新型拓扑指数和神经网络研究咪唑啉衍生物的缓蚀性能

 基于分子图论提出了一种用于表征咪唑啉衍生物分子局部化学微环境及原子杂化状态的新颖结构描述子,即电性连接性指数⁰K^v、¹K^v和咪唑啉环非氢原子平衡总电荷分数 MCI,用于研究15种咪唑啉类缓蚀剂抗 CO₂、H₂S 腐蚀性能的定量构效关系。结果表明,模型计算值、留一法交互检验预测值的复相关系数分别为0.9764、 0.9546,所建模型具有良好的稳定性和外部预测能力;同多元回归方法比较,运用人工神经网络法的复相关系数为0.9848,结果更精确;增加咪唑啉环上取代基长度、减小分子的支化度和降低咪唑环非氢原子平衡总电荷分数能显著提高咪唑啉缓蚀剂的缓蚀效率。     

Multifunctional Additives Viscosity Index Improvers,Pour Point Depressants and Dispersants for Lube Oil

Abstract

In the present work, some polymeric additives based on styrene-maleic anhydride copolymer were prepared and evaluated as multifunction lube oil additives (viscosity index improvers, pour point depressants, and detergent-dispersant additives). The styrene-maleic anhydride copolymer reacted with different alcohols (dodecyl alcohol, hexadecyl alcohol, octadecyl alcohol, and docosanol) to prepare four different types of esters and aminated with different types of amines (dodecyl amine, hexadecyl amine, and octadecyl amine) to prepare another three co-polymeric additives. Structure of the prepared compounds was confirmed by I.R. spectroscopy. The molecular weights of the prepared copolymers were determined by using gel permeation chromatograph and the percentage of esterification and amination were determined by ¹HNMR. The efficiencies of the prepared compounds as viscosity index improvers, pour point depressants, and detergents-dispersants were investigated. It was found that the efficiency of the prepared compound as viscosity index improvers increases with increasing the concentration of additives in the solution and with increasing the molecular weight of prepared compounds, while the efficiency of the prepared compounds as pour point depressants increases with decreasing the concentration of the prepared polymers. On the other hand, the prepared compounds showed excellent dispersion power.     

影响烷烃辛烷值高低的结构因素

 摘要： 利用量子化学方法计算了40种不同结构C5~C10烷烃分子的电荷分布、前线轨道能量、偶极矩、表面积、体积等反映烃类分子微观特征的电子结构参数和几何结构参数,同时计算了这些烷烃不同类型的拓扑指数。采用遗传函数算法(GFA)对这些烷烃的马达法辛烷值与结构参数之间的关系进行了回归分析,建立了物理意义明确的烷烃辛烷值与其结构参数之间的定量关系方程。该方程揭示了烷烃分子前线轨道间隙和分子表面积是影响其辛烷值高低的主要结构因素。分子前线轨道间隙越低,分子表面积越小,烷烃的辛烷值越高。依据这2个结构参数,利用构建的关系方程,可以对烷烃的辛烷值进行较为准确的预测。方程相关系数平方为0.882,交叉检验相关系数平方为0.848,表明方程具有较强的预测能力。     

Estimating phase behavior of the asphaltene precipitation by GA-ANFIS approach

Abstract

This study implements an adaptive neuro-fuzzy inference system (ANFIS) approach to predict the precipitation amount of the asphaltene using temperature (T), dilution ratio (R_v), and molecular weight of different n-alkanes. Results are then evaluated using graphical and statistical error analysis methods, confirming the model’s great ability for appropriate prediction of the precipitation amount. Mean squared error and determination coefficient (R²) values of 0.036 and 0.995, respectively are obtained for the proposed ANFIS model. Results are then compared to those from previously reported correlations revealing the better performance of the proposed model.     

Mechanochemical-treated Cr-promoted Vanadyl Pyrophosphate Catalyst for n-Butane Oxidation to Maleic Anhydride

Abstract

Cr-promoted vanadium phosphate (VPO) catalyst was synthesized by mechanotreating VOHPO₄·0.5H₂O in cyclohexane for 2 hr using a high energy planetary ball miller followed by calcination in a flow of n-butane/air mixture at 673 K. The physico-chemical properties of the sample were investigated by several characterization techniques such as BET, XRD, redox titration, SEM, and TPR. The data were compared to the unmilled material. BET surface area measurement of the milled catalyst showed that it possesses higher surface area (13.2 m² g^?1) compared to the unmilled catalyst (6.4 m² g^?1). Milling also caused a slight increment in the average oxidation state of vanadium as well as the percentage of V⁵⁺ oxidation state. XRD pattern of the milled material revealed that the major diffraction peaks were broadened thus indicating a reduction of particle size. SEM micrographs showed the lost in the blossom morphology and the formation of layer packages, with more circular particles in the milled catalyst. The amount of active lattice oxygen species being removed from V⁴⁺-O^? pairs increased significantly for mechanochemical treated Cr-doped VPO catalyst leads to the enhancement of the catalytic activity for n-butane oxidation to maleic anhydride.     

STRUCTURAL FEATURES OF ATHABASCA BITUMEN RELATED TO UPGRADING PERFORMANCE

ABSTRACT

Using a combination of instrumental and chemical methods many new classes of compounds appearing as homologous series have been detected in Athabasca oil sand bitumen and in the chemical and thermal degradative products of asphaltene and the heavy ends of maltene. In general, the volatile portion of the maltene is rich in cyclic terpenoid structures and devoid in aliphatic compounds or normal alkane-derived cyclic molecules while the asphaltene fraction and heavy ends of maltene are abundant in normal alkyl-substituted aromatics, thianes, thiolanes, thiophenes, benzo- and dibenzothiophenes

Ru(VM)-catalyzed oxidation permitted the quantitative estimation of the n-alkyl groups attached to aromatic carbons and of n-alkyl bridges between two aromatic units and their concentration distribution according to chain length. It also showed the presence of a large naphthenic core containing cyclic sulfides, which, during oxidation, were converted to their sulfones.     

Synthesis and Evaluation of Some Polymeric Compounds as Pour Point Depressants and Viscosity Index Improvers for Lube Oil

Abstract

In the present study, some polymeric additives were prepared and used as pour point depressants and as viscosity index improvers for lube oil via copolymerization of maleic anhydride and vinyl acetate with different esters of acrylic acid. The molecular weights of the prepared copolymers were determined by GPC. The efficiency of the prepared compounds as pour point depressant and viscosity index improvers was investigated. It was found that the efficiency of the prepared compounds as pour point depressant increases with decreasing the concentration of the prepared polymers, increasing the chain length of alkyl groups, and increases with decreasing the molecular weight. The efficiency of the prepared compounds as viscosity index improvers increases by increasing the concentration of these additives and by increasing the molecular weight of the polymer.     

A novel MLP-ANN approach to predict solution gas-oil ratio

Abstract

The better understanding and estimation of reservoir fluids properties have straight effects on accuracy of different processes such as simulation, well testing, and material balance calculations, so importance of accurate estimation of PVT properties such as solution gas-oil ratio is obvious. To this end, in the present paper, multilayer perceptron artificial neural network (MLP-ANN) is used as a novel predictive tool to estimate solution gas-oil ratio in terms of temperature, bubble point pressure, oil American Petroleum Institute gravity API, and gas specific gravity. Therefore, a total number of 1,137 experimental solution gas-oil ratios has been gathered from reliable databank for evaluation of model outputs. The different graphical and statistical analyses such as determination of average absolute relative deviation (AARD), the coefficient of determination (R²) and root mean square error (RMSE) were used to evaluate the performance of MLP-ANN algorithm. The comparisons show that MLP-ANN algorithm has great accuracy in prediction of solution gas-oil ratio, so it can be used as a simple tool to predict phase behavior of reservoir fluids.     

3-Nitramino-6-hydroxy-1,2,4,5-tetrazine and its alkaline earth metal salts: an effective strategy to balance energy density and safety of energetic compounds

ABSTRACT

3-Nitramino-6-hydroxy-1,2,4,5-tetrazine (NHTZ) and its alkaline earth metal salts (Mg²⁺(1), Ca²⁺(2), Sr²⁺(3), Ba²⁺(4)) were prepared via 3,6-dinitramino-1,2,4,5-tetrazine for the first time. The electrostatic potentials and HOMO-LUMO orbitals of them were computed to better understand the electronic structure of NHTZ. Structures of the four alkaline earth metal salts were confirmed by elemental analysis, IR spectroscopy, and single-crystal X-ray diffraction. Structural analysis revealed that all compounds have differently dimensional structures, increasing with the radius of metal atoms. Compounds 3 and 4 can be classified as coordination polymers due to their structural features. As the only 3D polymeric structure in this series, compound 4 possesses the highest density and best thermal stability in these compounds. Differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) measurement shows the excellent thermal stability of these salts, with the thermal decomposition temperatures of 291.1°C (1), 294.1°C (2), 294.9°C (3) and 324.7°C (4). Heat of formation and sensitivity of the four salts were investigated, which suggest 4 as a potential heat-resistant energetic compound instructions for authors.     

Calculations of heats of formation for nitroaromatics with PM3 and MM2

Abstract

We have attempted to calculate heats of formation (Δ H _f °) for various aromatic nitro compounds with the semi-empirical molecular orbital theory and the molecular mechanics. As the results we may say that PM3, a semi-empirical MO method, and MM2, molecular mechanics, can estimate Δ H _f ° of energetic materials with accuracy enough to use Δ H_f° for energy hazards prediction. In case of aromatic polynitro compounds, both methods may be able to calculate accurate Δ H_f°.     

Study the Influence of Some Polymeric Additives as Viscosity Index Improvers,Pour Point Depressants and Dispersants for Lube Oil

Abstract

In the present work, some polymeric additives were prepared as pour point depressants, viscosity index improvers and dispersant additives for lube oil, these additives prepared by copolymerization of maleic anhydride with different esters of acrylic acids and then amination. The molecular weights of the prepared copolymers were determined by gel permeation chromatograph (GPC). The efficiency of the prepared compounds as pour point depressants and viscosity index improvers was investigated. It was found that the efficiency of the prepared compounds as pour point depressants increases with decreasing the concentration of the prepared polymers, increasing the chain length of alkyl groups and increases with decreasing the molecular weight. The efficiency of the prepared compounds as viscosity index improvers increases by increasing the concentration of these additives and by increasing the molecular weight of polymer. It was found that the amination of polymer enhance the efficiency of the prepared additives as pour point, viscosity index, and dispersant for sludge.     

Estimating Methyl/Methylene Groups in Asphaltene and Other Fractions of Asphalt

Abstract

Infrared is the most widely used analytical method for interpreting the structure of petroleum fractions. In this study, IR spectra of standard normal nonadecane were used to get ε for methyl and methylene groups. A linear relationship was obtained by plotting the peak intensities at 2,954, 2,926, 2,854, 1,466, and 1,376 cm^?1 against different amounts of N-nonadecane. The R ² obtained for most of the plots was in the range of 0.988–0.997. The Beer-Lambert's law was used for the first time to quantitatively estimate the weight percent of methylene and methyl groups present in the different fractions of asphalt.     

Synthesis and Evaluation of Viscosity Index Improvers and Pour Point Depressant for Lube Oil

Abstract

In the present work, four compounds were prepared by copolymerization of maleic anhydride with tetradecene to give (A), and then the copolymer (A) was esterified by a series of n-alkanol having different alkyl chain length. The compositions of prepared compounds were determined by molecular weight and by IR spectroscopy. The efficiency of the prepared compounds as viscosity index improvers for lube oil was studied. From the data, it was found that the efficiency as viscosity index improvers increases by increasing the concentration of these additives and by increasing the alkyl chain length of the alcohol used. The efficiency of the prepared compounds as pour point depressants for lube oil was studied also and shows that the prepared compounds depress the pour point of the lube oil successfully.     

Etherification of FCC Light Gasoline over Mo-Modified β Zeolite Catalyst

Abstract

Etherification activity of several molecular sieve catalysts for FCC light gasoline was studied in a fixed-bed reactor. H-Beta zeolite was found to be high active than that of others and close to cation exchanged resin catalyst. H-Beta zeolite also showed good activity and selectivity and could not be deactivated easily, and could be easily regenerated after deactivation. In order to further improve etherification activity, the surface acidity and pore structure of zeolite could be modified, by loading different metal oxides. The result showed that the highest conversion of tert-olefin was obtained over Mo/Hβ (1%). The influence of reaction temperature, methanol and tert-olefin molar ratio, reaction pressure, and LHSV on the conversion was investigated. At optimized reaction conditions, tert-olefin conversion of 57.42% had been reached with Mo/Hβ (1%).     

STUDY ON THE STRUCTURE OF HEAVY OILS

ABSTRACT

The structural parameters of six heavy oils have been calculated with n-d-M, Brown-Ladner and ¹HNMR/IR method in this paper. The aliphatic H/C atomic ratio Hs/Cs i.e. x values were obtained from IR spectra combining with ¹HNMR spectra. The comparison of structural parameters calculated by ¹HNMR/IR, Brown Ladner and n-d-M methods were carried out for the six heavy oils. It is proposed that the ¹HNMR/IR method gives more precise average molecular parameters than the Brown-ladner method. N-d-M method can gives right molecular structural parameters for some heavy oils with lower molecular weight, but the information of molecular structure obtained by it is limited.     

Novel Energetic Compounds Based on 3-Methyl-1,2,5-Oxadiazole 2-Oxide

Two derivatives of 3-methyl-1,2,5-oxadiazole 2-oxide, (E) 4-methyl-1,2,5-oxadiazole-3-carboxaldehyde 5-oxide (2,4,6-trinitrophenyl)hydrazone (1) and 2,2,2-trinitroethyl 4-methyl-1,2,5-oxadiazole-3-carboxylate 5-oxide (2), were designed, synthesized, and fully characterized. The structures of the new compounds were confirmed by single-crystal X-ray analysis. Physicochemical and energetic properties including density, thermal stability, and sensitivity were investigated, and energetic properties (e.g., detonation velocities and detonation pressures) were calculated using EXPLO5 code. The results indicated that compound 1 exhibits positive heat of formation of 448.0 kJ mol^?1 and acceptable sensitivities (IS: 20 J, FS: 280 N). In addition, compound 2 possesses low melting point (99.92°C), moderate decomposition temperature (183.67°C), good detonation performances (D: 8430 m s^?1; P: 31.5 GPa), and lower sensitivities (IS: 18 J; FS: 220 N), which suggest 2 has the potential to be melt-cast explosive.     

BREAKING WATER-IN-CRUDE OIL EMULSIONS BY NOVEL DEMULSIFIERS BASED ON MALEIC ANHYDRIDE–OLEIC ACID ADDUCT

ABSTRACT

This paper mainly concentrates on synthesis of ten novel demulsifiers and investigate their demulsification efficiency. The demulsifiers were derived from oleic acid–maleic anhydride adduct (OM), which prepared by reaction of oleic acid with maleic anhydride. The reaction was carried out between the OM adduct and the following compounds to form the correspondence demulsifiers; triethanolamine (OMTEA), triglycerol (OMTG), cetylamine (OMCA), triethanolamine with lauryl alcohol (OMTEA–LA), triethanolamine with cetylamine (OMTEA–CA), polyethylene glycol 600 (one mole (OM e.o. 13.6)), polyethylene glycol 600 (two moles (OM e.o. (13.6) 2)), polyethylene glycol 1000 (OM e.o. 22.7), triethanolamine with polyethylene glycol 1000 (OMTEA e.o. 22.7) and triethanolamine with polyethylene glycol 6000 (OMTEA e.o. 136.4). The chemical structures of the OM adduct and some selected demulsifiers were confirmed by ¹H NMR and FTIR. A wide range of demulsifier properties can be obtained by changing the degree of functionalization of the base molecules. The demulsification efficiency of these demulsifiers was tested on w/o emulsions with 10, 30 and 50% water content. From the obtained data, it has found that, the investigated demulsifiers are having a great potential to break the w/o emulsions completely in different times. The (OMTEA e.o. 136.4) was exhibited the minimum time taken to complete separation. The data were discussed on the light of the chemical structure of the demulsifiers and the factors, which effect on the demulsification process.