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1.
以硅酸钠为原料,通过简单焙烧工艺制备固体碱催化剂,催化麻疯树子油制备生物柴油。考察了焙烧方法、焙烧温度和焙烧时间等制备条件对固体酸催化剂性能的影响,同时考察了反应温度、反应时间、催化剂用量和醇油比对酯交换反应结果的影响。实验结果表明:采用直接焙烧法,在400℃焙烧2 h催化剂具有较高的活性;催化剂的最佳反应条件为反应温度为90℃,反应时间为50 min,催化剂用量为3%,醇油物质的量比为11:1,其酯交换率为99.9%。  相似文献   

2.
采用简单的浸渍法制备了负载型镁铝复合氧化物催化剂,并考察了催化剂在碳酸二甲酯与碳酸二乙酯酯交换反应上的催化性能。系统地研究了载体种类、Mg/Al比、焙烧温度对材料催化性能的影响。研究表明:采用炭材料NC-2为载体的催化剂活性最好,反应过程中无活性组分流失,反应后的催化剂经简单焙烧处理后可多次循环利用。  相似文献   

3.
王培祥  沈卫华  陈小朋  方云进 《应用化工》2023,(12):3345-3348+3353
以Li为主要活性组分,采用沉淀法制备了LiAl催化剂,通过引入不同的金属元素(Mg、La、Ce和Y)对LiAl催化剂进行改性,同时对催化剂进行了XRD、TG-DTG、CO2-TPD和BET表征,考察LiAl摩尔比、焙烧温度对甲醇和碳酸丙烯酯(PC)酯交换合成碳酸二甲酯(DMC)反应活性的影响。结果表明,催化剂Li/Al摩尔比为3∶1,焙烧温度为500℃时,催化剂具有最高的反应活性。其中,LiYAl催化剂在反应条件为65℃,甲醇和PC的醇酯摩尔比为10∶1,催化剂用量为2%的条件下反应2 h, DMC的产率为59.2%,重复使用4次后,仍具有较高的产率。  相似文献   

4.
采用氨水为沉淀剂,共沉淀法制备了一系列MgCaAl复合酸碱氧化物催化剂.考察了催化剂的金属离子比、共沉淀时的溶液pH值、晶化温度、焙烧温度等条件对制备的催化剂在丙酮缩合制异佛尔酮反应中催化活性的影响.实验结果表明,所制备的复合固体催化剂在丙酮气相缩合制备异佛尔酮的反应中表现出良好的活性.在Mg/Ca/Al 物质的量比为...  相似文献   

5.
李川  万新军  任玉洁  周菁  陈洁  刘敏 《应用化工》2013,(10):1826-1828,1835
采用等体积浸渍法制备了NaOH/NaX固体碱催化剂,用于催化大豆油与甲醇酯交换反应制备甲酯生物柴油。考察了NaOH负载量、焙烧温度、反应时间、反应温度、催化剂用量和醇油摩尔比对转化率的影响。结果表明,在NaOH负载量25%,焙烧温度500℃,反应时间4 h,反应温度65℃,催化剂用量3%和醇油摩尔比12条件下,转化率达95.3%。  相似文献   

6.
固体碱催化黄连木籽油制备生物柴油   总被引:2,自引:1,他引:1  
制备了K2CO3/Mg(A l)O固体碱催化剂,适宜制备条件为:K2CO3负载量30%、在700℃下焙烧4 h。用比表面积测定仪、X射线衍射仪、红外光谱仪对其进行了表征。以黄连木籽油为原料,开展了酯交换法制备生物柴油的研究,考察了主要影响因素:醇油摩尔比、催化剂用量、反应时间和反应温度对酯交换反应的影响,得到的酯交换反应适宜条件为:以黄连木籽油0.01 mol计,醇油摩尔比12∶1、催化剂用量为黄连木籽油质量的4.0%、反应时间2.5 h、反应温度68℃。在该条件下生物柴油的收率可达99%以上。催化剂经4次循环使用,生物柴油收率仍可保持在96%以上。用FTIR1、HNMR对所制备的产品进行了表征,证明产品中含有饱和脂肪酸甲酯和不饱和脂肪酸甲酯。  相似文献   

7.
以Na2Si O3·9H2O为原料制备固体碱催化剂,大豆油和甲醇酯交换反应为模型,优化固体碱焙烧条件。再以最优条件制备的Na2Si O3·9H2O固体碱催化剂优化大豆油和甲醇酯交换工艺。结果表明:硅酸钠固体碱最佳制备条件为煅烧温度400℃、煅烧时间1 h。大豆油和甲醇酯交换反应优化工艺为:反应温度65℃、醇油摩尔比6∶1、反应时间2 h。  相似文献   

8.
在固体超强酸SO4^2-/Al2O3-SiO2存在下,研究了环己醇脱水制备环己烯的反应,考察了Al2O3与SiO2的物质的量比、催化剂焙烧温度、催化剂用量及其重复使用对反应产率的影响,并通过实验得到了最佳反应条件。  相似文献   

9.
采用浸渍法制备了KF/Al2O3固体碱催化剂,并将其应用于大豆油与甲醇酯交换制备生物柴油的反应。通过酯交换反应的转化率对催化剂制备工艺进行了优化,得出最佳制备条件:KF理论负载质量分数为Al2O3的45%,浸渍时间6 h,焙烧温度500 ℃,优化条件下制备的催化剂在大豆油与甲醇物质的量比为12∶1、催化剂用量为油质量的2%、反应时间3 h和反应温度(60~65) ℃条件下,酯交换转化率可达97.15%。  相似文献   

10.
采用共沉淀法制备了La-Mg-Al类水滑石,利用XRD进行了表征,考察了该催化剂的制备条件,并探究了催化大豆油酯交换反应的优化条件。实验结果表明,在金属物质的量比为1∶2∶1,焙烧温度为500℃,焙烧时间为3 h的条件下制得的催化剂活性较高,并在反应温度为65℃,反应时间为3 h,醇油物质的量比为9∶1,催化剂用量为大豆油质量的3%的优化条件下催化酯交换反应,生物柴油的收率达到90.9%。  相似文献   

11.
Hong-yan Zeng  Zhen Feng  Xin Deng  Yu-qin Li 《Fuel》2008,87(13-14):3071-3076
Mg–Al hydrotalcites with different Mg/Al molar ratios were prepared and characterized by powder X-ray diffraction (XRD), Fourier-transform infrared spectra (FTIR), thermogravimetric apparatus and differential thermal analysis (TGA-DTA) and scanning electron micrograph (SEM). It was confirmed by XRD that the materials had hydrotalcite structure. The hydrotalcite catalyst calcined at 773 K with Mg/Al molar ratio of 3.0 exhibited the highest catalytic activity in the transesterification. In addition, a study for optimizing the transesterification reaction conditions such as molar ratio of the methanol to oil, the reaction temperature, the reaction time, the stirring speed and the amount of catalyst, was performed. The optimized parameters, 6:1 methanol/oil molar ratio with 1.5% catalyst (w/w of oil) reacted under stirring speed 300 rpm at 65 °C for 4 h reaction, gave a maximum ester conversion of 90.5%. Moreover, the solid catalyst could be easily separated and possibly reused.  相似文献   

12.
陆敏  刘媛  李树白  文艺  刘承先 《化工进展》2013,32(5):1070-1073
采用共沉淀法,在500 ℃烘干焙烧制备了类水滑石催化剂,采用X射线衍射(XRD)、红外光谱(FT-IR)、BET分析对催化剂进行了表征。将类水滑石催化剂应用于碳酸二甲酯(DMC)与正丙醇酯交换合成碳酸二丙酯(DPC)。研究结果表明:镁铝摩尔比为2∶1,在500 ℃焙烧后,类水滑石对反应有较高的催化活性;当丙醇∶DMC =3∶1(摩尔比)、催化剂用量为反应物总质量的1%、反应温度为90 ℃、反应时间为5 h时,DPC的收率为46.87%。  相似文献   

13.
原位合成层状双氢氧化物处理含镍废水   总被引:3,自引:0,他引:3  
俞志敏  刘景丽  陈天虎  吴克  金杰  许田 《硅酸盐学报》2006,34(11):1420-1424
利用配制的含镍模拟废水,研究了金属离子在层状双氢氧化物(layer double hydroxide,LDH)结构中的嵌入作用和利用原位合成LDH方法处理含重金属废水的可行性.通过单因素实验和正交实验,研究了pH值、温度、Mg2 与Al3 的摩尔比值对镍去除率的影响.结果表明:影响镍离子去除效率的因素主要是Mg2 与Al3 的摩尔比、pH值及镍离子初始浓度,且主次关系为pH值>Ni2 初始浓度>Mg与Al摩尔比.当pH在8.5,Mg2 /Al3 比值为1~2时,镍离子去除率最高,Mg2 ,Al3 利用率也较高.同时沉淀出的固体样品经X射线衍射和红外图谱分析证实为LDH晶体结构,Ni2 取代了部分Mg2 嵌入到LDH的八面体层板中.  相似文献   

14.
A series of Mg–Zr catalysts with varying Mg to Zr ratios was prepared by co-precipitation method. These catalysts were characterized by BET surface area, X-ray diffraction, X-ray photo electron spectroscopy and temperature programmed desorption of CO2. The catalytic activity of these catalysts was evaluated for the room temperature transesterification of both edible and non-edible oils to their corresponding fatty acid methyl esters. The catalyst with Mg/Zr (2:1 wt./wt.%) exhibited exceptional activity towards transesterification reaction within short reaction time. The effects of different reaction parameters such as catalyst to oil mass ratio, reaction temperature, reaction time and methanol to oil molar ratio were studied to optimize the reaction conditions. The reasons for the observed activity of these catalysts are discussed in terms of their basicity and other physico-chemical properties.  相似文献   

15.
采用等体积浸渍法制备了不同Pd负载量和不同Pd与Zn物质的量比的PdZn/Al<,2>O<,3>甲醇水蒸汽重整颗粒催化剂,结果表明,Pd负载质量分数9.25%和n(Pd):n(Zn)=0.24的催化剂表现出较佳的催化性能.XRD表征表明,由于生成了较大的Pd-Zn合金粒子,从而有利于甲醇重整反应的进行.制备了金属壁载型...  相似文献   

16.
Ni/Mg–Al catalysts derived from hydrotalcite-type precursors were prepared by a co-precipitation technique and applied to steam reforming of methane. By comparison with Ni/γ-Al2O3 and Ni/α-Al2O3 catalysts prepared by in-cipient wetness impregnation, the Ni/Mg–Al catalyst presented much higher activity as a result of higher specific surface area and better Ni dispersion. The Ni/Mg–Al catalyst with a Ni/Mg/Al molar ratio of 0.5:2.5:1 exhibited the highest activity for steam methane reforming and was selected for kinetic investigation. With external and inter-nal diffusion limitations eliminated, kinetic experiments were carried out at atmospheric pressure and over a temperature range of 823–973 K. The results demonstrated that the overal conversion of CH4 and the conversion of CH4 to CO2 were strongly influenced by reaction temperature, residence time of reactants as wel as molar ratio of steam to methane. A classical Langmuir–Hinshelwood kinetic model proposed by Xu and Froment (1989) fitted the experimental data with excellent agreement. The estimated adsorption parameters were consistent thermodynamical y.  相似文献   

17.
甲醇溶析铝酸钠制备氢氧化铝   总被引:1,自引:0,他引:1  
以甲醇水溶液分解铝酸钠晶体,采用溶析法制备了超细氢氧化铝. 考察了30℃下氧化铝、氧化钠溶解度随甲醇质量分数的变化规律,研究了甲醇质量分数和反应温度对水合铝酸钠晶体分解工艺的影响,用XRD, IR, SEM及粒度分析、纯度分析等手段对制备的氢氧化铝产品进行了表征. 结果表明,随着溶剂中甲醇质量分数的增加,氧化铝和氧化钠溶解度均下降,但氧化铝下降幅度更大;铝酸钠溶液分子比(氧化钠/氧化铝摩尔比)先增加后减小,到甲醇质量分数为0.8左右时达到最大值. 30℃下水合铝酸钠晶体与甲醇质量分数为0.5~0.8的甲醇-水混合溶剂反应1~3 h,铝酸钠分解率可达到80%~90%,温度升高,分解率略有下降. 甲醇溶析得到的氢氧化铝30℃下为拜耳石型,温度升高逐渐变为三水铝石型,红外光谱完整. 产品形貌规则,为高纯薄片状超细氢氧化铝,平均厚度100 nm,平均粒径1.05 mm.  相似文献   

18.
Esters of fatty acids, derived from vegetable oils or animal fats, and known as biodiesel, are a promising alternative diesel fuel regarding the limited resources of fossil fuels and the environmental concerns. In this work, methanolysis of soybean oil was investigated using Mg-Al hydrotalcites as heterogeneous catalyst, evaluating the effect of Mg/Al ratio on the basicity and catalytic activity for biodiesel production. The catalysts were prepared with Al/(Mg + Al) molar ratios of 0.20, 0.25 and 0.33, and characterized by X-ray diffraction (XRD), textural analysis (BET method) and temperature-programmed desorption of CO2 (CO2-TPD). When the reaction was carried out at 230 °C with a methanol:soybean oil molar ratio of 13:1, a reaction time of 1 h and a catalyst loading of 5 wt.%, the oil conversion was 90% for the sample with Al/(Mg + Al) ratio of 0.33. This sample was the only one to show basic sites of medium strength. We also investigated the reuse of this catalyst, the effect of calcination temperature and made a comparison between refined and acidic oil.  相似文献   

19.
赵瑛祁  丁洪生  张于 《工业催化》2012,20(12):71-74
用Cp2ZrCl2/三异丁基铝/B(C6F5)3催化体系对1-辛烯的聚合进行研究,考察催化剂用量、反应温度、反应时间、Al与Zr物质的量比和B与Zr物质的量比等工艺条件的影响。确定1-辛烯齐聚的最佳工艺条件为:催化剂用量0.028 7 mmol,反应温度60 ℃,反应时间60 min,Al与Zr物质的量比为110,B与Zr物质的量比为1.5。  相似文献   

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