不同阳离子Y分子筛上金属络合物的吸附和分解 Ⅱ.Co(CO)_3NO吸附和分解的红外光谱表征

采用红外光谱表征了含不同阳离子的Ｙ分子筛上Ｃｏ（ＣＯ）３ＮＯ的吸附和分解及其和阳离子的作用．结果表明，Ｃｏ（ＣＯ）３ＮＯ吸附后主要形成Ｃｏ（ＣＯ）ｘＮＯ（ｘ＝２，３），并出现热稳定性较高的Ｃｏ（ＮＯ）２＋２．产生Ｃｏ（ＮＯ）２＋２的机制和最终分解产物与分子筛阳离子的性质有关．ＮａＹ上Ｃｏ（ＣＯ）ｘＮＯ歧化产生少量Ｃｏ（ＮＯ）２＋２，分解产物主要为Ｃｏ（０）；ＣｏＹ中Ｃｏ２＋的存在部分避免了Ｃｏ（ＣＯ）ｘＮＯ的歧化，分解得到的Ｃｏ（０）含量较高；ＮｉＹ，尤其ＣｕＹ阳离子和吸附物种发生电子转移，形成ＮＯ＋中间物种，氧化Ｃｏ（０）产生Ｃｏ（ＮＯ）２＋２，分解产物为Ｃｏ（０）和Ｃｏ（Ⅱ）的混合物．     

不同阳离子Y分子筛上金属络合物吸附和分解Ⅱ.Co(CO)3NO吸附和分解和红外光谱表征

采用红外光谱表征了含不同阳离子的Ｙ分子筛上Ｃｏ（ＣＯ）３ＮＯ的吸附和分解及其和阳离子的作用。结果表明，Ｃｏ（ＣＯ）３ＮＯ吸附后主要形成Ｃｏ（ＣＯ）ｘＮＯ（ｘ＝２，３），并出现热稳定性较高的Ｃｏ（ＮＯ）２＾２＋。产生Ｃｏ（ＮＯ）２＾２＋的机制和最终分解产物与分子筛阳离子的性质有关。ＮａＹ上Ｃｏ（ＮＯ）ｘＮＯ歧化产生少量Ｃｏ（ＮＯ）２＾２＋，分解产物主要为Ｃｏ（０）；ＣｏＹ中Ｃｏ＾２＋的存在部分避免了     

铈离子清除超氧物自由基的机理

以光辐照核黄素作为超氧物自由基（Ｏ－２）源，研究了Ｃｅ３＋、Ｃｅ４＋对硝基四氮唑蓝（ＮＢＴ）还原、羟胺氧化的抑制作用和铈离子存在时Ｈ２Ｏ２含量、核黄素光分解、溶解氧消耗的变化以及铈离子价态的变化。从而得知，铈离子可清除Ｏ－２，其机理为：Ｃｅ３＋供给Ｏ－２电子氧化为Ｃｅ４＋，Ｏ－２还原为Ｈ２Ｏ２；Ｃｅ４＋从Ｏ－２获得电子还原为Ｃｅ３＋，Ｏ－２氧化为Ｏ２。所以微量的铈离子可清除大量的Ｏ－２。     

铈离子清除超氧物自由在的机理

以光辐照核黄素作为超氧物自由基（Ｏ２）源，研究了Ｃｅ＾３＋、Ｃｅ＾４＋对硝基四氮唑蓝（ＮＢＴ）还原、羟胺化的抑制作用和铈离子存在时Ｈ２Ｏ２含量、核黄素光分解、溶解氧消耗和变化以及铈离子价态的变化。从而得知，铈离子可清除Ｏ２，其机理为：Ｃｅ＾３＋供给Ｏ２电子氧化为Ｃｅ＾４＋、Ｏ２还原为Ｈ２Ｏ２；Ｃｅ＾４＋从Ｏ２获得电子还原为Ｃｅ＾３＋，Ｏ２氧化为Ｏ２。所以微量的铈离子可清除大量的Ｏ２。     

KI催化H2O2分解实验数据处理方法的改进

ＫＩ催化Ｈ２Ｏ２分解实验数据处理方法的改进李玉生王峰（包头钢铁学院化工系内蒙古０１４０１０）过氧化氢的催化分解反应为：ＫＩ＋Ｈ２Ｏ２＝ＫＩＯ＋Ｈ２Ｏ（慢）ＫＩＯ＝ＫＩ＋１２Ｏ２（快）其速率方程为：ｄｃ（Ｈ２Ｏ２）ｄｔ＝－ｋｃ（Ｈ２Ｏ）积分：ｌｎｃ（Ｈ...     

THEORETICAL STUDIES ON THE INTRINSIC REACTION COORDINATE OF THE REACTION HCO＋HNO_2→HCHO＋NO_2

ＴＨＥＯＲＥＴＩＣＡＬＳＴＵＤＩＥＳＯＮＴＨＥＩＮＴＲＩＮＳＩＣＲＥＡＣＴＩＯＮＣＯＯＲＤＩＮＡＴＥＯＦＴＨＥＲＥＡＣＴＩＯＮＨＣＯ＋ＨＮＯ_２→ＨＣＨＯ＋ＮＯ_２￥ＸｉａｎＹｏｎｇＰＡＮＧ；ＹａｎＷＡＮＧ；ＹｏｎｇＰｉｎｇＹＡＮＧ；ＷｅｎＬｉｎＦＥＮ...     

α－Ti（HPO_4）_2·H_2O的制备方法研究

本文介绍了一种快速制备α－Ｔｉ（ＨＰＯ４）２·Ｈ２Ｏ晶体的新方法，该法以硫酸钛为原料，先制得稳定的Ｔｉ（Ｏ２）ＯＨ（Ｈ２Ｏ）＋４配离子溶液，将其加入磷酸溶液后，加热使Ｔｉ（Ｏ２）ＯＨ（Ｈ２Ｏ）＋４分解，逐步释放出钛与磷酸反应，在２小时内制得α－Ｔｉ（ＨＰＯ４）２·Ｈ２Ｏ。在实验温度１２０－１５５℃范围内，此法几乎不受温度和时间的影响。     

N,N,N'''',N''''-四丁基丙二酰胺萃取铀(VI)的机理

研究了Ｎ,Ｎ,Ｎ’,Ｎ’－四丁基丙二酰胺（ＴＢＭＡ）以甲苯为稀释剂,从硝酸介质中萃取硝酸和铀（Ⅵ）的机理。在该萃取体系中,ＴＢＭＡ和 ＨＮＯ_３形成 ＴＢＭＡ· ＨＮＯ_３,和 Ｕ（Ⅵ）形成为 ＵＯ_２（ＮＯ_３）_２· ３ＴＮＭＡ。借助红外光谱分析,确定了在萃合物中ＮＯ_３~－不参与ＵＯ_２~（２＋）的直接配位,并对萃合物中配体的配位方式进行了讨论。     

α—Ti（HPO4）2·H2O的制备方法研究

本文介绍了一种快速制备α－Ｔｉ（ＨＰＯ４）２·Ｈ２Ｏ晶体的新方法，该法以硫酸钛为原料，先制得稳定的Ｔｉ（Ｏ２）ＯＨ（Ｈ２Ｏ４）４＾＋配离子溶液，将其加入磷酸溶液后，加热使Ｔｉ（Ｏ２）ＯＨ（Ｈ２Ｏ）４＾＋分解，逐步释放出钛与磷酸反应，在２小时内制得α－Ｔｉ（ＨＰＯ４）２·Ｈ２Ｏ。在实验温度１２０－１５５℃范围内，此法几乎不受温度和时间的影响。     

笼形聚偕胺肟树脂的研究HX／ACAO树脂吸附贵金属

氢卤酸、硝酸、硫酸、磷酸和硼酸处理的笼形聚偕胺肟树脂（ＨＸ／Ａ－ＣＡＯ）对Ａｇ＋和等贵金属离子的吸附能力按如下顺序：ＰｄＣｌ４２－：Ｈ３ＢＯ３／ＡＣＡＯ＞ＢＣＡＯ＞Ｈ３ＰＯ４／ＡＣＡＯ＞ＨＩ／ＡＣＡＯ＞Ｈ２ＳＯ４／ＡＣＡＯ＞ＨＣｌ／ＡＣＡＯ＞ＨＮＯ３／ＡＣＡＯ＞ＨＦ／ＡＣＡＯ．ＩｒＣｌ６２－：ＢＣＡＯ＞Ｈ３ＰＯ４／ＡＣＡＯ＞Ｈ３ＢＯ３／ＡＣＡＯ＞ＨＣｌ／ＡＣＡＯ＞ＨＦ／ＡＣＡＯ＞ＨＩ／ＡＣＡＯ＞Ｈ２ＳＯ４／ＡＣＡＯ≥ＨＮＯ３／ＡＣＡＯ．ＰｔＣｌ６２：ＢＣＡＯ＞Ｈ３ＢＯ３／ＡＣＡＯ＞Ｈ２ＳＯ４／ＡＣＡＯ＞ＨＮＯ３／ＡＣＡＯ＞ＨＣｌ／ＡＣＡＯ＞ＨＦ／ＡＣＡＯ＞Ｈ３ＰＯ４／ＡＣＡＯ＞ＨＩ／ＡＣＡＯ．Ａｇ＋：ＢＣＡＯ＞Ｈ３ＢＯ３／ＡＣＡＯ＞ＨＩ／ＡＣＡＯ＞Ｈ２ＳＯ４／ＡＣＡＯ＞ＨＦ／ＡＣＡＯ＞ＨＣｌ／ＡＣＡＯ＞Ｈ３ＰＯ４／ＡＣＡＯ＞ＨＮＯ３／ＡＣＡＯ．ＡｕＣｌ４－：ＢＣＡＯ＞Ｈ３ＢＯ３＞Ｈ３ＰＯ４／ＡＣＡＯ＞ＨＦ／ＡＣＡＯ＞ＨＣｌ／Ａ－ＣＡＯ＞Ｈ２ＳＯ４／ＡＣＡＯ＞ＨＩ／ＡＣＡＯ＞ＨＮＯ３／Ａ－ＣＡＯ．研究了Ｈ３ＢＯ３／ＡＣＡＯ树脂对Ａｇ＋和离子的吸附动力学，讨论了吸附机理．     

硝基氢异构化反应的理论研究

The isomerization of singlet, nitryl hydride (HNO2) has been studied by using ab initio method at MP2 level with 6-31G* basis set. The calculation indicates that the reaction is exothermic by 10.8kJ.mol-1, the energy barrier is 227.9kJ•mol-1, and nitryl hydride is not easily isomerized to trans-HONO.     

355 nm光诱发的水体中HNO2与C6H5Br交叉反应机理

利用激光闪光光解技术研究了有氧、无氧条件下HNO2-C6H5Br-H2O体系的光化学反应. 研究结果表明, HNO2与C6H5Br的光化学反应由HNO2光解产生·OH自由基引发, ·OH与C6H5Br反应生成C6H5Br…OH, 反应速率常数为(8.1±0.7)×109 L·mol-1·s-1. C6H5Br…OH可被HNO2或O2氧化. C6H5Br…OH 与HNO2的二级反应速率常数为(3.0±0.5)×107 L·mol-1·s-1, 比C6H5Br…OH与O2的反应速率常数(4.0±0.6)×108 L·mol-1·s-1小, C6H5Br…OH与O2生成的C6H5Br…OHO2以(2.4±0.1)×104 s-1 的速率单分子衰减. 气相色谱-质谱联用(GC-MS)分析表明, C6H5Br…OH 与HNO2或O2作用可形成多种含硝基的化合物或醌类物质.     

氢化物发生-双通道原子荧光光谱法同时测定茶叶和木耳中硒及汞量

经洗净烘干并磨碎的试样在硝酸中浸泡过夜后在硝酸-高氯酸中消解,蒸发至冒白烟并继续蒸至近干,加入一定量的盐酸微沸1～2min,使硒(Ⅵ)还原为硒(Ⅳ),溶液用盐酸(5+95)定容至50mL。此溶液由载流盐酸(5+95)溶液送入氢化物发生器,与还原剂10g.L-1 KBH4溶液混合并反应生成硒的氢化物,样品中汞则生成原子态汞蒸气。两者由载气引入原子化器,在选定的仪器工作条件下,测定硒及汞的荧光强度。在实际样品中,硒、汞共存的浓度比未超过10,在同时测定中两者之间互不干扰。按所提出的条件测定,硒、汞的质量浓度在1.0～5.0μg.L-1范围内与相应的荧光强度值之间呈线性关系,方法的检出限(3s/k)依次为0.077,0.009 8μg.L-1。对仪器测定精密度做了试验,测得其相对标准偏差(n=7)依次为1.98%,1.31%。     

Optimization and validation of arsenic determination in foods by hydride generation flame atomic absorption spectrometry

A hydride generation flame atomic absorption spectrometric method was developed and optimized to quantitate arsenic (As) in foods. A wet digestion of the samples with HNO3 + H2O2 was performed and excess oxidants were eliminated by addition of hydrochloric acid and urea. As5+ in As3+ was then reduced by potassium iodide. The As3+ solution was analyzed by generation of arsine with sodium tetrahydroborate. As determination ranged from 2.5 to 20 microg/L, with a determination coefficient of 0.997. The limits of detection (LOD) and quantitation (LOQ) were 0.6 and 2.1 microg/L, respectively. The method was validated and good results were obtained for recovery, precision, accuracy, LOD, and LOQ. This method is now used to analyze foods from Rwanda.     

Comparison of four microwave digestion methods for the determination of selenium in fish tissue by using hydride generation atomic absorption spectrometry

Four microwave digestion methods of fish tissue for selenium determination by hydride generation atomic absorption spectrometry were compared, in which potassium hexacyanoferrate(III) was chosen as a masking agent for eliminating matrix interferences. The results showed that the methods employing HNO(3)/H(2)O(2), HNO(3)/K(2)S(2)O(8)/H(2)O(2) and HNO(3)/H(3)PO(4)/H(2)O(2) digestion media were unreliable. However, the decomposition using the digestion media of HNO(3)/H(2)SO(4)/H(2)O(2) enabled adequate digestion of fish tissue and retention of selenium in a state amenable for determination. Therefore, the digestion procedures with HNO(3)/H(2)SO(4)/H(2)O(2) media are proposed for the determination of selenium in fish tissue by hydride generation atomic absorption spectrometry. The recoveries of the spiked samples investigated ranged from 90 to 102%. The result obtained from analyzing the NIES CRM No. 6 mussel was in good agreement with the reference value (reference value: 1.5 mug/g; found: 1.45 +/- 0.05 mug/g). The limit of detection for selenium was 0.03 mug/g dry mass for a 100 mg sample. The contents of selenium in local fish species investigated ranged from 0.49 to 2.90 mug/g, and the relative standard deviation for the determination of selenium was less than 8%.     

Vibrational spectra study of the isomerizational reaction of nitryl hydride.

The vibrational spectral study of the isomerization reaction of nitryl hydride is presented in this paper. The isomerizational reaction includes old bond rupture, new bond formation and electronic transfer in the intramolecule. For the isomerizational reaction, the vibrational modes, the vibrational frequencies and the force constants of the reactant, the transition states and product are analyzed. The relationship and the change among them can confirm the rupture of bond, the formation of bond and the process of electron transfer.     

An investigation of the reactions of H3O+ and O2+ with NO, NO2, N2O and HNO2 in support of selected ion flow tube mass spectrometry

A selected ion flow tube (SIFT) experimental investigation has been carried out of the reactions of H3O+, NO+ and O2+ with NO, NO2, N2O and HNO2, in order to obtain the essential kinetic data for the analyses of these compounds in air using selected ion flow tube mass spectrometry (SIFT-MS). These investigations show that NO+ ions do not react at a significant rate with any of these NOx compounds and that H3O+ ions react only with HNO2 (product ions H2NO2+ (75%) and NO+ (25%)). O2+ ions react with NO (product ion NO+), NO2 (product ion NO2+) and HNO2 (product ions NO+ (75%), NO2+ (25%)), but not with N2O. We conclude that both NO and NO2 can be accurately quantified in air using only O2+ precursor ions and SIFT-MS when HNO2 is not present. However, when HNO2 is present it invariably co-exists with both NO and NO2 and then both H3O+ and O2+ precursor ions are needed to determine the partial pressures of NO, NO2 and HNO2 in the air mixture. We also conclude that currently N2O cannot be analysed in air using SIFT-MS.     

An electron-excessive nitrosyl complex: reactivity of a ligand-centered radical leading to coordinated HNO

The reaction of RuHCl(CO)L(2) (L = P(i)Pr(3)) with NO initially forms a 1:1 adduct, shown by DFT calculations and EPR spectroscopy (including the RuD isotopomer) to contain a bent ( 90 degree angle Ru-N-O = 143.9 degrees ) nitrosyl where the majority of the spin density is on the nitrosyl nitrogen. This radical adduct transforms further to give equimolar RuCl(NO)(CO)L(2) and RuHCl(HNO)(CO)L(2), the latter with hydride trans to the nitroxyl ligand HN=O. This is the first observation of the synthesis of coordinated HNO from NO itself. DFT calculations lead to the proposal that this H-atom transfer is effected by free NO, and the lifetime of RuHCl(HNO)(CO)L(2) is indeed qualitatively dependent on the presence of free NO.     

Thermochemistry for enthalpies and reaction paths of nitrous acid isomers

Recent studies show that nitrous acid, HONO, a significant precursor of the hydroxyl radical in the atmosphere, is formed during the photolysis of nitrogen dioxide in soils. The term nitrous acid is largely used interchangeably in the atmospheric literature, and the analytical methods employed do not often distinguish between the HONO structure (nitrous acid) and HNO₂ (nitryl hydride or isonitrous acid). The objective of this study is to determine the thermochemistry of the HNO₂ isomer, which has not been determined experimentally, and to evaluate its thermal and atmospheric stability relative to HONO. The thermochemistry of these isomers is also needed for reference and internal consistency in the calculation of larger nitrite and nitryl systems. We review, evaluate, and compare the thermochemical properties of several small nitric oxide and hydrogen nitrogen oxide molecules. The enthalpies of HONO and HNO₂ are calculated using computational chemistry with the following methods of analysis for the atomization, isomerization, and work reactions using closed‐ and open‐shell reference molecules. Three high‐level composite methods G3, CBS‐QB3, and CBS‐APNO are used for the computation of enthalpy. The enthalpy of formation, ΔH^o_f(298 K), for HONO is determined as ?18.90 ± 0.05 kcal mol^?1 (?79.08 ± 0.2 kJ mol^?1) and as ?10.90 ± 0.05 kcal mol^?1 (?45.61 ± 0.2 kJ mol^?1) for nitryl hydride (HNO₂), which is significantly higher than values used in recent NO_x combustion mechanisms. H‐NO₂ is the weakest bond in isonitrous acid; but HNO₂ will isomerize to HONO with a similar barrier to the HO? NO bond energy; thus, it also serves as a source of OH in atmospheric chemistry. Kinetics of the isomerization is determined; a potential energy diagram of H/N/O₂ system is presented, and an analysis of the triplet surface is initiated. © 2007 Wiley Periodicals, Inc. Int J Chem Kinet 39: 378–398, 2007     

益智及其种植区土壤中汞含量研究

采用氢化物原子荧光法测定了益智种植区土壤与益智各部位中的痕量汞,比较了HNO3＋HF＋H2O2、HNO3＋HF、HNO3＋HClO43种混酸消解体系的消解效果。结果表明,HNO3＋HF＋H2O2为最佳消解体系;样品加标回收率为93．70％～102．25％;土壤及益智果实、根、茎、叶中汞含量分别为0．3583、0．1632、0．0950、0．0700、0．0747mg·kg^-1,土壤中汞在益智果实、根、茎、叶间的迁移率分别为45．55％、26．51％、19．52％、20．83％,土壤及益智各部位的汞含量均在国家规定标准以内。说明海南益智种植区地理环境良好,未受到汞污染。