共查询到20条相似文献,搜索用时 15 毫秒
1.
以植酸钙(PA-Ca)为载体、H2Pd Cl4为前驱体、甲醇为还原剂,制备了PA-Ca负载Pd的Pd/PA-Ca催化剂,对其进行XRF、BET、SEM、TEM、XRD和XPS表征,并用于苯甲醛氧化制备苯甲酸反应,考察催化剂用量、反应温度和溶剂种类对催化剂催化性能的影响。结果表明,催化剂中负载Pd质量分数为1.03%,钠质量分数为1.05%;合成的PA-Ca载体为晶化程度较低的介孔材料,比表面积为18.85 m~2·g~(-1);催化剂活性物种为Pd0和PdO。在催化剂用量n(苯甲醛)∶n(Pd)=2 000∶1、乙腈作溶剂、O_2压力101.325 k Pa(流速20 m L·min~(-1))、反应温度30℃和反应时间4 h条件下,苯甲醛转化率为83%,苯甲酸选择性为100%;催化剂具有较好的稳定性,可循环使用3~4次。 相似文献
2.
3.
4.
铝柱撑活性白土催化合成苯甲醛乙二醇缩醛 总被引:1,自引:0,他引:1
以活性白土为原料,经过铝交联剂改性制成铝柱撑活性白土,并以此为催化剂,用于苯甲醛与乙二醇反应合成苯甲醛乙二醇缩醛。结果表明:铝柱撑活性白土是合成苯甲醛乙二醇缩醛的良好催化剂。最佳反应条件为:n(苯甲醛)∶n(乙二醇)为1∶1.8,催化剂1.2 g,带水剂甲苯15 mL,160℃搅拌回流3.5 h,收率可达86.8%。同时也考察了三种方法制备的铝柱撑活性白土对产品收率的影响,上述条件下用微波作用制备的铝柱撑活性白土催化效果最好,产品收率可达88.7%。 相似文献
5.
6.
7.
以碘(I2)掺杂聚苯胺(PAn)为催化剂,采用正交试验法,通过苯甲醛和乙二醇反应合成了苯甲醛乙二醇缩醛。考察了醛醇物质的量比、催化剂用量及反应时间诸因素对产品收率的影响。实验结果表明,在n(苯甲醛):n(乙二醇)=1:1.5,I2/PAn催化剂用量占反应物料总质量的0.60%,带水剂为环己烷,反应时间为1.0h条件下,苯甲醛乙二醇缩醛收率可达85.3%。 相似文献
8.
以SO42-/γ-Al2O3为催化剂,以苯甲醛和乙二醇为原料进行缩合反应合成了苯甲醛缩乙二醇。考察了催化剂的制备条件如硫酸浸渍浓度、焙烧温度对催化活性的影响;同时也考察了反应条件如反应物摩尔比、催化剂用量、反应时间对苯甲醛转化率的影响。结果表明,SO42-/γ-Al2O3是合成苯甲醛缩乙二醇的良好催化剂。催化剂的最佳制备条件为:硫酸浸渍浓度2.5 mol.L-1,焙烧温度650℃;最佳反应条件为:苯甲醛0.05 mol,n(苯甲醛)∶n(乙二醇)=1∶2,催化剂1.0 g,带水剂环己烷5 mL,100℃回流反应120 min。此时苯甲醛转化率可达96.51%。催化剂可回收利用,回收效率取决于焙烧温度。 相似文献
9.
以邻苯二胺和苯甲醛为原料合成了苯并咪唑。考察了催化剂类型及用量、溶剂类型、反应温度、反应时间对目标产物苯并咪唑产率的影响。确定适宜的反应条件如下:邻苯二胺与苯甲醛物质的量比为2.5∶1、以偏钒酸铵为催化剂、m(偏钒酸铵)∶m(苯甲醛)为0.19∶1、以三氯甲烷为溶剂、反应温度为50℃、反应时间为4h,在此条件下,苯并咪唑产率高达81.3%。 相似文献
10.
11.
采用绿色环保的盐酸硫胺(VB1)催化苯甲醛和乙二醇缩醛反应,系统考察了醇醛物质量比、催化剂用量以及反应时间对产品收率的影响。最佳的工艺条件为苯甲醛和乙二醇物质的量比为1∶1.8(摩尔比)、催化剂用量为反应物料总质量的0.2%、带水剂环己烷10 mL、反应时间为1.0 h。在此反应条件下,苯甲醛乙二醇缩醛的收率可达87.2%。 相似文献
12.
13.
14.
Wei Long Zhilong Chen Yinfei Huang Xinping Kang 《International journal of molecular sciences》2022,23(21)
Nanometer-size Co-ZIF (zeolitic imidazolate frameworks) catalyst was prepared for selective oxidation of toluene to benzaldehyde under mild conditions. The typical characteristics of the metal-organic frameworks (MOFs) material were affirmed by the XRD, SEM, and TEM, the BET surface area of this catalyst was as high as 924.25 m2/g, and the diameter of particles was near 200 nm from TEM results. The Co metal was coated with 2-methyl glyoxaline, and the crystalline planes were relatively stable. The reaction temperatures, oxygen pressure, mass amount of N-hydroxyphthalimide (NHPI), and reaction time were discussed. The Co-ZIF catalyst gave the best result of 92.30% toluene conversion and 91.31% selectivity to benzaldehyde under 0.12 MPa and 313 K. The addition of a certain amount of NHPI and the smooth oxidate capacity of the catalyst were important factors in the high yield of benzaldehyde. This nanometer-size catalyst showed superior performance for recycling use in the oxidation of toluene. Finally, a possible reaction mechanism was proposed. This new nanometer-size Co-ZIF catalyst will be applied well in the selective oxidation of toluene to benzaldehyde. 相似文献
15.
苯甲醛甘油缩醛绿色催化合成工艺研究 总被引:3,自引:0,他引:3
以苯甲醛和甘油为原料,通过活性炭负载磷钨酸(TPA)为催化剂,催化合成苯甲醛甘油缩醛。分别研究了催化剂磷钨酸负载量、反应时间、反应物配比及催化剂用量对合成反应的影响。结果表明,TPA负载量(质量分数)15%,催化剂用量(质量分数)4%,苯甲醛:甘油=1:1.1(摩尔比),反应时间2.0h,苯甲醛甘油缩醛的收率可达96.4%。 相似文献
16.
17.
Polyurea microcapsules containing NiCl2 were prepared by interracial polymerization between diisocyanate and water with triethylamine as a catalyst in water-in-oil emulsion system. The influence of preparation conditions such as the dosage and feed mode of the catalyst, concentration of the encapsulated NiCl2, and concentration and structure of diisocyanates on the breakage of the microcapsules have been evaluated. The results show thatbreakage is strongly dependent on the rate of polymerization and stability of initial emulsion. The improved microcapsules with low breakage have been produced under the optimum conditions. Furthermore, the obtained microcapsules capsules immobilizing NiCl2 as a recyclable catalyst is successfully used in benzaldehyde reduction. 相似文献
18.
19.