h-1的条件下,3%MoO3-1%Re2O7/Al2O3催化剂(Re2O7负载量1%,MoO3负载量3%)上丁烯自歧化反应在70 h内可维持60%以上的丁烯转化率和约25%的丙烯收率。     

松香歧化催化剂的研究进展

综述了本世纪中叶以来用于松香歧化反应催化剂的研究及工业应用情况,对各种催化剂的优缺点做了评价和比较     

甲苯歧化工艺及催化剂研究进展

概述甲苯歧化及Ｃ９芳烃烷基转移技术,以及β沸石,ＭＣＭ－２２,Ω等新型催化材料在甲苯歧化及Ｃ９芳烃烷基转移反应中的研究进展及甲苯选择性歧化工艺及改地ＺＳＭ－５催化剂研究动态。     

烯烃歧化技术在增产丙烯方面的工艺进展

当前,全球丙烯需求持续快速增长,在利用传统的蒸气裂解、催化裂化、丙烷脱氢等工艺生产丙烯的同时,深入研发了4种新型增产丙烯的工艺。其中烯烃歧化反应工艺因其适应国情、投资成本较低、操作灵活而得到更广泛的关注,其核心催化剂体系的研发经历了多组分非均相、多组分均相催化体系、单组分均相催化体系几个阶段。以钌系金属卡宾配合物为代表的新型催化剂体系,具有快速引发、高活性、高选择性等特点,显示出良好的应用前景。     

钼基催化剂在烯烃液相环氧化反应中的应用研究进展

介绍了钼络合物催化剂、固载化的钼络合物催化剂及MoO₃基的固体钼催化剂在烯烃液相环氧化反应中的应用。以有机过氧化物为氧化剂时,不同的钼基催化剂均表现出很好的催化性能,其中络合物中的配体对其催化性能有很大影响,并且可以通过引入手性配体实现对烯烃的不对称环氧化,而固体钼催化剂的性能则与载体上钼物种的种类密切相关。但绝大多数钼催化剂对H₂O₂参与的环氧化反应没有活性,开发对H₂O₂有催化活性的钼基催化剂是一个重要的研究方向。     

国产钨基催化剂在烯烃歧化制丙烯工业侧线装置上的性能研究

针对丁烯和乙烯歧化增产丙烯技术(OCT技术)所用进口BASF催化剂价格昂贵、运输条件苛刻等情况,自主研发了钨基歧化催化剂,并在实验室小试装置和OCT工业侧线固定床反应器上,考察了该催化剂在OCT技术制备丙烯过程中的催化性能。结果表明,1-丁烯的异构化率和丙烯的选择性均随反应温度的升高和乙烯、丁烯摩尔比的增加而逐渐增加,自主研发催化剂的催化活性和进口催化剂相当,且催化剂稳定性良好,可连续运行400 h以上。     

Technological and economical aspects of the metathesis of unsaturated esters

The metathesis of alkenes is a well-established reaction that is applied in various commercial processes. The meta-thesis of functionalized olefins has not yet been commercialized despite its considerable potential. The conversion of oleochemical feedstocks into specialty chemicals appears especially attractive. In this paper, a process scheme is proposed for the production of 1,18-dimethyl octadecanedioate from pure methyl oleate by metathesis. The chemical and technological bottlenecks are explored, and a rough economic evaluation of this route is given. From these considerations, it is concluded that such a process for the metathesis of functionalized alkenes could be viable only if certain conditions are met. Rapid catalyst deactivation is identified as one of the main obstacles. Feedstock purity, efficient recycling of unreacted feed and multiple catalyst regeneration are crucial for economic feasibility. Rhenium-based catalysts are to be preferred over molybdenum ones because their activation is easier and regenerability is superior. Finally, the direction for future technological and catalysis research is given based upon the results of this work.     

Alkyne Metatheses in Transition Metal Coordination Spheres: Convenient Tungsten‐ and Molybdenum‐Catalyzed Syntheses of Novel Metallamacrocycles

Reactions of (CO)₅Re(Br), (η⁵‐C₅H₅)Ru(Cl)(PPh₃)₂, and [Pt(μ‐Cl)(C₆F₅)(S(CH₂CH₂‐)₂)]₂ with the alkyne‐containing phosphine Ph₂P(CH₂)₆C≡CCH₃ give the bis(phosphine) complexes fac‐(CO)₃Re(Br)(Ph₂P(CH₂)₆C≡CCH₃)₂ ( 5 ), (η⁵‐C₅H₅)Ru(Cl)(Ph₂P(CH₂)₆C≡CCH₃)₂ ( 6 ), and trans‐(Cl)(C₆F₅)Pt(Ph₂P(CH₂)₆C≡CCH₃)₂ ( 7 ). Alkyne metatheses with the catalyst (t‐BuO)₃W(≡C‐t‐Bu) (10–15 mol %, chlorobenzene, 80 °C) give the seventeen‐membered metallamacrocycles fac‐(CO)₃Re(Br)(Ph₂P(CH₂)₆CC(CH₂)₆P Ph₂) ( 8 ), (η⁵‐C₅H₅)Ru(Cl)(Ph₂P(CH₂)₆CC(CH₂)₆P Ph₂) ( 9 ), and trans‐(Cl)(C₆F₅)Pt(PPh₂(CH₂)₆CC(CH₂)₆P Ph₂) ( 10 ). ³¹P NMR analyses show 90–75% conversions to 8 – 10 (59–47% isolated after chromatography). The identity of 8 was confirmed by a crystal structure, and 10 was hydrogenated over Pd/C to fac‐(CO)₃Re(Br)(Ph₂P(CH₂)₆CC(CH₂)₆P Ph₂) ( 12 , 87%), which was crystallographically characterized earlier. A catalyst derived from Mo(CO)₆/4‐chlorophenol effects a slower conversion of 7 to 10 at 140 °C. In the case of 5 , a mer, trans isomer of 8 is isolated ( 11 , 44%), as established by NMR and IR data. In 10 – 12 , the diphosphines span trans positions. These results, together with previous examples involving group VIII metallocenes, establish the wide viability of the title reaction.     

Acyclic metathesis during ring-opening metathesis polymerization of cyclopentene

‘Living’ ring-opening metathesis polymerization (ROMP) permits the synthesis of narrow-distribution homopolymers and well-defined block copolymers - provided no side reactions occur. However, acyclic metathesis between the chain end and double bonds in the polymer backbone competes with propagation during ROMP of cyclopentene, even with a mild Mo catalyst, though the rate constant is some 1600-fold smaller. ‘Dead’ chains in the reaction mixture can also be attacked; the products of acyclic metathesis are tagged by quenching the ROMP reaction with pyrenecarboxaldehyde. The extent of acyclic metathesis can be minimized through proper choice of reaction conditions, permitting the synthesis of narrow-distribution polycyclopentene with 100 kg/mol molecular weight.     

Ring-Opening Metathesis Polymerization of 5,6-Bis(Chloromethyl)-Norbornene by Tungsten(II) and Molybdenum(II) Complexes

The reaction of endo,endo-5,6-bis(chloromethyl)bicyclo[2.2.1]hept-2-ene in the presence of seven-coordinate tungsten(II) and molybdenum(II) complexes of the type [MCl(M'Cl₃)(CO)₃(NCMe)₂] (M'=W, Mo; M=Sn, Ge) leads to ring-opening metathesis polymerization and to the formation of high-molecular-weight soluble polymers with dispersity index in the range 1.4-2.0 and number average molecular weights in the range 300 000-790 000 g mol^-1. The geometric structure of these polymers was determined by means of ¹H- and ¹³C-NMR spectroscopy. Molybdenum catalysts gave polymers with lower cis vinylene content (20-50%), whereas tungsten catalysts gave polymers with higher cis vinylene content (84-95%).     

MgO在WO3/SiO2催化烯烃歧化反应中的作用

综述了负载型钨基催化剂用于烯烃歧化领域的研究情况,简要介绍了烯烃歧化催化剂的研究进展以及歧化反应机理,着重介绍了Mg O助剂在WO3/Si O2催化的丙烯歧化反应中的作用,如生成活性的气相激发物种、促进1-丁烯异构成2-丁烯、调节酸性以减少副反应以及吸附毒物净化原料等,并对Mg O在歧化体系中的作用机理问题进行了部分探讨。此外,还提出了共催化体系的研究趋势,希望能对以后开发高活性的Mg O-WO3/Si O2共催化体系提供有益的指导和参考依据。     

从废旧高温合金的硫酸浸出渣中浸出分离钨钼铼

对废旧高温合金硫酸浸出残渣选择HCl-FeCl3-H2O2体系氧化浸出、浸出后加入NaOH调节溶液pH值,使钨、钼、铼与铌、钽等分离,研究了反应时间、反应温度、HCl用量、FeCl3用量、H2O2用量对钨、钼、铼浸出率的影响. 结果表明,该体系能充分浸出渣中钨、钼、铼3种金属,添加FeCl3可提高钼在盐酸溶液中的浸出率. 在浸出温度70℃、浸出时间5 h、FeCl3用量100 g/L、H2O2用量10 mL/g及HCl初始用量10 mL/g的条件下,钨、钼、铼浸出率分别大于97%, 86%, 91%.     

Alumina supported tungsten hydrides, new efficient catalysts for alkane metathesis

Silica and alumina supported tantalum and tungsten hydrides were tested in alkane metathesis, for comparison of their catalytic properties. In propane metathesis [W]–H/Al₂O₃ proves to be twice more efficient than the usual [Ta]–H/SiO₂ catalyst which is still better than [Ta]–H/Al₂O₃ and [W]–H/SiO₂. Tungsten based catalysts lead to a narrower distribution in the products selectivity and to a higher amount of linear products than [Ta]–H/SiO₂. [W]–H/Al₂O₃ is also a better catalyst than [Ta]–H/SiO₂ for butane metathesis but is less efficient with ethane. Whereas the results in the case of propane or butane can involve the higher initial activity and a lower deactivation of the tungsten catalyst, in the case of ethane, mechanistic or kinetic aspects can be envisaged in particular concerning the difficulty to dehydrogenate ethane into ethylene.     

Direct ethoxylation of a longer-chain aliphatic ester

2-Ethylhexyl laurate, as an exemplary longer-chain aliphatic ester, was subjected to direct ethoxylation. The synthesis was described and the obtained products were analyzed qualitatively by means of the mass spectrometry and chromatographic methods. Solubility of the obtained ethoxylates was studied by determination of their cloud points in selected model solutions. It was shown that longer-chain aliphatic esters are feasible as raw materials for ethoxylation in the presence of an appropriate catalyst. They undergo effective and selective reaction with ethylene oxide without formation of excessive amounts of by-products. The obtained products exhibit typical properties of ethoxylate-type nonionic surfactants. Their solubility in water and butyldiglycol solution was relatively lower compared to their methyl ester equivalents.     

Comparison of metathesis activity of catalysts prepared by anchoring of MoO2(acac)2 on various supports

The properties and olefin metathesis activity of molybdena–alumina, molybdena–silica–alumina and molybdena–silica catalysts prepared by anchoring of MoO₂(acac)₂ complex were compared. The specific activity obtained for molybdena–silica–alumina system is higher than that of molybdena–alumina and molybdena–silica catalysts. This statement concerns also the catalysts treated with tetramethyltin