本文選題：環(huán)氧丙烷異構(gòu)化 + 烯丙醇　； 參考：《南京理工大學(xué)》2017年碩士論文

【摘要】：烯丙醇作為基礎(chǔ)化工原料具有廣泛的應(yīng)用,主要原因是其分子結(jié)構(gòu)中同時(shí)具有雙鍵和羥基兩種官能團(tuán),可以參與氧化、還原、醚化、酯化等多種反應(yīng)。目前工業(yè)上常用的制備烯丙醇的方法是氣相環(huán)氧丙烷異構(gòu)化法,具有工藝簡(jiǎn)單,效率高,污染小等優(yōu)點(diǎn)。堿性磷酸鋰催化劑用于環(huán)氧丙烷異構(gòu)化反應(yīng),其催化活性和選擇性都較高,但是催化劑容易因積碳而失活,給連續(xù)生產(chǎn)帶來(lái)極大的不便。針對(duì)以上問(wèn)題,本文對(duì)催化劑分別進(jìn)行水蒸氣預(yù)處理和金負(fù)載的方法有效抑制了積碳的產(chǎn)生,并提高了催化劑的活性。為了找到更加適合環(huán)氧丙烷異構(gòu)化反應(yīng)的催化劑,對(duì)各類(lèi)催化劑進(jìn)行了小范圍的篩選。對(duì)催化劑進(jìn)行水蒸氣預(yù)處理明顯抑制了堿性磷酸鋰催化劑的表面積碳生成,且其催化活性明顯提高。實(shí)驗(yàn)結(jié)果顯示,在300℃下經(jīng)過(guò)水蒸氣處理30 min時(shí),催化劑呈現(xiàn)最好的催化活性。而且,經(jīng)過(guò)水蒸氣處理的催化劑在反應(yīng)12小時(shí)后的積碳量是15.1%,遠(yuǎn)遠(yuǎn)低于未經(jīng)處理的催化劑上的積碳量(21.5%)。實(shí)驗(yàn)證明,經(jīng)水蒸氣處理后,Br(?)nsted酸量的減少可能導(dǎo)致積碳量的減少,而催化劑活性的提高可能是Lewis酸量的增加和強(qiáng)堿強(qiáng)度的增加兩者協(xié)同作用的結(jié)果。金納米顆粒負(fù)載于磷酸鋰表面而得到Au/Li_3PO_4催化劑,此方法明顯提高了磷酸鋰的催化活性。實(shí)驗(yàn)結(jié)果顯示,金的負(fù)載量為0.042 wt%,pH值為13,煅燒溫度為300 ℃時(shí),催化劑呈現(xiàn)最好的催化活性。實(shí)驗(yàn)證明Au/Li_3PO_4催化劑強(qiáng)堿強(qiáng)度的增強(qiáng)導(dǎo)致催化活性提高。通過(guò)XPS和密度泛函理論共同證實(shí)強(qiáng)堿強(qiáng)度增強(qiáng)是因?yàn)殡娮訌牧姿徜嚨难踉愚D(zhuǎn)移到金粒子表面,導(dǎo)致富電子的金粒子表現(xiàn)為堿性更強(qiáng)的堿。為了找到更高活性的催化劑,本文對(duì)各類(lèi)催化劑進(jìn)行了小范圍的篩選,實(shí)驗(yàn)結(jié)果顯示,Ag和Cu對(duì)磷酸鋰催化活性并沒(méi)有明顯的提高,反而一定程度上抑制了磷酸鋰的催化活性。至于TiO2、X型分子篩、g-C3N4、Au-Pd/TS-1、固體超強(qiáng)酸、納米Ag、CeO2-TiO2這幾種催化劑,雖然環(huán)氧丙烷的轉(zhuǎn)化率幾乎都在10%以下,但是丙醛的選擇性幾乎都在50%左右,與磷酸鋰催化劑相比較,這些催化劑呈現(xiàn)較高的丙醛選擇性。所以,在經(jīng)過(guò)催化劑的改性之后,這些催化劑有待成為環(huán)氧丙烷異構(gòu)化制備丙醛反應(yīng)的優(yōu)選催化劑,這部分工作還有待深入研究。
[Abstract]:Allyl alcohol is widely used as a basic chemical raw material. The main reason is that its molecular structure has two functional groups, double bond and hydroxyl group, which can participate in many reactions such as oxidation, reduction, etherification, esterification and so on. At present, gas phase epoxypropane isomerization is the commonly used industrial method to prepare allyl alcohol, which has the advantages of simple process, high efficiency, low pollution and so on. The catalytic activity and selectivity of alkaline lithium phosphate catalyst for the isomerization of propylene oxide is high, but the catalyst is easily deactivated due to carbon deposition, which brings great inconvenience to continuous production. In view of the above problems, the methods of water vapor pretreatment and gold loading can effectively restrain the formation of carbon deposition and improve the activity of the catalyst. In order to find more suitable catalysts for the isomerization of propylene oxide, various catalysts were screened in a small range. The surface area carbon formation of alkaline lithium phosphate catalyst was obviously inhibited by steam pretreatment, and its catalytic activity was improved obviously. The experimental results show that the catalyst exhibits the best catalytic activity after 30 min of water vapor treatment at 300 鈩，

本文編號(hào)：1809080