本文選題：乙炔氫氯化 + 汞替代　； 參考：《中國科學技術(shù)大學》2017年博士論文

【摘要】：當前工業(yè)上,乙炔法生產(chǎn)氯乙烯過程仍依靠氯化汞催化劑,然而,氯化汞高毒,在反應條件下易被還原成金屬態(tài)汞導致?lián)]發(fā),為環(huán)境和人類健康帶來了巨大壓力。在中國大量應用乙炔法生產(chǎn)氯乙烯的國情下,汞催化劑的替代問題亟待解決。本論文圍繞這個問題,開發(fā)了兩種無金屬的非汞催化劑,表現(xiàn)出優(yōu)異的催化活性和氯乙烯選擇性,以及穩(wěn)定性,具有一定的應用前景。對碳氮基催化劑的工業(yè)應用進行了前期探索,尤其放大制備和反應性能的評價,取得了一定成果;研究了不同非金屬催化劑的反應機理和失活原因,開發(fā)了簡單的再生方法。主要研究內(nèi)容和結(jié)果如下:1.氮摻雜的碳催化劑的研制。以葡萄糖為原料,通過水熱聚合和高溫氨化制備所得。催化劑具有豐富的微孔結(jié)構(gòu)和高的氮摻雜量(10 wt. %以上)。催化劑表現(xiàn)出良好的催化乙炔氫氯化反應的能力,在給定反應條件下,乙炔轉(zhuǎn)化率可達80-90%以上,氯乙烯的選擇性95%左右;催化劑在200℃穩(wěn)定反應300 h以上,反應至600 h其轉(zhuǎn)化率下降至85%;催化劑失活的主要原因為積碳,可以通過在較低溫度下(300℃)空氣中焙燒,再轉(zhuǎn)移至氨氣中焙燒(450℃)實現(xiàn)再生,再生后的催化劑初始轉(zhuǎn)化率80%以上(所用失活催化劑的活性降低至10%以下);2.催化劑在企業(yè)工況下的性能。在同樣乙炔空速條件下,通過提高催化劑裝填量,可增加反應氣體線速度,減少外擴散阻力,提高催化性能。在較高線速度條件下,反應溫度可適當降低,在維持催化活性的前提下減緩反應積碳,延長催化劑穩(wěn)定性。通過降低反應溫度至180℃,提高催化劑裝填量,其穩(wěn)定性可延長至900 h,期間無顯著失活現(xiàn)象;3.多孔氮化硼p-BN催化劑的研制。(1)材料制備和結(jié)構(gòu):以硼酸和三聚氰胺為原料,高溫反應獲得多孔氮化硼,該材料呈六方氮化硼結(jié)構(gòu),具有高的比表面積,豐富的孔結(jié)構(gòu)(微孔和介孔),豐富缺陷和邊界;(2)催化性能:反應結(jié)果表明,催化劑在280℃時乙炔轉(zhuǎn)化率可達99%,氯乙烯選擇性99%,連續(xù)反應1000 h左右失活較為緩慢,乙炔轉(zhuǎn)化率緩慢降至95%,綜合性能優(yōu)于碳氮材料;(3)催化作用機理及失活原理和再生:研究發(fā)現(xiàn)催化劑失活原因為積碳;積碳可通過在較低溫度的空氣氣氛中燒除,燒除積碳后的材料在氨氣氣氛高溫活化后可實現(xiàn)再生。結(jié)合DFT計算,發(fā)現(xiàn)氮化硼的扶手椅邊界具有催化活性,反應遵循Eley-Rideal反應機制,通過吸附活化乙炔實現(xiàn)催化活化;通過動力學模擬,提出了可能的反應路徑,其過程可能涉及一個類似碳正離子的中間物種的形成。
[Abstract]:At present, the production of vinyl chloride by acetylene process still relies on mercuric chloride catalyst. However, mercuric chloride is highly toxic and can easily be reduced to metallic mercury under reaction conditions, resulting in volatilization, which brings great pressure to environment and human health. In China, the substitution of mercury catalyst for vinyl chloride production by acetylene process needs to be solved. In this paper, two kinds of non-mercury-free catalysts without metal have been developed, showing excellent catalytic activity and vinyl chloride selectivity, as well as stability, and have a certain application prospect. The industrial application of carbonitrogen-based catalysts has been explored, especially in the preparation and evaluation of the reaction performance. The reaction mechanism and deactivation of different non-metallic catalysts have been studied, and a simple regeneration method has been developed. The main contents and results are as follows: 1. Development of nitrogen-doped carbon catalyst. Glucose was prepared by hydrothermal polymerization and high temperature ammoniation. The catalyst has abundant micropore structure and high nitrogen doping amount more than 10 wt.%. Under given reaction conditions, the conversion of acetylene is over 80-90%, the selectivity of vinyl chloride is about 95%, and the catalyst is stable at 200 鈩，

本文編號：2016828