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HZSM-5型分子筛催化合成2-乙酰噻吩 总被引:1,自引:0,他引:1
用固体酸催化剂HZSM-5型分子筛代替液体磷酸催化合成2-乙酰噻吩,探讨了反应时间、反应温度、催化剂质量对该反应的影响。采用正交实验法优化的工艺条件是:反应温度为95℃,反应时间为2.5 h,催化剂质量为2.5 g(约占原料质量的3.5%)。最优工艺条件下2-乙酰噻吩的收率为90.60%。产物通过色谱-质谱联用仪分析可知:产品2-乙酰噻吩的质量分数约为98.28%,副产物主要是少量的3-乙酰噻吩。该实验中,固体催化剂可以回收、再生和重复使用,给出的收率几乎与新鲜的催化剂相同。 相似文献
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固体酸催化剂合成2-乙酰噻吩 总被引:1,自引:0,他引:1
针对传统的合成2-乙酰噻吩的方法存在的一些弊端,选用环境友好型催化剂-磷钨酸来合成2-乙酰噻吩.磷钨酸除了具备一般质子酸的特点外,还具备一系列的优点:成本低、分解温度高、合成简便等.通过实验,考察了反应温度、反应时间和催化剂用量对该反应的影响,确定该反应的最适宜反应条件为:反应温度为85 ℃,反应时间为2.5 h,催化剂用量为0.5 g,产品的转化率约90%.产物通过色-质联用仪分析可知:产品2-乙酰噻吩质量分数约97.99%,副产物主要是少量的3-乙酰噻吩.由此也证明了磷钨酸作为本反应的催化剂,有着较高的选择性.这种方法同以往的方法相比较,更具备无设备腐蚀、减少环境污染等优势,产品同催化剂易于分离. 相似文献
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在滴流床反应器中,以C25沸石分子筛为催化剂,噻吩和乙酸酐为原料对噻吩酰化合成2-乙酰噻吩进行了连续反应实验研究。通过正交试验研究了反应温度、原料配比、进料流量对噻吩Friedel-Crafts酰基化反应的影响,确定了最佳反应条件:反应温度70℃,噻吩与乙酸酐摩尔配比1∶2,进料流量0.05mL/min。考察了副产物乙酸对反应的影响,确定了噻吩、乙酸酐和乙酸的最佳摩尔比为1∶2∶1,在最佳反应条件下,单位质量催化剂的2-乙酰噻吩产量为15.10g,催化剂寿命是4215min,噻吩初始转化率高达99.98%。采用固体13C、27Al核磁共振技术、热重分析对催化剂进行表征,结果表明,催化剂主要催化活性在B酸位,失活类型为高沸点物质的积炭失活。 相似文献
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采用二氧化硅负载固体磷钨酸盐催化剂,以乙酸酐和噻吩为原料合成2-乙酰噻吩。通过实验考察了固体酸盐催化剂用量、反应时间、反应温度、催化剂重复使用次数对2-乙酰噻吩合成转化率的影响。确定该反应的最适条件为:反应温度85℃,反应时间4h,催化剂用量(质量分数)3.0%-3.5%,催化剂重复使用3次。产品的转化率为80%以上,最高转化率达到90.75%。产品通过气相色谱分析,2.乙酰噻吩质量分数达99.5%以上,副产物主要为3-乙酰噻吩。由此证明,磷钨酸盐作为本反应的催化剂,有着较高的选择性。该方法同以往的方法相比较,具有无设备腐蚀、减少环境污染等优势。产品同催化剂易分离,且催化剂可重复利用。 相似文献
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在脱水剂PCl3的存在下,噻吩-2,5-二甲酸与乙醇胺反应直接生成噻吩-2,5-双噁唑啉及未环化产物1和2。副产物1和2碱性关环生成噻吩-2,5-双噁唑啉,总收率达63%。此方法的优点是合成路线短,操作简单。 相似文献
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Energy transfer in the photoluminescence of poly(3-thiophene acetic acid)-poly(vinyl alcohol) blends
We have investigated the optical properties of polymeric blend poly(3-thiophene acetic acid)-poly(vinyl alcohol). We have observed two band sets with different features in the photoluminescence spectrum. One set shows a band peak at 560 nm and the other shows two band peaks at 670 and 710 nm. We have analyzed the polarization and temperature dependence of photoluminescence spectrum. We have observed that the first set is unpolarized and shows weak temperature dependence, while the second one shows strong temperature dependence and a polarized band at 710 nm. These results were interpreted as evidence of energy transfer associated with migration and trapping of excitons in the poly(3-thiophene acetic acid) chains using a kinetic model with we estimated the energy of the trap site for the triplet exciton emissions. 相似文献
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This paper studies the detection of copper ions by using an iminodiacetatic acid (IDA) modified conducting copolymer electrode. The copolymer film comprising 3-methyl thiophene (3MT) and 3-thiophene acetic acid (3TA) was chosen as the selective metal cation sensing electrode. The carboxylic group of the copolymer was modified to produce IDA group for metal ion capture. The modified electrode was used for the electrochemical analysis of trace copper ions by square wave voltammetry (SWV) technique. The electrode was found to be highly selective to Cu2+ in the range of 0.1-10 μM. The modified electrode offered an excellent way, with a high stability and reusability, for selective determination of Cu2+ in a solution of mixed metal ions. 相似文献
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以噻吩为起始物料,氢溴酸经氧化剂氧化、溴化、格式反应制得格式试剂,格式试剂与环氧乙烷反应,水解得到2-噻吩乙醇,总收率可达72%以上。与溴素溴化相比该改进更适合工业化生产,环境更友好。 相似文献
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以3-氨基-2-噻吩甲酸甲酯为原料,经氯磺化、甲胺化、N-烷基化、环合等反应合成了替诺昔康的中间体4-羟基-3-甲基-2H-噻吩并[2,3-e]-1,2-噻嗪-2-羧酸甲酯-1,1-二氧化物(MHTTCD)。氯磺化时在大大减少溶剂(醋酸)用量的条件下,收率为78%,甲胺化收率为81.6%。环合反应在甲醇钠的甲醇溶液中进行,合适的甲醇钠浓度为1mol/L。回流反应1h,该步收率达55.5%。合成路线反应总收率为11.11%。通过GC-MS确认了各中间体的结构。由于N-烷基化时以氯乙酸乙酯代替肌氨酸乙酯盐酸盐以及收率的提高,降低了合成成本。 相似文献
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E. Toukoniitty P. Mäki-Arvela N. Kumar T. Salmi D. Yu. Murzin 《Catalysis Letters》2004,95(3-4):179-183
Depending on the reaction medium (toluene or acetic acid) striking differences were observed in the development of enantiomeric excess with time-on-stream in continuous enantioselective hydrogenation of ethylbenzoylformate on cinchonidine-modified Pt/Al2O3, which correlated well with the amount of adsorbed cinchonidine on alumina and silica from acetic acid and toluene solutions. Maximally 93% enantiometric excess (ee) of (R)-ethyl mandelate was obtained. 相似文献
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固体超强酸S2O2-8/TiO2的溶胶-凝胶法制备与表征 总被引:1,自引:0,他引:1
以钛酸四丁酯、无水乙醇、冰醋酸和过硫酸铵等为原料,采用溶胶-凝胶法制得前驱体,再经500 ℃焙烧得到固体超强酸S2O2-8/TiO2催化剂,采用XRD、IR和Hammett指示剂法对其进行表征,结果显示催化剂样品为超强酸,酸强度H0<-14.52。以乙酸乙酯合成反应为模型反应考察其催化活性和稳定性。结果表明,催化剂有较高的活性,当反应条件为醇酸体积比1.5∶1、催化剂0.6 g和反应时间3.0 h时,乙酸转化率可达73.09%(不加分水器)。催化剂稳定性较好,活性下降缓慢,可在无需任何再生的条件下重复使用。重复使用5次后,乙酸转化率仍然达55.13%。 相似文献
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M. Ai 《Catalysis Today》1992,13(4):679-684
Partial oxidation of propane was performed over V2O5-P2O5-based catalysts in the presence of a large excess of oxygen at 350 to 400°C. The main products were acrylic acid, acetic acid, and carbon oxides. Of the V2O5- P2O5 binary oxides, the best catalyst performances were obtained at a P/V atomic ratio of 1.00; the presence of an excess of phosphorus with respect to the P/V = 1.00 composition induced a large decrease in both the activity and selectivity to form acids. Incorporation of H3PMo12O40 to a P/V = 1.00 oxide enhanced greatly the formation of acetic acid. 相似文献
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Experimental data on density and viscosity at 303.15K and 323.15K are presented for the binary mixtures of p-xylene with cyclohexane, n-heptane, n-octane, sulfolane, N-methyl-2-pyrrolidone and acetic acid. From these data, the excess molar volume and deviations in viscosity have been calculated. The computed quantities have been fitted to the Redlich-Kister Equation to derive coefficients and estimate the standard error values. Results are discussed in terms of intermolecular interactions. 相似文献