天然沸石粉阳离子吸附性能分析方法的探讨

通过比较不同浓度的NH4Ac溶液对天然沸石粉所吸附的碱金属和碱土金属离子多次连续提取的效果,将由交换性K^ 、Na^ 、Ca^2 和Mg^2 加和所获得的阳离子交换量与由常规土壤阳离子交换量测定法获得的阳离子交换量进行比较,发现常规的土壤分析方法不适于测定天然沸石粉所吸附的交换性K^ 、Na^ 、Ca^2 和Mg^2 及阳离子交换量。建议用K^ 、Na^ 、Ca^2 和Mg^2 5次提取总量分别作为天然沸石粉所吸附的交换性K^ 、Na^ 、Ca^2 和Mg^2 的估算值,并把其提取量加和作为沸石粉阳离子交换量的估算值．     

离子色谱法测定酸雨中的阳离子

用离子色谱法测定酸雨中的Na^ 、NH4^ 、K^ 、Mg^2 、Ca^2 等阳离子，并同时用原子吸收分光光度法进行了对比实验。结果表明，利用离子色谱法测定阳离子，方法简便、快捷，能一次同时测定多种离子，测定结果和原子吸收法相符。     

广西车田红辉沸石对不同离子吸附性的初步研究

研究表明，不同粒度的红辉沸石在不同的温度条件下对K^ 、Na^ 、Ca^2 、Mg^2 、NH4^ 等离子具有不同的吸附容量。在30℃时，8μm的红辉沸石对K^ 、Na^ 、Ca^2 、Mg^2 、NH4^ 的吸附量分别为：10.90mg/g、10.01mg/g、7.64mg/g、5.50mg/g、108.70mmol/100g；45μm的红辉沸石对K^ 、Na^ 、Ca^2 、Mg^2 、NH4^ 的吸附量分别为：10.10mg/g、9.80mg/g、6.90mg/g、5.08mg/g、101.10mmol/100g；246μm的红辉沸石对K^ 、Na^ 、Ca^2 、Mg^2 、NH4^ 的吸附量分别为：2.66mg/g、2.20mg/g、1.86mg/g、1.26mg/g、28.00mmol/100g；在2℃时，8μm的红辉沸石对K^ 、Na^ 、Ca^2 、Mg^2 、NH4^ 的吸附量分别为：10.60mg/g、9.82mg/g、6.90mg/g、5.07mg/g、99.60mmol/100g。在常温25－30℃，湿度82％条件下，246μm、45μm、8μm的红辉沸石含水率为7.06%、7.25%、7.78%。     

啤酒酵母生理代谢过程中钠、钾、镁、钙离子含量变化的跟踪检测

采用空气-乙炔火焰原子吸收光谱法分别测定了啤酒酵母发酵液中的Na^ 、K^ 、Mg^2 、Ca^2 离子动态变化中的含量,用La^3 盐消除P对Ca^3 的干扰,以Sr^2 盐作为Na^ 、K^ 的消电离剂。本实验室采用配制培养基,通过对不同种类及不同发酵阶段培养的发酵液样品进行测定,以研究在啤酒酵母生长代谢过程中Na^ 、K^ 、Mg^2 、Ca^2 离子代谢动态变化。方法的Na^ 、K^ 、Mg^2 、Ca^2 相对标准偏差(RSD)分别为0．31％,0．73％。1．78％,0．28％;样品加标回收率为98％-107％;检出限：Na^ 为0．159mg／L,K^ 为0．789nag／L,Mg^2 为0．039mg／L,Ca^2 为0．029mg／L。该方法简便快速,具有很好的精密度。     

广西车田红辉沸石对不同离子吸附性的初步研究

研究表明,不同粒度的红辉沸石在不同的温度条件下对K^ 、Na^ 、Ca^2 、Mg^2 、NH4^ 等离子具有不同的吸附容量。在30℃时,8μm的红辉沸石对K^ 、Na^ 、Ca^2 、Mg^2 、NH4^ 的吸附量分别为：10.90mg/g、10.01mg/g、7.64mg/g、5.50mg/g、108.70mmol/100g;45μm的红辉沸石对K^ 、Na^ 、Ca^2 、Mg^2 、NH4^ 的吸附量分别为：10.10mg/g、9.80mg/g、6.90mg/g、5.08mg/g、101.10mmol/100g;246μm的红辉沸石对K^ 、Na^ 、Ca^2 、Mg^2 、NH4^ 的吸附量分别为：2.66mg/g、2.20mg/g、1.86mg/g、1.26mg/g、28.00mmol/100g;在2℃时,8μm的红辉沸石对K^ 、Na^ 、Ca^2 、Mg^2 、NH4^ 的吸附量分别为：10.60mg/g、9.82mg/g、6.90mg/g、5.07mg/g、99.60mmol/100g。在常温25-30℃,湿度82%条件下,246μm、45μm、8μm的红辉沸石含水率为7.06%、7.25%、7.78%。     

细胞内游离离子及离子通道的核磁共振研究

生物细胞内游离离子及离：子通道(Ca^2 、Mg^2 、Na^ 、K^ 以及Na^ ／Ca^2 和Na^ ／Li^ 交换等)在生理病理过程中起着重要作用。用于这些方面研究的生物核磁共振方法主要包括有：^31PNMR、^19NMR、^7Li NMR及^23Na NMR等。^31P NMR主要用于对细胞内小分子代谢物、pH及游离Mg^2 的分析测定；^19F NMR是利用氟代指示剂间接地测定细胞内游离Mg^2 和Ca^2 的浓度，进而对钙镁离子通道进行分析研究；^7Li NMR、^23Na NMR等方法分别用于研究Li^ 、Na^ ／Li^ 交换、Mg^2 ／Li^ 交换、Na^ 及K^ 等。为了更好地理解和阐释细胞内离子的调控机制，本文对近几年核磁共振技术在这些方面的应用进行了综述。     

离子色谱法测定浴盐中的阴、阳离子

用离子色谱法测定浴盐中的Na^ 、K^ 、Mg^2 、Ca^2 、Cl^-、Br^-、SO4^2-时，分离阳离子的色谱柱为ICS-C25阳离子交换柱，淋洗液为2.0mmol/L均苯四甲酸溶液，流速为0.6mL/min；分离阴离子时的色谱柱为shim-pack IC-Al阴离子交换柱，淋洗液为2.5mmol/L邻苯二甲酸溶液－2.4mmol/L三羟基氨基甲烷溶液（体积比为1：1），流速为1.0mL/min。所测离子Na^ 、K^ 、Mg^2 、Ca^2 、Cl^-、Br^-、SO4^2-在较宽浓度范围内有良好的线性关系，回收率为94.7%-102.4%，检出限为0.001-0.02mg/L，相对标准偏差为1.03%-1.63%。     

离子色谱法测定水利工程水样中的5种无机阳离子北大核心CSCD

提出新型高通量离子色谱仪快速测定水利工程水样中5种阳离子Na^+、NH_4^+、Mg^(2+)、Ca^(2+)和K^+的含量的方法。采用TSKgel Super IC-CR阳离子交换柱,以2.2 mmol·L^(-1)甲基磺酸和1.00 mmol·L^(-1)18冠醚6的混合液为淋洗液,流量为0.7 mL·min^(-1),柱温为40℃,凝胶抑制电导检测,可在18 min内完成对5种阳离子的分析。5种无机阳离子的质量浓度在一定范围内与其峰面积呈线性关系,Na^+、NH_4^+、Mg^(2+)、Ca^(2+)和K^+的检出限(3S/N)分别为7.1,6.3,9.5,10.0,8.3μg·L^(-1),水样的加标回收率为95.3%~104%,相对标准偏差(n=5)为0.26%~4.0%。     

离子色谱法同时测定水中六种阳离子

研究了用抑制电导离子色谱法一次进样同时测定水中Li^ ,Na^ , NH4^ ,Mg^2 ,Ca^2 的色谱法条件，相对标准偏差小于0．5％，加标回收率在97．5％－104．0％。在水质分析中运用t检验法，比较了用钙、镁离子浓度计算和传统方法测定的总硬度之间是否存在显著性差异。     

内含式化合物X@Al12P12的结构与稳定性研究

采用B3LYP／6—31G*方法,对内含式化合物X@Al12P12(X=Li^0/ ,Na^0/ ,K^0/2 ,Be^0/2 ,Mg^0/2 ,Ca^0/2 ,H和He)的不同对称性构型进行计算,讨论其最稳定构型的几何参数、布居分析、偶极矩、电离势、包含能、频率、HOMO—LUMO能隙和自旋密度．发现X@Al12P12化合物中,客体X=Na^0/ ,K^0/ ,Mg和He几乎处在笼的中心,Be和Ca^0/2 处在中心附近0．033nm的半径内,Li^0/ ,Be^2 ,Mg^2 和H很大程度上偏离笼的中心位置．大部分金属内含式化合物的C3对称性构型稳定．Li^0/ 。,Be^0/2 ,Mg^2 ,Ca^2 和H与其它离子相比更易嵌入笼内形成稳定的内含式化合物．     

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.     

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.     

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.     

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.     

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.     

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.