微波干法催化醛酮与胺的缩合反应

利用微波辐射和固体中性Al2 O3 载体催化醛酮与胺的缩合反应的方法合成了十六种亚胺 ,研究了微波功率、作用时间、产物提取方式等因素对反应的影响 ;与无微波作用的一般合成方法相比 ,该法明显地提高反应速度及产率 ;文中用低极性熔点递变物质灌装毛细管的方法观测微波作用下反应温度 ,探讨微波作用化学反应的机理 ,其机理除与微波加热作用有关外还与分子间氢键及分子的缔合性有关。     

微波辐射用于聚酰亚胺的研究进展

聚酰亚胺因具有优良的综合性能而得到广泛的研究.微波辐射在高分子化学研究领域中的应用越来越广泛,效果也十分明显.与常规加热方式相比,微波辐射具有内部加热、缩短反应时间、提高反应产率、节省能耗、无温度梯度、制得产物性能好等优点.近年来,微波辐射用于聚酰亚胺的研究越来越多.因此本文对微波辐射在聚酰亚胺的合成、三阶非线性光学、聚酰亚胺复合材料以及稀土-聚酰亚胺配合物等方面的应用进行了综述.     

微波促进的Dimroth重排反应合成吡啶并[2,3-d]嘧啶-4-胺衍生物（英文）

研究了N-(3,5-二氯苯基)吡啶并[2,3-d]嘧啶-4-胺的合成新方法.在微波辐射条件下,以2-氨基-3-氰基吡啶为原料,依次通过缩合、环化和Dimroth重排两步反应,得到目标产物N-(3,5-二氯苯基)吡啶并[2,3-d]嘧啶-4-胺,总收率90%.并应用该方法,合成了20个吡啶并[2,3-d]嘧啶-4-胺类化合物.同时,比较了微波辐射和传统油浴加热条件下的反应结果.结果表明,微波辐射条件下,反应时间短,产率高.此方法有望成为一种高效、温和、对环境友好的合成吡啶并[2,3-d]嘧啶-4-胺的方法.     

微波辐射下2-取代苯并咪唑衍生物库的平行合成

以邻苯二胺及相应羧酸为原料,于多聚磷酸存在下,由微波辐射平行合成了一个小型2-取代苯并咪唑衍生物库,反应时间由常规加热的几小时到几天缩短为20min,且产率较高。经元素分析和1H NMR确证了产物结构。     

微波辐射下三甲醇丙烷、季戊四醇与羧酸合成润滑油类羧酸酯

用三甲醇丙烷、季戊四醇分别与碳五至碳九的直链一元羧酸在微波辐射加热条件下合成润滑油类羧酸酯,并与常规合成进行了对照.结果表明:在微波辐射下反应时间大大缩短,合成速率提高到10～15倍,该法操作简单,产物用1H NMR,13C NMR和IR确定了结构.     

纳米结构羟基磷灰石的微波固相合成新方法

本文报道了一种简单的室温下微波辅助合成羟基磷灰石(HAP)的新方法。与常规方法相比，该方法具有反应条件温和、反应时间极短的优点。合成中，以Ca(NO₃)₂·4H₂O和Na₃PO₄·12H₂O为原料，经过研磨和微波加热得到了HAP纳米粒子和纳米棒。用XRD、FTIR，BET和SEM等对产物进行了表征。在反应过程中，微波辐射作为一种加热处理手段对HAP的形成起到非常重要作用。同时     

微波法煅烧高岭土及合成洗涤助剂4A沸石

本文用微波法煅烧高岭土并合成4A沸石.与传统高温热处理法相比,微波法煅烧的高岭土其活化深度好,增白程度高,粒度细,能耗大为降低,显示了明显的优越性.本文还采用煅烧后的活性高岭土为原料,在微波辐射下进行4A沸石的合成,并用XRD、DTA、SEM、白度计、钙离子交换度等进行表征.与传统水热处理法相比,微波法所得样品在结晶度、白度和钙离子交换能力方面均显优势,且大大地加快了沸石晶化反应速率.经动力学处理,发现微波法合成4A沸石的晶核形成及晶体成长的表观活化能均有所下降,说明微波辐射能促进新相的形成,加快整个晶化反应速率.     

微波诱导快速合成纳米NaY分子筛

报导了一种在常压回流微波加热条件下,可使合成的NaY分子筛晶粒尺寸减小至100 nm以下的方法.添加柠檬酸的晶化速率接近添加稀土离子的晶化速率,合成60 min后两者得到的NaY分子筛的晶粒度和硅铝比接近,约为40 nm和5.2,晶粒度小且硅铝比高于在相同条件下没有添加合成得到的NaY分子筛.微波合成的NaY分子筛的晶粒度明显小于常规相同配比所得样品的晶粒度且晶化时间明显缩短,充分证明了微波加热快速均匀且能够得到较小晶粒度的特点.     

杀结核菌素的全合成研究

杀结核菌素是一个吡咯[2,3-d]嘧啶核苷天然产物,具有显著的抗血吸虫感染、抗菌和抗肿瘤活性.报道了以微波促进的Vorbrüggen糖基化反应为关键步骤,以6-氯-7-溴-吡咯[2,3-d]嘧啶和1-O-乙酰基-2,3,5-O-三苯甲酰基-β-D-呋喃核糖为原料,经过3步反应以74%的总收率完成了杀结核菌素的全合成.同时研究了以全氟丁基磺酸钾、三甲基氯硅烷和硅基化试剂[六甲基二硅胺烷或者N,O-双(三甲基硅基)乙酰胺]在微波加热下一锅法合成7-去氮嘌呤核苷的方法.     

相转移催化与微波辐射合成三(2-氰乙基)胺

将微波辐射与相转移催化技术相结合,在加压密闭容器中,以氨水和丙烯腈合成了配位中间体三(2-氰乙基)胺,产率为61.2%,合成时间比传统方法缩短了8倍;在微波辐射下,产率为67.2%,合成时间缩短约90倍.对产物进行了元素分析,IR,¹H-NMR,ES-MS,及TG-DTA表征.     

Neutral diterpenoids of oleoresins of five species of conifers of Transcarpathia

The compositions of the neutral diterpenoids of the oleoresins of five species of conifers growing in the Transcarpathia have been studied. It has been found that the oleoresins ofAbies alba M.,Larix decidua M., andPicea excelsa L. contain more than 50% of neutral diterpenoids. The group and qualitative compositions of the oxygen-containing diterpenoids have been determined. In the oleoresins ofAbies alba,Picea excelsa, andPicea abies tertiary alcohols — cis-abienol and isocembrol — predominate, while inLarix decidua the main component is the hydroxy ester larixyl acetate. Primary alcohols related to the resin acids have been found in all the oleoresins investigated. Features of the distribution of diterpenoids according to the species of conifers have been revealed. The results obtained are necessary for the chemotaxonomy of conifers of the family Pinceae.Novosibirsk Institute of Organic Chemistry, Siberian Branch, Academy of Sciences of the USSR. Translated from Khimiya Prirodynkh Soedinenii, No. 6, pp. 812–816, November–December, 1988.     

利用手持技术改进测定乙醇分子结构实验

利用压强传感器代替排水集气法,改进测定乙醇分子结构实验的仪器装置,并探索最佳反应条件。另外,设计两个空白实验,结合压强变化曲线对实验误差进行相关讨论。     

光谱仪测试范围的扩展

由于石化行业的生产需要，其材质的使用具有多样性和广泛性，经常会出现顾客委托的测试样品的一个或几个元素跨越光谱仪现有测试程序测量范围的情况。本法通过对光谱仪测试原理的认识，根据光谱仪的测试能力及标样的采集，实现了一个或几个元素测量范围的扩展，并对其测量的影响因素进行了研究。     

Effect of the Method of Modification of Zeolite X on Selectivity of Catalytic Methylation of Toluene

Theoretical and Experimental Chemistry - The effect of the method of modification of catalysts based on zeolite X by cesium and magnesium cations (ion exchange and impregnation) on the selectivity...     

Influence of viscosity of medium on processes of oxygen quenching of excited states of mesoporphyrin

The oxygen quenching rate constants for singlet and triplet excited states of the dimethyl ester of mesoporphyrin IX increase with decreasing viscosity of the medium and reach a maximum at a viscosity of approximately 0.4 mPa·sec, after which the rate constants begin to decrease. The drop in rate constant with increasing fluidity of the medium may be related to a nonequilibrium character of the elementary act in the interaction of the reactants in the solvent cage. In viscous media such as isopropyl alcohol, isobutyl alcohol, and isoamyl alcohol, the reaction radius is greater than the sum of the radii of the reacting particles. The long-range character of these processes is due to the relatively weak dependence of the quenching probability on distance.Translated from Teoreticheskaya i Éksperimental'naya Khimiya, Vol. 25, No. 2, pp. 161–167, March–April, 1989.     

Dichroism of absorption and polarization of phosphorescence of molecules of the closed form of nitrobenzospirothiopyran

The spectral-polarization characteristics of absorption and phosphorescence of molecules of the initial form of nitro-substituted indolinospirobenzothiopyran were studied in oriented polyethylene films and in solutions with different polarity. An oscillator model of the electron transitions responsible for the formation of absorption and luminescence spectra was suggested. It was established that the principal differences in the spectral and photophysical properties of the compound studied and its oxygen-containing analog are associated with the fact that the electronegativity of the S atom is lower than that of the O atom. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 6, pp. 1143–1146, June, 1997.     

Synthesis of tetrabenzoporphins of the basis of isoindoline

Chemistry of Heterocyclic Compounds -