沉积碳氟磷灰石中痕量碘的SIMS定量分析

采用合成的标样对微细碳氟磷灰石中痕量碘进行了离子探针（ＳＩＭＳ）定量分析，给出了碘浓度与其二次离子相对强度的线性方程，对不同组构类型的沉积磷灰石进行的ＳＩＭＳ微区显微分析表明：针柱状结晶良好的微细磷灰石含碘很低，碘主要富集于生物成因的超微莓球磷灰石中。碘在磷块岩中分布不均匀性是受其超微组构制约的，ＳＩＭＳ微区分析深入地揭示了富碘磷块岩中碘的赋存特征。该法也可应用于生物骨骼、化石等磷酸盐样品中卤素的     

利用海藻中的碘培育富碘蔬菜防治IDD病的初步研究

以培育“绿色”富碘蔬菜，提高碘的土壤背景值，防治IDD病为目标，利用海带中的碘作为碘肥原料，进行了4种蔬菜的施碘实验。结果表明，通过施加硅藻土海藻碘肥，可培育出含碘量4～120mg/kg的叶菜类蔬菜(菠菜和白菜)和2～30mg/kg的果实类蔬菜(西红柿和萝卜)。不同作物对碘的富集能力不同，其由大到小顺序为：白菜，菠菜，西红柿和萝卜；不同部位对碘的吸收能力也不相同：叶子大于果实和根部。作物通过叶面从空气中吸收碘的能力和通过根部从土壤中吸收碘的能力相当。土壤对碘的保持能力有限，从低施肥量到高施肥量，碘在土壤中的残留率从50％下降到13％。就培育日常食用性蔬菜而言，适宜的施碘量为5～10mg/kg。     

微分伏安法测定微量碘

采用过量联合氧化剂高锰酸钾-次氯酸钠氧化试液中碘至IO3-,剩余的高锰酸钾和次氯酸钠用过量的亚硫酸钠反应除去,利用IO3-的电活性,建立了在四硼酸钠-吐温-80底液中的线性扫描伏安法测定微量碘的方法.优化了试验条件,研究了伏安特性.在最佳试验条件下,一阶导数峰电流与碘质量浓度在0～16 μg·L-1叫范围内呈线性关系(r=0.996 4),检出限为0.6 μg·L-1.对共存离子作了干扰试验,表明方法的抗干扰能力较强,用于食品中微量碘的测定结果的相对标准偏差(n=6)值均小于0.9%,加标回收率在97.8%至99.2%之间.     

电感耦合等离子体质谱法同时测定矿泉水中痕量溴和碘

建立了电感耦合等离子体质谱法(ICP-MS)同时测定矿泉水中痕量溴、碘,比较了不同酸碱度对溴、碘测定的影响。测量过程中对溴、碘的记忆效应进行消除,选择了最佳的工作条件,溴、碘的方法检出限分别为0.63,0.112μg/L,相对标准偏差分别为3.1%和1.8%,加标回收率为96%～107%。对国家标准水样进行了测定,测定结果与推荐值一致性较好。     

食品中碘的光谱电化学法测定

本文研究了用光谱电化学法测定食品中的碘，探讨了最佳的测定条件，用于海带，海带表层盐及模拟碘盐中碘的测定，结果满意，回收率高，抗干扰力强，操作快捷，方法简单易行。     

一种合成N-苯基苯并咪唑的新方法

成功开发出一种直接合成N-苯基苯并咪唑的新方法.在不使用金属催化剂与强碱的条件下,通过苯并咪唑与二苯基碘三氟甲磺酸盐的反应合成了目标化合物,采用1H NMR与13C NMR技术对目标化合物进行了表征,并确定了最佳反应条件.在苯并咪唑与二苯基碘三氟甲磺酸盐的物质的量比为1∶1.2、溶剂乙醇/二甲苯的体积比为1∶4、反应温度为120℃、反应时间为24h的最佳反应条件下,使目标化合物的产率达到了52.0％,并回收了等量的碘苯.此外,通过高效液相色谱技术进行跟踪监测,对该反应的机理进行了探讨.     

甲醛次硫酸氢钠二水合物促进的醌芳基化反应

以甲醛次硫酸氢钠二水合物（rongalite）为电子供体,碘代芳烃为芳基化试剂,在温和条件下实现了醌的芳基化反应。以苯醌和对硝基碘苯的反应为模板反应,考察了碱、溶剂、温度和物料比等对反应的影响。结果表明,最佳合成条件为：对硝基碘苯（0.2 mmol）,苯醌（1 mmol）,甲醛次硫酸氢钠二水合物（0.4 mmol）,氢氧化钾（0.6 mmol）,DMSO(1 mL),氮气氛围,80℃,反应24 h。在该条件下,目标产物收率可达82%。该反应体系对不同的碘代芳烃和醌均表现出了良好的适用性,收率在62%～84%之间。     

碘量滴定法测定过氧化氢溶液浓度的改进

研究了用碘量滴定法测定过氧化氢浓度时，试剂的加入顺序和放置时间对测定结果的影响。结果表明，在用碘量滴定法测定过氧化氢浓度的过程中，酸化条件下，I^-与H2O2反应的最佳时间为5～10min。与高锰酸钾氧化法相比，碘量法测定效果较好一些。     

碘-淀粉体系褪色光度法检测美白霜中对苯二酚

建立了基于碘-淀粉体系的褪色分光光度法,用于检测美白霜中对苯二酚的含量。碘能被捕获到直链淀粉螺旋状结构中,形成碘-淀粉蓝色复合物,在波长578 nm有最大吸收峰。当存在对苯二酚时,碘和对苯二酚发生氧化还原反应,碘被还原为碘离子,碘-淀粉体系蓝色变浅。建立波长578 nm的吸光度降低值与浓度的线性关系,确定对苯二酚的含量和检出限。对反应条件进行了优化,结果表明,在最佳实验条件(反应介质pH为2,氧化还原反应时间为30 min, 1×10^-3 mol·L^-1碘标准溶液用量为0.8 mL,0.5%淀粉溶液用量为1.0 mL)下,所建立的方法检测对苯二酚灵敏度良好：检测限为0.35 mg·L^-1,线性范围为0.5～4.5 mg·L^-1。该方法可用于美白霜中对苯二酚的快速测定,检测结果与文献报道的方法一致。     

表面活性剂存在下碘阴极溶出特性及其应用的研究

研究了十六烷基三甲基溴化铵对碘富集效果的影响。由于该表面活性剂的作用,大大提高了碘阴极溶出的灵敏度。线性范围为5×10~(-10)～10~(-7)g·ml~(-1)。用于自来水中痕量碘的测定,其平均回收率为96.6％。     

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.     

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.     

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.     

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.     

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.