氧化石墨烯表面新型磁性四溴双酚A印迹复合材料的制备及吸附性能

以二氧化硅包覆的磁性氧化石墨烯为载体, 利用热聚合方法制备了对四溴双酚A(TBBPA)有特异吸附效果的新型磁性印迹复合材料. 采用透射电子显微镜(TEM)、 扫描电子显微镜(SEM)、 傅里叶变换红外光谱(FTIR)、 热重分析(TGA)和样品振动磁强计(VSM)对该印迹复合材料进行了表征. 结果表明, 在氧化石墨烯表面制备了一层厚度为55~65 nm、 热稳定良好的磁性印迹层. 结合磁固相萃取技术(M-SPE)和高效液相色谱(HPLC)检测技术研究了该磁性印迹复合材料对四溴双酚A的吸附行为, 结果表明该印迹复合材料对四溴双酚A具有良好的选择吸附能力, 最大吸附量为16.33 mg/g. 结合HPLC检测技术, 该印迹复合材料可用于分离富集饮用水中的四溴双酚A.     

磁性碳纳米管表面新型壬基酚印迹纳米复合材料制备及吸附性能

采用聚苯胺包覆的磁性多壁碳纳米管为载体,以壬基酚(NP)为模板分子,甲基丙烯酸(MAA)为功能单体,乙二醇二甲基丙烯酸酯(EGDMA)为交联剂制备新型磁性壬基酚印迹复合萃取材料。 采用扫描电子显微镜(SEM)、红外光谱(FT-IR)和样品振动磁强计(VSM)等技术手段对该磁性印迹复合材料进行表征和分析,结果表明,在磁性碳纳米管表面成功接枝厚度为60~70 nm的印迹聚合层。 采用高效液相色谱(HPLC)技术对该印迹复合材料的吸附性能进行探讨,结果表明,该磁性印迹复合材料对壬基酚具有特异性吸附性能,最大吸附量为38.46 mg/g。 结合HPLC检测技术,该磁性印迹复合材料成功用于分离富集饮用水中的壬基酚。     

磁性双酚A分子印迹材料的制备及性能研究

采用沉淀法制备了Fe_3O_4磁性微球,以硅烷化试剂对其表面改性后作为载体,以双酚A为模板分子,甲基丙烯酸为功能单体,N,N′-亚甲基双丙烯酰胺为交联剂,采用乳液聚合法制备了对BPA有特异吸附性能的磁性分子印迹材料(MMIPs)。此材料具有较强的磁性和对双酚A的吸附性,可以在外加磁场的条件下方便实现水中双酚A的富集分离。溶液中双酚A的质量浓度为60mg·L~(-1)时,制备的磁性MIPs材料对双酚A饱和吸附量为22.06mg·g~(-1),60min达到吸附平衡。     

三聚氰胺磁性印迹固相萃取材料的制备及其应用

采用磁性氧化石墨烯(GO)为载体,三聚氰胺(MEL)为模板分子,甲基丙烯酸(MAA)为功能单体,乙二醇二甲基丙烯酸酯(EGDMA)为交联剂,制备了新型三聚氰胺磁性印迹聚合物。 采用扫描电子显微镜(SEM)、透射电子显微（TEM）、差热分析(TG)和样品振动磁强计(VSM)对该磁性印迹聚合物进行表征和分析,结果表明,在氧化石墨烯表面成功制备磁性印迹聚合物。 结合高效液相色谱分析技术对该印迹聚合物的吸附性能进行检测,结果表明,该磁性印迹聚合物对三聚氰胺表现出特异性吸附性能,最大吸附容量为33.11 mg/g;相对于环丙氨嗪和三聚氰酸,三聚氰胺的选择因子(β)分别是2.43和2.84。 结合磁固相萃取与液相色谱检测技术,实现了牛奶样品溶液中三聚氰胺的分离、富集和检测。     

多壁碳纳米管表面对硝基苯酚印迹复合材料的制备与吸附性能

以多壁碳纳米管表面接枝的L-苯丙氨酸为结合位点, 甲基丙烯酸为功能单体, 乙二醇二甲基丙烯酸酯为交联剂, 采用沉淀聚合技术, 在碳纳米管表面制备了对硝基苯酚印迹复合材料. 采用红外光谱和扫描电镜研究了该印迹复合材料的结构和形貌, 结果表明, 在碳纳米管表面接枝了一层稳定的印迹材料. 采用高效液相色谱研究了该印迹材料的等温吸附性能, 结果表明, 该印迹材料对模板分子具有较大的吸附容量(Qmax=80.5 μmol/g)和良好的选择吸附性能(选择因子达2.5). 以该印迹材料作为固相萃取吸附剂, 研究了它对对硝基苯酚和其它结构类似物混合溶液的动态吸附性能, 结果表明, 印迹复合材料对对硝基苯酚的吸附容量不受结构类似物浓度的影响, 能较好地应用于对硝基苯酚的分离富集检测.     

表面印迹聚合物萃取/气相色谱质谱联用检测双酚A

以双酚A(BPA)为模板分子,甲基丙烯酸为单体,乙二醇二甲基丙烯酸酯作为交联剂,在硅胶表面合成双酚A分子印迹聚合物。通过红外光谱、比表面积测定等对表面印迹聚合物进行分析和表征;采用静态吸附法和动态吸附法对其吸附性能进行考察。红外光谱表明硅胶表面生成了对模板分子具有识别功能的官能团;热重分析证明该印迹聚合物具有良好的热稳定性;静态吸附实验说明表面印迹聚合物比非印迹聚合物具有良好的吸附性能,该印迹聚合物对双酚A最大吸附容量Q max为1.501 mg/g,吸附速率常数k为0.01586g/(mg·min)。用表面印迹聚合物萃取(MISPE)和气相色谱质谱(GC-MS)联用检测了BPA样品,BPA的回收率接近90%,并将该双酚A表面印迹聚合物用于牛奶样品中的BPA测试,结果表明该印迹聚合物具有较好的吸附选择性。     

乙草胺磁性分子印迹聚合物的制备及其应用

以γ-(甲基丙烯酰氧)丙基三甲氧基硅烷(KH-570)改性的Fe_3O_4纳米粒子为载体,以乙草胺(acetochlor)为模板分子,采用表面分子印迹技术制备乙草胺磁性分子印迹聚合物(Fe_3O_4@SiO_2@MIP)。通过红外光谱和扫描电镜对聚合物的结构和形貌进行表征;通过高效液相色谱(HPLC)检测技术考察磁性印迹聚合物的吸附性能。结果表明,该印迹聚合物对乙草胺具有良好的选择识别能力,其最大吸附量为86.61 mg·g~(-1),并将其作为固相萃取剂成功应用于稻田水中乙草胺的分离、富集。     

分子印迹空心球在蛋白质固相萃取中的应用

建立了分子印迹固相萃取-高效液相色谱相结合分离复杂样品中牛血红蛋白(Hb)的方法. 以单分散的二氧化硅球为载体, Hb为模板, 采用表面印迹法制备了分子印迹空心球(MIHS). 采用透射电子显微镜(TEM)对该印迹材料的形貌进行了表征. 结果表明, 所制备的MIHS的单分散性好、 粒径均匀, 是一种理想的固相萃取填料. 以该印迹材料作为固相萃取吸附剂, 并结合高效液相色谱(HPLC)研究了其对Hb的吸附行为, 结果表明, 制备的MIHS在磷酸盐缓冲液(pH=7.0)中对Hb的回收率高于80%, 而对核糖核酸酶A(RNase A)和细胞色素C(Cyt C)的回收率低于50%, 方法的精密度高(RSD<5%). 与Hb印迹硅球相比, MIHS具有较快的传质速率和萃取效率. 将MHIS应用于复杂样品中Hb的分离, 结果表明, MIHS可以从加标牛血清中选择性吸附Hb, 吸附率达82%.     

分子印迹磁性固相萃取/液相色谱法检测奶制品中的双酚A

以双酚A(BPA)为模板分子,磁性二氧化硅(Fe_3O_4@SiO_2)为载体,4-乙烯基吡啶(4-VP)为功能单体,采用表面分子印迹技术制备了双酚A磁性分子印迹聚合物微球(Fe_3O_4@SiO_2-MIPs)。通过红外光谱、透射电镜等对Fe_3O_4@SiO_2-MIPs进行了结构和形貌的表征。将制得的Fe_3O_4@SiO_2-MIPs作为磁性吸附剂,分离富集奶制品中的BPA,建立了分子印迹磁性固相萃取/液相色谱法测定奶制品中BPA的新方法。结果表明,在优化条件下,Fe_3O_4@SiO_2-MIPs对BPA具有良好的选择性,最大吸附容量达13.50 mg/g,在0.05~5.0 mmol/L浓度范围内有良好的线性关系(r2=0.993 4),方法检出限为0.037μg/L,样品加标回收率为86.2%~93.1%,相对标准偏差为2.9%~3.8%。该方法高效快速,选择性好,可用于牛奶样品中痕量BPA的检测。     

多壁碳纳米管表面邻苯二甲酸二(2-乙基)己酯印迹聚合物的制备及其在固相萃取中的应用

以苯基修饰的多壁碳纳米管为载体,邻苯二甲酸二(2-乙基)己酯为模板分子,甲基丙烯酸为功能单体,乙二醇二甲基丙烯酸酯为交联剂,在碳纳米管表面接枝一层塑化剂邻苯二甲酸二(2-乙基)己酯印迹聚合层.采用红外光谱和扫描电镜对聚合物进行表征和分析.结果表明,在碳纳米管表面成功接枝一层20～30 nm厚的印迹聚合层.采用高效液相色谱研究该印迹聚合物的吸附性能,结果表明,碳纳米管分子印迹聚合物对邻苯二甲酸二(2-乙基)己酯最大吸附量为69.1 μmol/g,达到吸附平衡时间约为60 min.选择性吸附实验表明,与其它结构类似物相比,该印迹复合材料对邻苯二甲酸二(2-乙基)己酯有良好的识别能力.作为固相萃取材料装填于固相萃取柱中,该印迹聚合物能对芒果汁样品中塑化剂进行有效的分离和富集.     

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.