Polyoxometalate-based silica-supported ionic liquids for heterogeneous oxidative desulfurization in fuels

With the aim of deep desulfurization, silica-supported polyoxometalate-based ionic liquids were successfully prepared by a one-pot hydrothermal process and employed in heterogeneous oxidative desulfurization of various sulfur compounds. The compositions and structures of the hybrid samples were characterized by various methods such as FT-IR, XPS, Raman,UV–Vis, wide-angle XRD and N2adsorption–desorption. The experimental results indicated that the hybrid materials presented a high dispersion of tungsten species and excellent catalytic activity for the removal of 4,6-dimethyldibenzothiophene without any organic solvent as extractant, and the sulfur removal could reach 100.0% under mild conditions.The catalytic performance on various substrates was also investigated in detail. After cycling seven cycles, the sulfur removal of the heterogeneous system still reached 93.0%. The GC-MS analysis results demonstrated that the sulfur compound was first adsorbed by the catalyst and subsequently oxidized to its corresponding sulfone.

Synthesis of some new bis-3,4-dihydropyrimidin-2(1H)-ones by using silica-supported tin chloride and titanium tetrachloride

Silica-supported tin chloride and titanium tetrachloride were prepared by the reaction of tin chloride and titanium tetrachloride with activated silica gel in refluxing toluene.These solid acids have been employed as the catalysts for the synthesis of bisdihydropyrimidin -2(1H)-ones from aromatic dialdehydes,1,3-dicarbonyl compounds and urea at 90℃under solvent-free conditions.

Hydrogenation of Toluidines Catalyzed by Silica-supported Carboxymethylcellulose-platinum Complex

The hydrogenation of toluidines catalyzed by silica-supported carboxymethyl cellulose platinum complex forms methylcyclohexlamines in high yields, such as m-toluidine to 3-methylcyclohexylamine, o-toluidine to 2-methylcyclohexylamine, and p-toluidine to 4-methylcyclohexylamine in 97%, 96.7% and 98.2% yields, respectively, at 30 ℃ and under atmospheric hydrogen pressure. The yields were remarkably affected by the Pt content in the complex, the kind of solvent and the reaction temperature. The catalyst was very stable and could be reused several times without remarkable change in the catalytic activity.

SYNTHESIS AND CHARACTERIZATION OF A SILICA-SUPPORTED CARBOXYMETHYLCELLULOSE PLATINUM COMPLEX AND ITS CATALYTIC BEHAVIORS FOR HYDROGENATI0N OF AR0MATICS

A silica-supported carboxymethylcellulose platinum complex (abbreviated as SiO_2-CMC-Pt) has been prepared and characterized by XPS. Its catalytic properties for hydro-genation of aromatic compounds were studied. The results showed that this catalystcould catalyze the hydrogenation of phenol, anisol, p-cresol, benzene and toluene to cyclo-hexanol, cyclohexyl methyl ether, p-methyl cyclohexanol, cyclohexane and methylcyclo-hexane, respectively in 100% yield at 30℃ and 1 atm. In the hydrogenation of phenol,COO/Pt ratio in SiO_2-CMC-Pt has much influence on the initial hydrogenation rate andthe selectivity for the intermediate product, cyclohexanone. The highest initial rate andthe highest yield of cyclohexanone both occur at COO/Pt ratio of 6. The complex is stableduring the reaction and can be used repeatedly.

HYDROFORMYLATION OF MMA CATALYZED BY SILICA-SUPPORTED POLY-γ-AMINO PROPYLSILOXANE-Rh-Co BIMETALLIC COMPLEX

A silica-supported poly-γ- aminopropylsiloxane-rhodium-cobalt bimetallic complex(abbreviated as SiO_2-NH_2-Rh-Co)has been prepared and used as catalyst for hydroformylationof methyl methacrylate. The results showed that the catalyst could catalyze the reaction in95.6% conversion with 92.8% selectivity for the normal aldehyde, methyl β-formylisobu-tyrate. Such catalyst also showed high stability during the reaction and could be used repeat-edly.

Synthesis of Methyl-(γ-chloropropyl)dichlorosilane Catalyzed by Silica-supported Karstedt-type Catalyst

Methyl-（γ-chloropropyl）dichlorosilane was synthesized under the catalysis of a silicasupported Karstedt-type catalyst. By orthogonal experimental design method, the optimum reaction parameters such as reactants ratio, reaction temperature and time, and the dosage of catalyst, were determined. At the optimum reaction condition the product yield reached 78.42%, which is higher than that reported in the literatures.

PW_(12)/g-C_3N_4光催化降解甲基橙

采用浸渍法制备了磷钨酸(PW12)/g-C3N4复合光催化剂,并将其用于溶液中甲基橙的光催化降解,运用IR技术对使用前后的光催化剂进行了表征。表征结果显示,PW12和g-C3N4的结构未在浸渍负载中发生改变,且PW12和g-C3N4结合牢固。实验结果表明:最佳的PW12负载量(光催化剂中PW12的质量分数)为50%;光催化降解甲基橙的优化反应条件为初始甲基橙质量浓度5 mg/L、光催化剂加入量0.6 g/L、初始溶液p H=7;在优化条件下,分别采用紫外光、模拟太阳光、可见光照射120 min后,甲基橙的降解率分别为96.59%,82.23%,42.78%;该光催化剂固载良好,使用中不易发生溶脱,稳定性好,可重复使用。

H_3PW_(12)O_(40)/Al_2O_3催化合成丙烯醛

采用等体积浸渍法制备了具有Keggin结构的杂多酸H3PW12O40/Al2O3催化剂,用IR、XRD、BET等方法对催化剂进行了表征。同时利用常压连续流动的固定床反应器考察该催化剂对甘油制备丙烯醛的工艺条件,重点考察了催化剂的种类、杂多酸的负载量、反应温度等条件对反应的影响。结果表明,由甘油制备丙烯醛的较优条件为:当催化剂为H3PW12O40/Al2O3,负载量为40%,反应温度为330℃时,丙烯醛的选择性可达83.7%,甘油的转化率为100%。

甲烷部分氧化反应的磷钨酸催化剂研究

以磷钨酸为催化剂和氧化剂,进行了无氧条件下的甲烷气固相部分氧化的实验研究,考察了磷钨酸催化剂的制备条件、载体影响以及反应温度对甲烷部分氧化反应的影响等。磷钨酸催化剂可有效催化甲烷部分氧化反应,甲烷首先转化生成醋酸甲酯,醋酸甲酯水解生成甲醇。制备的催化剂以SiO2为载体,采用载体质量15%（wt）的磷钨酸水溶液回流浸渍4h、120℃干燥2h、300℃焙烧4h制得。甲烷部分氧化反应在0.10MPa、267-280℃进行,甲烷转化率为26.61%,目的产物收率25.82%。

磷钨酸/SiO_2负载化光催化剂的制备与表征

以溶胶–凝胶法合成的SiO2作载体,固载磷钨酸制得负载化磷钨酸光催化剂,用XRD、FT-IR、UV-Vis-DRS等方法表征了催化剂的理化性能。结果表明,所制备的负载化磷钨酸催化剂对甲基橙的光催化降解反应具有较好的催化性能。

磷钨酸催化剂部分氧化甲烷合成甲醇的探索性实验研究

以磷钨酸为催化剂，进行了甲烷部分氧化制取甲醇的实验研究。实验在常压微分反应器上进行，醋酸为液相试剂，甲烷首先转化生成醋酸甲酯，醋酸甲酯水解生成甲醇。考察了磷钨酸催化剂的制备方法、制备条件、载体影响以及反应温度对甲烷部分氧化反应的影响。磷钨酸催化剂可有效催化甲烷部分氧化反应。当催化剂采用回流浸溃法制备，SiO2为催化剂载体，催化剂焙烧温度为300℃，催化活性诱导期为3～4h。甲烷部分氧化反应在0．1MPa、267～280℃条件下，甲烷转化率为26.61％，目的产物选择性97．26％。

二氧化硅负载磷钨酸催化罗汉柏木烯的异构反应

甲基柏木酮为柏木系最重要的香料之一,具有珍贵的木香-麝香-龙涎香气息,其中Isomer G成分的香气最为出色,它是由罗汉柏烯先异构为Olefin B,再乙酰化得到。采用溶胶-凝胶法制备二氧化硅负载磷钨酸固体催化剂制备Olefin B,研究磷钨酸负载量、焙烧温度和焙烧时间对催化剂活性的影响,用比表面积及孔径分析(BET)、X-射线多晶衍射(XRD)进行表征;通过单因素及正交试验优化罗汉柏木烯异构反应工艺,并用气相色谱-质谱(GC-MS)联用仪对产物进行表征。研究表明:催化剂制备最佳工艺条件为磷钨酸负载量40%、焙烧温度200℃和焙烧时间3 h时,催化活性最强;异构化单因素最佳条件为反应温度70℃、反应时间7 h、溶剂质量分数50%和催化剂质量分数10%;正交试验最佳工艺条件为反应温度80℃、反应时间7 h、乙酸质量分数50%和催化剂质量分数10%,平均得率58.1%,产物Olefin B(7,10-桥亚乙基-4,4,7-三甲基-1,9-八氢化萘)的选择性为97.7%,催化剂可循环使用3次。

润滑油季戊四醇月桂酸酯无溶剂合成工艺研究

采用溶胶一凝胶法制备了硅胶负载磷钨酸型催化剂，利用IR、XRD、TG／DTG技术，对催化剂进行表征，结果表明，磷钨酸成功负载在硅胶上，热稳定性良好。在无溶剂条件下，利用硅胶负载磷钨酸催化合成了季戊四醇月桂酸酯，通过实验，探讨了催化剂中磷钨酸的负载量、反应时间、反应温度、催化剂用量、酸醇摩尔比以及催化剂重复使用次数对酯化率的影响，当磷钨酸的负载量为71．59％，反应时间为4h，反应温度160～200℃，催化剂用量为反应物总质量的1．5％，月桂酸与季戊四醇的摩尔比为4：1时，酯化率可达84．92％以上，且催化剂重复使用性好。所得季戊四醇月桂酸酯产品外观色泽较浅，其结构经红外光谱进行了确认。

杂多酸催化合成α-甲基丙烯酸月桂醇酯

用磷钨酸为催化剂 ,以α -甲基丙烯酸和月桂醇为原料合成了α -甲基丙烯酸月桂酯。研究了杂多酸的用量、反应温度、反应时间、酸醇摩尔比等因素对酯收率的影响。结果表明 :此法催化剂用量少、催化活性高、反应时间较短、酯收率较高、工艺较简单 ,最佳工艺条件是 :醇 /酸摩尔比为 1.5 :1,催化剂用量为反应物质量0 .4% ,带水剂甲苯用量为反应物质量的 2 4% ,反应温度为 15 5℃ ,反应时间 2h ,此条件下 ,酯收率为 85 %。

蛋鸡血清载脂蛋白AI的分离纯化及鉴定

介绍了一种分离纯化蛋鸡血清载脂蛋白AI的一种新方法。用磷钨酸沉淀制备鸡血清HDL,乙醇/丙酮(体积分数ψ=1)脱脂后经sephadexG-150凝胶层析柱反复层析。获得的apoAI经12.5%的SDS-PAGE电泳显示为单一条带,分子量测定大约为27788Da。本方法的优点是通过使用磷钨酸沉淀法代替了超速离心的繁琐过程,在一般实验室条件下,缩短了制备时间且分离效果好。

Dawson型磷钨酸催化合成乳酸月桂醇酯

用Dawson型磷钨酸催化合成乳酸月桂醇酯.实验结果表明:Dawson型磷钨酸有较高的催化活性,反应时间短,酯收率高,工艺简单.最佳工艺条件为:醇/酸摩尔比为1.5:1,催化剂用量为0.3%,带水剂甲苯体积(mL)与反应物质量(g)之比为0.4:1～0.5:1,反应温度为115～140℃,反应时间30～50min.在此条件下,酯收率可超过93% .

HYDROGENATION OF PHENOL AND CRESOLS CATALYZED BY CHITOSAN SUPPORTED PALLADIUM COMPLEX AT MILD CONDITIONS

A natural polymer catalyst, silica-supported chitosan palladium complex (abbr. as SiO2-CS-Pd) was found to catalyze the hydrogenation of phenol and cresols to corresponding cyclohexanones in high yield and 100% selectivity at 70 degrees C and 1.01325 x 10(5) Pa mild conditions. N/Pd molar ratio in the complex, temperature and solvents have much influence on the reaction. The reactivity order of reactants was found to be: phenol >m->p->o- The catalyst is stable during the reaction and could be repeatedly used for several times without much decrease in its catalytic activity.

Amine facilitates the synthesis of silica-supported ultrasmall bimetallic nanoparticles

Supported catalysts based on metal nanoparticles are a class of widely used heterogeneous catalysts in industry.The catalytic performances of supported metal catalysts are highly determined by many parameters of metal nanoparticles such as their particle size,composition,surface structure and also interfacial interaction with supports[1].Supported metal catalysts are

Sulfuric Acid Immobilized on Silica Gel as Highly Efficient and Heterogeneous Catalyst for the One-Pot Synthesis of 2,4,5-Triaryl-1H-imidazoles

Application of sulfuric acid immobilized on silica gel as an efficient and benign catalyst has been explored in the syn-thesis of 2,4,5-Triaryl-1H-imidazoles via condensation reaction of benzil or benzoin, aldehyde and ammonium acetate. The key advantages of this process are high yields, cost effectiveness of catalyst, easy work-up, purification of products by non-chromatographic method and the reusability of the H2SO4.SiO2 catalyst.