正己烷异构化非贵金属催化剂的研究

本文首次将活性组分磷引入了正已烷异构化非贵 金属Ｎｉ－Ｍｏ／ＨＺＳＭ－５催化剂上,采用高压微反－色谱装置分别考察了Ｎｉ／ＨＺＳＭ－５、Ｎｉ－Ｍｏ／ＨＺＳＭ－５、Ｎｉ－Ｍｏ－Ｐ／ＨＺＳＭ－５催化剂的民构化性能。在空速为２ｈ＾－１,氢烃摩尔比为８．０,压力为１．５ＭＰａ,反应温度为２３０℃的条件下,当Ｎｉ含量为１．０％、Ｍｏ含量为２．０％、Ｐ含量为１．５％时,催化剂的异构化收率、选择性和转化率分别高达     

稀士助剂Y对甲烷芳构化反应催化剂Y—Mo／HZSM—5表面性质的影响

用吡啶－ＴＰＤ实验和异丙醇分解反应研究了稀土助剂Ｙ对甲烷芳构化反应催化剂Ｍｏ／ＨＺＳＭ－５表面性质的影响，说明了稀土Ｙ对Ｍｏ／ＨＺＳＭ－５催化剂的添加增强了催化剂表面的酸性，从而促进了甲烷的活化，提高了甲烷转化率。     

无机氟改性的HZSM—5分子筛催化1,2,4—三甲苯与甲醇烷基化合成…

用不同浓试的ＮＨ４Ｆ对ＨＺＳＭ－５分子筛进行改性制成偏三甲苯－甲醇烷基化反应的催化剂，考察反应时间、改性剂浓度、焙烧温度对其催化性能的影响。结果发现，无机氟改性使ＨＺＳＭ－５分子筛对偏三甲苯－甲醇烷基化合成均四甲苯反应的活性、选择性及催化剂的稳定性都有良好的促进作用，并且改性后的ＨＺＳＭ－５分子筛加入结合剂制成的催化剂仍具有良好的催化性能。采用ＳＥＭ、ＩＲ及ＴＰＤ等方法测试无机氟改性后ＨＺＳＭ－５     

HZSM—5沸石分子筛催化合成乙酸异戊酯的研究

以ＨＺＳＭ－５沸石分子筛为催化剂，应用常压液固相酯化反应合成了乙酸异戊酯。考察了催化剂用量，醇酸比，反应温度和反应时间对酯产率的影响，结果表明，ＨＺＳＭ－５用量为２克，异戊醇／乙酸为１／２．５（ｍｏｌ比）反应温度为１３０～１４０℃，反应时间为３小时，酯产率８４％。     

无机氟改性的HZSM－5分子筛催化1，2，4－三甲苯与甲醇烷基化合成1，2，4，5－四甲苯的研究

用不同浓度的ＮＨ_４Ｆ对ＨＺＳＭ－５分子筛进行改性制成偏三甲苯－甲醇烷基化反应的催化剂,考察反应时间、改性剂浓度、焙烧温度对其催化性能的影响。结果发现,无机氟改性使ＨＺＳＭ－５分子筛对偏三甲苯－甲醇烷基化合成均四甲苯反应的活性、选择性及催化剂的稳定性都有良好的促进作用,并且改性后的ＨＺＳＭ－５分子筛加入粘合剂制成的催化剂仍具有良好的催化性能。采用ＳＥＭ、ＩＲ及ＴＰＤ等方法测试无机氟改性后ＨＺＳＭ－５分子筛结构及酸性的变化。     

甲醇制二甲醚用铝基催化剂的制备及其性能研究

研制出以氧化铝为载体的催化剂Ａ以及添加第ＩＶ副族元素的催化剂Ａ＋Ｂ，并与ＨＺＳＭ－５催化剂进行了活性对比。催化剂Ａ经１０００ｈ原粒度测试，结果表明：在反应温度３００℃，空速４．２５～４．５０ｈ－１，压力为常压的条件下，二甲醚选择性＞９９％，甲醇转化率≥８０％。     

HXSM-5沸石分子筛催化合成乙酸异戊酯的研究

以ＨＺＳＭ－５沸石分子筛为催化剂,应用常压液固相酯化反应合成了乙酸异戊酯。考察了催化剂用量,醇酸比、反应温度和反应时间对酯产率的影响。结果表明,ＨＺＳＭ－５用量为２克,异戊醇／乙酸为１／２．５（ｍｏｌ比）,反应温度为１３０～１４０℃,反应时间为３小时,酯产率８４％。     

用~(31)P-NMR谱法分析硫化二硫代磷酸钼摩擦改进剂的组分

报道了关于３１Ｐ ＮＭＲ谱法分析不同反应条件下所制得硫化二硫代磷酸钼（Ｓ ＭｏＤＴＰ）摩擦改进剂的组分及其变化。结果表明，所合成８种Ｓ ＭｏＤＴＰ产物均是由１２～１３个有机５价Ｍｏ—Ｓ、ＰＳ、ＰＯ化合物及有机３价Ｐ—Ｓ化合物组成的混合物，其中随着反应温度从３０℃升至１００℃，或者随着Ｐ／Ｍｏ摩尔比从２／１降至１．２／１，或者随着预通Ｈ２Ｓ时间从０增至４５ｍｉｎ，其Ｓ ＭｏＤＴＰ产物中所含有机５价Ｍｏ—Ｓ化合物的含量（ｗ）分别从２８．９％、４２．４％和３７．２％增至５２．５％、５２．７％和４２．４％。     

工业芳构化催化剂中γ－Al_2O_3对分子筛酸性的影响

用重量吸附法测得ＨＺＳＭ－５分子筛原粉、γ－Ａｌ２Ｏ３和工业用芳构化催化剂ＨＺＳＭ－５的酸量和强度。实验发现ＨＺＳＭ－５原粉和工业催化剂的酸量很接近，而Ａｌ２Ｏ３的酸量要比原粉低得多，强酸只占原粉的１０％左右。用红外吸附法测得原粉的Ｂ酸／Ｌ酸相对含量为催化剂的４倍左右，实验表明，Ａｌ２Ｏ３对分子筛的酸性有较大影响，主要增加了Ｌ酸。     

Mo／HZSM—5分子筛催化合成乳酸酯的研究

利用Ｍｏ／ＨＺＳＭ－５分子筛催化剂，合成了六种乳酸酯，考察了催化剂用量，酸醇比，带水剂用量及反应时间等因素对反应的影响，结果表明，在适宜的反应条件下，乳酸酯的产率在８５％以上，且高碳醇的酯产率高于低碳醇的酯产率，正碳醇的酯和率高于仲碳醇的酯产率。     

Methane activation without using oxidants over Mo/HZSM-5 zeolite catalysts

The effect of Mo loading, calcination temperature, reaction temperature and space velocity on the catalytic performance of methane dehydrogenation and aromatization without using oxidants over Mo/HZSM-5 has been studied. The XRD and BET measurements show that Mo species are highly dispersed in the channels of the HZSM-5 zeolite, resulting from the interaction between the Mo species and the zeolite, which also leads to a decrease in its crystallinity. The Brønsted acidity, the channel structure and the state and location of Mo species in the zeolite seem to be crucial factors for its catalytic performance. It was found that 2% Mo/HZSM-5 calcined at 773 K showed the best aromatization activity among the tested catalysts, the methane conversion being 9% at 1013 K with the selectivity to aromatics higher than 90%. The experimental results obtained from the variation of space velocity gave evidence that ethylene is an initial product. On the basis of these results a possible mechanism for methane dehydrogenation and aromatization has been proposed in which both the heterolytic splitting of methane in a solid acid environment and a molybdenum carbene-like complex as an intermediate are of significance.     

甲烷芳构化反应催化剂Ｍｏ-Ｍ／ＨＺＳＭ-５表面性质的研究

对甲烷芳构化催化剂Ｍｏ-Ｍ／ＨＺＳＭ-５进行了异丙醇分解、ＮＨ３-ＴＰＤ-ＭＳ、积炭量测定表征,其结果均与芳构化性能有关。芳烃收率高,稳定性好,积炭量较少,而且具有相当量的酸量和一定量强酸量及较强的脱氢中心。     

Mo/HZSM-5上甲烷无氧芳构化催化剂制备因素的考察

采用Mo/HZSM-5作为甲烷无氧芳构化催化剂,考察了催化剂制备部分影响因素.结果表明,采用较低的nSi:nAl时(25)载体制备的催化剂活性和稳定性较好;浸渍法优于固相反应法;Mo担载的质量分数为4%时,催化剂表现出最高活性;分子筛预先经碱处理,能够明显改善催化剂稳定性.     

稀土助剂Y对甲烷芳构化反应催化剂Y-Mo/HZSM-5表面性质的影响

用吡啶 -TPD实验和异丙醇分解反应研究了稀土助剂Y对甲烷芳构化反应催化剂Mo/HZSM - 5表面性质的影响 ,说明了稀土Y对Mo/HZSM - 5催化剂的添加增强了催化剂表面的酸性 ,从而促进了甲烷的活化 ,提高了甲烷转化率。     

Non-oxidative conversion of methane to aromatics over modified Mo/HZSM5 catalysts

The effects of HZSM5 Si/Al ratio, cobalt additive and HCl-acidified pretreatment on methane conversion and selectivity to aromatics have been investigated for non-oxidative conversion of methane to aromatics. The HZSM5 (E) with low Si/Al ratio (Si/Al=20) has better methane conversion and benzene selectivity than HZSM5 (D) (Si/Al=55). The synergistic effect is exhibited in 3% Mo-1% Co-HCl/HZSM5 (E) catalyst, on which a high methane conversion of 10.7% can be achieved, in comparison with 5.3% methane conversion on 3% Mo/HZSM5 (E). The catalysts have been characterized by XPS and the reaction mechanism is discussed.     

正己烷在Zn/HZSM-5上芳构化反应机理的探讨

比较了正己烷在HZSM-5、Al₂O₃和ZnO/Al₂O₃催化剂上的反应性能，探讨了锌含量和水热处理对Zn/HZSM-5芳构化性能的影响。发现B酸是芳构化反应不可缺少的活性中心，Zn-L因其氢解作用促进烃类的活化和脱氢，Al-L酸只是对正己烷有较弱的活化作用。提出了正己烷在Zn/HZSM-5上的芳构化反应机理。     

Highly Stable Performance of Methane Dehydroaromatization on Mo/HZSM-5 Catalyst with a Small Amount of H2 Addition into Methane Feed

With a small amount of H₂ (3 6%) addition into methane feed, coke formation on 6 wt% Mo catalyst during the methane dehydroaromatization reaction was effectively suppressed and the catalyst stability was increased evidently under the reaction conditions of 1023K, 0.3MPa and 2520 mL g-MFI^-1 h^-1 of methane space velocity.     

Methane aromatization using Mo-based catalysts prepared by microwave heating

Mo/HZSM-5 and Cu–Mo/HZSM-5 catalysts for the non-oxidative aromatization of methane have been prepared by microwave heating method. The effects of Mo loading, the molar ratio of Cu/Mo and preparation method on the catalytic performance of catalysts were studied. The results were compared with those for the methane aromatization over catalysts prepared by conventional heating. Both two kinds of catalysts have the maximum methane conversion when the Mo loading is 6%. The catalysts prepared by microwave heating exhibited higher selectivity to benzene than that prepared by conventional heating. The addition of metal Cu to Mo/HZSM-5 catalyst prepared by microwave heating enhanced the lifetime of catalyst, and gave rise to a little increase in methane conversion. The molar ratio of Cu/Mo influenced the methane conversion, and the maximum value was attained when Cu/Mo = 0.05, whereas no significant influence on the benzene selectivity was observed with the increase molar ratio of Cu/Mo. N₂ adsorption results showed that the catalysts prepared by microwave heating have the larger surface area and the similar pore volume compared with the catalysts prepared by conventional heating. This fact revealed that the more Mo species located on the outer surface of catalysts prepared by microwave heating is the main reason why they have better catalytic performance. XRD analysis indicated that the Mo species are highly dispersed on HZSM-5 zeolite. The addition of Cu influenced the dispersion. The actual active phase Mo₂C can be identified on the catalyst surface after reaction. TEM analysis revealed the carbonaceous deposition to have the form of carbon nanotube after reaction, with a uniform size range of 10–20 nm. TG analysis indicated that carbonaceous deposition on the catalysts prepared by microwave heating is lower than that by conventional heating, and the metal Cu further prompts the stability of catalyst. Most of the carbonaceous deposition on catalysts prepared by microwave heating is formed at low temperature and it is easy to burn-off. Coke accumulation at high temperature is the main reason of catalyst deactivation. The carbonaceous deposition formed on the catalysts for non-oxidative aromatization of methane is different from those formed on the catalysts for partial oxidation of methane.     

Bifunctional Catalysis of Mo/HZSM-5 in the Dehydroaromatization of Methane to Benzene and Naphthalene XAFS/TG/DTA/MASS/FTIR Characterization and Supporting Effects

The direct conversion of methane to aromatics such as benzene and naphthalene has been studied on a series of Mo-supported catalysts using HZSM-5, FSM-16, mordenite, USY, SiO₂, and Al₂O₃as the supporting materials. Among all the supports used, the HZSM-5-supported Mo catalysts exhibit the highest yield of aromatic products, achieving over 70% total selectivity of the hydrocarbons on a carbon basis at 5–12% methane conversion at 973 K and 1 atm. By contrast, less than 20% of the converted methane is transformed to hydrocarbon products on the other Mo-supported catalysts, which are drastically deactivated, owing to serious coke formation. The XANES/EXAFS and TG/DTA/mass studies reveal that the zeolite-supported Mo oxide is endothermally converted with methane around 955 K to molybdenum carbide (Mo₂C) cluster (Mo-C, C.N.=1,R=2.09 Å; Mo-Mo, C.N.=2.3–3.5;R=2.98 Å), which initiates the methane aromatization yielding benzene and naphthalene at 873–1023 K. Although both Mo₂C and HZSM-5 support alone have a very low activity for the reaction, physically mixed hybrid catalysts consisting of 3 wt% Mo/SiO₂+HZSM-5 and Mo₂C+HZSM-5 exhibited a remarkable promotion to enhance the yields of benzene and naphthalene over 100–300 times more than either component alone. On the other hand, it was demonstrated by the IR measurement in pyridine adsorption that the Mo/HZSM-5 catalysts having the optimum SiO₂/Al₂O₃ratios, around 40, show maximum Brönsted acidity among the catalysts with SiO₂/Al₂O₃ratios of 20–1900. There is a close correlation between the activity of benzene formation in methane aromatization and the Brönsted acidity of Mo/HZSM-5, but not Lewis aciditiy. It was found that maximum benzene formation was obtained on the Moz/HZSM-5 having SiO₂/Al₂O₃ratios of 20–49, but substantially poor activities on those with SiO₂/Al₂O₃ratios smaller and higher than 40. The results suggest that methane is dissociated on the molybdenum carbide cluster supported on HZSM-5 having optimum Brönsted acidity to form CH_x(x>1) and C₂-species as the primary intermediates which are oligomerized subsequently to aromatics such as benzene and naphthalene at the interface of Mo₂C and HZSM-5 zeolite having the optimum Brönsted acidity. The bifunctional catalysis of Mo/HZSM for methane conversion towards aromatics is discussed by analogy with the promotion mechanism on the Pt/Al₂O₃catalyst for the dehydro-aromatization of alkanes.     

玄武岩催化甲烷裂解制 C2 烃

以天然玄武岩为甲烷裂解催化剂,通过XRF、XRD、SEM及XPS对催化剂组成、结构、表面活性物种进行了研究。利用固定床反应装置考察了不同反应温度、空速条件下玄武岩催化甲烷裂解制C_2烃的效果。结果表明,在气体空速为4 L·h-1条件下,当反应温度为1 225 K时,甲烷的转化率为7.66%,C_2烃的选择性为33.64%;当反应温度升至1 325 K时,甲烷的转化率可达17.13%,同时C_2烃的选择性为27.21%。相同温度下,气体空速越大,乙烷的选择性越高,乙炔的选择性越低。催化剂活性因表面积炭的产生而降低,积炭类型为芳烃积炭。