络合萃取法处理二甲胺废水

采用络合萃取法处理二甲胺(DMA)废水,考察了萃取剂的种类和用量、溶液pH值、油与水比对二甲胺萃取效果的影响. 实验结果表明,以P204为萃取剂、环己烷为稀释剂时,P204与DMA以1∶ 1形式络合,萃取是一个放热且快速反应过程,反应热ΔH=-6.50 kJ/mol. 在油与水比为1∶ 4、萃取剂稀释剂体积比为1∶ 9、废水pH=11.87的条件下,DMA的一级萃取率为93.0%. P204负载DMA的红外谱图研究表明,P204络合萃取二甲胺同时存在离子缔合成盐机制和氢键缔合机制.     

长链氨羧络合剂萃取稀土饵

研究了长链氨羧络合剂N,N′-二(十二烷基)乙二胺二乙酸钠(Na2R2Y)的氯仿溶液萃取稀土饵的行为;考察了溶液酸度、络合剂浓度、相比和温度对萃取率的影响.用摩尔比法测定了Na2R2Y与Er3+的络合摩尔比为1∶1;结果表明,Na2R2Y的氯仿溶液对饵的萃取率随络合剂浓度的增大而增大,随温度的升高而降低.     

DNNSA反胶团溶液净化磷酸中镁的研究

本文研究了二壬基萘磺酸(DNNSA)形成的微乳萃取磷酸中镁离子的工艺条件.分别考察了稀释剂、萃取时间、萃取剂浓度、温度、磷酸浓度对磷酸中镁离子萃取的影响.结果表明,稀释剂极性越低越有利于萃取,萃取平衡时间为40 min,萃取剂浓度增加有利于萃取,升高温度对萃取有利,磷酸浓度增加萃取率下降.红外光谱分析证实,DNNSA反胶团萃取磷酸中镁离子为阳离子交换机理.     

磷酸三丁酯/正辛醇络合萃取对氯苯酚

以对氯苯酚稀溶液为研究对象,以正辛醇为稀释剂,研究了萃取剂种类及其浓度、水相平衡pH、对氯苯酚初始浓度等因素对萃取分配比的影响,并用NaOH对其负载溶质的有机相进行反萃.结果表明,络合萃取对处理高浓度对氯苯酚废水具有优势;磷酸三丁酯(TBP)的浓度和体系的pH是影响络合萃取的关键因素;采用NaOH对有机相进行反萃,当NaOH浓度为0.5mol/L时反萃率达到98.55%.红外光谱分析表明,TBP萃取对氯苯酚基于氢键作用机理.     

8-羟基喹啉萃取Pr3+，Nd3+的机理探讨

研究了8-羟基喹啉(HQ)从盐酸介质中萃取Pr 3 ,Nd 3 的行为. 通过对Pr 3 ,Nd 3 萃取平衡常数的测定结果发现,8-羟基喹啉对Pr 3 ,Nd 3 的萃取反应具有相近的平衡常数. Kex(Pr 3 )=10 -11.83,Kex(Nd 3 )=10 -11.70. 从稀释剂的种类,水相酸度,萃取剂浓度,Ac -浓度4个方面探讨了8-羟基喹啉萃取Pr 3 ,Nd 3 的机理. 结果显示,Ac -在溶液中分别与Pr 3 ,Nd 3 络合,并以Pr(Ac -) 2 ,Nd(Ac -) 2 的形式参与萃取反应;不同稀释剂随着介电常数的增大,萃取率逐渐变小,萃取率的顺序为:庚烷＞环己胺＞四氯化碳＞二甲苯＞甲苯＞氯仿＞二氯甲烷. 探讨了8-羟基喹啉萃取Pr 3 ,Nd 3 的机理.     

不同稀释剂中HDEHP的界面性质研究

用滴体积法研究了HDEHP在不同稀释剂-0.05mol.dm^-^3(N2, Na2)SO4(pH=2.40)体系中的界面性质, 认为吸附于液-液界面的是单体HDEHP分子, 得到了各体系中HDEHP的Cmin, Tmax, Ai以及△Gad等界面吸附参数。HDEHP在不同稀释剂体系中的界面活性顺序为: 脂肪烃>芳香烃>氯仿>甲基异丁基酮, 这种变化主要是在体相中和界面上稀释剂与萃取剂、界面上的萃取剂及稀释剂与界面层水之间分子间相互作用的结果。同时讨论了HDEHP在不同稀释剂中的萃取动力学机理。     

萃取法去除硫酸氧钛液中杂质铁

采用溶剂萃取法有效去除了钛白粉制备过程中的中间产物硫酸氧钛液中大量的杂质铁。 将硫酸氧钛液中的Fe2+氧化成Fe3+后,用磷酸三丁酯(TBP)和煤油混合体系萃取除去Fe3+。 考察了氧化剂、稀释剂、有机相中TBP体积分数、萃取相比、NaCl加入量等对铁萃取率的影响以及反萃条件的选择和萃取剂的循环使用效果,结果表明,用煤油作稀释剂,TBP在有机相的体积分数为60%,萃取相比O/W为2∶1时,NaCl加入量以Cl-计4 mol/L,Fe3+的3次萃取率可达99%,钛的损失率低至0.4%。当反萃相比W/O为1∶1时,Fe3+的3次反萃率可达100%。TBP经过5次萃取-反萃循环使用后,对Fe3+的萃取率无明显下降,可循环使用。     

离子液体双水相萃取分离苋菜红的研究

建立了由亲水性离子液体四氟硼酸1-丁基-3-甲基咪唑([Bmim]BF4)和NaH2PO4形成的双水相体系萃取分离苋菜红的新方法.研究了盐的浓度、离子液体浓度、溶液酸度、其它共存物质对苋菜红萃取率的影响.结果表明,NaH2PO4加入量在2～2.5 g,离子液量在1.0～2.0 mL,苋菜红溶液量在1.5 mL,溶液酸度在pH 4～6范围,离子液体双水相体系对苋菜红有较高的萃取率(E%＞90).用加入无机离子、不同类型表面活性剂和吸收光谱探讨了离子液体与苋菜红之间的作用.     

三辛胺萃取多元酚的研究

采用三辛胺为络合剂，苯或正辛醇为稀释剂研究了邻苯干分配，间苯三酚稀溶液的萃取相平衡，讨论了稀释剂，溶液ｐＨ值和硫酸钠度对分配系数的影响。确定了萃合物的组成，负载有机相的红外谱图分析表明，三辛胺与酚类的萃取同时存在氢键缔合溶剂化和离子缔合成盐历程。     

α-正十二烷硫基乙酸乙酯的反相纸层析R_f图谱及其对钯的萃取

本文研究了α-正十二烷硫基乙酸乙酯在盐酸和硝酸体系中的R_f图谱,对四十多种金属离子进行反相纸层析,初步确定对钯具有优异的萃取性能,并用液-液萃取法研究了稀释剂和酸度对萃取钯的影响,测定了萃取络合物的组成为PdCl_2·2ELTA,探讨了萃取机理。     

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.