改进型甲醇合成催化剂NC208的催化特性

采用ＴＰＤ、ＸＲＤ、ＢＥＴ和Ｈ２Ｓ中毒试验等方法，对比研究三组份（Ｃｕ－Ｚｎ－Ａｌ）甲醇合成催化剂Ｃ２０７和添加少量金属氧化物的改进型催化剂ＮＣ２０８．结果表明，工作态ＮＣ２０８催化剂表面Ｃｕ＋／Ｃｕ０的比值和价态稳定性大于Ｃ２０７．     

CuCrAl和CuCrZr低温液相合成甲醇催化剂的研究

 用络合共沉淀法制备了CuCrAl和CuCrZr复合氧化物液相合成甲醇催化剂，其比表面分别达到119和116m2／g．在5．0～5．5MPa和383K条件下，分别用间歇式和流动式反应釜考察了催化剂的活性和稳定性．结果表明：CuCrAl和CuCrZr的活性均明显高于CuCr；CuCrAl的活性略高于CuCrZr，但甲酸甲酯（MF）的选择性明显低于CuCrZr；两者在12h内未见活性明显下降．甲醇钠在反应过程中部分转化为甲酸钠和NaOH．CuCrAl和CuCrZr有较高的氢解活性可抑制甲醇钠与MF生成甲酸钠，从而有较低的甲酸钠浓度．但是，Al2O3和ZrO2的酸性有利于甲醇脱水，引起甲醇钠水解生成NaOH．溶剂对CuCr基催化剂的活性和选择性有明显影响．对反应机理进行了讨论．     

cotpp-pt/c作直接甲醇燃料电池阴极催化剂

四苯基钴卟啉;pt催化剂;直接甲醇燃料电池;氧还原     

甲苯甲醇侧链烷基化反应中沸石催化剂酸碱中心的作用Ⅰ．改性的X型、X／ZSM－5型和KX型沸石催化剂

甲苯甲醇侧链烷基化反应中沸石催化剂酸碱中心的作用Ⅰ．改性的Ｘ型、Ｘ／ＺＳＭ－５型和ＫＸ型沸石催化剂李永光，畅晋英，王建平（太原工业大学化工系，太原０３００２４）关链词沸石，侧链烷基化，甲苯，甲醇甲苯甲醇烷基化反应有两种方式：在苯环上烷基化生成二甲苯；...     

Computer modeling for analysis of complex reaction kinetics

A new method for computer prediction of the catalytic activity dependence on service life and technological conditions for bifunctional Pt catalysts has been proposed. The proposed method is based on physical and chemical laws of multicomponent hydrocarbon transformations on polymetallic catalysts and takes into account deactivation of acidic (Al) and metallic (Pt) sites. It allows to calculate the product composition and catalytic activity level for real industrial units as a function of their technological parameters and raw material characteristics.     

An NMR study of methanol diffusion in polymer electrolyte fuel cell membranes

Methanol diffusion in two polymer electrolyte membranes, Nafion 117 and BPSH 40 (a 40% disulfonated wholly aromatic polyarylene ether sulfone), was measured using a modified pulsed field gradient NMR method. This method allowed for the diffusion coefficient of methanol within the membrane to be determined while immersed in a methanol solution of known concentration. A second set of gradient pulses suppressed the signal from the solvent in solution, thus allowing the methanol within the membrane to be monitored unambiguously. Over a methanol concentration range of 0.5–8 M, methanol diffusion coefficients in Nafion 117 were found to increase from 2.9 × 10⁻⁶ to 4.0 × 10⁻⁶ cm² s⁻¹. For BPSH 40, the diffusion coefficient dropped significantly over the same concentration range, from 7.7 × 10⁻⁶ to 2.5 × 10⁻⁶cm² s⁻¹. The difference in diffusion behavior is largely related to the amount of solvent sorbed by the membranes. Increasing the methanol concentration results in an increase in solvent uptake for Nafion 117, while BPSH 40 actually excludes the solvent at higher concentrations. In contrast, diffusion of methanol measured via permeability measurements (assuming a partition coefficient of 1) was lower (1.3 × 10⁻⁶ and 6.4 × 10⁻⁷ cm² s⁻¹ for Nafion 117 and BPSH 40 respectively) and showed no concentration dependence. The differences observed between the two techniques are related to the length scale over which diffusion is monitored and the partition coefficient, or solubility, of methanol in the membranes as a function of concentration. For the permeability measurements, this length is equal to the thickness of the membrane (178 and 132 μm for Nafion 117 and BPSH 40 respectively) whereas the NMR method observes diffusion over a length of approximately 4–8 μm. Regardless of the measurement technique, BPSH 40 is a greater barrier to methanol permeability at high methanol concentrations.     

晶态氮化碳薄膜的低温合成

The synthesis of carbon nitride films at low temperature has been investigated using pulsed arc discharge from methanol solution with nitrogen atmosphere. Raman spectra and X-ray diffraction (XRD) analysis suggest that crystalline carbon nitride films may be prepared at low substrate temperature (220 ℃). At same time, the substrate temperature has a significantly effect on the nitrogen content and structure of the films. Increasing substrate temperature (300 ℃) would decrease the content of nitrogen in the films and result in a formation of carbon films.     

Two-step preparation for catalyst-free biodiesel fuel production

Biodiesel fuel was prepared by a two-step reaction: hydrolysis and methyl esterification. Hydrolysis was carried out at a subcritical state of water to obtain fatty acids from triglycerides of rapeseed oil, while the methyl esterification of the hydrolyzed products of triglycerides was treated near the supercritical methanol condition to achieve fatty acid methyl esters. Consequently, the two-step preparation was found to convert rapessed oil to fatty acid methyl esters in considerably shorter reaction time and milder reaction condition than the direct supercritical methanol treatment. The optimum reaction condition in this two-step preparation was 270°C and 20 min for hydrolysis and methyl esterification, respectively. Variables affecting the yields in hydrolysis and methyl esterification are discussed.     

Dielectric Relaxation Study of Liquids Having Chloro Group with Associated Liquids. I. Chlorobenzene with Methanol, Ethanol, and 1-Propanol

The complex permittivity for chlorobenzene–alcohol binary mixtures have been determined over the frequency range of 10 MHz to 20 GHz, at 15, 25, 35, and 45°C, using the time-domain reflectometry (TDR) method for 11 concentrations of each chlorobenzene–alcohol system. The alcohols used were methanol, ethanol, and 1-propanol. The values of static dielectric constant, relaxation time, the corresponding excess properties, the Redlich–Kister coefficients up to the third order, the Kirkwood correlation factor, and thermodynamic parameters of the mixtures have been determined. The excess permittivity is found to be negative for chlorobenzene–methanol and chlorobenzene–ethanol, whereas it is positive in the 1-propanol rich region. The excess inverse relaxation time is negative for all the systems studied here. The Kirkwood effective correlation factor increases with an increasing in the molecular size of the alcohol, but decreases with increasing temperature.     

Selective synthesis of isobutanol by means of the Guerbet reaction: Part 2. Reaction of methanol/ethanol and methanol/ethanol/n-propanol mixtures over copper based/MeONa catalytic systems

The synthesis of isobutanol via the Guerbet condensation between methanol and ethanol was studied by using sodium methoxide (MeONa) as soluble basic component and copper-based catalysts as heterogeneous dehydrogenating/hydrogenating metal species. The effect of the nature of the catalyst and the relative amount of its individual components with respect to the reacting alcohols as well as of temperature on productivity and selectivity of the process was investigated. The collected data indicated that the copper chromite/MeONa was more active than Cu-Raney/MeONa system. The reaction was shown to proceed with the formation only of n-propanol and isobutanol. Ethanol conversion up to 61% with selectivity to isobutanol up to 98.4% was obtained. The same catalytic systems were also employed in the reaction of the methanol/ethanol/n-propanol ternary mixture. Again copper chromite/MeONa resulted more active than the Cu-Raney/MeONa system. Finally, experiments were carried out on methanol/n-propanol mixtures in the presence of the copper chromite/MeONa catalytic system by recycling both the recovered solid copper component and the liquid reaction mixture for evidencing eventual copper leaching by MeONa. On the basis of the obtained results it was concluded that in the Guerbet reaction copper chromite works as heterogeneous catalyst.