双氰胺对Pd@CN催化剂制备的影响毕业论文
2022-03-05 22:00:38
论文总字数:21422字
摘 要
环己酮在工业、医疗、化妆品等方面有重要的用途。工业上主要的生产方法是环己烷氧化法,苯加氢氧化法和苯酚加氢法。由于环己烷氧化法和苯加氢氧化法的产率低、副产物多,所以苯酚加氢法越来越受到关注。随之而来的便是关于这个反应的催化剂的研究。
Pd能够将氢气充分进行活化,所以载体的选择成为焦点。研究者们指出亲水性载体对苯环的活化具有很大的促进作用,TiO2/C载体便是如此。同时研究者们也认为路易斯酸的存在能够对催化剂的选择性产生很大的影响,氮掺杂的多孔碳(CN)材料的研究也成为热门。而ZIFs材料的出现也显得意义更为重大,ZIFs具有沸石和金属有机骨架的多种特点,是一种能够通过一步热解法生成CN材料的重要前驱体。
本课题以ZIF-67为前驱体,在制备ZIF-67时添加TiO2,煅烧生成TiO2-CN材料,然后负载Pd制备新型的Pd@CN-TiO2催化剂。采用SEM、XRD、XPS等表征手段对制备的材料进行物性表征,并以苯酚加氢生成环己酮为模型反应,考察催化剂的催化性能。结果表明,TiO2的加入对催化性能的提升有一定的效果,在加入量为0.1 g时苯酚转化率为80.9%,环己酮选择性为98.7%。
关键词:环己酮 苯酚加氢 ZIF-67 TiO2 CN
Preparation and Characterization of New Pd@CN Catalyst
Abstract
Cyclohexanone has great use in the industry, medical treatment, cosmetics and so on. The main production methods in the industry are cyclohexane oxidation, benzene hydrogenation and phenol hydrogenation. Cyclohexane oxidation and benzene hydrogenation have draw backs of the low yield and numerous by-products. So phenol hydrogenation gains more and more attention. And the development of catalysts is the focus of study on.
The catalyst with Pd as the active component can fully activate the hydrogen. So the choice of the carrier becomes important. The researchers point out that the hydrophilic carrier has a great effect on the activation of the benzene ring. For instance, the TiO2/C is a nice carrier. At the same time, the researchers also believe that the presence of Lewis acid can have a great impact on the selectivity of the catalyst. Nitrogen-doped carbons (CN) material research has become popular. The appearance of ZIFs is also more significant. ZIFs have many characteristics of zeolite and metal organic skeleton, and it is an important precursor to generate CN material by one-step pyrolysis.
In this paper, ZIF-67 was used as the precursor. TiO2 was added by the preparation of ZIF-67, which was calcined to form TiO2-CN material, and Pd@CN-TiO2 catalyst was prepared by the addition of Pd. The properties of the prepared materials were characterized by SEM, XRD and XPS. The catalytic performance of the catalysts was investigated by hydrogenation of phenol to cyclohexanone. The results showed that the addition of TiO2 had some effect on the catalytic performance. The conversion of phenol was 80.9% and the selectivity of cyclohexanone was 98.7% with the addition of TiO2 of 0,1 g.
Key Words: Cyclohexanone; Phenol hydrogenation; ZIF-67; TiO2; N-doped carbons
目 录
摘 要 I
Abstract III
第一章 文献综述 1
1.1 环己酮的性质及生产工艺 1
1.1.1 环己烷氧化法 1
1.1.2 苯加氢氧化法 1
1.1.3 苯酚加氢法 1
1.2 苯酚加氢法的催化剂 2
1.2.1 Pd/C-TiO2催化剂 2
1.2.2 Pd@mpg-C3H4催化剂 3
1.3 CN材料的制备 4
1.3.1 软模板法 4
1.3.2 硬模板法 5
1.4 金属有机骨架(MOFs) 5
1.5 类沸石咪唑脂骨架(ZIFs) 6
1.5.1 ZIFs材料的制备 6
1.5.2 ZIFs材料制备多孔碳 6
1.6 本文的研究目的与内容 7
第二章 实验部分 8
2.1 实验原料及设备 8
2.2 催化剂的制备及催化性能测试 9
2.2.1 TiO2-ZIF-67的制备 9
2.2.2 TiO2-ZIF-67的煅烧及酸洗 9
2.2.3 Pd@CN-TiO2催化剂的制备 9
2.2.4 Pd@CN-TiO2的催化性能测试过程 10
2.3 表征仪器 10
2.3.1 X-射线衍射(XRD) 10
2.3.2 电镜表征(FESEM) 10
2.3.3 N2吸附-脱附 11
2.3.4 热重分析(TG) 11
2.3.5 X-射线电子能谱仪(XPS) 11
第三章 结果与讨论 12
3.1 物相表征 12
3.1.1 TiO2-ZIF-67的表征 12
3.1.2 TiO2-Co/CN的表征 14
3.1.3 TiO2-CN材料的表征 15
3.1.4 Pd@CN-TiO2催化剂的表征 19
3.2 催化剂的催化性能 19
第四章 结论与展望 21
4.1 结论 21
4.2 展望 21
参考文献 22
致谢 24
第一章 文献综述
1.1 环己酮的性质及生产工艺
环己酮(C6H10)是一种无色透明的,带有泥土气息的液体,微溶于水,有麻醉作用,同时也是易燃易爆的液体。
环己酮是一些化工原料的重要中间体,由于其较难挥发常被用来作为有机溶剂,同时在制药方面也有重大作用,并且在化妆品方面也有很大的应用。在我国,环己酮的应用已经非常广泛,给国家和企业带来了较大的经济效益,具有非常好的市场潜力[1]。
请支付后下载全文,论文总字数:21422字