Interactions in aqueous nonelectrolyte systems. Gibbs energy of interaction of the ether group with the hydroxyl group and the amide group

1985 ◽  
Vol 14 (11) ◽  
pp. 781-794 ◽  
Author(s):  
Sushil K. Suri ◽  
Jan J. Spitzer ◽  
Robert H. Wood ◽  
Edwin G. Abel ◽  
Peter T. Thompson
Keyword(s):  
Gibbs Energy ◽  
Amide Group ◽  
Hydroxyl Group ◽  
Ether Group ◽  
Energy Of Interaction

scholarly journals Correlation between Functional Group and Formation of Nanoparticles in PEBAX/Ag Salt/Al Salt Complexes for Olefin Separation

Polymers ◽  
2020 ◽  
Vol 12 (3) ◽  
pp. 667
Author(s):  
So Young Kim ◽  
Younghyun Cho ◽  
Sang Wook Kang
Keyword(s):  
Fourier Transform ◽  
Metal Ions ◽  
Polymer Matrix ◽  
Functional Group ◽  
Metal Salt ◽  
Amide Group ◽  
Separation Performance ◽  
Ether Group ◽  
Long Time ◽  
Ft Ir

poly ether-block-amide (PEBAX)-2533/metal salt/Al salt membranes were prepared for mixed olefin/paraffin separation. PEBAX-2533 with 80% ether group and 20% amide group was suggested as the polymer matrix for comparison of separation performance according to the functional group ratio in copolymer PEBAX. In addition, Al salts were used to stabilize metal ions for a long time as additives. High permeance was expected with the proportion of high ether groups, since these functional groups provided relatively permeable regions. As a result, the PEBAX-2533 composite membrane showed a selectivity of 5 (propylene/propane) with 10 GPU. However, the permeance of membrane was not unexpectedly improved and the selectivity was reduced. The result was analyzed by using SEM, RAMAN and thermogravimetric analysis (TGA), including Fourier transform infrared (FTIR). The reduction in separation performance was determined by using FT-IR. Based on these results, in order to stabilize the metal ions interacting with the polymer through Al(NO3)3, it was concluded that a specific ratio of the amide group was needed in PEBAX as a polymer matrix.

Gas-chromatographic method for acetaminophen (N-acetyl-p-aminophenol) based on sequential alkylation.

1976 ◽  
Vol 22 (6) ◽  
pp. 879-883 ◽  
Author(s):  
W A Dechtiaruk ◽  
G F Johnson ◽  
H M Solomon
Keyword(s):  
Serum Concentration ◽  
Chromatographic Method ◽  
Parent Compound ◽  
Internal Standard ◽  
Amide Group ◽  
Phenolic Hydroxyl ◽  
Hydroxyl Group ◽  
Methyl Derivative ◽  
Chromatographic Procedure ◽  
Gas Chromatographic Method

Abstract A gas-chromatographic procedure for acetaminophen is described in which the drug is chromatographed as the O-heptyl-N-methyl derivative. This derivative is prepared by a sequential alkylation procedure in which the phenolic hydroxyl group of the parent compound is alkylated off-column with heptyl iodide and the amide group is derivatized on-column by reaction with trimethylanilinium hydroxide. The internal standard, N-propionyl-p-aminophenol, is subjected to the same derivatization procedure. This gas-chromatographic procedure correlates well with conventional colorimetric and spectrophotometric procedures for acetaminophen and is more sensitive. Within-run precision (CV) was 2.0% at a serum concentration of 10.0 mg/liter (n = 10) and between-run precision was 4.0% over a period of eight months. This method is particularly applicable to studies of the pharmacokinetics of acetaminophen.

scholarly journals Tautomerism as primary signalling mechanism in metal sensing: the case of amide group

2019 ◽  
Author(s):  
Vera V Deneva ◽  
Georgi Dobrikov ◽  
Aurelien Crochet ◽  
Daniela Nedeltcheva ◽  
Katharina M Fromm ◽  
...  
Keyword(s):  
Earth Metal ◽  
Intramolecular Hydrogen Bonding ◽  
Amide Group ◽  
Hydroxyl Group ◽  
Sensing Systems ◽  
Alkaline Earth Metal Ions ◽  
Visible Spectra ◽  
Intramolecular Hydrogen ◽  
Metal Sensing ◽  
Signaling Process

The concept for sensing systems using the tautomerism as elementary signaling process has been further developed by synthesizing a ligand containing 4-(phenyldiazenyl)naphthalene-1-ol as a tautomeric block and an amide group as metal capturing antenna. Although it has been expected, that the intramolecular hydrogen bonding (between the tautomeric hydroxyl group and the nitrogen atom from the amide group), could stabilize the pure enol form in some solvents, the keto tautomer is also observed. This is a result from formation of intramolecular associates in some solvents. Strong bathochromic and hyperchromic effects on the visible spectra accompany the complex 1:1 formation with some alkaline earth metal ions.

Spectroscopic Determination of Dissociation Constants of Some 4-nitrobenzaldehyde-4-substitutedphenyl-1-carbonylhydrazones in Sodium Hydroxide Media

2020 ◽  
Vol 16 ◽  
Author(s):  
Mirjana S. Jankulovska ◽  
Ilinka Spirevska ◽  
Vesna Dimova ◽  
Milena Jankulovska
Keyword(s):  
Sodium Hydroxide ◽  
Dissociation Constants ◽  
Wide Spectrum ◽  
Amide Group ◽  
Hydroxyl Group ◽  
Semiempirical Methods ◽  
Dissociation Process ◽  
Vis Spectroscopy ◽  
The Media

Purpose: Hydrazones are a class of azomethines with a wide spectrum of pharmacological properties which are influenced by pH of the media. The purpose of this study was investigation of acid-base properties of five 4-nitrobenzaldehyde-4-substitutedphenyl1-carbonylhydrazones in sodium hydroxide media (14>pH>7). Method: The dissociation process was followed by UV-Vis spectroscopy, in the ethanol-water (V/V, 1:1) solutions, at room temperature. Semiempirical methods AM1 and PM3 were applied for determination of the deprotonation enthalpies. Results: The changes in the UV-Vis spectra, as well as the deprotonation enthalpies suggested that dissociation process for four investigated hydrazones with amide group took place in one step. The exception with two dissociation steps was hydrazone with amide and hydroxyl group. The pH region of dissociation was from pH 10.8 to pH 11.6 for the first step and between pH 11.7 and pH 12.1 for the second step of dissociation. The influence of the ethanol on the UV-Vis spectra was eliminated by the method of Characteristic Vector Analyses (CVA). The stoichiometric dissociation constants were determined numerically (pKHA = n·pH + logI) and graphically (intercept of the dependence of logI on pH) from the absorbance data using experimental and reconstructed UV-Vis spectra, at three different ionic strengths. Thermodynamic dissociation constants were estimated graphically as an intercept of dependence of dissociation constant on square root of the ionic strength. Conclusion: The obtained results demonstrated that the influence of the substituents on pKHA values was not significant, except for hydrazone with amide and hydroxyl group. Namely, the dissociation of amide group of this hydrazone was retarded due to the influence of phenolic group.

Conversion of the hydroxyl group in 1-hexyl alcohol to an amide group in supercritical water without catalyst

2003 ◽  
Vol 5 (1) ◽  
pp. 95-97 ◽  
Author(s):  
Mitsuru Sasaki ◽  
Junko Nishiyama ◽  
Munehiro Uchida ◽  
Kohtaro Goto ◽  
Kiyohiko Tajima ◽  
...  
Keyword(s):  
Supercritical Water ◽  
Amide Group ◽  
Hydroxyl Group

scholarly journals SÍNTESE E CARACTERIZAÇÃO DE UM NOVO COMPLEXO BIMETÁLICO DE Pd(II) CONTENDO O ANTIBIÓTICO OXITETRACICLINA

2018 ◽  
Vol 35 (4) ◽  
pp. 39
Author(s):  
Wendell Guerra ◽  
Ana Paula Soares Fontes ◽  
Elene Cristina Pereira-Maia
Keyword(s):  
Spectral Data ◽  
Binuclear Complex ◽  
Carbonyl Oxygen ◽  
Amide Group ◽  
Hydroxyl Group ◽  
Synthesis And Characterization

This article reports the synthesis and characterization of a new binuclear complex of palladium (II) containing the antibiotic oxytetracycline. The complex was characterized by the usual techniques of analysis. With respect to sites of coordination, the IR spectral data suggests the involvement the oxygen of the amide group and the oxygen of the neighbor hydroxyl group at ring A and to the carbonyl oxygen at C11 and the hydroxyl group at C12.

Supposed acetyl migration from the 3β- to the 19-hydroxyl group in Δ5-steroids

1974 ◽  
Vol 27 (2) ◽  
pp. 323 ◽  
Author(s):  
DR Baigent ◽  
KG Lewis
Keyword(s):  
Chemical Shifts ◽  
Hydroxyl Group ◽  
Ether Group ◽  
Acetyl Migration

The product of monotritylation of 3β,19-dihydroxyandrost-5-en-17-one is the 3β-trityl ether, not the 19-trityl ether as previously proposed. In consequence the product of acetylation of the monotrityl ether is 19-acetoxy-3β-trityloxyandrost-5-en-17-one and thus acid-catalysed detritylation of this compound yields directly the 19-acetoxy derivative without the invoking of an acid-catalysed rearrangement. The isomeric 3β-hydroxy-19-trityloxyandrost-5-en-17-one has been prepared as well as a number of 3β-tritylated Δ5-steroids which have been used to study the influence of the trityl ether group upon p.m.r. chemical shifts in this series.

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