QSAR for Predicting Biodegradation Rates of Polycyclic Aromatic Hydrocarbons in Aqueous Systems

The relationship between chemical structures and biodegradation rates (k b) of 22 polycyclic aromatic hydrocarbons (PAHs) was studied using density functional theory (DFT) and stepwise multiple linear regression analysis (SMLR) method.The equilibrium geometries and vibration frequency have been investigated at the B3LYP/6-31+G(d,p) level by thinking Solvent effects using a selfconsistent reaction field (SCRF) based on the polarizable continuum model (PCM).It was concluded that the biodegradation rate was closely related to its molecular structure,and there is one high correlation coefficient between the in-plane bending vibration frequency of the conjugated ring of PAHs (Freq) and k b.By means of regression analysis,the main factors affecting the biodegradation rate were obtained and the equation of quantitative structure-activity relationship (QSAR) was successfully established kb =-0.653+0.001Freq+0.068CQ+0.049N1.Statistical evaluation of the developed QSAR showed that the relationships were statistically significant and the model had good predictive ability.The fact that a bending frequency is more important than the HOMO or LUMO energies in predicting k b suggests that the bending of benzene ring might play an important role in the enzymatic catalysis of the initial oxidation step.     

Helical Ullazine-Quinoxaline-Based Polycyclic Aromatic Hydrocarbons

Polycyclic aromatic azomethine ylides (PAMYs) are powerful building blocks in the bottom-up synthesis of internally nitrogen-containing polycyclic aromatic hydrocarbons (N-PAHs) through 1,3-cycloaddition reactions. In this work, the cycloaddition reaction of PAMYs to asymmetric ortho-quinones is presented, which, in contrast to the addition to symmetric para-quinones, facilitates subsequent condensation reactions and allows the synthesis of three helical N-PAHs with ullazine-quinoxaline ( UQ - 1 – 3 ) backbones. UQ - 1 and UQ - 2 possess two helical centers; however, single-crystal X-ray analysis together with the computational modeling of UQ - 3 elucidate the formation of only the thermodynamically most stable geometry with four helical centers in a (P,P,M,M) configuration. For the series UQ - 1 – 3 , the number of redox steps is directly correlated with the number of ullazine or quinoxaline units incorporated into the targeted molecular backbones. A detailed investigation of the spectroscopic and magnetic properties of the radical cation and anion as well as the dication and dianion species by in situ EPR/UV/Vis-NIR spectroelectrochemistry is provided. The excellent optical and redox properties combined with helical geometries render them possibly applicable as chiral emitter or ambipolar charge transport material in organic electronics.     

溴代稠环芳烃的氧化溴化法合成

以HBr/H2O2为溴化体系,采用氧化溴化法合成了6种稠环芳烃的溴化物。 合成反应无需催化剂,通过控制反应温度和溴化试剂用量,可以在稠环芳烃化合物的活性位选择性地单溴化或双溴化,产率可达51.1%～94.2%。 产品经熔点和1H NMR法确认,合成操作简单安全,环境污染少,有工业应用前景。     

高效液相色谱法测定黄浦江表层沉积物中的痕量多环芳烃

建立了高效液相色谱-二极管阵列检测器(PDA)测定上海市黄浦江表层沉积物中16种多环芳烃(PAHs)的方法。在保留时间定性分析的基础上,利用PDA获取的紫外扫描光谱图对目标组分进行了准确的定性,并通过异构体紫外光谱图中特征峰的差异有效地识别了样品中的4种异构体,即苯并［b］荧蒽、 苯并［k］荧蒽、 苯并［a］芘和苯并［e］芘。通过检测波长的优化,减少了干扰物的影响,提高了检测灵敏度;针对分离度较差的两种目标组分(苯并［b］荧蒽和苯并［k］荧蒽)的定量进行了分析讨论。该方法对16种PAHs的检出限(以干基计)介于1.1～18.3 ng/g之间,具有较高的方法灵敏度。黄浦江表层沉积物测定结果表明,除二氢苊外的15种PAHs都被检出,含量为10.1～253.0 ng/g。     

羟基取代的多环芳烃与一氧化氮的反应研究

内源性的一氧化氮(NO)是多种生理过程中必不可少的信使分子,它在神经系统递质传导、神经发育、脑血流调节以及免疫调节等过程中具有十分重要的作用。为揭示NO生理功能的化学本质,NO成为化学家近年来研究的重要课题之一。     

Relationship between the Biodegradability and Structure of Polycyclic Aromatic Hydrocarbons

21 Physicochemical and quantum chemical parameters of 17 kinds of polycyclic aromatic hydrocarbons were calculated by using semi-empirical MOPAC AM1 method. By means of Partial Least Squares （PLS）, quantitative structure-biodegradation relationship （QSBR） study was performed with the logarithm of specific biodegradation rates （logKb）. The optimal model was obtained, and the result showed that the first-order molecular connectivity index （^1X）, the energy of the lowest unoccupied molecular orbital （Elumo）, logarithm of n-octyl alcohol/water partition coefficient （logP） and torsion energy （Et） are the dominant factors governing the biodegradability of polyeyelie aromatic hydrocarbons, and the effect of second-order valence molecular connectivity index （^2X^V）, the third-order valence molecular connectivity index （^3X^V） and molar refractivity （Rm） should not be ignored.     

Polycyclic Aromatic Hydrocarbons Formation from Fuel and Additives Combustion

A study has been made of the effect of additives to the fuel of a turbulent diffusion flame on the formation of soot and polycyclic aromatic hydrocarbons (PAHs). Fuels containing a polystyrene thickener doped with benzene proved to have many advantages over unthickened fuels. Most significant were an increase in the burning time and the flash point. Nevertheless, polystyrene and benzene additives to a considerable extent increased the formation of soot and PAHs. The analysis of PAHs in this study was made by capillary gas chromatography (GC) and capillary gas chromatography/mass spectrometry (GC/MS). A total of 42 individual compounds were characterized by their retention indices and mass spectra.     

气相色谱-质谱法测定塑料玩具中多环芳烃

提出了气相色谱-质谱法测定塑料玩具中16种多环芳烃(PAH′s)含量的方法。样品经正己烷超声提取30min后,40℃水浴氮气吹干。用水、甲醇和正己烷-二氯甲烷(3+2)混合溶剂各5mL溶解残渣,过C18固相萃取柱净化,用正己烷-二氯甲烷(3+2)混合溶液洗脱,所得洗脱液过HP-5MS色谱柱分离,电子轰击离子源检测。16种多环芳烃的质量浓度在0.2～4.0mg·L-1范围内与其峰面积呈线性关系,方法的检出限(3S/N)在0.002～0.021mg·kg-1之间。以聚丙乙烯、聚乙烯、聚氯乙烯或丙烯腈-丁二烯-苯乙烯共聚物等4种材质的塑料玩具为基体,进行加标回收试验,回收率在79.6%～95.2%之间。     

超声-微波协同萃取装置用于土壤中多环芳烃的分析

本研究将开放式微波和直接超声波振荡两种不同的能量方式相结合,研制出超声-微波协同萃取装置。通过萃取土壤中微量多环芳烃(PAHs),对方法和仪器的可行性进行了初步评价。结果表明,在60 mL二氯甲烷-正已烷(1∶1,V/V)的混合萃取剂,100 W微波辐射功率(超声振动功率固定为50 W),萃取9~10m in,土壤中多环芳烃回收率达86.6%,相对标准偏差约4.0%。与索氏抽提、高压密闭和开放式微波等萃取方法相比,本方法具有样品容量大,萃取时间短,萃取效率受样品中含水量和溶剂极性影响小等优点。     

Synthetic Strategies of Carbon Nanobelts and Related Belt-Shaped Polycyclic Aromatic Hydrocarbons

The development of carbon nanobelts and related belt-shaped polycyclic aromatic hydrocarbons has gained momentum in recent years. This Minireview focuses on the synthetic strategies used in constructing these aesthetically appealing molecular nanocarbons. Examples of carbon nanobelts and related belt-shaped polycyclic aromatic hydrocarbons reported in recent years as well as some representative synthetic attempts in earlier times are discussed.     

Analysis of Isomeric Alkylated Polycyclic Aromatic Hydrocarbons by Matrix Isolation Fourier Transform Infrared Spectroscopy

Abstract

Matrix isolation Fourier transform infrared spectra of isomeric methylnaphthalenes and methylbiphenyls, in N₂ matrices at 15 K, are compared with each other and with those of the respective parent hydrocarbons. The applicability of matrix isolation Fourier transform infrared spectroscopy to both identification and quantitative analysis of individual alkylated polycyclic aromatic hydrocarbon isomers in mixtures is demonstrated.     

加速溶剂萃取/气相色谱-质谱测定海洋沉积物中的痕量多环芳烃

沉积物是多环芳烃(polycyclic aromatic hydrocarbons,PAHs)在环境中迁移归趋的一个重要的汇[1]。沉积物中多环芳烃的提取方法主要有索氏提取、超声波提取、微波萃取、加速溶剂提取及超临界流体萃取等。其中加速溶剂提取(accelerated solvent extraction,ASE)由于提取速度快,溶     

Determination of Atmospheric Polycyclic Aromatic Hydrocarbons Using Accelerated Solvent Extraction

Abstract

An accelerated solvent extraction (ASE) method has been developed for the determination of polycyclic aromatic hydrocarbons (PAHs) present in both atmospheric particulate and gaseous phases in this study. Extraction parameters such as the combination of solvents, extraction temperature, and static extraction time were investigated and optimized. Effective extraction was achieved using a 3:1 mixture of n-hexane and acetone as extraction solvents at 100°C in 30 min for all the compounds studied. The optimized extraction method was compared with conventional extraction methods and validated using National Institute of Standards and Technology (NIST)–certified standard reference material (SRM) 1649a. The recoveries obtained for certified 12 PAHs were in the range of 82–126% with relative standard deviation (RSD) between 6 and 28%. The validated ASE technique was used followed by gas chromatography–mass spectrometry (GC-MS) for the determination of PAHs distributed between gaseous and particulate phases in the atmosphere of Singapore. Total average concentrations of PAHs in air samples were 33.54 ± 19.32 ng m^?3, with 4.72 ± 2.80 ng m^?3 in particulate phase and 28.82 ± 16.92 ng m^?3 in gaseous phase, respectively. The results obtained from this study are compared to those reported from other areas of the world.     

Multi-Stage Redox Systems Based on Dicationic P-Containing Polycyclic Aromatic Hydrocarbons

We report the straightforward synthesis of unprecedented electron-acceptors based on dicationic P-containing PAHs (Polycyclic Aromatic Hydrocarbons) based on copper mediated radical approach. In these systems, two phosphoniums are connected through various PAHs backbones. The impact of π-extension on both the optical and redox properties is investigated using a joint experimental (UV/Vis absorption, fluorescence and cyclic voltammetry) and theoretical approach (TD-DFT calculations). Finally, (spectro)-electrochemical studies prove that these compounds possess three redox states and EPR studies confirm the in situ formation of an organic radical delocalized on the PAH backbone.     

Phosphorus-Containing Dibenzonaphthanthrenes: Electronic Fine Tuning of Polycyclic Aromatic Hydrocarbons through Organophosphorus Chemistry

A concise synthetic route towards a new family of phosphorus-containing polycyclic aromatic hydrocarbons starting from the versatile acridophosphine has been established. The structural and optoelectronic properties of these compounds were efficiently modulated through derivatization of the phosphorus center. X-ray crystallographic analysis, UV/Vis spectroscopic, and electrochemical studies supported by DFT calculations identified the considerable potential of these scaffolds for the development of organophosphorus functional materials with tailored properties upon further functionalization.     

X‐Shaped Polycyclic Aromatic Hydrocarbons: Optical Properties and Tunable Assembly Ability

Although a number of synthetic methodologies have been developed to prepare stable polycyclic aromatic hydrocarbons (PAHs), much less research has been devoted to functionalizing the peripheries of molecules to tune the self‐assembly ability or introduce functional groups without altering their photophysical properties. Herein, we report twisted “X”‐shaped molecules prepared through annulation of hexacene with benzoanthracene on the zigzag edge, and an investigation of their photophysical properties and self‐assembly properties. The shape‐complementary “X”‐shaped molecules prefer to dimerize, while the π‐extension would lead to one‐dimensional π‐stacking. Our findings give some insights into the design of stable PAHs without disturbing the electronic structures.     

GC–MS法同时测定聚氨酯塑胶跑道中16种多环芳烃

建立气相色谱–质谱法同时测定聚氨酯塑胶跑道中16种多环芳烃如萘、苊、二氢苊、芴、菲、蒽、荧蒽、苯并[b]荧蒽、芘、苯并[a]蒽、屈、苯并[k]荧蒽、苯并[a]芘、茚并[1,2,3-cd]芘、1-甲基奈、2-甲基萘的检测方法。样品采用甲苯为提取剂,经超声提取和硅胶柱净化后,用气相色谱–质谱法测定16种多环芳烃残留量。16种多环芳烃的质量浓度在0.2~10.0 mg/kg范围内与色谱峰面积呈良好的线性,线性相关系数r20.998,检出限为5.0~60.0μg/kg。回收率为72.4%~101.6%,测定结果的相对标准偏差为0.9%~7.2%(n=6)。该方法准确度高、精密度好,适用于聚氨酯塑胶跑道中多环芳烃多残留检测。     

多环芳烃暴露的生物标志物——尿中羟基多环芳烃

多环芳烃(PAHs) 是典型的持久性有机污染物,在职业高PAHs 暴露环境下,容易诱发肺癌、皮肤癌等癌症。对PAHs 的暴露评价可为流行病学研究和污染物风险评价等提供有效的数据。由于暴露途径的复杂化,采用尿样中PAHs 的代谢产物———羟基多环芳烃作为标志物来综合评价人体对PAHs 的内暴露情况已经成为研究的热点。本文系统介绍了多环芳烃的吸收、代谢、尿中PAHs 代谢产物的主要存在形式、主要的生物标志物以及它们的主要影响因素。     

原油空气氧化前后多环芳烃组分的气相色谱-质谱分析

采用柱层析法对空气氧化前后的原油进行族组分分离,利用气相色谱-质谱(GC-MS)分离测定其芳香烃组分,分析多环芳烃组分的变化.结果表明,随着氧化过程的进行,烷基化多环芳烃占多环芳烃的含量从氧化前的71.5%增加到92.0%(175℃)和90.2%(225℃).轻质组分萘和菲的优势逐渐被重质组分艹屈取代.侧链少的多环芳烃比侧链多的更易氧化.氧化后,其他稠环化合物蒽、萤蒽、芘、苯并蒽含量降低,苯并萤蒽含量增加;苯并芘在175℃氧化后含量降低,而在225℃氧化后含量增加.与此同时,175℃氧化后生成了原油所不含有的三芳甾烃、联苯和苯并呋喃.     

分子印迹聚合物选择性降低烟气中稠环芳烃类物质

以芘(PYR)为模板,由热引发本体聚合合成了芘分子印迹聚合物(MIP),考察了印迹聚合物的选择性吸附性能,采用Scatchard模型分析了印迹聚合物的结合特性,用离线固相萃取实验考察了印迹聚合物对同类底物的吸附能力,并将芘分子印迹聚合物应用到卷烟滤嘴中,用GC/MS法考察了卷烟主流烟气中稠环芳烃类物质释放量的变化。 结果表明,芘分子印迹聚合物具有选择性降低卷烟烟气中稠环芳烃类物质的功能,当MIP添加量为1.5 mg时,能将卷烟烟气中的苯并[a]芘(B[a]P)、苯并(a)蒽(B[a]A)和苣(CHR)的释放量分别降低31.08%、25.69%和27.33%。