芦丁在离子液体双水相中分配性能

建立了室温离子液体四氟硼酸1-丁基-3-甲基咪唑([Bmim]BF4)和NaH2PO4组成的双水相萃取体系并用于对芦丁的萃取分离研究。考察了离子液体用量、芦丁的浓度、盐的加入量、溶液酸度和加入其它物质对芦丁在两相中分配的影响。结果表明,离子液在1.0~2.5 mL,磷酸二氢钠加入量在1.0~2.0 g,加入卢丁溶液0.5~2.5 mL,酸度在pH值为2~7范围,卢丁在离子液体双水相体系中有较高的萃取率(E%>90)。除阳离子表面活性剂外,其余大部分物质不影响相比和卢丁的测定。离子液相中卢丁的最大吸收波长为358 nm,与乙醇水溶液中比较,最大吸收波长发生紫移,表明离子液与卢丁发生了作用。利用离子液体双水相体系,测定了银杏叶中卢丁的含量。     

离子液体双水相体系萃取分离牛血清白蛋白

建立了由亲水性离子液体四氟硼酸1-甲基-3-丁基咪唑([Bmim]BF4)和KH2PO4形成的双水相体系萃取分离牛血清白蛋白(BSA)的新方法。研究了不同盐及盐的浓度、离子液体浓度以及蛋白质用量、溶液酸度、其它共存物质对双水相成相及BSA萃取率的影响,结果表明,磷酸二氢钾盐浓度为80g/L,离子液体浓度在160~240mL/L,BSA的浓度为30~50mg/L,溶液酸度在pH4~8范围,离子液体双水相体系对BSA有较高的萃取率。用加入不同类型表面活性剂探讨了离子液体与蛋白质之间的作用。     

[Bmim]BF4-NaH2PO4双水相萃取-高效液相色谱法测定水中痕量氯酚类内分泌干扰物

利用离子液体双水相萃取-高效液相色谱(HPLC)法测定了水中痕量氯酚类内分泌干扰物.以2,4-二氯酚(2,4-DCP)、2,6-二氯酚(2,6-DCP)和对氯苯酚(4-CP)为目标分析物,考察了影响离子液体双水相萃取率的主要因素,如分相盐的浓度、水相pH值、萃取时间及离子液体加人量.当NaH2PO4的浓度为0.5 g/...     

离子液体萃取-分光光度法测定水中结晶紫

合成了离子液体六氟磷酸1-丁基-3-甲基-咪唑[Bmim][PF_6],并以其为萃取剂,对结晶紫进行萃取。实验考察了溶液pH值、离子液体用量、盐的加入量、温度、共存离子等因素对结晶紫萃取率的影响。结果表明,溶液酸度在pH 3.2~6.0,在10.00 mL水中,离子液体加入量为0.40 mL时,离子液体对结晶紫的萃取率最大。结晶紫的质量浓度在0.1~2.0μg·mL~(-1)范围内与吸光度呈线性关系,相关系数R=0.9923。方法的检出限为0.02μg·mL~(-1),平均回收率在93.0%~96.6%之间。     

吡虫啉和啶虫脒的离子液体双水相萃取顺序注射光度分析研究

建立了由亲水性离子液体Cl与K2HPO4·3H2O形成的双水相体系萃取富集农药吡虫啉和啶虫脒的方法.考察了不同种类盐对成相的影响;系统实验了盐的加入量﹑农药溶液体积及离子液体加入量对相比的影响;研究了盐及pH变化对吡虫啉和啶虫脒萃取率的影响;并考察了萃取后农药最大紫外吸收光谱的变化.结果表明:当采用0.40 g离子液体,7.60 g K2HPO4·3H2O,6 mL农药水溶液在pH 9萃取农药,萃取率可达100%;少量的离子液体能达到较高的富集率.在最佳萃取条件下,将方法用于环境水样中吡虫啉和啶虫脒农药的萃取测定,加标回收率和相对误差分别在98.7%～102.0% 和2.2%～3.5%之间,结果满意.     

乙醇-正丙醇-磷酸二氢钠多元混合双水相体系萃取/检测湖水中的诺氟沙星残留

构建了乙醇-正丙醇-磷酸二氢钠(NaH2PO4)多元混合双水相体系萃取/检测环境水样中的诺氟沙星,讨论了醇的用量、盐的种类及浓度、pH值、温度对诺氟沙星分配行为的影响,并采用响应曲面法(Response surface methodology,RSM)对实验条件进行优化.结果表明,在乙醇与正丙醇加入量为4 mL(体积比...     

硫酸铵-3，5-二溴水杨基荧光酮-乙醇体系萃取分离钼

在含有一定浓度硫酸铵的条件下,乙醇水溶液能形成盐水与乙醇液-液两相,研究了Mo(Ⅵ)与3,5二溴水杨基荧光酮(DBSAF)形成的配合物在乙醇盐水萃取体系液-液两相中的分配行为.试验表明,在PH 1～6范围内,硫酸铵浓度为350 g·L-1,试液中乙醇与水的体积比为3比7,1×10-4mol·L-1 DBSAF溶液加入量为2 mL及试液总体积为10 mL的条件下,Mo(Ⅵ)均保持很高的萃取率,用控制酸度的方法实现了Mo(Ⅵ)与常见过渡元素离子Co(Ⅱ)、Zn(Ⅱ)、Ni(Ⅱ)、Cu(Ⅱ)、Mn(Ⅱ)、Fe(Ⅲ)、W(Ⅵ)的定量分离,试验了钼(Ⅵ)与上述各共存离子的分离,钼(Ⅵ)的萃取率均大于97%,而其他共存离子的萃取率均小于5%.     

离子液体萃取-火焰原子吸收光谱法测定地表水中微量锌

合成了离子液体1-丁基-3-甲基咪唑六氟磷酸盐([Bmim]PF6),并将其用于水样中锌的萃取。在500 mL水样中依次加入10 g.L-1EDTA溶液3 mL和离子液体5 mL,在pH 7左右的条件下振摇5 min,分出离子液体相,用1.0 mol.L-1盐酸溶液10 mL返萃取,于水相中火焰原子吸收光谱法测定其锌量。锌的质量浓度在0.005～0.02 mg.L-1范围内与吸光度呈线性关系,方法的检出限(3σ)为0.75μg.L-1。应用此法测定地表水中锌,回收率在85%～110%之间。     

新型功能化离子液体的合成及液-液萃取钕(Ⅲ)的研究

研究了新型功能化离子液体1-戊基-3-(3-乙基苯基膦酰基)丙基咪唑双(三氟甲基磺酰基)亚胺盐的合成及对Nd(Ⅲ)的萃取性能,考察了水相酸度、萃取时间、杂质离子等对萃取性能的影响。结果表明,在0.13g该离子液体中,萃取时间为30min,5 mL pH 9.0的Nd(Ⅲ)溶液浓度在0.1～5.0μg/mL时,其线性回归方程为Y=-29352+2.423×106ρ(μg/mL),线性相关系数和最低检测限分别为0.9982和0.0025μg/mL。同时研究了离子液体的回收利用,在5%HNO3介质中洗脱30 min,Nd(Ⅲ)洗脱率达86%以上,回收后的离子液体可再利用。     

离子液体[Emim]PF6-邻菲咯琳萃取回收废旧电池中镐、镍离子的研究

研究了疏水性离子液体[Emim] PF_6-邻菲咯琳萃取体系对废旧镍镉电池中镉、镍离子的萃取性能,考察了振荡时间、温度、平衡水相酸度和萃取剂用量时萃取性能的影响.在水相pH值为5.91、温度为80℃时,4.0mL4g/L的邻菲咯琳与3.0mL离子液[Emim] PF_6组成的萃取体系时废旧电池液中镉、镍离子萃取效果良好.同时研究了废旧离子液在不同时间及酸度下的反萃效果,在浓度为1.0mol/L的盐酸介质中反萃1h,镉、镍离子能较好地被反萃.     

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.