电感耦合等离子体原子发射光谱法测定铝合金中镧、铈、钪的含量

当样品中硅的质量分数不大于2%时,采用盐酸(1+1)溶液10mL和数滴过氧化氢溶解0.100 0g样品;当样品中硅的质量分数大于2%时,先用200g·L~(-1)氢氧化钠溶液10mL溶解0.100 0g样品,加入盐酸(1+1)溶液15 mL酸化。以La 408.671nm,Ce 413.765nm,Sc 361.384nm作为分析线,采用基体匹配法来消除铝基体干扰。镧、铈、钪的线性范围为1.0~10.0mg·L~(-1),检出限(3s)分别为3.5,6.1,3.1μg·L~(-1)。应用该方法分析了镧、铈、钪质量分数在0.005 0%~0.500%内的铝合金样品,镧、铈、钪测定值之和与三溴偶氮胂分光光度法测得稀土元素总量相符。测定值的相对标准偏差(n=11)均小于6.0%。     

氧化钪分离富集方法的研究

1引言钪是化学元素周期表ⅢB族元素，它与镧系元素的外层结构和化学性质相似。钪的独立矿床极为稀少，工业上主要通过回收有色金属和稀有金属矿石中伴生的钪来制备钪。近年来，钪的提取技术不断改进，开拓出许多新颖的分离方法和技术，本文就是在此基础上采用萃取法和离子交换法对氧化钪的分离提纯进行研究，并应用于工业废料中回收钪，取得满意的结果。2实验部分2．1仪器与试剂东德PGS-2型电感耦合等离子体发射光谱仪；二（2-乙基已基）磷酸（上海有机试剂厂），TBP（天津化学试剂二厂），007阳离子树脂，201×7型阴离子树脂（南开大学…     

阴离子树脂苯取富集-分光光度法测定煤矸石中痕量钪

研究了对乙酰基偶氮氯膦(CPApA)与钪(Ⅲ)的显色反应,在HNO3介质中,在Triton X-100存在下,CPApA与钪(Ⅲ)反应生成摩尔比为1:1的稳定配合物,该配合物可用717型阴离子树脂交换柱萃取富集,再通过树脂相光度法测定钪,由此建立了测定钪的新方法.吸附配合物树脂相的最大吸收波长为690 nm,表观摩尔吸光系数为9.56×105 L·mol-1·cm-1.钪的质量浓度在0～480μg/L范围内符合比耳定律.经阴离子树脂交换柱萃取富集后,钪的测定灵敏度可提高数倍,大多数常见离子不干扰测定.方法应用于煤矸石痕量钪的测定,结果满意.样品分析结果的相对标准偏差小于5%,加标回收率为96.0%～102.5%.     

离子交换-溶剂萃取ICP-AES法测定红泥中的钪

采用偏硼酸锂熔样,试液通过离子交换树脂（Ｄｏｗｅｘ５０Ｗ－ｘ８）,用浓度为２ｍｏｌ／Ｌ的盐酸可将主量元素（铁、铝、钙、硅、钛、钠）和微量元素（镍、锰、铬、钒）洗脱,用浓度为６ｍｏｌ／Ｌ的盐酸定量洗脱钪、钇和镧系元素。用萃取剂：磷酸二（２－乙基己基）酯溶液能将钪选择定量地萃取到有机相中,钇和镧系元素仍留在水相中,用ＩＣＰ－ＡＥＳ法测定钪,光谱干扰都可排除,检出限１０ｎｇ／ｇ,回收率９８％。     

固-液萃取法研究1-苯基-3-甲基-4-苯甲酰基吡唑酮-[5]对钍、钪的萃取及钪的分析应用

本文以固体石蜡为溶剂,1-苯基-3-甲基-4-苯甲酰基吡唑酮-[5](HPMBP)为萃取剂,研究了钍、钪的萃取及反萃取条件。斜率比法示明石蜡中配合物组成分别为Th(PMBP)_4,Sc(PMBP)_3,人工合成钢铁样品的分析结果Sc~(3+)的回收率分别为99.6％和100％。     

双波长法测定混合稀土氧化物中钪

研究了镧，钐，钕，镱，铒分别对钪的增感作用。用大量的镧作为增感试剂和化学干扰抑制剂，并引入了双波长（６０７．９ｎｍ和６０７．６ｎｍ）差示法克服光谱干扰，对钪单氧化物蒸气发射光谱法测定了研究。测定了人工合成混合稀土氧化物样品中的钪，获得满意结果。     

钪—铋—三溴偶氮胂混合多核络合物显色反应及其在钪光度分析中应用研究

本文研究了钪-铋-三溴偶氮胂络合物的共显色反应。实验表明,共显色反应是由于形成混合多核络合物所致。钪络合物最大吸收峰在635nm,表观摩尔吸光系数为7.1×10~4L·mol~(-1)·cm~(-1)。钪在0～5μg/25ml遵守比尔定律。     

不对称变色酸双偶氮胂类试剂与铋—钪的共显色反应及分光光度测定铋的研究

本文研究了十种变色酸双偶氮胂类试剂与铋—钪的共显色反应,发现其中三溴偶氮胂等五种试剂与铋—钪有共显色反应。铋、钪与试剂生成的配合物的表现摩尔吸光系数为9.4×10~4L·mol~(-1)·cm~(-1)。大量的常见离子不干扰铋的测定,可不经分离直接测定合金中的微量铋。     

四酸密闭消解-电感耦合等离子体质谱(ICP-MS)法测定铀矿中的铼和钪

建立一种准确测定铀矿中铼和钪含量的方法,为铀矿中伴生元素的分析与研究提供数据支持、对探勘铼钪矿实现战略资源合理利用化有着重大意义。采用氢氟酸-硝酸-盐酸-高氯酸四酸溶解样品,利用密闭聚四氟乙烯坩埚-电热板加热方式来测定铼钪,建立了电感耦合等离子体质谱(ICP-MS)法测定铀矿中铼和钪的方法,探讨了分解方法、称样量、酸用量、溶样温度及时间、基体干扰、内标选择的影响。实验结果表明：酸溶分解结果准确性高于碱溶分解,3 mL HF、4 mL HNO3、2 mL HCl和1 mL HClO4为最佳消解体系,0.05 g~0.10 g、10 mL~12 mL为最佳称样量和酸用量,闭盖160 ℃、开盖190 ℃ 18 h为最佳溶样条件,选择碰撞气流速为3.0 mL/min,稀释气流速为0.8 L/min降低基体干扰,In作为内标能够达到测试要求。该方法操作简单同时将铼钪测试,其中铼和钪的检出限分别为0.006 mg/kg和0.366 mg/kg;铼准确度在92.9%~98.4%,相对标准偏差在2.4%~5.7%,钪准确度在93.5%~98.2%,相对标准偏差在1.6%~6.2%;铼加标回收率为87.2%~93.8%,钪加标回收率为90.7%~92.3%,检出限低,精密度良好,灵敏度低满足铀矿中铼和钪的分析要求。     

聚乙烯醇存在下钼酸盐和罗丹明B光度法测定钪

在聚乙烯醇存在下，钪相杂多酸和罗丹明Ｂ（ＲＢ）形成离子缔合物，其最大吸收位于５７０ｎｍ，表观摩尔吸光系数ε值为５．６２×１０＾５Ｌ．ｍｏｌ＾－１．ｃｍ＾－１，服从比耳定律范围０－１．０μｇＳｃ／２５ｍＬ，检出限１．１ｎｇ／ｍＬ（ｎ＝９），考察了５０多种外来离子影响，缔合物的摩尔组成为Ｓｃ：Ｍｏ：ＲＢ＝１：１２：６，方法用于地质样品中钪的分析，结果满意。     

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.