甲苯一步催化硝化制备二硝基甲苯反应过程及危险性

采用冷冻辅助-溶胶凝胶法制备了CuMnCoO₄三金属尖晶石氧化物，并对其结构性质进行了XRD、BET、FTIR、Raman、XPS等表征，进一步研究了该尖晶石在无硫酸条件下以硝酸为硝化剂的甲苯无溶剂硝化的催化行为。结果表明，CuMnCoO₄尖晶石催化的甲苯硝化体系对二硝基甲苯(DNT)生成具有偏好性，DNT的选择性比不含尖晶石的甲苯硝化体系高1.6倍。在此基础上，根据“替代、缓和、简化”的本质安全基本原则对传统DNT两段式硝-硫混酸硝化法生产工艺进行优化，得到最佳工艺条件：95%HNO3、甲苯、CuMnCoO₄尖晶石催化剂的摩尔比为4∶1∶0.15，室温下滴加甲苯，结束后保持50℃反应6h，可实现甲苯一步硝化制备DNT (选择性可达67.44%)。通过全自动反应量热仪(RC1e)测试了半间歇反应下，CuMnCoO₄尖晶石催化甲苯硝化过程的热危险性参数，考察了反应过程危险性，发现了该新型多相催化体系在提高DNT选择性的同时，也降低了热失控条件下工艺合成反应可达到的最高温度(MTSR)，从而提高了反应体...     

芳烃甲苯的催化选择性硝化

研究分子印迹聚合物催化剂在甲苯二氧化氮硝化反应的催化特性.应用酸性基团的聚合物单体制得的MIP具有较好的催化性能,在乙腈溶剂中甲苯二氧化氮硝化反应区域选择性达到90%以上.     

交联聚苯乙烯微球负载N-羟基邻苯二甲酰亚胺催化剂对甲苯和环己醇氧化的催化性能

通过分子设计,以交联聚苯乙烯(CPS)微球为基质,制备了固载化的N-羟基邻苯二甲酰亚胺(NHPI)催化剂. 先将CPS微球氯甲基化,制得氯甲基化微球CMCPS,再使微球表面的氯甲基与偏苯三酸酐(TMA)分子中的羧基酯化反应,将邻苯二甲酸酐(PA)键合到聚合物微球表面,获得键合邻苯二甲酸酐的微球CPS-PA,使之与盐酸羟胺反应,制备固载NHPI的微球CPS-NHPI,固载量达2.25 mmol/g,并对其进行表征. 将CPS-NHPI分别用于分子氧氧化甲苯和环己醇过程,考察微球的催化活性,分析其催化氧化机理. 结果表明,以三乙胺为缚酸剂,采用极性溶剂N,N-二甲基乙酰胺,在110℃下CMCPS表面的氯甲基与TMA可顺利反应. 适宜条件下CMCPS氯甲基的转化率可达73%. CPS-NHPI-Co(OAc)2催化体系对分子氧氧化甲苯和环己醇的催化活性良好,为自由基链反应机理.     

分子印迹磁性固相萃取/GC-MS法检测大米中三环唑

以表面分子印迹技术合成了三环唑的磁性分子印迹聚合物微球(Fe_3O_4@SiO_2-MIPs),建立了分子印迹磁性固相萃取/GC-MS法检测大米中三环唑的新方法。结果表明,在优化条件下Fe_3O_4@SiO_2-MIPs对三环唑有良好选择性,在0.050-8.0 mg·L~(-1)浓度范围内线性关系良好(r~2=0.9937),样品加标回收率86.31%97.69%,相对标准偏差小于5%。该方法高效快速、选择性好,可用于大米中痕量三环唑的检测。     

2,2＇,6，6’-四硝基-4，4’-二（三氟甲基）联苯的合成

以对氯三氟甲苯为原料,经硝硫混酸硝化得到3,5-二硝基对氯三氟甲苯,3,5-二硝基对氯三氟甲苯在铜粉催化下经Ullmann偶联反应得到2,2’,6,6’-四硝基-4,4’-二（三氟甲基）联苯。硝化反应收率为93％;偶联反应的优化条件为：以甲苯为反应介质,m（C6H2C1CF3N204）：m（Cu）=1：0．25,110℃反应1．5h,偶联反应收率达73％以上。总收率可达68％。     

基于沉淀聚合法的甲苯分子印迹聚合物的合成与表征

以甲苯为溶剂,利用沉淀聚合法制备了甲基丙烯酸-甲苯-二乙烯苯分子印迹微球。采用红外光谱仪表征产物结构、激光粒度仪表征产物粒径、扫面电镜表征产物表面形貌。结果表明,以偶氮二异丁腈(AIBN)作为引发剂,MAA:DVB=1:3时将聚合温度控制在60℃、磁子转速控制在200 r/min时,可得到形貌规整的印迹聚合物微球。     

胆固醇分子印迹聚合微球的制备及其吸附性能

以胆固醇为模板分子、甲基丙烯酸为功能单体、乙二醇二甲基丙烯酸酯为交联剂,在甲苯-乙腈(9:1, j)混合溶剂中沉淀聚合制备了分子印迹聚合物微球. 采用平衡结合法和Scatchard模型评价了该聚合微球的结合性,考察了其吸附行为. 结果表明,胆固醇分子印迹聚合微球中形成两类不同的结合位点,得到高亲和性结合位点的离解常数和最大表观吸附量分别为0.86 mmol/L和80.4 mmol/g,低亲和性结合位点解离常数和最大表观吸附量分别为0.39 mmol/L和61.6 mmol/g. 此方法合成的分子印迹微球对胆固醇有较好的结合性能,可用于胆固醇的分析检测.     

氧氟沙星印迹微球的制备及条件优化

文章采用悬浮聚合的方法合成氧氟沙星印迹微球,以氧氟沙星(模板分子)∶苯乙烯(功能单体)∶α-甲基丙烯酸(功能单体)∶二乙烯基苯(交联剂)摩尔比为1∶40∶40∶50,偶氮二异丁腈为1.5%,反应温度为80℃,反应时间为8 h。在最优条件下合成的印迹微球的吸附量为5.43mg.g-1,非印迹微球的吸附量为2.92 mg.g-1,印迹微球吸附性明显优于非印迹微球。     

温敏印迹硅胶微球对薯蓣皂素的吸附及控制释放

研究分子印迹聚合物对特定药物的吸附及控制释放具有重要理论和应用价值。本文以硅胶为载体,先对其进行硅烷化修饰,再以薯蓣皂素为模板分子,以甲基丙烯酸（MAA）和N-异丙基丙烯酰胺（NIPAm）为共同功能单体、乙二醇二甲基丙烯酸酯（EGDMA）为交联剂、偶氮二异丁腈（AIBN）为引发剂,通过表面接枝分子印迹聚合物制备了薯蓣皂素温敏印迹硅胶微球。用傅里叶红外光谱及扫描电镜对聚合物表面化学基团及颗粒形貌进行表征。测试了分子印迹硅胶微球的载药性及在不同环境条件下的药物释放行为。结果表明,温敏印迹硅胶微球对薯蓣皂素具有良好吸附性能,其饱和吸附量为21.6mg/g,也具有较高的控制缓释性能。释放动力学表明,其在12h内控制薯蓣皂素释放率为81.9%,而非印迹硅胶微球不具备缓释性。环境条件对温敏印迹硅胶微球的控制释放具有重要影响。当温度为30℃、溶剂为甲醇、NaCl离子强度为1.5×10^-4mol/L时,印迹微球具有最高释放率,达99.28%。     

红霉素分子印迹聚合物纳米微球的制备及其吸附特性

以红霉素为模板分子、甲基丙烯酸为功能单体、乙二醇二甲基丙烯酸酯为交联剂,采用沉淀聚合法制备了粒径均一的红霉素纳米分子印迹聚合物微球,优化了分子印迹聚合物的合成条件,确定了模板分子与功能单体的最佳摩尔比为1:3,对其进行了表征. 结果表明,所制聚合物对红霉素的实际最大吸附量可达202.12 mg/g,吸附约200 min达到平衡,对红霉素具有良好的选择性吸附能力.     

Characterization and quality assessment of binding properties of the monocrotophos molecularly imprinted microspheres prepared by precipitation polymerization in toluene

To obtain the desired specific adsorbents for monocrotophos (MCP) to enrichment, separation, and analysis of trace pesticides residue in soils and foods, molecularly imprinted polymer microspheres were prepared by precipitation polymerization using MCP, methacylic acid (MAA), ethylene glycol dimethacrylate, azobisisobutyronitrile, and toluene as template, functional monomer, crosslinker, initiator, and porogen, respectively. Computer simulation was employed to demonstrate the mechanism of the interaction between MCP and MAA in toluene. It was found that one MCP was entrapped by two MAAs in toluene through hydrogen bond. The binding properties of MCP in toluene for imprinted microspheres were evaluated by equilibrium rebinding experiments. Scatchard plot analysis revealed that there were two classes of binding sites populated in the imprinted polymer microspheres with dissociation constants of 0.0019 and 0.12 mmol/L, respectively. The specificity of the imprinted microspheres was investigated by binding analysis using MCP and structurally related organophosphorous pesticides. The results indicated that the obtained imprinted microspheres showed a good selectivity for MCP. POLYM. ENG. SCI., 47:1302–1308, 2007. © 2007 Society of Plastics Engineers     

Preparation and characterization of uniform molecularly imprinted polymer beads for separation of triazine herbicides

Uniform molecularly imprinted polymer beads were synthesized by precipitation polymerization for separation of triazine herbicides. A series of imprinted polymers were prepared using ametryn as template and divinylbenzene as crosslinking monomer, in combination with three different functional monomers under different solvent conditions. Under optimized reaction conditions, we obtained uniform molecularly imprinted polymer microspheres that display favorable molecular binding selectivity for triazine herbicides. The imprinted polymer beads synthesized using methacrylic acid as functional monomer in a mixture of methyl ethyl ketone and heptane showed the best results in terms of particle size distribution and molecular selectivity. Compared with nonimprinted polymer microspheres, the imprinted microspheres displayed significantly higher binding for a group of triazine herbicides including atrazine, simazine, propazine, ametryn, prometryn, and terbutryn. For the first time, precipitation polymerization has been used to produce highly uniform imprinted microspheres suitable for affinity separation of triazine herbicides. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Preparation and characterization of monodisperse molecularly imprinted polymer microspheres by precipitation polymerization for kaempferol

A new kind of molecularly imprinted polymer (MIP) microspheres for the selective extraction of kaempferol was prepared by precipitation polymerization using 4-vinylpridine (4-VP) and ethylene glycol dimethacrylate (EDMA) as functional monomer and cross-linker respectively. The synthesis conditions, such as ratios of 4-VP/EDMA and polymerization time were discussed in detail. Results showed that the 2% was the optimal concentration of co-monomers to obtain monodisperse MIP microspheres, the best ratio of 4-VP/EDMA was 1:2, and 24 h was considered as the proper polymerization time. Compared with the MIP agglomeration or coagulum particles, monodisperse MIP microspheres showed the better adsorption capacity: the saturated adsorption capacity of monodisperse MIP microspheres was 7.47 mg g^?1, the adsorption equilibrium could be obtained in 30 min. Finally, the adsorption performances of the optimal MIP microspheres were evaluated by kinetic adsorption, adsorption isotherm, and selective adsorption experiments, which indicated that the adsorption mechanism were chemical single layer adsorption and the separation factor was up to 3.91 by comparing with the structure similar compound (quercetin). The MIP microspheres exhibit prospects in the kaempferol efficient and selective separation.     

A Novel Molecularly Imprinted Core?CShell Chemiluminescence Sensor: Preparation and Pendimethalin Recognition

Novel molecularly imprinted core?Cshell microspheres were synthesized using hollow silica microspheres as the core. Because of the molecularly imprinted core?Cshell microspheres, the effective binding sites at the surface of the shells were sharply increased; and, the recognition capability for template molecules was greatly improved. Based on this, a novel chemiluminescence sensor was established and successfully applied in the detection of trace pendimethalin in foodstuffs. The proposed sensor exhibited excellent selectivity, good sensitivity and simple operation. High throughput sample detection was realized with satisfactory results.     

Preparation,characterization and adsorption performance of molecularly imprinted microspheres for erythromycin using suspension polymerization

BACKGROUND: There are few reports on erythromycin molecularly imprinted polymers (MIPs) used as HPLC stationary phase and solid phase extraction matrices. These imprinted polymers are prepared by bulk polymerization, which is tedious and time‐consuming, and they are irregular and possess poor reproducibility and low binding capacity. In this study, molecularly imprinted microspheres for erythromycin were prepared by aqueous suspension polymerization for the first time. RESULTS: Imprinted microspheres for erythromycin were prepared using suspension polymerization in which 1.5% PVA‐water solution is used as continuous phase, and chloroform solution containing erythromycin, methacrylic acid and crosslinker is used as disperse phase. The composition of disperse phase is optimized, and the optimum molar ratio of erythromycin to methacrylic acid was 1:5. Selectivity analysis revealed that the imprinted microspheres can specifically recognize erythromycin from its structure analogues. The binding mechanism between erythromycin and methacrylic acid was investigated by UV‐Vis spectrophotometry. Adsorption kinetics and the adsorption isotherm of the imprinted microspheres indicate that erythromycin can be adsorbed rapidly by the imprinted microspheres and the maximum theoretical static binding capacity is 128.6110 mg g^?1. The imprinted microspheres were used to extract erythromycin from a milk sample and a high recovery rate was obtained. CONCLUSION: Molecularly imprinted microspheres for erythromycin were uniform and possess high adsorption capacity and excellent selectivity. They are therefore a promising extraction and chromatographic media. Copyright © 2011 Society of Chemical Industry     

Macromolecularly imprinted calcium phosphate/alginate hybrid polymer microspheres with the surface imprinting of bovine serum albumin in inverse‐phase suspension

Macromolecularly imprinted calcium phosphate/alginate hybrid polymer microspheres surface imprinted with bovine serum albumin were prepared in inverse‐phase suspension by introducing the intermixture solutions of bovine serum albumin (BSA) and CaCl₂ in sodium alginate aqueous solution where (NH₄)₂HPO₄ was added beforehand. Morphology of the imprinted microspheres was observed by optical microscopy. Rebinding dynamic and thermodynamic behaviors of surface molecularly imprinted calcium phosphate/alginate polymer microspheres (CP/A SMIPMs) and embedding molecularly imprinted calcium phosphate/alginate polymer microspheres (CP/A EMIPMs) were evaluated. CP/A SMIPMs exhibited significant improvement in equilibrium rebinding capacity (Q_e) and imprinting efficiency (IE), compared to CP/A EMIPMs. The surface of CP/A SMIPMs was more competent to facilitate the migration and re‐assembling of proteins. Surface specific peak and interior specific peak were proposed to describe the characteristics of surface and interior specific rebinding behaviors in rebinding dynamics. The effects of (NH₄)₂HPO₄ addition were investigated in detail, along with the concentration of sodium alginate and CaCl₂ solutions to the rebinding and imprinting property of imprinted microspheres. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

3,5,7,3＇,4＇,5＇-六羟基黄酮分子印迹聚合物制备及性能表征

采用分子印迹技术合成了对3,5,7,3＇,4＇,5＇-六羟基黄酮具有高效选择性的分子印迹聚合物,通过静态吸附的方法,利用Scatchard模型,研究了分子印迹聚合物的特异性识别能力。实验表明,以甲基丙烯酸为功能单体,在甲苯溶剂中聚合得到的分子印迹聚合物对3,5,7,3＇,4＇,5＇-六羟基黄酮具有较大的吸附富集能力和识别特性。其饱和吸附容量达到30.8 mg/g。     

Combinatorial synthesis and screening of uniform molecularly imprinted microspheres for chloramphenicol using microfluidic device

A novel method for combinatorial synthesis and screening of uniform‐size molecularly imprinted microspheres using a microfluidic device is presented, in which a new microfluidic device containing twelve pairs of “” shape microchannels is designed to produce droplets and imprinted microspheres via controlled suspension polymerization. This technique combines molecular imprinting and microfluidic device with the combinatorial chemical approach, allowing rapid screening and optimization of uniform imprinted microspheres. On the example of chloramphenicol (CAP), the imprinted microspheres of CAP were prepared by a combinatorial approach using water with 1.5% polyvinyl alcohol as continuous phase, and ethyl acetate–chloroform (4:1, v/v) as porogenic solvents. Functional monomers methacrylic acid (MAA), 4‐vinylpyridine or acrylamide were screened, and the molar ratio of template molecule to functional monomer was optimized. The results indicate that MAA is the best functional monomer for imprinting of CAP, and when the molar ratio of CAP to MAA is 1:5, the imprinted microspheres exhibit the best imprinting performance, and have good monodispersity and selectivity. This combinatorial protocol is well suited for fast and efficient screening and optimization of synthesis for uniform imprinted microspheres because 12 kinds of imprinting conditions can be performed simultaneously in this microfluidic device. POLYM. ENG. SCI., 2012. © 2012 Society of Plastics Engineers     

和厚朴酚分子印迹聚合物微球的制备及表征

采用单步溶胀聚合法制备了和厚朴酚分子印迹聚合物微球(MIPMs)。Scatchard分析表明分子印迹聚合物微球在识别和厚朴酚分子的过程中存在两类结合位点,其高亲和位点的解离常数为KD1=0.13 mmol/L,最大表观结合量Qmax=45.21μmol/g。静态吸附试验证明MIPMs对模板分子具有较强的特异吸附能力,以厚朴酚为竞争底物,其分离因子达1.85。