三辛基氧化膦(TOPO)萃取铟的研究

本文研究了三辛基氧化膦(TOPO)自盐酸溶液中萃取铟的性能,其萃取率是随酸度的增加而增加。与P_(350)和TBP相比较,萃取能力大小顺序为:TOPO>P_(350)>TBP经斜率法和化学分析法研究确定,TOPO白盐酸溶液中萃取铟的反应为:In_((a))~(3+)+H_((a))~++4Cl_((a))~-+2TOPO_((o))F(?)HInCl_4·2TOPO_((o))IR和NMR研究证明:铟是以H[InCl_4]形式被萃入TOPO有机相中的。     

高强度丝蛋白/聚乙二醇冻凝胶的制备和表征

以聚乙二醇为交联剂,通过简单的冷冻融化过程制备了一种具有多孔结构的丝蛋白(SF)/聚乙二醇(PEG)高强度冻凝胶材料。利用红外光谱、扫描电镜和万能材料试验机等研究了该冻凝胶的构象转变、微观形貌、力学性能和溶胀行为。结果表明,PEG的加入可以促进SF分子链向更加稳定的结晶构象转变,并且冻凝胶的微观形貌和力学性能通过调节冷冻温度(T_(Freeze))、PEG用量(m_(PEG)/m_(SF))和SF质量分数等进行调节。在T_(Freeze)=-20℃、w_(SF)=0.16、m_(PEG)/m_(SF)=0.50的条件下,该冻凝胶可以压缩至90%以上,并能承受3.5 MPa应力而不发生永久性形变和破裂,其压缩模量可高达0.44 MPa。循环压缩实验表明该冻凝胶具有出色的回复能力,拉伸测试表明其杨氏模量和韧性可分别达到4.15 MPa和680.81 kJ/m~3。此外,该冻凝胶的孔状结构分布均匀、互相连通且溶胀性能优异。     

介孔碳-碳纳米管-硫化铜复合材料对电极的制备及其在量子点敏化太阳能电池中的应用

首先研究了介孔碳(MC)、碳纳米管(CNT)和不同MC/CNT质量比(m_(MC)/m_(CNT))制备的MC-CNT二元复合材料对电极的光电转换效率(PCE),进一步加入预先水热合成的CuS纳米材料,制备出MC-CNT-CuS三元复合材料对电极,同时探讨了CuS添加量和膜厚对对电极PCE的影响。实验结果表明,当m_(MC)/m_(CNT)=3/2时,2种碳材料能最大程度地发挥协同作用,使电池性能最好,PCE达12.69%。再加入0.4 g CuS时PCE可进一步提高,且对电极印刷5层时最优,此时所组装的电池获得的PCE最高(13.18%)。     

葡聚糖凝胶柱层析法测定黄芩苷脂质体载药性能的研究

采用逆相蒸发法制备黄芩苷脂质体,通过葡聚糖凝胶G-50柱层析分离游离黄芩苷和黄芩苷脂质体,比较不同流速和不同上样量条件下的分离效果,考察包封率测定方法的回收率,确定黄芩苷脂质体包封率的测定方法,并对黄芩苷脂质体的制备工艺进行优化。结果表明,以PBS为洗脱液(柱直径Φ为16mm,床层高度h为18cm),当采用流速0.5mL/min进行洗脱,进样量为3mL时,黄芩苷脂质体和游离黄芩苷的分离效果最好,且该方法测定包封率的回收率较高;据方差分析可知,大豆磷脂与胆固醇质量比(m_(大豆磷脂)/m_(胆固醇))、有机相与水相体积比(V_(有机相)/V_(水相))和黄芩苷浓度均对黄芩苷包封率有显著性影响,优化条件为:m_(大豆磷脂)/m_(胆固醇)为2:1、V_(有机相)/V_(水相)为3:1、黄芩苷浓度为1.6mg/mL。该条件下,黄芩苷脂质体包封率为(81.22±1.22)%,可采用葡聚糖凝胶G-50柱层析分离测定黄芩苷脂质体的包封率。     

一种金属钙化学分析用试样的制样方法

正公布号:CN105043829A公布日:2015.11.11申请人:马钢(集团)控股有限公司摘要:本发明公开了一种金属钙化学分析用试样的制样方法,取钙试样后,先用洗酸溶解表面氧化钙,剩余质量为m_1,再放入相同浓度稀酸中,反应后称量质量为m_2,将第二次溶液定容后,得到分析试液,分析试液中含试样质量m=m_1–m_2;选择化学分析方法对分析试液进行元素含量分析。与现有     

横向加热石墨炉的分析性能研究

研究了横向加热石墨炉的恒温性能和分析性能，并与Ｍａｓｓｍａｎｎ型炉进行了比较，结果表明，横向加热石墨炉具有较好的恒温性能，其原子化时间短，原子化温度低，原子吸收信号的占有时间短，特征质量ｍ０值低。     

微波等离子体原子吸收光谱法测定铜的研究

等离子体作为原子化器在原子光谱法中已经获得了广泛的应用.等离子体原子吸收光谱法目前多限于用ICP作为原子化器.1988年本室首次采用常压氩MIP作为原子化器,利用电热进样的方式引入样品,成功地测定了Cu、Ag和Pb.特征浓度分别为0.04(Ag)、0.04     

无火焰原子化-原子吸收光谱法测定不锈钢中砷量

在火焰原子吸收分光光度计火焰上方放置一只特制的不锈钢管作为原子化器,将不锈钢样品溶液定量滴加在不锈钢原子化管内,在乙炔-一氧化二氮高温火焰下对不锈钢样品中微量砷的含量进行无火焰原子化测定,以标准加入法进行定量分析.方法的特征质量为59 pg/1%,绝对检出限(3σ)为3.6 pg.     

电沉积分离富集钨丝电热原子吸收测定微量钯

本文介绍一种电热原子吸收光谱分析测定微量钯的新方法。将溶液中微量钯电还原沉积到钨丝表面,该钨丝再通以一定功率电流使其表面沉积的金属钯蒸发原子化并测量吸光度。确定了各实验参数最佳值,讨论了各种影响因素。电沉积时间(?)秒时,检出限为1.49ng/mL,相对标准偏差为5.18％,钯含量在0-30ng/mL范围内与吸光度呈线(?)关系。方法可用于若矿、催化剂及阳极泥等试样的发析,用管理样进行了分析结果对照,准确度和精密度均较好。     

N,N（二甲庚基）乙酰胺萃钯机理研究

本文研究了N,N二甲庚基乙酰胺(N_(s03))从氯化物体系中萃取钯的机理。应用等摩尔系列法和斜率法确定萃合物组成为:(CH_3CONR_2H)_2PdCl_4。通过紫外-可见光谱法研究,证实N_(503)萃取钯的机理属阴离子交换反应,其萃取方程式为: 2CH_3CONR_2HCl_((o)) PdCl_4~(2-)(a)?(CH_3CONR_2H)_2PdCl_4(o) 2Cl~-(a)     

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%.     

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.     

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.     

Selective syntheses of 2H-1,3-oxazines and 1H-pyrrol-3(2H)-ones via temperature-dependent Rh(II)-carbenoid-mediated 2H-azirine-ring expansion

The Rh(II)-catalyzed reaction of 2-carbonyl-substituted 2H-azirines with ethyl 2-cyano-2-diazoacetate or 2-diazo-3,3,3-trifluoropropionate provides an easy access to 2H-1,3-oxazines and 1H-pyrrol-3(2H)-ones. These compounds can be selectively prepared from the same starting material using temperature as the only varied parameter. The 2-azabuta-1,3-diene intermediate, a common precursor for both heterocyclic products, isomerizes into 2H-1,3-oxazine under kinetic control, while 1H-pyrrol-3(2H)-one is the sole product of the reaction at elevated temperatures. According to DFT-calculations a one-atom oxazine ring contraction involving ring-opening to a 2-azabuta-1,3-diene intermediate, followed by a 1,5- and 1,2-prototropic shift leads to the consecutive formation of imidoylketene and azomethine ylide, which then further undergo cyclization to the pyrrole derivative.     

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.