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1.
Savita Verma Deepak M. Maher Samadhan S. Nagane Bhausaheb V. Tawade Prakash P. Wadgaonkar 《Journal of polymer science. Part A, Polymer chemistry》2019,57(5):588-597
New aromatic (co)polyesters containing pendant propargyloxy groups were synthesized by phase transfer‐catalyzed interfacial polycondensation of 5‐(propargyloxy)isophthaloyl chloride (P‐IPC) and various compositions of P‐IPC and isophthaloyl chloride with bisphenol A. FTIR and NMR spectroscopic data, respectively, revealed successful incorporation of pendant propargyloxy groups into (co)polyesters and formation of (co)polyesters with desired compositions. (Co)polyesters exhibited good solubility in common organic solvents such as chloroform, dichloromethane, and tetrahydrofuran and could be cast into transparent, flexible, and tough films from chloroform solution. Inherent viscosities and number average molecular weights of (co)polyesters were in the range 0.77–1.33 dL/g and 43,600–118,000 g/mol, respectively, indicating the achievement of reasonably high‐molecular weights. The 10% weight loss temperatures of (co)polyesters were in the range 390–420 °C, demonstrating their good thermal stability. (Co)polyesters exhibited Tg in the range 146–170 °C and Tg values decreased with increase in mol % incorporation of P‐IPC. The study of non‐isothermal curing by DSC indicated thermal crosslinking of (co)polyesters via propargyloxy groups. The utility of pendant propargyloxy group was demonstrated by post‐modification of the selected copolyester with 1‐(4‐azidobutyl)pyrene, 9‐(azidomethyl)anthracene, and azido‐terminated poly(ethyleneglycol) monomethyl ether via copper(I)‐catalyzed Huisgen 1,3‐dipolar cycloaddition reaction. FTIR and 1H NMR spectra confirmed that click reaction was quantitative. © 2018 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2019 , 57, 588–597 相似文献
2.
Partially supported by the general research fund at the University of Kansas 相似文献
3.
Cyclic voltammetric studies of certain industrially potential iron chelate catalysts 总被引:1,自引:0,他引:1
For the analysis of infrared spectroscopic bands and complex patterns partial cross correlation functions of a sample spectrum
with reference spectra are calculated. The chosen ranges of the spectra are based on empirical knowledge of infrared spectrum
structure correlations. The normalised maxima of the partial cross correlation functions are interpreted as fuzzy truth values
and are combined by fuzzy logical operators. By application of that procedure larger common substructures will be derived
from the reference spectra than by a maximum common substructure search based on the complete spectra.
Received: 30 October 1996/Revised: 24 February 1997/Accepted: 26 February 1997 相似文献
4.
5.
In view of persisting discrepancy between experimental and theoretical results, specially in the weak radiative decays of∑ + andΞ 0, we analyse these decays within the framework of the QCD inspired quark-diquark model. On introducing a slightSU(6) breaking we obtainα(∑ +→p+γ)≈?0.9 which is in excellent agreement with experimental value. Other decays are also improved in this scheme. 相似文献
6.
Anupama Chaurasia Krishna K. Verma 《Fresenius' Journal of Analytical Chemistry》1995,351(2-3):335-337
2,4-Dinitrophenylhydrazine has been suggested as a new reagent for the flow-injection spectrophotometric determination of residual chlorine based on its oxidation to 2,4-dinitrophenyldiazonium ion. The measurement of the decrease in colour intensity under reversed flow-injection (reagent injection) conditions has been used for the determination of 0.1–10 mg/l Cl present as free or combined chlorine, and for its speciation. The limit of detection was 0.05 mg/l Cl. Copper (II), iron (III) and many other ions have been found not to vitiate the results. 相似文献
7.
Arylhydrazines are detected by oxidation with N-bromosuccinimide and coupling with resorcinol to form azo-dyes which are intensely coloured in alkaline media. Hydrazones and osazones are hydrolysed to form the arylhydrazines, which are then tested for 4-Nitro- and 2,4-dinitrophenylhydrazines are tested for by forming their hydrazone with salicylaldehyde and adding alkali to produce a violet colour. The hydroxylamine formed by the hydrolysis of oximes is oxidized by iodine monochloride in the presence of sulphanilic acid; coupling with 8-hydroxyquinoline forms a dye that is red in alkali. Intense colours are immediately produced when primary, secondary and tertiary aromatic amines are mixed with diacetoxyiodobenzene. All the tests are sensitive and appear to be specific. 相似文献
8.
An amperometric titration method is described for the determination of 1-5 mg of organic isothiocyanates, based on their quantitative reaction with n-butylamine in dimethylfonnamide to form N,N-disubstituted thioureas which are then titrated amperometrically in aqueous ammonia-ammonium nitrate buffer with silver nitrate (dropping mercury electrode at -0.56V). The end-point corresponds to a silver:thiourea ratio of 2:1, with precipitation of silver sulphide. The method is simple, accurate, widely applicable, and gives reproducible results. 相似文献
9.
Hydrated copper (II) perchlorate (in acetonitrile) has been used for the direct visual and potentiometric determination of ascorbic acid in acetic acid-acetonitrile media. Diphenylamine and diphenylbenzidine are suitable indicators. A bright platinum wire is used as indicator electrode and a modified calomel or an antimony electrode as reference electrode for the potentiometric titration. Ascorbic acid is oxidized to dehydroascorbic acid. The proposed method is simple, accurate and reliable. The reverse titration also works well. 相似文献
10.
Navjeet Kaur Yamini Verma Pooja Grewal Neha Ahlawat Pranshu Bhardwaj Nirmala Kumari Jangid 《合成通讯》2020,50(9):1286-1334
AbstractFew conversions cannot take place with ground-state reactions even with the help of a catalyst, therefore they are made to occur under photochemical conditions. The transfer of electrons took place even with the photochemical excitement of one molecule where redox reaction cannot occur at the ground state. The ground-state reactions resulted in the formation of side products. The substrates did not require any sort of chemical activation for C–N bond construction in the course of photochemical reactions. The source of energy; light has always been the interest of researchers in order to induce chemical reactions ever since the starting of scientific chemistry. The present review encloses the chemistry of photochemical transformations with a focus on their synthetic uses. The organic photochemical reactions prevent the polluting or harmful reagents thus, provides a possibility for sustainable procedures as well as green chemistry. This review article displays the formation of numerous of five-membered fused nitrogen-heterocyclic compounds. 相似文献