聚丙烯腈树脂负载催化剂在聚酮合成中的应用

采用丙烯腈与二乙烯基苯交联合成聚丙烯腈树脂微球,考察了聚合工艺条件对微球的粒径、硬度等的影响.以负载有乙酸钯的聚丙烯腈树脂微球组成的催化体系催化一氧化碳和苯乙烯共聚合成聚酮(STCO).研究了催化体系中的2,2'-联吡啶和对苯醌用量及反应时间对共聚反应的影响.利用红外光谱(IR)和扫描电镜(SEM)对树脂负载催化剂及聚合产物进行了表征.结果表明,树脂负载催化剂对聚酮合成反应具有较好的催化性能:当树脂用量为1g,乙酸钯为22.4mg时,聚酮产量达6.2384g.另外树脂在重复使用5次后仍具有一定的催化活性.     

聚苯乙烯负载钯催化剂合成及催化共聚性能研究

合成了聚苯乙烯负载邻菲咯啉/钯配合物催化剂(PS-phen/Pd(OAc)2和PS-phen/PdCl2)。采用红外光谱(FT-IR)、X光电子能谱(XPS)、元素分析(EA)、原子吸收(AAS)及热重分析(TGA)等手段对该负载钯催化剂的结构和性质进行了系统表征。评价了聚苯乙烯负载钯催化剂在苯乙烯与CO共聚反应合成聚酮(PK)中的催化性能,结果表明,在温度为65℃,CO压力为3.0 MPa的条件下,PS-phen/Pd(OAc)2和PS-phen/PdCl2的催化活性分别为1.02×104gPK/mol Pd.h和5.50×103gPK/mol Pd.h,循环使用三次后,催化活性分别降至570 gPK/mol Pd.h和97.4 gPK/molPd.h。负载催化剂PS-phen/Pd-Cl2和PS-phen/Pd(OAc)2催化得到的苯乙烯/CO共聚产物的重均分子量(-Mw)较大,分别为6.86×103g/mol和7.33×103g/mol。     

IVB族西佛碱烯烃聚合催化剂及其制备方法

本发明是IVB族西佛碱烯烃聚合催化剂及其制备方法。该类催化剂由于高活性特点，目前是人们研究的重点。本发明将脂肪族胺与3-烃基水杨醛制得西佛碱配体后，再与正丁基锂或KH成盐，将MCl4滴入盐溶液反应得西佛碱烯烃聚合催化剂。将上述催化剂与烯烃单体共聚反应，得高分子化的西佛碱烯烃聚合催化剂，该类催化剂制备条件温和，催化效果良好。     

钴锌双金属氰化物/戊二酸锌复合催化剂催化CO2与环氧丙烷的共聚反应

制备了钴锌双金属氰化物/戊二酸锌(DMC-P123/ZnGA)复合催化剂并用于催化CO2与环氧丙烷(PO)共聚反应。采用热重分析、X射线衍射和扫描电镜对催化剂进行了表征。结果表明,DMC-P123以更小粒径均匀分散到ZnGA中;该催化剂对于CO2与PO共聚反应有较高的催化效率,并得到高相对分子质量的聚碳酸亚丙酯(PPC);当反应温度为60℃,反应时间为12 h时,催化效率大于550 g聚合物/g催化剂,PO的转化率达到94%;所得共聚产物的数均相对分子质量达到6万,碳酸酯链节含量大于68%,CO2固定率达到30%。     

新型聚合物——聚酮

讨论了聚酮的化学改性，物理改性，聚酮光降解机理以及贵金属催化－氧化碳和烯烃交替共聚制备聚酮的机理。     

极性单体与烯烃共聚反应的研究进展

综述了Ziegler—Natta催化荆、茂金属催化荆及后过渡金属催化剂在极性单体与烯烃共聚合反应中的研究进展。展望了极性单体与烯烃共聚反应研究的发展方向。     

铈锆氧化物固溶体的制备、表征及三效催化性能

采用共沉淀技术制备了Ce0.6Zr0.4O2固溶体,并对其进行了XRD、Raman光谱和SEM表征.将其用于单钯三效催化剂的制备,考察了Ce06Zr0.4O2对三效催化剂性能的影响.结果表明:Ce0.6Zr0.4O2具有和CeO2相似的立方结构,并具有较高的热稳定性;与含CeO2的三效催化剂相比,含Ce06Zr0.4O2的三效催化剂经高温老化后,仍具有较高的HC、CO、NO转化率和较低的起燃温度.     

有机废气催化燃烧用贵金属钯整体式催化剂的研究

催化燃烧法是当前处理挥发性有机废气最有前景的方法.贵金属钯催化剂对有机废气具有较高的催化燃烧活性,因此研究钯整体式催化剂用于有机废气的洁净化处理具有较好的工业应用前景.主要介绍了化学镀法制备贵金属钯整体式催化剂的基本原理、特点和制备工艺.     

PVP负载钯纳米丝状催化剂的制备及催化加氢性能

用电纺丝技术和加热交联技术制备了聚乙烯吡咯烷酮(PVP)负载纳米钯的纳米丝状催化剂PVP-Pd,并对所制备的催化剂进行了SEM,TEM,UV和TG的表征。利用PVP-Pd对烯烃和硝基苯的催化氢化反应研究了所制备催化剂的催化性能,结果表明纳米纤维态PVP-Pd催化剂在室温、氢气条件下催化氢化α-辛烯和环己烯的转化率可以达到100%,对硝基苯也有很好的催化活性。     

CO/乙烯/丙烯酸丁酯三元共聚及产物的结构表征

钯（Ⅱ）－ＤＤＤＰ（,双二苯基膦丙烷）催化剂可催化ＣＯ／乙烯／丙烯酸丁酯三元共聚）。考察了催化剂浓度、反应时间、溶剂以及丙烯酸丁酯单体用量对共聚反应的影响。     

钯催化冰片烯与一氧化碳的共聚反应

以α-蒎烯为原料合成冰片烯,以冰片烯作为聚合单体在氯化钯催化下与CO进行共聚反应。考察了氯化钯用量、反应温度、反应时间和反应压力对聚合反应的影响,结果表明,当n(Pd2+)/n(冰片烯)为0.01,CO压力2.5 MPa,搅拌速度120 r/min,反应温度60℃条件下反应2 h,冰片烯/CO共聚产物得率最高为22.03%,催化活性为4.4×102g PK/(mol.Pd.h);采用红外光谱(FT-IR)、凝胶渗透色谱(GPC)和元素分析(EA)等方法对冰片烯/CO聚合产物的结构进行了表征,结果表明,所得到的冰片烯/CO共聚物为严格线性交替共聚物,-Mw=1.5×103g/mol,-Mn=1.1×103g/mol,D=-Mw/M-n=1.36。     

脂肪族聚碳酸酯研究现状EI

介绍了从二氧化碳和环氧化物共聚制备脂肪族聚碳酸酯的研究现状,包括反应的催化体系、反应机理、反应条件、产物性质、改性方法和应用等。     

Catalytic oxidation of cyclohexane by size-selected palladium clusters pinned on graphite

We report the catalytic oxidation of cyclohexane to CO and CO₂ over size-selected palladium clusters (Pd _N clusters, N = 10–120) supported on graphite as a function of cluster size. The stability of the pinned clusters (nanoparticles) under reaction conditions is investigated by scanning tunnelling microscopy measurement both before and after reaction. Temperature-programmed reaction experiments at 800 Torr show that the turnover rates (per surface Pd atom) for both CO and CO₂ increase significantly as cluster size decreases and correlate with the number of Pd perimeter atoms at the graphite interface. Under oxygen-rich conditions, the activity of the clusters increases by a factor of 3 while the product ratio CO:CO₂ rises by an order of magnitude.     

MCM-41负载戊二酸锌催化剂催化CO2和环氧丙烷的共聚反应

制备了MCM-41负载戊二酸锌催化剂(ZnGA/MCM-41),并采用热重分析、红外光谱和X射线衍射对催化剂进行了表征。结果表明,ZnGA与载体间存在相互作用,ZnGA能以更小的粒径均匀分散到MCM-41的表面。实验研究表明,该催化剂对于CO2与环氧丙烷(PO)共聚反应显示出较高的催化效率,并得到高分子量的聚碳酸亚丙酯(PPC);通过调节负载量和催化剂的用量,最高催化效率达到了89.5g聚合物/g ZnGA;共聚产物的红外光谱和核磁数据表明,所得共聚产物具有接近完全交替(>97.4%)的碳酸酯结构。     

钯纳米线的制备及其在乙醇燃料电池中的应用

以阳极氧化铝为模板制备了具有高度有序微观结构的金属钯的纳米线,SEM分析表明,钯纳米线直径为50nm,且直立于电极表面,循环伏安扫描表明,在碱性环境中,钯纳米线对乙醇电氧化具有很高的催化活性,起峰点位在-0.58V,峰电流密度达到89.6mA/cm^2,正扫时的峰很尖锐,说明随着电压的升高,电极表面的乙醇被迅速消耗,因而钯纳米线对乙醇催化有很高的活性。     

CO oxidation catalyzed by single-walled helical gold nanotube

We study the catalytic capability of unsupported single-walled helical gold nanotubes Au(5,3) by using density functional theory. We use the CO oxidation as a benchmark probe to gain insights into high catalytic activity of the gold nanotubes. The CO oxidation, catalyzed by the Au(5,3) nanotube, proceeds via a two-step mechanism, CO + O2 --> CO2 +O and CO + O --> CO2. The CO oxidation is initiated by the CO + O2 --> OOCO --> CO2 + O reaction with an activation barrier of 0.29 eV. On the reaction path, a peroxo-type O-O-CO intermediate forms. Thereafter, the CO + O --> CO2 reaction proceeds along the reaction pathway with a very low barrier (0.03 eV). Note that the second reaction cannot be the starting point for the CO oxidation due to the energetically disfavored adsorption of free O2 on the gold nanotube. The high catalytic activity of the Au(5,3) nanotube can be attributed to the electronic resonance between electronic states of adsorbed intermediate species and Au atoms at the reaction site, particularly among the d states of Au atom and the antibonding 2pi* states of C-O and O1-O2, concomitant with a partial charge transfer. The presence of undercoordinated Au sites and the strain inherent in the helical gold nanotube also play important roles. Our study suggests that the CO oxidation catalyzed by the helical gold nanotubes is likely to occur at the room temperature.     

Synthesis of surface controlled nickel/palladium hydride nanodendrites with high performance in benzyl alcohol oxidation

Benzaldehyde byproduct is an imperative intermediate in the production of fine chemicals and additives. Tuning selectivity to benzaldehyde is therefore critical in alcohol oxidation reactions at the industrial level. Herein, we report a simple but innovative method for the synthesis of palladium hydride and nickel palladium hydride nanodendrites with controllable morphology, high stability, and excellent catalytic activity. The synthesized dendrites can maintain the palladium hydride phase even after their use in the chosen catalytic reaction. Remarkably, the high surface area morphology and unique interaction between nickel-rich surface and palladium hydride (β-phase) of these nanodendrites are translated in an enhanced catalytic activity for benzyl alcohol oxidation reaction. Our Ni/PdH_0.43 nanodendrites demonstrated a high selectivity towards benzaldehyde of about 92.0% with a conversion rate of 95.4%, showing higher catalytic selectivity than their PdH_0.43 counterparts and commercial Pd/C. The present study opens the door for further exploration of metal/metal-hydride nanostructures as next-generation catalytic materials.

     

Aqueous phase reforming of glycerol over the Pd loaded Ni/Al2O3 catalysts

Bifunctional catalysts containing (0.5-1.5 wt%) palladium and 15 wt% of Nickel supported on gamma-Al2O3 were prepared via an impregnation technique and catalysts were characterzed by XRD BET surface area and SEM, respectively. The aqueous phase reforming of glycerol (APR) was conducted over alumina-supported catalysts at different reaction conditions for catalytic activity. Finally, we concluded that the 1.0 wt% Pd 15 wt% Ni/gamma-Al2O3 catalyst evidences higher conversion, hydrogen selectivity, lower alkane selectivity and CO production. This indicate that Pd loaded Ni/gamma-Al2O3 could be a potential catalyst for the APR of glycerol.     

Palladium nanoparticle-graphene hybrids as active catalysts for the Suzuki reaction

Graphene has been successfully modified with palladium nanoparticles in a facile manner by reducing palladium acetate [Pd(OAc)₂] in the present of sodium dodecyl sulfate (SDS), which is used as both surfactant and the reducing agent. The palladium nanoparticle-graphene hybrids (Pd-graphene hybrids) are characterized by high-resolution transmission electron microscopy, atomic force microscopy, Raman spectroscopy, X-ray photoelectron spectroscopy, X-ray diffraction, and energy dispersive X-ray spectroscopy. We demonstrate that the Pd-graphene hybrids can act as an efficient catalyst for the Suzuki reaction under aqueous and aerobic conditions, with the reaction reaching completion in as little as 5 min. The influence of the preparation conditions on the catalytic activities of the hybrids is also investigated.