本文選題：乙炔氫氯化反應 + 表觀活化能　； 參考：《內(nèi)蒙古大學》2017年碩士論文

【摘要】：本論文主要研究低含量Au基催化劑,含量為0.25%,作為活性組分,采用載體改性和加入助劑兩個方面對用于乙炔氫氯化反應催化劑性能的研究,采用N2物理吸附,XPS,H2-TPR,C2H2-TPD,TG,TEM和SEM等多種手段對新鮮的和反應后的催化劑樣品的物相組成、結(jié)構(gòu)性質(zhì)、氧化還原性能、對反應物氣體HC1和C2H2的吸附能力進行對比分析,探索了載體改性和添加助劑后對于低含量的Au基負載型催化劑的催化性能的影響,得出如下結(jié)論。1.采用浸漬法制備了系列硼改性的低含量Au C0.25wt.%)基催化劑并在乙炔氫氯化反應中測試其催化性能并對硼(B)改性前后的催化劑的性能進行對比分析,活性測試結(jié)果表明通過硼(B)改性后催化劑與未改性催化劑相比,在空速為770h-1,溫度為150℃反應條件下,乙炔轉(zhuǎn)化率提高21.4%,氯乙烯的選擇性提高2%左右;結(jié)果表明加入硼(B)物種可以形成B-C-0鍵,從而降低了 Au3+的電子云密度,抑制Au3+→Au0的還原;加入硼(B)物種可以明顯降低催化劑在反應過程中的積碳量,從而提高了催化劑的穩(wěn)定性;發(fā)現(xiàn)反應后的硼(B)改性與未改性催化劑相比,反應后的硼(B)改性催化劑的Au納米粒子粒徑較小,催化劑的活性較高,表明小納米粒子Au有助于乙炔氫氯化反應;乙炔的吸附能力并不是影響催化劑穩(wěn)定性和催化劑的活性的主要原因,然而催化劑對氯化氫的吸附能力是影響催化劑的穩(wěn)定性和活性的主要原因;加入硼(B)后可以顯著的提高催化劑樣品對HC1氣體的吸附能力,從而增強了催化劑的穩(wěn)定性。2.采用B和N對活性炭載體進行修飾,采用浸漬法制備了系列B和N修飾的Au 0.25%/AC催化,研究了不同比例的B和N修飾的催化劑樣品對乙炔氫氯化反應的影響,結(jié)果顯示采用B和N雙修飾活性炭載體后用于乙炔氫氯化反應時,乙炔的轉(zhuǎn)化率可以達到83.5%,與未摻雜樣品相比,乙炔的轉(zhuǎn)化率提高了 22.5%,比單獨的B修飾催化劑樣品提高了 1.6%左右,得出N物種的存在形式對催化劑性能影響較大,總的來說,N物種對催化劑性能的影響大小順序為N物種的活性順序為砒啶類型N嘰咯類型N四類型N。3.采用浸漬法制備了系列鉭(Ta)含量的Au 0.25%X Ta/AC(X=1、3、5、7)雙金屬催化劑以及Au 0.25%/AC單Au催化劑對乙炔氫氯化反應的影響,篩選出最好的Au0.25%-5Ta/AC雙金屬催化劑,乙炔的轉(zhuǎn)化率可以達到85.8%,氯乙烯的選擇性可以達到99%以上,通過N2物理吸附,XPS,H2-TPR,TG和TEM.等各種表征手段,發(fā)現(xiàn)加入Ta后活性組分Au和Ta物種之間存在明顯的相互作用,造成Au3+物種的還有峰向高溫偏移,使得Au3+物種更難被還原,從而提高了催化劑的穩(wěn)定性,繼續(xù)增加Ta物種的含量發(fā)現(xiàn)催化活性有所降低,由于加入金屬Ta物種的量過多,導致催化劑樣品的比表面積的下降,從而降低了催化劑的活性。4.采用浸漬法制備了加入稀土(Ce)助劑后,與活性組分Au組成的Au-Ce雙金屬催化劑,結(jié)果發(fā)現(xiàn)當Au的含量為0.25%,Ce的含量為7%時,Au 0.25%-7Ce/AC催化劑表現(xiàn)出了良好的催化活性,在空速為770 h-1，，原料氣氯化氫和乙炔的比例為1:1.15,反應溫度為150℃時,乙炔的轉(zhuǎn)化率可以達到78%,比單組分Au0.25%/AC催化劑乙炔的轉(zhuǎn)化率高了 17%左右,.同時研究了 Au 0.25%/AC催化劑用于乙炔氫氯化反應時,選擇性較低,采用計算和實驗的方法,我們認為造成Au 0.25%/AC催化劑用于乙炔氫氯化反應氯乙烯的選擇性較低的可能是生成了副產(chǎn)物1,2-二氯乙烷。并且得出加入稀土助劑Ce后可以增大活性組分Au3+物種的電子云密度,從而使得活性組分Au3+物種更加穩(wěn)定,難被還原,從而增強了催化劑的穩(wěn)定性。
[Abstract]:This paper mainly studies the low content Au based catalyst, the content is 0.25%. As the active component, the performance of the catalyst used in acetylene hydrogen chlorination is studied by using the carrier modification and adding additives in two aspects. A variety of methods, such as N2 physical adsorption, XPS, H2-TPR, C2H2-TPD, TG, TEM and SEM, are used for the phase of the fresh and reacted catalyst samples. The composition, structural properties, redox properties, the adsorption capacity of the reactant gas HC1 and C2H2 were compared, and the effect of carrier modification and additive on the catalytic performance of the low content Au based supported catalyst was explored. The following conclusion was drawn that.1. was prepared by the impregnation method for the low content Au C0.25wt.% of series boron modification. The catalytic performance of the catalyst was tested in acetylene hydrogen chlorination and the performance of the catalyst before and after boron (B) modification was compared. The activity test results showed that the conversion rate of acetylene increased by 21.4% and the selection of chloroethylene was 21.4% at the air velocity of 770h-1 and the reaction temperature of 150 C after the modification of boron (B). The result shows that the sex increases about 2%; the results show that the addition of boron (B) species can form the B-C-0 bond, thus reducing the electron cloud density of Au3+ and inhibiting the reduction of Au3+ to Au0. The addition of boron (B) species can obviously reduce the amount of carbon deposition of the catalyst in the reaction process, thus improving the stability of the catalyst, and the modification of the boron (B) and the unmodified catalyst after the reaction is found. Compared, the Au nanoparticles with boron (B) modified catalyst after reaction are smaller in particle size and higher in the activity of the catalyst. It shows that the small nanoparticles Au is helpful to acetylene hydrochlorination, and the adsorption capacity of acetylene is not the main reason for the stability of the catalyst and the activity of the catalyst. However, the adsorption capacity of the catalyst on the hydrogen chloride is influenced by catalysis. The main reason for the stability and activity of the agent is that adding boron (B) can significantly improve the adsorption capacity of the catalyst samples to HC1 gas, thus enhancing the stability of the catalyst.2. by modifying the active carbon carrier by B and N, and using the impregnation method to prepare the Au 0.25%/AC catalysis of a series of B and N modified Au, and study the B and N modification of different proportions. The effect of catalyst samples on acetylene hydrogen chlorination shows that the conversion of acetylene can reach 83.5% when B and N double modified activated carbon carriers are used for acetylene hydrogen chlorination. Compared with the undoped samples, the conversion rate of acetylene is increased by 22.5%, which is about 1.6% higher than that of the single B trimming catalyst, and the N species can be obtained. The existence form has great influence on the performance of the catalyst. In general, the order of the effect of N species on the performance of the catalyst is that the order of the activity of N species is arsenidine type N Serge type N four type N.3., and the Au 0.25%X Ta/AC (X=1,3,5,7) bimetallic catalyst for a series of tantalum (Ta) content is prepared by impregnation method, and the Au 0.25%/AC single catalyst is used for acetylene. The best Au0.25%-5Ta/AC bimetallic catalyst was screened by the effect of hydrogen chlorination. The conversion rate of acetylene could reach 85.8% and the selectivity of vinyl chloride reached over 99%. Through the physical adsorption of N2, XPS, H2-TPR, TG and TEM., it was found that there was an obvious interaction between Au and Ta species after the addition of Ta. The migration of the Au3+ species to the high temperature makes the Au3+ species more difficult to be reduced, thus improving the stability of the catalyst, increasing the content of the Ta species and reducing the catalytic activity. As the amount of the metal Ta species is too much, the specific surface area of the catalyst is reduced, thus reducing the activity.4. of the catalyst. The Au-Ce bimetallic catalyst consisting of the active component Au after adding the rare earth (Ce) additive was prepared. The results showed that when the content of Au was 0.25% and the content of Ce was 7%, the Au 0.25%-7Ce/AC catalyst showed good catalytic activity, at the air velocity of 770 H-1, the proportion of hydrogen chloride and acetylene in the raw gas was 1:1.15, and the reaction temperature was 150 C. The conversion rate of acetylene can reach 78%, which is about 17% higher than that of the single component Au0.25%/AC catalyst acetylene conversion. At the same time, the selectivity of Au 0.25%/AC catalyst in acetylene hydrogen chlorination is low, and the method of calculation and experiment is adopted. We think that the choice of Au 0.25%/AC catalyst for acetylene hydrogen chlorination of ethylene chloride 1,2- two chloroethane, a by-product, was produced, and the addition of rare earth additive Ce could increase the electron cloud density of the active component Au3+ species, thus making the active component of the Au3+ species more stable and difficult to be reduced, thus enhancing the stability of the catalyst.

【學位授予單位】：內(nèi)蒙古大學
【學位級別】：碩士
【學位授予年份】：2017
【分類號】：O643.36

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