本文選題：鈦 + 周期性介孔有機(jī)硅材料　； 參考：《湘潭大學(xué)》2017年碩士論文

【摘要】：環(huán)氧丙烷是重要的有機(jī)中間體,廣泛應(yīng)用于石油化工、醫(yī)藥、電子工業(yè)及高分子材料等領(lǐng)域。烯烴環(huán)氧化反應(yīng)是制備環(huán)氧化合物的重要途徑,現(xiàn)有的生產(chǎn)方法包括氯醇法、共氧化法和雙氧水氧化法。高選擇性易回收催化劑的開發(fā)仍然是建立高效烯烴環(huán)氧化反應(yīng)體系的關(guān)鍵。本論文在課題組前期研究工作的基礎(chǔ)上,進(jìn)一步優(yōu)化了鈦摻雜苯基橋連有序介孔有機(jī)硅(Ti-PMOs)的制備條件,在環(huán)己烯環(huán)氧化指針?lè)磻?yīng)中考察其催化性能和重復(fù)使用性能,繼而將Ti-PMOs應(yīng)用于叔丁基過(guò)氧化氫為氧源的丙烯環(huán)氧化反應(yīng)體系,優(yōu)化工藝條件,探尋構(gòu)效關(guān)系,為丙烯環(huán)氧化新催化體系的開發(fā)提供研究積累。首先,采用一步水熱合成法在酸性條件下制備出Ti-PMOs催化劑,并對(duì)其進(jìn)行硅烷化改性。為了匹配鈦源鈦酸四丁酯(TBOT)和硅源的水解速率,考察了水解抑制劑種類和用量對(duì)Ti-PMOs催化劑結(jié)構(gòu)的影響,通過(guò)FT-IR、UV-Vis、N2物理吸附等手段對(duì)催化劑進(jìn)行表征。結(jié)果表明:相對(duì)于乙酰丙酮,以H2O2為水解抑制劑,且n(TBOT):n(H2O2)=0.02:12時(shí),Ti-PMOs催化劑的活性鈦含量最高。將該催化劑應(yīng)用于以TBHP為氧源,烯過(guò)比為2:1的環(huán)己烯環(huán)氧化反應(yīng),在80℃下反應(yīng)5h,獲得了37.4%的環(huán)己烯轉(zhuǎn)化率,100%的環(huán)氧環(huán)己烷選擇性。其次,為探索Ti-PMOs催化劑的重復(fù)使用性能,采用溶劑洗滌、抽濾等步驟對(duì)催化劑進(jìn)行了兩次回收。將回收后的催化劑進(jìn)行一系列表征,結(jié)果表明:經(jīng)一次回收后的催化劑骨架中的活性鈦流失明顯,而經(jīng)二次回收后其活性鈦含量幾乎不變。將回收的催化劑應(yīng)用于環(huán)己烯環(huán)氧化指針?lè)磻?yīng)中,結(jié)果為經(jīng)一次和二次回收的催化劑環(huán)己烯轉(zhuǎn)化率分別下降至25.9%和24.8%,環(huán)氧環(huán)己烷的選擇性分別下降至97.7%和93.0%,生成少量副產(chǎn)物環(huán)己酮和環(huán)己二酮。最后,為進(jìn)一步明確催化劑的結(jié)構(gòu)特征,選用NH3-TPD、顯微激光拉曼光譜對(duì)比了Ti-SBA-15、Ti-PMOs及Ti-PMOs-S(硅烷化)中鈦的存在形式及其分布。同時(shí),將上述催化劑用于以TBHP為氧源的丙烯環(huán)氧化反應(yīng)中,結(jié)果表明:有機(jī)硅源的加入和硅烷化修飾有利于活性四配位鈦的形成,提高了催化劑的活性。以Ti-PMOs-S為催化劑,考察了溶劑種類、反應(yīng)溫度、烯過(guò)比、反應(yīng)時(shí)間等因素對(duì)丙烯環(huán)氧化反應(yīng)的影響。結(jié)果表明:以乙腈為溶劑,烯過(guò)摩爾比為6.5:1,在120℃下反應(yīng)2h時(shí),Ti-PMOs-S催化丙烯環(huán)氧化的效果最佳,TBHP的轉(zhuǎn)化率為95.8%,環(huán)氧丙烷和叔丁醇的選擇性(以TBHP計(jì))分別為78.8%和95.9%。
[Abstract]:Propylene oxide is an important organic intermediate, widely used in petrochemical, pharmaceutical, electronic industry and polymer materials. Epoxidation of olefins is an important way to prepare epoxy compounds. The existing production methods include chlor-alcohol method, co-oxidation method and hydrogen peroxide oxidation method. The development of high selectivity and easy recovery catalyst is still the key to the establishment of high efficiency olefin epoxidation reaction system. The preparation conditions of Ti-PMOs were optimized on the basis of the previous work of our research group. The catalytic properties and reusability of Ti-PMOs were investigated in the epoxidation pointer reaction of cyclohexene. Then Ti-PMOs was applied to propylene epoxidation reaction system with tertiary Ding Ji hydrogen peroxide as oxygen source. The optimization of process conditions and the exploration of structure-activity relationship provided a research accumulation for the development of a new catalytic system for propylene epoxidation. Firstly, Ti-PMOs catalyst was prepared by one step hydrothermal synthesis under acidic conditions and modified by silane. In order to match the hydrolysis rate of titanium tetrabutyl titanate and silicon source, the effects of the type and amount of hydrolysis inhibitor on the structure of Ti-PMOs catalyst were investigated. The catalyst was characterized by FTIR IR UV-VisN 2 physical adsorption. The results show that compared with acetylacetone, H2O2 is used as the hydrolytic inhibitor, and the active titanium content of Ti-PMOs catalyst is the highest in the presence of TBOTH _ 2H _ 2H _ 2O _ 2H _ 2O _ 2H _ 2O _ 2H _ 2O _ 2 = 0.02: 12. The catalyst was applied to epoxidation of cyclohexene at 80 鈩，

本文編號(hào)：1915592