Highly Enantioselective Biginelli Reaction Promoted by Chiral Bifunctional Primary Amine‐Thiourea Catalysts: Asymmetric Synthesis of Dihydropyrimidines

The diastereospecific formation of dihydropyrimidines (DHPMs) has been achieved in moderate to high yields with up to 99% ee by a Biginelli reaction. The reaction was performed by using a combined catalyst consisting of a chiral bifunctional primary amine‐thiourea 9f and a Brønsted acid with tert‐butylammonium trifluoroacetate (t‐BuNH₂⋅TFA) as additive in dichloromethane at room temperature. The possible mechanism for the reaction has been proposed to explain the origin of the activation and the asymmetric induction.     

对苯二甲酰基硫脲衍生物的合成及其生物活性

合成了9个对苯二甲酰基硫脲化合物,采用1HNMR、IR、MS和元素分析对其结构进行了表征,并首次对其植物生长调节活性进行了测试.初步的生理活性研究表明,部分目标化合物,如N,N′-邻硝基苯基对苯二甲酰基硫脲等具有非常高的植物生长调节活性.     

含吡啶环的双酰基硫脲衍生物的合成与生物活性

采用相转移催化法合成了6个含吡啶的双硫脲类新的化合物,其结构经1H NMR、IR、MS和元素分析表征。生物活性测试结果表明所设计化合物具有一定的植物生长调节活性。     

曼尼希碱及其复配缓蚀剂性能的研究

通过使用CMB-4510A缓蚀剂快速评定仪研究了曼尼希碱、硫脲、钨酸钠三种缓蚀剂单独使用及以曼尼希碱为主的二元复配体系对10#碳钢在石油模拟腐蚀液中的缓蚀效果。针对高酸高氯的原油,添加缓蚀剂是一种最有效的防止碳钢腐蚀的方法。实验结果表明：温度为50。C,pH值为6．0时,单独使用曼尼希碱、硫脲和钨酸钠对10#碳钢都有一定的缓蚀效果,其中曼尼希碱和钨酸钠的缓蚀性能优于硫脲;以曼尼希碱为主的缓蚀剂分别与硫脲和钨酸钠进行二元复配,其缓蚀效果均好于单独使用时的缓蚀效果。     

某硫铁矿烧渣的硫脲法浸金银研究

针对某硫铁矿烧渣进行了硫脲法搅拌浸金、银研究,考察了磨矿细度、硫脲浓度、pH值、液固比、搅拌时间、矿浆温度、浸出剂种类对金、银浸出率的影响。结果表明,适宜的搅拌浸出条件为: 磨矿细度-0.074 mm粒级占89%、硫脲浓度15 g/L、pH=2.5、液固比3、搅拌时间7.5 h、矿浆温度50 ℃,此条件下金、银浸出率分别达到84.8%、72.1%。     

硫脲插层高岭土对PP阻燃和力学性能的影响

采用三步插层取代法制备了硫脲插层高岭土插层复合物(TU-Kaol),通过熔融共混法将TU-Kaol添加到聚丙烯(PP)中,通过锥形量热和万能试验机测试PP/TU-Kaol复合材料的阻燃性能和力学性能。结果表明,当TU-Kaol含量为1.5 %（质量分数,下同）时,PP/TU-Kaol 复合材料的最大热释放速率从纯PP的1 474 kW/m2下降至1 100 kW/m2;拉伸强度从纯PP的35.3 MPa提高至39.8 MPa,表明TU?Kaol对PP的阻燃和力学性能具有显著效果。     

酸性硫脲浸金液中金的富集研究

研究了D072大孔强酸性阳离子交换树脂从硫脲[Tu=CS(NH2)2]浸金液中吸附Au(Tu)2^ 的性能和机理。结果表明：在pH=2.0时,树脂对Au(Tu)2^ 有优良的吸附性能,1gD072大孔强酸性阳离子交换树脂金的交换容量为78．95mg,吸附的硫脲金可用乙醇-硫酸水溶液洗脱,洗脱率可达96．5％。D072树脂对Au(Tu)2^ 的吸附符合Langmuir吸附模型。     

化探样品中的痕量金测定方法的改进

以1+1王水、加入一定量FeCl3溶液,对化探样品进行加热分解1h.经泡沫塑料吸附后,于90℃以上1％硫脲溶液中解吸30 min,然后采用石墨炉原子吸收光谱仪测定其中的金含量.其中对仪器分析条件进行了优化.金的质量分数在0.10～ 20.0 ng/g范围内与吸光度呈良好的线性,方法标准曲线线性相关系数为0.9993,检...     

Solvent extraction of silver(I) from nitrate media using thiourea derivatives

Liquid–liquid extraction of Ag(I) from nitrate solutions using N‐(N′,N′‐diethyl thiocarbamoyl)‐N″‐phenylbenzamidine (TCBA) and 1‐6,‐diethylcarbamoyl imino‐1,6‐diphenyl‐2,5 dithiahexane (TCTH) dissolved in cumene has been studied. The extraction of Ag(I) from 1 mol dm⁻³ NO₃⁻ solutions by TCTH and TCBA was investigated as a function of several variables: equilibration time, organic phase diluent, pH of aqueous phase, Ag(I) and NO₃⁻ concentration in aqueous phase as well as TCBA and TCTH concentrations. Experimental equilibrium data were analysed numerically using the programs LETAGROP‐DISTR and LETAPL and the results showed that Ag(I) extraction could be explained assuming the formation of AgL and AgNO₃HL with TCBA (HL) and AgNO₃S with TCTH (S). The metal extraction was not influenced significantly by the structures of the thiourea derivatives used as extractants. The back extraction of Ag(I) from loaded organic phase was performed using different strippants and 0.5 mol dm⁻³ NaSCN was found to be efficient for this purpose. © 2000 Society of Chemical Industry     

SC(NH2)2-H2O2-Cu2+-OH-封闭体系非线性动力学研究

利用微量量热仪测定体系热功率随时间的改变。对于SC(NH2)2-H2O2-Cu2 -OH-封闭体系,测定了不同浓度,不同温度下,体系的单峰振荡行为,得到了不同温度,不同浓度下的振荡周期,并由此计算出振荡反应的表观活化能和反应级数。并得到下列关系:1t∝c-0.3355