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乙酸选择性加氢制乙醇反应性能研究 《燃料化学学报》2016,44(7):862-869
在固定床反应器上考察了反应温度、反应压力、乙酸(HAC)液体进料空速、H_2/HAC(总气体空速GHSV或H_2流量)对乙酸选择性加氢制乙醇反应的影响,研究了乙酸转化率、产物选择性、乙醇时空收率的变化规律,验证了自主开发催化剂的稳定性。结果表明,副产物的选择性受反应条件的影响,选择合适的反应条件可以抑制乙酸乙酯和丙酮的生成。原料与催化剂床层接触时间小于5s时,可以避免发生乙酸加氢分解脱羰反应生成甲烷气相产物,也避免了乙醇的进一步反应生成乙烷。在反应温度为280℃,反应压力为2.5 MPa,乙酸进料液时空速为0.72 h~(-1),H_2/HAC(mol ratio)为16的条件下,乙酸乙酯选择性为6%。900 h长周期实验表明,自主开发催化剂具有较好的工业应用前景。 相似文献
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生物油模型化合物催化裂化制备芳香烃的实验研究 总被引:1,自引:0,他引:1
通过HZSM-5分子筛催化剂对生物油典型模型化合物(乙酸、愈创木酚、正庚烷和环己烷等)在550℃进行了催化裂化反应,研究模型化合物催化裂化特性和反应机理以及催化剂性质。结果表明,正庚烷和环己烷裂化产物主要是芳香烃(53%和91%,均为积分面积分数),对于此类不含氧的模型化合物,催化裂化反应过程更容易进行;随着催化剂用量的增加,可以有效增加乙酸裂化产物中芳香烃含量(12%到90%,均为积分面积分数);愈创木酚结构比较复杂,HZSM-5催化剂主要脱除了甲氧基,催化剂用量的增加可以使芳香烃类稳定物质更容易形成。 相似文献
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以α1-VOPO4相为催化剂, 在环己烷气相氧化脱氢反应中, 通过在原料中加入醋酸可控制反应产物的分布. 研究了不同醋酸量对目标产物选择性的影响, 醋酸在反应体系中优于环己烷吸附在α1-VOPO4催化剂的表面上, 使催化剂表面形成孤立的活性中心, 避免了产物环己烯的深度氧化. 反应温度为450 ℃, 醋酸与环己烷的摩尔比为12.9∶1时, 环己烷的转化率为6.9%, 环己烯的选择性为100%. 相似文献
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有关甲壳素的乙酰化已有报导[1-3],但报导的各种方法在产品性能等方面尚存在不少问题。本文报导在对甲苯磺酸或高氯酸-对甲苯磺酸催化下进行甲壳素乙酰化的新方法;同时,对用单一高氯酸催化的反应作了进一步研究,从而制得了高取代度及较高比浓粘度的乙酰化甲壳素产物。 相似文献
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以氯化铜、钼酸铵、苯酐、氯化铵、尿素和NaY分子筛为原料,采用苯酐-尿素法制备了酞菁铜/分子筛复合物CuPc/Y.采用等体积浸渍法将金属钯担载在CuPc/Y上制备了Pd-CuPc/Y催化剂,并在醋酸水溶液中考察了其催化甲烷选择氧化合成甲醇反应的性能,结果表明,催化性能与反应温度、溶剂中CH3COOH与H2O的混合比例、对苯醌用量、反应时间等因素有关,在0.5%Pd-0.5%CuPc/Y添加量0.5 g、CH3COOH与H2O体积比4∶1、对苯醌用量1 000 μmol、反应时间3 h、反应温度150 ℃的条件下,甲醇的最佳生成量为1 840 μmol.Pd-CuPc/Y催化剂可以多次循环使用,但由于催化剂流失和催化剂表面的钯粒子聚集的原因,循环使用后的催化剂催化活性有所下降.Pd-CuPc/Y在醋酸溶液中催化甲烷选择氧化合成甲醇是亲电取代反应和活性氧物种氧化共同作用的结果. 相似文献
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《Electrochemistry communications》2003,5(6):445-448
Peroxyacetic acid (PAA) has been first prepared from acetic acid in the presence of solid superacid, Nafion-H, as a catalyst at ambient temperature and atmospheric pressure using gas diffusion electrode (GDE) as an oxygen cathode. Hydrogen peroxide was electrogenerated by the reduction of oxygen on the GDE and PAA could be produced by a redox reaction between electrogenerated hydrogen peroxide and acetic acid. The continuous operation was carried out to examine the electrolysis performance of the present electrolysis system. The results demonstrate that the system can be continuously operated over one month with the production of PAA of ca. 1.9–2.3 mM. 相似文献
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Fabiane Hamerski Giovana Gonçalves Dusi Julia Trancoso Fernandes dos Santos Vítor Renan da Silva Fernando Augusto Pedersen Voll Marcos Lúcio Corazza 《国际化学动力学杂志》2020,52(8):499-512
This study reports experimental data and kinetic modeling of acetic acid esterification with n-pentanol using sulfated zirconia as a catalyst. Reactions were carried out in an isothermal well-mixed batch reactor at different temperatures (50-80°C), n-pentanol to acid molar ratios (1:1-3:1), and catalyst loadings (5-10 wt% in relation to the total amount of acetic acid). The reaction mechanism regarding the heterogeneous catalysis was evaluated considering pseudo-homogeneous, Eley–Rideal, and Langmuir–Hinshelwood model approaches. The reaction mixture was considered a nonideal solution and the UNIQUAC thermodynamic model was used to take into account the nonidealities in the liquid phase. The results obtained indicated that increases in the temperature and catalyst loading increased the product formation, while changes in the n-pentanol to acetic acid molar ratio showed no significant effect. The estimated enthalpy of the reaction was −8.49 kJ mol−1, suggesting a slightly exothermic reaction. The Eley–Rideal model, with acetic acid adsorbed on the catalyst as the limiting step, was found to be the most significant reaction mechanism. 相似文献
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VPO催化剂的再生性质及其对晶格氧选择氧化丙烷的影响 总被引:2,自引:0,他引:2
采用脉冲反应器,研究了VPO催化剂的再生性质及其对晶格氧选择氧化丙烷制丙烯酸和乙酸的影响,结果表明,VPO催化剂与气相分子氧反应的速度要比丙烷与其 和氧反应的速度慢许多,因此以丙烷-O2共进料方式进行反应时,催化剂氧化再生是速度控制步骤,水是影响催化剂选择性的重要因素,但对活性影响不大,在反应温度下,水在VPO催化剂 为可逆吸附,容易脱附流失,催化丙烷反应生成目的的产物的活性中心很稳定,主要是晶格 相似文献
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Madhu Sudan SahaYoshinori Nishiki Tsuneto FurutaAo Denggerile Takeo Ohsaka 《Tetrahedron letters》2003,44(29):5535-5537
A new method for the preparation of peroxyacetic acid from acetic acid and hydrogen peroxide in the presence of solid superacids as a catalyst under mild conditions has been proposed. The preparation of peroxyacetic acid could be carried out in a batchwise operation as well as in a flow-system operation. Nafion-H was found to be active and very stable catalyst for the preparation of peroxyacetic acid and to be regenerated without the loss of catalytic activity. 相似文献
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固体酸催化剂催化酯化反应研究:Ⅰ.催化剂的制备及性能 总被引:4,自引:0,他引:4
酯化反应是基本有机化学中的一个重要反应,传统上使用的浓H_2SO_4催化剂常常引起一些严重问题.如:设备腐蚀严重,引起副反应及产生大量难以处理的含酸残液等.近年来,采用各种分子筛,氧化物及超强酸等作为该过程的催化剂的研究工作多见报道,这些工作无疑具有重要意义,但主要问题在于低温催化活性不高. 相似文献
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N. I. Rudakova M. V. Klyuev Yu. G. Erykalov D. N. Ramazanov 《Russian Journal of General Chemistry》2006,76(9):1407-1409
Hydroxylation of benzene in acetic acid at 323 K was studied in the presence of a sodium orthovanadate catalyst. With hydrogen peroxide as aqueous solution, the yield of phenol was 12–14%. With hydrogen peroxide generated from dry sodium peroxide, the yield of phenol could be improved to 21–23%. The apparent decomposition rate constants of hydrogen peroxide in acetic acid are presented. 相似文献
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