电感耦合等离子体原子发射光谱(ICP-AES)法测定铜原矿和尾矿中的多元素

采用盐酸+硝酸+氢氟酸+高氯酸溶解试样,通过样品酸浓度条件、分解条件、共存元素干扰等实验,建立了电感耦合等离子体原子发射光谱法测定铜原矿和尾矿中的铜、铅、锌、镍、钴、镉、镁和锰含量的方法。测定范围:ω(Cu):0.010%~2.50%,ω(Pb):0.005%~1.00%,ω(Zn):0.005%~1.50%,ω(Ni):0.005%~0.05%,ω(Co):0.005%~0.05%,ω(Cd):0.005%~0.015%,ω(Mg):0.010%~8.00%,ω(Mn):0.005%~0.50%。经加标回收实验,各元素的加标回收率为86%~103%(n=3),方法准确、可靠,适用于铜原矿和尾矿的铜、铅、锌、镍、钴、镉、镁和锰量的同时测定。     

电感耦合等离子体原子发射光谱法同时测定锌冶炼酸浸渣中12种元素

建立电感耦合等离子体原子发射光谱(ICP–AES)同时测定锌冶炼酸浸渣中铅、铜、铁、镉、钴、镍、锑、钙、镁、铝、砷、锰12种元素的方法。样品采用硝酸–盐酸–氢氟酸–高氯酸四酸溶解,以体积分数为10%的盐酸–硝酸混合溶液为介质,在优化的实验条件下,用电感耦合等离子体原子发射光谱法测定各元素含量。铜、铅、铁、镉、钴、镍、锑的质量浓度在0.10～50μg/mL范围内,钙、镁、铝、砷、锰的质量浓度在0.10～10μg/mL范围内与光谱强度呈良好的线性关系,相关系数均大于0.999,方法检出限为0.002 1～0.025 5μg/mL。测定结果的相对标准偏差为0.012%～1.87%(n=6),样品加标回收率为99.0%～100.3%。采用该方法测定锌精矿成分分析标准物质和实验室内控样品,测定值与参考值基本一致,相对误差为0.00～3.33%。该方法简单、快速,具有较高的准确度和精密度,适用于锌冶炼酸浸渣样品中多元素同时测定,在锌冶炼行业具有重要的应用价值。     

茶叶中多种元素的ICP-AES测定

利用电感耦合等离子体发射光谱法(ICP—AES),同时测定了茶叶中的磷、锰、钙、镁、铝、铁、钾、锌、钴、镍、铅、铜、钒、锶的含量。采用元素间干扰系数法校正元素之间的光谱干扰。回收率在86％～108％,RSD为0.6％～9.5％,结果令人满意。     

火焰原子吸收光谱法测定丹参及复方丹参注射液中微量元素

用硝酸高氯酸混酸(2．4：1)对丹参及复方丹参注射液进行消化处理，用火焰原子吸收光谱法测定处理溶液中的铜、镉、钙、铁、镁、镍、铅、锌、钴、锰等10种微量元素。回收率为97．0％～103．0％，相对标准偏差为1．8％～4．6％。结果表明，丹参及复方丹参注射液中对人体有益的元素如铁，镁，锌含量丰富，具有很大的使用价值。     

电感耦合等离子体原子吸收光谱法测定木菠萝树叶与树干中12种元素

采用用电感耦合等离子体原子发射光谱法测定了木菠萝树叶与树干中铁、锰、铜、锌、钙、镁、钠、钾、铝、铅、镉和镍等12种元素含量。试样用灰化法处理,其残渣用稀硝酸和过氧化氢溶解。选择硝酸(2+98)溶液作为介质,选择波长为238.204,257.610,327.393,206.200,317.933,285.213,589.592,404.721,396.153,220.353,228.802,221.648 nm 12条谱线依次作为铁、锰、铜、锌、钙、镁、钠、钾、铝、铅、镉和镍的分析线,测得12种元素的检出限(3s)均低于0.100 mg.L-1。方法用于木菠萝树叶和树干试样分析,所得测定值的相对标准偏差(n=6)为0.38%~5.52%。     

电感耦合等离子体原子发射光谱法(ICP-AES)测定高铋铅的杂质元素

采用硝酸+酒石酸溶解试样,电感耦合等离子体原子发射光谱法测定高铋铅中的铜、铁、镍、镉、砷、锑和铋的含量。测定范围: ω(Cu)：0.10%～5.00%,ω(Fe)：0.001%～0.10%,ω(Ni): 0.001%～0.10%,ω(Cd): 0.001%～0.050%,ω(As)：0.50%～7.00%,ω(Sb)：0.50%～5.00%,ω(Bi)：1.00%～7.00%。经加标回收实验,各元素的加标回收率为91.5%~114.6%。该方法准确简单,适用于高铋铅中铜、铁、镍、镉、砷、锑和铋量的同时测定.     

电感耦合等离子体原子发射光谱(ICP-AES)法测定再生锌原料中铜、铅、铁、铟、镉、砷、钙、铝

采用硝酸、盐酸、氢氟酸(氟化氢铵)、高氯酸分解样品,电感耦合等离子体原子发射光谱法测定了再生锌原料中铜、铅、铁、铟、镉、砷、钙、铝的量。其测定范围:ω(Cu):0.01%～0.60%;ω(Pb):0.10%～5.00%;ω(Fe):0.10%～5.00%;ω(In):0.0100%～0.200%;ω(Cd):0.010%～3.00%;ω(As):0.10%～2.00%;ω(Ca):0.10%～10.00%;ω(Al):0.10%～4.00%。各元素的加标回收率为93%～113%。方法准确、快速、可靠,适用于再生锌原料中铜、铅、铁、铟、镉、砷、钙、铝量的同时测定。     

微波消解原子吸收光谱法测定鱼肉中14种金属元素

以微波消解法处理鱼肉样品,用火焰原子吸收光谱法测定鲶鱼、胖头鱼、小黄花鱼、鲫鱼4种鱼肉中的钾、钠、镁、钙、铁、钴、镍、铜、锌、锰、锶、铬、镉和铅元素含量。鱼肉样品以5 mL HNO_3和1 mL H_2O_2在一定的温度和时间下经微波消解处理后,在最佳工作条件下测定以上14种金属元素含量,各元素的加标回收率在95.4%~104.6%之间,检出限为0.001 1~0.012 9μg/mL,标准工作曲线的线性相关系数均大于0.999,该方法测定结果的相对标准偏差为0.71%~4.28%(n=10)。该方法适用于鱼肉中钾、钠、镁、钙、铁、钴、镍、铜、锌、锰、锶、铬、镉和铅14种金属元素的含量测定。     

电感耦合等离子体发射光谱(ICP-OES)法测定铅精矿中9种元素

采用硝酸-盐酸-氢氟酸-高氯酸溶样,优化仪器测定条件及消除干扰元素的条件实验等,建立了电感耦合等离子体发射光谱(ICP-OES)法测定铅精矿中砷、锑、铋、铜、锌、镁、铝、铁、镉的方法。其测定范围ω(As):0.02%~1.50%;ω(Sb):0.01%~10.00%;ω(Bi):0.03%~5.00%;ω(Cu):0.50%~10.00%;ω(Zn):2.00%~10.00%;ω(Mg):0.30%~2.00%;ω(Al):0.50%~3.00%;ω(Fe):5.00%~12.00%;ω(Cd):0.030%~0.20%。经加标回收实验,各元素的加标回收率为90%~104%(n=3)。方法准确、快速、可靠,适用于铅精矿中砷、锑、铋、铜、锌、镁、铝、铁、镉量的同时测定。     

硝酸铅沉淀/ICP-MS法测定高纯铅中18种杂质

通过硝酸铅沉淀分离基体铅、有效富集高纯铅中镁、铝、钙、铁、镍、钴、锰、铜、锌、砷、硒、镉、铟、锡、锑、碲、铊、铋等18种杂质,通过电感耦合等离子体质谱测定高纯铅中18种杂质,测定下限在0.04～0.32μg/mL,加标回收率为80%～108%,测定精密度(RSD)为2.5%～14%。     

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%.     

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.     

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.     

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.     

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.     

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.     

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.