高价锰、铁去除水中新兴有机污染物

新兴有机污染物在水环境中广泛存在,对生态环境和人体健康都有潜在危害,如何去除水环境中的新兴有机污染物成为研究人员日益关心的问题。高价锰、铁,主要指高锰酸钾(Mn(Ⅶ), KMnO₄)、高铁酸钾(Fe(Ⅵ),K₂FeO₄),是两类高效且环境友好的无机水处理药剂,可以高效地去除新兴有机污染物,因而备受人们关注。同时,高价锰、铁在降解新兴有机污染物过程中具有相同或者相近的化学性质和相近的化学行为。当前,关于高价锰、铁氧化降解新兴有机污染物的研究主要集中在构建动力学模型,解析中间价态的锰、铁的作用,阐述与其他物质或工艺联用时可能产生的自由基的作用及其在实际水体中的应用。本文综述并比较了高价锰、铁氧化降解新兴有机污染物的动力学模型、中间价态离子的作用、自由基的作用和在实际水体中的氧化特性。     

金属锰暴露致神经毒性的多组学研究进展

锰是环境重金属污染物之一,长期暴露于金属锰或其无机化合物主要引发锰中毒或亚临床神经功能缺陷。锰暴露诱导的神经毒性对遗传易感性、基因表达调控、代谢稳态的影响机制复杂,涉及多靶点,然而常规机制研究往往只能局限于单一通路。鉴于工作场所和环境中重金属锰的分布日益广泛,需要更明确地界定锰的神经毒性作用网络,实现多靶点预防和治疗。多组学技术及其相关分析可在不同的功能水平上对疾病发生发展进程中的差异化进行描述。综述了基因组学、表观遗传学、转录组学、代谢组学在金属锰暴露致神经毒性中的研究结果,探讨潜在的代表性生物标志物,支持多组学方法的整合应用,构建锰的神经毒性作用网络,并对未来研究方向提出展望。     

流动注射催化动力学光度法测定微量锰

在人体中的微量锰能促进发育,且具有抗癌作用,而锰的摄取,一般来自食物[1],如饮用水、茶叶、大米、豆类等,因此,测定环境样品中锰具有实际的意义[2-4].催化动力学光度法测定微量锰也有许多     

催化动力学光度法测定水中微量锰

１引言研究了锰（Ⅱ）催化亮绿ＳＦ褪色反应的动力学特性。在ＮａＡｃ－ＨＡｃ介质中，锰（Ⅱ）对高碘酸钾氧化该试剂的褪色反应具有强烈催化作用，其褪色反应速率与锰（Ⅱ）的浓度在一定范围内呈良好的线性关系。详细研究了亮绿ＳＦ催化动力学光度法测定微量锰（Ⅱ）的条件，建立了测定微量锰（Ⅱ）的新方法。有关文献中催化动力学光度法测定锰（Ⅱ）的检出限大多为１０－１０ｇ／ｍＬ，本方法的检出限为６．０×１０－１１ｇ／ｍＬ，选择性较好，方法相对标准偏差２．５％，用于测定水样中的锰，结果满意。２实验部分２．１主要试剂和仪器…     

三价锰的性质、产生及环境意义

锰是一种储量丰富、分布广泛、价态丰富(0~+7)的过渡金属。三价锰(Mn(Ⅲ))作为一种中间价态锰,易发生单电子转移反应,且易歧化、不易直接检测,导致其在自然界中的存在和作用曾被长期忽略。近期研究显示,络合态Mn(Ⅲ)在海底孔隙水、沉积物好氧/厌氧交界处等环境中广泛存在并对其中生物化学反应有重要影响;络合态及非络合态Mn(Ⅲ)在实验室研究中先后被发现参与到快速且有效地降解污染物的过程。本文综述了环境中Mn(Ⅲ)的存在形态、生成途径,讨论了配体及生物作用对该过程的影响;介绍了实验室中Mn(Ⅲ)的生成方法;总结了Mn(Ⅲ)的水解、歧化、氧化还原电位等性质;概述了Mn(Ⅲ)的环境意义;分析了将Mn(Ⅲ)应用于水污染控制的可能性;并对该领域未来的发展方向进行了展望。     

健骨胶囊中微量元素对实验大鼠股骨的影响

通过对健骨胶囊及实验大鼠股骨中的微量元素铜、锌、铁、锰的分析，阐述了健骨胶囊中微量元素对实验大鼠股骨中的微量元素铜、锌、铁、锰的影响以及骨质疏松症的改善，具有重要的营养学、药理功效学作用。     

新型污染物的环境质谱技术研究进展

随着科学技术的飞速发展,质谱检测及其联用技术方法正以前所未有的速度、广度和深度全面渗透到环境分析化学中,其在环境监测中的使用已经或正在日常化.近年来,一些高分辨质谱及其与色谱等的联用技术在目标污染物和非目标污染物的同时甄别鉴定和分析中发挥了重要作用,其对于阐明污染物在环境的归趋具有重要意义.本文对质谱技术及其与气相色谱和液相色谱的联用技术在污染物尤其是新型污染物分析中的进展进行了总结,并对高分辨质谱技术的环境应用研究给于关注,对环境质谱技术的发展方向进行了展望.     

碳纳米材料与共存污染物的联合毒性

碳纳米材料(carbon nanomaterials,CNMs)具有广泛的应用,其产量飞速增长,并在纳米产品的消费过程中不可避免地被释放到环境中.环境中的CNMs能够与共存污染物(如有机污染物、重金属和其他纳米颗粒)相互作用,影响彼此的归趋及毒性效应.因此在评价CNMs的环境风险时,CNMs与环境中共存污染物的联合毒性不容忽视.本文首先归纳了CNMs对生物体的直接及间接致毒机制,随后着重探讨了CNMs与有机污染物、重金属等环境污染物的联合毒性,从CNMs与其他污染物的作用方式入手,探究了联合毒性与单一毒性发生差异(增强或抑制)的机制,最后对目前CNMs与共存污染物联合毒性的评价方法、研究水平以及面临的挑战进行了分析和展望,为准确评估并深入理解CNMs的环境风险提供一定的理论基础.     

种植青海大黄中微量元素研究

青海地道中药材“西宁大黄”野生资源濒临枯竭,人工种植规模不断扩大。定期采集青海西宁及邻近地区两年生种植大黄,跟踪分析了其微量无素铜、锌、铁、锰、铬,为地道西宁大黄资源的可持续开发和利用提供科学依据。研究表明,种植大黄中微量元素铁、锌、铜、锰的有效积累以及土壤地球化学环境中的微量元素锌、锰、铜对种植大黄的生长具有重要的作用和意义。     

生物质炭的制备及其在吸附中的应用

农药、重金属、染料、药物、个人护理品等是水体中常见的污染物,其中一些化合物具有毒性高、难分解、残留期长的特点,易随食物链积累,可危害到人类健康.水中污染物的处理工艺有生物降解、化学氧化、膜过滤法、吸附和光催化降解等,其中吸附法操作简单、效率高、毒副产物少,是去除污染物广泛使用的方法.生物质炭具有高比表面积、高孔隙率以及多种官能团,对多种污染物具有良好吸附作用,在吸附污染物的研究中发挥着重要作用.详细介绍了生物质炭的制备方法、性质及其在污染物吸附中的应用.     

二氧化碳和丙烯直接合成甲基丙烯酸的NiPMo/TiO2催化剂的研究

用溶胶-凝胶法以磷钼酸(MPA)的镍盐溶液水解钛酸四丁酯制备了NiPMo/TiO2催化剂.使用ICP、 XRD、 TG-DTA、 IR、 TPD-MS和微反应技术研究了催化剂的化学组成、热稳定性、化学吸附性质和催化反应性能.杂多钼酸盐与TiO2通过O2-在TiO2表面发生了键合.在623 K下,杂多阴离子仍保持原有的Keggin结构.CO2在Lewis酸位Ni(Ⅱ)和Lewis碱位Ni-O-Mo的桥氧协同作用下生成CO2卧式吸附态Ni(Ⅱ)←O-(CO)←(O--Ni).丙烯有多种吸附态在催化剂上吸附.在563 K、 1 MPa和空速1500 h-1的反应条件下,丙烯的摩尔转化率为3.2%,产物MAA选择性为95%.     

CoFe2O4自形成磁性液体场致结构化对磁化的影响

The Langevin paramagnetic theory can’t describe the relation between magnetization of ferrofluids and applied magnetic field. The structuralization of ferrofluids, which is considered the main influence factor of the magnetization, is regarded. The part of magnetization works is deposited when the structure is forming. This action influences the magnetization of ferrofluids directly or indirectly. On the base of the “compressing” model, the Langevin function that usually describes the magnetization of ferrofluid is modified, and a well-fitted curve is obtained. An equation of the relation between the equivalent volume fraction after being “compressed” and the intensity of magnetic field is discovered, which approximately describes the process of magnetization. The relation between the approximate initial susceptibility and the volume fraction can be obtained from modified formula.     

Highly regioselective Buchwald–Hartwig amination at C-2 of 2,4-dichloropyridine enabling a novel approach to 2,4-bisanilinopyridine (BAPyd) libraries

The highly regioselective Buchwald–Hartwig amination at C-2 of the cheap and readily accessible reagent, 2,4-dichloropyridine with a range of anilines and heterocyclic amines is described. This new methodology is robust and provides a facile access to 4-chloro-N-phenylpyridin-2-amines on 0.25 mol scale. These intermediates undergo a further Buchwald–Hartwig amination at higher temperature to enable rapid exploration of the chemical space at C-4 and to provide a library of 2,4-bisaminopyridines.     

Sulfur-directed metal-free and regiospecific methyl C(sp3)–H imidation of thioanisoles

Regiospecific and direct imidation of the methyl C(sp³)–H bond of thioanisoles is realized under mild and metal-free conditions with N-fluorobis(benzenesulfonyl)imide as an oxidant and nitrogen source. Proposed mechanism suggests that thionium ion intermediates and a Pummerer-type reaction are involved. The imidation has advantages such as high step-economy, excellent functionality tolerance, and regiospecificity, giving structurally diverse imidation products.     

Selective syntheses of 2H-1,3-oxazines and 1H-pyrrol-3(2H)-ones via temperature-dependent Rh(II)-carbenoid-mediated 2H-azirine-ring expansion

The Rh(II)-catalyzed reaction of 2-carbonyl-substituted 2H-azirines with ethyl 2-cyano-2-diazoacetate or 2-diazo-3,3,3-trifluoropropionate provides an easy access to 2H-1,3-oxazines and 1H-pyrrol-3(2H)-ones. These compounds can be selectively prepared from the same starting material using temperature as the only varied parameter. The 2-azabuta-1,3-diene intermediate, a common precursor for both heterocyclic products, isomerizes into 2H-1,3-oxazine under kinetic control, while 1H-pyrrol-3(2H)-one is the sole product of the reaction at elevated temperatures. According to DFT-calculations a one-atom oxazine ring contraction involving ring-opening to a 2-azabuta-1,3-diene intermediate, followed by a 1,5- and 1,2-prototropic shift leads to the consecutive formation of imidoylketene and azomethine ylide, which then further undergo cyclization to the pyrrole derivative.     

Copper catalyzed/mediated synthetic methodology for ebselen and related isoselenazolones

Scope of the copper catalyzed/mediated selenium-nitrogen coupling reaction has been studied for the synthesis of isoselenazolones. It is noticed that the 2-chloro, 2-bromo-, and 2-iodo-aryl amides substrates can be exploited in the selenium-nitrogen coupling reaction by employing 25-100 mol % of CuI/1,10-phenanthroline (L) and potassium carbonate as a base in DMF. Furthermore, electron rich 2-chloro-arylamides also underwent selenium-nitrogen coupling reaction to give biologically important selenium-nitrogen heterocycles. Also, copper-catalyzed selenium-nitrogen coupling reaction has been meticulously applied for the synthesis of diaryl diselenides having methoxy, amine, and amide functionality from respective aryl iodides in the presence of stoichiometric amount of succinimide as an external Se-N coupling partner.     

Knoevenagel condensation catalyzed by novel Nmm-based ionic liquids in water

A series of novel N-methyl morpholine (Nmm) based ionic liquids with 1,2-propanediol group were synthesized and used as catalysts for Knoevenagel condensation at room temperature in water. Under the effect of the catalyst, various aldehydes or aliphatic ketones could react with a wide range of activated methylene compounds well, including malononitrile, alkyl cyanoacetate, cyanoacetamide, β-diketone, barbituric acid, 2-arylacetonitrile and thiazolidinedione. Furthermore, most of the products could be separated just by filtrating and washing with water. Additionally, the catalyst is recyclable and applicable for the large-scale synthesis.     

Construction of polyheterocyclic spirotetrahydrothiophene derivatives via sulfa-Michael/aldol cascade reaction

A series of polyheterocyclic spirotetrahydrothiophene derivatives were obtained in moderate to excellent yields via a catalyst-free sulfa-Michael/aldol cascade reaction of chalcones 1 and commercially available 1,4-dithiane-2,5-diol 2 under mild conditions. We also present the first asymmetric sulfa-Michael/aldol cascade reaction of chalcones 1 and commercially available 1,4-dithiane-2,5-diol 2 with moderate to good enantioselectivities catalyzed by readily available chiral phase-transfer catalysts (PTCs).     

Suzuki-Miyaura reactions of the soluble guanylate cyclase inhibitor NS2028: a non-product specific route to C-8 substituted analogues

Both soluble guanylate cyclase (sGC) inhibitors ODQ 1 and NS2028 2 are synthesized via improved protocols. In the former case treating 3,4-dihydroquinoxalin-2(1H)-one oxime 8, which can be prepared in two steps from 1,2-benzenediamine, with 1,1′-carbonyldiimidazole (CDI) gives the dihydro-ODQ 10 that in the presence of KMnO₄ oxidises to give ODQ 1 in an overall yield of 46% starting from 1,2-benzenediamine. In the latter case, the synthesis affords NS2028 2 from 2-amino-4-bromophenol 3 in three steps with an overall yield of 85% and avoids the need for chromatography. Furthermore, Suzuki-Miyaura reaction conditions are described that enable the preparation of 8-aryl and 8-heteroaryl derivatives of NS2028 directly from NS2028 2. Finally, demethylation of the 8-(methoxyphenyl) substituted analogues afforded the 8-(hydroxyphenyl) derivatives 40-42. All new products are fully characterised.