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催化新材料—钛硅分子筛的制备与应用 总被引:5,自引:0,他引:5
对具有独特氧化性能的含钛分子筛的制备和应用进行了述评,简述了TS-1,TS-2,Ti-MCM-4,Ti-HMS,Ti-β型等含钛分子筛的合成及合成中不同的硅源,钛源,模板剂,合成条件对结构性能的影响。介绍了含钛分子筛在苯与苯酚的羟基化,烯烃的环氧化,环己酮的肟化,妥和饱和烃的氧化等反应中的应用及催化的作用机理,并对钛硅分子筛研究中存在的问题和应用前景提出了看法。 相似文献
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以全硅分子筛silicalite-1为硅源,利用水热晶化法合成表面富钛的钛硅分子筛CTS,采用XRD、N2吸附-脱附、IR、XRF、UV—vis、XPS、DTA—TGA和SEM等对合成的分子筛进行表征。结果表明,合成的钛硅分子筛CTS具有MFI拓扑结构,钛物种主要集中在其表面,催化性能评价表明,在苯酚羟基化探针反应中合成的钛硅分子筛CTS具有较好的活性和苯二酚选择性,重复使用次数优于常规利用硅酯为硅源合成的分子筛TS-1。 相似文献
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对钛硅分子筛TS 1微粉催化剂应用动态过滤技术 ,在动态旋叶压滤机上进行了过滤性能的研究 ,得到了过滤速率随时间的变化规律 ,并分析了操作压力对过滤速率的影响。为了结合实际工业生产的要求 ,对过滤介质进行了再生实验。该研究为TS 1微粉催化剂的过滤分离提供了一个可行的方法 ,为确定适宜的操作条件及工业应用提供了实验依据 相似文献
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采用液固相同晶取代法和微波法合成了Ti-β,Ti-NaY和Ti-MCM-41a,并通过红外和紫外-可见漫射对样品进行表征。以二苯并噻吩为研究对象,考察了钛硅分子筛的光催化活性。结果发现,钛硅分子筛具有很好的光催化性能,光催化氧化脱硫的活性顺序为:Ti-MCM-41a>TS-1>Ti-NaY>Ti-β。10 mL模型油为基准的最佳反应条件为:钛质量分数,Ti-β为0.37%,Ti-NaY为3.7%和Ti-MCM-41a为5.325%;催化剂用量,Ti-NaY为0.05 g,Ti-β为0.05g,Ti-MCM-41a为0.04 g,H2O2用量(氧硫摩尔比):Ti-NaY为5.33∶1,Ti-β和Ti-MCM-41为12.39∶1。 相似文献
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以无机陶瓷管为支撑体、热塑性酚醛树脂为原料,经高温炭化制备了炭分子筛膜。用低温N2吸附的方法测定了炭分子筛膜的比表面积,用扫描电子显微镜对膜的形貌和厚度进行了表征。考察了膜的气体透过率以及气体的理想选择性随温度的变化关系:H2、CO2、O2、N2和CH4的透过率随温度的升高而增大;理想选择性α(H2/N2)、α(CO2/N2)、α(CO2/CH4)随温度的升高而减小,而α(O2/N2)随温度的升高先增大后减小,在90℃左右气体选择性达到最大。最后由阿累尼乌斯公式计算了气体透过炭分子筛膜的活化能,进一步说明气体透过机理为活化扩散。 相似文献
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Xiaoli Ma Y. S. Lin Xiaotong Wei Jay Kniep 《American Institute of Chemical Engineers》2016,62(2):491-499
Ultrathin (down to 300 nm), high quality carbon molecular sieve (CMS) membranes were synthesized on mesoporous γ‐alumina support by pyrolysis of defect free polymer films. The effect of membrane thickness on the micropore structure and gas transport properties of CMS membranes was studied with the feed of He/N2 and C3H6/C3H8 mixtures. Gas permeance increases with constant selectivity as the membrane thickness decreases to 520 nm. The 520‐nm CMS membrane exhibits C3H6/C3H8 mixture selectivity of ~31 and C3H6 permeance of ~1.0 × 10?8 mol m?2 s?1 Pa?1. Both C3H8 permeance and He/N2 selectivity increase, but the permeance of He, N2, and C3H6 and the selectivity of C3H6/C3H8 decrease with further decrease in membrane thickness from 520 to 300 nm. These results can be explained by the thickness‐dependent chain mobility of the polymer film which yields thinner final CMS membranes with reduction in pore size and possible closure of C3H6‐accessible micropores. © 2015 American Institute of Chemical Engineers AIChE J, 62: 491–499, 2016 相似文献
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A. M. Al-Damkhi R. S. Al-Ameeri G. V. Jeffreys C. J. Mumford 《Journal of chemical technology and biotechnology (Oxford, Oxfordshire : 1986)》1987,37(4):215-228
A study has been made of the vapour-phase adsorptive separation of n-alkanes from Kuwait kerosene using zeolite molecular sieves (LMS-5A). The object was to identify the optimum operating conditions, in terms of flow rate, adsorption temperature and zeolite particle size for the separation of n-alkanes from kerosene, so that the remaining stock would also be of marketable quality. The effect of these conditions on the height of the mass transfer zone (HMTZ) and the dynamic capacity (Ad) of zeolite was also investigated. The adsorptive separation process comprised one cycle of adsorption using a fixed bed of zeolite type-5A. The bed was fed with kerosene vapour until equilibrium had been achieved, whereby the n-paraffins were adsorbed and the denormalized material excluded. The processes were carried out isobarically at one atmosphere. The optimum operating conditions were found to be a feed flow rate of 33.33 × 10?9 m3 s?1, an adsorption temperature of 643 K and a zeolite pellet fraction size of 1.0–2.0 × 10?3m. This yielded an HMTZ value of 0.206 m and an Ad of 9.653 × 10?2 kg n-paraffins kg?1 zeolite. The data will serve as a basis for the design of commercial plant. 相似文献
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碳分子筛变压吸附空气分离活性及表征 总被引:1,自引:0,他引:1
石油焦基活性炭经Ni(NO3)2溶液室温浸渍过夜,红外灯缓慢烘干(Ni载持量5%),再经1-丁烯沉积处理,制备了催化炭沉积碳分子筛S-CMS,探讨了空气进料流量、压力和再生时间对碳分子筛空分效果的影响。结果表明,当流量为10~50 mL/min时,对空气分离效果影响很小;当吸附压力增加时,氮气浓度应该是增加的。脱附时间大于60 s时,S-CMS能够被再生。与商用T1-CMS比较,S-CMS是优秀的,在常温常压下,可获得浓度为93%的富氮气体。通过对碳分子筛表面结构的FT-IR、骨架结构-XRD及其氧化性in-situ TG/DTA的测试显示,S-CMS具有微孔分布独特的骨架网络结构,是一种潜在的优越变压吸附剂。 相似文献
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Carbon molecular sieving membranes are new, high-performance materials for gas separations. The selectivities of these membranes are much higher than those typically found with polymeric materials and the selectivities are achieved without sacrificing productivity. Ultramicroporous carbon membranes can be produced by pyrolyzing various thermosetting polymeric materials under a variety of pyrolysis conditions. The membranes described in this paper were produced from the pyrolysis of a hollow-fiber polyimide precursor under conditions found to yield membranes with good air separation properties. Membranes were produced by two different temperature protocols, and were evaluated with mixed gas feeds at pressures ranging up to 200 psig (1.48 MPa). The lower temperature protocol yielded membranes with
selectivities ranging from 8.5 to 11.5, and a higher temperature pyrolysis yielded membranes with selectivities ranging from 11.0 to 14.0. These membranes were found to be quite stable over time periods of several days with high-purity, dry feeds. Limited studies also showed that these membranes were highly effective for the separation of other mixed gas pairs, including
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通过变温陈化步骤,采用水热结晶法制备TS-1分子筛。改变陈化步骤,得到一系列粒径不同的TS-1分子筛,并探究粒径对丙烯醇环氧化反应催化性能的影响。采用FT-IR、UV-Vis、BET、XRD和SEM等表征TS-1分子筛催化剂晶相,结果表明,不同条件制得的TS-1分子筛具有相同的MFI结构,Ti大部分以骨架钛形式存在,也有少量锐钛矿相Ti O2存在。随着反应温度的升高,TS-1粒径逐渐增大。通过后续催化反应发现,TS-1分子筛催化剂的催化活性改变不大,这可能是由于催化剂中活性位点的数目变化不大。从催化剂分离实验可以看出,随着粒径的增大,催化剂回收率从82.4%增至95.3%。 相似文献