悬浮聚合法合成马拉硫磷分子印迹聚合物的吸附性能研究

基于分子印迹技术,采用悬浮聚合的方法,合成了马拉硫磷分子印迹聚合物。通过优化,确定最佳合成条件为:模板分子(马拉硫磷)∶功能单体(α-甲基丙烯酸)为1∶8,模板分子(马拉硫磷)∶交联剂(乙二醇二甲基丙烯酸酯)为1∶40,温度60℃,引发剂用量为1.0%。吸附性能测试结果表明,印迹聚合物对马拉硫磷的最大吸附量为4.62μg/mg,而非印迹聚合物对马拉硫磷的最大吸附量为2.21μg/mg;通过选择性实验得到印迹聚合物对灭线磷、甲拌磷、特丁硫磷、乐果、马拉硫磷、克线磷的吸附量分别为3.87、3.75、3.57、4.00、4.44、3.61μg/mg,而非印迹聚合物的吸附量分别为1.42、1.37、1.30、1.43、1.12、1.23μg/mg。     

氯胺酮分子印迹聚合物的制备与性能研究

为了制备对氯胺酮具有选择性识别能力的分离富集材料,实验采用本体聚合法,以氯胺酮为模板,(-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,在优化了功能单体与交联剂的用量后,制备了一种吸附性能理想的分子印迹聚合物。该印迹聚合物在氯胺酮浓度为100μg·m L~(-1)的甲醇溶液中对氯胺酮的吸附量为33.8 mg·g~(-1),印迹因子为2.02,而且可以再生与重复使用。     

不同功能单体合成的分子印迹聚合物识别性能的研究

采用分子印迹技术,用不同的功能单体合成了槲皮素的分子印迹聚合物,测定了它们的吸附性能,并考察了模板分子与功能单体相互作用与印迹聚合物吸附性能的关系。结果表明:在四氢呋喃-氯仿(V/V 8:2)的溶剂体系中以2-乙烯基吡啶(2-VP)为功能单体合成的分子印迹聚合物的吸附性能最强,吸附量为4457.52(μg)/g,通过紫外光谱法测定的结果,在该条件下槲皮素与2-乙烯基吡啶的作用力也是较强的。     

DNOP磁性分子印迹聚合物的制备及其表征

以磁性Fe_3O_4为载体,邻苯二甲酸二正辛酯(DNOP)为模板,α-甲基丙烯酸为单体,乙二醇二乙基丙烯酸酯为交联剂,偶氮二异丁腈为引发剂,通过悬浮聚合的方法制备了DNOP磁性分子印迹聚合物。通过红外光谱和扫描电镜等对聚合物的结构和形态进行了表征,结合气相色谱(GC-FID检测器)技术考察了磁性印迹聚合物对DNOP的吸附性能。通过正交实验表明,当反应在70℃、模板:单体:交联剂=1∶6∶30、引发剂占单体和交联剂总质量的2.5%的条件下,该磁性印迹聚合物对DNOP的饱和吸附量为1.82 mg g~(-1)。等温吸附实验表明,该磁性分子印迹聚合物对DNOP有较好的吸附性能。     

印迹5,7-二羟基黄酮聚合物的合成及其性能研究

以5,7-二羟基黄酮为模板分子,用沉淀聚合法合成印迹聚合物,采用紫外光谱法测定聚合物对模板分子的吸附量。实验结果表明,随着模板分子浓度增加,吸附趋于饱和;当浓度恒定,吸附时间达到40min时吸附基本达到平衡。制备的印迹聚合物对5,7-二羟基黄酮的吸附量为1．941μmol／g,存在特异性吸附。     

苏丹红Ⅰ分子印迹聚合物制备及吸附性能研究

以苏丹红Ⅰ为模板分子,α-甲基丙烯酸为功能单体,乙二醇二甲基丙烯酸酯为交联剂,偶氮二异丁腈为引发剂,在氯仿中采用沉淀聚合法制备了分子印迹聚合物.聚合物的平衡结合试验表明:模板分子/功能单体/交联剂的摩尔比为1:4:16时所得的印迹聚合物对苏丹红Ⅰ吸附量最大;合成时溶剂和引发剂用量对聚合物吸附量有很大影响;印迹和非印迹聚合物对苏丹红Ⅰ的平衡吸附量分别为49.17μmol·g-1和22.6μmol·g-1,选择性结合试验中印迹聚合物对苏丹红Ⅰ和苏丹红Ⅲ的吸附量分别为26.8μmol·g-1和5.26μmol·g-1,说明印迹聚合物对苏丹红Ⅰ具有特异性吸附;Scatchard分析表明该印迹聚合物具有两类结合位点.     

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。     

米诺地尔分子印迹聚合物的制备与吸附性能

以吸附量为评价指标,筛选米诺地尔分子印迹聚合物的合成条件。结果表明,制备该聚合物的较佳反应条件是V_(甲醇)/V_(乙腈)=1∶3为致孔剂、a-甲基丙烯酸(MAA)为功能单体、n_(米诺地尔)/n_(MAA)/n_(交联剂)=1∶6∶20,采用筛选出的合成条件制备出的分子印迹聚合物,对模板分子有良好的吸附性能。     

溴代-1-甲基-3-己基咪唑离子液体表面分子印迹聚合物的制备及选择性吸附

以聚苯乙烯-二乙烯基苯颗粒为载体,制备溴代-1-甲基-3-己基咪唑离子液体表面印迹聚合物;通过扫描电镜、红外光谱、紫外光谱、比表面积及热分析等手段,对聚合物进行表征;静态实验结果显示,聚合物对模板底物有较强的吸附能力,印迹和非印迹聚合物对模板底物的饱和吸附量分别为667和322μmol g~(-1);动力学实验表明,印迹聚合物在1.0 h内能够达到吸附平衡,其吸附特征符合假二级动力学方程;选择性实验表明,印迹聚合物能够从结构类似物中选择性吸附模板分子。     

手性药物(S)-布洛芬氢键自组装印迹聚合物识别机理

以含有单一结合基团的手性药物(S)-布洛芬作为模板分子,制备了系列印迹聚合物.采用紫外-可见光谱和红外光谱对印迹及识别机理进行了研究.结果表明,模板分子与功能单体分别通过形成蓝移氢键和红移氢键完成预组装过程和再识别吸附过程,且形成了主客体配比为1∶1的配合物.等温吸附实验结果表明,印迹聚合物对模板分子表现出明显的选择性吸附,特异性吸附容量为37.92μmol/g,印迹指数为3.06,且印迹聚合物内特定的三维空间结构对其特异性吸附性能具有显著影响.由手性分离实验考察了印迹聚合物的拆分性能,其对(R)-布洛芬的分离因子为1.79.     

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.     

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.     

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.     

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.     

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.     

N-Heterocyclic carbene-palladacyclic complexes: synthesis,characterization and their applications in the C-N coupling and α-arylation of ketones using aryl chlorides

N-Heterocyclic carbene-palladacyclic complexes 3 were successfully achieved in a one-pot procedure under mild conditions. The structure of 3a was unambiguously confirmed by X-ray single crystal diffraction and it was an active catalyst in the Buchwald-Hartwig amination and α-arylation of ketones even at very low catalyst loadings (0.01?mol%).