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61.
设计并合成了2-(2’-羟基-3’-甲氧基苯基)-5,6-二硝基苯并咪唑化合物(1),通过X射线单晶衍射研究了该化合物的固态结构.利用紫外-可见光谱技术研究了其对阴离子的识别,发现化合物1能够在DMSO中对AcO^-,H2PO4^-,OH^-的3种离子进行有效识别,同时溶液由原来的黄色变成红色,实现裸眼检测.  相似文献   
62.
Derivatives of 3-O-acetyl-18-H-glycyrrhetic acid were synthesized. Their structures and membrane activities were studied.  相似文献   
63.
Titration calorimetry was used to construct the solid-liquid equilibrium line in ternary systems containing the solute and an aqueous mixed solvent by measuring the heat of dissolution of the solid solute during successive additions of the liquid solvent. The plot of cumulated heats versus the mole ratio, nsolvent/nsolute, yields two (almost) linear increases of different slopes. These two lines represent successively the enthalpy of dissolution then the enthalpy of dilution of the medium; their intersection gives the solubility and the enthalpy of dissolution of the solute. Phase diagrams have been established over the whole concentration range for o-anisaldehyde, 1,3,5-trimethoxybenzene and vanillin, in water + methanol, +ethanol, or +n-propanol at 303, 313 and 318 K.  相似文献   
64.
Stability constants of the ternary complexes [CuAL] whereA = 5-Nitro-1,10-phenanthroline, bis(2-pyridyl) ketone (DPK) orbis(2-pyridyl)amine (DPA) andL is the dianion of catechol, tiron, protocatechic acid, pyrogallol, 1,8-dihydroxynaphthalene, catecholaldehyde, 2,3-dihydroxynaphthalene, dopamine or adrenaline have been determined by potentiometric titration in dioxane water (1:1 v/v) medium using a SCOGS computer programme. The observed trend of stability is explained on the basis of the nature of substitution over the ligands, chelate ring size and also the composition of mixed solvent in case of DPK. Structural changes in DPK have also been discussed as a function of pH, composition of medium and coordinating mode of the secondary ligand in the ternary complexes.  相似文献   
65.
When boiled in aromatic hydrocarbons, solutions of α-nitro-α-azinylcyanoacetic esters of the pyrimidine, pyrazine, ands-triazine series gave the corresponding α-hydroxy derivatives of α-azinylcyanoacetic esters in high yields. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 7, pp. 1407–1409, July, 1997.  相似文献   
66.
Chu TY  Chang CH  Liao YC  Chen YC 《Talanta》2001,54(6):1010-1171
A rapid method for the derivatization of phenolic antioxidants using microwave irradiation has been developed. Six antioxidatively active phenolic components of wines and fruits, namely gallic acid, gentisic acid, vanillic acid, caffeic acid, ferulic acid and p-coumaric acid were used in the model study. The solution of phenolic acids was evaporated to dryness on a rotary evaporator followed by further drying under microwave irradiation (600 W, 30 s). The resultant residue was dissolved in pyridene and treated with bis(trimethylsilyl)acetamide while irradiated by microwave using high power for 30 s. Controlled reaction was carried out employing bis(trimethylsilyl)trifluoroacetamide under conventional heating for 30 min. The trimethylsilyl derivatives were identified and quantified on a gas chromatography/mass selective detector. The mass spectral fragmentation patterns of the derivatives obtained by microwave irradiation were identical to those prepared by heating. The yields of microwave-assisted silylation were comparable to those from conventional heating. The rsd were less than 8% for six replicates. The linearity in wine matrix was nearly perfect. This method is a useful protocol to examine the phenolic constituents in wines and agricultural products.  相似文献   
67.
Summary. A facile synthesis of quinoxaline derivatives catalyzed by KHSO4 in very high yields at room temperature is reported.  相似文献   
68.
纤维素衍生物手性固定相研究进展   总被引:1,自引:0,他引:1  
何永祝  庞浩  廖兵 《化学进展》2006,18(7):957-965
本文从用作手性固定相的纤维素衍生物种类、纤维素衍生物手性固定相制备方法及其在高效液相色谱中的应用三个方面介绍了国内外近年来的研究进展,并展望了该领域今后的研究方向。  相似文献   
69.
本文从用作手性固定相的纤维素衍生物种类、纤维素衍生物手性固定相制备方法及其在高效液相色谱中的应用三个方面介绍了国内外近年来的研究进展,并展望了该领域今后的研究方向。  相似文献   
70.
A method for preparing (trichloromethyl)organosilanes by the catalytic decarboxylation of the corresponding trichloroacetoxysilanes RMe2SiOC(O)CCl3 (R = Me, ClCH2, Ph, Me3Si, and H) has been developed. The method involves heating the starting compounds without a solvent in the presence of a catalyst (quaternary ammonium salts or potassium salts with the addition of crown ethers). Tertiary amines (Et3N, Bu3N) catalyze this reaction only when heating is carried out in donor aprotic solvents (THF, acetonitrile) in the presence of oxygen. Thermal decomposition of (trichloroacetoxy)organosilanes, in contrast to catalytic decarboxylation, begins at a higher temperature and yields a mixture of products.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 1, pp. 150–153, January, 1995.  相似文献   
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