Synthesis and characterization of poly(1-sila-cis-pent-3-enes) substituted with pendant pyridinyl groups

Poly[1-methyl-1-[3-(3-pyridinyl)propyl]-1-sila-cis-pent-3-ene], poly[1-phenyl-1-[3-(3-pyridinyl)propyl)-1-sila-cis-pent-3-ene], and poly[1-phenyl-1-(4-pyridinyl)-1-sila-cis-pent-3-ene] were synthesized by the anionic ring-opening polymerization of 1-methyl-1-[3-(3-pyridinyl)propyl]-1-silacyclopent-3-ene, 1-phenyl-1-[3-(3-pyridinyl)propyl]-1-silacyclopent-3-ene, and 1-phenyl-1-(4-pyridinyl)-1-silacyclopent-3-ene, respectively. These are the first polycarbosilanes which contain heterocyclic pyridine units as side-chain substituents. These polymers were characterized by¹H,¹³C, and²⁹Si NMR as well as by IR and UV spectroscopy. The molecular weight distributions were determined by gel permeation chromatography, glass transition temperatures, by differential seanning calorimetry: (DSC) and thermal behavior, by thermogravimetric analysis. (TGA).     

2,6，6-三甲基-3-肟基-1-环己烯-1-甲醛的合成

以柠檬醛为原料经苯胺保护、浓硫酸环化、亚硝化、水解制备得到2,6，6-三甲基-3-肟基-1-环己烯-1-甲醛，含量99．1％，收率50．1％。并对反应机理进行了分析。     

AlCl_3催化体系合成金刚烷

研究了AlCl3催化体系催化endo-TCD合成金刚烷。在常压搅拌反应器中考察了助催化剂、反应温度、反应时间、催化剂用量等因素对金刚烷收率的影响。实验表明,在温度为70℃,反应时间为6 h,AlCl3用量与endo-TCD的摩尔比为0.6,以2.5%Pt/C为助催化剂,其用量与催化剂的摩尔比为0.05的条件下,ADH的收率可达88.6%。     

3-[1-羟基-2,6,6-三甲基-4,4-(乙二氧基)-2-环己烯基]丙炔醇的合成及其稳定性研究

报道了标题化合物的合成,并针对与该化合物稳定性相关的因素进行了系统的分析研究,确定了其不稳定性主要表现在缩酮部位的水解;建立了用^1HNMR的方法跟踪监测该化合物的动态变化,该化合物及其分解后产物的结构都经过^1HNMR行了确证。     

Multifactorial analysis in the study of hydroformylation of oct-1-ene using supported aqueous phase catalysis

The influence of the hydration and the surface characteristics of five supports in the hydroformylation of oct-1-ene by supported aqueous phase catalysis (SAPC) using [Rh₂(μ-S^tBu)₂(CO)₂(TPPTS)₂] as catalyst was studied. The results confirm that the size of the pores and the amounts of water were found to be the determining factors contributing to the SAPC. According to the size of pores there is a critical value for which the SAPC takes place either in the classical model or in conditions where the pores are filled. When the pores are fully filled the SAPC can operate efficiently onto the external surface, stabilising the conversion in a relatively wide range of support hydration.     

V-W-Ti-Si/堇青石催化剂柴油机脱硝反应动力学

采用固定床反应器,以自制的V-W-Ti-Si/堇青石为催化剂,在消除内外扩散影响的基础上,考察了氨选择性催化还原反应(NH_3-SCR)过程,建立了幂指数型的脱硝反应动力学模型,并通过线性拟合确定了模型参数。结果表明,在自制的V-W-Ti-Si/堇青石催化剂上,NO,NH_3和O_2的反应级数分别为0.93,0,0.24,活化能为25.99 kJ/mol,模型拟合的相对误差在10%左右,可用于指导柴油机尾气脱硝催化剂反应过程研究与开发。     

Deactivation of a platinum reforming catalyst in a tubular reactor

This work concerns the methodology of characterizing the deactivation of a catalyst by coke deposition. The isomerization of n.pentane on a platinum reforming catalyst was studied in a tubular reactor permitting easy sampling of the gas phase at several positions in the reactor. Runs with high ratios of hydrogen to pentane did not show any deactivation and served to determine the kinetics of the main reaction and the principal side reaction, hydrocracking. At low ratios of hydrogen to pentane the catalyst was deactivated by carbonaceous deposits. At the end of the run the coke was determined in sections of the reactor and was found to be deposited according to a profile. Additional insight into the coking phenomenon was obtained from experiments on a thermobalance. A mathematical model for the performance of the tubular reactor subject to coking was set up and the parameters were determined from the experimental data. The parameters were found to be significantly determined and to obey the Arrhenius temperature dependence. The values of the parameters of the main reaction and of the hydrocracking side reaction which were derived from the experiments in the presence of coking were in agreement with those obtained from the runs in the absence of coking.     

反应条件下多孔催化剂上有效扩散系数及曲节因子的分析计算

采用CDS－810微反系统,在实验条件为：常压、氢苯比3.0-8.0、温度363.15K-453.15K时,进行了在四种不同粒度Ni/Al2O3催化剂上的气相苯加氢反应,利用实验数据计算了不同反应组成、不同反应速率时苯的有效扩散系数、反应死区及催化剂的曲节因子。计算结果表明：有效扩散系数不随反应速率改变,多孔催化剂的曲节因子可以看作多孔催化剂的结构参数,不随反应条件变化。     

碳三加氢催化剂的常见毒物

介绍了乙烯装置碳三馏分液相加氢反应及工艺,毒物是碳三液相加氢催化剂失活的重要原因之一。重点介绍了砷、硫、水、重金属对碳三催化剂运行的影响及毒物的脱除方法,控制好碳三反应器进料中的毒物,可以减缓催化剂活性下降,延长使用寿命。     

Methanol Partial Oxidation on MoO3/SiO2 Catalysts: Application of Vibrational Spectroscopic Imaging Techniques in a High Throughput Operando Reactor

A home-built, high-throughput operando (HTO) reactor was applied to study methanol partial oxidation reaction over MoO₃/SiO₂ catalysts. This HTO reactor combines Fourier transform infrared (FT-IR) imaging and Raman spectroscopy for high throughput catalyst evaluation and simultaneously for catalyst characterization under operando conditions. The catalyst activity and selectivity of all parallel reaction channels were followed at a time resolution of 2–20 s by the FT-IR imaging system that offers a spatial resolution of 16,384 pixels over a 2 × 2 inches illuminated cross-section area. Six specialized Raman probes were used to simultaneously collect Raman spectra of the catalyst surfaces and reaction intermediates under operando conditions. The structural variation of the MoO₃/SiO₂ catalysts with different molybdenum loadings and their catalytic performance at various temperatures were determined. The HTO reactor with the integrated imaging techniques allowed us to track the catalytic activities and the surface morphologies for multiple samples under various operando conditions.     

碘催化合成对-正丁基苯胺的正交实验研究

以碘作催化剂、以正丁醇与苯胺为原料在高压反应釜内催化合成对-正丁基苯胺,用GC-MS和气相色谱对产物进行定性和定量分析。通过正交实验确定最佳反应条件如下:反应温度300℃、反应时间10h、碘量0.910g(占苯胺质量的10‰)、搅拌速度450r·min-1,在此条件下,对-正丁基苯胺收率为49.84%,并在以负载型催化剂I2/Al2O3代替单质碘时达到55.51%。     

Performance of potassium 12-tungstophosphoric salts as catalysts for isobutane/butene alkylation in subcritical and supercritical phases

Potassium salts of H₃PW₁₂O₄₀ heteropolyacid have been synthesised with different K contents and studied for their acid and catalytic properties in liquid phase isobutane alkylation by but-2-ene or but-1-ene. Subcritical and supercritical conditions have been chosen for comparison in a batch reactor.

The influence of the protonic site density has been studied. High acid density was observed to be detrimental for akylation reaction which was explained by increased olefin dimerisation, the main side reaction responsible of catalyst poisoning. A K_2.6H_0.4P sample was tested in a batch reactor in liquid subcritical, near supercritical and in low and high density supercritical isobutane/butene mixture (418 K, P=4–9 MPa). An increase in the quality of the alkylate with the density of the supercritical phase was observed which almost counterbalanced the negative effect of the high temperature necessary to reach supercritical isobutane conditions.

In the presence of porous alkaline salts of 12-tungstophosphoric acid, alkylation to oligomerisation ratio is significantly improved over solids with a low density of strong Brønsted sites and by the use of high density supercritical isobutane conditions, the latter preserving hydride transfer and trimethyl pentane (TMP) formation.     

Monoterpene Composition of Pinus sylvestris Varieties Resistant and Susceptible to Dioryctria zimmermani

The proportion of monoterpenes and enantiomeric ratios of chiral monoterpenes were determined in two susceptible and two resistant varieties of Scotch pine, Pinus sylvestris, by capillary GC analysis of headspace volatiles emitted by 9-year-old trees. Half the trees sampled in each variety had been wounded by Dioryctria zimmermani, while the other half were unwounded. The presence of wounds had no significant (P < 0.05) effect on the proportion of monoterpenes or the ratio of enantiomers of each of the optically resolved monoterpenes in the four varieties. In contrast, monoterpene composition varied significantly (P < 0.05) among varieties. However, the results do not entirely support the putative role of car-3-ene and terpinolene as an oviposition stimulant for D. zimmermani in resistant varieties of Scotch pine. Although the resistant Lake Superior Blue virtually lacked these two monoterpenes, the resistant Belgian had a relatively high concentration of car-3-ene and terpinolene. Both resistant varieties, however, emitted relatively high levels of limonene, a monoterpene associated with increased oviposition in three other Dioryctria species. There was no evidence linking enantiomeric composition of chirally resolved monoterpenes with varietal resistance. The relative importance of monoterpenes as resistance factors and oviposition stimulants is discussed.     

Coupling non-isothermal trickle-bed reactor with catalyst pellet models to understand the reaction and diffusion in gas oil hydrodesulfurization

In this work, a trickle-bed reactor coupled with catalyst pellet model is employed to understand the effects of the temperature and catalyst pellet structures on the reaction–diffusion behaviors in gas oil hydrodesulfurization(HDS). The non-isothermal reactor model is determined to be reasonable due to non-negligible temperature variation caused by the reaction heat. The reaction rate along the reactor is mainly dominated by the temperature,and the sulfur concentration gradient in the catalyst pellet decreases gradually along the reactor, leading to the increased internal effectiveness factor. For the fixed catalyst bed volume, there exists a compromise between the catalyst reaction rate and effectiveness factor. Under commonly studied catalyst pellet size of 0.8–3 mm and porosity of 0.4–0.8, an optimization of the temperature and catalyst pellet structures is carried out, and the optimized outlet sulfur content decreases to 7.6 wppm better than the commercial level at 0.96 mm of the catalyst pellet size and 0.40 of the catalyst porosity.     

新型异丁烷脱氢催化剂性能

对异丁烷脱氢催化剂YBD-101和国外某催化剂L进行性能比较。采用XRD和BET研究催化剂的物相结构和比表面积,固定床反应器考察两种催化剂的异丁烷脱氢催化活性和产物选择性。结果表明,催化剂YBD-101较催化剂L具有Cr2O3颗粒细小和比表面积大等特点。在反应温度(500~620)℃和空速(1.0~2.0)h-1条件下,催化剂YBD-101的异丁烷转化率高于催化剂L8个百分点,产物选择性高于催化剂L 3个百分点。催化剂YBD-101的活性稳定性优于催化剂L,再生周期明显延长,具有较好的经济效益和社会效益。     

Ring-opening polymerization of 1 -ethylbicyclo[2.2.1] hept-2-ene

1-Ethylbicyclo[2.2.1]hept-2-ene has been polymerized using a range of metathesis catalysts and the structure of the polymers determined by ¹³C n.m.r. spectroscopy. For a given catalyst the cis double bond content was lower and the head-tail bias greater than for polymers of the 1-methyl analogue. This is interpreted in terms of enhanced steric and polar effects brought about by the ethyl substituent.     

催化剂载体对有机硅高沸物裂解反应的影响

以A型硅胶、C型硅胶、γ-氧化铝和MCM - 41分子筛为载体,采用浸渍法制成4种固载型氯化铝( AlCl3)催化剂；并以直接法合成甲基氯硅烷过程中副产的高沸物为原料,在自制的固定床反应器中进行裂解试验,评价了载体对裂解反应的影响.结果表明,这4种催化剂中,以C型硅胶固载AlCl3催化剂为佳.采用该催化剂催化高沸物的裂解反应的适宜工艺条件为:反应温度310℃,液时空速0.8 mL/(h·g-cat),此时二甲基二氯硅烷的收率为18.88％,且催化剂在48h内具有较好的稳定性.     

Thermal sintering studies of an autothermal reforming catalyst

This paper describes a novel approach to life studies on catalysts used in non-isothermal reactors, using a single long-term experiment. Temperature dependence of catalyst aging is determined by comparing the activity reduction of portions of the catalyst from different sections of the reactor, subjected to different temperatures. Time dependence is determined by fitting the drift in catalyst temperatures to a time-dependent reaction rate via a thermodynamic reactor model. Experimentally, a monolithic autothermal reforming catalyst was subjected to thermally accelerated aging under reforming conditions in an adiabatic laboratory mini-flow reactor for 1000 h. Methane was used as the fuel. The axial temperature profile of the catalyst was monitored using thermocouples placed at various locations along the catalyst. A gradual change in temperature profile, with increasing temperatures due to decreasing steam-reforming activity, was observed. The aged monolith was cut up into short pieces centered on the thermocouple locations. The pieces, each aged at a different temperature due to its location, were tested individually for activity. The reduced activities were correlated with the aging temperature to obtain the temperature dependence of thermal sintering rates. A generalized power-law equation (GPLE) model for sintering was fit to the activity data. A plug flow reactor (PFR) model describing the reaction was built and the sintering kinetics were incorporated. The PFR model was used to predict changes in catalyst performance due to sintering under normal operating conditions. Thermal sintering deactivation for this catalyst was found to be within acceptable limits for commercial applications.     

活性炭负载硅钨酸催化合成癸二酸二丁酯

以颗粒状活性炭负载硅钨酸作催化剂,由癸二酸和正丁醇反应合成癸二酸二丁酯,通过正交试验,探讨了主要因素对醋化率的影响。实验结果表明,活性炭负载硅钨酸具有良好的催化活性,当酸醇摩尔比为1:3.5,负载催化剂用量为癸二酸质量的10.9%,反应时间为1.5h.酯化率可达98.79%。     

Vapour phase oxidation of ethylene glycol to glyoxal on supported cupric oxide

The vapour phase oxidation of ethylene glycol to glyoxal by air was studied in a stainless steel tube reactor using cupric oxide as a catalyst on carriers such as active alumina, pumice stone, silicon carbide, ceramics and fused alumina. A catalyst containing 3 to 5% cupric oxide on pumice stone was found to be satisfactory for the process. The effects of temperature, period of reaction and concentration of ethylene glycol and oxygen on the yield and conversion to glyoxal were studied, and the most suitable conditions were determined for the process. Carbon dioxide and formaldehyde were the major by-products in the reaction. Formaldehyde was formed mainly due to the homogeneous reactions of ethylene glycol with oxygen in the void space of the reactor. The formation of glyoxal and carbon dioxide were correlated by suitable empirical rate expressions.