Dawson型磷钼钒杂多酸催化合成1,3-二噁戊烷的研究

考察了Dawson型磷钼钒杂多酸和各种结构反应底物对1，3-二噁戊烷合成催化活性的影响．研究表明：H6P2Mo17VO62的催化效果最好，反应条件温和，环氧化物的转化率接近100％，1，3-二噁戊烷的选择性在90％以上。     

两种方法制备竹炭基固体磺酸催化缩酮反应的研究

用两种方法制备竹炭基固体磺酸,研究两种竹炭基固体磺酸对催化缩酮反应的影响;考察催化剂的不同制备方法对催化效能的影响,同时考察催化剂用量、酮醇比、不同底物对转化率的影响。实验结果表明:合成缩酮的最佳反应条件是采用30%磷酸浸泡48 h处理的催化剂,固体磺酸用量相对于酮2%mol(酸量),酮醇摩尔比为1∶2,酮平均转化率可达90%以上;竹炭基固体磺酸对缩酮类化合物的合成具有良好的催化效果和稳定的催化性能。     

Co4HP2Mo15V3O62的合成及其催化乙苯氧化反应性能

合成了一系列Dawson型磷钼钒钴杂多酸盐Co<,n> H<,9-2n>P<,2>Mo<,15>V<,3>O<,62>(n=1-4),用傅立叶变换红外光谱表征了磷钼钒钴的结构.以乙苯为原料、H<,2>O<,2>为氧化剂、磷钼钒钴杂多酸盐为催化剂催化氧化乙苯制备苯乙酮.考察了催化剂种类及用量、助剂用量、H<,2>O<,2...     

Keggin型多元杂多酸催化合成苯乙酮环乙二缩酮

合成了一系列具有Keggin结构的P-V-Mo-W四元杂多酸H3+xPVxMoyW12-x-yO40.nH2O(其中,x=1,2和3),采用傅里叶变换红外光谱和X射线衍射等方法表征了杂多酸的结构;以磷钒钼钨杂多酸为催化剂合成苯乙酮环乙二缩酮.考察了催化剂的种类、醇酮摩尔比、带水剂的种类和反应条件(催化剂用量、带水剂用量、反应温度、反应时间)对苯乙酮乙二醇缩酮反应的影响.在优化条件下,即苯乙酮0.1 mol、乙二醇0.14 mol、催化剂H6PV3MoW8O400.4 mmol、在110℃反应6 h、带水剂环己烷15 mL,苯乙酮的转化率达到84.1%、苯乙酮环乙二缩酮的选择性达到99.4%.     

Dawson结构磷钼钒酸铯催化H_2O_2氧化苯合成苯酚

采用乙醚反萃取方法合成了Dawson结构磷钼钒酸H8P2Mo16V2O62,进而与碳酸铯反应得到Dawson结构磷钼钒酸铯催化剂CsnH8-nP2Mo16V2O62(n=1-5),利用X射线粉末衍射(XRD)、红外(FTIR)以及SEM等对催化剂进行分析,并以H2O2为氧化剂,评价其在苯液相氧化直接羟基化合成苯酚反应中的催化性能,系统的研究了反应时间、催化剂用量、H2O2用量、反应溶剂等反应条件对催化反应的影响。结果表明,合成Cs3H5P2Mo16V2O62在催化反应中表现出优良的催化活性,优化条件下,苯酚收率达到31.0%;催化剂回收方便,可多次重复使用,在反应过程中,催化剂的Dawson结构没有明显变化。     

无溶剂超声辐射下Dawson型磷钨钒杂多酸催化合成螺杂双环衍生物

在Dawson型磷钨钒杂多酸催化下,芳香醛、尿素和2,2-二甲基-1,3-二噁烷-4,6-二酮或巴比妥酸衍生物无溶剂条件下超声辐射合成了12种螺杂双环衍生物.当催化剂的用量的摩尔分数为5%时,80℃反应15~45 min,收率为83%~94%.此外,还探讨了Dawson型磷钨钒杂多酸的催化机理.该方法具有条件温和,反应时间短且收率高的优点.催化剂对环境友好且可循环利用.     

硅钨酸掺杂的聚苯胺：实物模板法制备及催化性能

以不同形态的实物为模板,硅钨酸为掺杂剂,过硫酸铵为氧化剂合成了不同微观形貌掺杂态聚苯胺,并用红外光谱、气相色-质联用仪及扫描电镜对其进行了表征。考察了所制备的聚苯胺催化合成环己酮1,2-丙二醇缩酮的性能,探讨了不同微观形貌掺杂态聚苯胺催化剂对缩酮反应的催化活性,研究了催化剂用量、反应时间等因素对产品收率的影响,以及不同沸程的产物。结果表明:硅钨酸掺杂聚苯胺是合成环己酮1,2-丙二醇缩酮的良好催化剂,其中微观结构为球状的聚苯胺催化性能最佳。在n环己酮∶n1,2-丙二醇=1∶1.4,催化剂用量为反应物总质量的1.6%,反应时间为40 min的最佳条件下,环己酮1,2-丙二醇缩酮的收率为89.2%。     

磷钨钒杂多酸对甲基丙烯酸甲酯的阻聚作用

利用DSC法测定了Dawson型和Keggin型磷钨钒杂多酸对甲基丙烯酸甲酯的阻聚效果. 研究结果表明, 对同一种杂多酸而言, 随着杂多酸样品用量的不断增加, 反应的速率常数不断减小, 阻聚性能提高. 对于不同的杂多酸而言, 随着杂多酸中钨原子与钒原子数目比例的降低, 反应的数率常数随之减小, 说明含钒原子数越多的杂多酸阻聚性能越好. 总体上, Dawson型磷钨钒杂多酸的阻聚性能要优于Keggin型的.     

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% 。     

钒钼协同作用下杂多酸催化阻聚甲基丙烯酸甲酯

利用一锅法制备了Dawson型钨磷酸和钼钒磷酸,并用红外光谱和X-射线衍射表征了其结构.采用沸腾法研究了合成的杂多酸对甲基丙烯酸甲酯(MMA)的催化阻聚性能,考察了杂多酸结构、杂多酸用量和反应温度等因素对MMA本体聚合反应的影响.结果表明:钒钼元素在杂多酸催化阻聚MMA的反应中具有明显的协同作用,而且,杂多酸对MMA的催化阻聚作用随钒原子数的增加而增强,杂多酸的用量和反应温度对MMA自聚反应的速率影响较大.在过氧化苯甲酰(BPO)为0.04 g,MMA为10 mL,H9P2Mo15V3O62质量为MMA的0.06%,反应温度为101.2℃或H9P2Mo15V3O62质量为MMA的0.03%,反应温度为89.4℃时,MMA自聚反应被抑制.与传统和常用酚阻聚剂相比,Dawson型钼钒磷酸具有阻聚效果好、后处理简单、无腐蚀和污染问题等优点,能够作为MMA的阻聚剂使用.     

Dawson结构钼磷酸的合成与表征

合成了H_6P_2Mo_(18)O_(62)杂多酸及其四丁基铵盐和四丁基鏻盐,用IR、~(31)P NMR、GV等手段核查其纯度并研究了热稳定性、酸性和氧化还原性。结果表明,Dawson结构钼磷酸较Keggin结构钼磷酸有更强的氧化性。     

两种结构钼磷酸的催化氧化行为

考察了Dawson与Keggin结构钼磷酸的催化氧化行为,并与结构特性进行了关联,结果发现,Dawson结构的杂多酸对氧化脱氢及插入氧反应均有更高的活性。     

不同反荷离子的Keggin结构钼磷酸盐的热稳定性及其对异丁醛催化氧化活性的影响

用共沉淀法制备了以Keggin结构为骨架的不同反荷离子钼磷酸盐,利用FTIR、XRD等手段进行了表征。结果表明,Li、Na、K、Cs分别作为反荷离子时的杂多酸盐的热稳定性依次增强,并考察了催化剂对异丁醛一步氧化制甲基丙烯酸的催化活性,其中Cs盐的催化活性最优。     

Mixed-addenda vanadium-substituted polyfluorooxometalates: synthesis, characterization, and catalytic aerobic oxidation

For the first time, mixed-addenda vanadium-substituted polyfluorooxometalates, PFOMs, have been synthesized. Depending on the workup procedure used, two types of compounds were prepared. The first PFOM was a quasi Wells--Dawson type compound, [H2F6NaVVW17O56]8-, and the second a mixture of vanadium-substituted polyfluorooxometalates of the Keggin structure, XVIVW11FnO40 - n (X = H2, V, W; n = 1-4). From the X-ray diffraction analysis, [H2F6NaVVW17O56]8- has an elliptic (egg) shape with a central sodium atom surrounded by six fluorine atoms in a trigonal prism coordination. One may differentiate between two types of addenda atoms to be found in belt and capped positions. According to 1H, 19F, and 51V NMR analysis, it is concluded that vanadium is isomorphically substituted in both the belt and capped position of [H2F6NaVVW17O56]8-. The mixture of vanadium-substituted PFOMs of the Keggin structure was shown, by HPLC and ESR, to contain at least two species of different charge and of a different vanadium environment. The [H2F6NaVVW17O56]8- PFOM was active for the catalytic aerobic oxidation of alkyl aromatic compounds in biphasic (water-catalyst and substrate) media. The reaction selectivity (autoxidation versus oxydehydrogenation) depended on the substrate and reaction conditions such as temperature and oxygen pressure. The selectivity to oxydehydrogenation was significantly higher compared to the prototypical cobalt acetate catalytic system.     

Extraction of reduced molybdophosphoric and molybdoantimonylphosphoric acids with oxygenated solvents

The extractability of reduced molybdophosphoric acid and molybdoantimonylphosphoric acid depends principally on the solution acidity and the solvent. The effect of acidity is not related to the formation equilibria or stability of the heteropoly acids in the ranges studied (0.0003–2.5 M). A number of solvents extract independently of acidity, which suggests that suppression of dissociation is not a major factor. In certain instances, extraction is related to the ionic strength and acidity rather than just the acidity. The solvent influence can be related to its basicity or ability to solvate the heteropoly anion; Generally, the less basic the solvent, the greater the acidity or ionic strength must be to reach maximal extraction. The effect is probably one of dehydration or salting-out. Butyl acetate and acetophenone appear to be the best choices as extractants for reduced molybdoantimonylphosphoric acid based on minimal mutual solubility, acidity dependency, and extraction efficiency.     

Controllable one-step synthesis of ZnO nanostructures using molybdophosphoric acid

ZnO nanostructures were synthesised in a hydrothermal reaction of zinc acetate in the presence of molybdophosphoric acid (H₃[PMo₁₂O₄₀]) as well as its vanadium-substituted acid (H₄[PMo₁₁VO₄₀]) at various times, temperatures, and concentrations. The ZnO nanostructures were characterised by X-ray diffraction, transmission electron microscopy, and Fourier transform infrared spectroscopy. The results demonstrated that the synthesised products are crystalline with a zincite hexagonal phase. Various ZnO nanostructures, such as nanoparticles, microrods, and nanosheets, were produced by changing the experimental conditions. The photocatalytic degradation of methyl orange was also investigated using the ZnO nanoparticles thus prepared. These particles exhibited high performance in the photocatalytic degradation of MO and almost 100 % decolourisation occurred within only 20 min.     

温控Noyori配体的合成及在苯乙酮不对称氢转移反应中的应用

设计并合成了一种新型的聚乙二醇单甲醚(MPEG)修饰的温控Noyori配体.将其与[RuCl2.(p-cymene)]2络合形成的催化剂用于水/环己烷两相体系中苯乙酮不对称氢转移反应.以甲酸钠为氢源,考察了反应温度、时间、甲酸钠用量、底物与催化剂摩尔比以及溶剂用量等因素对催化反应的影响.结果表明,反应体系中含催化剂的水相具有浊点,并且催化剂显示出良好的不对称催化性能,在甲酸钠/苯乙酮/催化剂的摩尔比为300:100:1、环己烷/水体积比1:1及30℃的反应条件下反应6h,苯乙酮的转化率为99.7%,产物α-苯乙醇的对映选择性(e.e.)为93.9%.催化剂相易与产物相分离并与直接循环使用,循环使用的催化剂活性明显下降,但产物对映选择性仍保持不变.     

Oxidation of cyclohexane with hydrogen peroxide catalyzed by Dawson-type vanadium-substituted heteropolyacids

Summary A series of Dawson-type vanadium-substituted heteropolyacids were synthesized and used as catalysts for the oxidation of cyclohexane. Their catalytic activities increase with the number of the vanadium atom substituted in the heteropolyacids.     

Liquid extraction of molybdophosphoric and molybdoarsenic acids: application to the determination of phosphorus in the presence of arsenic

The radioisotopes phohphorus-32 and arsenic-74 have been used to study the extraction of molybdophosphoric and molybdoarsenic acids from aqueous solution with various organic solvents. A method is described for the gravivmetric determination of phosphorus in the presence of arsenic which makes use of solvent extraction with n-butyl acetate. The results obtained for the determination of phosphorus in various types of iron and steel are described.     

Amino acids in catalytic synthesis of α-aminophosphonates

The reaction of acetophenone with chiral α-amino acids and their esters has been studied in catalytic one-pot three-component synthesis of α-aminophosphonates. α-Aminophosphonates are found to form mixtures of diastereomers in high yields.