磷对Ni(Co)Mo(W)/Al2O3加氢处理催化剂的影响研究进展

Ni(Co)Mo(W)/Al2O3催化剂是工业中最常用的加氢处理催化剂.磷作为Ni(Co)Mo(W)/Al2O3加氢处理催化剂中较为常用的添加剂,用于改善催化剂的物理化学性质.本文从磷对Ni(Co)Mo(W)/Al2O3加氢催化剂孔结构、酸性、活性组分分散度等理化性能以及磷对加氢脱硫(HDS)和加氢脱氮(HDN)催化性能两个方面的影响对文献研究结果进行了综述,对磷添加剂的研究结果、存在的分歧以及研究机会进行了分析讨论.     

Oxidation of poly(1-trimethylsilyl-1-propyne)

The oxidation of poly(1-trimethylsilyl-1-propyne) (PMSP) proceeded normally in air at room temperature and under mild thermal conditions. Two different bands assigned to the carbonyl groups on a side chain and on a decomposed chain end were found in the IR spectra of the oxidized PMSP membrane. However, no band assigned to a hydroxyl group was observed. An allyl-type methyl group of the PMSP was mainly autooxidized without a decrease in molecular weight at room temperature. Only the former band assigned to the carbonyl groups appeared and it had a shoulder peak. In the case of mild thermal oxidation, the decomposition started in the backbone chain and both bands appeared. When the thermal oxidation proceeded further, all bonds were broken and various carbonyl and siloxane bonds were then randomly produced. © 1994 John Wiley & Sons, Inc.     

Polymerization of olefins with bulky substituents. 1. Homo- and copolymerization of 3-(1-adamantyl)propene

The use of bulky substituents like adamantane has been shown in the past to influence the glass transition temperatures of polymers significantly. In this paper the synthesis and homopolymerization of the monomer 3-(1-adamantyl) propene is described, as well as the copolymerization of this monomer with ethene, propene, 1-pentene, 4-methyl-1-pentene, 1-hexene and 1-octene. The resultant copolymers proved to be largely insoluble in organic solvents. It was also demonstrated that the presence of the bulky methyladamantyl side group influenced the glass transition temperatures of the copolymers in comparison with the corresponding homopolymers.     

Polymerization of substituted acetylenes by (mesitylene)M(CO)3 (M=W,Mo)

Summary Phenylacetylene could be polymerized by (mesitylene)W(CO)₃ in CCl₄ to give a polymer with 12,000 in ca. 80% yield. UV irradiation was unnecessary unlike the W(CO)₆–CCl₄-h catalyst. The present polymerization did not proceed in toluene. The (mesitylene)W(CO)₃ catalyst afforded high molecular weight polymers from phenylacetylenes bearing bulky substituents (e.g., Me₃Si and CF₃) at the ortho position. The Mo counterpart, (mesitylene)Mo(CO)₃, catalyzed the polymerization of 1-chloro-2-phenylacetylene and 1-chloro-1-octyne to provide high molecular weight polymers . Catalytic amounts of Lewis acids accelerated the polymerization of phenylacetylene by (mesitylene)W(CO)₃, but decreased the polymer molecular weight; this polymerization proceeded not only in CCl₄ but also in toluene.     

Glow-discharge-induced graft polymerization of acrylic acid onto poly[1-(trimethylsilyl)-1-propyne] film

Graft polymerization of acrylic acid onto poly[1-(trimethylsilyl)-1-propyne] [poly(TMSP)] film was examined. The water contact angle of poly(TMSP) film decreased remarkably from 90 to 15° by plasma treatment, which gradually increased up to 40° after several days. When the film exposed to a glow discharge was heated in an aqueous solution of acrylic acid at 80°C for 24 h, graft polymerization proceeded on the film surface, which was confirmed by ATR-IR and ESCA spectra. Graft polymerization effectively occurred above a threshold temperature (80°C). The water contact angle of the grafted film was about 30°, and did not change with time. In contrast, when a poly(TMSP) film exposed to UV irradiation was heated in an aqueous solution of acrylic acid, graft polymerization took place not only on the film surface but also inside the film.     

Crosslinking poly(1-trimethylsilyl-1-propyne) and its effect on solvent resistance and transport properties

Poly(1-trimethylsilyl-1-propyne) (PTMSP) has been crosslinked using 3,3′-diazidodiphenylsulfone to improve its solvent resistance. This study reports the influence of crosslinker content on the solubility properties of PTMSP, its density, and its gas sorption and transport properties. Crosslinking PTMSP renders it insoluble even in excellent solvents for the uncrosslinked polymer. Gas permeability and fractional free volume (FFV) decreased as crosslinker content increased, while gas sorption was unaffected by crosslinking. Therefore, the reduction in permeability upon crosslinking PTMSP was due to decreases in diffusion coefficients. Permeability reductions due to crosslinking could be offset by adding nanoparticles to the films. The addition of 30 wt.% fumed silica nanoparticles increased the permeability of crosslinked PTMSP by approximately 80%. In mixed gas permeation experiments, when the composition of the feed gas was 98 mol% CH₄ and 2 mol% n-C₄H₁₀, uncrosslinked PTMSP had an n-C₄H₁₀/CH₄ selectivity of 31 and an n-C₄H₁₀ permeability of 114,000 barrers at 35 °C and 14 atm feed fugacity. At the same conditions, crosslinked PTMSP containing 5 wt.% crosslinker had an n-C₄H₁₀/CH₄ selectivity of 28 and an n-C₄H₁₀ permeability of 73,000 barrers, and crosslinked PTMSP containing 5 wt.% crosslinker and 30 wt.% fumed silica nanoparticles had an n-C₄H₁₀/CH₄ selectivity of 21 and an n-C₄H₁₀ permeability of 110,000 barrers.     

Composite membrane of poly(1-(trimethylsilyl)-propyne) as a potential oxygen separation membrane

A special affinity of poly(1-(trimethylsilyl)-1-propyne), PMSP, toward other materials has been investigated. The oxygen permeability of PMSP thin membranes decreased with time, depending on the environmental conditions in which the membrane was kept. It was observed that PMSP has high gas solubility coefficients compared with other polymers from sorption measurements. From the results the deterioration of the membrane was explained essentially in terms of absorbance of some additives to PMSP membrane having a certain morphology. In composite membranes produced from such mixtures a generation of an interface layer between PMSP and an additive was demonstrated using a bilayered model membrane consisting of PMSP and porous polysulphone membrane. A three-layered composite membrane (silicone-copolymer/PMSP/polysulphone) designed on the basis of the results was shown to have high oxygen permeability, high separation factor and high durability.     

Rationalizing the catalytic performance of γ-alumina-supported Co(Ni)–Mo(W) HDS catalysts prepared by urea-matrix combustion synthesis

A comparative study of the influence of Co (or Ni) promoter loadings and the effect of different sulfurizing agents and sulfurizing temperatures on the structure, morphology and catalytic performance of Mo- or W-based hydrodesulfurization (HDS) catalysts was carried out. Catalyst performance using a tubular fixed-bed reactor and the HDS of thiophene as a model reaction was evaluated. The oxidic and sulfurized states of the HDS catalysts were characterized by laser Raman spectroscopy, thermogravimetric analysis (TGA), differential scanning calorimetry (DSC) and high resolution transmission electron microscopy (HRTEM). It has been found that the urea-matrix combustion (UMxC) synthesis is a simple tool for preparing supported catalysts in a short period of thermal treatment. Several consecutive stages such as urea melting, metal precursor dissolution and chemical reactions take place before and upon combustion process. The C₄H₄S/H₂-activated Co- (or Ni-) promoted MoS₂ (or WS₂) catalysts present a strong synergistic effect (SE) when the Co (or Ni)/Mo (or W) molar ratio is near to 0.5, whereas the C₄/C ₄ ⁼ molar ratios display a weak antagonistic effect. Alumina-supported Ni–W catalyst showed an optimal SE 2.5 times higher than those for Co (or Ni)-promoted Mo HDS catalysts. The kinetic parameters for thiophene-HDS reaction were also determined, suggesting that the C–S bond cleavage reaction for alumina-supported Co(Ni)–Mo HDS catalysts and H₂ activation reaction for Ni-promoted WS₂catalysts play an important role in the rate-limiting step.     

Bromination and gas permeability of poly(1-trimethylsilyl-1-propyne) membrane

The bromination of poly(1-trimethylsilyl-1-propyne) (PMSP) was carried out by immersing a PMSP membrane in bromine water at 25°C. The bromine mainly reacted at the carbon–carbon double bonds in the backbone chain, and carbon–carbon single bonds were produced, which was determined from the infrared (IR) and ultravilet (UV)–visible analyses. The glass transition temperature of the PMSP is above 350°C, but a new endothermic peak appeared between 50 and 80°C in the differential scanning calorimetry (DSC) curves of all brominated PMSPs. The permeability for 12 gases in the PMSP membrane and its brominated membranes was investigated between 30 and 90°C below 1 atm. With increasing bromine content in the membrane, the permeability coefficient for all gases decreased together with the diffusion coefficient, and the ideal separation factor for the industrially important gas pairs increased at 30°C. A distinct change in slopes at near the endothermic temperature determined by the DSC analysis was observed in Arrhenius plots of the permeability coefficients in all brominated PMSP membranes. © 1994 John Wiley & Sons, Inc.     

Negative thermal expansion of (Al1/3Fe1/3Cr1/3)2(Mo1/2W1/2)3O12 (AFCMW) and low thermal expansion of AFCMW-(Co1/2Ni1/2)(Mo1/2W1/2)O4 with high entropy

A₂Mo₃O₁₂ (A-Al, Fe, Cr) have large negative thermal expansion (NTE) coefficients and structural stability but high phase-transition temperatures (PTTs). Herein, we prepared (Al_1/3Fe_1/3Cr_1/3)₂(Mo_1/2W_1/2)₃O₁₂ (AFCMW), and found it to have a low NTE coefficient and a low PTT. Furthermore, combination of AFCMW with (Co_1/2Ni_1/2)(Mo_1/2W_1/2)O₄ (CNMW) afforded an AFCMW–CNMW composite with a low thermal expansion (LTE). We determined that the PTT reductions in A₂Mo₃O₁₂ are largely due to the high-entropy effect resulting from the introduction of different ions into its A and M sites. Moreover, we found that the low LTE of the AFCMW–CNMW composite is attributable to the opposite thermal expansion behaviours of AFCMW and CNMW. We suggest that the suppressed thermal expansion during the phase transition process of the AFCMW–CNMW composite could be derived from the high-entropy effect resulting from its increased diversity of polyhedra, the influence of Co²⁺ and Ni²⁺ dopants, and CNMW-induced lattice distortion.     

Study on the geometric structure of poly[1-(trimethylsilyl)-1-propyne] by 13C and 29Si NMR spectroscopies

Summary The geometric structure of poly[1-(trimethylsilyl)-1-propyne] was investigated by ¹³C and ²⁹Si NMR spectroscopies. According to ¹³C NMR, the geometric structure varied with polymerization catalysts. NbCl₅ was inferred to produce more cis-rich polymer than TaCl₅. On the other hand, polymerization conditions such as solvent, temperature and cocatalyst hardly affected the geometric structure. The cis contents of polymers bearing bulkier substituents (-SiMe₂-nC₆H₁₃,-SiMe₂-CH₂SiMe₃) prepared with TaCl₅ were similar to that of poly (TMSP) with TaCl₅.     

Enhanced gas transport properties and molecular mobilities in nano-constrained poly[1-(trimethylsilyl)-1-propyne] membranes

Interfacial constraints in ultrathin poly(l-trimethylsilyl-1-propyne) (PTMSP) membranes yielded gas permeabilities and CO₂/helium selectivities that exceed bulk PTMSP membrane transport properties by up to three-fold for membranes of submicrometer thickness. Maximum permeability coefficients of 110 × 10³ Barrer and 27 × 10³ Barrer for carbon dioxide and helium, respectively, were found to occur in membranes of ～750 nm thickness. Indicative of a free volume increase, a molecular energetic mobility analysis (involving intrinsic friction analysis) revealed enhanced methyl side group mobility. This was evidenced by a minimum in the activation energies of ～4 kcal/mol in thin PTMSP membranes with maximum permeation, compared to ～5.5 kcal/mol in bulk films. Aging studies conducted over the timescales relevant to the conducted experiments signify that the free volume states in the thin film membranes are highly unstable in the presence of sorbing gases such as CO₂. These results are discussed and contrasted to PTMSP bulk membrane systems, which were found to be unaffected by aging over the equivalent experimental time scale.     

The polymerization of propargyl halides (Cl,Br) using M(CO)5PPh3/R x AlCl3-x (M=Mo,W) as catalysts

Summary Propargylchloride (PCl) and propargylbromide (PBr) were polymerized in good yields using M(CO)₅PPh₃/R_xAlCl_3-x as catalysts (M=W, Mo). Mo was found to be more effective than W. The presence of chlorine atoms in co-catalyst was important for the activation of the catalyst. The obtained polymers were coloured, insoluble in all organic solvents and stable until 150°C. From their IR and ESR spectra is concluded that the polymers have highly conjugated structures. The oligomeric products were constituted mainly from cyclotrimers. In the case of Mo-catalyst only 1,2,4-cyclotrimer was obtained; a mixure of 1,2,4 and 1,3,5-derivatives were formed using W-catalysts.     

Hexavalent (Me - W/Mo)-modified (Ba,Ca)TiO3-Bi(Mg,Me)O3 perovskites for high-temperature dielectrics

We report on the synthesis of complex lead-free perovskite-type (1−x)(Ba_0.8Ca_0.2)TiO₃–xBi(Mg_0.75W_0.25)O₃ (BCT-xBMW) and (1−x)(Ba_0.8Ca_0.2)TiO₃-xBi(Mg_0.75Mo_0.25)O₃ (BCT-xBMM) solid solutions via conventional solid-state reaction route. The sintering temperature was adjusted as a function of composition x to obtain dense samples (relative densities over 95%) at the same time minimizing bismuth evaporation. X-ray diffraction analysis shows the formation of single-phase perovskites for 0 ≤ x ≤ 0.10 in the BCT-xBMW series and increasing concentrations of impurity phases for x ≥ 0.15 and for x ≥ 0.05 in BCT-xBMM. A transition from a tetragonal to pseudo-cubic perovskite structure is observed in BCT-xBMW and BCT-xBMM at x = 0.05. The dielectric response has been characterized between −60°C and 300°C for BCT-xBMW, and between 30°C and 300°C for BCT-xBMM using impedance spectroscopy, showing a transition from ferroelectric to relaxor-like behavior at x ≥ 0.05. Additional polarization and Raman spectroscopy measurements reveal the occurrence of highly disordered systems. Analysis of the Raman spectra indicates structural phase changes and lattice modifications caused by chemical substitution. For the composition 0.8Ba_0.8Ca_0.2TiO₃-0.2Bi(Mg_0.75W_0.25)O₃, a temperature-stable permittivity of about 600 (±15% between −60°C and 300°C) and small losses of tanδ < 0.02 for T ≤ 230°C at 1 kHz are observed_, making it a suitable dielectric material for high-temperature capacitors.     

Synthesis of poly[1-(trimethylsilyl)-1-propyne] with a narrow molecular weight distribution by using NbCl5 catalyst in cyclohexane

Summary A new monomer 4 has been prepared from the reaction of p-phenylenediamine and excess of thionyl chloride. Reaction of 4 with benzidine in NMP or DMF at elevated temperature resulted a new polymer having -NH-SO-NH-functionality in the backbone. The monomer and the polymer have been characterized by elemental analyses and spectroscopic informations.     

Molecular characteristics of poly(1-trimethylsilyl-1-propyne) in dilute solutions

Samples and fractions of a membrane-forming polymer, poly(1-trimethylsilyl-1-propyne) (PTMSP), were studied by methods of molecular hydrodynamics (velocity sedimentation, translational isothermal diffusion and viscometry) in cyclohexane in the molecular mass range 60<M×10⁻³ g mol⁻¹<430. The following molecular-mass dependencies of the hydrodynamic characteristics (intrinsic viscosity [η] (cm³ g⁻¹), sedimentation coefficient s₀(s) and translational diffusion coefficient D₀ (cm² s⁻¹)) were established: [η]=0.198 M^0.50±0.06; s₀=8.66×10⁻¹⁶M^0.50±0.04; D₀=9.30×10⁻⁵M^{−0.50±0.04}. On the basis of the hydrodynamics data the equilibrium rigidity and hydrodynamic diameter of PTMSP chains were evaluated. The equilibrium properties of the different disubstituted polyacetylenes molecules are compared on the base of the normalised scaling plots.     

X射线荧光光谱法测定加氢精制催化剂中的镍、钼、钨和磷

通过模拟加氢精制催化剂组成制备一系列不同组分含量的标准样品,采用经验系数法校正基体效应,建立X射线荧光光谱法测定加氢精制催化剂中活性组分镍、钼、钨、磷含量的分析方法,测定范围（质量分数）：NiO,1.92%~7.1%;MoO₃,8.80%~13.69%;WO₃,8.81%~14.50%;P₂O₅,2.04%~6.96%。建立的4条定量校准曲线的相关系数均高于0.999,测定结果相对标准偏差均小于1%,具有较高的准确度和精密度,能很好地满足科研和工业生产的需求。     

Gas transport properties of MgO filled poly(1-trimethylsilyl-1-propyne) nanocomposites

Magnesium oxide (MgO) nanoparticles were dispersed via solution processing in poly(1-trimethylsilyl-1-propyne) (PTMSP) to form polymer nanocomposites. Transmission electron microscopy was used to determine the extent of particle aggregation in the composites. Both nanocomposite density and CO₂, CH₄, N₂, and H₂ permeability were influenced by nanoparticle loading. Nanocomposite densities were markedly lower than predicted by a two phase additive model. For example, in films containing 75 nominal volume percent MgO, the polymer-particle composite density was 68 percent lower than expected based on an additive model. At this loading, gas permeability coefficients were, depending on the gas, 17-50 times higher than in unfilled PTMSP at similar conditions. The changes in permeability with particle content were interpreted in terms of measured changes in gas solubility with particle content and diffusion coefficients calculated from the permeability and solubility data.     

Hydroisomerization of model FCC naphtha over sulfided Co(Ni)–Mo(W)/MCM-41 catalysts

Deep hydrodesulfurization (HDS) of gasoline generally brings about the saturation of olefins and leads to the serious octane number losses. Conversion of linear olefins to branched ones followed by hydrogenation to isoalkanes would minimize such octane number losses. In this work, MCM-41-supported Co–Mo, Ni–Mo and Ni–W catalysts were prepared by the incipient wetness impregnation method, and compared with an industrial Co–Mo/γ-Al₂O₃ catalyst. The surface acidities were measured by the techniques of microcalorimetry and infrared spectroscopy for the adsorption of ammonia, and probed by the reaction of conversion of isopropanol. The isomerization and hydrogenation of 1-hexene as well as the HDS of thiophene were studied by using model FCC naphtha. It was found that the sulfidation enhanced significantly the surface Brønsted acidity that favored the skeletal isomerization of 1-hexene under the HDS conditions. Since the isomerization and hydrogenation of 1-hexene are the two competition reactions, the catalysts with relatively lower hydrogenation activity may have higher selectivity to the isomerization reactions. The Co–Mo/MCM-41 showed the high selectivity to the skeletal isomerization reactions due to its strong surface Brønsted acidity and the relatively low hydrogenation activity. On the other hand, the Ni–Mo/MCM-41 exhibited high hydrogenation activity and therefore low selectivity to the isomerization reactions although it possessed quite strong surface Brønsted acidity. The Ni–W/MCM-41 exhibited the low activity for the HDS of thiophene and isomerization of 1-hexene due to the poor dispersion of active metals.     

1-(5-(4-氯苯基)-1-(2,4-二氯苯基)-4-甲基-1H-吡唑-3-基)-3-(吡啶-3-基甲基)脲的合成

以5-(4-氯苯基)-1-(2,4-二氯苯基)-4-甲基-1H-吡唑-3-甲酸与二氯亚砜为起始原料,经酰氯化反应、酰胺反应、霍夫曼重排以及水解反应生成中间体5-(4-氯苯基)-1-(2,4-二氯苯基)-3-氨基-4-甲基-1H-吡唑,再经过与氯甲酸苯酯反应、胺酯交换反应得到标题化合物,其结构经1HNMR、MS谱确证,总收率26.9%。