DFT-Study on Antioxydant of 3-Alkyl-4-P henylacetylam i no-1H-1,2,4-Triazol-5-O nes and Its Derivatives

In this article, we have performed B3LYP/6-31＋G（d） calculations of geometrical and reaction enthalpies of antioxidant mechanisms for ADPHT 1-4 （3-alkyl-4-phenylacetylamino-lH-1,2,4-triazol-5-ones） and its derivatives： HAT （hydrogen atom transfer）, SET-PT （single electron transfer-proton transfer） and SPLET （sequential proton-loss electron transfer） were investigated in gas and solution-phases. Solvent contribution to enthalpies was computed employing integral equation formalism IEF-PCM （integral equation formalism method） method. It turned out that the lowest BDEs （bond dissociation energies） is obtained for C-H bonds due to captodative effect in various media. Results indicate that HAT mechanism represents the most anticipated process in gas-phase from thermodynamic point of view. But, the SPLET represents the thermodynamically preferred reaction pathway in solvents （2-propanol, acetonitrile, DMF （N,N-dimethylformamide） and water）. The authors showed that bond dissociation energies, IP （ionization potential） and PA （proton affinity） are sufficient to evaluate the thermodynamically preferred mechanism.     

Research on C—C Bond Length Distribution in Hydrocarbon Molecules

The C—C bond dissociation energy(BDE) is a very important data in research of hydrocarbon cracking reactions, because it reflects the difficulty level of chemical reactions.But it is very difficult to obtain the C—C bond dissociation energy(BDE) by experiments,so using quantum chemistry calculation such as density functional theory(DFT) to study the C—C bond dissociation energy is a very useful means.The impact of acceptor substituents and donor substituents on the C—C bond length distribution was studie...     

基于1H NMR和XRD表征重油组分平均分子结构

The chemical structure of heavy oil fractions obtained by liquid-solid adsorption chromatography was character-ized by 1 H nuclear magnetic resonance and X-ray diffraction.The molecular weight and molecular formula of asphaltene molecules were estimated by combining 1 H nuclear magnetic resonance and X-ray diffraction analyses,and were also ob-tained from vapor pressure osmometry and elemental analysis.Heteroatoms,such as S,N,and O atoms,were considered in the construction of average molecular structure of heavy oils.Two important structural parameters were proposed,including the number of alkyl chain substituents to aromatic rings and the number of total rings with heteroatoms.Ultimately,the av-erage molecular structures of polycyclic aromatics,heavy resins and asphaltene molecules were constructed.The number of α-,β-,γ-,and aromatic hydrogen atoms of the constructed average molecular structures fits well with the number of hydro-gen atoms derived from the experimental spectral data.     

Research on Ethylene and Propylene Formation during Catalytic Pyrolysis of Methylcyclohexane

The influence of operating parameters and type of zeolite catalysts on formation of ethylene and propylene during catalytic pyrolysis of methylcyclohexane (MCH) was studied in a laboratory fixed fluidized bed reactor. The results indicated that higher reaction temperature and lower WHSV tended to produce more ethylene and propylene, among which the reaction temperature was an important factor influencing the ethylene formation. Compared with the FAU and BEA type zeolites, the MFI structured zeolite catalyst, thanks to more acid sites and smaller pore diameter of the catalyst, was conducive to the formation of ethylene and propylene. The protonation occurred on different C—C bonds and C—H bonds in the carbon chain of MCH led to different product slates, and the protonation on C—C bonds located at naphthenic ring was favorable to the formation of ethylene and propylene.     

Specifications and Quality of Lube Oil Base Stocks in China

The Chinese standard Q/SHR001-95 for base stocks is compared with the API specifications. The viscosity-temperature characteristics of base stock required by lube oil in use and market demand on oil quality are analyzed. The quality indicators of base stocks in China and other countries are compared. A new classification of base stocks in response to the requirements of modem lube oil is proposed and the research on new technology to produce premium base stocks meeting API specification is recommended on the basis of current base stock processing technology.     

New High Viscosity Ester Base Stocks for Superior Lubricant Formulations

BASF presents a new high viscosity ester base stock technology.Viscosity profiles of these new candidates are comparable to market-known high viscosity PAO types such as PAO 40 and PAO 100.Due to the more polar nature of the new ester base stocks additional benefits can be achieved in terms of friction reduction,energy efficiency or facilitated additive solubilisation against high viscosity PAOs.The superior performance of the new high viscosity ester base stock technology is demonstrated in direct comparison against high viscosity PAO counterparts in industrial gear applications.The basic advantages found herein in industrial gear applications are also of relevance for other lubricant applications such as automotive driveline oil or engine oil applications.As one exemplary area industrial gear applications play a dominant role in modern wind turbines.The latest generation of lubricants used in these turbine gear boxes are required to provide a greater performance in terms of wear protection,durability,foam resistance,shear stability,and oxidation resistance.Common formulations are based on a PAO base stock thickened with high molecular weight PAO polymers to achieve a viscosity of ISO 320 combined with additives to provide wear protection,foam resistance etc.A recent plant outage coupled with high demand for high molecular weight PAO polymers has led to the market becoming aware of potential availability issues.In response to this important challenge BASF has developed a new formulation strategy-based on the new high viscosity ester technology and upon a widely available low molecular weight PAO base stock employing a new concept in a thickening system that avoids the use of high molecular weight PAO polymers.The novel ester base stock can be manufactured at multiple locations and is based on sustainable raw materials that can be sourced from a wide supplier base.     

Study on Tribological Behaviors of Boron-Nitrogen Modified Fatty Acid as Water-Based Lube Additives

A new type of boron - nitrogen modified fatty acid as water base lube additive was prepared and the chemical structure characterized by infrared spectrum. The tribological properties of the additive in water were evaluated by friction testers. The morphographies and tribochemical species of the worn surfaces were analyzed by means of X - ray Photoelectron Spectroscope （XPS）.The results showed that the additive is excellent in increasing load - carrying capacity, anti - wear and friction - reducing abilities of water. The lubrication mechanism is inferred that a high strength adsorption film and a tribochemical reaction film are formed on the rubbing surfaces due to the carder effect of the long chain fatty acid molecules, high reaction activities of nitrogen, electron - deficient orbit of boron and their synergisms.     

Study on Diffusion of Hydrocarbons in FAU and MFI Zeolites by Molecular Simulation and Related Experiments

The diffusion of C4—C24 alkanes, aromatics and cycloalkanes in FAU and MFI zeolites were studied systematically by molecular simulation. The basic data on diffusion energy barriers and the diffusion characteristics of alkanes, cycloalkanes and aromatics in FAU and MFI zeolites were obtained. It was found out that the 12-member-ring openings between the two adjacent super cages limited the diffusion of hydrocarbons in FAU zeolites, and the hydrocarbon molecules diffused more easily in the intersections of MFI zeolite channels than in the straight channels between the intersections. It was more difficult for the molecules to diffuse in the sinusoidal channel of the MFI zeolite than in the straight channel because of the atoms at the corner of sinusoidal channel. The diffusion of three kinds of C6 alkanes was studied by gravity sorption method. The simulation results were well consistent with the experimental results, indicating that the simulation results were convincing.     

Study on the Mechanisms for Baeyer-Villiger Oxidation of Cyclohexanone with Hydrogen Peroxide in Different Systems

The green and effective Baeyer-Villiger oxidation reaction of cyclohexanone for preparing ε-caprolactone is of particular importance in the synthesis of new polymer materials. We have discussed here several mechanism types of Baeyer-Villiger oxidation of cyclohexanone with H2O2 in different reaction systems. Five main types have been addressed, i. e.: (1) the non-catalyzed reaction type, where the C=O of ketones is activated by H+, which is electrolytically dissociated from H2O2 and H2O, to improve the capability of C=O group for accepting the electron pairs; (2) the thermally activated radical reaction type, where the Criegee intermediate is produced via two steps of radical reaction with ·OH attack, with much more hydroxyl radicals being excited in the presence of TS-1 zeolite; (3) the Brnsted acid catalysis reaction type, where both O-O moiety and C=O group could be activated by Brnsted acid; (4) the solid Lewis acid catalyzed C=O of the substrate activation reaction type through enhancing the donor-acceptor interaction between the antibonding π*C=O orbital of cyclohexanone and HOMO of Sn-containing zeolites; and (5) the solid Lewis acid catalyzed H2O2 to form Me-OOH oxidative species by converting the highest occupied molecular orbital (HOMO) of Ti-OOH into a singly occupied molecular orbital (SOMO), making the O-O group highly electrophilic to attack the C=O of cyclohexanone during the Baeyer-Villiger oxidation process. In the end, we have also compared the different mechanisms and put forward our opinions on the development direction of catalytic materials aiming at eco-friendly Baeyer-Villiger oxidation of cyclohexanone in the years to come.     

Study on Property of Salicylaldehyde Schiff Base Metal Complexes for Catalytic Oxidation of Model Sulfides

Seven kinds of Schiff base metal complexes(C1—C7) were synthesized by the reaction of substituted salicylaldehyde Schiff base with cobalt nitrate, nickel nitrate, and copper nitrate, respectively. The oxygen carrying performance, and the catalytic property of complexes for the oxidation of model sulfides 1-hexanethiol, dibutyl sulfide, and 2-methylthiophene along with their influencing factors were explored, while the oxidized products of the model sulfides were also analyzed and characterized. The results show that the catalytic oxidation property of the complexes is determined by their oxygen carrying performance and solubility in n-octane. The oxygen carrying performance of the complexes is mainly affected by the central ion species, the electronic effects, and the spatial effects of the substituents as well as the degree of conjugation. More specifically, the oxygen carrying performance can be improved by enhancing the oxygenation capacity of the central metal ions, increasing the electron donating ability of the ligand substituent, and diminishing the steric hindrance as well as extending the conjugated chain. Complexes C7 were found to be with high oxygen carrying capacity and high solubility in n-octane, which shows the best catalytic oxidation property, and the oxidation conversion rates for 1-hexylthiol, dibutyl sulfide, and 2-methylthiophene are 74.2%, 65.1%, and 22.7%, respectively. Upon using the oxidation catalyst of Schiff base metal complexes, three sulfides can be oxidized by oxygen to form sulfones and sulfoxides. 1-Hexanethiol and dibutyl sulfide will continue to be oxidized to form sulfates and sulfites.     

水和羧酸钙对润滑油氧化产物聚集影响的分子动力学

采用分子动力学(MD)模拟的方法,研究了不同温度下润滑油氧化产生的极性小分子的聚集行为以及水和羧酸钙分子对其聚集的影响。研究结果表明：润滑油氧化产物分子可以通过氢键产生聚集,形成的氢键聚集体相互作用能为14~58 kJ/mol;随着温度的升高,键能较低的氢键不易形成或容易断裂,因此其聚集程度降低;当体系中含有水或羧酸钙分子时,不同温度下均发生明显的聚集,分别形成了润滑油氧化产物包裹的水分子团聚体或羧酸钙分子的聚集体。润滑油氧化产物与水和羧酸钙分子之间的相互作用能分别为24~60 kJ/mol和66~87 kJ/mol,其比各类润滑油氧化产物分子之间形成的氢键聚集体的相互作用能高,稳定性更好,因此可以在温度较高的条件下形成较稳定的聚集体。     

分子动力学模拟研究大分子润滑油氧化产物的运动和聚集行为及其对基础油性能的影响

The mobility and aggregation behavior of macromolecular lubricant oxidation products and their influences on the performance of base stock were probed by molecular dynamics (MD) simulation. The mean squrare displacement (MSD) of molecules was calculated to explore the mobility of molecules. The distribution appearance of lubricant oxidation products in models was acquired to explore the aggregation of molecules. The results show that the mobility of macromolecular oxidation products is lower than that of base stock, and the MSD of macromolecular oxidation products reduces with the increasing macromolecular weight. Macromolecular oxidation products can also decrease the mobility of basic oil. The interaction energy between macromolecules and base stock ascends with the increase of macromolecular weight. Macromolecules with larger molecular weight can affect more basic oil molecules with stronger restriction, which leads to lower mobilities of base stock molecules. There are aggregates formed among macromolecular oxidation products, and the molecules in aggregates are connected by hydrogen bonds. The quantity of hydrogen bonds in aggregates is related to temperature.     

沥青质中官能团结构和氢键的红外光谱表征

利用傅里叶红外光谱表征渣油沥青质和煤焦油沥青质分子的官能团结构,并通过软件Origin 2018对沥青质红外光谱的氢键区、脂肪族碳氢伸缩振动区和C—O区的吸收峰进行分峰拟合。结果表明：两种沥青质均主要以碳、氢元素为主,二者杂原子的含量存在明显差异,但杂原子官能团的类型基本相同;渣油沥青质中的氢键主要是由苯环O—H与芳香醚键中的O原子、O—H自缔合形成的氢键,而煤焦油沥青质中的氢键主要是苯环O―H与芳香醚键中的O原子形成的氢键;与渣油沥青质相比,煤焦油沥青质的烷基侧链更短。     

乙苯液相过氧化反应的自由基动力学模型研究

在140～155℃内,采用半连续实验研究了用乙苯氢过氧化物作为引发剂的乙苯液相过氧化反应动力学。基于烃类氧化的自由基反应机理,将乙苯液相过氧化反应的主产物乙苯氢过氧化物和副产物α-甲基苄醇、苯乙酮分别作为独立组分,根据乙苯氢过氧化物的O—O键均裂、O—H键断裂等不同的引发方式,分别建立了3个相应的自由基动力学模型。通过模型拟合和辨识,发现乙苯氢过氧化物的引发方式主要为O—O键的均裂,O—H键的断裂可以忽略。以乙苯氢过氧化物O—O键的均裂为引发方式的乙苯液相过氧化自由基动力学模型计算值与实验值相对误差小于8%。     

A Quantum Chemistry Study on Structural Properties of Petroleum Resin

The geometries of resins with single-layer (SG), double-layer (DG) and triple-layer (TG) were calculated with the quantum chemistry method. The geometries and net charges of atoms were obtained. The calculated average distances between layers were 0.5348 nm and 0.5051 nm and the action energies were -9.6355 kJ/mol and -32.2803 kJ/mol for resins DG and TG, respectively. Higher electronegative polar atoms can easily form hydrogen bonds with hydrogen atoms of other resin molecules, resulting in resin aggregates. The minimum cross-sectional diameters of resin molecules are too large to enter the pores of zeolite, so they are likely to crack on the surface of zeolite.     

正庚烷脱氢生成烯烃反应的分子模拟

采用基于密度泛函理论的量子化学方法研究了催化重整过程中正庚烷脱氢生成烯烃的反应过程。结果表明,在无催化剂作用下,正庚烷分子的仲碳C-H键优先发生均裂,生成烷基自由基和氢自由基,均裂能在433.80～434.83 kJ/mol范围;中间产物烷基自由基中,与自由基碳相邻的仲碳位的C-H键容易发生均裂生成烯烃,均裂能在187.11～209.18 kJ/mol范围。正庚烷脱氢反应产物主要为2-庚烯和3-庚烯。在Pt催化剂作用下,正庚烷均裂仲碳位C-H键的反应能垒在75.90～78.51 kJ/mol范围,中间产物烷基自由基中,与自由基碳相邻的仲碳位的C-H键均裂的反应能垒为99.63 kJ/mol,说明Pt催化剂有效地降低了烷烃脱氢反应能垒。
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烃分子供氢能力的分子模拟

为考察不同类型烃分子作为供氢剂的可能性及供氢能力的高低,选用基于密度泛函理论的量子化学从头算法,系统地研究了不同类型烃分子不同位置C-H键断裂反应的能垒和反应热。结果表明,在链烷烃和环烷烃中,C-H键断裂由易到难的顺序为叔碳原子C-H键、仲碳原子C-H键、伯碳原子C-H键。与链烷烃和环烷烃相比,四氢萘α位C-H键更易断裂,其供氢能力更强。在四氢萘结构基础上新增1个芳环,并形成9,10-二氢蒽型结构时,其供氢能力进一步增强。     

稠油破乳作用机理的量子化学和分子力学研究

 采用半经验量子化学和分子力学方法，全优化计算了稠油中胶质模型化合物(SG)、双层结构胶质模型化合物 (DG)和含磺酸基团的破乳剂分子插入双层胶质形成的超分子模型(DGHB)的结构，探讨了破乳作用机理。结果表明， DG模型化合物分子间存在氢键，其作用能为 22.8416kJ/mol；含磺酸基团的破乳剂插入胶质双层结构后，破坏了胶质分子间的氢键。计算结果预示，含有强亲水基团的磺酸盐和带支链烷基的破乳剂可破坏稠油中胶质分子间的氢键，起到稠油破乳之功效。     

Dissociation energies of O-H,N-H,and S-H bonds in sulfur-containing antioxidants

The dissociation energies of O-H bonds (D _O-H) of 48 phenol sulfides and N-H bonds (D _N-H) of five amino sulfides were determined from experimental data. The dissociation energies of the bonds were estimated by the method of crossing parabolas from the kinetic data (the rate constants of reactions of peroxyl radicals with these antioxidants). The O-H, S-H, and N-H bond dissociation energies were determined for three hybrid antioxidants (two hydroxythiophenols and one aminophenol): D _O-H = 335.9 kJ mol^?1 and D _S-H = 340.8 kJ mol^?1 for 2-hydroxy-3,5-bis-(1′-phenylethyl)thiophenol, D _O-H = 337.7 kJ mol^?1 and D _S-H = 344.2 kJ mol^?1 for 3,5-bis-(1′-phenylethyl)-4-hydroxythiophenol, and D _O-H = 338.6 kJ mol^?1 and D _N-H = 366.2 kJ mol^?1 for 1-(N-phenylamino)-2-thiol-3-thio-(3′,5′-bis-di-tert-butyl-4′-hydroxyphenyl)-propane.