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81.
Synthesis of oleyl oleate as a jojoba oil analog 总被引:2,自引:0,他引:2
N. Sánchez M. Martinez J. Aracil A. Corma 《Journal of the American Oil Chemists' Society》1992,69(11):1150-1153
Synthesis of a wax ester analog of jojoba oil was accomplished from oleic acid and oleyl alcohol with a zeolite as catalyst.
A full 23 factorial design at two levels has been used in the synthesis. The variables selected were temperature, reduced pressure
and initial catalyst concentration. The most important variable within the range studied was temperature. Reduced pressure
had a negative influence, and initial catalyst concentration showed a positive influence on the process. A response equation
has been determined for the yield of ester. The properties of the synthesized product are similar to those of natural jojoba
oil. 相似文献
82.
引 言2 ,6 二甲基萘 (2 ,6 DMN)是生产新型高性能聚酯材料聚萘二甲酸乙二醇酯 (PEN)的重要原料 .目前已工业化的邻二甲苯与丁二烯烷基化生产2 ,6 DMN路线生产步骤多 ,工艺过程复杂 ,生产成本高 ,制约了PEN的发展[1,2 ] .HZSM 5沸石是一种具有强酸性、高硅铝比和独特孔道结构的分子筛 ,对许多正碳离子反应有良好的择形催化性能[3] .HZSM 5催化甲基萘 (DMN)与甲醇烷基化合成 2 ,6 DMN路线工艺过程简单 ,产品选择性高 ,是一条具有发展前景的技术路线[4 ] .然而 ,在常压下进行烷基化反应时 ,反应活性低 ,催化剂容易因结焦而失去原有的活性[5~ 7] .超临界流体具有良好的溶解和扩散性能 .在超临界条件下进行的化学反应不仅可以提高催化剂的反应活性 ,而且还可以原位维持非均相催化剂的活性 ,延长催化剂的寿命[8,9] .本文正是基于超临界流体独特的性质 ,探索在超临界条件下甲基萘与甲醇烷基化反应中提高反应活性和延长催化剂寿命的可能性 .1 实验部分1 1 催化剂的制备NaZSM 5沸石 (硅铝比为 38)由南开大学催化剂厂提供 .在 80℃下用 1mol... 相似文献
83.
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86.
Effectiveness of microwave heating in an activation treatment of zeolites was studied and utilization of zeolites for reusable desiccant was examined. X zeolite was chosen as a target material for its large adsorption capacity. Na-X zeolite easily caused a thermal runaway by microwave radiation of 500 W but Ca contained X zeolite merely reached ca. 573 K under the same conditions. Mixtures of Na-X and Ca-X with suitably mixed ratios did not cause the thermal runaway and their heating temperatures were controlled (>573 K) at will. Under the most suitable conditions, the mixture reached a dehydration degree of 92%. A degradation degree of adsorptive capacity of the mixture for water was examined after three treatments. The average degradation degree was 1.5% per treatment. The heating method is promising as a quick and easy technique to activate zeolite. By applying the method, the zeolites with suitable mixing ratios are usable as a reusable desiccant for home use. 相似文献
87.
The physicochemical features of phosphorus-modified ZSM-5 zeolites (SiO2/Al2O3 molar ratio is 25) were characterized by XRD(X-ray diffraction), BET(Brunauer, Emmett and Teller spcific surface area measurement), NH3-TPD(ammonia temperature-programmed desorption) and MASNMR(magic angle spinning nuclear magnetic resonance), and the performance on catalytic pyrolysis to produce ethylene was investigated with a light hydrocarbon fixed bed micro-reactor with n-octane as feed. The results show that the acid site density, acid intensity and hydrothermal stability of ZSM-5 zeolite were improved by phosphorus modification. When P205 content in ZSM-5 zeolite is higher than 2.5%, phosphorus modification can prevent ZSM-5 zeolite crystal structure transformation from orthorhombic to monoclinic. In addition, the dealumination of ZSM-5 zeolite framework was moderated by phosphorus modification under high temperature hydrothermal treatment. The results of n-octane pyrolysis on phosphorus-modified ZSM-5 zeolites show that ethylene yields of zeolites with different phosphorus content are almost the same under the same n-octane conversion. However, the modified zeolites with higher pyrolysis activity give lower yield of propene, butene and total olefin than lower pyrolysis activity under the same n-octane conversion. 相似文献
88.
Kwang‐Jea Kim Sangmin Kwon Hyun Kim Patit P. Kundu Yong‐Wook Kim Yong‐Keun Lee Kyu Jong Lee Byung H. Lee Soonja Choe 《应用聚合物科学杂志》2003,87(2):311-321
The mixing cycle‐dependent degree of dispersion and degree of mixing of a calcite (calcium carbonate) agglomerate in high‐density polyethylene (HDPE), low‐density polyethylene (LDPE), and linear low‐density polyethylene (LLDPE) matrices upon stretching was investigated using three different techniques: mechanical property, morphological behavior, and image analyzer analyses. The mechanical properties analyzed in terms of the tensile strength and maximum elongation resulted in that the second mixing was the best for giving a better property for all systems except the LDPE system, which exhibited no significant difference between the second and third mixings. The morphological behavior of the three compounds were different, but no distinctive difference was observed to differentiate the degree of mixing from system to system. The number‐, weight‐, and z + 1‐average diameters of the air hole and the aspect ratio upon the stretching and mixing cycle were calculated to analyze the degree of mixing of the calcite‐filled composites. As a consequence, no difference in the average diameter of the air hole was obtained among the three systems, but the aspect ratios of the air hole varied significantly. Thus, the degree of dispersion and the degree of mixing may be influenced by the average calcite agglomerate size, the average diameter of the air hole, and the aspect ratio upon stretching and mixing cycles. Those factors would be formed by the difference in chemical characteristics upon various microstructures of polyethylene and its molecular weight and molecular weight distribution. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 87: 311–321, 2003 相似文献
89.
Adsorption dynamics of ethane in two granular fixed beds and structured fixed beds with microfibrous composites was studied. 5A zeolite membrane 5A/PSSF(paper-like sintered stainless steel fiber) and microfibrous entrapped activated carbon(MEAC) composites were prepared by wet layup papermaking/sintering technique and in-situ hydrothermal method. Microfibrous composites were characterized by X-ray diffraction, scanning electron microscopy and N2 adsorption/desorption. Structured fixed... 相似文献
90.
Abdolhamid Zare Parviz Darvishi Asghar Lashanizadegan Mohammad M. Zerafat 《加拿大化工杂志》2023,101(7):3925-3936
Today, CO2 separation is very important, both as an environmental issue and also in various industries. In this study, the water-based nanofluid of NaP zeolite nanocrystals and 1-dodecyl-3-methylimidazolium chloride ([C12mim][Cl]) ionic liquid were mixed and tested experimentally for CO2 absorption in an isothermal high pressure cell equipped with magnetic stirring. Zeolite nanocrystals were synthesized via the hydrothermal approach and characterized. A series of experiments were performed at different conditions to investigate the impact of various parameters, including nanoparticle type, nanoparticle concentration, stabilizer concentration, and the vessel's initial pressure, on CO2 solubility. It was found that 0.02 wt.% of zeolite nanoparticles, 0.4 wt.% of [C12mim][Cl] ionic liquid, and 0.05 wt.% of sodium dodecyl benzene sulphonate (SDBS) in nanofluids result in higher absorption of CO2 compared to other concentrations. Furthermore, CO2 absorption was increased by increasing ionic liquid and surfactant concentration up to a certain value near critical micelle concentration, but after that the CO2 absorption was decreased. The overall CO2 absorption enhancement at 20 bar for 0.02 wt.% zeolite and ZnO water-based nanofluids with 0.4% [C12mim][Cl] ionic liquid and 0.02 wt.% SDBS were 26.9%, 21.5%, 21.2%, and 17% in comparison to pure water, respectively. In an absorption process using nanofluids, besides the influence of the mentioned parameters, the micro-convection caused by Brownian motion and the grazing effect of nanoparticles should be noted. Considering the micro-convection and grazing effects, a theoretical model should take into account the Brownian motion and grazing effects on the mass transfer rate in nanofluids to investigate the absorption enhancement by nano-particles. 相似文献