【正文】 不僅可以使分子原子等微觀粒子的結(jié)構(gòu)形象化、可視化，而且它可以通過結(jié)構(gòu)分析、模擬、數(shù)據(jù)處理，從微觀角度揭示結(jié)構(gòu)與性質(zhì)的關(guān)系。通過以上文獻(xiàn)及數(shù)據(jù)可知，對吡咯的研究在重油和原油中含氮化合物的處理方面無疑有重大指導(dǎo)意義；比較國內(nèi)外對吸附的研究可得知，利用紅外技術(shù)研究吸附的很少，綜上所述，本課題旨在用原位紅外技術(shù)來研究吡咯在NiMo加氫催化劑上的吸附行為，這不僅對未來研究含氮化合物還是吸附行為都有一定的指導(dǎo)意義。將樣品粉末裝填在原位池樣品槽中，升溫至120℃，N2吹掃至譜圖中OH峰消失。Material Studio是一個采用服務(wù)器/客戶機(jī)模式的軟件環(huán)境，它為你的PC機(jī)帶來世界最先進(jìn)的材料模擬和建模技術(shù)。每種模塊提供不同的結(jié)構(gòu)確定、性質(zhì)預(yù)測或模擬方法。這樣，研究對象和催化劑都有了，就可以開始模擬工作了：在DMol3 Tools 模塊來進(jìn)行模擬運算，其中DFT計算采用 Dmol3模塊。3 結(jié)果與討論 吡咯吸附前后紅外光譜圖在紅外光譜圖中，波數(shù)為波長的倒數(shù)，查閱資料可以得到吡咯的峰位置，其中吡咯的特征譜峰出現(xiàn)在波數(shù)為3400cm1處，此位置代表NH的伸縮振動，也就是說此位置的峰是由NH的伸縮振動引起的，出現(xiàn)在波數(shù)為3100 cm1處的特征峰則是由于CH伸縮振動引起的，出現(xiàn)在1529 cm1處的特征峰則是由于C=C伸縮振動引起的，出現(xiàn)在733 cm1處的特征峰由于吡咯環(huán)面外的順式振動引起的，出現(xiàn)在559 cm1處的特征峰由于吡咯環(huán)面外NH振動引起的。與吸附前吡咯的紅外光譜圖相比較，可以看出吸附后的紅外光譜圖發(fā)生明顯的變化，由數(shù)據(jù)可看出，吸附后，特征峰個數(shù)增加，峰的位置也有顯著變化。而與常溫下吸附不同的就是，吸附前在波數(shù)為1530 cm1處的峰的位置顯著移動。觀察以上4圖，可以看出，由于吸附的原因，吡咯的紅外光譜圖發(fā)生明顯的變化，其整體走勢、百分透過率、峰的位置都有所改變。 Material Studio 模擬結(jié)果及分析 吡咯在MoS2上的吸附模擬選擇Forcite Tools模塊，建立吡咯的3D空間結(jié)構(gòu)圖，采用Geometry Optimization進(jìn)行優(yōu)化，： 吡咯的3D結(jié)構(gòu)圖模型建好后，采用 Dmol3模塊，計算方法選用 GGA，函數(shù)設(shè)為 PBE，對吡咯分子進(jìn)行能量的模擬計算，輸出的結(jié)果為E（吡咯）=。其計算參數(shù)設(shè)置如下：計算方法為 GGA，函數(shù)選 PBE，基組采用可極化的雙數(shù)基組（DNP），中心電子的處理用有效核心（DSPP），系統(tǒng)自旋狀態(tài)為Spinrestricted，自洽場（SCF）參數(shù)的建立使總能量收斂至1105Ha。再進(jìn)行其他模型的模擬。，為第三種吸附模型： 吸附模型3，可以看出吡咯環(huán)上的碳碳雙鍵平行吸附在MoS2表面S原子的的邊緣上，吸附后的總能量E（總能量）=。由吸附能計算公式：E（吸附能）= E（吸附后總能量）—E（吸附物）—E（底物），計算得E4（吸附能）=。由結(jié)果可知，其吸附能為正值，同第4的吸附結(jié)果一樣，因此可以說此種吸附模型也不存在，即吡咯環(huán)上的碳碳雙鍵平行吸附在MoS2表面S原子的的邊緣上不成立。3 總結(jié)1. 由紅外實驗數(shù)據(jù)及分析可以得出結(jié)論：真空常溫下吡咯在MoS2表面上的吸附只發(fā)生在吡咯分子的N原子上，而在真空高溫下，吡咯在MoS2表面上的吸附不僅發(fā)生在吡咯分子的N原子上，還發(fā)生在吡咯環(huán)的碳碳雙鍵上。在整個課題的選題、探究實驗方案、數(shù)據(jù)分析和論文撰寫過程中，都是在韓老師的精心指導(dǎo)和幫助下完成。 NiMoS。 Acridine carbazole。 however, only a part of the nickel layer is shown in subsequent figures to summarize the different adsorption modes. The adsorption energies (△Ea) are calculated as the differences in electronic energies between the adsorption plex and clean surface plus gasphase molecule. The negative DEa values indicate that adsorption is an exothermic process.. Adsorption of basic nitrogencontaining pounds Quinoline can be adsorbed on the Niedge of NiMoS with the molecular plane parallel to the Niedge plane via sideon adsorption, or with the molecular plane perpendicular to the Niedge plane as endon adsorption. Several possible adsorp tion modes were studied for both sideon and endon configurations. The sideon configurations resulted in very weak interactions as evidenced by small adsorption energies(△Ea 5 kcal mol1)。 Densityfunctional theory1. IntroductionThe increasing demand for processing heavy oils and vacuum residue, which contain significantly more nitrogen pounds than conventional light crude oils, requires the development of hydrotreating catalysts with higher hydrodenitrogenation (HDN) activity. In order to develop new hydrotreating catalysts with high activity to remove refractory nitrogen pounds present in heavy oils, a detailed understanding of HDN catalysis, including the structure of the catalysts, the electronic configurations of the nitrogen pounds, and the adsorption and reaction mechanisms of basic and nonbasic nitrogen pounds on catalyst surfaces, is required.Molybdenumbased sulfides are widely used in the oil refining industry as hydrotreating catalysts to remove sulfur and nitrogen from heavy oils. The active phase on these hydrotreating catalysts has a MoS2like structure, and active sites are located at edge surfaces of the MoS2[1,2]. Due to extensive experimental and theoretical research, a good understanding of the structure of the active phase at the atomic level and the location of promoters (nickel and cobalt) in the active phase has been achieved. For unpromoted MoS2, the（?010）Sedge and（10 ?0）Moedge are normally covered by bridge sulfur atoms and have very few sulfur vacancies at reaction conditions[3–5]. In the promoted catalysts, cobalt prefers to incorporate into the Sedge and nickel to the Moedge of MoS2 , and the promoted edge surfaces have more vacant sites under typical hydrotreating reaction conditions[6–8].Most nitrogen present in heavy crude oils is in the form of heterocyclic organonitrogen pounds containing basic (pyridinic) or nonbasic (pyrrolic) ring structures[9]. Non basic nitrogen pounds are a significant fraction of the total nitrogen content in heavy oils[10,11]. These nonbasic nitrogen pounds are more difficult to remove than basic nitrogen pounds using conventional NiMoS catalysts. Indeed, it has been shown that a narrow boiling fraction of coker gas oil containing more nonbasic carbazoles and tetrahydrocarbazoles was more inhibitory and deactivated the catalyst to a greater degree in the HDN of quinoline[12].This difference in reactivity has largely been attributed to the weaker adsorptivity of nonbasic nitrogen pounds pared to basic nitrogen pounds[13,14]. Basic and nonbasic nitrogen pounds have distinct electronic structures and properties that determine their differences in adsorption energetics and reaction pathways on catalyst surfaces[15]. Unfortunately, detailed information regarding the adsorption of oganonitrogen pounds on hydrotreating catalyst surfaces has not been reported, specifically for larger organonitrogen molecules in heavy oils containing two or three rings.There are several studies about the adsorption of sulfurcontaining molecules on the unpromoted MoS2 surface, including thiophene[16,17], benzothiophene[18], and diben zothiophene[19,20], which have provided some insights into hydrodesulfurization (HDS) reaction mechanisms. However, no similar work has been done for nitrogencontaining pounds, particularly on the industrially relevant nickel promoted MoS2 catalyst (NiMoS). Previous studies have been reported for the adsorption of pyridine on a hydrogenated MoS2 surface by the CNDO/UHF method[21], and we recently investigated the adsorption of pyridine and pyrrole on a NiMoS catalyst[22]. In the context of hydroprocessing heavy oils, higher molecular weight organonitrogen molecules such as quinoline, indole, acridine, and carbazole bee signific