负载型铁催化的兴和褐煤的加氢转化

发布时间：2018-06-11 22:33

本文选题：负载型铁催化剂 + 褐煤　；参考：《中国矿业大学》2016年硕士论文

【摘要】：本研究使羰基铁在高压釜中热分解于载体凹凸棒土(AP)上,制备了负载的Fe/AP。对Fe/AP进行多种手段表征,结果显示粒径为5-30 nm的金属Fe纳米粒子成功负载在AP表面,分散性较好,负载量较低,且负载的Fe与AP骨架间具有相互作用。以升华硫为助剂,在氢气氛围下考察了Fe/AP对煤相关模型化合物二(1-萘)甲烷(DNM)的催化性能,结果表明Fe-S/AP对DNM中Car-Cal键的断裂具有很高的催化活性、选择性和稳定性。煤结构本身包含了一些溶剂可溶的分子,这些物质不仅干扰煤转化产物的鉴别,也会影响催化剂的活性和煤样的反应性。使用石油醚、二硫化碳、甲醇、丙酮和等体积二硫化碳/丙酮混合溶剂对兴和褐煤(XL)进行常温分级萃取,尽可能地萃取出XL中的可溶小分子。萃取渣(ER)于甲醇溶剂中在300 oC下发生热溶反应,得到热溶渣(TDR)。利用固体13C核磁共振、X射线光电子能谱、傅立叶变换红外(FTIR)光谱和热重法对XL、ER和TDR进行直接表征,发现萃取并没有破坏XL的骨架结构,XL和ER的大分子组成差别不大;而甲醇热溶可断裂ER中的Cal-Cal、Cal-O、Cal-N和Cal-S等共价键,使TDR与ER间有机结构差异较大。以XL、ER和TDR为反应物,在300 oC条件下分别进行非催化加氢转化(NCHC)与Fe/AP和硫存在时的催化加氢转化(CHC),用FTIR和气相色谱/质谱联用(GC/MS)分析转化产物的分子组成。结果显示XL、ER和TDR的CHC所得可溶组分(SPs)的收率均明显高于NCHC,且ER催化前后SPs的收率增量最大,为20%。表明通过分级萃取分离出XL中的小分子之后,Fe-S/AP对ER的催化作用更明显。根据GC/MS分析,XL、ER和TDR的NCHC和CHC所得SPs的组成包括烷烃、烯烃、芳烃、含氧化合物及少量的含氮和含硫化合物,大部分物质包含烷基(甲基、乙基和异丙基等)结构。烷烃、芳烃和酚是主要的族组分,且CHC的收率显著高于NCHC,尤其是酚和芳烃。烷烃主要为C13-C33的正构烷烃;芳烃的芳环数为1-4且以一环和二环芳烃为主;酚是最重要的族组分,主要包括苯酚、萘酚和茚酚类物质,其中苯酚及其同系物的含量最高。Fe-S/AP催化生成的活性氢原子向XL、ER和TDR中缩合芳环(CARs)本位的添加在断裂与CARs连接的-CH2-和-O-键中发挥了重要的作用,从而CHC提高了烷基芳烃和烷基酚的收率。同时,CHC过程中一些CARs的部分加氢可促进后续Fe-S/AP催化的自由基氢转移反应,并伴随着一些相对较强键的热断裂,形成可溶分子。
[Abstract]:In this study, carbonyl iron was thermally decomposed on attapulgite (APs) in autoclave, and the supported Fe / P was prepared. Fe / AP was characterized by various methods. The results showed that Fe nanoparticles with particle size of 5-30 nm were successfully loaded on AP surface, with good dispersion and low loading amount, and there was interaction between Fe and AP skeleton. The catalytic activity of Fe- / AP for coal related model compound di-1-naphthalene) methanomethane (DNM) was investigated by using sublimated sulfur as promoter in hydrogen atmosphere. The results showed that Fe-Sp-AP had high catalytic activity, selectivity and stability for the fracture of Car-Cal bond in DNM. The coal structure contains some solvent-soluble molecules, which not only interfere with the identification of coal conversion products, but also affect the activity of catalyst and the reactivity of coal samples. Using petroleum ether, carbon disulfide, methanol, acetone and isovolumic carbon disulfide / acetone mixed solvent, Xinghe lignite (XLL) was extracted at room temperature, and the soluble small molecules in XL were extracted as much as possible. TDRN was obtained by thermal dissolution reaction at 300oC in methanol solvent. The solid 13C NMR X-ray photoelectron spectroscopy, Fourier transform infrared spectroscopy (FTIR) and thermogravimetry were used to characterize XLER and TDR directly. It was found that the extraction did not destroy the skeleton structure of XL and the macromolecular composition of XL was not different from that of ER. However, the thermal solution of methanol can break the covalent bonds such as Cal-Calon Cal-OCal-N and Cal-S in ER, which makes the organic structure difference between TDR and ER. Using XLER and TDR as reactants, non-catalytic hydrogenation conversion (NCHCC) with Fe / AP and sulfur was carried out at 300oC, respectively. The molecular composition of the conversion products was analyzed by FTIR and GC / MS. The results showed that the yields of soluble components SPs of XLER and TDR were significantly higher than those of NCHCs. It is shown that the catalytic effect of Fe S / AP on ER is more obvious after the separation of small molecules in XL by stepwise extraction. According to GC / MS analysis, the compositions of NCHC and CHC of XLER and TDR include alkanes, olefins, aromatics, oxygen compounds and a small amount of nitrogen and sulfur compounds, most of which contain alkyl (methyl, ethyl and isopropyl) structures. Alkanes, aromatics and phenols are the main group components, and the yield of CHC is significantly higher than that of NCHCs, especially phenols and aromatics. Alkanes are mainly n-alkanes of C13-C33; aromatic rings of aromatics are 1-4 and mainly monocyclic and dicyclic aromatics; phenols are the most important group components, including phenol, naphthol and indenyl phenols. The content of phenol and its congeners is the highest. Fe-S / AP catalyzes the addition of active hydrogen atoms to the condensed aromatic ring cars in XLER and TDR, which play an important role in the cleavage of -CH2- and -O- bonds connected with CARs. The yield of alkyl aromatics and alkyl phenol was improved by CHC. At the same time the partial hydrogenation of some CARs in CHC process can promote the hydrogen transfer reaction of free radical catalyzed by Fe-S / AP and form soluble molecules with some relatively strong bonds.
【学位授予单位】：中国矿业大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：TQ529.1;O643.36

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