發(fā)布時(shí)間：2019-04-28 16:19

【摘要】：四價(jià)氧化物納米材料是一種新型的無機(jī)功能材料,由于其自身獨(dú)特的物化性能而被廣泛的用作催化劑載體或者直接作為催化劑使用,廣泛應(yīng)用于氧化、光催化、催化加氫等各個(gè)催化領(lǐng)域當(dāng)中。其中具有代表性的氧化物納米材料,例如：二氧化鈦、二氧化鈰、二氧化鋯等。催化加氫反應(yīng)作為催化科學(xué)研究領(lǐng)域當(dāng)中的核心問題之一,是催化反應(yīng)當(dāng)中的基礎(chǔ)反應(yīng),在實(shí)際中應(yīng)用非常普遍廣泛。葡萄糖加氫制得山梨醇是工業(yè)上主要制備山梨醇的方法,山梨醇是一種應(yīng)用很廣泛的精細(xì)化工產(chǎn)品和工業(yè)原料。山梨醇具有無氣味、有甜味、無毒性、保濕性、乳化性等優(yōu)異的性能,是一種非常重要的高附加值的精細(xì)化工產(chǎn)品。山梨醇及其產(chǎn)物普遍應(yīng)用在化妝品、食品添加劑、煙草、化工、制藥等行業(yè)當(dāng)中。α,p-不飽和醛酮因其結(jié)構(gòu)特殊而具有非常高的生化活性,其加氫產(chǎn)物種類繁多,在現(xiàn)代化工領(lǐng)域中占據(jù)極其重要的位置。其中肉桂醛和檸檬醛都是α,p-不飽和醛酮的代表。肉桂醛和檸檬醛大部分加氫產(chǎn)物廣泛應(yīng)用于香精、香料、醫(yī)藥等領(lǐng)域,因而研究其催化加氫反應(yīng)對生產(chǎn)生活、科學(xué)理論研究都具有非常重要的現(xiàn)實(shí)意義。本文中分別以單金屬氧化物和雙金屬氧化物為載體,以Ru、Pt金屬為活性組分得到了負(fù)載型催化劑,并研究其在各反應(yīng)當(dāng)中的催化加氫性能。詳細(xì)內(nèi)容如下：(1)制備Ru/TiO2催化劑和其催化性能評價(jià)。用硼氫化鈉作為沉淀劑,以四氯化鈦?zhàn)鳛樵现苽涑龆趸佪d體。合成出了高比表面的納米材料,其比表面高達(dá)215.8m2 g-1。再將硼氫化鈉作為還原劑,制備出高分散的負(fù)載型釕催化劑Ru/TiO2,其中釕的負(fù)載量為3%wt,并將其應(yīng)用到葡萄糖的催化加氫反應(yīng)當(dāng)中,與傳統(tǒng)載體負(fù)載的催化劑相比催化性能結(jié)果明顯提高。(2)制備高比表面、高分散的負(fù)載型Pt/CeO2-ZrO2催化劑。采用成核／晶化隔離法與熱動(dòng)力學(xué)可控的水熱法相結(jié)合的新的合成方法,以硼氫化鈉為沉淀劑,不需要經(jīng)過高溫煅燒,直接一步合成了所需的四價(jià)雙金屬復(fù)合氧化物。并采用液相還原的方法,進(jìn)一步制備高分散的負(fù)載型鉑催化劑Pt/CeO2-ZrO2,其中鉑的負(fù)載量為5%wt,并評價(jià)其對肉桂醛的加氫性能。其催化活性明顯高于單載體負(fù)載的Pt/CeO2或Pt/ZrO2。通過改變鈰鋯的比例,制備不同載體的Pt/CeO2-ZrO2催化劑,載體中的CeO2-ZrO2與鉑存強(qiáng)相互作用,金屬分散性提高,同時(shí)催化劑表面的酸性位的數(shù)量及酸強(qiáng)度和pt0的富電子性也明顯提高,在肉桂醛催化加氫反應(yīng)中顯示出更高的活性和對C=O鍵的選擇性。
[Abstract]:Tetravalent oxide nanomaterials are new inorganic functional materials. Because of their unique physical and chemical properties, tetravalent oxide nanomaterials are widely used as catalyst carriers or directly used as catalysts, and are widely used in oxidation and photocatalysis. Catalytic hydrogenation and other catalytic fields. Representative oxide nanomaterials, such as titanium dioxide, cerium dioxide, zirconia and so on. Catalytic hydrogenation, as one of the core issues in the field of catalytic science, is the basic reaction in catalytic reaction, and it is widely used in practice. The preparation of sorbitol from glucose hydrogenation is the main method to prepare sorbitol in industry. Sorbitol is a widely used fine chemical product and industrial raw material. Sorbitol has excellent properties, such as odorless, sweet, non-toxic, hygroscopic, emulsifying and so on. It is a very important fine chemical product with high added value. Sorbitol and its products are widely used in cosmetics, food additives, tobacco, chemical industry, pharmaceutical and other industries. 偽, p-unsaturated aldehydes and ketones have very high biochemical activity because of their special structure. It occupies a very important position in the field of modern chemical industry. Cinnamaldehyde and citral are the representatives of 偽, p-unsaturated aldehydes and ketones. Most of the hydrogenation products of cinnamaldehyde and citral are widely used in the fields of essence, spice, medicine and so on. Therefore, the study of catalytic hydrogenation of cinnamaldehyde and citral has very important practical significance for production and life, scientific and theoretical research. In this paper, the supported catalysts were prepared by using single metal oxide and bimetallic oxide as support and Ru,Pt metal as active component, respectively, and their catalytic hydrogenation performance in each reaction was studied. The main contents are as follows: (1) preparation of Ru/TiO2 catalyst and evaluation of its catalytic performance. Titanium dioxide carrier was prepared by using sodium borohydride as precipitator and titanium tetrachloride as raw material. Nano-materials with high specific surface area have been synthesized. The specific surface area is as high as 215.8m2 g _ 1. Then, sodium borohydride was used as reducing agent to prepare highly dispersed supported ruthenium catalyst Ru/TiO2, in which the amount of ruthenium supported was 3% wt, and it was applied to the catalytic hydrogenation of glucose. Compared with the catalyst supported on the traditional support, the catalytic performance of the catalyst was improved obviously. (2) the supported Pt/CeO2-ZrO2 catalyst with high specific surface area and high dispersion was prepared. A new synthesis method combining nucleation / crystallization isolation method with thermodynamic controllable hydrothermal method was adopted. The tetravalent bimetallic composite oxide was synthesized directly in one step using sodium borohydride as precipitant and without the need of high temperature calcination. The highly dispersed supported platinum catalyst Pt/CeO2-ZrO2, was further prepared by liquid phase reduction, in which the platinum loading was 5% w / t, and the hydrogenation performance of the catalyst to cinnamaldehyde was evaluated. Its catalytic activity is obviously higher than that of Pt/CeO2 or Pt/ZrO2. supported on single carrier. Pt/CeO2-ZrO2 catalysts with different supports were prepared by changing the ratio of cerium to zirconium. CeO2-ZrO2 in the support interacted with platinum and the metal dispersion was improved. At the same time, the number of acidic sites on the surface of the catalyst and the strength of acid and the electron-rich property of pt0 were also improved obviously. The catalytic hydrogenation of cinnamaldehyde showed higher activity and selectivity for C _ (O) bond.
【學(xué)位授予單位】：北京化工大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2016
【分類號(hào)】：O643.36

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