载体改性对乙炔氢氯化反应钌基催化剂性能的影响
发布时间：2019-03-21 09:21
【摘要】：聚氯乙烯(PVC)树脂是世界五大工程塑料之一,在各行各业有着非常广泛的应用。目前氯乙烯单体的工业合成方法主要有乙烯法和乙炔法。发达国家多采用石油化工资源的乙烯法,但因为我国特殊的“富煤、贫油、少气”的能源结构和乙烯原料匮乏,决定了占据我国合成氯乙烯工艺路线主导地位的是乙炔氢氯化法。在电石法氯乙烯生产中,氯化汞催化剂由于其催化活性与选择性都比较理想而成为广泛应用的催化剂。但是,氯化汞催化剂的升华、流失为人类和环境所带来的毒性与污染成为长期困扰电石法PVC工艺路线的问题。为实现电石法PVC工艺路线的可持续发展,必须开发环境友好的、高性能的、能替代汞系催化剂的新型无汞催化剂。本文主要从载体改性对乙炔氢氯化反应中Ru基催化剂活性组分和Ru颗粒大小的影响方面来探讨。主要研究内容为以下三个方面:(1)合成3D复合碳氮材料(g-C_3N_4 NS-CNT)载体负载RuCl3制备Ru/g-C_3N_4 NS-CNT催化剂,N2-吸附脱附曲线(BET)表明了g-C_3N_4 NS-CNT材料的多孔结构,这可以提供大量的活性位,X射线衍射(XRD)说明g-C_3N_4 NSs和CNTs的特征峰被完好保存在3D g-C_3N_4 NS-CNT复合材料中,XPS证明了它们之间的强耦合作用。活性测试可知,复合材料载体负载的Ru基催化剂的催化活性有一定程度的提高。(2)对活性炭表面进行一步和两步液相氧化法的改性,用沉淀-浸渍法和还原法制备Ru基催化剂。由活性测试可知,两步液相法制备的Ru基催化剂的初始活性要比一步法的高,由TEM和CO-TPD表征解释原因为,用两步氧化法处理后的载体会使Ru基催化剂产生更小粒径的均一Ru颗粒。(3)对活性炭(AC)表面进行-NO2,-NH2和-NHN氮官能团的改性,以AC和改性后的活性炭为载体,RuCl3为活性组分,通过等体积浸渍法制备Ru基催化剂。用傅立叶红外光谱(FT-IR)、N2-吸附脱附曲线(BET)和元素分析来验证氮官能团的引入,用X射线光电子能谱分析(XPS)和分峰软件来说明不同Ru物种的变化,用程序升温脱附(TPD)来观察对HCl和C2H3Cl的吸附情况。经过活性测试可知,改性载体负载的Ru基催化剂相对于未改性负载的催化剂,活性有大幅度提高,主要的原因归于RuO2活性组分的增加和HCl吸附的增强。
[Abstract]:PVC (polyvinyl chloride) resin is one of the five major engineering plastics in the world, and has a very wide application in all walks of life. At present, the industrial synthesis of vinyl chloride monomer is mainly ethylene and acetylene. In the developed countries, the ethylene method of petrochemical resources is used, but because of the energy structure and the shortage of the ethylene raw materials of the special "rich coal, lean oil and less gas" in China, the acetylene hydrochlorination process is determined to occupy the leading role of the synthetic vinyl chloride process in China. In that production of chloroethylene by the calcium carbide method, the mercuric chloride catalyst is a widely used catalyst because of the ideal catalytic activity and selectivity. However, the sublimation of the mercuric chloride catalyst and the loss of the toxicity and the pollution caused by the human and the environment have become a long-term problem of the process route of the calcium carbide method PVC. In order to realize the sustainable development of the PVC process route of the calcium carbide method, an environment-friendly, high-performance, mercury-free catalyst capable of replacing the mercury-based catalyst must be developed. In this paper, the effect of carrier modification on the active component of Ru-based catalyst and the size of Ru particles in the chlorination of acetylene is discussed. The main contents of the study are as follows: (1) The preparation of Ru/ g-C _ 3N _ 4NS-CNT catalyst by synthesis of a 3D composite carbon-nitrogen material (g-C _ 3N _ 4NS-CNT) carrier and the N2-adsorption desorption curve (BET) show the porous structure of the g-C _ 3N _ 4NS-CNT material, which can provide a large number of active sites, X-ray diffraction (XRD) shows that the characteristic peaks of g-C _ 3N _ 4 NSs and CNTs are well preserved in the 3D-g-C _ 3N _ 4NS-CNT composite, and the XPS shows the strong coupling between them. The activity test shows that the catalytic activity of the Ru-based catalyst supported by the composite carrier is improved to some extent. (2) the surface of the activated carbon is modified by one-step and two-step liquid-phase oxidation, and the Ru-based catalyst is prepared by a precipitation-impregnation method and a reduction method. As can be seen from the activity test, the initial activity of the Ru-based catalyst prepared by the two-step liquid phase method is higher than that of the one-step method, and the reason of the explanation by the TEM and the CO-TPD is that the Ru-based catalyst can generate uniform Ru particles with smaller particle size by the Ru-based catalyst after the two-step oxidation process is used. And (3) modifying the surface of the active carbon (AC)-NO2,-NH2 and-NHN nitrogen, taking AC and modified active carbon as a carrier, and RuCl3 as an active component, and preparing a Ru-based catalyst by equal volume impregnation. The introduction of nitrogen functional groups was verified by FT-IR, N2-adsorption and desorption curves (BET) and elemental analysis, and the changes of different Ru species were described by X-ray photoelectron spectroscopy (XPS) and peak-splitting software. The adsorption of HCl and C2H3Cl was observed by temperature-programmed desorption (TPD). The activity test shows that the activity of the supported Ru-based catalyst is greatly improved compared with the non-modified supported catalyst, and the main reason is attributed to the increase of the RuO2 active component and the enhancement of the adsorption of HCl.
【学位授予单位】：石河子大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：O643.36;TQ222.423
，
本文编号：2444802
[Abstract]:PVC (polyvinyl chloride) resin is one of the five major engineering plastics in the world, and has a very wide application in all walks of life. At present, the industrial synthesis of vinyl chloride monomer is mainly ethylene and acetylene. In the developed countries, the ethylene method of petrochemical resources is used, but because of the energy structure and the shortage of the ethylene raw materials of the special "rich coal, lean oil and less gas" in China, the acetylene hydrochlorination process is determined to occupy the leading role of the synthetic vinyl chloride process in China. In that production of chloroethylene by the calcium carbide method, the mercuric chloride catalyst is a widely used catalyst because of the ideal catalytic activity and selectivity. However, the sublimation of the mercuric chloride catalyst and the loss of the toxicity and the pollution caused by the human and the environment have become a long-term problem of the process route of the calcium carbide method PVC. In order to realize the sustainable development of the PVC process route of the calcium carbide method, an environment-friendly, high-performance, mercury-free catalyst capable of replacing the mercury-based catalyst must be developed. In this paper, the effect of carrier modification on the active component of Ru-based catalyst and the size of Ru particles in the chlorination of acetylene is discussed. The main contents of the study are as follows: (1) The preparation of Ru/ g-C _ 3N _ 4NS-CNT catalyst by synthesis of a 3D composite carbon-nitrogen material (g-C _ 3N _ 4NS-CNT) carrier and the N2-adsorption desorption curve (BET) show the porous structure of the g-C _ 3N _ 4NS-CNT material, which can provide a large number of active sites, X-ray diffraction (XRD) shows that the characteristic peaks of g-C _ 3N _ 4 NSs and CNTs are well preserved in the 3D-g-C _ 3N _ 4NS-CNT composite, and the XPS shows the strong coupling between them. The activity test shows that the catalytic activity of the Ru-based catalyst supported by the composite carrier is improved to some extent. (2) the surface of the activated carbon is modified by one-step and two-step liquid-phase oxidation, and the Ru-based catalyst is prepared by a precipitation-impregnation method and a reduction method. As can be seen from the activity test, the initial activity of the Ru-based catalyst prepared by the two-step liquid phase method is higher than that of the one-step method, and the reason of the explanation by the TEM and the CO-TPD is that the Ru-based catalyst can generate uniform Ru particles with smaller particle size by the Ru-based catalyst after the two-step oxidation process is used. And (3) modifying the surface of the active carbon (AC)-NO2,-NH2 and-NHN nitrogen, taking AC and modified active carbon as a carrier, and RuCl3 as an active component, and preparing a Ru-based catalyst by equal volume impregnation. The introduction of nitrogen functional groups was verified by FT-IR, N2-adsorption and desorption curves (BET) and elemental analysis, and the changes of different Ru species were described by X-ray photoelectron spectroscopy (XPS) and peak-splitting software. The adsorption of HCl and C2H3Cl was observed by temperature-programmed desorption (TPD). The activity test shows that the activity of the supported Ru-based catalyst is greatly improved compared with the non-modified supported catalyst, and the main reason is attributed to the increase of the RuO2 active component and the enhancement of the adsorption of HCl.
【学位授予单位】：石河子大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：O643.36;TQ222.423
，
本文编号：2444802
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