本文選題：甘油 + 氫解��； 參考：《東南大學(xué)》2017年碩士論文

【摘要】：隨著當(dāng)今社會(huì)的飛速發(fā)展,能源危機(jī)成為當(dāng)今世界面臨的重大問題之一。因此,可循環(huán)使用的材料受到了人們?cè)絹碓蕉嗟年P(guān)注。生物柴油生產(chǎn)過程中的主要副產(chǎn)物甘油,被認(rèn)為是替代石油和天然氣來生產(chǎn)許多重要化學(xué)工業(yè)產(chǎn)品的最可行、最有前途的一種原材料。由于甘油生產(chǎn)的大量過剩以及丙二醇在工業(yè)上的廣泛應(yīng)用,甘油氫解制備1,2-丙二醇和1,3-丙二醇有著重要的科研和商業(yè)上的意義。根據(jù)文獻(xiàn)研究,銅基催化劑對(duì)C-C鍵的斷裂能力有限,銅基催化劑對(duì)甘油氫解有著較高的轉(zhuǎn)化率,對(duì)丙二醇有著較高的選擇性。但是Cu基催化劑對(duì)于甘油氫解制備丙二醇的效果仍然不夠理想,因此通過添加其它成分對(duì)銅基催化劑進(jìn)行改性,進(jìn)一步提高催化劑的活性是當(dāng)今研究的熱點(diǎn)之一。本論文通過浸漬法制備了一系列負(fù)載型銀銅雙金屬催化劑,并應(yīng)用于甘油氫解制丙二醇反應(yīng)。制得的催化劑采用H2程序升溫還原、NH3程序升溫脫附、X射線衍射、N2吸脫附、N2O化學(xué)吸附、熱重分析、電感耦合等離子光譜、掃描電鏡以及X射線光電子能譜分析等方法進(jìn)行表征。實(shí)驗(yàn)結(jié)果表明,5wt.%銀加入到銅基催化劑中,有利于催化劑的還原,提高了催化劑的表面酸性和催化劑中銅顆粒的分布,進(jìn)而提高了甘油的轉(zhuǎn)化率和丙二醇的產(chǎn)率。當(dāng)5wt.%銀和15wt.%銅同時(shí)負(fù)載在氧化鋁載體表面時(shí),催化劑的酸性更高,分散性更好,銅的表面積更大,因而催化劑的催化效果更佳。另外,文章還詳細(xì)地研究了金屬含量比例、金屬浸漬順序、反應(yīng)溫度、反應(yīng)壓力、反應(yīng)時(shí)間、反應(yīng)溶劑和溶劑酸堿性對(duì)反應(yīng)影響以及催化劑的重復(fù)使用性。當(dāng)優(yōu)選的5Ag-15Cu/A1203催化劑在22C℃、3.5 MPa的優(yōu)選條件下反應(yīng)8 h時(shí),催化劑對(duì)甘油的轉(zhuǎn)化率為66.5%,對(duì)1,2-丙二醇的選擇性為68.2%,對(duì)1,3-丙二醇的選擇性為3.1%。為了進(jìn)一步提高銀銅催化劑對(duì)1,3-丙二醇的選擇性,本論文通過浸漬法制備了不同含量雜多酸和不同種類雜多酸改性的銀銅催化劑應(yīng)用于甘油氫解反應(yīng)并通過吡啶紅外、拉曼衍射等技術(shù)進(jìn)行表征分析。反應(yīng)結(jié)果和表征結(jié)果表明,雜多酸的加入能進(jìn)一步地促進(jìn)催化劑的還原,提高催化劑的分散性,增強(qiáng)催化劑的表面酸性和B酸酸量,進(jìn)而提高催化劑對(duì)1,3-丙二醇的選擇性。與磷鎢酸和磷鉬酸改性的催化劑相比,硅鎢酸改性的銀銅催化劑的銅分散性更好,表面的B酸酸量更多,對(duì)1,3-丙二醇的選擇性更高。當(dāng)10wt.%硅鎢酸改性的5Agl5Cu/A1203催化劑在220℃、3.5 MPa的最佳反應(yīng)條件下,在200 mL高壓釜中反應(yīng)8 h,催化劑對(duì)甘油的轉(zhuǎn)化率為69.6%,對(duì)1,2-丙二醇的選擇性為35.6%,對(duì)1,3-丙二醇的選擇性達(dá)21.5%。而且硅鎢酸改性后的催化劑的重復(fù)性有了明顯的提高。
[Abstract]:With the rapid development of today's society, the energy crisis has become one of the major problems facing the world. Therefore, people pay more and more attention to recyclable materials. Glycerol, the main by-product of biodiesel production, is considered to be the most feasible and promising raw material instead of oil and natural gas to produce many important chemical industrial products. Due to the excessive production of glycerol and the wide application of propanediol in industry, it is of great scientific and commercial significance to produce 1o 2-propanediol and 1o 3-propanediol by hydrogenolysis of glycerol. According to the literatures, the cleavage ability of the copper-base catalyst to C-C bond is limited, the copper-based catalyst has higher conversion to hydrogenolysis of glycerol and higher selectivity to propylene glycol. However, the effect of Cu-based catalyst on hydrogenolysis of glycerol to propanediol is still not ideal. Therefore, it is one of the hot research topics to further improve the activity of Cu-based catalyst by adding other components to modify the catalyst. In this paper, a series of supported silver and copper bimetallic catalysts were prepared by impregnation method and were used in the hydrogenolysis of glycerol to propylene glycol. The catalyst was characterized by H _ 2 temperature-programmed reduction (H _ 2) temperature programmed desorption of NH _ 3 and X-ray diffraction (XRD) N _ 2 adsorption, thermogravimetric analysis, inductively coupled plasma spectroscopy, scanning electron microscopy and X-ray photoelectron spectroscopy. The experimental results show that the addition of 5 wt.% silver into the catalyst is beneficial to the reduction of the catalyst, the surface acidity of the catalyst and the distribution of copper particles in the catalyst, thus increasing the conversion of glycerol and the yield of propylene glycol. When 5wt.% silver and 15wt.% copper are simultaneously loaded on the surface of alumina carrier, the catalyst has higher acidity, better dispersion and larger surface area of copper, so the catalytic effect of the catalyst is better. In addition, the effects of metal content, metal impregnation sequence, reaction temperature, reaction pressure, reaction time, reaction solvent and solvent acidity and alkalinity on the reaction and the reusability of the catalyst were studied in detail. When the optimized 5Ag-15Cu/A1203 catalyst was selected at 22C 鈩，

本文編號(hào)：1901576