必需微量元素与儿童健康研究进展

就14种必需微量元素对儿童健康的利弊进行了综述，其中包括：铁、锌、锰、碘、铜和钼，铬、镍和钴，硒和锡，氟和钒，硅。必需微量元素与儿童生长发育息息相关，但过量则会对儿童产生不利影响。     

电感耦合等离子体原子发射光谱法测定煤和焦炭中硅、钙、镁和铝

煤和焦炭是炼钢、炼铁的重要原料。原料中硅、钙、镁和铝含量对于钢铁的冶炼具有重要影响。传统的测定方法是把样品灼烧后用硝酸、氢氟酸溶解,硅采用硅氟酸钾滴定法,钙、镁和铝采用EDTA滴定法,该方法不仅分析步骤繁琐,分析周期长,而且使用氢氟酸给人体和环境带来伤害和污染。本工作在文献[1-3]方法的基础上,用电感耦合等离子体原子发射光谱法(ICP AES)测定煤和焦炭中硅、钙、镁和铝的含量,此方法能代替原有的化学方法。     

人体内的氟

成年人体内氟约为２－９ｇ，比锌略多，仅次于硅和铁。人体内的氟含量由于受铝、钙、镁等元素的影响而有所波动。但是，从满足人体对氟的需要到由于过多而导致中毒的量之间相差不多。因此，氟对人体的安全范围比其他元素要窄得多。正因为这样，就更要注意自然界、饮水及食物中氟含量对人体健康的影响，尤其是工业排放的氟对环境的污染给人带来的危害。氟的生理需要量为０－５～１ｍｇ／ｄ。氟在人体中的分布主要集中在骨骼、牙齿、指甲和毛发中，尤以牙釉质中含量最多，骨骼中以长骨的含氟量最多。依次为股骨＞肱骨＞掌骨＞颅骨＞腰椎。男人…     

无机阴离子吸光光度法的新进展

本文综述了氟、氯、溴、碘、硫、氮、碳、硼、硅、磷、砷等无机阴离子的吸光光度测定法的进展,重点讨论了某些有机试剂和三元配合物体系在这一领域的应用前景。参考文献167条。     

核壳乳液聚合法制备含氟硅丙烯酸酯乳液

以氟醇RfCH2CH2OH和乙烯基硅氧烷VTES为原料合成的氟硅单体,与甲基丙烯酸甲酯、丙烯酸丁酯在复合乳化体系中通过核壳乳液聚合制备了稳定的氟硅共聚乳液。对氟硅单体和氟硅丙烯酸酯共聚物的结构用红外光谱进行了表征,结果表明,得到了目标单体和共聚物。共聚物的TEM形态观察发现,乳胶粒子具有明显的核壳结构,平均粒径在125 nm左右。与丙烯酸酯共聚物相比,氟硅丙烯酸酯共聚物乳胶膜的吸水率降低至8.32%,热分解温度提高了23℃,耐溶剂性与氟硅单体的含量关系不大。     

氟烷基化和氟烷氧基化的研究 钯(O)催化氟烷基碘对烯烃的加成反应

氟烷基碘通过光、热、自由基引发剂引发对烯烃加成。1984年Ojima等报道过渡金属羰基络合物也能催化氟烷基碘对重键的加成。我们前已报道铜在乙酐、二缩二乙二醇二甲醚(DG)或乙腈中通过单电子转移引发氟烷基碘与烯烃、炔烃反应,反应条件温和产率较高。但钯是否也能催化氟烷基碘与烯烃反应仍属未知。本文首次报道四(三苯基膦)合钯(O)催化氟烷基碘对烯烃的加成反应。     

人参、当归中微量氟的离子色谱分析

近年来,对中药研究的报道大多数侧重于有机成份的分析,而对其中无机成份研究较少。文献报道了126种中药中微量元素的系统分析,但未对人体必需的十四种微量元素之一——氟进行测定。氟是人体必需的微量元素,对牙齿及骨骼的形成和结构,以及钙和磷的代谢均有重要的作用。维持人体内部微量元素平衡的主要来源是食物和药物,为此本文选用人参和当归二种中药,用离子色谱法测定其煎剂中的微量氟,对探讨中药中微量成份的分布与疗效之问的关系有着一定的意义,人参和当归中微量氟的离子色谱分析尚未见文献报道,本文提出了一种简便、快速、准确地测定中药煎剂中微量元素氟的可靠的分析方法。     

氟烷基化和氟烷基化的研究 4.铜引发氟烷基碘对乙烯基三甲基硅烷的加长及其立体专一性合成相应的烯烃

在催化量的铜存在下,氟烷基碘R~FI(1)与乙烯基三甲基硅烷(2)在乙腈中反应生成高产率的氟烷基化产物3,二碘化物I(CF~2)~nI(4)也能与2反应生成单烷基化产物5和双烷基化产物6, 5和6量的相对比例取决于所用2的量,这类反应能被对苯二酚阻止;被对二硝基苯部分阻止,碘苯未能捕获到氟烷基铜中间体。表明反应可能是单电子转移引发的自由基链式机理.3与二乙胺反应得高产率的反式氟烷基三甲基硅乙烯7. 3与氢氧化钾在乙醇中反应得到的是7及其顺式异构体的混合物,将混合物用少量的溴处理可得纯的反式烯烃。     

烯烃类衍生物的碘三氟甲基化反应

在ZnI2为催化剂,Togni试剂为三氟甲基化试剂,CHCl3为溶剂的条件下,以中等收率(30%~65%)实现烯烃的碘三氟甲基化反应,合成了一系列既含碘又含三氟甲基的酯类、酮类、酰胺类、腈类等化合物,其结构经1H NMR,13C NMR,19F NMR,IR,MS和HR-MS表征。其中4,4,4-三氟-2-碘丁酰胺,4,4,4-三氟-2-碘-N,N-二甲基丁酰胺和6,6,6-三氟-4-碘-3-己酮为新化合物。     

可见光/路易斯碱协同催化的三氟甲基取代烯烃脱氟硅化反应研究

以三氟甲基取代烯烃为底物,使用硅硼烷为硅自由基供体,开发了一项可见光/路易斯碱协同催化的脱氟硅化反应新技术,实现了多样性偕二氟烯丙基硅砌块的绿色高效合成.新反应以奎宁环为路易斯碱催化剂,通过其对硅硼键的辅助活化促进硅自由基生成,表现出绿色温和、体系简单、易于放大、底物适用范围广和官能团兼容性强等优势.此外,本研究还初步展示了该类合成砌块在多类型含偕二氟甲基结构单元构建中的应用.     

5- and 7-substituted 2-methyl-8-quinolinols

The synthesis and characterization of the 5- and 7-monosubstituted 2-methyl-8-quinolinols where the substituents are fluorine, chlorine, bromine, iodine, nitro, amino, and sulfonic acid groups were carried out. The bischelates with copper(II) of those ligands containing hydrogen, fluorine, chlorine, bromine, iodine, and nitro are also reported.     

氟元素与人体健康

氟元素是人体必需微量元素，在人体内主要分布于骨骼和牙齿中。氟通过各种途径对人体发生作用。人体内少量的氟对于生长发育，骨骼代谢等有一定的影响，而含氟量过量或过少会引起某些疾病，并且氟的特性对于人体健康也有影响。     

土壤中化学元素与地氟病的生态学比较研究

为了解地氟病区土壤化学元素异常分布情况,给全面查找地氟病病因提供依据,采用生态学比较研究对各乡镇患病率与土壤化学元素水平做了相关分析.结果表明,巫山县土壤中铅、镍、氟、pH 与患病率有较弱的正相关关系;奉节县土壤中汞、镍与患病率有较弱的正相关关系.巫山县土壤氟和碘分别是其背景值的1.84、2.89倍,患病率高达65.3...     

Comparative study of activation analyses for the determination of trace halogens in geological and cosmochemical samples.

Halogens (fluorine, chlorine, bromine and iodine) were determined by activation analyses (neutron activation analysis (NAA), photon activation analysis (PAA) and prompt gamma-ray analysis (PGA)) for geological and cosmochemical solid samples. We studied how each analytical method was for the determination of trace amounts of halogens in rock samples. Radiochemical NAA (RNAA) showed the highest analytical reliability for three halogens (chlorine, bromine and iodine), whereas a set of four halogens (fluorine, chlorine, bromine and iodine) could be determined in principle by radiochemical PAA (RPAA) from a single specimen. Although it is a non-destructive method, PGA showed an analytical sensitivity for chlorine comparable to those of RNAA and RPAA.     

Quantum-chemical cluster modeling of the interaction of fluorine atoms with the (111) surface of silicon

The interaction of atomic fluorine with the Si(111) face was studied by the MNDO method. The energies of adsorption of the fluorine atoms on the surface as well as the values of the barriers to its incorporation and desorption from the subsurface layer of silicon were calculated taking into account the surface structure relaxation. It was found that a chemical bond is formed between the fluorine atom incorporated into the silicon and the adjoining surface silicon atom.Translated from Teoreticheskaya i Éksperimental'naya Khimiya, Vol. 28, No. 3, pp. 247–252, May–June, 1992.The authors wish to express their gratitude to P. A. Aleksandrova for fostering interest in the investigation and for her helpful suggestions.     

氟中毒及其治理

“氟魔”严重威胁着我国西南和西北等地人民的身体健康。氟本是人体必需的微量元素之一,但超量则会导致氟中毒:氟斑牙或氟骨症。本文概述了氟制取的悲壮历史和氟性质的特殊性,探讨了氟与人体健康的辩证关系和氟中毒的机理及表现,介绍了西南地区氟中毒的原因,提出了消除氟中毒的对策。     

Subphthalocyanine-fused dimers and trimers: synthetic, electrochemical, and theoretical studies

Subphthalocyanine (SubPc)-fused dimers and trimers bearing fluorine, iodine, and thioether peripheral substituents were synthesized and characterized. Absorption spectroscopy and electrochemical studies revealed (i) that the substituents have a strong effect on the electronic properties of the macrocycles and (ii) that there is good communication between the subphthalocyaninic moieties within the oligomeric structures. Theoretical calculations at DFT/6-31G(d,p) computational level and electron density studies support the experimental findings. The frontier orbitals in the dimers and trimers were also shown to be significantly altered with respect to those of SubPcs as a consequence of the extension of the conjugation associated with symmetry breaking. Time-dependent density functional theory calculations reproduced the differences observed in the UV-vis spectra of the fused dimers and the monomeric SubPcs.     

Lactonizations of carboxylic acid-substituted 3-fluorodihydropyridines with electrophiles: peculiar behaviour of F(+)

Whereas for 3-fluorodihydropyridine-substituted carboxylic acids electrophiles such as HCl, iodine, bromine and peracids discriminate the double bond lacking and that bearing fluorine, no such differentiation took place in the case of electrophilic fluorine since the formation of both mono and gem-difluorolactones took place.     

13C NMR of α-haloketones

The carbon chemical shifts of several series of α-haloketones have been measured. Whereas the carbon carrying the halogens shows a regular downfield shift with increasing electronegativity of the substituents, the adjacent carbonyl carbon is shifted upfield by chlorine, bromine and iodine, and is little affected by fluorine substitution. The conformational implications of these results are discussed.     

Ionization energy of core electrons in haloderivatives. Polarization effect in F-, Cl-, Br-, and I-centered radical cations

Ionization energies of core electrons of the fluorine, chlorine, bromine, and iodine atoms in 27 reaction series of haloderivatives depend on the inductive, the resonance, and the polarization effect; the latter has not been considered before. The contribution of the polarization effect varies in a broad range and in some cases exceeds 50%. Halocentered radical cations formed by the abstraction of the core or valence electron from the molecule slightly differ in the polarization effect value.