碘元素概念发展史及其教育价值

通过对碘元素概念发展历程的考证可知,1813年,盖·吕萨克首次提出碘元素概念,但当时碘元素和碘单质概念界定不清。至道尔顿提出原子论,赋予碘元素新的含义,首次将碘原子和碘元素结合在一起。20世纪40年代,碘同位素的发现完善了碘元素概念,形成现代碘元素观念。在化学教育中,须让学生认识到碘元素概念的发展史不仅是元素概念的发展史,也是科学思想的演进史和科学方法的发展史。     

培养高阶思维和核心素养的高考有效复习——以“从海洋到餐桌上的碘”为例

选择学生比较熟悉的碘元素,结合海带提碘和精碘制碘酸钾工业生产情境展开复习教学,综合利用元素性质、反应原理探索含碘物质之间相互转化的最优路径,并对转化过程中的某些现象进行实验探究。通过设置有梯度的问题串引导学生在思考、分析、探究、归纳中完成综合型学习任务,实现知识规律化和体系化整合以及高阶思维培养。     

碘系列实验的设计与思考

碘系列实验以生活中常见的含碘物质为实验素材,把碘元素的检测、碘元素的存在形态及其典型性质等化学学科知识与实验方法、学生的生活经验融为一体。阐述了碘系列实验的内容和设计原则,对碘系列实验内容的设计思路、教学价值和开发系列化实验的意义进行了分析,并提出了开发系列化贴近生活的实验应借鉴和注意的问题。     

甲状腺肿机制在合成蛋白质对Zn／Ca失调抑制I^—向I^0转化的研究

虽然碘缺乏假说一直被认为是导致甲状腺肿的病因，但实质并不清楚。本文根据中外文献资料、多学科交叉理论，结合江苏省苏南西部地区地甲病与环境地质条件关系综合研究，论述了碘元素在自然环境中分布差异取决于是否有适宜微生物生长繁殖的环境，碘元素靠生物吸收聚积，碘流失理论无法解释。人体甲状腺缺碘，并非环境缺碘，甲状腺肿机制在合成蛋白质时Ｚｎ／Ｃａ失调，摄入体内Ｃａ含量高，合成Ｃａ蛋白质高，阻碍Ｚｎ元素合成Ｚｎ蛋     

甲状腺肿机制在会成蛋白质时Zn/Ca失调抑制I~-向I~0转化的研究

虽然碘缺乏假说一直被认为是导致甲状腺肿的病因,但实质并不清楚。本文根据中外文献资料、多学科交叉理论,结合江苏省苏南西部地区地甲病与环境地质条件关系综合研究,论述了碘元素在自然环境中分布差异取决于是否有适宜微生物生长繁殖的环境,碘元素靠生物吸收聚积,碘流失理论无法解释。人体甲状腺缺碘,并非环境缺碘,甲状腺肿机制在合成蛋白质时Zn／Ca失调．摄入体内Ca含量高,合成Ca蛋白质高,阻碍Zn元素合成Zn蛋白质,Zn蛋白质合成的醉不足,摄入的无机碘（I-）不能被酶活化为分子砍（Io）合成甲状腺素,而经细胞外──肾系统排出体外,导致恩者尿中高I-、Ca2+,而甲状腺内缺碘的反常病理生化特征。     

四甲基氢氧化铵提取-电感耦合等离子体质谱法测定多种食品中的碘

建立了四甲基氢氧化铵(TMAH)提取-电感耦合等离子体质谱法(ICP-MS)测定多种食品中的碘.试样经5％的TMAH溶液于85℃恒温提取3h,离心过滤后的试液采用ICP-MS法测定,以碘元素特定质量数127(质荷比m/z)定性,以碘元素和185铼内标元素质谱信号的强度比值与碘元素的浓度成正比进行定量.结果 表明,碘在0...     

碘小姐的旅行

将碘元素拟人化,让其以卤素家族"四小姐"的身份,在这美丽的世界上走一走,并拟人化讨论了碘小姐的元素分布、物理性质以及生理活性,让读者在获得知识之余还能有美的享受。     

以文献阅读与分析发展学生的核心素养——以“海带中碘元素的分离及检验”为例

以高中“实验化学”模块的“海带中碘元素的分离及检验”为例,依据权威性、针对性与可读性的原则,选取符合要求的文献,创设情境组织教学。学生们在文献阅读与分析的过程中,多角度认知海带处理、氧化剂选择、碘单质提纯与检验等,体会使用文献的价值。实践证明在教学中引入文献,有利于开拓学生视野,提升学习兴趣。     

元素的生物效应在元素化学教学中的渗透与融合

基于大量素材探讨如何将元素的宏观生理效应、药用价值及其配合物生物效应的构-效关系等基础知识和前沿研究动态渗透到相关的元素化学的教学中,以使学生提高对元素化学学习的兴趣,加深对元素结构和性质的认识,激发学生对科学研究的热情。     

集体儿童膳食供给及头发中锌,铁,钙,碘元素含量调查

以华清村幼儿园２２５名儿童为对象进行了膳食供给情况调查和头发中锌、铁、钙、碘元素含量的测定。结果显示,膳食中钙元素的供给不足ＲＤＡ的５０％,头发检测钙、锌、碘、铁四元素分别为７６％、６０％、３７．８％、３４．７％的儿童达不到正常参考值标准,故除应加强膳食管理,为儿童提供科学、合理的平衡膳食外,还必须补充适量吸收好、利用率高的钙制剂,同时在监测下有针对性地补充铁、锌、碘元素。     

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%.     

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.     

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.     

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.     

Facile synthesis of bicyclic 1-arylpyrazol-5-ones

In this Letter, we described a facile method for constructing fused bicyclic 1-arylpyrazol-5-one ring system. We employed various methylene-containing carboxylic acids as the substrates and proved that the pyrazolone ring closure requires activated methylene group in intermediate II. Accordingly, a series of structurally diversified, fused bicyclic 1-arylpyrazol-5-ones was prepared in moderate to high yields using the requisite substrates.     

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.