X射线荧光光谱法测定黏土中的主次组分

采用熔融玻璃片制样,选用标准样品,以经验α系数和散射线内标法校正元素谱线重叠干扰和基体效应,使用ZSX Primus Ⅱ X射线荧光光谱仪对黏土样品中的Al₂O₃、SiO₂、Fe₂O₃、CaO、MgO、K₂O、Na₂O、MnO、P₂O₅、TiO₂、Cu、Cr等组分进行测定,分析结果与标准值和化学值相吻合,12次测定的相对标准偏差小于10%.     

X射线荧光光谱法分析镁砂的主次成分

采用镁砂标准样品作为校准样品,建立了熔融制样X射线荧光光谱法测定镁砂中MgO,Al2O3,SiO2,CaO,P2O5,Fe2O3的方法。采用熔融法为样品片和校准片的制备方法,选择四硼酸锂-偏硼酸锂（67＋33）为助熔剂,1.00mL LiBr溶液为脱模剂,熔融温度为1 100℃,熔融时间20min。对镁砂样品测定的相对标准偏差（RSD）小于3%,对不同镁砂标准样品进行测定,方法的测定结果与认证值相吻合。     

X射线荧光光谱法分析镁砂中的主次成分

采用镁砂标准样品作为校准样品,建立了熔融制样X射线荧光光谱法测定镁砂中MgO,Al2O3,SiO2,CaO,P2O5,Fe2O3的方法。采用熔融法为样品片和校准片的制备方法,选择四硼酸锂-偏硼酸锂(67+33)为助熔剂,1.00mL LiBr溶液为脱模剂,熔融温度为1 100℃,熔融时间20min。对镁砂样品测定的相对标准偏差(RSD)小于3%,对不同镁砂标准样品进行测定,方法的测定结果与认证值相吻合。     

熔融制样-X射线荧光光谱法测定直接还原铁中主次元素含量

应用熔融制样-X射线荧光光谱法测定了直接还原铁中主次元素的含量。样品置于铂金坩埚中,以四硼酸锂和偏硼酸锂为熔剂于1 050℃熔融20min,将熔化的样品倒入铂金模具中,所制得的片样用于X射线荧光光谱分析。以铁矿石标准物质GBW 07221等25种标准物质制作校准曲线,以固定理论α影响系数法校正基体效应。方法用于实际样品的分析,所得结果与其他方法测定值相符。测定值的相对标准偏差(n=10)在0.31%~16%之间。     

熔融制样-X射线荧光光谱法测定火力发电厂烟气脱硫石膏中主次量元素

建立了熔融制样-X射线荧光光谱法(XRFS)测定火力发电厂烟气脱硫石膏中9种主次量元素(以元素氧化物形式表示)的方法,并用正交试验优化了熔融制样条件。将样品与四硼酸锂-偏硼酸锂混合熔剂(质量比12∶22)按1∶8的质量比混合,加入40 g·L~(-1)溴化锂溶液0.6 mL,在自动燃气熔样机上于1 050℃熔融4.5 min,冷却脱模后即得玻璃样片,在优化的XRFS条件下测定。采用硫酸钙、氧化钙、石膏成分分析标准物质和煤灰成分分析标准物质配制的标准样品系列制作校准曲线,并用理论α系数法校正基体效应。结果显示:9种主次量元素氧化物线性相关系数均大于0.990 0,检出限为0.006 4%～0.059 9%。方法用于2个烟气脱硫石膏样品的分析,2次平行测定值的差值均小于国家标准GB/T 5484-2012规定的重复性限,且测定值和GB/T 5484-2012的基本一致。     

熔融制样-X射线荧光光谱法测定铁矿石中钾、铅、锌和砷

采用熔融制样-X射线荧光光谱法测定铁矿石中钾、铅、锌和砷的含量。样品以四硼酸锂和碳酸锂为熔剂,在1 050℃下熔融20min,冷却后制成玻璃融片,用于X射线荧光光谱分析,以标准物质制作校准曲线。方法应用于铁矿石标准样品(GSB 1805-2005)的测定,测定值与认定值相符,测定值的相对标准偏差(n=10)在2.0%~4.5%之间。     

X射线荧光光谱法测定钒铁合金中主次元素含量

用熔融制样法将钒铁合金样品在铂金坩埚中与四硼酸锂和偏硼酸锂熔融,熔体在铂金坩埚中自动成型,用X射线荧光光谱法测定钒铁合金中钒、硅、锰、铝和磷等主次元素含量。经试验求得熔融时,四硼酸锂、混合溶剂(四硼酸锂∶偏硼酸锂=67∶33)和样品的最佳质量比为30比5比1。各元素的检出限在12.4～51.2μg.g-1之间。方法用于标准样品分析,测定值与认定值相符。     

X-射线荧光光谱法测定锆矿石中锆硅铁钛铝钙

采用熔片法制样,建立了X-射线荧光测定锆矿石中锆、硅、铁、钛、铝、钙的分析方法。使用国家一级标准物质与二氧化锆混合配制的混合标准物质,解决了锆矿石标准物质不足的问题。试样:硼酸锂混合熔剂为1:20,在熔样机中熔成玻璃片,采用经验系数法和散射线内标法校正元素间的谱线重叠效应和基体效应,对标准物质和混配的标准样品进行了分析,标准物质测定结果与推荐值一致,相对标准偏差（RSD%）均小于3.6%。方法能满足高含量锆矿石中主、次量元素的测定。     

电感耦合等离子体质谱(ICP-MS)法测定锆钛矿中的铪

锆钛矿组成成分复杂,存在耐高温的锆、钛化合物,不易分解,且铪以类质同象进入锆矿物,导致锆钛矿中的铪含量不均,因此完全分解锆钛矿并准确测定其中含量不同的铪成为一个难题。本文建立了碳酸钠-硼砂高温熔融,以178Hf为分析同位素及50 ng/mL185Re为内标,使用电感耦合等离子体质谱法（ICP-MS）测定锆钛矿中铪的新方法,可准确锆钛矿中含量不均的铪。实验研究了锆钛矿成分及其熔融方法,结果表明碳酸钠-硼砂高温熔融效果最好,可完全溶解耐高温难分解的锆钛矿,当碳酸钠-硼砂质量配比为2:1时熔融效果最佳。电感耦合等离子体质谱法具有检出限低、灵敏度高、线性范围宽等优势,可用于测定锆钛矿中含量不均的铪,ICP-MS蠕动泵转速为45 rpm、雾化流量为1.06 L/min时雾化效率最优。在选定的实验条件下,HfO2质谱强度与其质量浓度在0.01～250 ng/mL范围内呈良好的线性关系,相关系数为0.9997,背景等效浓度为0.029 ng/mL,方法检出限为0.0032 ng/mL。按实验方法对中国国家标准物质中的HfO2进行测定,测定值与认定值一致,相对标准偏差在1.6%~3.2%之间。按实验方法对锆钛矿样品中的HfO2进行测定并进行加标回收率实验,测定结果的相对标准偏差（RSDs,n=9）在0.9～3.4%之间,加标回收率在96%～106%之间,满足国家地质矿产行业标准DZ/T 0130—2006的要求。     

X-射线荧光光谱法分析硅质耐火材料的主次成分

采用硅石标准样品作为校准样品,建立了熔融制样X-射线荧光光谱法测定硅质耐火材料中SiO2、Al2O3、CaO、MgO、P2O5、Fe2O3、TiO2、K2O、Na2O的方法.采用熔融法为样品片和校准片的制备方法,选择四硼酸锂-偏硼酸锂(质量比为67∶33)为助熔剂,1.00mL LiBr溶液为脱模剂,熔融温度1100℃...     

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.