Condensation–cyclization reaction for one-pot synthesis of 1,3-thiazolidin-4-one derivatives by poly(p-phenylenediamine) grafted on LDHs as a catalyst with green tool

The three-component reaction between amine, carbonyl compound and thioglycolic acid is now considered as a major strategy for synthesis of 1,3-thiazolidin-4-ones, which consists of the following steps: (i) condensation of aldehyde and amine which results the formation of an imine; (ii) the reaction between thioglycolic acid and the imine which is followed by an intramolecular cyclization reaction, which leads to the formation of the final product. In this way, if no suitable catalyst is employed, the completion of the reaction will not be achieved. Hence, it is of great importance to select an appropriate catalyst so that these compounds can be successfully synthesized. Herein, we employed LDHs@PpPDA as a versatile catalyst for the fabrication of novel derivatives of 1,3-thiazolidin-4-one.     

Low temperature cleanup combined with magnetic nanoparticle extraction to determine pyrethroids residue in vegetables oils

To quantify trace pesticide residue in vegetable oil rapidly, low temperature cleanup combined with magnetic nanoparticle based solid phase extraction was developed to determine eight pyrethroids in vegetable oils, including tetramethrin, fenpropathrin, cypermethrin, decamethrin, fenvalerate, acrinathrin, permethrin and bifenthrin. Polystyrene coated magnetic nanoparticles were synthesised by a modified chemical coprecipitation combined with emulsion polymerisation method. The nanoparticles were afterwards characterised by Fourier transform-infrared spectroscopy, X-ray diffraction, transmission electron microscopy as well as vibrating sample magnetometer, and successfully employed as adsorbents for the magnetic solid phase extraction of pyrethroids which were cleaned up using low temperature approach in advance. Critical impact factors on the efficiency of the extraction method such as the mass of adsorbents used, volume and type of eluent solvent, extraction time as well as elution time were optimised subsequently. Regression analysis of the calibration curves of the eight pyrethroids yielded satisfactory correlation coefficients within the range of 0.980–0.998. Limit of detection and limit of quantification were calculated to be between 0.0290-0.0658 and 0.0890–0.1994 ng g⁻¹, respectively. Intra-day and inter-day reproducibility at different concentration levels also produced satisfactory recovery rates of 83.18–112.79% with relative standard deviations not exceeding 10.84% and 12.01%, respectively, suggesting desirable stability of the proposed method.     

PDZ颗粒度对合成锆钒蓝陶瓷颜料的影响

试验研究了ＰＤＺ原料颗粒度对ＰＤＺ合成锆钒蓝陶瓷颜料呈色性能的影响，对ＰＤＺ颗粒度减小后合成的锆钒蓝星色变差的原因进行了理论分析与讨论。     

磁性纳米镁铝水滑石的合成研究

利用共沉淀法合成出磁性纳米镁铝水滑石，并借助于XRD，TEM，振动样品磁强计等手段研究了铁（Ⅱ）／镁摩尔比对水滑石结构和磁学性能的影响。这为层状材料与磁性基质进行复合制备新型功能材料提供了实验依据。     

1,6-己二醛合成工艺研究

根据环己烯分子结构特点及相关反应的基础理论,提出在甲酸作为载氧剂的条件下,以过氧化氢氧化环己烯制备反式-1,2-环己二醇的工艺路线;并使用高碘酸钠/硅胶体系氧化反式-1,2-环己二醇制备1,6-己二醛.通过单因素实验法对在合成过程中的物料配比、反应温度、反应时间、重结晶方法等诸多因素对反应的影响进行考察.以气相色谱对产品纯度进行分析,得出反式-1,2-环己二醇及1,6-己二醛的纯度分别为98.93%和99.97%,并利用GC、红外光谱、核磁共振等分析方法对其产品化学结构进行确认.     

VHDL编码中面积优化探讨

VHDL包含的语句非常丰富，不同的描述可以实现同样功能的电路，但可能在对资源的利用率上存在差异。根据应用MaxplusⅡ软件进行VHDL语言代码编写的经验，结合相应实例，阐述有关VHDL编码方面的面积优化问题。     

Study on novel poly (vinyl pyrrolidone) doped MWCNTs/polyrhodanine nanocomposites: Synthesis,characterization, and thermal performance

In this paper, poly (vinyl pyrrolidone) (PVP) doped multiwall carbon nanotubes (MWCNTs/polyrhodanine), were synthesized through one-step chemical oxidative polymerization of rhodanine monomers on the surface-modified carbon nanotubes. Characterization of MWCNTs/polyrhodanine was conducted by using scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier transforms infrared spectroscopy (FT-IR), X-ray diffraction (XRD), and EDX spectrum analyses in which the results confirmed the successful formation of MWCNTs/polyrhodanine. In addition, to investigate the thermal properties of samples, thermogravimetric analysis (TGA) was employed, and results exhibited significant improvement in the nanocomposite thermal stability due to the addition of MWCNTs with reinforcement effect in polymer matrix.     

黄药合成工艺的生产实践

本文介绍了永平铜矿强力公司黄药合成的工艺概况 ,并论述了在生产实践中对提高产品质量所采取的主要措施     

新型聚丙烯酸类浆料单体组分对浆料生物降解性能研究及浆料合成

本文主要以浆料生物降解性能作为评价指标.从单体配比设计着手,以标准邻苯二甲酸氢钾标准溶液的COD（Chemical Oxygen Demand）值和葡萄糖-谷氨酸钠盐标准溶液的BOD（Biochemi-cal Oxygen Demend）值为参考,测试了7种不同配比的浆料的CODCr/BOD5值.并由实验所得最佳单体配比,合成新型聚丙烯酸浆料.在实验所得丙烯酸和丙烯酰胺的最佳单体配比下合成的浆料生物降解性能较好,可生化.     

防晒剂丁基甲氧基二苯甲酰甲烷（巴松1789）的合成工艺研究

以大茴香醚和甲苯为原料 ,经烷基化 ,氧化 ,酯化 ,酰基化和缩合五步反应合成了丁基甲氧基二苯甲酰甲烷 (巴松1789)防晒剂 ,傅 -克烷基化反应温度控制在 5 - 8℃转化率最高 ,为 77% ;氧化反应中加入叔丁基溴化铵相转移剂 ,反应时间可缩短至 4h ,酯化反应合成对甲氧基苯乙酮的最佳条件为 :n(乙酸酐 ) :n(苯甲醚 ) =1.9:1;n(无水氯化锌 ) :n(苯甲醚 ) =3:4 ;反应时间为 3h ;总收率为 5 2 .5 %。