Fenton试剂氧化处理模拟含聚丙烯酰胺污水的研究北大核心CSCD

主要研究了利用Fenton试剂氧化法处理模拟含部分水解聚丙烯酰胺的污水,考察了H2O2浓度、Fe2+浓度、温度、反应时间、pH值等因素对Fenton试剂氧化降解模拟含部分水解聚丙烯酰胺污水的影响。结果表明:H2O2浓度为5.3mmol.L-1、Fe2+浓度为1.44mmol.L-1、温度30℃、反应时间15min、pH值范围3～4时,聚丙烯酰胺的氧化降解效果最好,且在最佳条件下,聚丙烯酰胺和CODCr的去除率分别达到87.61%和82.60%。通过对Fenton氧化降解前后的聚丙烯酰胺样品的红外谱图对比,可以推断出Fenton试剂将侧链的酰胺基氧化成羧基。     

Fenton及Photo-Fenton非均相体系降解有机污染物的研究进展

Fenton及photo-Fenton氧化法是一种有效的应用于环境污染物处理领域的高新氧化技术之一,对Fenton试剂的固定化可以减少铁离子的二次污染,提高催化能力和光利用率,及扩展pH等优势。本文综述了近年来Fenton及photo-Fenton非均相体系氧化降解有机污染物的研究状况。引用文献57篇。     

阻燃剂废水的处理研究

阻燃剂生产过程中产生大量的工业废水,通过对比处理实验研究表明：电解Fenton法是处理阻燃剂生产中产生的高浓度有机废水（CODCr=17108mg／L）的有效方法,它既利用了电氧化、电气浮作用,又利用了Fenton试剂的强氧化作用和化学絮凝作用。其处理废水的条件实验结果表明：pH：2．0～2．6;电流密度10．8～14．3A/dm^2;H2O2初始浓度27～42mmol／L;FeSO4初始质量浓度660～990mg／L;电解5h。CODCr去除率达98．34％,色度去除率达74．19％。色质联用分析显示废水处理后的降解产物是无毒害的醋酸。     

[Mn(salen)]2促进Fenton反应降解苯酚废水的催化特性与机理

研究了席夫碱锰配合物{[Mn(Ⅲ)(salen)(H_2O)]_2(ClO_4)_2,简写为[Mn(salen)]_2,salen=N,N'-二(亚水杨基)-1,2-乙二胺}对Fenton反应降解苯酚的催化作用。通过紫外分析、液相色谱、双倒数作图等方法对反应特性、反应机理进行分析。实验结果表明,[Mn(salen)]_2配合物加入Fenton体系后,可提高Fenton反应降解苯酚的效率。在不同pH体系和过量H_2O_2中,均保持一定降解能力。配合物中锰离子可转变成高价态锰中间体,加速有机物氧化,提高降解效率。加入配合物后,[Mn(salen)]_2-Fenton体系催化反应活化能下降了35.9%。重复利用7次后,[Mn(salen)]_2依然保持60%的催化活性。     

可见光/Fenton光催化降解有机染料

采用Fenton试剂(Fe³⁺/H₂O₂)在可见光条件下(λ＞450nm)光催化降解目标染料化合物罗丹明B(RhodamineB,RhB).在pH＜3.0体系中用可见光照射,能使RhB染料在光敏化作用下有效降解,反应160min后矿化率达到71.8%.采用ESR和溴甲酚绿(Bromocresolgreen,BCG)法跟踪测定活性氧化物种,通过对RhB降解过程的紫外-可见光谱、红外光谱分析及总有机碳量(TOC)跟踪测定,结果表明,Fe³⁺/H₂O₂/RhB体系在可见光照射下主要的活性氧化物种为羟基自由基,能有效地降解RhB.     

羟基自由基对多壁碳纳米管表面和结构的影响

碳纳米管纯化后，使用Fenton试剂产生羟基自由基对碳管进行改性处理，研究羟基自由基对碳管表面和结构的影响，并与碳管的混酸处理结果进行比较。FTIR结果表明：经Fenton试剂化学处理后，碳管表面主要引入羟基和羰基，而混酸能“剪切”碳管，产生大量羧基和羰基等官能团。根据Fenton试剂产生羟基自由基的机理，分析了Fenton试剂处理条件的影响因素，控制反应条件即过氧化氢与亚铁离子物质的量之比保持在10左右，而pH值则维持在3左右，对碳管进行改性处理。依据碳管Fenton试剂处理前后的FTIR谱图变化，初步探讨了羟基自由基与多壁碳纳米管作用的可能机理。机理分析表明，改性后碳管表面的羟基和羰基是羟基自由基对碳管上的不饱和键进行加成氧化的结果。     

柴油在超声波/Cu2+/H2O2中的氧化脱硫

为了实现生产低硫柴油和超低硫柴油的目标，以超声波为外加能源，构筑超声波/类Fenton试剂的柴油氧化脱硫反应体系，考察了水相pH值和超声功率这两个参数对柴油氧化脱硫效果的影响。实验结果表明，当类Fenton试剂的水相pH值为2.00左右时，其脱硫效果较好；无超声波下H2O2、类Fenton试剂、超声波/H2O2及超声波/类Fenton试剂的柴油氧化脱硫反应符合表观一级反应动力学规律。超声波功率的提高对氧化脱硫有明显的促进作用,这主要是由于功率的增加，有助于加速空穴的形成与内爆，从而促进反应的进行。     

液相催化复极性流化床电解槽处理对硝基酚废水

应用液相催化复极性流化床电解槽降解处理对硝基酚废水.溶液中的Fe2+离子与O2在阴极还原生的成H2O2形成了Fenton试剂,实验以对硝基酚为降解底物,考察了槽电压、Fe2+浓度及曝气量对模拟废水对硝基酚及COD去除率的影响.结果显示,在pH=3.0,电压30V,Fe2+浓度500 mg.L-1,曝气量0.4 m3.h-1的条件下,对硝基酚及COD均有较高的去除率.     

阴阳离子双隔膜三室电解槽电渗析处理垃圾渗滤液

采用阴阳离子双隔膜三室电解槽,将电渗析技术与Ｆｅｎｔｏｎ试剂法结合,去除垃圾渗滤液中氨氮和ＣＯＤ_Ｃｒ。垃圾渗滤液中的氨氮通过电渗析技术富集到阴极液中,随后用化学沉淀法加以去除。同时,在铁阳极上生成的Ｆｅ^２＋离子,与滴加入阳极液中的Ｈ_２Ｏ_２反应生成Ｆｅｎｔｏｎ试剂,降解有机物,降低ＣＯＤ_Ｃｒ。实验结果表明,模拟废水中的氨氮透过率达８０％,垃圾渗滤液中氨氮浓度和ＣＯＤ_Ｃｒ由原来的１９８２和２２４８ ｍｇ／Ｌ分别降至２００和１２７ ｍｇ／Ｌ。     

Fenton试剂预处理溶出伏安法测定印染废水中的铅

差分脉冲溶出伏安法(DPSV)是测定痕量金属离子的一种高灵敏度的电化学方法。然而,用DPSV测定印染废水中的痕量Pb时,其中的某些成分会富集在电极表面造成汞膜中毒,导致灵敏度降低。因此,常用消解来减少这些组分对DPSV分析测定的干扰。但消解过程易引入污染,且操作费时费力。Fenton试剂可降解难氧化有机污染物,应用于DPSV分析,能显著降低底液中有机物在电极表面的吸附,提高DPSV法的灵敏度和准确度。     

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%.     

Toward new camptothecins. Part 6: Synthesis of crucial ketones and their use in Friedländer reaction

In the context of the preparation of camptothecin and luotonin A analogs, the synthesis of some key keto-precursors and their use in Friedländer condensation are described. This paper also focuses on the stability of these keto intermediates and emphasizes the major differences between indolizinones and pyrroloquinazolinones series. Noteworthy is also the report of some original structures isolated as by-products of some experiments.     

α-Amino acid derived enaminones and their application in the synthesis of N-protected methyl 5-substituted-4-hydroxypyrrole-3-carboxylates and other heterocycles

A new and simple synthesis of novel N-protected methyl 5-substituted-4-hydroxypyrrole-3-carboxylates, which exist in equilibrium with their 4-oxo tautomers, has been developed in two steps starting from N-protected α-amino acids. The key intermediates are enaminones, which can also be isolated, characterized, and used for the construction of other functionalized heterocycles, before they spontaneously decompose to pyrrole products. 4-Hydroxypyrroles are prone to partial aerial oxidation but can be efficiently alkylated or reduced to stable polysubstituted pyrrolidine derivatives.     

Specific intramolecular aromatic CH insertion of diazosulfonamides

The chemoselectivity in the intramolecular CH insertion of various diazosulfonamides has been experimentally studied. The results reveal that the aliphatic 1,4-, 1,5-, or 1,6-C(sp³)?H insertions of diazosulfonamides are not accessible, while the aromatic 1,5-C(sp²)?H insertion can be realized specifically by adjusting the diazo-adjacent group. In addition, the general chemoselectivities in the intramolecular CH insertions of diazosulfonyl compounds are summarized. Generally, diazosulfones undergo both aromatic 1,5-C(sp²)?H and aliphatic 1,5- and 1,6-C(sp³)?H insertions, while diazosulfonates undergo aliphatic 1,5- and 1,6-C(sp³)?H insertions. However, diazosulfonamides only undergo aromatic 1,5-C(sp²)?H insertion.     

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.     

KMnO4-mediated oxidative CN bond cleavage of tertiary amines: Synthesis of amides and sulfonamides

KMnO₄-mediated oxidative CN bond cleavage of tertiary amines producing secondary amine was introduced, which was trapped by electrophiles (acyl chloride and sulfonyl chloride) to form amides and sulfonamides. The reaction could take place at mild condition, tolerating a wide range of function groups and affording products in moderate to excellent yields.     

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.     

Chemistry of heterocyclic compounds at the A. E. Favorsky Irkutsk Institute of Chemistry, Siberian Branch of the Russian Academy of Sciences, over 50 years (Review)

The review contains a concise historical account and information on the most significant researches undertaken by the staff at the A. E. Favorsky Irkutsk Institute of Chemistry, Siberian Branch of the Russian Academy of Sciences on the Chemistry of Heterocyclic Compounds. Dedicated to Academician of the Russian Academy of Sciences B. A. Trofimov on his 70th jubilee. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1443–1502, October, 2008.     

N-Heterocyclic carbene-palladacyclic complexes: synthesis,characterization and their applications in the C-N coupling and α-arylation of ketones using aryl chlorides

N-Heterocyclic carbene-palladacyclic complexes 3 were successfully achieved in a one-pot procedure under mild conditions. The structure of 3a was unambiguously confirmed by X-ray single crystal diffraction and it was an active catalyst in the Buchwald-Hartwig amination and α-arylation of ketones even at very low catalyst loadings (0.01?mol%).     

Iodine-mediated oxidative Pictet-Spengler reaction using terminal alkyne as the 2-oxoaldehyde surrogate for the synthesis of 1-aroyl-β-carbolines and fused-nitrogen heterocycles

An efficient iodine-mediated oxidative Pictet-Spengler reaction in dimethyl sulphoxide (DMSO) using terminal alkynes as the 2-oxoaldehyde surrogate for the synthesis of aryl (9H-pyrido[3,4-b]indol-1-yl)methanones is described. The scope of the protocol includes the total synthesis of Fascaplysin, Eudistomins Y₁ and Y₂. The methodology is extended for preparing pyrrolo[1,2-a]-quinoxaline and indolo[1,5-a]quinoxaline derivatives. The utility of 1-aroyl-β-carbolines was demonstrated by performing palladium-catalyzed β-carboline directed ortho-C(sp2)-H functionalization of the phenyl ring with thiomethyl (SMe) group using DMSO as source and for accessing 4-aryl-canthin-6-ones.