發(fā)布時(shí)間：2018-04-23 09:16

  本文選題：石墨烯 + 釕��； 參考：《成都理工大學(xué)》2016年碩士論文

【摘要】：1,2-丙二醇是一種非常重要的化工原料,同時(shí)也廣泛應(yīng)用于食品,醫(yī)藥,化妝品等其他衛(wèi)生制品領(lǐng)域。以乳酸或乳酸酯為原料直接加氫制備1,2-丙二醇是一條可替代石油等不可再生資源的綠色環(huán)保工藝路線。由于羰基的惰性,乳酸及乳酸酯加氫反應(yīng)一般都是在十分苛刻的條件下進(jìn)行的。使乳酸或乳酸酯在較溫和的條件下加氫生成1,2-丙二醇并提高1,2-丙二醇的選擇性的關(guān)鍵在于開(kāi)發(fā)一種高效的催化劑。負(fù)載型金屬催化劑己被成功地用于許多反應(yīng)體系中,都顯示了良好的催化性能,這為溫和條件下實(shí)現(xiàn)乳酸或乳酸酯加氫反應(yīng)提供了可能。石墨烯是一種新型碳材料,具有超大比表面積,優(yōu)異的機(jī)械強(qiáng)度以及良好的耐酸堿和耐高溫的特性。與此同時(shí),適當(dāng)改變石墨烯的組成還可以有效調(diào)控其熱穩(wěn)定性及化學(xué)性質(zhì)。釕基催化劑在羧酸及羧酸酯的催化加氫反應(yīng)中顯示了良好的催化活性。本文以兩種不同的石墨烯基材料為載體,以金屬Ru為活性組分,合成了兩種不同的催化劑,并探討了兩種催化劑在乳酸乙酯催化加氫反應(yīng)中的催化活性。(1)實(shí)驗(yàn)首先采用化學(xué)還原法(Hummers法)制備了還原氧化石墨烯(RGO),以此為載體,通過(guò)浸漬法負(fù)載貴金屬Ru,制備了Ru/RGO催化劑。通過(guò)XRD、SEM、FTIR、XPS等測(cè)試方法對(duì)石墨烯載體和Ru/RGO催化劑的表征,證實(shí)制備的氧化石墨烯具有較高的氧化程度,片層結(jié)構(gòu)良好;且催化劑中活性組分Ru以非晶態(tài)存在載體上。通過(guò)催化加氫條件的優(yōu)化,當(dāng)Ru/RGO催化劑負(fù)載量為5%,催化劑與底物配比為1:100,在氫氣壓力為5 MPa,反應(yīng)溫度為150℃,反應(yīng)時(shí)間為12 h時(shí),乳酸乙酯轉(zhuǎn)化率和1,2-PDO的選擇性達(dá)到最佳值,分別為:97.6%與98.8%。經(jīng)過(guò)6次催化循環(huán)使用后,Ru/RGO催化劑仍然具有較高的催化活性,乳酸乙酯的轉(zhuǎn)化率可達(dá):95.2%,1,2-PDO的選擇性為:71.9%。(2)以無(wú)金屬酞菁為前驅(qū)體,采用高溫裂解法首次制備了氮摻雜的石墨烯,通過(guò)UV、XRD、SEM、TEM和AFM等測(cè)試技術(shù)的表征,證實(shí)了高溫固相裂解酞菁可以成功制備出氮摻雜石墨烯。(3)采用浸漬法合成了Ru/NG催化劑,并將其用于乳酸乙酯催化加氫反應(yīng)。通過(guò)催化條件的優(yōu)化,當(dāng)Ru/NG催化劑負(fù)載量為5%,催化劑與底物配比為1:100,在氫氣壓力為5 MPa,反應(yīng)溫度為150℃,反應(yīng)時(shí)間為12 h時(shí),乳酸乙酯在該催化劑的作用下轉(zhuǎn)化率可達(dá):99.4%,1,2-PDO選擇性可達(dá)到:98.3%。通過(guò)對(duì)催化劑的循環(huán)研究發(fā)現(xiàn),經(jīng)過(guò)6次催化循環(huán)使用后,Ru/NG催化劑仍然可以保持較高的催化活性,乳酸乙酯的轉(zhuǎn)化率和1,2-PDO的選擇性可以達(dá)到:97.7%和73.8%。比化學(xué)還原法(Hummers法)制備的石墨烯為載體的催化劑的催化性能有所提高,為1,2-PDO的制備提供了一種新的綠色環(huán)保工藝路線,同時(shí)NG有望成為一種性能穩(wěn)定的新型催化劑載體。
[Abstract]:Propanediol is a very important chemical raw material, but also widely used in food, medicine, cosmetics and other sanitary products. The direct hydrogenation of lactic acid or lactate to propanediol is a green environmental protection process instead of petroleum and other non-renewable resources. Due to the inertia of carbonyl group, the hydrogenation of lactic acid and lactate is generally carried out under very harsh conditions. The key to hydrogenation of lactic acid or lactate to 1m2-propanediol under mild conditions and to improve the selectivity of lactic acid or lactate is to develop an efficient catalyst. Supported metal catalysts have been successfully used in many reaction systems and have shown good catalytic performance, which provides the possibility for the hydrogenation of lactic acid or lactate under mild conditions. Graphene is a new type of carbon material with high specific surface area, excellent mechanical strength, good acid and alkali resistance and high temperature resistance. At the same time, the thermal stability and chemical properties of graphene can be effectively controlled by changing the composition of graphene. Ruthenium-based catalysts showed good catalytic activity in the hydrogenation of carboxylic acids and carboxylic esters. In this paper, two kinds of catalysts were synthesized with two kinds of graphene based materials as support and metal Ru as active component. The catalytic activity of two catalysts in the hydrogenation of ethyl lactate was studied. Firstly, the reductive graphene oxide RGOA was prepared by chemical reduction method (Hummers method). The catalyst was prepared by impregnating the noble metal Ru. on the carrier. The graphene support and Ru/RGO catalyst were characterized by X-ray photoelectron spectroscopy (XPS). It was proved that the prepared graphene oxide had a high oxidation degree and a good lamellar structure, and the active component Ru in the catalyst existed on the support in amorphous state. Through the optimization of hydrogenation conditions, when the amount of Ru/RGO catalyst is 5, the ratio of catalyst to substrate is 1: 100, the hydrogen pressure is 5 MPa, the reaction temperature is 150 鈩，

本文編號(hào)：1791340