Single atom doping induced charge-specific distribution of Cu1-TiO_(2) for selective aniline oxidation via a new mechanism

Utilizing single atom sites doping into metal oxides to modulate their intrinsic active sites,achieving precise selectivity control in complex organic reactions,is a highly desirable yet challenging endeavor.Meanwhile,identifying the active site also represents a significant obstacle,primarily due to the intricate electronic environment of single atom site doped metal oxide.Herein,a single atom Cu doped TiO_(2)catalyst(Cu_(1)-TiO_(2)) is prepared via a simple“colloid-acid treatment”strategy,which switches aniline oxidation selectivity of TiO_(2) from azoxybenzene to nitrosobenzene,without using additives or changing solvent,while other metal or nonmetal doped TiO_(2) did not possess.Comprehensive mechanistic investigations and DFT calculations unveil that Ti-O active site is responsible for triggering the aniline to form a new PhNOH intermediate,two PhNOH condense to azoxybenzene over TiO_(2) catalyst.As for Cu_(1)-TiO_(2),the charge-specific distribution between the isolated Cu and TiO_(2) generates unique Cu_(1)-O-Ti hybridization structure with nine catalytic active sites,eight of them make PhNOH take place spontaneous dissociation to produce nitrosobenzene.This work not only unveils a new mechanistic pathway featuring the PhNOH intermediate in aniline oxidation for the first time but also presents a novel approach for constructing single-atom doped metal oxides and exploring their intricate active sites.

Biodegradability of Chlorinated Anilines in Waters

Objective To identify the bacteria tolerating chlorinated anilines and to study the biodegradability of o-chloroaniline and its coexistent compounds. Methods Microbial community of complex bacteria was identified by plate culture observation techniques and Gram stain method. Bacterial growth inhibition test was used to determine the tolerance of complex bacteria to toxicant. Biodegradability of chlorinated anilines was determined using domesticated complex bacteria as an inoculum by shaking-flask test. Results The complex bacteria were identified, consisting of Xanthomonas, Bacillus alcaligenes, Acinetobacter, Pseudomonas, and Actinomycetaceae nocardia. The obtained complex bacteria were more tolerant to o-chloroaniline than mixture bacteria in natural river waters. The effects of exposure concentration and inoculum size on the biodegradability of o-chloroaniline were analyzed, and the biodegradation characteristics of single o-chloroaniline and 2, 4-dichloroaniline were compared with the coexistent compounds. Conclusion The biodegradation rates can be improved by decreasing concentration of compounds and increasing inoculum size of complex bacteria. When o-chloroaniline coexists with aniline, the latter is biodegraded prior to the former, and as a consequence the metabolic efficiency of o-chloroaniline is improved with the increase of aniline concentration. Meanwhile, when o-chloroaniline coexists with 2,4-dichloroaniline, the metabolic efficiency of 2,4-dichloroaniline is markedly improved.

The Synthesis of Symmetrical Azobenzenes from Anilines by Phase Transfer Catalysis

Using galvinoxyl as catalyst, the phase transfer catalyzed method of oxidation of primary amines to symmetrical azobenzenes with a saturated solution of potassium ferricyanide in 2 mom aqueous potassium hydroxide and dichloromethane is described. The reaction has intimate relation with Hammett substituent constants. This report offers an efficient and rapid method to prepare azobenzenes and a possible mechanism is also suggested.

An internal circulation iron-carbon micro-electrolysis reactor for aniline wastewater treatment:Parameter optimization,degradation pathways and mechanism

Aniline is a vital industrial raw material.However,highly-toxic aniline wastewater usually deteriorated effluent quality,posed a threat to human health and ecosystem safety.Therefore,this study reported a novel internal circulation iron-carbon micro-electrolysis(ICE)reactor to treat aniline wastewater.The effects of reaction time,pH,aeration rate and iron-carbon(Fe/C)ratio on the removal rate of aniline and the chemical oxygen demand were investigated using single-factor experiments.This process exhibited high aniline degradation performance of approximately 99.86% under optimal operating conditions(reaction time=20 min,pH=3,aeration rate=0.5 m3·h^(-1),and Fe/C=1:2).Based on the experimental results,the response surface method was applied to optimize the aniline removal rate.The Box–Behnken method was used to obtain the interaction effects of three main factors.The result showed that the reaction time had a dominant effect on the removal rate of aniline.The highest aniline removal rate was obtained at pH of 2,aeration rate of 0.5 m^(3)·h^(-1)and reaction time of 30 min.Under optional experimental conditions,the aniline content of effluent was reduced to 3 mg·L^(-1)and the removal rate was as high as 98.24%,within the 95% confidence interval(97.84%-99.32%)of the predicted values.The solution was treated and the reaction intermediates were identified by high-performance liquid chromatography,ultraviolet-visible spectroscopy,Fourier-transform infrared spectroscopy,gas chromatography-mass spectrometry,and ion chromatography.The main intermediates were phenol,benzoquinone,and carboxylic acid.These were used to propose the potential mechanism of aniline degradation in the ICE reactor.The results obtained in this study provide optimized conditions for the treatment of industrial wastewater containing aniline and can strengthen the understanding of the degradation mechanism of iron-carbon micro-electrolysis.

QSPR Studies on the Octanol/water Partition Coefficient (lgK_(ow)) of Substituted Anilines with 2D and 3D Methods

Octanol/water partition coefficient （Kow） is a crucial property for evaluating the environmental behavior and fate of organic compound. Herein, some quantitative structure-property relationship （QSPR） studies were performed to estimate and predict the lgK ow of substituted anilines. 2D method （multiple linear regression, MLR） and 3D method （comparative molecular field analysis, CoMFA） were applied in this study. Successful 2D and 3D models yielded the correlation coefficient （R2） values of 0.981 and 0.966 and the Leave-One-Out （LOO） cross-validated correlation coefficient （q2） values of 0.933 and 0.820, respectively. The developed models have a highly predictive ability in both internal and external validation. In addition, the results were interpreted in terms of physical and chemical meanings of descriptors and field contribution maps. It showed that the steric and electrostatic properties are the primary factors that govern the lgK ow of substituted anilines. The information obtained from the QSPR models would be helpful to the interpretation of structural features pertinent to the lgK ow of substituted anilines, which may be helpful in estimating the organic compounds＇ potential harm to the environment.

One-Pot Three-Component Synthesis of N-Arylmethyl-4-(7-cyclohepta-1,3,5-trienyl)anilines

We report a one-pot three-component synthesis of N-arylmethyl-4-(7-cyclohepta-1,3,5-trienyl)anilines by using various aromatic imines, tropylium tetrafluoroborate, and sodium tetrahydroborate in the presence of imidazole as activator.

Chemical Enhancement of the Surface Enhanced Raman Scattering Signals of Anilines via Their <i>Ortho</i>-Substituents

While Raman spectroscopy is a useful method for analyzing many organic compounds, it is limited by relatively low sensitivity. Therefore, Surface Enhanced Raman Spectroscopy (SERS) based on the adsorption of organic analytes onto gold or silver nanostructures has been used to enhance the signal of chemicals presented at very low concentrations. Although the plasmonic effect of SERS has been shown to play a large role in signal enhancement, the significance of the chemical effect due to the analyte chemisorption on the gold or silver surface is less well understood. In this study, the role of aniline substituents is examined by probing the SERS intensities of various anilines in silver and gold colloids using a Raman spectrometer with an excitation wavelength of 785 nm. The SERS enhancement factors and detection limits for aniline and its mono- and di-substituted ortho derivatives are determined and compared. Both the steric requirements of chemisorption and the inductive effects of electron-withdrawal due to the substituents affect the signal intensities of various vibrational modes of the amino group and the aromatic ring. The degree of enhancement is also related to the methods for preparing the silver and gold colloids, which are characterized by probing the nanoparticle morphology and its degree of aggregation using transmission electron microscopy (TEM).

Can the Prediction of Intrauterine Insemination Results by Used Aniline Blue Stain (ABS) and Sperm Chromatin Dispersion (SCD) Levels?

Introduction: This study aimed to perform routine seminal fluid analysis, sperm DNA fragmentation, and sperm function tests at the chromatin maturation level and evaluate pregnancy in the patients passing intrauterine insemination before starting Intrauterine Insemination (IUI) method. Materials and Methods: In this prospective study, 111 couples who underwent Intrauterine Insemination (IUI) in unexplained infertility patients were admitted to Al-Farah IVF and assisted reproductive center in Baghdad, Iraq between November 2020 and February 2021 were evaluated. Semen fluid analysis was performed based on (WHO 4th) guiding rules. In addition, Sperm Chromatin Dispersion (halo test) and sperm maturation were performed with Aniline Blue Stain (ABS). Results: Sperm Chromatin Dispersion (SCD) groups were compared in terms of pregnancy outcome;the positive pregnancy rate was found to be above in the normal SCD groups (p = 0.0005). In addition, Aniline Blue Stain (ABS) groups were compared in the terms of pregnancy outcome;the positive pregnancy rate was found to be higher in the normal ABS group (p = 0.017). Conclusion: Our study showed that the use of DNA fragmentation (SCD) and sperm maturation tests (ABS) together with routine semen analysis in intrauterine insemination cases will make a significant contribution to the prediction of Intrauterine Insemination (IUI) increased results. So, these results indicate a defect in the effect of DNA fragmentation on the outcome of intrauterine insemination.

加速老化的无铬鞣革中游离苯胺的FIA-UV法分析

采用流动注射分析-紫外光谱法(FIA-UV),基于苯胺与亚硝酸盐在酸性条件下发生的重氮化反应及其在碱性条件下的偶合显色反应,实现苯胺的有效检测.通过实验参数的优化,确定495 nm为最大吸收波长,建立了苯胺质量浓度在0.002~2.0 mg/L范围内与峰高具有良好线性关系的模型(R^(2)=0.9997),检出限为1.62μg/L,重复性(RSD)为0.71%.该方法在加速老化后皮革萃取液中的应用表现出97.8%~103.8%的加标回收率,相较国标法具有更优的抗干扰能力和更高的检测精度.成功建立的苯胺检测新方法,为无铬鞣革产品的质量控制及环境监测提供了重要的技术支持,有助于提高公共健康和环境保护水平.

Cu_(x)Co_(1-x)Al_(2)O_(4)尖晶石催化合成N-乙基苯胺的研究

以硝酸盐为金属源,NaOH为沉淀剂,采用共沉淀法制备Cu_(x)Co_(1-x)Al_(2)O_(4)(x=1,0.75,0.5,0.25,0)系列尖晶石型催化剂。采用X射线衍射(XRD)、X射线荧光光谱仪(XRF)、X射线光电子能谱仪(XPS)、N 2吸-脱附、扫描电镜(SEM)、NH_(3)^(-)程序升温脱附(NH_(3)^(-)TPD)等技术对催化剂进行表征。以乙醇作为苯胺的烷基化试剂催化合成N-乙基苯胺(N-EA),考察了催化剂元素组成、反应温度、胺醇摩尔比、质量空速、反应压力对N-EA收率的影响。结果表明:Cu 0.75 Co 0.25 Al_(2)O_(4)尖晶石催化合成N-EA的最优工艺条件为反应温度240℃、质量空速1.2h-1、醇胺摩尔比为2.25、反应压力3MPa,此时N-EA收率可达81.56%,选择性高达90.82%。

电化学方法下的聚β-环糊精吸附苯胺特征

聚β-环糊精(聚β-CD)是通过电化学合成法制备的一形状类似β-环糊精(β-CD)锥筒型的β-环糊精聚合物。苯胺是一种危害较大的环境污染物之一,聚β-CD包合吸附苯胺(An)的机制研究对今后聚β-CD去除苯胺具有重要的意义。在298.15~323.15 K的温度范围内,以电聚合法合成的聚β-CD/聚苯胺(PANI)复合材料的荷电量为吸附量,通过6种吸附等温模型(Langmuir、Freundlich、Langmuir-Freundlich、Temkin、Henry和BET)和4种动力学方程(准一级动力学、准二级动力学、颗粒内扩散及Elovich方程)的拟合,考察了聚β-CD包合吸附苯胺过程中的等温模型及其吸附动力学特征。结果显示,在此温度范围内,Langmuir-Freundlich、Temkin等温吸附模型适合描述聚环糊精对苯胺的包合吸附,说明聚β-CD包合苯胺是单分子层与多分子层吸附共存,且其吸附热与温度呈线性关系,吸附热随表面覆盖率增加而下降;准一级动力学模型更适合模拟聚β-CD包合吸附苯胺的反应过程,表明聚β-CD包合吸附苯胺以物理吸附为主,因此聚β-CD可以应用于苯胺的去除。

鸡蛋壳生物炭对Cu(Ⅱ)和苯胺吸附研究

针对印染废水有机物和重金属混合污染物难以有效去除的问题,本研究以鸡蛋壳为原料制备生物炭吸附剂,利用SEM、XRD和BET等方法分析生物炭理化性能,采用响应曲面法优化最佳吸附条件,研究其对苯胺和Cu(Ⅱ)吸附性能和吸附机理。试验结果表明:磁性鸡蛋壳生物炭的比表面积为改性前的3.98倍,孔隙结构及吸附点位得到优化,多方位提升生物炭的吸附性能。pH是最显著影响因素,pH和生物炭投加量的交互作用对Cu(Ⅱ)和苯胺去除率的影响较大,最佳吸附条件为pH=6.0,吸附剂投加量0.015 g/mL,接触时间24 h,生物炭对Cu(Ⅱ)、苯胺吸附容量为2.00、0.97 mg/g。MESBC对污染物的吸附过程是以化学吸附为主的多分子层混合吸附,符合准二级动力学模型和Freundlich吸附等温模型。MESBC具有较好的循环再生稳定性,重复利用次数不宜超过5次。

Catalytic wet oxidation of aniline over Ru catalysts supported on a modified TiO_2

The catalytic wet air oxidation of aniline over Ru catalysts supported on modified Ti 2 （Ti 2, Ti0.9Ce0.1O2, Ti0.9Zr0.1O2） is investigated. A series of characterization techniques are conducted to determine the relationship between the physico-chemical properties and the catalytic performance. As a result of the good metal dispersion and large number of surface oxygen species, the Ru/Ti0.9 Zr0.1O2 catalyst presents the best catalytic activity among the tested samples. The effects of the operating conditions on the reaction are investigated and the optimal reaction conditions are determined. Based on the relationship between the by-products concentration and the reaction time, the reaction path for the catalytic oxidation of aniline is established. Carbonaceous deposits on the surface of the support are known to be the main reason for catalyst deactivation. The catalysts maintain a constant activity even after three consecutive cycles.

Electrochemical oxidation of aniline by a novel Ti/TiO_xH_y/Sb-SnO_2 electrode

Electrochemical oxidation of aniline in aqueous solution was investigated over a novel Ti/TiOxHy/Sb-SnO2 electrode prepared by the electrodeposition method.Scanning electron microscopy,X-ray diffraction,and electrochemical measurements were used to characterize its morphology,crystal structure,and electrochemical properties.Removal of aniline by the Ti/TiOxHy/Sb-SnO2electrode was investigated by ultraviolet-Visible spectroscopy and chemical oxygen demand（COD）analysis under different conditions,including current densities,initial concentrations of aniline,pH values,concentrations of chloride ions,and types of reactor.It was found that a higher current density,a lower initial concentration of aniline,an acidic solution,the presence of chloride ions（0.2wt%NaCl）,and a three-dimensional（3D） reactor promoted the removal efficiency of aniline.Electrochemical degradation of aniline followed pseudo-first-order kinetics.The aniline（200 mL of 100mg·L-（-1）） and COD removal efficiencies reached 100%and 73.5%,respectively,at a current density of 20 mA·cm-（-2）,pH of 7.0,and supporting electrolyte of 0.5 wt%Na2SO4 after 2 h electrolysis in a 3D reactor.These results show that aniline can be significantly removed on the Ti/TiOxHy/Sb-SnO2electrode,which provides an efficient way for elimination of aniline from aqueous solution.

Processing of Aniline Aerofloat Wastewater with SBR System and Its Biodegradation Mechanism

ObjectiveThis study aimed to investigate the biodegradation effect and biodegradation mechanism of aniline aerofloat wastewater. MethodSmall-scale processing of simulated aniline aerofloat wastewater was carried out with SBR （Sequencing Batch Reactor） system; intermediate products in the process were analyzed using high-performance liquid chromatography. ResultAccording to the experimental results, the small-scale process was basically stably operated after 40 days of activation and regulation, leading to relatively ideal degradation effect on aniline aerofloat, the COD removal efficiency reached 64.3% , degradation rate of aniline aerofloat reached 93.4%, which could be applied in the treatment of mine flotation wastewater containing such pollutant. During the degradation process, pH increased from 5.83 to 6.60 and then dropped to 6.17, which might be caused by the thiocyanate ions and aniline generated in the degradation process. Aniline aerofloat mainly produced two preliminary products during the biodegradation process： aniline and a substance that was difficult to be biodegraded under aerobic conditions, which was the main reason for the relatively high COD value in effluent. Furthermore, aniline was eventually biodegraded. ConclusionThis study provided basis for the development of biological treatment of flotation wastewater in China and showed great significance for the improvement of ecological environment around the mines.

污染方式对典型成层土中苯胺迁移转化的影响

苯胺污染场地的治理因其特有的相间转换性质而具有挑战,污染方式对污染物的迁移转化起到关键作用,掌握苯胺在土壤环境中的迁移转化规律,预测不同污染方式对苯胺在上部低渗透、下部高渗透(low permeability zone-high permeability zone,LPZ-HPZ)的典型成层土中迁移转化的风险,对污染场地苯胺的修复方案制定具有指导意义。以贺兰山冲积扇的典型成层土为研究对象,在场地调查的基础上进行吸附/解吸实验和土柱淋滤实验,并根据污染场地条件建立苯胺迁移转化模型,研究土壤类型和污染方式(短期高剂量,1个月泄漏100 kg;长期低剂量,1年泄漏100 kg)对苯胺迁移转化规律的影响。结果表明:①研究区砂土和粉土介质对苯胺的吸附过程符合准二级动力学方程,吸附等温线满足Freundlich等温吸附模型。②TMVOC模型能够较好地模拟不同污染方式下典型成层土中苯胺的迁移转化过程。③相同泄漏量情况下,苯胺在长期低剂量污染方式下迁移更深,证明污染源浓度与迁移深度关系密切。④污染事件发生前期,在短期高剂量的污染方式下97.21%的苯胺以非水相液体(nonaqueous phase liquid,NAPL)相存在,长期低剂量污染方式下NAPL相的占比略低,为93.76%;泄漏后期,两种污染方式下均有99.8%以上的苯胺溶解为液相,并达到相间的动态稳定。⑤苯胺进入地下环境3年后,在长期低剂量的污染方式下率先在LPZHPZ界面发生突破行为,进入高渗透层后苯胺纵向迁移速度增加,对地层更深处造成污染,并且此时相间重分配现象最明显。因此在泄漏发生后应在苯胺进入高渗透介质前及时补救,最晚不应超过泄漏事件发生后3年,且前期修复方案选择着重苯胺的NAPL相修复,后期选择利于液相苯胺修复的方案。

22.4%氟唑菌苯胺种子处理悬浮剂对水稻病害的田间防治效果

为明确22.4%氟唑菌苯胺种子处理悬浮剂防治水稻恶苗病、立枯病、纹枯病的田间药效,确定最佳使用剂量和安全性。以22.4%氟唑菌苯胺种子处理悬浮剂用量分别为8、10、12 mL·kg^(-1)和对照药剂3.5%咯菌精甲霜悬浮剂制剂用量4 mL·kg^(-1),进行田间药效对比试验。结果表明,22.4%氟唑菌苯胺种子处理悬浮剂对水稻恶苗病的田间防治效果为80.55%~92.21%,对水稻立枯病的田间防治效果为82.25%~90.11%,对水稻纹枯病的田间防治效果为78.70%~90.77%,增产率为41.25%~55.12%,均显著优于对照药剂3.5%咯菌精甲霜悬浮剂,且对水稻出苗和生长安全、具有显著的促进生长作用。综上所述,22.4%氟唑菌苯胺种子处理悬浮剂拌种防治水稻病害具有较好的效果,生产上建议制剂用量为8~12 mL·kg^(-1),有效成分用量为1.79~2.69 mL·kg^(-1)。

卤代硝基苯高选择性加氢催化剂研究进展

综述了近年来卤代硝基苯液相催化加氢非均相催化剂的研究进展,包括贵金属催化剂和非贵金属催化剂,并对其抑制脱卤的机理进行了阐述,最后对未来卤代硝基苯催化加氢催化剂的研究进行了展望。

绿色氧化剂催化苯胺氧化偶联反应的研究进展

偶氮苯和氧化偶氮苯类化合物在颜料、光学材料、荧光探针和光电器件等领域具有广泛的应用前景.目前,已发展了不同的催化剂和氧化剂用于苯胺氧化偶联制备偶氮苯及氧化偶氮苯类化合物,其中开发绿色环保的氧化体系一直是该研究领域的热点和难点问题.本文综合评述了分别以双氧水和氧气作为氧化剂时,催化苯胺选择性氧化制备偶氮苯及氧化偶氮苯类化合物的研究进展,同时探讨了苯胺氧化的机理,主要包括亚硝基苯中间体机理与自由基偶联机理.最后,总结了催化剂合成和催化机制方面存在的潜在问题和挑战,并对未来的研究方向进行了展望,从而为相关领域的发展提供借鉴.