本文關(guān)鍵詞： 氮摻雜碳材料 鈀炭催化劑 維生素E 炔醇 三甲基苯醌　出處：《浙江大學(xué)》2017年碩士論文　論文類型：學(xué)位論文

【摘要】：維生素E是人體必需但是不能自行合成的維生素之一,在調(diào)節(jié)人體的生育功能以及抗氧化功能上發(fā)揮著重要的作用,因而其成為維生素產(chǎn)業(yè)的三大支柱產(chǎn)品之一。在工業(yè)上,廣泛采用以異植物醇與三甲基氫醌縮合的方法制備維生素E。在這一合成路徑中,又可以分為苯環(huán)部分的合成和異植物鏈部分的合成。其中相關(guān)炔醇及三甲基苯醌的選擇性加氫分別作為兩部分的必經(jīng)步驟,有著十分重要的地位。在炔醇的選擇性加氫過(guò)程中,傳統(tǒng)意義上的林德拉催化劑有著水溶液中無(wú)法循環(huán)套用和重金屬(Pb)危害環(huán)境的缺陷。而在傳統(tǒng)的三甲基苯醌的還原工藝中,使用化學(xué)還原劑還原的方法也有著過(guò)量試劑污染環(huán)境的缺陷。近年來(lái),多相催化反應(yīng)以其催化劑的可回收利用和低成本而在工業(yè)催化中具備十分顯著的優(yōu)勢(shì)。其中碳基催化劑,尤其是氮摻雜碳材料,以其原料綠色成本低、獨(dú)特的物理化學(xué)性質(zhì)、高效的催化活性受到了極大的關(guān)注。關(guān)于炔醇的催化選擇性加氫部分,本論文以生物質(zhì)衍生物——氨基葡萄糖鹽酸鹽(GAH)和氧化鋅作為原料,一鍋法得到氮摻雜碳(CN)和氧化鋅的復(fù)合載體。而后在其上浸漬負(fù)載鈀納米顆粒高溫還原得到催化劑(PdZn/CN@ZnO)。在異植物醇關(guān)鍵中間體2-甲基-3-丁炔-2-醇(MBY)選擇性加氫制備2-甲基-3-丁烯-2-醇的反應(yīng)中,相比于PdZn/ZnO,PdZn/CN@ZnO催化劑的催化活性有了明顯的提升(6倍),同時(shí)其選擇性基本保持不變(92%)。進(jìn)一步通過(guò)反應(yīng)條件的優(yōu)化和添加劑的使用,烯醇的收率能夠達(dá)到95%。相關(guān)表征和理論計(jì)算揭示PdZn/CN@ZnO高選擇性的原因是Zn原子對(duì)邊角位Pd原子的替代效應(yīng),高活性的原因是材料的水溶液分散性提升以及PdZn和CN的相互作用。該催化劑顯示了良好的循環(huán)套用性能(9次),在擴(kuò)展其他工業(yè)底物的測(cè)試中也有著優(yōu)異的表現(xiàn)。在三甲基苯醌的催化選擇性加氫部分,本論文以工業(yè)廢炭為原料,通過(guò)引入碳酸氫鉀和草酸銨化學(xué)活化的方法,得到高比表面積的活化氮摻雜活性炭載體(ANAC),而后通過(guò)浸漬鈀前驅(qū)體和甲酸還原法得到催化劑(Pd/ANAC)。當(dāng)其應(yīng)用于三甲基苯醌(TMBQ)的選擇性加氫時(shí),選擇性大于99%,催化活性是未活化鈀炭催化劑(Pd/AC)的將近3倍。進(jìn)一步的反應(yīng)測(cè)試能夠得到該反應(yīng)的反應(yīng)動(dòng)力學(xué)參數(shù),反應(yīng)相對(duì)于底物三甲基苯醌呈現(xiàn)一級(jí)動(dòng)力學(xué)特征(即a=1),相對(duì)氫氣壓力的級(jí)數(shù)b=1.05,反應(yīng)活化能為56kJ/mol,這些數(shù)據(jù)能夠?yàn)槿谆锦拇呋託涔I(yè)生產(chǎn)提供指導(dǎo)意義。綜上所示,本論文通過(guò)實(shí)現(xiàn)生物質(zhì)原料和廢棄物的轉(zhuǎn)化,制備得到氮摻雜改性的鈀炭催化劑,實(shí)現(xiàn)了炔醇和三甲基苯醌的高效選擇性加氫,為維生素E的高效合成提供一定的借鑒意義。
[Abstract]:Vitamin E is one of the essential but not self-synthesized vitamins, which plays an important role in regulating the reproductive and antioxidant functions of the human body, so it has become one of the three pillars of the vitamin industry. Vitamin E is prepared by condensation of iso-phytol with trimethylhydroquinone. The selective hydrogenation of related alkynols and trimethylbenzoquinones is a necessary step of the two parts, and plays a very important role in the selective hydrogenation of alkynyl alcohols. In the traditional sense, Lindela catalyst has the defects that it is impossible to recycle in aqueous solution and heavy metal Pb) is harmful to the environment, but in the traditional reduction process of trimethylbenzoquinone, In recent years, heterogeneous catalytic reactions have a significant advantage in industrial catalysis due to their recoverability and low cost. In particular, nitrogen-doped carbon materials have attracted great attention for their low green cost, unique physical and chemical properties and high catalytic activity. In this paper, the biomass derivative, glucosamine hydrochloride (GAH) and zinc oxide, were used as raw materials. Nitrogen-doped carbon monoxide (CNN) and zinc oxide were prepared by one-pot method, and then impregnated with supported palladium nanoparticles for high temperature reduction to obtain catalyst PdZnR / CNCNZnO.Selective hydrogenation of 2-methyl-3-butyne-2-butyne-2-ol MBY was carried out in the key intermediate of isophytol. In the reaction of 2-methyl-3-butene-2-ol, Compared with PdZn / ZnO- / PdZn/ CN@ ZnO catalyst, the catalytic activity of PdZnR / CN@ ZnO catalyst has been significantly improved by 6 times, and its selectivity has remained basically unchanged. Further, through the optimization of reaction conditions and the use of additives, The yield of enol can reach 95%. The reason for the high selectivity of PdZn/CN@ZnO is the substitution effect of Zn atom on PD atom. The high activity is due to the dispersion of aqueous solution of the material and the interaction between PdZn and CN. The catalyst shows good cycling performance for 9 times and has excellent performance in the test of extending other industrial substrates. In the catalytic selective hydrogenation of trimethylbenzoquinone, In this paper, chemical activation of potassium bicarbonate and ammonium oxalate was carried out using industrial waste carbon as raw material. The activated nitrogen doped activated carbon carrier with high specific surface area, Anacron, was prepared by impregnating palladium precursor and formic acid reduction method to obtain catalyst PD / A NACN. When the catalyst was applied to the selective hydrogenation of trimethylbenzoquinone (TMBQ), The selectivity is greater than 990.The catalytic activity is nearly three times higher than that of the unactivated palladium / carbon catalyst PD / AC. The kinetic parameters of the reaction can be obtained by further reaction test. The reaction shows first-order kinetic characteristics in relation to the substrate trimethylbenzoquinone (i.e., a ~ 1 ~ (-1)), the order bn _ (1.05) relative to hydrogen pressure, and the activation energy of the reaction is 56 kJ / mol. These data can provide guidance for the commercial production of trimethylbenzoquinone in catalytic hydrogenation. In this paper, nitrogen-doped palladium and carbon catalysts were prepared through the conversion of biomass raw materials and wastes, and the selective hydrogenation of alkynyl alcohol and trimethylbenzoquinone was realized, which provided some reference for the high efficiency synthesis of vitamin E.
【學(xué)位授予單位】：浙江大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2017
【分類號(hào)】：O643.36;TQ466.5

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相關(guān)期刊論文 前1條

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本文編號(hào)：1544252