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1.
液相烷基化制异丙苯MP-01催化剂的性能 总被引:1,自引:1,他引:0
研究了反应温度、反应时间、丙烯空速和苯烯比等工艺参数对催化剂MP-01反应性能的影响.结果表明,170 ℃以下,反应温度和丙烯转化率存在线性关系,温度越高,反应速率越快,丙烯转化率越高;降低丙烯空速,丙烯转化率提高;苯烯比和异丙苯选择性存在线性关系,苯烯比越高,异丙苯的选择性越高;在苯烯比为2.0 ~8.0,随苯烯比的提高,丙烯转化率先降低然后再升高,丙烯转化率随反应时间延长而下降.产物中正丙苯含量和反应温度成正比,温度越高,生成正丙苯的速率越快,生成量越多.生成异丙苯和正丙苯的活化能分别为26 kJ/mol和42 kJ/mol,因此高温有利于正丙苯的生成. 相似文献
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以工业应用的HZSM-5为催化剂,在连续固定床反应器中考察了反应温度和甲醇分压对甲醇制丙烯反应产物的影响,发现当温度大于450℃时,随着温度的升高,甲醇的转化率都能达到99%以上,乙烯和丙烯的总选择性增加,低碳烷烃选择性增加,高碳产物选择性下降;随着甲醇分压降低,甲醇转化率下降,产物丙烯/乙烯质量比(P/E比)增加,丙烯在甲醇分压为33 kPa时达到最高值,而当分压极低时,催化剂快速失活。从转化率、丙烯选择性、P/E比以及低碳烯烃产物选择性等多方面综合考虑,甲醇转化制丙烯的反应温度优选470℃,并建议甲醇分压为33 kPa。 相似文献
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HZSM-5催化剂上甲醇制丙烯反应条件的研究 总被引:1,自引:0,他引:1
以HZSM-5分子筛为催化剂,在固定床反应器中考察了反应温度和原料空速对甲醇制丙烯性能的影响。结果表明,随着反应温度的升高,乙烯和丙烯选择性均增加,但温度过高容易引起催化剂的失活;而随原料空速的增大,甲醇转化率、乙烯和丙烯的选择性均呈下降趋势。最佳的反应条件为反应温度为460°C,原料液时空速为1.4 kg(Methanol)/kg(cat.).h。对添加粘结剂与未添加粘结剂成型后的催化剂性能比较,表明添加粘结剂成型后,甲醇转化率和丙烯选择性有所下降。 相似文献
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丙烯齐聚催化剂的反应性能 总被引:1,自引:0,他引:1
研究了丙烯在磷盐催化剂上催化齐聚过程,考察了反应温度、反应压力、接触时间及进料丙烯与氮气摩尔比对反应转化率和选择性的影响。结果表明,在合适的工艺条件下,丙烯转化率约76%,壬烯选择性约60%,十二烯选择性约30%。 相似文献
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甲醇乙烯烷基化反应体系热力学分析 总被引:2,自引:0,他引:2
考察了甲醇乙烯烷基化反应体系各独立反应吉布斯自由能随温度变化情况,采用吉布斯自由能最小法计算得到不同反应条件下体系平衡组成。结果表明:该反应体系主要受动力学控制;适当升高温度有利于烯烃生成,且乙烯和丁烯的生成是丙烯生成反应的阻碍点;在只生成丙烯的极端情况下,单独考察生成丙烯的反应,为了提高丙烯产率,需要适当降低反应温度,若综合考虑设备和能耗等因素,体系存在最佳反应压力和进料比(乙烯与甲醇摩尔比)。 相似文献
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考察了碱处理-水处理组合改性ZSM-5分子筛催化剂上,原料比例对丁烷与甲醇共进料芳构化反应性能的影响,结果表明:与丁烷相比,甲醇及其转化生成的烯烃中间体在分子筛上发生更强烈的吸附,导致丁烷分子被活化的比例降低,其转化率随原料中甲醇含量升高呈线性下降,甲醇的加入显著抑制了产物中甲烷、乙烷等副产物的生成;在所考察反应条件下纯丁烷进料时,丁烷活化生成的低碳烯烃中间体以丙烯为主,且其浓度相对较低不利于其通过多步骤反应生成芳烃,而主要通过氢转移生成丙烷;随原料中甲醇含量升高,反应体系中低碳烯烃中间体浓度增加,促进了其通过聚合、环化脱氢/氢转移等过程生成芳烃,芳烃选择性上升,丙烷生成量相对下降;其共进料芳构化的产物芳烃以多甲基取代芳烃为主,呈现出明显的多甲基化特征,C10以上芳烃较少;除了反应过程热量耦合外,与理论芳烃选择性相比,不同比例丁烷和甲醇共进料还有效提高了目的产物芳烃的选择性,显著出较好的工业应用前景。 相似文献
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采用浸渍法制备Pd-Ag/α-Al2O3催化剂,采用碳二前脱丙烷前加氢工艺系统考察反应器入口温度、空速和反应压力对催化剂性能的影响。结果表明,随着反应器入口温度升高,乙炔和丙炔+丙二烯转化率提高,乙烯选择性提高至一定值后趋于稳定,丙烯选择性波动不大,正丁烯生成量增加,较为适宜的反应器入口温度为(60~70)℃;随着空速升高,乙炔和丙炔+丙二烯转化率降低,乙烯选择性提高,丙烯选择性变化不大,正丁烯生成量降低,较为适宜的空速为(12 000~14 000)h-1;随着反应压力升高,乙炔转化率和丙炔+丙二烯转化率略增,乙烯选择性降低,较为适宜的反应压力为3.6 MPa。 相似文献
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《Catalysis communications》2009,10(15):2515-2519
Co-reaction of ethene and methanol was carried out over HZSM-5, P-La modified ZSM-5 (PLaHZ) and hydrothermal-treated PLaHZ catalysts. Hydrothermal treatment at high temperature sharply reduced the acidity of the catalyst, on which the direct conversion of ethene or methanol/dimethyl ether was almost completely suppressed. Co-feeding of ethene and methanol over the said catalyst resulted in considerable conversion of both reactants. Meanwhile, high propene selectivity (ca. 80%) was obtained at lower conversions. The methylation of ethene by methanol was responsible for the enhancement of conversions and propene selectivity in the co-reaction system. The further methylation of propene and the cracking of higher olefins were also operative under current reaction conditions. 相似文献
13.
M. Kangas J. Villegas N. Kumar T. Salmi D.Yu. Murzin F. Sandelin E. Harlin 《Catalysis Today》2005,100(3-4):363-366
An investigation of the effect of reaction conditions on product distribution in the skeletal isomerisation reaction of linear butenes has been carried out. The main reaction routes over ferrierite have been identified. Beside the main product isobutene, major by-product formation occurs. The unwanted reactions include dimerisation of butene to form octenes, hydrogen transfer yielding small amounts of saturated C3 and C4 hydrocarbons and disproportionation producing propene and pentenes. The most abundant by-products were pentene and propene, though these were not formed in equimolar amounts as could be expected. Oligomerisation experiments of propene over ferrierite produced large amounts of butene and pentene, revealing the presence of adsorbed nonene. The cracking of this surface species to hexene and propene is the most likely reaction route for the excess propene formation. This additional path to propene formation operates mainly at temperatures above 623 K. 相似文献
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The direct catalytic dehydrogenation of propane to propene is an important route to enhance propene production. In the present
experimentation the focus was to investigate the influence of incipient operating conditions, Si/Al ratio of zeolite support
and effect of zinc doping on Pt-Sn/ZSM-5 catalyst performance. The catalysts were extensively investigated by reaction tests
in a continuous plug-flow quartz micro-reactor. The experimental data shows that the manipulation of operating parameters
significantly improves the reaction performance, while huge dynamicity is observed in product distribution. Reaction temperature,
600 °C is found to be most suitable, while increasing the weight hourly space velocity (WHSV), propene selectivity improves
at the expense of lower conversion. The OPE was drawn to observe overall reaction network. It was found that the acidity of
zeolitic support plays a more important role in achieving desired product selectivity than additional metallic content. Accordingly,
the Si/Al ratio of the ZSM-5 zeolite the pro- pene selectivity was enhanced, leading to remarkable improvement in the total
olefins selectivity which was remarkably improved owing to a suppression of secondary reactions. At Si/Al ratio 300, the selectivity
of propene and total olefins becomes stable at 73% and 90% respectively. The doping of Zn on Pt-Sn/ZSM-5 improves only propene
selectivity, but is severely affected by quick deactivation. 相似文献
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Catalytic cracking of butene over potassium modified ZSM-5 catalysts was carried out in a fixed-bed microreactor. By increasing the K loading on the ZSM-5, butene conversion and ethene selectivity decreased almost linearly, while propene selectivity increased first, then passed through a maximum (about 50% selectivity) with the addition of ca. 0.7–1.0% K, and then decreased slowly with further increasing of the K loading. The reaction conditions were 620 °C, WHSV 3.5 h−1, 0.1 MPa 1-butene partial pressure and 1 h of time on stream. Both by potassium modification of the ZSM-5 zeolite and by N2 addition in the butene feed could enhance the selectivity towards propene effectively, but the catalyst stability did not show any improvement. On the other hand, addition of water to the butene feed could not only increase the butene conversion, but also improve the stability of the 0.7%K/ZSM-5 catalyst due to the effective removal of the coke formed, as demonstrated by the TPO spectra. XRD results indicated that the ZSM-5 structure of the 0.07% K/ZSM-5 catalyst was not destroyed even under this serious condition of adding water at 620 °C. 相似文献
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Haibo Jin Heng Jiang Suohe Yang Guangxiang He Xiaoyan Guo 《Chemical Engineering Communications》2019,206(3):346-354
The dimerization of propene to 4-methyl-1-pentene (4MP1) was studied in a fixed-bed reactor at 150?°C temperature, 8?MPa pressure, and 1?h?1 liquid hourly space velocity (LHSV) in the presence of solid superbase with 20?wt% one-pass conversion to hexene and 88% selectivity toward 4MP1. Based on the reaction results, propene competes with 4MP1 for adsorption on the catalyst surface. A higher reaction pressure or a lower liquid rate of 4MP1, controlled by a suitable propene LHSV or reaction temperature, was beneficial to the adsorption of propene, which reduced the isomerization of 4MP1. Under optimized conditions, propene dimerization was stable for 200?h, and isomerization was limited to less than 5%, yielding products with about 19% one-pass conversion to hexene by weight and 87% selectivity toward 4MP1. 相似文献
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Angela Dibenedetto Michele Aresta Francesco Nocito Carlo Pastore Anna M. Venezia Ekaterina Chirykalova Vladimir I. Kononenko Vladimir G. Shevchenko Irina A. Chupova 《Catalysis Today》2006,115(1-4):117-123
Reticular oxygen of Al2O3 or CeOx supported on Al2O3 was used for the epoxidation of propene without any double bond cleavage. In batch reaction, Al2O3 alone was able to convert propene into propene oxide (PO) with 100% selectivity and 2% conversion of propene with a close to 3:1 ratio with respect to the number of Al(III) reduced to elemental Al. When Ce2O3/Al2O3 or CeO2/Al2O3 was used, Al remained in its +3 oxidation state, while the Ce oxide was the oxidant as demonstrated by XPS analyses. CeOx/Al2O3 was more active (propene conversion yield of 4–5%) but the selectivity was lower (70%) as PO was isomerized into acetone and propionaldehyde.
Interestingly the use of reticular oxygen very much improves the selectivity with respect to the use of pure O2. In fact, while propene was more efficiently oxidized (10%) with O2 in presence of Al2O3 or CeOx/Al2O3, the selectivity was as low as 40% because C1 and C2 products were formed. However, the use of reticular oxygen represents a selective two-step technique for the use of molecular oxygen as oxidant of propene. The used oxides can be re-oxidized and the whole process can be further improved towards higher yields.
PO is quantitatively converted into propene carbonate by reaction with CO2 in presence of Nb2O5. 相似文献