Aqueous Solutions Of Formamide Research Articles

Freezing temperatures of aqueous solutions containing formamide, acetamide, propionamide and N,N-dimethylformamide. Free energy of interaction between the CONH and CH2 groups in dilute aqueous solutions

The freezing temperatures of dilute aqueous solutions of formamide, acetamide, propionamide and dimethylformamide have been determined. The data have been used, in association with appropriate enthalpy and heat capacity data, to calculate the pairwise free energy of self interaction coefficients at 298.15 K.The results for the unsubstituted amides are predicted with reasonable accuracy using the group additivity approach developed previously. In contrast to the results for the enthalpies of interaction, the free energies of interaction of the disubstituted amides are not accurately predicted.

The influence of temperature on the diffusion coefficient of europium in aqueous formamide solutions

The influence of temperature on the diffusion coefficient of Eu(III) in 1.0 M NaClO 4 aqueous formamide solutions is studied by chronopotentiometry. It is shown that the solution viscosity is the main reason for the changes of the diffusion coefficient when temperature and formamide concentration are varied. The values of solvodynamic radii and activation energy for diffusion are presented

Renaturation kinetics and thermal stability of DNA in aqueous solutions of formamide and urea.

This paper reports the results of a systematic study of the effects of formamide and urea on the thermal stability and renaturation kinetics of DNA. Increasing concentrations of urea in the range 0 to 8 molar lower the Tm by 2.25 degrees C per molar, and decreases the renaturation rate by approximately 8 percent per molar. Increasing concentrations of formamide in the range from 0 to 50 percent lowers the Tm by 0.60 degrees C per percent formamide for sodium chloride concentrations ranging from 0.035M to 0.88M. At higher salt concentrations the dependence of Tm on percent formamide was found to be slightly greater. Increasing formamide concentration decreases the renaturation rate linearly by 1.1% per percent formamide such that the optimal rate in 50% formamide is 0.45 the optimal rate in an identical solution with no formamide. The effects of urea and formamide on the renaturation rates of DNA are explained by consideration of the viscosities of the solutions at the renaturation temperatures.

Renaturation of bacteriophage lambda DNA. Determination of the optimal renaturation conditions using a single-strand-specific DNase and alkaline-sucrose-gradient assay system.

Reannealed hybrid molecules of wild-type bacteriophage lambda DNA were prepared in aqueous solutions of formamide at a variety of NaCl concentrations at both room temperature ( 22 degrees C) and 37 degrees C. Treatment of the hybrid DNA molecules with the single-strand-specific nuclease S1 from Aspergillus oryzae followed by alkaline sucrose gradient sedimentation was used to monitor the extent and fidelity of hybridization. The optimal renaturation conditions at room temperature were found to be: 50% formamide, 35-55 mM NaCl and 10 mM Tris-HCl (pH 8.5) at 20-25 mug DNA/ml. Optimal conditions at 37 degrees C were: 32% formamide, 35-55 mM NaCl and 10 mM Tris-HCl (pH 8.5) at 20-25 mug DNA/ml. Under these conditions approximately 85-90% of the input single-stranded DNA (molecular weight 1.5 X 10(7)) was rendered S1-nuclease-resistant within 8 h at room temperature and 5 h at 37 degrees C. Neither Mg2+ nor spermidine appeared to have an effect on either the extent or fidelity of duplex formation. Experiments performed with excess enzyme and with lambda/lambda imm 434 heteroduplex hybrids suggested that the hybrid that the hybrid DNA molecules formed under optimal conditions contained no, or only short (less than 1%), mismatched regions.

Electrochemistry of Europium in Aqueous and Aqueous Formamide Solutions

Abstract The electrochemical behavior of the system Eu(III)/Eu(II) in aqueous formamide solutions was studied by current reversal chronopotentiometry at a mercury pool electrode, in 1 M NaClO4 The results indicate that double layer effects must be considered rather that ion solvation effects when explaining the influence of formamide on the Eu(III)/Eu(II) electrode reaction.

Studies on Ovalbumin. III. Denaturation of Ovalbumin and S-Ovalbumin

Ovalbumin and S-ovalbwnin have been compared by measuring their viscosity and optical rotatory dispersion in aqueous formamide solutions at pH 7 and in urea solutions at pH 3�5; also by measuring the optical rotatory dispersion of heated solutions at different salt concentrations, and by a study of ultraviolet differlilnce spectra in alkylamine hydrochloride solutions. The different aggregation behaviour of the two proteins after denaturation suggests a difference in covalent bond structure.

Aggregation of chlorophylls in aqueous-formamide solutions

Chlorophylls a and b undergo aggregation in aqueous-formamide solutions. The chlorophyll a aggregate exhibits absorption bands at 690 mμ and 463 mμ, while that of chlorophyll b are located at 669 mμ and 500 mμ. Studies with pheophytin show that the presence of magnesium is not necessary for aggregation. Less aggregation is observed in the presence of imidazole and urea. The photosensitizing activity and the photoautooxidation of the chlorophyll a aggregate are reported. Chlorophylls a and b are shown to form coaggregates in formamide solutions. Suspensions of formamide-treated chloroplast in buffer undergo spectral shifts similar to those found with hot methanol treatment.

Heat of Solution, Heat Capacity, and Density of Aqueous Formamide Solutions at 25° C.

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTHeat of Solution, Heat Capacity, and Density of Aqueous Formamide Solutions at 25° C.E. P. Egan Jr. and B. B. LuffCite this: J. Chem. Eng. Data 1966, 11, 2, 194–196Publication Date (Print):April 1, 1966Publication History Published online1 May 2002Published inissue 1 April 1966https://doi.org/10.1021/je60029a021RIGHTS & PERMISSIONSArticle Views203Altmetric-Citations28LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (278 KB) Get e-Alerts Get e-Alerts