纳米固体超酸SO42-/TiO2的研究

The new nanosolid superacid catalyst SO₄^2-/TiO₂ is compounded with nanometer chemical technology. This catalyst SO₄^2-/TiO₂ has good catalytic effects on esterificational reactions of ethylic acid and ethyl alcohol. It has many other advantages such as strong water-proof quality, being able to be used repeatedly, being easy to be re-claimed, non-corroding, non-polluting. So it is a green industrial catalyst which is helpful to the environment and possesses wide prospect of applications. The crystallo-process, specific surface area and sulphur content of the SO₄^2-/TiO₂ system have been studied with the method of XRD, XPS and the chemical analysis, the result of which indicates that catalytic activity and acid strength of SO₄^2-/TiO₂ is affected by the H₂SO₄ saturant concentration, baking temperature, precipitating condition, specific surface area and sulphur content. The best preparation conditions of SO₄^2-/TiO₂ are: ageing temperature at 0℃, 0.5mol·L^-1 of H₂SO₄ concentration, baking temperature at 500℃and 3 hours of baking time.     

大孔SO42-/ZrO2-SiO2复合固体酸制备及催化性能

利用浸渍水解法在大孔SiO2载体上组装固体酸制备出大孔径SO42-/ZrO2-SiO2复合固体酸催化剂。用扫描电镜、红外光谱仪和粉末X射线衍射仪等对其进行表征,结果表明:大孔SiO2载体的毛细管效应促使ZrO2以纳米薄层方式均匀地沉积在SiO2薄层表面,并抑制了ZrO2晶体的生长和晶相的转变,载体的大孔全连通的结构赋予该复合材料高的通透性(孔径在1~2μm)、两面活性点和大的比表面积(约156 m2.g-1)。Hammett指示剂法测得经550℃焙烧后产物的酸强度H0值小于-13.75,属于固体超强酸。以乙酸正丁酯的合成为探针反应考察硫酸浸渍液浓度、焙烧温度等制备条件对其催化活性的影响,结果表明,该SO42-/ZrO2-SiO2固体酸具有较好的催化活性,当焙烧温度为550℃和硫酸浸渍液浓度为1.5 mol.L-1时,超强酸对酯化反应的催化酯化率达到97%。     

SO42-/ZrO2的制备工艺对催化橡胶籽油裂解油酯化的影响

以SO₄^2-/ZrO₂为催化剂对橡胶籽油裂解油进行甲酯化。研究了锆源、焙烧温度及焙烧时间对催化剂活性的影响,分别采用氨气吸附程序升温脱附(NH₃-TPD)和吡啶红外(Py-IR)对固体酸SO₄^2-/ZrO₂的酸性和酸型进行分析。实验结果表明,以ZrOCl₂为锆源,550℃焙烧4 h所得固体酸SO₄^2-/ZrO₂的催化活性最好,性能较稳定。对酯化产物的组成及性能进行了考察,结果表明,酯化产物的各项性能均优于传统工艺制备的生物燃油,且与0^#柴油相近。     

抗水性固体酸SO42--TiO2-Clay催化剂的制备及应用

固体酸催化剂以其对设备无腐蚀,后处理工艺简单,选择性好和催化剂易回收等优势逐步替代液体酸,日益受到人们的重视,特别是抗水性固体酸催化剂[1~3],因其有高活性和可回收循环使用的特点,受到了广泛的关注。     

稀土改性对SO42-/ZrO2固体酸催化剂结构与催化性能的影响

采用共沉淀法和浸渍法在不同条件下制备了稀土-SO₄^2-/ZrO₂系列固体酸催化剂。使用废油脂与甲醇的酯交换反应评价了催化剂活性,并通过X射线衍射、红外光谱、比表面积测定表征方法考察了催化剂结构和性能的关系。结果表明,La摩尔掺杂量4%、焙烧温度600℃时制得的SO₄^2-/ZrO₂-La₂O₃催化剂活性最高,此时脂肪酸甲酯的产率为64.68%,且具有较好的重复使用性。稀土的引入使活性四方相ZrO₂更加稳定,600℃焙烧使催化剂既具有较多活性四方相ZrO₂,又具有较大比表面积,从而提高了催化剂活性。催化剂中形成了固体超强酸结构,且改性后酸强度增大,催化剂活性中心数目增加。     

磁性固体超强酸SO42-/ZrO2-Al2O3-Fe3O4的制备与性能研究

利用化学共沉淀法将磁性基质与固体酸组装制备磁性纳米固体超强酸催化剂,利用XRD、Raman、TG-DSC、M?ssbauer、TEM、HRTEM等手段对样品性质进行表征。结果表明：磁性基质的引入赋予固体超强酸以超顺磁性;Fe₃O₄、Al₂O₃粒子弥散在ZrO₂基质中,烧结过程中阻碍了扩散传质的进行以及晶界移动,抑制了ZrO₂晶体生长,稳定了四方晶相(T-ZrO₂);样品粒径分布集中,平均约为32 nm;HRTEM显示T-ZrO₂晶体生长取向于(101)方向,晶面间距d(101)=0.29 nm;Hammett指示剂法测得经600 ℃焙烧后产物的酸强度H_o＜-13.8,酸强度大于浓硫酸(H_o=-11.93)。以柠檬酸三丁酯的合成作为磁性固体超强酸SO₄^2-/ZrO₂-Al₂O₃-Fe₃O₄催化剂的探针反应,结果表明外磁场的引入提高了柠檬酸的转化率。     

硬脂酸法制备SO42-/Fe2O3-SiO2固体酸及其催化性能的初步探讨

首次用硬脂酸法制备了Fe2O3-SiO2混合氧化物,经浸渍H2SO4后再焙烧得SO2-4/Fe2O3-SiO2固体酸催化剂.用TEM,XRD,N2吸附/脱附和TG-DTA等手段对其进行了表征,结果显示制得的Fe2O3-SiO2混合氧化物具有多孔结构.且随着Si含量的增大,其比表面积明显增大,但孔径减小.用乙酸/丁醇酯化催化反应评估了该固体酸的催化性能.     

固体超强酸SO42-/SnO2-TiO2-Al2O3催化合成PEG6000双山嵛酸酯

以自制的固体超强酸SO42-/SnO2-TiO2-Al2O3催化山嵛酸与聚乙二醇6000(PEG6000)的酯化反应,合成了PEG6000双山嵛酸酯(DB6000),其结构经IR确证。较适宜的反应条件为:PEG6000 80 mmol,n(山嵛酸):n(PEG6000)=2.2:1.0,催化剂用量为总反应物质量的0.8%,氮气保护下于210℃反应6 h,酯化率高于99%。     

高岭土负载SO42-/ZrO2-TiO2催化剂的制备及其在缩酮合成中的应用

以经H2SO4处理焙烧的高岭土为载体,制备了以其负载的SO2-4/ZrO2-TiO2固体酸催化剂。 用FT-IR、XRD和NH3-TPD等测试技术表征了催化剂的微观结构及酸强度,考察了对环己酮乙二醇缩酮反应的催化活性及稳定性。 结果表明,酸化处理使高岭土表面酸量增加,但酸强度变化不大,而其负载SO2-4/ZrO2-TiO2后,经500 ℃焙烧3 h其酸量及酸强度显著升高。 环己酮用量为0.2 mol、乙二醇0.24 mol、催化剂1.2 g、带水剂环己烷15 mL,回流反应70 min后,缩酮收率可达96.8%,催化剂重复使用5次收率保持在90%以上。     

新工艺制备固体超强酸SO42-/SnO2-Nb2O5及其催化松油醇酯化

采用新工艺制备固体超强酸SO42-/SnO2-Nb2O5,将其应用于松油酯化反应。催化剂最佳制备条件:Nb2O5引入(SnO2质量分数)3%,浸渍硫酸浓度1.5 mol/L,500℃焙烧3.0 h;最佳反应条件:n(松油醇):n(乙酸酐)=1.0:1.2,催化剂用量(松油醇质量分数)5%,50℃反应3.0 h;并采用FT-IR、XRD、TG-DTA对催化剂进行表征。结果表明:催化剂可使得松油醇转化率达94.3%,乙酸松油酯选择性达86.2%,新工艺制备的催化剂较沉淀法和sol-gel法的活性高。     

麻疯树叶二氧化碳超临界萃取物的化学成分分析

采用二氧化碳超临界萃取技术(Supercritical Fluid Extraction)及常用的溶剂提取法(Solvent Draw)研究麻疯树叶提取物的化学成分，用气-质联用(GC／MS)方法对分离的化合物进行结构鉴定，应用色谱峰面积归一化法测定各成分的相对百分含量，并对其进行分析。两种提取法结果显示：二氧化碳超临界萃取法具有对有效成分提取完全、效率高、耗时少等优点。     

The Performance of Jatropha Curcas Linn. Capsule Husk as Feedstocks Biogas in One Phase Anaerobic Digestion

Jatropa curcas Linn. (JcL) capsule husk was not recommended as biogas feedstocks. However for biorefinery purpose, several technologies have been conducting to solve this problem. This research reported quantity and quality comparison of Dry Husk Jcl (DH-JcL) in one phase system of batch digester compare with semi continuous digester. HDPE drum of 80 L working volume used as digester with 40 days hydraulic retention time. Feeding of DH-Jcl and solvent water was mixed on concentration of 1: 8. Research conclusion showed that semi continuous digester was better than batch digester. Biogas quality showed that methane content can reach 66.61% to 83.15% and biogas quantity in semi continuous digester can reach 0.016 m³ · kg^–1 DH JcL. The result was not in optimize condition yet because ratio number of volatile fatty acids/ alkalinity showed 0.5, it was indicated unstable anaerobic degradation process of DH-JcL.     

Diazomethane Esterification of Fatty Acids by Reaction-Gas Chromatography

Abstract

An exploratory study was made of the esterification of octanoic acid using reaction-gas chromatography and diazo-methane prepared by distillation as reagent. The technique does not require esterification external to the chromatographic system.     

固体酸ZrO2-Ce2O3／SO4^2-催化合成丙二酸二丁酯

以含铈固体超强酸ZrO2-Ce2O3／SO4^2-为催化剂，丙二酸和正丁醇为原料合成了丙二酸二丁酯。最佳反应条件为：催化剂活化温度500℃，丙二酸100mmol，n(酸)：n(醇)=1．0：2．5，催化剂用量1g,反应时间2h，酯化率达95．8％。结果表明，加入铈有助于提高固体超强酸的使用寿命。     

Esterification of sorbitol and lauric acid with catalystp-TSA

Kinetics of the esterification of sorbitol with lauric acid in the presence ofp-TSA as a catalyst has been studied. A kinetic model of reversible second order reaction was proposed for the esterification. Parameters in the model (kinetic constants) were estimated by non-linear regression. The temperature dependence of the rate was calculated from the experimental constants estimated at various temperatures, using the Arrhenius equation. Experimental results are in good accordance with the proposed theoretical model.     

The kinetics of transformation of isopentenols in the presence of the Nafion-H catalyst

The kinetics of transformation of 3-methyl-1-buten-3-ol in the presence of the Nafion-H catalyst was studied. A comparison between the data obtained and those for the reaction catalyzed by sulfuric acid showed that under the same conditions, the macroscopic acidic properties of Nafion-H correspond to the catalytic activity of 8–15% sulfuric acid. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 10, pp. 2090–2093, October, 1998.     

脂肪酸在超临界甲醇中的酯化反应研究

超临界甲醇中的酯化和酯交换反应是利用植物油、动物油或废油脂制备生物柴油的新工艺.它的最大特点是不需要添加催化剂,超临界甲醇既是反应媒介,又是反应物.