Hydrolysis of Zirconium Propoxide by an Esterification Reaction

ABSTRACTZirconium propoxide hydrolysis was performed with the help of an esterification reaction using acetic acid. Products, obtained according to the value of hydrolysis ratio, are successively crystals, sols and gels or precipitates. The similarity of FUR and NMR spectra for crystals and gels allows to think that the arrangements of ligands around the zirconium atoms are close. The crystalline structure determination permits to precise the environment : acetate groups are always bridging and propoxy groups can be bridging or terminal. Clusters containing 9 zirconium atoms, bridged by oxygen atoms, exist in the structure. The colloid size growth was performed by light scattering. A discussion of the role of acetic acid and the competition between the possible reactions is given.

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Kinetics and Mechanism of Hydrolysis of Acetylthiocholine by Butyrylcholine Esterase

Zeitschrift für Naturforschung C ◽

10.1515/znc-2002-11-1221 ◽

2002 ◽

Vol 57 (11-12) ◽

pp. 1072-1077 ◽

Cited By ~ 4

Author(s):

Karel Komers ◽

Alexandr Čegan ◽

Marek Link

Keyword(s):

Acetic Acid ◽

Kinetics And Mechanism ◽

Kinetics Parameters ◽

Mechanism Of Hydrolysis ◽

Ph Stat ◽

Stat Method ◽

Ellman’S Method ◽

Hydrolysis Of

Kinetics and mechanism of hydrolysis of acetylthiocholine by the enzyme butyrylcholine esterase was studied. The spectrophotometric Ellman’s method and potentiometric pH-stat method were used for continuous determination of the actual concentration of the products thiocholine and acetic acid in the reaction mixture. The validity of the Michaelis-Menten (Briggs-Haldane) equation in the whole course of the reaction under used conditions was proved. The corresponding kinetics parameters (Vm and KM) were calculated from the obtained dependences of concentration of thiocholine or acetic acid vs. time and compared. From this comparison the deciding kinetic role of the step producing thiocholine was derived. The values of initial molar concentration of the enzyme and of the rate constants of the kinetic model were estimated.

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Study of structure and properties of platinum(II) chloride complexes with (2-alkyltetrazol-5-yl)acetic acid by quantum chemistry and NMR-spectroscopy methods

Journal of the Belarusian State University Chemistry ◽

10.33581/2520-257x-2019-2-3-11 ◽

2019 ◽

pp. 3-11

Author(s):

Vitaly E. Matulis ◽

Ekaterina G. Ragoyja ◽

Tatiyana V. Serebryanskaya ◽

Yuri V. Grigoriev ◽

Oleg A. Ivashkevich

Keyword(s):

Acetic Acid ◽

Nmr Spectroscopy ◽

Quantum Chemistry ◽

1H Nmr ◽

Nmr Spectra ◽

Structure And Properties ◽

Chloride Complexes ◽

Nmr Spectrum ◽

Hydrolysis Of ◽

Tetrazole Derivatives

It has been shown that the WP04 functional in combination with moderate basic sets 6-31G(d) and SDD allows to calculate characteristics of 1H NMR-spectrum of metal complexes with ligands based on tetrazole derivatives with high accuracy, which can be used to assign signals in the NMR-spectra. The process of hydrolysis of the isomeric platinum(II) chloride complexes with (2-isopropyltetrazol-5-yl)acetic acid has been investigated using the methods of quantum chemistry and NMR-spectroscopy. An explanation of the changes of signals in the 1H NMR-spectra of the considered complexes during their hydrolysis is given.

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Zur Chemie der 1,3,5-Triaza-2-phosphinan-4,6-dione, Teil IV. / Chemistry of the 1,3,5-Triaza-2-phosphinane-4,6-diones, Part IV.

Zeitschrift für Naturforschung B ◽

10.1515/znb-1993-0701 ◽

1993 ◽

Vol 48 (7) ◽

pp. 853-859 ◽

Cited By ~ 12

Author(s):

Michael Farkens ◽

Ion Neda ◽

Axel Fischer ◽

Peter G. Jones ◽

Reinhard Schmutzler

Keyword(s):

Structure Determination ◽

Mass Spectra ◽

Nmr Spectra ◽

X Ray ◽

Envelope Conformation ◽

Reaction With Water ◽

Hydrolysis Of

The 1,3,5-trimethyl-1,3,5-triaza-2-oxo-2λ4-phosphinane-4,6-diones 7 and 8 were obtained from the 6,8,10-trimethyl-2,2,3,3-tetrakis(trifluoromethyl)-6,8,10-triaza-1,4-dioxa-5 λ5-phosphaspiro[4.5]decane-7,9-diones 3 and 5, either by reaction with water or on heating; in the latter case we assume that tetrakis(trifluoromethyl)oxirane was eliminated. The hydrolysis of 2-(β-chloroethyl)amino-1,3,5-trimethyl-1,3,5-triaza-2-[p-nitrobenzoylimido]-2A4-phosphinane-4,6-dione 4 and of 5-bis-(β-chloroethyl)-amino-6,8,10-trimethyl-2,3-perchlorobenzo-6,8,10-triaza-1,4-dioxa-5λ5-phosphaspiro[4.5]decane-7,9-dione 6, in the same manner, gave the products 7 and 8. The synthesis of the perfluoropinacolyl spirophosphorane 3 is described. The compounds 3,7 and 8 were characterized from their 1H, 13C and 31P NMR spectra, mass spectra and through the X-ray structure determination of 8, in which the ring displays a flattened envelope conformation.

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Hydrolysis of O-Acetylsalicylic Acid (Aspirin) in Relation to the Aspirin-Bromate-Acid Oscillating System

Collection of Czechoslovak Chemical Communications ◽

10.1135/cccc20061445 ◽

2006 ◽

Vol 71 (10) ◽

pp. 1445-1452 ◽

Cited By ~ 1

Author(s):

Ľubica Adamčíková ◽

Daniel Mišicák ◽

Peter Ševčík

Keyword(s):

Acetic Acid ◽

Salicylic Acid ◽

Acetylsalicylic Acid ◽

Induction Period ◽

Rate Constant ◽

Degradation Products ◽

Oscillatory Behavior ◽

Active Substrate ◽

Hydrolysis Of

The uncatalyzed BrO3--O-acetylsalicylic acid (aspirin) reaction in aqueous H2SO4 exhibits oscillatory behavior. The induction period observed before the onset of oscillations depends on the extent of hydrolysis of aspirin. The rate constant of hydrolysis of aspirin was determined indirectly from the value of induction period. When aspirin undergoes hydrolysis, the degradation products are salicylic acid and acetic acid. Salicylic acid may play a role of "active" substrate responsible for the oscillations. Aspirin (Bayer) generates also oscillations with bromate.

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SYNTHESIS FOR NANOFLOWER AND ROD OF ZnO BY A SURFACTANT FREE AND LOW TEMPERATURE METHOD

Surface Review and Letters ◽

10.1142/s0218625x10013655 ◽

2010 ◽

Vol 17 (02) ◽

pp. 173-176 ◽

Cited By ~ 3

Author(s):

BYUNG SUN HAN ◽

YOUNG RANG UHM ◽

CHANG KYU RHEE

Keyword(s):

Acetic Acid ◽

Morphological Changes ◽

Distilled Water ◽

X Ray Diffraction ◽

Temperature Method ◽

Diffraction Patterns ◽

Rapid Hydrolysis ◽

Zno Powder ◽

Hydrolysis Of

ZnO with 2D flower-like and 1D rod shape were obtained from simple and rapid hydrolysis of Zn nanopowder. The Zn nanopowders were incorporated into distilled water with acetic acid and then the solution was stirred at 60°C for 8 h. The nanoflower-like and rod shape were formed without any surfactant. It seems that the acetic acid played a role of controlling PH and etching the oxide layer on the surface of metal nanopowders to enhance rapid reaction with distilled water. X-ray diffraction patterns for all samples exhibited that the resultant precipitates were completely transformed to ZnO powder. It is clearly observed that the morphological changes of ZnO with reaction time in aqueous solution follows chestnut bur → flower → tetrahedron → rod sequences during the hydrolysis reaction.

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Role of SOD in the protection of Rhizophora mangle on gastric injury induced by ethanol, ischaemia-reperfusion and acetic acid in rats

Planta Medica ◽

10.1055/s-0029-1234970 ◽

2009 ◽

Vol 75 (09) ◽

Cited By ~ 1

Author(s):

FM de-Faria ◽

A Luiz-Ferreira ◽

ACA Almeida ◽

V Barbastefano ◽

MA Silva ◽

...

Keyword(s):

Acetic Acid ◽

Rhizophora Mangle ◽

Gastric Injury ◽

Ischaemia Reperfusion

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Organic material dissolved during oxygen-alkali pulping of hot water extracted birch sawdust

TAPPI Journal ◽

10.32964/tj14.4.237 ◽

2015 ◽

Vol 14 (4) ◽

pp. 237-244 ◽

Cited By ~ 1

Author(s):

JONI LEHTO ◽

RAIMO ALÉN

Keyword(s):

Acetic Acid ◽

Betula Pendula ◽

Cooking Time ◽

Hot Water ◽

Partial Hydrolysis ◽

Chemical Pulping ◽

Black Liquors ◽

Aliphatic Carboxylic Acids ◽

Hydrolysis Of ◽

Cooking Conditions

Untreated and hot water-treated birch (Betula pendula) sawdust were cooked by the oxygen-alkali method under the same cooking conditions (temperature = 170°C, liquor-to-wood ratio = 5 L/kg, and 19% sodium hydroxide charge on the ovendry sawdust). The pretreatment of feedstock clearly facilitated delignification. After a cooking time of 90 min, the kappa numbers were 47.6 for the untreated birch and 10.3 for the hot water-treated birch. Additionally, the amounts of hydroxy acids in black liquors based on the pretreated sawdust were higher (19.5-22.5g/L) than those in the untreated sawdust black liquors (14.8-15.5 g/L). In contrast, in the former case, the amounts of acetic acid were lower in the pretreated sawdust (13.3-14.8 g/L vs. 16.9-19.1 g/L) because the partial hydrolysis of the acetyl groups in xylan already took place during the hot water extraction of feedstock. The sulfur-free fractions in the pretreatment hydrolysates (mainly carbohydrates and acetic acid) and in black liquors (mainly lignin and aliphatic carboxylic acids) were considered as attractive novel byproducts of chemical pulping.

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Directive Effect of Chain Length in Modulating Peptide Nano-assemblies

Protein and Peptide Letters ◽

10.2174/0929866527666200224114627 ◽

2020 ◽

Vol 27 (9) ◽

pp. 923-929

Author(s):

Gaurav Pandey ◽

Prem Prakash Das ◽

Vibin Ramakrishnan

Keyword(s):

Electron Microscopy ◽

Amino Acids ◽

Light Scattering ◽

Chain Length ◽

Self Assembly ◽

The Self ◽

Ionic Charge ◽

Self Assembling ◽

Biophysical Techniques

Background: RADA-4 (Ac-RADARADARADARADA-NH2) is the most extensively studied and marketed self-assembling peptide, forming hydrogel, used to create defined threedimensional microenvironments for cell culture applications. Objectives: In this work, we use various biophysical techniques to investigate the length dependency of RADA aggregation and assembly. Methods: We synthesized a series of RADA-N peptides, N ranging from 1 to 4, resulting in four peptides having 4, 8, 12, and 16 amino acids in their sequence. Through a combination of various biophysical methods including thioflavin T fluorescence assay, static right angle light scattering assay, Dynamic Light Scattering (DLS), electron microscopy, CD, and IR spectroscopy, we have examined the role of chain-length on the self-assembly of RADA peptide. Results: Our observations show that the aggregation of ionic, charge-complementary RADA motifcontaining peptides is length-dependent, with N less than 3 are not forming spontaneous selfassemblies. Conclusion: The six biophysical experiments discussed in this paper validate the significance of chain-length on the epitaxial growth of RADA peptide self-assembly.

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