杂多酸绿色催化合成蒽醌反应的研究

针对传统苯酐法合成蒽醌反应过程的严重环境污染问题,提出利用杂多酸绿色催化合成蒽醌的方法.以扩孔改性二氧化硅(SiO2)为载体,磷钨酸(HPW)为催化剂,制备负载型HPW/SiO2催化剂,系统考察其催化邻苯甲酰苯甲酸(BBA)合成蒽醌反应中不同性质溶剂的加入、溶剂用量、反应温度、反应时间、催化剂用量等对反应的影响,并对催...     

Cs-Sb_2O_5/SiO_2催化剂用于合成丙烯酸甲酯

以SiO2为载体,在其上负载碱金属Cs和Sb2O5作为活性组分制备出Cs-Sb2O5/SiO2型固体碱催化剂,经扫描电镜分析能谱分析(SEM/EDS)负载量Sb质量分数为10.06%,Cs质量分数为8.84%。使用该催化剂在固定床微反色谱装置上进行了催化醋酸甲酯一步法合成丙烯酸甲酯的工艺研究,通过色质联用仪确定其产物为丙烯酸甲酯。研究结果表明:当醋酸甲酯与甲醛的摩尔比为3∶1,空速在4—5h-1,反应温度在390℃时合成效果较好,丙烯酸甲酯的收率可达47.6%。     

负载型Cs2.5H0.5PW12O40醚化催化剂的制备与催化性能

制备了负载型磷钨酸铯 (Cs2 5H0 5PW1 2 O4 0 )催化剂 ,考察了载体种类、载体性质、制备方法和制备条件对催化剂性能的影响 ,对制备的催化剂进行了表征 ,并考察了负载型Cs2 5H0 5PW1 2 O4 0 作为醚化催化剂的催化活性 结果表明 ,大孔硅胶是Cs2 5H0 5PW1 2 O4 0 的适宜载体 ,硅胶的钠含量越低制备的Cs2 5H0 5PW1 2 O4 0 SiO2 催化剂的活性越高 .采用一步法和二步法制备的Cs2 5H0 5PW1 2 O4 0 SiO2 催化剂均具有较强的酸性、催化活性以及良好的稳定性 ,可以替代液体酸和阳离子交换树脂 ,成为一种环境友好的固体酸催化剂     

Cs2.5H0.5PW12O40/SiO2催化合成二甘醇二苯甲酸酯

以硅胶为载体，制备了固载磷钨酸酸式铯盐(Cs2．5H0．5PWl2O40／SiO2)催化剂，并用于催化合成二甘醇二苯甲酸蘸(DEDB)。研究了催化剂制备条件对催化性能的影响和反应条件对蘸化反应的影响。在n(酸)/n(醇)=2．2、催化剂用量为0．7％、反应温度80℃、反应时间4h、带水剂N2流量250mL的条件下，酯化率可达到99．67％。催化剂重复试验表明，该催化剂具有良好的活性与稳定性。     

介孔氧化铝钇负载磷钨酸催化剂制备及其催化性能

以尿素为沉淀剂,十二烷基硫酸钠为模板剂,采用均相沉淀法制备介孔氧化铝钇(Al_2O_3Y),并用浸渍法将磷钨酸(HPW)负载到Al_2O_3Y上。通过SEM、XRD、FT-IR和N_2吸附等手段对Al_2O_3Y及负载催化剂(Al_2O_3Y/HPW)进行表征。将普通Al_2O_3、介孔Al_2O_3Y和Al_2O_3Y/HPW分别催化合成十七烯基咪唑啉,结果表明,制备的介孔Al_2O_3Y为无定型,粒径(1～5)μm,平均孔径5.08 nm,最可几孔径2.25 nm,比表面积627.43 m~2·g~(-1)。磷钨酸的负载率为93.3%,热稳定性较好。在合成十七烯基咪唑啉的验证实验中,催化剂用量为反应物质量的1%,与普通Al_2O_3催化反应相比,合成反应时间缩短,反应温度降低,合成收率高出30%,可达98.2%。     

环己酮催化氧化合成ε-己内酯催化剂的研究——介孔分子筛超强酸催化剂的研制及表征

以离子液体作模板剂,十二胺为扩孔剂,采用水热晶化法合成出了大孔径的Al-MCM-41介孔分子筛,并采用浸渍法将SO2-4引入其骨架中,最终合成了SO2-4/Al-MCM-41超强酸介孔分子筛.通过XRD、TEM以及N2吸附-脱附等分析方法对其结构进行表征,并用Hammett指示剂法测得了样品的酸强度.结果表明:分子筛Al-MCM-41孔径可达7.1nm,结晶度保留率很低,负载SO2-4后酸度小于-11.99,达到了固体超强酸的要求.采用环己酮催化氧化合成ε-己内酯的反应对催化剂进行活性评价,结果表明,该催化剂有较高的活性.     

V205／Si02催化氧化乙二醛制备乙醛酸的研究

以SiO2为载体,采用等体积浸渍法合成V205／SiO2催化剂,用XRD对催化剂进行了表征,并考察了不同条件对催化氧化乙二醛制备乙醛酸的影响。结果表明,当负载量为1％、焙烧温度为550℃、反应温度为55℃、催化剂用量为0．20g时,催化效果最好,乙二醛的转化率可达12．02％,乙醛酸的得率为9．01％。     

负载型杂多酸PW12／SiO2催化合成乙酸乙酯

以SiO2为载体,采用饱和浸渍法制备负载型杂多酸PW12／SiO2,用于催化合成乙酸乙酯。通过正交试验确定最佳反应条件为:催化剂用量为反应物总质量的4％,酸醇摩尔比为3,反应回流时间为120 min,酯化率可达91.56％以上。     

硅胶负载磷钨酸铯盐(Cs2.5H0.5PW12O40)催化合成2-乙酰噻吩的研究

采用二步浸渍法制备硅胶负载磷钨酸铯(Cs2.5H0.5PW12O40)催化剂催化合成药物中间体2-乙酰噻吩.运用IR和XRD测试技术进了Cs2.5H0.5PW12O40/SiO2催化剂的表征,考察了Cs2.5H0.5PW12O40负载量、催化剂用量、物料配比、反应温度、反应时间等对2-乙酰噻吩合成收率和选择性的影响.实验结果表明,Cs2.5H0.5PW12O40和Cs2.5H0.5PW12O40/SiO2催化剂保持H3PW12O40的Keggin结构不变,且Cs2.5H0.5PW12O40/SiO2催化剂中Cs2.5H0.5PW12O40主要聚集在SiO2载体表面.优化合成2-乙酰噻吩的工艺条件为:30%Cs2.5H0.5PW12O40/SiO2催化剂用量为3%(以总物料量计);噻吩与乙酐的摩尔比为4:1;反应温度为75～80℃;反应时间为90 min.在此所选择的条件下,2-乙酰噻吩的收率达94.6%～96.8%,选择性达99.8%～99.9%.     

中孑L分布活性炭的制备与表征

以酚醛树脂为前驱体,纳米SiO2为模板剂,采用模板炭化和钾碱活化工艺研制中孔率较高、比表面积较大的中孔炭（Mesoporous carbon,MC）,考察了活化温度、活化时间、树脂模板比等工艺参数对活性炭孔结构的影响。测试了活性炭N2的吸附等温线、孔径分布、比表面积,并通过扫描电子显微镜观察其微观结构。结果表明,较优工艺条件为：树脂模板比为2：1、活化温度850℃、活化时间3h,该条件下所得中孔炭中孔率达91．4％,比表面积为1501m^2·g^-1,总孔孔容1．38m^2·g^-1,为理想的窄孔径分布活性炭。     

Novel methods to fabricate macroporous 3D carbon scaffolds and ordered surface mesopores on carbon filaments

New methods for fabrication of 3D macroporous carbon scaffolds and synthesis of mesopores on carbon surfaces are proposed. Ordered macroporous filamentary carbon structures were made by rapid prototyping using solvent-based extrusion freeforming which allows the scaffold to be designed on computer and downloaded directly to a building platform. The surface of extruded filaments was decorated with 20?C25?nm open mesopores by coating with nano-silica as a hard template followed by pyrolysis and dissolution of the silica. This left an open mesoporous surface to serve as a host for catalysts or enzymes while retaining integrity in the core for electrical and mechanical performance. The combination of these two methods could be used to make different hierarchical, multi-functional carbon structures which could be applied in fuel cells as the catalyst carrier and biofuel cell electrode.     

Preparation of ordered macroporous platinum and palladium powders

Ordered macroporous platinum and palladium metal powders were prepared with a combination of silica template and hydrogen reduction methods. The effects of species of metal precursor and calcination of silica templates on the structure of final metal powders were investigated. Precursor of platinum or palladium was infiltrated into closely packed silica templates prepared from tetraethyl orthosilicate and vacuum dried at room temperature following hydrogen reduction to obtain metal–silica complexes. After the removal of the silica templates from the complexes by hydrofluoric acid treatment, metal powders were obtained. Ordered macroporous platinum and palladium powders were obtained by using hydrogen hexachloroplatinate (IV) hexahydrate with uncalcined silica template and palladium (II) chloride with calcined templates, respectively. Composition analyses indicated that silica templates were completely removed from the ordered metal powder. Sizes of the voids in the ordered macroporous metal powders were controlled in the range of 240–520 nm corresponding to those of the silica spheres used.     

由稻壳炭合成介孔二氧化硅

以稻壳发电残渣稻壳炭的碱提取液为硅源,十六烷基三甲基溴化铵(CTAB)为模板剂,在碱性条件下通过溶胶-凝胶方法合成多孔二氧化硅前驱体。获得的前驱体采用萃取的方式脱除模板剂,合成产品采用低温氮气吸脱附、XRD、TEM、白度仪等手段进行了表征,确证得到的产品为高比表面、有序介孔二氧化硅。讨论了前处理和脱模方式对合成产物结构和性质的影响。     

Aerosol synthesis of macroporous silica adsorbents with high performance in paclitaxel purification from plant cell cultures

Macroporous spherical silica particles having high performance for the purification of paclitaxel were synthesized by spray pyrolysis using polystyrene nanoparticles as a template. In terms of increasing the purity and yield of paclitaxel, the synthesized macroporous silica showed the better performance than mesoporous silica of high surface area as well as commercial sylopute. The generation of macroporous with the sacrifice of losing surface area was proved to be helpful for enhancing the performance of adsorbents for paclitaxel purification. As a result, the high purity (67.3%) and yield (80.0%) of paclitaxel was achieved by using macroporous silica prepared by spray pyrolysis.     

3D cubic mesoporous silica microsphere as a carrier for poorly soluble drug carvedilol

The present work was proposed not only to exploit the potential of 3D cage-like mesoporous silica SBA-16 with a well-defined spherical morphology as a carrier for poorly soluble drugs, but also to compare the drug loading and release properties of 3D cubic SBA-16 with that of classic 2D hexagonal MCM-41. SBA-16 microsphere with highly ordered mesostructures was synthesized by a facile method using block co-polymer F127 as template, cetyltrimethylammonium bromide (CTAB) as co-template and tetraethyl orthosilicate (TEOS) as silica source. Carvedilol (CAR), an antihypertensive agent, was used as a model drug and loaded into mesoporous silica via solvent deposition method at drug-silica ratio of 1:3. In vitro dissolution was performed in both simulated intestinal fluid (SIF, pH 6.8) and simulated gastric fluid (SGF, pH 1.2). Of particular interest was that in SIF both MCM-41 and SBA-16 samples exhibited promoted dissolution profile for CAR as compared to its corresponding crystalline form which exhibited poor dissolution behavior. This dissolution-enhancing effect might be due to the non-crystalline state and increased surface area of confined CAR as well as the hydrophilic nature of silica. In comparison with MCM-41, SBA-16 displayed a more rapid release profile in both SIF and SGF, which may be ascribed to the 3D interconnected pore networks and the highly accessible surface areas. The suitability of the utilization of SBA-16 microsphere as carriers will open new avenues for the formulation of poorly soluble drugs.     

无皂乳液聚合制备三维有序聚合物大孔材料

采用氨催化水解正硅酸乙酯制备了单分散二氧化硅微球,通过透射电子显微镜观察微球的粒径及其单分散性。利用垂直沉积法制备二氧化硅胶体晶体,通过扫描电子显微镜观察其形貌,利用紫外-可见光分光光度计对其带隙结构进行表征。结合模板技术,采用无皂乳液聚合制得三维有序聚苯乙烯大孔材料,通过扫描电子显微镜观察结构的有序度。结果表明:聚苯乙烯大孔材料结构高度有序,形成开放的三维通道网络,为聚合物大孔材料在诸多领域的潜在应用提供了可能。     

Synthesis of Kenyaite, Magadiite and Octosilicate Using Poly(ethylene glycol) as a Template

Three types of layered silicates, namely octosilicate, magadiite and kenyaite, were synthesized using poly(ethylene glycol) (PEG). The influence of reaction parameters, including alkali source, silica source, PEG molecular weight, reaction time and temperature, on the formation of these three phases was investigated. The results indicate that magadiite is preferred when (i) using NaOH as the alkali source and at a lower temperature (150°C), with fumed silica, tetramethyl orthosilicate (TMOS), tetraethyl orthosilicate (TEOS), Ludox-AS 40 or colloidal sol acting as the silica source in the presence of PEG 200; (ii) using fumed silica as the silica source and PEG 300 as the template at 150°C; (iii) at a higher temperature (180°C), using PEG 200 as template and TEOS as the silica source; and (iv) at 180°C with a combination of PEG 300 and fumed silica. Compared to magadiite, kenyaite was favored at a higher temperature (180°C) with PEG 200 and NaOH, KOH or RbOH, while using fumed silica, silica gel, or colloidal sol as silica source; or at the lower temperature (150°C) using NaOH as alkali source, PEG 200 as template, and silica gel or silicic acid as the silica source. Octosilicate was obtained at 90°C with the combination of NaOH, PEG 200 and fumed silica.     

Preparation and Characterization of Confined Atactic Polystyrene in Ordered Silica/Polystyrene Composites

Ordered silica/polystyrene composites were prepared via radical polymerization in silica colloidal crystal templates, and ordered macroporous polymers were accordingly obtained after removing the silica templates. The confinement effect of the templates on the polymers in the composites was investigated. NMR results indicated that the polystyrenes formed both inside and outside the template were atactic. The polystyrene inside the template possessed a higher molecular weight and a narrower molecular weight distribution than the bulk one outside the template. The glass transition temperature of the confined polystyrene increased significantly with decreasing silica sphere size of the templates, and so did the contraction of polymer pores. The smaller the silica sphere size of the templates, the more remarkable is the confinement, which could be explained by entropic confinement of the polymer chains within a fixed inorganic meso‐framework (T. P. Russell, Science 2001 , 293, 446).     

邻苯二甲酸二辛酯印迹吸附树脂的制备及其吸附性能

以大孔吸附树脂D101为载体,丙烯酰胺为功能单体,乙二醇二甲基丙烯酸酯为交联剂,邻苯二甲酸二辛酯(DOP)为模板分子,制备了DOP分子印迹吸附树脂(DOP-MIP-D101),采用红外和扫描电镜等方法对其进行了表征。研究了DOP-MIP-D101对DOP的静态等温吸附性能、吸附动力学以及选择性吸附性能。结果显示,DOP-MIP-D101对DOP的吸附能力明显大于非印迹树脂(NIP-D101),且具有较高的选择性,吸附行为符合Freundilich方程。DOP-MIP-D101对DOP的吸附达到平衡的时间为100min左右。     

Large pore heavy oil processing catalysts prepared using colloidal particles as templates

Macroporous FCC catalyst and macroporous HDS catalyst were prepared using polystyrene spheres as template. The size of the macropores can be tailored by controlling the size of template. The BET surface area and the pore volume of the macroporous catalysts are larger than those of catalysts prepared without template, and the more template used, the larger the surface area and pore volume obtained. When the same amount of template was used, the smaller diameter template produced a catalyst with larger surface area and pore volume. The increments in surface area and pore volume of the catalysts were greater than those predicted from the geometry of the template, indicating particle template could inhibit the shrinkage of the catalyst during drying. When used as heavy oil FCC catalysts and heavy oil HDS catalyst, the prepared macroporous catalysts are much more active than catalysts prepared without the template.