多环芳烃指纹用于渤海采油平台原油的鉴别

采用气相色谱/质谱方法,对渤海海上4个不同区块、5个平台的6口油井原油进行了烷基化多环芳烃系列化合物和美国环保署（EPA）优先控制多环芳烃系列化合物的准确定性定量分析。通过多环芳烃原始指纹谱图、多环芳烃组分分布模式和特征比值的比较对上述原油进行鉴别。结果证明不同区块的原油中多环芳烃指纹信息不尽相同,即使在同一平台不同油井中所产的原油其指纹也存在一定差异。为确保原油鉴别的准确性,分析过程中必须在仪器的稳定性和样品前处理方面实施严格的质量控制措施。     

综合模拟风化条件下渤海原油中生物标志物及多环芳烃风化规律研究

该文以渤海原油SZ36-1为研究对象进行综合模拟风化实验,探讨了原油中生物标志物及5类多环芳烃(PAHs)组分的分布情况及风化规律。结果表明:经过30 d风化,渤海原油SZ36-1中大部分生物标志物表现出强的稳定性,部分PAHs的分布发生较大改变,其中萘系列化合物损失最严重,相对浓度的损失达80.34%;菲、二苯并噻吩、、芴系列则相对稳定;经t检验分析风化样品测试数据,生物标志物诊断比值表现出良好的稳定性,所选取多环芳烃新诊断比值中,菲和系列、烷基取代二苯并噻吩类、烷基取代芴类的抗风化能力较强,可用于油源鉴别。     

Excess permittivities,excess refractive indices and NMR spectroscopic studies of solutions of 1,2-dibromoethane in aromatic hydrocarbons

Excess permittivities and excess refractive indices data for solutions of 1,2-dibromoethane (DBE) in benzene, toluene, o-xylene, m-xylene and p-xylene over the whole composition range at 25°C have been obtained. The analysis of excess dielectric properties suggests the existence of weak electron donor-acceptor type interactions between 1,2-dibromoethane (DBE) and aromatic hydrocarbons. The equilibrium constants and the dipole moments of the DBE-aromatic hydrocarbon complexes in solutions have been evaluated. Strneght of interaction increases with electron donating power of aromatic hydrocarbons. NMR spectroscopic studies made on these binary liquid systems also provide evidence for the existence of weak electron donor-acceptor type specific interactions between DBE and aromatic hydrocarbons.     

基于主成分和支持向量机浓度参量同步荧光光谱油种鉴别

基于浓度参量同步荧光光谱技术,对不同溢油类型不同油源原油样品集、引入外扰相似油源样品集进行光谱数据采集,获取其浓度同步荧光光谱矩阵Concentration-Synchronous-Matrix-Fluorescence(CSMF),利用主成分分析方法对两套不同层次的原油相关样品集进行了多类分类识别。结果表明:主成分载荷图可以很好地反映各个原油相关样品在油源上的相似程度,结合支持向量机可以实现不同溢油类型及不同油源原油的准确分类,对于引入风化和海水外扰相似油源溢油样品集,两类分类区分的结果远远高于多类分类识别的结果。通过详细的主成分分析讨论,为溢油油种鉴别提供了一种利用多类分类识别,逐步缩减嫌疑样本数量,最后通过两两分类实现溢油样品准确识别的新思路。     

Oil spill identification by high-speed HPLC

The use of high-speed HPLC in oil spill identification problems has been evaluated in terms of analysis time and reliability. The aromatic fraction was analyzed by reverse-phase chromatography on a 3 μm packing, with detection at 210 and 287 nm, in less than 20 minutes. The profiles exhibited by several Spanish and Middle East crude oils were differentiated by simple statistical parameters. The effect of environmental weathering on the samples has also been investigated. An Arabian light crude oil was still identifiable after four months' simulated marine weathering.     

Front Cover: Facile Multicomponent Synthesis of Oxazolidinones from Primary Amines and Cesium (Hydrogen)Carbonate (Eur. J. Org. Chem. 27/2023)

A facile multicomponent, catalyst-free oxazolidinone synthesis from primary aliphatic or aromatic amines, dibromoethane (DBE), and the usage of either cesium carbonate or cesium hydrogencarbonate as the simultaneous base and C1 source is reported. The applicability of this technically simple reaction was demonstrated by a broad scope with generally high yields, enabling concise late-stage functionalization of amino groups into N-substituted oxazolidinones. The proposed operating reaction mechanism consists of a first-step nucleophilic substitution reaction between DBE and the primary amine, followed by the formation of a carbamate or carbonate intermediate and subsequent cyclization. Additional versatility of the herein-developed protocol has been showcased in a medicinal chemistry approach by the generation of an oxazolidinone-modified dipeptidyl peptidase 8 (DPP8) inhibitor.     

Analytical study of various heavy oil residues using a transalkylation reaction

Summary Various atmospheric residues of crude oil [Boscan (Venezuela), Maya (Mexico), Kirkouk (Iraq), Safanyia (Saudi Arabia), Arabian Light (Algeria)] have been analyzed by GC/MS coupling after transalkylation. The transalkylation of atmospheric residues from the aromatic matrix to a light aromatic acceptor was performed after optimization of the reaction, using an acidic catalyst/light aromatic acceptor couple: AlBr₃ slightly hydrated/benzene. The reaction time was about four hours and the temperature 60°C. These conditions allow the best compromise between a maximal transfer of alkyl chains and their minimal degradation, which is necessary in an analytical study.The results presented here demonstrate that heavy oil residues from different sources give qualitatively similar GC chromatograms, and that only the amounts of phenylalkanes obtained after transalkylation may vary. Under these conditions, the transfer yields of alkyl chains (defined as the mass of alkylated light aromatics obtained from 100g of oil fraction treated) are significantly different and are thus proposed as a new characteristic of heavy crude oil fractions and of petroleum residues.A thorough quantiative study of the phenyl alkanes identified indicates that in every residue, the amount of compounds containing ramified alkyl chains is constant, whereas linear alkyl chain amounts were observed to vary. Yields of diphenylalkanes are quite different for each residue. This result suggests that the reticulation of the aromatic matrix is a function of the nature of the oil residue.     

Characterization of heavy petroleum fraction by positive-ion electrospray ionization FT-ICR mass spectrometry and collision induced dissociation: Bond dissociation behavior and aromatic ring architecture of basic nitrogen compounds

This paper examined the bond dissociation behavior and aromatic ring architecture of basic nitrogen compounds in Sudan heavy petroleum fraction. Both broadband and quadrupole isolation modes positive-ion electrospray ionization (ESI) Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) coupled with collision induced dissociation (CID) techniques were used to characterize a low sulfur crude oil derived vacuum residuum (VR). The appropriate CID operating condition was selected by comparing the molecular weight distributions of the basic nitrogen compounds under various CID operating conditions. Both oddand even-electron fragment ions were observed from the mass spectrum, indicating that the heterolytic and homolytic bond cleavages occurred simultaneously during the CID process. The odd-electron fragment ions were predominant in each class species, indicating preferential heterolytic bond cleavages. At the optimal CID condition, the alkyl groups decomposed deeply and just left the aromatic cores of the nitrogen compounds. No significant variation in double bond equivalent (DBE) value was observed between the fragment and parent ions, revealing that the domination of single core structure.     

Validation of short run time LC-ESI (+) MS/MS method for determination of twenty recommended pesticide residues in food based on QuEChERS extraction technique

Food is expected to contain pesticide residues that might have many problems due to their toxicities for human and animals. So, it is very important to detect and quantify the pesticides contamination levels to increase food safety for the human. The target of our study is to analyse a 20 new pesticides including different pesticide classes such as 1 acaricide, 3 fungicides, 2 plant growth regulators, 11 herbicides, 1 insecticide, 1 rodenticide, and 1 metabolite which were selected according to their modern application in the Egyptian agriculture as well as the recommendation of the Egyptian Agriculture Pesticides Committee (APC). The research is focused on the method validation for the routine analysis of the targeted pesticide residues according to the European SANTE/11,813/2017 guideline. The validation was carried out by fortifying of three levels at 0.01, 0.05 and 0.1 mg/kg in four blank matrices: apple, green beans, fennel seeds and rice which represent different classes of food. The most common citrate buffered QuEChERS extraction method and liquid chromatography coupled with triple quadrupole mass spectrometry (LC-MS/MS) device were used. The mass spectrometer was operated in the positive electrospray ionisation ESI (+) mode and the non-scheduled multiple reactions monitoring (MRM) method in a short run time of 16.0 min. The limits of quantifications (LOQs) for all pesticides ranged between 0.01 and 0.05 mg/kg. Good linearity of the method was in the concentration range 0.001–0.5 μg/ml with acceptable correlation coefficients (r²) ≥ 0.99 for all analytes. The average recoveries for all the target pesticide residues were in the range of 70–120% with relative standard deviations RSDs ≤ 20%. The matrix effect was compensated by using the standard addition method. This short run time LC ESI (+) MS/MS Method may help laboratories which deal with the routine pesticide residues analysis in different food samples.     

Screening the origin and weathering of oil slicks by attenuated total reflectance mid-IR spectrometry

The combination of attenuated total reflectance-fourier transform mid-infrared spectrometry (ATR-FTMIR) and multivariate pattern recognition is presented as a fast and convenient methodology to ascertain the source product an oil slick comes from and to evaluate the extent of its weathering. Different types of hydrocarbons (including crude oils, several heavy distillates and the Prestige's heavy fuel oil) were spilled on metallic containers designed ad hoc and their fate monitored by ATR-FTMIR. Not only environmental conditions were considered for weathering but artificial IR- and UV-irradiation. Pattern-recognition studies revealed that the different hydrocarbons clustered at different locations on the score plots and that the samples corresponding to each oil became ordered according to the extent of their weathering. Among them, fuel oil samples coming from the recent disaster of the Prestige tanker off the Galician shoreline showed a distinctive behaviour. Comparison of natural-, IR- and UV-weathering of a crude oil showed that IR solar radiation can be important in oil-weathering, in addition to broadly-reported UV degradation.     

Matching fluorescence spectra of oil spills with spectra from suspect sources

Fluorescence spectroscopy is ideally suited to the analysis of oil spills as it allows chemical information of polycyclic aromatic hydrocarbons to be acquired quickly, sensitively and selectively. Unlike infrared spectra which have detailed peak information, many fluorescence spectra have only a few broad peaks. Nine different samples of crude and diesel oils were used for testing point-to-point matching across the spectral range. Five of them were discriminated by point-to-point matching algorithms and the other four very similar samples were not. Principal components analysis (PCA) did successfully discriminate among all similar samples. PCA could also distinguish the extent of weathering of different samples, an important factor in matching environmental spills.     

Synthesis and characterization of new aromatic polyesters and polyethers derived from 1,2-bis(4-hydroxyphenyl)-1,2-diphenylethylene

New polyarylates and aromatic polyethers were synthesized from 1,2-bis(4-hydroxyphenyl)-1,2-diphenylethylene, and aromatic dicarboxylic acid chlorides and aromatic dihalides, respectively. The polyarylates having inherent viscosities of 0.28–1.05 dL/g were synthesized by either the two-phase method or the high-temperature solution method. All the polymers were easily soluble in N-methyl-2-pyrrolidone, N,N-dimethylformamide, pyridine, m-cresol, 1,4-dioxane, and 1,1,2,2-tetrachloroethane. They have glass transition temperatures in the range of 217–250°C and showed no weight loss below 315°C in both air and nitrogen atmospheres. Aromatic polyethers with inherent viscosities of 0.85–1.21 dL/g were obtained by the polycondensation of 1,2-bis(4-hydroxyphenyl)-1,2-diphenylethylene and aromatic difluorides in the presence of potassium carbonate. These polymers having glass transion temperatures of 193–220°C were also soluble in the aforementioned solvents and stable up to around 350deg;C in both atmospheres. © 1994 John Wiley & Sons, Inc.     

Synthesis,characterization and thermal stability of new dumbbell-shaped isobutyl-substituted POSSs linked by aromatic bridges

Five new dumbbell-shaped polyhedral oligomeric silsesquioxanes (POSSs), in which two identical silicon cages R₇(SiO_1.5)₈ (with R = isobutyl), linked to various aromatic bridges (Ar, Ar–Ar, Ar–O–Ar, Ar–S–Ar and Ar–SO₂–Ar, where Ar = p-C₆H₄) were prepared through a literature method opportunely modified by us to make easier preparation and increase yield, which was higher than 70 % in all cases. The obtained products were the expected ones, as supported by the results of elemental analysis and ¹H NMR spectra. Their resistance to the thermal degradation in both flowing nitrogen and static air atmosphere was checked by degrading samples at 10 °C min^?1 and determining temperatures at 5 % mass loss (T _5%) and residues at 700 °C. The T _5% values in air were lower than the corresponding ones in nitrogen, but the trend among the various POSSs investigated was the same in both used atmospheres, with the most high value for the compound having the Ar–O–Ar aromatic bridge. The residues at 700 °C in air of the compounds having not hetero-atoms (O or S) in the aromatic bridge were higher than those in nitrogen, whilst no substantial difference was observed for the other ones.     

Degradation of TEMPO-oxidized cellulose fibers and nanofibrils by crude cellulase

The biodegradation behavior of 2,2,6,6-tetramethylpiperidine-1-oxyl radical (TEMPO)-oxidized cellulose fibers (TOCs) suspended in water and TEMPO-oxidized cellulose nanofibrils (TOCNs) dispersed in water by a commercial crude cellulase was studied. Products crude cellulase-treated for 0–7 days were separated into water/ethanol-insoluble and -soluble fractions. Weight recovery ratios and viscosity-average degrees of polymerization of the water/ethanol-insoluble fractions clearly decreased with crude cellulase-treatment time, showing that both TOCs and TOCNs have biodegradability. Water/ethanol-soluble fractions were subjected to size-exclusion chromatography (SEC) with photodiode array (PDA) detection to obtain SEC elution patterns detected by reflective index and UV spectra of each SEC pattern elution slice. SEC–PDA and ¹³C-NMR analyses showed that glucuronosyl unit-containing molecules present on microfibril surfaces in TOCs and TOCNs were primarily cleaved by hydrolyzing enzymes present as contaminants in the crude cellulase to form glucuronic acid as one of the major water-soluble degradation compounds. After the glucuronosyl units in TOCs and TOCNs were degraded and removed from microfibril surfaces by the hydrolyzing enzymes, cellulose chains newly exposed on the microfibril surfaces were rapidly hydrolyzed by cellulases predominantly present in the crude cellulase to form cellobiose. Both TOCs and TOCNs having sodium carboxyl groups are thus biodegradable, but TOCN having free carboxyl groups had clearly low biodegradability by the crude cellulase. Thus, biodegradation behavior may be controllable by controlling the structure of carboxyl group counter ions in TOCs and TOCNs.     

Application of solid‐phase microextraction to the determination of polycyclic aromatic sulfur heterocycles in Bohai Sea crude oils

A simple and rapid solid‐phase microextraction approach for the isolation of polycyclic aromatic sulfur heterocycles from the aromatic fraction of crude oil is described. 8‐Hydroxyquinoline silica gel impregnated with palladium chloride was used as a sorbent material for extraction. Operational parameters of the extraction solvents have been evaluated and optimized. Benzothiophene, dibenzothiophene, and benzo[b]naphtho[1,2‐d]thiophene and their C₁–C₄ alkyl derivatives were identified and quantified by GC–MS. Under optimum conditions, the limits of detection for benzothiophene, dibenzothiophene, and benzo[b]naphtho[1,2‐d]thiophene were 0.277, 0.193, and 0.597 μg/g oil, respectively. The recoveries for the polycyclic aromatic sulfur heterocycles ranged from 81.5 to 92.1%, and the linear dynamic range was from 10 to 1000 ng/mL. The developed methodology was tested in the characterization of crude oil samples collected at the DY, SZ, ZH, and HC petroleum oil fields of the Bohai Sea. The results proved that SPE coupled with GC–MS is a promising tool for the quantitative analysis of polycyclic aromatic sulfur heterocycles in crude oils, especially for oil samples with low concentrations of polycyclic aromatic sulfur heterocycles.     

原油中芳香硫化合物形态分布的研究

建立了原油中多环芳香硫化合物形态分布的研究方法。采用氯化钯/硅胶配位交换色谱分离原油中的芳香硫化合物,并用气相色谱/质谱分析、气相色谱-硫化学发光检测法结合色谱保留指数,鉴定出原油中的100多个多环芳香硫化物,包括含烷基取代基的苯并噻吩和二苯并噻吩类硫化物。定量分析表明,二苯并噻吩类化合物的含量占芳香硫化合物总量的91%左右。该方法可用于不同来源的原油中芳香硫化合物的形态分布研究。     

Thermal transformation of acid compounds in high TAN crude oil

The Liaohe crude oil with high total acid number (TAN) was subjected to thermal reaction at 300℃to 500℃. Reaction products were collected and analyzed by negative-ion electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry (ESI FT-ICR MS) to determine acid compounds in the crude oil. The double-bond equivalence (DBE) versus carbon number was used to characterize the oxygenated components in the feed and reaction products. The O2 class which mainly corresponds to naphthenic acids decarboxylated at 350-400℃, resulting in a sharply decrease in TAN. Phenols (O1 class) are more thermally stable than carboxylic acids. Carboxylic acids were also thermally cracked into smaller molecular size acids, evidenced by the presence of acetic acid, propanoic acid, and butyric acid in the liquid product. These small acid species are strong acids likely responsible for corrosion problems in refineries.     

Comparison of single-reflection near-infrared and attenuated total reflection mid-infrared spectroscopies to identify and monitor hydrocarbons spilled in the marine environment

The capability of single-reflection near-IR (NIR) spectroscopy to differentiate, characterize and monitor the fate of a set of hydrocarbons spilled in the marine environment was compared with that of multiple-reflection horizontal attenuated total reflection mid-IR (ATR-MIR) spectroscopy. Multivariate pattern recognition techniques [principal component analysis (PCA), multivariate polynomial regression, cluster analysis and potential curves] were applied to unravel the major trends of the weathering processes of four generic types of crude oils and two heavy fuel oils spilled under controlled conditions for almost 4 months. A chemical interpretation of the NIR spectra related the weathering processes and the PCA loadings, which had not already been done in the literature. Weathering for both light and heavy products was characterized by a contrast among the linear aliphatic structures (more volatile and easy to degrade) and the branched and aromatic structures (more recalcitrant). Potential curves were applied to model each product and determine objectively whether unknown samples could be classified correctly. Polynomial regression on the PCA scores was employed to evaluate the time elapsed from the oil spillage to its sampling; this represents a new approach to assess the age of a hydrocarbon lump. In general, NIR spectroscopy yielded good results when light crude oils were studied, whereas ATR-MIR spectroscopy led to satisfactory results for both light and heavy products.     

Aromatic resin characterisation by gas chromatography-mass spectrometry. Raw and archaeological materials

An analytical procedure based on alkaline hydrolysis, solvent extraction and trimethyl-silylation followed by gas chromatography-mass spectrometry (GC-MS) analysis was used to study the chemical composition of benzoe and storax resins, water-insoluble exudates of trees of the Styrax and Liquidambar genus. They are chemically characterised by having aromatic acids, alcohols and esters as their main components and are thus known as aromatic and/or balsamic resins. This analytical procedure allowed us to characterise the main components of the two resins and, even though cinnamic acid is the main component of both the resins, the presence of other characteristic aromatic compounds and triterpenes permitted us to distinguish between the two materials. All the compounds identified in benzoe resin were detected in an archaeological organic residue from an Egyptian ceramic censer (fifth to seventh centuries a.d.), thus proving that this resin was used as one of the components of the mixture of organic materials burned as incense. These results provide the first chemical evidence of the presence of benzoe resin in an archaeological material from Mediterranean area.     

Synthesis and characterization of new aromatic polyesters and a polyether derived from 2,2-bis(4-hydroxyphenyl)-1,2-diphenylethanone

New polyarylates having benzopinacolone units were synthesized from 2,2-bis(4-hydroxyphenyl)-1,2-diphenylethanone and aromatic dicarboxylic acid chlorides. The polymers having an inherent viscosity of 0.71–0.94 dL/g were obtained by the two-phase method using toluene as an organic solvent. The polymers were easily soluble in various organic solvents and had high glass transition temperatures in the range of 200–240°C. An aromatic polyether having benzopinacolone unit was also prepared. However, its inherent viscosity was low because of the occurrence of a side reaction. © 1998 John Wiley & Sons, Inc. J. Polym. Sci. A Polym. Chem. 36: 2229–2235, 1998