聚酰胺和负载聚酰胺树脂富集分离环境水中无机汞

提出以聚酰胺、负载双硫腙聚酰胺、负载α-巯基苯并噻唑聚酰胺树脂为吸附剂,在静态和动态条件下,对环境水中无机汞的选择性吸附分离方法.实验表明,此3种树脂在0.1～2.5mol/L HCI介质中,对无机汞吸附性能很好,饱和吸附容量分别为:聚酰胺树脂12.28mg/g;负载双硫腙聚酰胺树脂14.48mg/g;负载α-巯基苯并噻唑聚酰胺树脂17.17mg/g.吸附到各树脂中的汞可用1%～5%硫脲溶液解脱,以冷原子吸收法测定,得到较满意的结果.     

聚酰胺和负载聚酰胺树脂富集分离环境中无机汞

提出了以聚酰胺、负载双硫腙聚酰胺、负载ｎ－巯基苯并噻唑聚酰胺树脂为吸附剂，在静戍 动态条件下，对环境水中无机汞的选择性吸附分离方法。实验表明，此３对脂在０．１￣２．５ｍｏｌ／ＬＨＣｌ介质中，对无机汞吸附性能很好，饱和吸附容量分别为：聚酰胺树脂１２．２８ｍｇ／ｇ；负载双硫腙聚酰胺树１４．４８ｍｇ／ｇ；负载ａ－巯基苯并噻咪聚酰胺 脂１７．１７ｍｇ／ｇ，吸附到各树脂中的汞可用１－５％硫脲溶液解脱，以冷原     

改性聚酰胺负载丁二肟吸附富集原子吸收光谱法测定水中镍

研究了负载丁二肟的改性聚酰胺对镍的吸附和富集行为,确立了负载丁二肟的改性聚酰胺对镍的吸附洗脱条件,建立了负载丁二肟改性聚酰胺对镍富集、分离原子吸收光谱测定的分析方法。结果表明,在pH10的碱性条件下,负载丁二肟的改性聚酰胺对镍有较好的吸附行为,其吸附容量为0．5mg／g;用5mL0．6mol／L的硝酸作为洗脱液,洗脱率可达到100％;负载丁二肟的改性聚酰胺可重复使用三次,吸附率仍可高达到95％以上;方法的富集倍率为80倍;通过对地表水的测定结果令人满意。     

双硫腙螯合型树脂同时分离富集-火焰原子吸收光谱法测定痕量铅和镉

以大孔聚苯乙烯树脂为母体,通过-N=N-,与双硫腙键合,合成了双硫腙螯合型树脂,并将其应用于痕量铅和镉的同时分离富集,实验了酸度、流速、共存离子干扰等因素对双硫腙螯合型树脂吸附和洗脱Pb和Cd的影响,建立了双硫腙螯合型树脂同时分离富集-火焰原子吸收光度法测定食品及环境样品中痕量Pb和Cd的方法.对Pb和Cd,方法的检出限分别为0.015和0.0013μg/mL,相对标准偏差(RSD)均优于3.0%.     

负载α-巯基苯并噻唑聚酰胺树脂富集分离水中汞

提出以合成的纤维状负载α－巯基苯并噻唑聚酰胺树脂为吸附剂,在表态和动态操作条件下,对环境水体中汞的选择性吸附分离方法。实验表明,树脂在pH9的弱碱至2mol/L的强酸介质中,对汞的吸附性能很好,饱和吸附容量为38．74mg/g。树脂中的汞用5％硫脲溶液解脱,再以冷原子吸收分光光度法测定,可对不同水样进行分析,结果满意。     

新型深度除氟改性树脂的制备及其吸附性能研究

以XAD-4为母体自合成了氨基改性和氨基改性后负载金属两种新型深度除氟树脂,并对其进行了理化结构的表征,研究了其吸附特性。结果表明,静态实验中氨基改性的树脂吸附量大于氨基改性并负载金属的树脂。pH值对两种树脂吸附F-的影响均不大。氨基改性的树脂对F-的吸附主要是物理吸附,而氨基改性并负载金属的树脂对F-的吸附主要是化学吸附。两种树脂对F-的吸附均显示出对准二级动力学方程拟合相关性较好。动态实验中,以F-浓度达到1mg/L为穿透点时,氨基改性树脂和氨基改性并负载金属的树脂穿透时间分别为11h和24h。氨基改性树脂对F-的吸附主要通过静电作用进行,而氨基改性并负载金属的树脂对F-的吸附还包括金属与铁离子的络合作用。     

茜素红S螯合树脂分离富集测定地质样品中的痕量金、铂和钯

用螯合树脂对金属进行分离富集及测定,前人已做了许多有意义的研究^[1～4].曾用含键合S双硫腙(P-D)和脱氢双硫腙(P-DT)功能团的离子交换树脂和螯合树脂分离金和铂族金属^[5],用双硫腙负载树脂分离富集Cu(Ⅱ)^[6]。     

双硫腙修饰有机膨润土吸附富集火焰原子吸收法测定水中痕量的钴

采用十六烷基三甲基溴化铵(CTMAB)对膨润土进行改性,用双硫腙对其表面进行修饰,制备了廉价的新型固态吸附剂。以火焰原子吸收为检测手段,研究了该吸附剂对水中Co(Ⅱ)的吸附性能,建立了双硫腙修饰有机膨润土吸附富集,火焰原子吸收法测定水中痕量Co(Ⅱ)的新方法,结果表明,用CTMAB改性后,双硫腙可牢固地负载于膨润土上,制备的固态吸附剂对水中Co(Ⅱ)具有较强的吸附能力;吸附量受介质的pH值和吸附时间的影响;吸附在双硫腙修饰有机膨润土上的Co(Ⅱ)可用1%的EDTA溶液洗脱。应用于自来水和河水中痕量Co(Ⅱ)的测定,取得令人满意的结果。     

PE(聚乙烯)-双硫腙复膜树脂分离富集原子吸收法测定地质样品中的钯

研究了PE(聚乙烯) 双硫腙复膜树脂的合成及其分离富集样品中钯的条件。于pH2.0的HCl介质中,钯定量吸附在PE(聚乙烯)-双硫腙复膜树脂上,用100g L乙二胺-20g LNaOH溶液洗脱,火焰原子吸收光谱法测定。回收率在94.5%～101%之间。可用于实际地质样品中贵金属的分离富集与测定。     

聚乙烯-双硫腙复膜树脂分离富集/原子吸收法测定地质样品中的痕量金

研究了聚乙烯双硫腙复膜树脂的合成及其分离富集痕量金的条件。于pH为2.0的HCl介质中,金离子被定量吸附在聚乙烯双硫腙复膜树脂上,并可用5%硫脲-0.1 mol/LHCl溶液洗脱,洗脱液用火焰原子吸收光谱法测定,金的回收率在91.5%~99.7%之间。本法可用于地质样品中痕量金的分离富集与测定。     

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%.     

Synthesis of 1-benzyloxypyrazin-2(1H)-one derivatives

Different approaches for the synthesis of 1-benzyloxypyrazin-2(1H)-one derivatives from simple amino acids have been investigated. A library of 33 precursors for the preparation of N-hydroxy pyrazinones was obtained in moderate to good yields.     

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.     

A general and convenient synthesis of 4-(tosylmethyl)semicarbazones and their use in amidoalkylation of hydrogen,heteroatom, and carbon nucleophiles

A general synthesis of previously unknown semicarbazone-based α-amidoalkylating reagents, 4-(tosylmethyl)semicarbazones, has been developed. The synthesis involved three-component condensation of semicarbazones of aliphatic or aromatic aldehydes with the same or other aldehydes and p-toluenesulfinic acid. The scope and limitations of this reaction were investigated. The compounds obtained were demonstrated to be an efficient α-(4-semicarbazono)alkylating agents. They were reacted with H- (sodium borohydride), O- (sodium methylate), S- (sodium phenylthiolate), N- (pyrrolidine, sodium succinimide), P- (trialkyl phosphites), and C-nucleophiles (sodium diethyl malonate) to give the corresponding products of the tosyl group substitution, 4-substituted semicarbazones, including analogues of nitrofurazone. Among the prepared compounds tested in vitro for antibacterial and antifungal activity, three nitrofuryl-containing semicarbazones exhibited high biological activities with minimum inhibitory concentration (MIC) values of 8–32 μg/mL.     

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.     

Synthesis of novel chiral bidentate hydroxyalkyl-N-heterocyclic carbene ligands and their application in palladium-catalyzed Mizoroki–Heck couplings and asymmetric addition of diethylzinc to benzaldehyde

A small library of new chiral bidentate hydroxyalkyl-imidazolium salts 1 is conveniently synthesized on multi-gram scale from inexpensive and commercially available chiral pool amino acids. The corresponding carbenes, generated by deprotonation of imidazolium salts 1, in combination with palladium(II) chloride were tested in the Mizoroki–Heck coupling reaction. The most significant results in terms of yields and reactivities were achieved with low catalyst loading. The catalytic activities of these imidazolium salts were also investigated in the asymmetric addition of diethylzinc to benzaldehyde. The use of MgO nanoparticles as an additive in conjunction with these ligands played a crucial role in increasing the efficiency of these reactions.     

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.     

Facile synthesis of bicyclic 1-arylpyrazol-5-ones

In this Letter, we described a facile method for constructing fused bicyclic 1-arylpyrazol-5-one ring system. We employed various methylene-containing carboxylic acids as the substrates and proved that the pyrazolone ring closure requires activated methylene group in intermediate II. Accordingly, a series of structurally diversified, fused bicyclic 1-arylpyrazol-5-ones was prepared in moderate to high yields using the requisite substrates.