稀土固体超强酸催化剂SO42-/TiO2/Ce4+的制备及其性能研究

采用X射线衍射(XRD),BET吸附,红外光谱(IR),差示扫描量热分析(DSC)表征了溶胶-凝胶法制备的稀土固体超强酸催化剂SO42-/TiO2/Ce4 的晶体结构、比表面积和表面结构.并以催化苯甲醛与乙二醇的缩合反应为指针,测试Ce掺杂对催化剂催化活性的影响.结果表明,掺杂Ce4 可以阻碍TiO2的晶型转变,减小催化剂的晶粒尺寸,比表面积增大.同时Ce4 的掺杂增强了催化剂Lewis酸性和提高催化剂表面与活性物种SO42-的配位能力从而增加催化剂表面活性中心的数目,这是提高催化剂活性的主要原因之一.掺杂Ce4 的摩尔分数x(Ce4 )=1.2%、焙烧温度为550℃时催化剂活性最高,此时催化剂为锐钛矿型.     

Acidic catalysis of microporous polyoxometalate H3PW12O40/Sio2 in acetal reaction between benzaldehyde and ethylene glycol

Microporous Keggin-type polyoxometalate material was synthesised by supporting H3PW12O40 into a silica matrix via a sol-gel technique. The silica-supported 12-tungstophosphoric acid ( H₃PW₁₂O₄₀/Sio₂ ) obtained is insoluble and readily separable porous materials with uniform micropores (0. 57 nm) and a high specific surface area (350. 5 m2/g) in oxygen-containing polar solvents. H3PW12 O4o/Si02 was characterized by infrared spectrophotometer (IR). ultraviolet-visible spectrophotometer (UV-vis). inductively coupled plasma (ICP)> thermogravimetric analysis (TGA) and Brunner-Emmett-Teller method (BET) measurements. H3PWi204o/Si02 obtained catalyzed the acetal reaction between benzaldehyde and ethylene glycol to produce 2-phenyl-l > 3-dioxolane more efficiently than the typical solid acids such as SO4 /ZrO2' Nafion-H and H-ZSM-5. Conversion was 93. 8% for benzaldehyde during the reaction period of 2 h. H₃PW₁₂O₄₀/Sio₂ kept its initial activity during three times of reuse. The initial acetal reaction follows a second-order kinetics model at 298 K.     

化学复合山梨醇缩醛类成核剂的合成、结构表征及在聚丙烯中的应用

以对甲基苯磺酸为催化剂,对甲基苯甲醛与对氯苯甲醛组成的混合醛和山梨醇为原料,合成了化学复合山梨醇缩醛类成核剂。在混合醛/山梨醇(摩尔比)2.05:1的条件下,分别合成了对氯苯甲醛与对甲基苯甲醛之比为1:0(E1)、4:1(E2)、3:1(E3)、2:1(E4)、1:1(E5)、1:3(E6)、1:4(E7)和0:1(E8)的复合成核剂,利用傅里叶红外光谱(FTIR)和X射线衍射(XRD),分别表征了成核剂的晶体结构和分子结构,FTIR测试显示合成的产物为山梨醇缩醛;XRD测试表明,采用复合醛合成的复合缩醛的晶体结构与E1不同。熔点测试发现,化学复合成核剂的熔点随原料中对甲基苯甲醛与对氯苯甲醛的摩尔比的增大而逐步提高。对聚丙烯的成核改性实验表明,化学复合成核剂具有增透和增刚的双重功能。     

不同催化剂催化合成缩醛（缩酮）

本文分别用对甲苯磺酸，无水三氯化铝，分子筛，氧化铝和蒙脱土催化乙二醇与醛或酮生成铜醛（酮）的缩会反应.     

4-二甲胺基丁醛二乙基缩醛的合成

4-二甲胺基丁醛二乙基缩醛是制备治疗偏头痛的曲坦类药物的关键中间体,其合成工艺的优劣对药物的合成成本有重要影响。本文以1-溴-3-氯丙烷为起始原料,与二甲胺水溶液经相转移催化剂聚乙二醇催化得到3-二甲胺基-1-氯丙烷,然后于2-甲基四氢呋喃中与镁反应制得格氏试剂,而后与原甲酸三乙酯反应得到目标化合物。该路线总收率70.11%,路线简单、污染低、易操作、收率高。     

Acidic catalysis of microporous polyoxometalate H3PW12O40/SiO2 in acetal reaction between benzaldehyde and ethylene glycol

Microporous Keggin-type polyoxometalate material was synthesised by supporting H3PW12O40 into a silica matrix via a sol-gel technique. The silica-supported 12-tungstophosphoric acid (H3PW12O4o/SiO2) obtained is insoluble and readily separable porous materials with uniform micropores (0.57 nm) and a high specific surface area (350.5 m2/g) in oxygen-containing polar solvents. H3PW12 O40/SiO2 was characterized by infrared spectrophotometer (IR), ultraviolet-visible spectrophotometer (UV-vis), inductively coupled plasma (ICP), thermogravimetric analysis (TGA) and Brunner-Emmett-Teller method (BET) measurements. H3PW12O40/SiO2 obtained catalyzed the acetal reaction between benzaldehyde and ethylene glycol to produce 2-phenyl-1, 3-dioxolane more efficiently than the typical solid acids such as SO2-4/ZrO2, Nafion-H and H-ZSM-5. Conversion was 93.8 % for benzaldehyde during the reaction period of 2 h.H3PW12O40/SiO2 kept its initial activity during three times of reuse. The initial acetal reaction follows a second-order kinetics model at 298 K.     

渗透蒸发膜的研制：聚丙烯酸与聚乙烯醇等共混及其缩醛化

以乙醇水溶液为分离对象，研究了聚丙烯酸（ＰＡＡ）与聚酰胺羧或聚乙烯醇（ＰＶＡ）共混膜的渗透蒸发分离性能，以及均相，非均相缩醛反应对ＰＶＡ膜分离因素α和渗透通量Ｊ的影响。实验发现，戊二醛交联ＰＶＡ膜的α提高 到４９．５（乙醇含水Ｃ１＝１０％，温度为５５℃）；增加非均相缩甲醛反应时间，ＰＶＡ／ＰＡＡ共混膜的α先下降而后趋于不变，同时Ｊ存在一最大值。     

固体酸催化剂在缩醛(酮)合成中的应用

综述了硅铝酸盐类、固体超强酸、离子交换树脂、杂多酸以及无机氯化物和硫酸盐等五类固体酸催化剂在催化合成缩醛 (酮 )中的应用和研究进展。通过活性比较发现硅铝酸盐类通过增大骨架硅铝比 ,可增强酸中心强度 ,使缩醛(酮 )反应更顺利进行 ;无机盐的酸中心强度与电负性与离子半径之比的大小成一致关系 ,且酸强度越大 ,缩醛 (酮 )的催化合成越容易进行。     

磷钨酸/硅胶催化剂催化合成丁醛1,2-丙二醇缩醛

以溶胶-凝胶法自制的磷钨酸/硅胶为催化剂,通过丁醛和1,2-丙二醇为原料反应合成丁醛1,2-丙二醇缩醛,探讨了磷钨酸/硅胶催化剂对缩醛反应的催化活性,用正交试验法较系统地研究了醛醇量比、催化剂用量、带水剂用量、反应时间诸因素对产品收率的影响.实验表明:磷钨酸/硅胶是合成丁醛1,2-丙二醇缩醛的良好催化剂,在n(丁醛):...