α-SiW11Ni/PANI光催化降解染料废水的研究

以α-SiW11Ni/PANI为催化剂,在紫外灯辐射下,研究了模拟染料废水亚甲基蓝溶液的光催化降解的反应,讨论了催化剂投加量、亚甲基蓝溶液的初始浓度、酸度等对催化脱色效果的影响。实验结果表明,100 mL的亚甲基蓝溶液在紫外灯辐射下最佳的浓度为5 mg/L,催化剂用量为110 mg/L,溶液酸度为pH2;在不改变溶液酸度的情况下,外加氧化剂H2O2能够显著加速亚甲基蓝的催化降解效果。     

PW_(12)/PANI/ZnO复合材料光催化降解亚甲基蓝

以PW12/PANI/ZnO为光催化剂。在紫外灯辐射下,研究了模拟染料废水亚甲基蓝溶液的光催化降解的反应,讨论了催化剂投加量、染料浓度、溶液的pH值对亚甲基蓝降解率的影响。结果表明,亚甲基蓝溶液光催化降解的最佳条件为:pH=3,催化剂投加量为0.012 5 g,染料浓度为5 mg/L,经30 W紫外灯照射90 min后,其降解率为85.84%。     

PW/MCM-41光催化性能研究

以浸渍法制备了负载型光催化剂PW/MCM-41,并对催化剂进行了表征,考察了催化剂在光催化模拟染料废水亚甲基蓝(MB)溶液降解反应中的催化活性.实验结果表明:催化剂负载量为30％、催化剂投加质量浓度为3.0g/L、MB溶液的初始质量浓度为10 mg/L、pH=5、光照时间100 min时,对亚甲基蓝降解率可达91％以上...     

硫化锌/磷酸铝分子筛的光催化性能研究

通过水热合成法,成功合成出硫化锌/磷酸铝分子筛(ZnS/APO)复合材料。采用XRD、FT-IR等技术对所合成的复合材料进行理化性能表征。考察了不同光源条件催化剂的活性。并以可见光光催化降解亚甲基蓝反应为探针反应,考察了催化剂在不同的反应条件下对亚甲基蓝的降解效果。研究结果表明,在中性或碱性溶液中,催化剂循环利用7次,对亚甲基蓝溶液仍有良好的光催化活性。     

Cu_2O/蒙脱土复合催化剂的制备及其光催化性能

本文以化学沉淀法制备了Cu_2O/蒙脱土复合光催化剂,以亚甲基蓝的光催化降解为探针反应测试了Cu_2O/蒙脱土复合催化剂的光催化活性,并研究了Cu_2O的负载量、复合催化剂用量、溶液pH值和亚甲基蓝初始浓度等对Cu_2O/蒙脱土复合催化剂光催化活性的影响。研究结果表明pH=11、50%Cu_2O/蒙脱土复合催化剂投加量为0.2g/L、亚甲基蓝溶液浓度为10mg/L时,可见光照射120min后,降解效率可达到91%。     

TiO_2负载杂多酸光催化降解亚甲基蓝的研究

以TiO_2负载杂多酸β-SiW_(12)/TiO_2为光催化剂。研究了其对亚甲基蓝模拟染料废水的光催化降解性能,讨论了亚甲基蓝溶液的酸度、亚甲基蓝溶液的初始浓度以及催化剂β-SiW_(12)/TiO_2投加量等对亚甲基蓝溶液脱色效果的影响.结果表明,β-SiW_(12)/TiO_2加入量为12 mg,亚甲基蓝的初始浓度为30 mg/L,pH值=6,脱色率达到86.79%。     

PW_(11)/PANI/TiO_2复合材料光催化降解亚甲基蓝的研究

以PW11/PANI/Ti O2为光催化剂,研究了不同条件对亚甲基蓝光催化降解效果的影响,如改变亚甲基蓝溶液的起始浓度、调节溶液的起始p H值和催化剂的用量等。结果表明,亚甲基蓝溶液光催化降解的最佳条件为染料的起始质量浓度为10 mg/L,p H值为3,催化剂的最佳用量为7.5mg,可达90.12%的脱色率。该催化剂对亚甲基蓝染料的降解为一级动力学反应。     

磷钼酸铋光催化降解亚甲基蓝

采用微波固相法,以硝酸铋、钼酸铵、磷酸二氢铵为原料合成了磷钼酸铋,用FT-IR、XRD、PL等对磷钼酸铋的结构和电子-空穴对的复合性能进行表征。在紫外光下降解亚甲基蓝为研究对象,考查磷钼酸铋光催化剂的光照时间、催化剂用量、亚甲基蓝初始浓度、亚甲基蓝初始酸度等因素对亚甲基蓝降解的影响。实验结果表明:合成的磷钼酸铋具有Keggin结构,通过降低光生电子和空穴的复合几率,提高催化剂的光催化活性。在紫外光照射时间60min,催化剂用量为0.6g,亚甲基蓝溶液初始浓度为20mg/L,溶液的pH值为5时,亚甲基蓝降解率可达98.4%。     

SnWO4/g-C3N4复合光催化剂降解亚甲基蓝溶液

采用溶剂热法制备SnWO_4/g-C_3N_4复合光催化剂,在可见光降解亚甲基蓝实验中研究复合催化剂的光催化性能。考察催化剂投加量、亚甲基蓝溶液初始浓度、溶液pH值、盐效应对光催化性能的影响及SnWO_4/g-C_3N_4复合光催化剂的重复利用性。实验结果表明,在催化剂投加量1.0 g·L~(-1)、亚甲基蓝溶液初始浓度15 mg·L~(-1)和溶液pH值7.08时,在可见光条件下反应3 h,亚甲基蓝溶液脱色率达到94.2%;NaCl对光催化降解亚甲基蓝具有抑制作用,加入10 mmol·L~(-1)的NaCl溶液后亚甲基蓝的脱色率降为76.0%;复合光催化剂循环使用5次后,暗吸附后光照3 h,亚甲基蓝溶液的总脱色率仍可达到78.7%,重复利用性良好。     

AgBr/Zn_3(OH)_2V_2O_7·2H_2O可见光催化降解亚甲基蓝溶液

采用水热和沉淀两步合成法制备AgBr/Zn_3(OH)_2V_2O_7·2H_2O催化剂,研究其在可见光下降解亚甲基蓝溶液的性能,并考察催化剂用量、亚甲基蓝溶液初始浓度、p H值以及盐浓度对光催化性能的影响,评价AgBr/Zn_3(OH)_2V_2O_7·2H_2O催化剂的重复使用性能。结果表明,在前驱液pH为10、120℃水热10 h、Ag与Br物质的量比为0. 20条件下制备的复合催化剂在可见光下反应120 min后,1. 0 g·L~(-1)的催化剂对10 mg·L~(-1)的亚甲基蓝溶液脱色率达到85. 2%。NaCl对亚甲基蓝的降解起抑制作用,Na_2SO_4对亚甲基蓝的降解起促进作用。催化剂重复使用4次后,光照120 min后的亚甲基蓝溶液脱色率可达66. 4%。催化剂对不同初始浓度亚甲基蓝溶液的光催化降解符合一级动力学模型。     

meso-四(4-N-乙基吡啶基)金属卟啉催化剂的合成及其催化活性的表征

采用两条路线合成了季铵阳离子型的meso-四(4-N-乙基吡啶基)卟啉和对应的铁、钴,铜,锌,锰等几种金属配合物催化剂,采用UV-Vis、IR、MS和EA等对其结构进行了表征.同时,采用碱性甲醇溶液中氧气氧化对硝基甲苯制备对硝基苯甲酸作为模型反应,对上述催化剂的催化性能进行了表征,发现这些催化剂均有显著的活性.其中溴化...     

The catalytic activity of immobilized on modified silica metalloporphyrins bearing antioxidative 2,6-di-tert-butylphenol pendants

A comparative study of the catalytic activity of supported manganese(III) and iron(III) chlorides of meso-tetrakis(3,5-di-tert-butyl-4-hydroxyphenyl)porphyrin (R₄PMnCl, R₄PFeCl) and meso-tetraphenylporphyrin (TPPMnCl, TPPFeCl) is reported. The metalloporphyrins have been immobilized via coordination bond on the surface of two series of imidazole modified silica, imidazole propyl silica (IPS) and imidazole 3-(glycidyloxypropyl) silica (IGOPS). The heterogenised catalysts have been evaluated for hydrocarbon oxidation by sodium periodate. The critical role of 2,6-di-tert-butylphenol groups on the periphery of porphyrin ring in their catalytic activity has been evaluated and pertinent structural and mechanistic aspects are discussed.     

取代基及中心金属离子对卟啉电子结构及催化活性的影响

通过调变取代基及中心金属离子种类调控金属卟啉的微观分子结构和宏观性质与功能是设计高活性、高选择性的金属卟啉催化剂的关键及富有挑战性的课题。取代基和中心金属离子对金属卟啉电子结构性质的影响研究可为金属卟啉催化剂的精确设计提供重要的理论依据。采用基于密度泛函理论计算化学方法系统地研究了不同取代基(-OCH₃、-CH₃、-H、-NO₂)及中心金属离子(Mn、Fe、Co、Cu、Zn)对卟啉电子结构性质的影响,试图从本质上理解金属卟啉微观结构和宏观催化性能的关系。结果表明,吸电子基-NO₂总是降低金属卟啉的最高占据轨道(HOMO)和最低未占据轨道(LUMO)能级,而供电子基-CH₃和-OCH₃总是升高金属卟啉的HOMO和LUMO能级。变价金属(Mn、Fe、Co)卟啉的前线分子轨道主要由金属离子的3 d轨道组成,有利于活化分子氧。不变价金属(Cu、Zn)卟啉的前线分子轨道的成分为卟啉配体形成的大π键,电子流动性好,故不变价金属也有较高的催化活性。Fukui函数分析表明变价金属卟啉的活性中心位于中心金属离子,而不变价金属卟啉的活性中心可能在卟啉配体上。     

Metalloporphyrins as catalysts in the decomposition of cyclohexyl hydroperoxide

A series of metalloporphyrins with various metals were tested as catalysts in the decomposition of cyclohexyl hydroperoxide. The more active complexes are those of manganese(III), iron(III), chromium(III) and ruthenium(II). No relation could be found between the redox potentials of the catalysts and their activity.This work is part of the thesis by C.B. Hansen, Utrecht, 1991.     

Metalloporphyrins encapsulated mesoporous molecular sieves as efficient heterogeneous catalysts for oxidation of cyclohexene with iodosylbenzene

The cationic Fe, Mn or VO porphyrins were encapsulated in Si, Al, Ti and V-MCM-41. The catalytic activity was investigated for the oxidation of cyclohexene with iodosylbenzene (PhIO) as oxidant. Manganese porphyrin supported catalysts produces epoxide as major products whereas iron and vanadyl porphyrins gave allylic oxidation products as major constituents. The results obtained clearly shows that the selectivity of various products depends not only on the nature of the support materials but also on the combined effects of metalloporphyrins and the supports. The recyclability of the heterogeneous catalysts was also investigated. The decrease in catalytic activity and leaching of active centers were observed when porphyrins were supported on Si-MCM-41.     

Selective catalysis of μ-oxo-bismetalloporphyrins for 2-methylbutane oxidation with PhIO under mild conditions

Fourteen μ-oxo-bisironporphyrins and nine μ-oxo-bismanganeseporphyrins were synthesized, and their selective catalysis for the oxidation of the secondary and tertiary carbon–hydrogen bonds of 2-methylbutane with PhIO were also studied. The ratio of the relative reaction selectivity of tertiary carbon–hydrogen bonds to secondary carbon–hydrogen bonds was 3:1 when ironporphyrins were used as catalysts, and 4:1 when manganeseporphyrins were used as catalysts. The research showed that the substituents on the porphyrin rings influenced the catalytic selectivity of metalloporphyrins for the oxidation of the secondary and tertiary carbon–hydrogen bonds as well as the reaction rate. Whether ironporphyrins or manganeseporphyrins, the electron-attracting groups on porphyrin rings increased the catalytic selectivity of metalloporphyrins for the tertiary carbon–hydrogen bonds and the reaction rates, however, the electron-releasing groups increased the catalytic selectivity of metalloporphyrins for secondary carbon–hydrogen bonds, but reduced the reaction rates.     

锰卟啉-醋酸钴复合催化体系对甲苯氧气氧化的催化作用

研究了在无溶剂体系中,对氯四苯基锰卟啉［T(p-Cl)PPMnCl］和醋酸钴［Co(OAc)2］复合催化下,空气氧化甲苯制苯甲醛、苯甲醇和苯甲酸的新工艺。实验发现,T(p-Cl)PPMnCl/Co(OAc)2为复合催化剂时比单独使用T(p-Cl)PPMnCl 或Co(OAc)2时有更高的甲苯转化率和苯甲醛、苯甲醇、苯甲酸的收率,表现出明显的复合催化作用。研究表明,反应温度、反应时间和催化剂比例对T(p-Cl)PPMnCl/Co(OAc)2的复合催化效果有影响。     

金属卟啉催化空气氧化甲基环己烷制备甲基环己醇和甲基环己酮

报道了通过金属卟啉选择性催化空气氧化甲基环己烷制备甲基环己醇和甲基环己酮的方法.在金属锰卟啉催化下,甲基环己烷被空气氧化为3种甲基环己酮的异构体、1-甲基环己醇和2-甲基环己醇.考察了不同反应条件和金属卟啉结构对甲基环己烷氧化反应转化率和选择性的影响.与四苯基锰卟啉相比较,烷氧基取代的金属锰卟啉为催化剂时,虽然反应转化率降低了,但明显提高了甲基环己醇和甲基环己酮的选择性.且金属上的取代基团体积越大,反应的转化率越高,同时选择性较高.以金属卟啉5,10,15,20-四(对庚烷氧基苯基)锰卟啉为催化剂,反应的转化率可以达到20%,甲基环己醇和甲基环己酮的总选择性为76%.     

环己烯分子氧氧化多相催化剂研究进展

根据催化剂主组分的不同,综述了国内外环己烯分子氧氧化多相催化剂的研究进展;主要介绍了钴系、锰系、铁系及镍系催化剂在环己烯分子氧氧化中的应用及其优缺点.指出负载型纳米金催化剂与传统的钴、锰催化剂相结合制备双活性中心催化剂在环己烯分子氧氧化中有较好的应用前景.     

The use of various metal carbonyls as catalyst precursors for coal hydroliquefaction

The catalytic activity of metal carbonyl complexes of chromium, molybdenum, tungsten, manganese, iron, cobalt, and nickel in the liquefaction of coal (Illinois No. 6, Wandoan and Mi-ike) was investigated. The carbonyl compounds of molybdenum, tungsten, iron, cobalt, and nickel acted as highly active catalysts for the liquefaction of Illinois No. 6 coal, resulting in high coal conversion (>90%) and high oil yield (>32%), under hydrogen pressure of 50 kg cm^?1 in a nonhydrogen-donating solvent at 425°C for 60 min. Among the catalysts surveyed, Mo(CO)₆ gave the highest oil yield (57.7%) and the largest amount of hydrogen transferred to coal (3.1 wt.% of d.a.f. coal). However, the molybdenum and tungsten carbonyls did not exhibit high catalytic activity for low sulfur Wandoan coal in the absence of added sulfur. On the other hand, cobalt and nickel carbonyls showed high catalytic activity irrespective of the amount of sulfur in the reaction system. Fe(CO)₅Mo(CO)₆ binary catalyst promoted hydroliquefaction of Wandoan coal, resulting in increases in oil yield and transfer of hydrogen to coal in the presence of sulfur.