固定床渣油加氢脱金属废催化剂上焦炭结构和组成沿床层变化研究（英文）

针对取自中石油某装置不同床层轴向位置的工业固定床渣油加氢脱金属废催化剂,采用元素分析、热重分析、X射线光电子能谱、傅里叶变换红外光谱和核磁共振碳谱等,研究了催化剂上沉积焦炭的结构组成特征参数。结果表明,不同轴向位置废催化剂上的焦炭具有某些共同特征,如相同的碳类型和官能团等,但其结构和组成各不相同。模拟建立了基于各种表征结果的焦炭结构组成模型,并利用可计算核磁共振波谱化学位移和预测核磁共振谱图的gNMR软件对所建立焦炭模型的精确性进行了验证,表明模型与实验结果具有很好的一致性。     

用碳-14标记化合物研究丁二烯催化剂上的结焦过程

在流动系统中,用碳-14标记化合物研究了丁二烯催化剂上的结焦过程.吸附标记乙醇的升温脱附产物的分析结果表明,吸附态乙醇并不结焦.非标记乙醇与催化剂上的标记焦炭间的交换反应的实验结果,证明在正常反应条件下最初结在催化剂上的焦炭,大部分既不是游离碳,也不是稠环结构.标记乙醛的吸附、脱附和交换实验证明,即使在高达400℃下,催化剂表面上仍可能存有一小部分吸附态的乙醛.由上述结果可以认为,乙醇在催化剂表面上首先生成吸附态乙醛,这种乙醛的一部分转化为丁二烯,一部分随反应时间延长直接地或通过气相逐步缩合成焦炭.     

核磁共振分析技术在重油表征中的研究进展

重油的开发和利用日趋重要。只有对重油的结构和组成有充分的了解,才能合理地利用这部分有限的资源。核磁共振谱图能够直接反映出碳、氢及杂原子所处的化学环境,且分析简便、快捷,从而成为沥青、渣油等重油的结构组成分析的有力工具。本文概述了近年来核磁共振技术在重油结构和组成分析方面所做的主要研究。     

煤焦油重组分甲苯不溶物结构组成及对悬浮床加氢裂化生焦的影响

以煤焦油常压渣油(CTAR)为原料在3000mL环流反应器悬浮床加氢装置上进行了中试实验,并分别从CTAR和加氢产物中提取了甲苯不溶物(TI)及焦炭,通过元素分析、SEM、XRD、FT-IR、XPS等手段对TI及焦炭进行对比分析,明确了TI的结构组成并将其与加氢裂化生焦情况进行了关联。结果表明,CTAR悬浮床加氢工艺具有轻油收率高、生焦总量小、没有壁相焦的特点。TI由煤焦油生产过程中带入的碳质、矿物质颗粒及稠环芳烃有机物构成,O是其中含量最高的杂原子,Ca、Si、Al、Na来源于煤焦油中矿物质,C和O主要存在于C-C、C-H、C-O-C、C-OH结构中,N主要以吡咯和胺的形式存在,S主要以脂肪类S存在。TI具有明显的片层堆积结构,在作用力下容易破碎为具有较大比表面积及吸附能力的微米级微晶及碳质颗粒,和硫化后的催化剂颗粒一起为加氢反应提供载焦中心,优先吸附大分子自由基从而明显减少壁相焦的生成。     

电纺法制备中空多管道碳纳米纤维及其氧还原性能

以过渡金属和新型碳材料为代表的非贵金属催化剂具有成本低、稳定性好等优点,被认为是铂基贵金属催化剂的最佳替代品,对于促进燃料电池商业化应用具有重要意义,其中选择一种简单高效的方法制备符合要求的碳载体成为合成该类催化剂的基础.本实验利用静电纺丝技术制备了中空多管道碳纳米纤维,并深入研究了该材料的氧还原性能.结果表明,具有高度开放结构和较大比表面积的中空多管道碳纳米纤维具有较好的催化活性和电流效率,其极限电流密度为4.06mA/cm~2,电子转移数为3.44,是一种优秀的氧还原催化剂.本论文作者探究了中空多管道结构的形成机理,揭示了催化剂的结构和组成与电催化性能之间的构效关系,证明了中空多管道碳纳米纤维可以作为一种优秀的碳载体应用于非贵金属催化剂中.     

~(13)C-NMR研究高效载体催化剂丙烯立体定向聚合反应机理

<正> 自从用C-NMR技术对聚丙烯进行测定,得到了分辨力良好的聚丙烯甲基碳区域的核磁共振谱后,引起了聚丙烯研究者的极大兴趣,迅速开展了应用核磁共振技术来研究聚丙烯分子链的构型和立体定向聚合机理,众所周知,用不同催化剂体系进行丙烯聚合,得到的聚合物链结构不同,聚合机理也有所差别。Zambelli等认为用Ziegler-Natta型催化剂体系聚合得到的聚丙烯,其聚合机理属于催化剂活性中心控制的单活性中心模型。Yoshio Inoue等用TiCl_4/MgCl_2/C_6H_5COOC_2H_5-AlEt_3 催化剂体系进行丙烯聚合,     

催化剂上积炭结构和组成的分析研究方法

对常用分析研究催化剂上积炭结构和组成的方法,如核磁共振、X射线衍射、红外、拉曼光谱、热分析方法以及紫外可见光谱等现代分析方法的特征和性能进行了综述。指出现代仪器分析方法在考察催化剂积炭行为方面发挥了重要作用,不同方法各具特色,在具体的催化剂表面积炭分析应用中应综合考虑各种方法的优缺点,从而确定最佳表征手段。随着分析仪器的不断发展和完善,仪器分析方法必将在催化剂积炭研究与分析中发挥越来越大的作用。     

芳香环状聚酯二聚体的结构表征

通过基质辅助激光解析电离飞行时间质谱以及核磁共振技术对芳香环状聚酯二聚体的结构进行了表征.质谱分析结果发现除了目标化合物的质子化分子离子峰外,未出现更多的碎片峰,而核磁共振结果对芳香环状齐聚物的氢以及碳的位置给予了确认.从而为芳香环状齐聚物的结构分析提供了一种新的分析方法.     

丙烯水合醚化催化剂上焦炭前身物的表征

采用热重、红外,高温模拟蒸馏和质谱等分析手段,对丙烯水合醚化失活催化剂上的焦炭前身物进行了表征。焦炭前身物主要是沸程范围在200－400℃的长链饱和烃类化合物,四氯化碳洗液和二氯甲烷萃取液的红外和质谱分析均表明,焦炭前身物中没有烯烃和芳烃类化合物存在,β沸石催化剂具有一定的氢转移反应活性,由丙烯聚合生成的聚合烯烃进一步与焦炭前身物通过氢转移反应生成烷烃和焦炭。     

固体氧化物燃料电池直接以焦炭为燃料的电性能

直接碳固体氧化物燃料电池（DC-SOFC）是一种潜在的固体碳燃料高效率、低污染发电技术。本研究报道了将工业焦炭直接用作管式DC-SOFC燃料的研究。制备了电极材料为Ag-GDC （钆掺杂氧化铈）的YSZ （钇稳定化氧化锆）电解质支撑型管式固体氧化物燃料电池（SOFC）。采用拉曼光谱、扫描电镜和X射线能谱仪对焦炭燃料进行了性质表征。结果表明,焦炭燃料呈微米级的颗粒状,并含有大量对Boudouard反应有利的缺陷结构。电池以纯焦炭为燃料在850℃取得的最大功率密度为149mW/cm²,在碳燃料表面负载能提高Boudouard反应速率的Fe催化剂后,最大功率密度提高至217mW/cm²。通过电化学测试和尾气表征,分析了恒电流放电过程中电池的性能衰减机制。测试结果证明了将焦炭直接用作全固态DC-SOFC的燃料产生电能的可行性。     

Temperature-programmed oxidation of equilibrium fluid catalytic cracking catalysts

Characterization of coke on equilibrium, fluid catalytic cracking (FCC) catalysts contaminated with metals was investigated using temperature-programmed oxidation (TPO). TPO spectra of spent equilibrium catalysts from cracking of sour imported heavy gas oil (SIHGO) were deconvoluted into four peaks (Peak K, L, M and N). The four peaks were assigned to different types of coke on the catalyst. Peak L in the TPO spectrum was assigned to the 'contaminant' coke in the vicinity of metals. The amount of contaminant coke (Peak L) correlates with metal-contaminant concentration. The size of Peak L which is related to amount of contaminant coke decreased significantly for the spent highly contaminated catalyst pretreated with hydrogen and methane prior to cracking reactions as compared to the non-pretreated catalysts. Since both hydrogen and methane pretreatment can reduce oxidation state of the vanadium that present at high concentrations on the equilibrium catalysts the decrease in the amount of contaminant-coke represented by Peak L was explained by the reduction of the oxidation state of vanadium. Less contaminant coke was produced after the equilibrium catalysts were pretreated using hydrogen and methane gases since reduced vanadium has lower dehydrogenation activity compared to oxidized vanadium. This revised version was published online in August 2006 with corrections to the Cover Date.     

Partial least squares modeling of combined infrared, H NMR and C NMR spectra to predict long residue properties of crude oils

Research has been carried out to determine the potential of partial least squares (PLS) modeling of mid-infrared (IR) spectra of crude oils combined with the corresponding ¹H and ¹³C nuclear magnetic resonance (NMR) data, to predict the long residue (LR) properties of these substances. The study elaborates further on a recently developed and patented method to predict this type of information from only IR spectra. In the present study, PLS modeling was carried out for 7 different LR properties, i.e., yield long-on-crude (YLC), density (D_LR), viscosity (V_LR), sulfur content (S), pour point (PP), asphaltenes (Asph) and carbon residue (CR). Research was based on the spectra of 48 crude oil samples of which 28 were used to build the PLS models and the remaining 20 for validation. For each property, PLS modeling was carried out on single type IR, ¹³C NMR and ¹H NMR spectra and on 3 sets of merged spectra, i.e., IR + ¹H NMR, IR + ¹³C NMR and IR + ¹H NMR + ¹³C NMR. The merged spectra were created by considering the NMR data as a scaled extension of the IR spectral region. In addition, PLS modeling of coupled spectra was performed after a Principal Component Analysis (PCA) of the IR, ¹³C NMR and ¹H NMR calibration sets. For these models, the 10 most relevant PCA scores of each set were concatenated and scaled prior to PLS modeling. The validation results of the individual IR models, expressed as root-mean-square-error-of-prediction (RMSEP) values, turned out to be slightly better than those obtained for the models using single input ¹³C NMR or ¹H NMR data. For the models based on IR spectra combined with NMR data, a significant improvement of the RMSEP values was not observed neither for the models based on merged spectra nor for those based on the PCA scores. It implies, that the commonly accepted complementary character of NMR and IR is, at least for the crude oil and bitumen samples under study, not reflected in the results of PLS modeling. Regarding these results, the absence of sample preparation and the straightforward way of data acquisition, IR spectroscopy is preferred over NMR for the prediction of LR properties of crude oils at site.     

超声波处理对加氢反应前后沥青质单元分子结构的影响

以胜利减渣和沙轻减渣为原料,研究了超声波处理对加氢反应前后沥青质单元分子结构的影响,并结合¹H-NMR数据、沥青质单元分子参数变化和红外光谱分析等结果,用Chem Bio Draw Ultra 2012模拟出不同条件下两种沥青质单元分子的结构。结果表明,超声波处理减少了沥青质的缔合数,使沥青质单元分子发生开环反应和脱烷基侧链反应加剧,改变了沥青质单元分子的结构,对加氢后沥青质单元分子的结构和组成产生重要影响。沥青质单元分子模型可形象体现超声波处理对加氢反应前后沥青质单元分子化学结构的影响,有助于在分子水平上解释超声波处理影响沥青质单元分子的原因。     

Experimental and theoretical IR,Raman, NMR spectra of 2‐, 3‐, and 4‐nitrobenzoic acids

The influence of the position of nitro group toward the carboxylic group on the vibration structure of the molecule was estimated. Optimized geometrical structures were calculated (HF, B3PW91, B3LYP). Experimental and theoretical FT‐IR, FT‐Raman, and nuclear magnetic resonance (NMR) spectra of the title compounds were recorded and analyzed. The most important vibrational bands of nitro and carboxyl groups and the benzene ring were assigned. Wavenumbers and intensities for the three acids studied were compared and discussed. Data of chemical shifts in ¹H and ¹³C NMR spectra of 2‐, 3‐, and 4‐nitrobenzoic acids were analyzed in comparison with benzoic acid molecule. The calculated parameters are compared with experimental characteristics of these molecules. © 2006 Wiley Periodicals, Inc. Int J Quantum Chem, 2007     

Partial least squares modeling of combined infrared, 1H NMR and 13C NMR spectra to predict long residue properties of crude oils

Research has been carried out to determine the potential of partial least squares (PLS) modeling of mid-infrared (IR) spectra of crude oils combined with the corresponding ¹H and ¹³C nuclear magnetic resonance (NMR) data, to predict the long residue (LR) properties of these substances. The study elaborates further on a recently developed and patented method to predict this type of information from only IR spectra. In the present study, PLS modeling was carried out for 7 different LR properties, i.e., yield long-on-crude (YLC), density (D_LR), viscosity (V_LR), sulfur content (S), pour point (PP), asphaltenes (Asph) and carbon residue (CR). Research was based on the spectra of 48 crude oil samples of which 28 were used to build the PLS models and the remaining 20 for validation. For each property, PLS modeling was carried out on single type IR, ¹³C NMR and ¹H NMR spectra and on 3 sets of merged spectra, i.e., IR + ¹H NMR, IR + ¹³C NMR and IR + ¹H NMR + ¹³C NMR. The merged spectra were created by considering the NMR data as a scaled extension of the IR spectral region. In addition, PLS modeling of coupled spectra was performed after a Principal Component Analysis (PCA) of the IR, ¹³C NMR and ¹H NMR calibration sets. For these models, the 10 most relevant PCA scores of each set were concatenated and scaled prior to PLS modeling. The validation results of the individual IR models, expressed as root-mean-square-error-of-prediction (RMSEP) values, turned out to be slightly better than those obtained for the models using single input ¹³C NMR or ¹H NMR data. For the models based on IR spectra combined with NMR data, a significant improvement of the RMSEP values was not observed neither for the models based on merged spectra nor for those based on the PCA scores. It implies, that the commonly accepted complementary character of NMR and IR is, at least for the crude oil and bitumen samples under study, not reflected in the results of PLS modeling. Regarding these results, the absence of sample preparation and the straightforward way of data acquisition, IR spectroscopy is preferred over NMR for the prediction of LR properties of crude oils at site.     

Structural analysis of alanine tripeptide with antiparallel and parallel beta-sheet structures in relation to the analysis of mixed beta-sheet structures in Samia cynthia ricini silk protein fiber using solid-state NMR spectroscopy

The structural analysis of natural protein fibers with mixed parallel and antiparallel beta-sheet structures by solid-state NMR is reported. To obtain NMR parameters that can characterize these beta-sheet structures, (13)C solid-state NMR experiments were performed on two alanine tripeptide samples: one with 100% parallel beta-sheet structure and the other with 100% antiparallel beta-sheet structure. All (13)C resonances of the tripeptides could be assigned by a comparison of the methyl (13)C resonances of Ala(3) with different [3-(13)C]Ala labeling schemes and also by a series of RFDR (radio frequency driven recoupling) spectra observed by changing mixing times. Two (13)C resonances observed for each Ala residue could be assigned to two nonequivalent molecules per unit cell. Differences in the (13)C chemical shifts and (13)C spin-lattice relaxation times (T(1)) were observed between the two beta-sheet structures. Especially, about 3 times longer T(1) values were obtained for parallel beta-sheet structure as compared to those of antiparallel beta-sheet structure, which could be explicable by the difference in the hydrogen-bond networks of both structures. This very large difference in T(1) becomes a good measure to differentiate between parallel or antiparallel beta-sheet structures. These differences in the NMR parameters found for the tripeptides may be applied to assign the parallel and antiparallel beta-sheet (13)C resonances in the asymmetric and broad methyl spectra of [3-(13)C]Ala silk protein fiber of a wild silkworm, Samia cynthia ricini.     

Experimental (FT-IR, FT-Raman, H, C NMR) and theoretical study of alkali metal 2-aminonicotinates

The influence of lithium, sodium, potassium, rubidium and cesium on the electronic system of 2-aminonicotinic acid (2-ANA) was studied by the methods of molecular spectroscopy. The vibrational (FT-IR, FT-Raman) and NMR (¹H and ¹³C) spectra of 2-aminonicotinic acid and its alkali metal salts were recorded. Characteristic shifts and changes in intensities of bands along the metal series were observed. The changes of chemical shifts of protons (¹H NMR) and carbons (¹³C NMR) in the series of studied alkali metal 2-aminonicotinates (2-AN) were observed too.Optimized geometrical structures of the studied compounds were calculated by the B3LYP method using the 6-311++G** basis set. Aromaticity indices, atomic charges, dipole moments and energies were also calculated. The theoretical chemical shifts in ¹H and ¹³C NMR spectra and theoretical wavenumbers and intensities of IR and Raman spectra were determined. The calculated parameters were compared to the experimental characteristics of the studied compounds.     

The structure of poly(carbonsuboxide) on the atomic scale: a solid-state NMR study

In this contribution we present a study of the structure of amorphous poly(carbonsuboxide) (C3O2)x by 13C solid-state NMR spectroscopy supported by infrared spectroscopy and chemical analysis. Poly(carbonsuboxide) was obtained by polymerization of carbonsuboxide C3O2, which in turn was synthesized from malonic acid bis(trimethylsilylester). Two different 13C labeling schemes were applied to probe inter- and intramonomeric bonds in the polymer by dipolar solid-state NMR methods and also to allow quantitative 13C MAS NMR spectra. Four types of carbon environments can be distinguished in the NMR spectra. Double-quantum and triple-quantum 2D correlation experiments were used to assign the observed peaks using the through-space and through-bond dipolar coupling. In order to obtain distance constraints for the intermonomeric bonds, double-quantum constant-time experiments were performed. In these experiments an additional filter step was applied to suppress contributions from not directly bonded 13C,13C spin pairs. The 13C NMR intensities, chemical shifts, connectivities and distances gave constraints for both the polymerization mechanism and the short-range order of the polymer. The experimental results were complemented by bond lengths predicted by density functional theory methods for several previously suggested models. Based on the presented evidence we can unambiguously exclude models based on gamma-pyronic units and support models based on alpha-pyronic units. The possibility of planar ladder- and bracelet-like alpha-pyronic structures is discussed.