易解石族矿物的化学特征

易解石族矿物具有十分复杂的化学组成,根据现代矿物学分类的原则,可将其分为8个矿物种:易解石、钇易解石、钕易解石、钍易解石、铌易解石、钕铌易解石、维易解石及瑞易解石。易解石族矿物成分的变化与地质产状有密切联系。在某些易解石中富含的镧、铈、钕、铕、镝、钇、铌及钽等元素,可将其综合利用。     

褐钇铌矿族矿物的可见光光致发光谱和吸收谱研究

测定并讨论了白云鄂博变生态和退火晶态褐钇铌矿族矿物在 4 88 0和 51 4 5nm激光激发下的光致发光谱。分析表明 ,该族矿物的发光中心是Er3 和Eu3 ,其中褐钇铌矿的发光主要由Er3 产生 ,而Eu3 和Er3 的共同发光构成褐铈铌矿的发光谱。可见光吸收谱显示 ,Nd3 可能是该族矿物光致发光的重要敏化剂。     

中国稀土科技文献索引

地质与选矿001002003004005006007008009010011012 富礼镐易解石的发现,蔡根庆,矿物学报,1987,7(1),“. 稀土磷酸盐矿物合成的一些试验,黄舜华等,矿物学报,1987,7(2),173. 黄忆钮矿形成条件的实验研究,黄舜华等,矿物学报,1987,7(3),274. 新矿物—白云鄂博矿,傅平秋等,矿物学报,1987,7(4),287. 白云鄂博矿的晶体结构,傅平秋等,矿物学报,1987,7(4),298. 白云鄂博矿的电子衍射和结构象研究,刘维等,矿物学报,1987,7(4),305. 江西龙南花岗岩稀土风化壳中粘土矿物的研究,杨主明,地质科学,1987,(1),70. 冀北早太岩石Sm一Nd同位素年龄测定,乔广生等…     

白云鄂博矿床萤石型铁矿石中稀土分布规律研究

采用多元素分析、场发射扫描电镜、X射线能谱仪及AMICS自动矿物分析系统对白云鄂博矿床主、东矿内萤石型铁矿石中的稀土元素分布规律进行了系统地分析,发现稀土含量与稀土配分均存在一定的差异,并提出了精细化生产建议,指出La,Ce,Pr,Nd,Sm,Eu的最佳矿物原料分别为东矿氟碳铈矿、主(东)矿氟碳铈矿、主矿氟碳铈矿(独居石)、主矿独居石、东矿独居石、主(东)矿独居石。该研究对进一步认识白云鄂博矿床稀土资源和综合高效利用这一资源具有一定的指导意义。     

常见稀土氟碳酸盐氧同位素分馏研究

氟碳酸盐是重要的稀土矿物，本研究利用增量模式讨论其氧同位素分馏性质，计算的氧同位素富集顺序为：氟碳铈矿＞Ｃａ０．５ＢａＣｅ２（ＣＯ３）４Ｆ＞白云鄂博矿＞黄河矿＞氟碳铈钡矿。结合白云鄂博矿床氟碳酸盐矿物氧同位素分析数据，可看出理论预测的分馏顺序与实际相一致，计算的成矿温度与矿区地质相吻合。由于钡系列氟碳酸盐矿物可看成是ＣｅＣＯ３Ｆ与ＢａＣＯ３层状堆垛衍生的结果，故对矿物体衍生过程中氧同位素分馏的变化进行了讨论，并由此预测了中华铈矿和氟碳钡铈矿的氧同位素分馏曲线。     

成形滤纸片薄样X射线荧光光谱法测定铝合金中镧铈镨钕钐

研究了用成形滤纸片薄样X射线荧光光谱法测定铝合金中的镧、铈、镨、钕、钐。方法具有准确、快速、简便、经济等优点。各元素的测定灵敏度为La 48054,Ce 65923,Pr 93953,Nd 62622,Sm107630 cps/(mg/cm~2)。定量分析下限约为0.xμg/cm~2。     

我国稀土资源与生产以及稀土永磁材料的发展概况

我国稀土资源丰富,品种齐全,铈族稀土工业储量为世界稀土工业储量的五倍多,钇的储量相当于中国以外的世界钇资源储量。 我国内蒙白云鄂博铁矿是铁、稀土、铌、磷、锰和氟等多种元素的共生矿,是我国的主要稀土资源。包头稀土矿以铈族稀上为主,成分复杂,提取稀土的工艺技术难度较     

铈中微量镧、镨、钕与钇的光谱测定

本工作报告铈中杂质镧、镨,钕及钇的两种光谱测定方法。(1)将试样的氯化物溶液滴于经液体石腊处理过的碳电极上,干燥后以交流电弧激发进行摄谱。采用线对 La 4333.74/Ce 43330.90,Pr 4225.33/Ce4229.63,Nd 4061.09/Ce 4057.30及Y 4374.94/Ce 4376.88时测定灵敏度分别可达0.055％,0.089％,0.052％,0.025％。单次摄谱的均方误差分别为±4.7％,±10.8％,±7.0％及±7.0％。 (2)对于较纯的铈,则采用乙醚萃取先行分离,以浓缩其中所含的杂质,并采用谱线较少的元素钇作内标及载体,以补偿分离过程中损失。浓缩物仍以氯化物溶液状态用上述的激发方法进行摄谱。采用下列线对: La 4238.38/Y 4235.73,La 3988.52/Y 3951.60,Pr 4222.98/Y 4235.73,Nd 4232.38/Y 4235.73取样100毫克时,镧、镨及钕的测定灵敏度分别可达0,01％;0.025％及0.028％。一般误差约在±10％左右。     

Na—Ca—Ba—Re氟碳酸盐系列矿物的两个新变种

Ｃａ氟碳钡铈矿富Ｓｒ变种和白去鄂博矿富Ｃａ变种分别产于俄罗斯科半岛希宾碱性岩体的碳酸盐和内蒙古白云鄂博铌铁稀土矿床碳酸盐脉石中，据电子探针分析得到的晶体化学分别为：（Ｃａ０．４６，Ｎａ０．２８，□０．１６）０．９０Ｂａ１．０３（Ｃｅ０．８２，Ｓｒ０．３８，Ｌａ０．３５，Ｎｄ０．３２，Ｐｒ０．０９，Ｓｍ０．０１）１．９７（ＣＯ３）４Ｆ和（Ｎａ０．４４，Ｃａ０．３２，□０．２４）１．００Ｂａ１．０７（     

偶氮氯膦Ⅲ-溴化十六烷基三甲基铵分光光度法测定稀土总量

本文研究了用偶氮氯膦Ⅲ(CPAⅢ)-溴化十六烷基三甲基铵(CTAB)光度法测定稀土总量(RE),可以不经预分离直接测定合金钢、铝和镁合金中微量RE。方法简便快速,准确度良好。试验部分 (一)试剂与仪器 RE标准溶液:由铈、镨、钕的氧化物分别制成5微克/毫升铈、镨、钕的溶液。混合RE溶液按Ce∶Pr∶Nd=5∶2∶3混合。     

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%.     

Synthesis of 1-benzyloxypyrazin-2(1H)-one derivatives

Different approaches for the synthesis of 1-benzyloxypyrazin-2(1H)-one derivatives from simple amino acids have been investigated. A library of 33 precursors for the preparation of N-hydroxy pyrazinones was obtained in moderate to good yields.     

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.     

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.     

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.     

A general and convenient synthesis of 4-(tosylmethyl)semicarbazones and their use in amidoalkylation of hydrogen,heteroatom, and carbon nucleophiles

A general synthesis of previously unknown semicarbazone-based α-amidoalkylating reagents, 4-(tosylmethyl)semicarbazones, has been developed. The synthesis involved three-component condensation of semicarbazones of aliphatic or aromatic aldehydes with the same or other aldehydes and p-toluenesulfinic acid. The scope and limitations of this reaction were investigated. The compounds obtained were demonstrated to be an efficient α-(4-semicarbazono)alkylating agents. They were reacted with H- (sodium borohydride), O- (sodium methylate), S- (sodium phenylthiolate), N- (pyrrolidine, sodium succinimide), P- (trialkyl phosphites), and C-nucleophiles (sodium diethyl malonate) to give the corresponding products of the tosyl group substitution, 4-substituted semicarbazones, including analogues of nitrofurazone. Among the prepared compounds tested in vitro for antibacterial and antifungal activity, three nitrofuryl-containing semicarbazones exhibited high biological activities with minimum inhibitory concentration (MIC) values of 8–32 μg/mL.     

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.     

Synthesis of novel chiral bidentate hydroxyalkyl-N-heterocyclic carbene ligands and their application in palladium-catalyzed Mizoroki–Heck couplings and asymmetric addition of diethylzinc to benzaldehyde

A small library of new chiral bidentate hydroxyalkyl-imidazolium salts 1 is conveniently synthesized on multi-gram scale from inexpensive and commercially available chiral pool amino acids. The corresponding carbenes, generated by deprotonation of imidazolium salts 1, in combination with palladium(II) chloride were tested in the Mizoroki–Heck coupling reaction. The most significant results in terms of yields and reactivities were achieved with low catalyst loading. The catalytic activities of these imidazolium salts were also investigated in the asymmetric addition of diethylzinc to benzaldehyde. The use of MgO nanoparticles as an additive in conjunction with these ligands played a crucial role in increasing the efficiency of these reactions.