孔雀石绿磁性印迹聚合物的制备及其分离应用研究

以Fe3O4作为磁性载体包覆二氧化硅,并通过表面修饰引入碳碳双键,然后采用分子印迹技术,以孔雀石绿为模板分子,α-甲基丙烯酸和4-乙烯基吡啶作为双功能单体,乙二醇二甲基丙烯酸脂为交联剂,通过偶氮二异丁腈引发制备孔雀石绿的磁性印迹聚合物(MMIPs)并对单体和模板分子比例进行优化;分别采用红外光谱(FTIR)、振动样品磁强计(VSM)和透射电子显微镜(TEM)等仪器分析手段,对MMIPs的物理性质及结构进行表征;采用平衡吸附、动力学吸附和选择性吸附实验考察了材料对孔雀石绿的特异性识别能力;运用Scatchard分析,模拟得出磁性印迹聚合物具有两类不同的结合位点,其解离常数分别为1.469 mg/L和8.518 mg/L,对孔雀石绿的最大表观吸附量分别为2.97 mg/g和6.02 mg/g;将该材料应用在鱼肉样品中孔雀石绿及其代谢物隐色孔雀石绿的分离富集,经过对提取液的磁性固相萃取,在低浓度下(2,5,10μg/kg),孔雀石绿和隐色孔雀石绿的样品加标回收率都在合理范围内。     

烯基离子液体为单体的磁性分子印迹聚合物及其用于酚类化合物的萃取和检测

以3-(甲基丙烯酰氧)丙基三甲氧基硅烷修饰的Fe3O4为载体,乙二醇二甲基丙烯酸酯为交联剂,4-硝基苯酚为模板分子,烯基离子液体1-乙烯基-3-乙基咪唑四氟硼酸盐为功能单体制备了磁性分子印迹聚合物(IL-MMIP),采用透射电镜、红外光谱和磁强计对磁性分子印迹聚合物进行表征,结果表明磁性载体表面成功地包覆了分子印迹聚合物层。IL-MMIP对4-硝基苯酚的吸附在10 min达到平衡,最大饱和吸附量达到20.98μmol/g。对比磁性非印迹聚合物,IL-MMIP对4-硝基苯酚具有较高的选择吸附性能。IL-M M IP萃取-高效液相色谱法对4-硝基苯酚、2-硝基苯酚、苯酚、间甲酚等4种酚类化合物进行检测,检测限在0.2~1.7μg/L。方法应用于自来水、嘉兴南湖水、焦化厂废水等实际样品中酚类化合物的检测,加标回收率在85.7%~100.5%。     

磁性氧化石墨烯壬基酚分子印迹聚合物的制备及吸附性能研究

以磁性氧化石墨烯(Fe3O4@GO)为载体,2-乙烯基吡啶为功能单体,乙二醇二甲基丙烯酸酯为交联剂,利用表面聚合技术制备了对壬基酚(NP)有特异吸附性能的分子印迹聚合物。电子显微镜表征和静态吸附试验结果表明:分子印迹聚合物已修饰在Fe3O4@GO表面,且该聚合物对壬基酚有良好的吸附性能,其最大吸附量为27.99g·kg~(-1)。以该分子印迹聚合物为固相萃取材料,乙腈为上样溶剂、甲醇-乙酸(9+1)溶液为洗脱剂,采用高效液相色谱法对牛奶塑料包装袋中壬基酚进行富集和测定。NP质量浓度的线性范围为2.0~100μg·L~(-1),检出限(3S/N)为0.34μg·kg~(-1)。加标回收率在86.1%~95.2%之间,测定值的相对标准偏差(n=5)小于5.0%。     

表面定向磁性印迹聚合物的制备及对槲皮素的选择性识别

利用硼酸功能化的磁性碳纳米管作为反应基质, 采用一种简便、 绿色的硼酸亲和表面定向印迹法制备了槲皮素磁性分子印迹聚合物, 并将其应用于银杏叶提取物中槲皮素的特异性识别. 透射电子显微镜、 X射线光电子能谱仪、 X射线衍射及振动样品磁强计测试结果表明, 制备的分子印迹聚合物具有良好的形貌和晶型结构. 吸附实验结果表明, 该分子印迹聚合物对模板分子槲皮素具有较好的吸附容量(4.57 μg/mg)、 良好的印迹效果(IF=8.44)和再生能力. 对实际中药样品银杏叶提取物的吸附实验结果表明, 所建立的方法能达到预期的槲皮素检测效果, 可作为中药有效成分槲皮素的特异性识别工具.     

核-壳型磁性灭草隆分子印迹聚合物的制备及其吸附性能研究

以二氧化硅修饰的四氧化三铁为载体,灭草隆为模板分子,采用表面印迹技术制备了核-壳结构的磁性灭草隆分子印迹聚合物(Fe3O4@SiO2-MIPs)。采用扫描电镜(SEM)和磁强计(VSM)对产物的结构进行了表征。通过静态平衡结合法研究了磁性分子印迹聚合物的吸附能力、选择性。结果表明,与磁性非分子印迹聚合物相比,磁性分子印迹聚合物对灭草隆具有高选择性和高特异性吸附,最大吸附量80μmol g-1;Scatchard分析表明,印迹聚合物存在两类不同的吸附结合位点,Langmuir模型可以很好拟合吸附等温线,其相关系数R2=0.9989。     

基于硼酸基功能化的磁性表面印迹聚合物制备及其对目标糖蛋白的识别

以硼酸基功能化的磁性Fe3O4纳米粒子(Fe3O4NPs)为载体,卵清蛋白(OB,一种糖蛋白)作模板分子,多巴胺(DA)为单体,采用表面印迹的方法,制备了一种磁性表面分子印迹聚合物纳米粒子。用平衡吸附实验研究了其吸附性能和识别选择性。结果表明,该分子印迹聚合物对目标糖蛋白(OB)具有较高的选择性和吸附量,并且具有良好的磁性,有利于进行快捷的磁性分离,这将为复杂生物样品中目标糖蛋白的专一性识别提供一种新的途径。     

谷胱甘肽磁性分子印迹聚合物的制备及吸附性能研究

采用表面分子印迹技术,以谷胱甘肽（GSH）为模板分子,N-乙烯基吡咯烷酮（NVP）和丙烯酰胺（AM）为功能单体,N,N’-亚甲基双丙烯酰胺（MBA）为交联剂,γ-（甲基丙烯酰氧）丙基三甲氧基硅烷（KH570）改性的Fe₃O₄纳米颗粒为磁性载体,制备了对GSH有特异识别性的磁性分子印迹聚合物（GSH-MMIPs）. 利用X射线衍射仪（XRD）、透射电子显微镜（TEM）、红外光谱（FT-IR）和振动样品磁强计（VSM）对聚合物进行了表征,结果表明磁性载体表面成功地包覆了分子印迹聚合物薄层. 静态吸附平衡实验和Scatchard分析结果表明,GSH-MMIPs中存在两类不同的结合位点,平衡解离常数分别为8.786×10^-4 mol/L和5.424×10^-3 mol/L,最大吸附量分别为49.195 mg/g和155.003 mg/g. 与化学组成相同的磁性非印迹聚合物（GSH-MNIPs）相比,GSH-MMIPs对谷胱甘肽有较高的选择吸附性能.     

4-甲基咪唑磁性表面分子印迹聚合物的制备及其应用

以4-甲基咪唑(4-MI)为模板分子,甲基丙烯酸(MAA)为功能单体,利用Fe₃O₄磁性纳米微球制备了具有特异性识别能力的磁性表面分子印迹聚合物(MIP),并用红外光谱(FT-IR)、X-射线衍射(XRD)、透射电子显微镜(TEM)和振动样品磁强计(VSM)对聚合物进行了表征,结果显示磁性载体表面包覆了分子印迹聚合物薄层。用紫外分光光度法对4-MI与MAA的相互作用进行了分析,结果表明主客体主要存在形式为1个4-MI被1个MAA所包围。通过紫外分光光度法对磁性印迹聚合物的吸附性能进行了研究,静态吸附平衡实验和Scatchard分析结果表明Fe₃O₄@(4-MI-MIP)中存在两类不同的结合位点,最大吸附量分别为40.31 mg/g和23.07 mg/g,平衡解离常数分别为64.85 mg/L和30.41 mg/L。动力学研究表明准二级动力学方程能较好地拟合动力学实验结果,该过程符合准二级动力学模型。该磁性印迹聚合物应用于环境水样中4-MI的吸附,取得了较满意的结果。     

三聚氰胺磁性分子印迹聚合物材料的制备及性能表征

利用溶剂热法通过控制反应时间和温度制得了分散性好和磁性强的Fe3O4,并利用溶胶凝胶法制备得到包覆SiO2的磁性微球(Fe3O4@SiO2)。以三聚氰胺为模板分子,甲基丙烯酸(MAA)为单体,采用本体聚合法制备了磁性分子印迹聚合物(MMIPs)。通过静态吸附实验表明,MMIPs对三聚氰胺的饱和吸附量高达10.22μg/mg,是磁性非印迹聚合物(MNIPs)的1.62倍。粒子扩散模型、Elovich模型和动态吸附实验表明所制得的MMIPs有较好的吸附性能。     

磁性表面分子印迹聚合物的合成及其在玉米汁中检测玉米赤霉烯酮的应用北大核心CSCD

本研究以姜黄素为替代模板分子,Fe_(3)O_(4)@SiO_(2)-MPS为磁性载体,采用表面分子印迹技术制备了玉米赤霉烯酮(Zearalenone,ZEN)磁性分子印迹聚合物(ZEN-MMIPs)。使用傅立叶红外光谱(FTIR)、扫描电镜(SEM)、透射电镜(TEM)、振动样品磁强计(VSM)技术对制备的磁性分子印迹纳米微球进行表征。通过吸附动力学和吸附等温线考察了ZEN-MMIPs的吸附性能,其最大吸附容量为0.72 mg/g。以ZEN-MMIPs为磁性分散固相萃取剂,结合高效液相色谱(HPLC)完成了复杂食品基质中ZEN加标样品的痕量检测,线性范围为1~100 mg/L(R^(2)=0.9991),相对标准偏差(RSD)为2.11%,玉米汁样品加标回收率为88.3%~94.7%。本文所建立的方法可用于复杂基质实际样品中ZEN残留的检测。     

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.     

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.     

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.     

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.     

α-Amino acid derived enaminones and their application in the synthesis of N-protected methyl 5-substituted-4-hydroxypyrrole-3-carboxylates and other heterocycles

A new and simple synthesis of novel N-protected methyl 5-substituted-4-hydroxypyrrole-3-carboxylates, which exist in equilibrium with their 4-oxo tautomers, has been developed in two steps starting from N-protected α-amino acids. The key intermediates are enaminones, which can also be isolated, characterized, and used for the construction of other functionalized heterocycles, before they spontaneously decompose to pyrrole products. 4-Hydroxypyrroles are prone to partial aerial oxidation but can be efficiently alkylated or reduced to stable polysubstituted pyrrolidine derivatives.     

Specific intramolecular aromatic CH insertion of diazosulfonamides

The chemoselectivity in the intramolecular CH insertion of various diazosulfonamides has been experimentally studied. The results reveal that the aliphatic 1,4-, 1,5-, or 1,6-C(sp³)?H insertions of diazosulfonamides are not accessible, while the aromatic 1,5-C(sp²)?H insertion can be realized specifically by adjusting the diazo-adjacent group. In addition, the general chemoselectivities in the intramolecular CH insertions of diazosulfonyl compounds are summarized. Generally, diazosulfones undergo both aromatic 1,5-C(sp²)?H and aliphatic 1,5- and 1,6-C(sp³)?H insertions, while diazosulfonates undergo aliphatic 1,5- and 1,6-C(sp³)?H insertions. However, diazosulfonamides only undergo aromatic 1,5-C(sp²)?H insertion.     

Microwave-assisted copper-catalyzed stereoselective ring expansion of three-membered heterocycles with α-diazo-β-dicarbonyl compounds

Microwave-assisted copper-catalyzed ring expansions of three-membered heterocycles with α-diazo-β-dicarbonyl compounds were investigated. Thiiranes generated 3-acyl-5,6-dihydro-1,4-oxathiines in the presence of copper sulfate and trans-3-acyl-5,6-dihydro-1,4-oxathiines as stereospecific products for 1,2-disubstituted cis-thiiranes through an intramolecular S_N2 process. Oxiranes gave rise to 2-acyl-5,6-dihydro-1,4-dioxines under the catalysis of copper hexafluoroacetylacetonate and cis-3-acyl-5,6-dihydro-1,4-dioxines as stereospecific products for 1,2-disubstituted cis-oxiranes via an intimate ion-pair mechanism. The current method provides a direct and simple strategy in efficient preparation of 3-acyl-5,6-dihydro-1,4-oxathiines and 2-acyl-5,6-dihydro-1,4-dioxines, important agents in medicinal and agricultural chemistry, from readily available thiiranes and oxiranes, respectively.     

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.     

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.