合成CFC-12替代物HFC-134a用CrF3/AlF3催化剂的研究Ⅳ.AlF3基催化剂的制备及性能

本文探讨了γ－ＡｌＦ３的热稳定性和酸性以及活必组分Ｃｒ＾３＋含量与活性的关系，考察了研制的ＡｌＦ３基催化剂的活性，稳定性及再生性，并对催化剂反应前后的结构进行比较，结果表明，催化剂的强酸中心是ＨＣＦＣ－１３３ａ氟化生成ＨＦＣ－１３４ａ的活性中心，催化剂晶格的氟离子参与了氟氯交换反应，ＡｌＦ３基催化剂具有高的活性和稳定性，在３５０℃，经２４００ｈ连续运行后，催化剂的晶相结构及比表面积未发生明显的变化     

合成CFC-12替代物HFC-134a用CrF_3/AlF_3催化剂的研究 Ⅳ.AlF3基催化剂的制备及性能

本文探讨了γＡｌＦ３的热稳定性和酸性以及活性组分Ｃｒ３＋含量与活性的关系．考察了研制的ＡｌＦ３基催化剂的活性、稳定性及再生性，并对催化剂反应前后的结构进行比较．结果表明，催化剂的强酸中心是ＨＣＦＣ１３３ａ氟化生成ＨＦＣ１３４ａ的活性中心，催化剂晶格的氟离子参与了氟氯交换反应．ＡｌＦ３基催化剂具有高的活性和稳定性，在３５０℃，经２４００ｈ连续运行后，催化剂的晶相结构及比表面积未发生明显的变化．催化剂有较高的热稳定性，在４００℃反应８００ｈ催化剂仍具有一定的活性（３０％）．催化剂结炭失活可在３５０℃通空气或空气与ＨＦ的混合气进行再生     

合成CFC-12替代物HFC-134a的CrF_3/AlF_3催化剂研究(Ⅴ)──CrF_3与AlF_3的相互作用

由于氟氯烃（ＣＦＣｓ）对大气臭氧层的破坏作用，使得开发ＣＦＣｓ无污染替代品的研究成为热门课题［１～４］．氢氟烃（ＨＦＣｓ，如ＨＦＣ－１３４ａ）是ＣＦＣｓ的理想替代物．在氟氯交换合成ＨＦＣ－１３４ａ的反应中，ＡｌＦ３基催化剂的活性、稳定性明显优于ＣｒＦ...     

含硫杂核原子簇CpWFeCo(CO)_8(μ_3-S)和(CpW)_2Fe(CO)_7(μ_3-S)的合成及结构研究

本文利用过渡金属的亲硫性，通过Ｃｐ＊－Ｗ（ＣＯ）３Ｃｌ（Ｃｐ＊＝Ｃ５Ｈ５，Ｃ５Ｈ４ＣＨ３）与ＨＦｅ２Ｃｏ（ＣＯ）９（μ３－Ｓ）反应，得到四种含硫异核金属羰基原子簇化合物Ｃｐ＊ＷＦｅＣｏ（ＣＯ）８（μ３－Ｓ）（Ｃｐ＊＝Ｃ５Ｈ５，Ⅰ－ａ；Ｃｐ＊＝Ｃ５Ｈ４ＣＨ３，Ⅱ－ａ），（Ｃｐ＊Ｗ）２Ｆｅ（ＣＯ）７（μ３－Ｓ）（Ｃｐ＊＝Ｃ５Ｈ５，Ⅰ－ｂ；Ｃｐ＊＝Ｃ５Ｈ４ＣＨ３，Ⅱ－ｂ）。对合成的簇合物进行了ＩＲ，１Ｈ／１３Ｃ－ＮＭＲ，Ｃ／Ｈ及金属分析，并对Ⅰ－ａ进行了Ｘ－射线单晶结构分析。     

甲烷氧化偶联制乙烯La2O3—BaO体系催化剂稳定性的研究

研究了甲烷氧化偶联制乙烯高选择性Ｌａ２Ｏ３－ＢａＯ体系催化剂的稳定性．在８００℃、ＣＨ４空速１００００ｈ－１、ＣＨ４／Ｏ２＝８．０～８．３的条件下，催化剂稳定运转了５００ｈ，ＣＨ４转化率和Ｃ２选择性分别为≥１８％和≥８０％．ＸＲＤ和ＸＰＳ分析表明，该催化剂物相稳定，表面Ｌａ／Ｂａ原子浓度之比随反应时间的增加而稍有增加，有利于催化剂活性和选择性的稳定．     

CO2在Ag—Ba—Ca—K／α—Al2O3上的吸附及其在乙烯环氧化反应中的抑制作用

应用ＦＴＩＲ和脉冲反应技术研究了ＣＯ２和Ｏ２在Ａｇ－Ｂａ－Ｃａ－Ｋ／α－Ａｌ２Ｏ３上的吸附及ＣＯ２对Ｃ２Ｈ４环氧化，完全氧化及环氧乙烷（ＥＯ）深度氧化反应的影响。研究结果表明，ＣＯ２和表面吸附氧在负载银催化剂表面存在竞争吸附，ＣＯ２对表面吸附氧有置换作用，该作用降低了银催化剂表面吸附氧的浓度，并且所形成的碳酸根物种改善了乙烯环氧化反应活性氧种的表面分布，对Ｃ２Ｈ４的环氧化反应有一定的抑制作用，但是     

卡宾与醚C—H键插入反应的理论研究（Ⅲ）：CX（X=H,F,Cl）与甲乙醚C—H键插入反

用量子化学从头计算方法在ＭＰ２／６－３１Ｇ（ｇ）水平上研究了ＣＸ２（Ｘ＝Ｈ，Ｆ，Ｃｌ）与甲乙醚的Ｃ－Ｈ键插入反应，在甲乙醚的３个不同的Ｃ－Ｈ键（即甲基中ａ′－Ｃ－Ｈ键，乙基中ａ－Ｃ－Ｈ键和β－Ｃ－Ｈ键）上，反应势垒分别为１２３．８，３２．５，１５７．３ｋＪ／ｍｏｌ（Ｘ＝Ｃｌ）和２５４．３，１３０．０．３０４．２ｋＪ／ｍｏｌ（Ｘ＝Ｆ）。亚甲基与毗邻氧原子的各Ｃ－Ｈ键插入反应没有势垒，与乙基中β－Ｃ－Ｈ键插入势垒仅３．４ｋＪ／ｍｏｌ．甲乙醚中乙基α－Ｃ上的Ｃ－Ｈ键最有利于ＣＸ２的插入，甲基上的Ｃ－Ｈ键次之，乙基β－Ｃ上的又次之。     

SURFACE STUDIES ON A YBa_2Cu_3O_(6～7) CATALYST FOR CO_2 HYDROGENATION TO METHANOL

研究了ＹＢａ２Ｃｕ３Ｏ６～７超导催化剂上ＣＯ２的加氢反应。应用ＴＰＤ、ＴＰＲ、ＳＥＭ和原位ＦＴＩＲ等技术对催化剂进行表征发现，ＣＯ２极易吸附到ＹＢａ２Ｃｕ３Ｏ６～７催化剂的氧空位上。反应过的催化剂易被还原。反应的中间物种是醛基和甲酸根。根据ＦＴＩＲ结果提出甲醇是ＣＯ２和Ｈ２反应的直接产物，ＣＯ２＋Ｈ２→ＣＨ３ＯＨ＋Ｈ２Ｏ和ＣＯ２＋Ｈ２→ＣＯ＋Ｈ２Ｏ是体系中存在的平行反应     

CO_2在Ag－Ba－Ca－K／α－Al_2O_3上的吸附及其在乙烯环氧化反应

应用ＦＴＩＲ和脉冲反应技术研究了ＣＯ_２和Ｏ_２在Ａｇ－Ｂａ－Ｃａ－Ｋ／α－Ａｌ２Ｏ３上的吸附及ＣＯ２对Ｃ２Ｈ４环氧化、完全氧化及环氧乙烷（ＥＯ）深度氧化反应的影响．研究结果表明，ＣＯ２和表面吸附氧在负载银催化剂表面存在竞争吸附，ＣＯ２对表面吸附氧有置换作用，该作用降低了银催化剂表面吸附氧的浓度，并且所形成的碳酸根物种改善了乙烯环氧化反应活住氧种的表面分布，对Ｃ_２Ｈ_４的环氧化反应有一定的抑制作用，但是对Ｃ２Ｈ４和ＥＯ的深度氧化反应的抑制作用更强，使得乙烯环氧化反应的选择性得到改善．     

甲烷氧化偶联MgO／BaCO3催化剂的表面结构与催化活性

用ＣＯ２－ＴＰＤ，ＣＯ，ＣＨ４脉冲以及ＥＰＲ，ＸＰＳ等方法对ＭｇＯ／ＢａＣＯ３的表面结构及催化活性进行研究，结果表明，催化剂的碱性，氧扩散速率等对催化剂的活性均有影响。ＢａＣＯ３和ＭｇＯ的共同作用可以增强催化剂的碱性强度?增加强碱中心的量，调变晶格氧的移动性，提高Ｃ２烃的收率和选择性。ＥＰＲ和ＸＰＳ测试结果表明，表面吸附态的氧物种Ｏ＾－２作为甲烷氧化偶联活性氧物种的前驱态在反应反应条件下可转化为活     

Determination of fluoride in drinking water and in urine of adolescents living in three counties in Northern Chihuahua Mexico using a fluoride ion selective electrode

This study was carried out to determine fluoride in drinking water and in urine of adolescents, ages 15-20 years, living in Northern Chihuahua Mexico. Participants are from a cross-sectional study on health effects of chronic fluoride exposure from drinking water. A total of 201 participants (106 female and 95 male) in the study were recruited from three counties. Samples of drinking water of each county were collected and analyzed using the U.S. EPA Fluoride Ion-Selective Method. Statistically significant difference of fluoride content in water was found among the three counties of recruitment (Cd. Juarez; 0.3 mg/L, Samalayuca, 1.0 mg/L, and Villa Ahumada, 5.3 mg/L). Fluoride content in wells and tap water samples of Villa Ahumada ranged from 5.0 to 5.7 mg/L. Fluoride content of these samples was above the level permitted by Mexican regulations. The fluoride content in bottled water obtained from local stores in Villa Ahumada ranged from 0.3 to 3.7 mg/l.Fluoride in urine samples of each participant was also analyzed using the U.S. EPA Ion-Selective Method. The mean fluoride urine concentration (reported in mg/g creatinine) in adolescents living in these counties was 0.792±0.39, 1.33±0.67 and 2.22±1.16 (Cd. Juarez, Samalayuca and Villa Ahumada), respectively. The high fluoride urinary levels found in participants from Villa Ahumada may be associated to the high fluoride level (5.3 mg/L) in dinking water.The accuracy of measurements was assessed with reference materials in water and in urine. Mean fluoride recovery was 99.0% and 99.6% in water and in urine, respectively. The levels obtained were within the assayed 5% confidence levels.     

Preparation of a new solid state fluoride ion selective electrode and application

A new solid state fluoride ion selective electrode composed of 70% Ag₂S, 10% Cu₂S and 20% CaF₂ has been developed. An analytically useful potential change occurred, from 1 × 10⁻⁶ to 1 × 10⁻¹ M fluoride ion. The slope of the linear portion (1 × 10⁻¹-1 × 10⁻⁵ M) was about 26 ± 2 mV/10-fold concentration changes in fluoride. It was found that pH change between 1 and 8 had no effect on the potential of the electrode. There was no interference of most common cations such as K^+, Na⁺, Ca²⁺ and Mg²⁺ and anions such as Cl⁻, NO₃⁻, SO₄²⁻ and PO₄³⁻. The lifetime of the electrode was more than 2 years, when used at least 4-5 times a day, and the response time was about 60 s.The measurements were made at constant ionic strength (0.1 M NaNO₃) and at room temperature. This electrode has been used for the determination of fluoride ion in Ankara city tap water and in bottled spring water using standard addition method. The validation of the electrode has been made with a commercial fluoride ion selective electrode (Orion) and high consistency was obtained.     

合成CFC-12替代物HFC-134a的CrF_3/AlF_3催化剂的研究 Ⅵ.合成氟代烃的多功能催化剂

合成ＣＦＣ１２替代物ＨＦＣ１３４ａ的ＣｒＦ３／ＡｌＦ３催化剂的研究Ⅵ．合成氟代烃的多功能催化剂吕剑石磊王振宇李惠黎（西安近代化学研究所，西安７１００６５）彭少逸（中国科学院山西煤炭化学研究所，太原０３０００１）关键词氟化铬，氟化铝，氟化物催化剂...     

Bioavailability of fluoride administered as sodium fluoride or monofluorophosphate to humans

A double-bind cross-over study was conducted on four healthy subjects, aged 19-29 years, in order to determine the relative bioavailability and other pharmacokinetics features of fluoride (F) after single oral administration in fasting conditions of 2 mg F as sodium F (NaF) or sodium monofluorophosphate (MFP). The bioavailability was evaluated on the basis of the plasma levels and of the urinary excretion of F. Blood was sampled before and during the 8 h after the administration of the test solutions. For F excretion urine was sampled 12 h before the study and over the 8 h after the administration. Data were tested for statistically significant differences by ANOVA and Tukey's post hoc tests, and also by Student's t-test (p < 0.05). For the two formulations, the pharmacokinetics of F in plasma was characterized by a rapid absorption and by a peak (C_max = 0.1 μg/mL) which was reached 20 min after administration, followed by a biphasic elimination. In the 8 h following the administration the urinary excretion of F accounted for 35-41% of the administered dose, without significant differences between the two formulations. The AUCs (±S.D.) for NaF and MFP were 21.15 (±0.58) and 19.04 (±1.75) min μg mL⁻¹, respectively, and were not significantly different (p = 0.079). Based on the AUC and C_max of F in plasma and on the urinary excretion of F during the 8 h following administration, the relative bioavailabilities of the two F formulations were equivalent.     

Indirect determination of fluoride in aqueous samples by inductively coupled plasma atomic emission spectrometry following precipitation of CeF3

An indirect fluoride determination method has been developed based on the ICP-AES determination of excess cerium(III) ion after precipitation. From four cations—Y(III), Sr(II), Ce(III), La(III)-cerium(III) proved to be the best precipitate forming cation in the 0-20 mg L⁻¹ fluoride concentration range with the limit of detection of 1.4 mg L⁻¹. The precision (RSD) of the proposed method is 0.71% at 8 mg L⁻¹ fluoride. The role of sulphate ions in the formation of the fluoride precipitate was studied as well. The applicability of the technique for the study of solid hazardous wastes as well as for groundwater monitoring of a fluoride contaminated area is demonstrated.     

氟作业工人骨骼X线改变的分析

对９６６名氟作业工人选定的骨骼常规摄Ｘ光片,按其不同日摄氟量分组观片、记录。结果显示：①骨骼Ｘ线改变阳性率与日摄氟量呈正相关（ｒ＝０．８７９,Ｐ〈０．０１）;②不同部位的骨骼Ｘ线改变阳性率有差异;③骨骼Ｘ线改变的主要表现是骨密度增高、骨间膜增宽或钙化、关节、骨周、髓腔有改变、骨质增生、闭孔膜及韧带钙化等。     

Zwei Galliumfluorid-Ammoniakate: Ga(NH3)F3 und Ga(NH3)2F3

Two Gallium Fluoride Ammine Complexes: Ga(NH₃)F₃ and Ga(NH₃)₂F₃ Two gallium trifluoride ammines, Ga(NH₃)F₃ and Ga(NH₃)₂F₃, are obtained as single crystals through oxidation of gallium metal with NH₄HF₂ (Ga : NH₄HF₂ = 1 : 1.5) and NH₄F (Ga : NH₄F = 1 : 3.5), respectively, at 450 °C and 400 °C. Ga(NH₃)F₃ crystallizes with the non-centrosymmetric space group Abm2 (a = b = 544.6(2) pm, c = 986.6(4) pm) forming two-dimensional layers of [Ga(NH₃)F₅] octahedra. The addition of another NH₃ molecule in Ga(NH₃)₂F₃ (orthorhombic, Immm, a = 700.0(3) pm, b = 724.7(2) pm, c = 393.1(1) pm) leads to one-dimensional rods of [Ga(NH₃)₂F₄] octahedra running parallel [001] which are stacked in the [010] direction. Infrared spectra suggest hydrogen bonding (N–H…F) in Ga(NH₃)F₃, for Ga(NH₃)₂F₃ an unequivocal statement is not possible.     

Hydrogen fluoride analyzer for gases and aerosols

Many fire suppression agents are currently used, and the replacement candidates for these agents contain fluorine atoms. When these agents are used to extinguish a fire, large quantities of hydrogen fluoride gas can be produced from the thermal degradation of fluorinated organic compounds. A real-time analyzer has been developed to measure exposure levels of hydrogen fluoride gas and aerosols during fire suppression tests. A vacuum pump pulls air through a continuous denuder, where the toxic gas and aerosols are extracted from the air into an aqueous trapping solution. The trapping solution then passes through a flow cell, where a fluoride ion-selective electrode measures the fluoride ion concentration. A solenoid pump moves the trapping solution and calibration standards through the analyzer. Once calibrated, the analyzer can generate a concentration profile of hydrogen fluoride versus time. This hydrogen fluoride analyzer is portable and can be calibrated in about 5 min. It provides rapid response to hydrogen fluoride gas and aerosols, over a detection range from 1 to 5000 mg/m³.     

KZnF3中Ce3+→Eu2+的能量传递

研究了KZnF3中Ce3+和Eu2+的光谱特性,在共掺Ce3+和Eu2+的体系中,观察到了Ce3+对Eu2+的能量传递过程.计算了能量传递的量子效率,探讨了能量传递机理.研究发现,Ce3+的存在有利于Eu2+的f-f跃迁线状发射.