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71.
水热合成杂原子B-Beta分子筛,低温氮化二次处理制备N掺杂的新型碱催化剂,利用Knoevenagel缩合反应进行碱性催化性能评价,考察氮化温度、反应时间、不同氮化前驱体及催化剂稳定性对反应的影响.结果表明,采用低温500℃氮化处理的杂原子B-Beta分子筛催化剂具有优异的催化活性,苯甲醛转化率及产物选择性均接近100... 相似文献
72.
Hydrothermal treatment of Co/MFI catalysts at high temperature increases their performance for NO
x
reduction with methane. As this treatment also shifts the TPR peak of isolated Co ions upward by 20 °C, the results suggest that the hydrothermal treatment induces transport of Co2+ ions from to positions. 相似文献
73.
实验以MgO/MCM-22为催化剂,在气相连续流动固定床反应器上催化苯与草酸二乙酯(DEO)烷基化,合成乙苯(EB)。考察了MgO负载量变化和工艺条件的影响。以硝酸镁为前驱体通过等体积浸渍法制备了MgO/MCM-22催化剂,并以低温N_2吸附脱附、X射线衍射、NH_3-TPD、吡啶吸附IR等,对催化剂进行了表征。实验结果表明:随MgO负载量的增加,苯的转化率逐渐下降,而乙苯的选择性明显提高,这主要是由于负载MgO后催化剂的酸性位数量下降引起的。以MCM-22为催化剂,在最佳反应条件下:温度653 K,空速为2 h~(-1),原料配比n(苯):n(DEO)=4:1,苯的转化率为37.5%,乙苯选择性为80.3%。 相似文献
74.
沸石抗菌剂的研究现状与展望 总被引:1,自引:0,他引:1
介绍了目前国内外沸石抗菌剂的研究现状,重点讨论了沸石抗菌剂的原料改性、抗菌机理、持久性、变色抑制性、结构化等方面的特点,简述了沸石抗菌剂在日常生活中的应用,并对沸石抗菌剂的发展方向进行了展望. 相似文献
75.
《Journal of Nuclear Science and Technology》2013,50(4):435-441
The pressure swing adsorption (PSA) method, operating rapid desorption, has become applied to medium-massive air-component separation. In this study, with the aim of applying the PSA method to a hydrogen isotope separation process, the multi-component adsorption characteristics of H2-D2 or H2-HD-D2 on a synthetic zeolite at the liquid nitrogen temperature 77.4 K are investigated by using a volumetric apparatus, where the system effects of thermal transpiration and diffusion are taken into account. The adsorption isotherms for pure H2 and D2 are shown in a wide pressure range between 10-2 and 105Pa. The isotherms are closely approximated by an error functional expression proposed here. The separation factors resulting in adsorption are measured in a wide range of amount adsorbed. The separation factors of D2/H2 are estimated in accordance with the ideal adsorbed solution theory using the adsorption isotherms for H2 and D2. The behavior of the estimated factors agrees with that of the experimental ones. The result suggests that values around 3 are expectable for the factors of D2/H2 at amounts adsorbed roughly between 0.01 and 1 mol/kg. 相似文献
76.
77.
The adsorption of nitrogen oxides on Cu-ZSM-5 was studied by infrared spectroscopy to elucidate the species associated with the band at 2133 cm–1. The band was found for both NO and NO2 adsorption. Labeling experiments with15NO revealed that the associated surface species contained nitrogen and, most likely, an N-O bond. Co-adsorption experiments of NO and oxygen produced adsorbed nitronium, NO
2
+
, as the principal, associated species. Adsorption of nitrogen oxides on dispersed CuO and the HZSM-5 support demonstrated that the 2133 cm–1 band was not necessarily associated with copper ions. A relatively strong correlation between the bands at 2133 and 3615 cm–1 indicates that the primary adsorption sites of NO
2
+
are the strongly protic, bridging Si(OH)Al framework hydroxyls. Once these were filled, other, weaker acid sites began to adsorb NO
2
O
. 相似文献
78.
CO hydrogenation over Mn promoted Rh/NaY catalysts was studied at 10 bar and 250°C. Significant selectivity to oxygenates, mainly ethanol and ethyl acetate, was obtained after neutralizing the protons that are formed during reduction of Rh ions. Layered bed experiments show that protons act as sites catalyzing secondary reactions. Protons also convert Mn(OH)2 to Mn2+ ions; the catalysts with highest selectivity to oxygenates contain MnO particles and Rh clusters. The results suggest chemical interaction of adsorbates on Rhn clusters with those on MnO. 相似文献
79.
80.