scholarly journals Oxidation–reduction reactions of simple hydroxamic acids and plutonium(IV) ions in nitric acid

2008 ◽  
Vol 96 (6) ◽  
Author(s):  
M. J. Carrott ◽  
O. D. Fox ◽  
G. LeGurun ◽  
C. J. Jones ◽  
C. Mason ◽  
...  
Keyword(s):  
Acid Hydrolysis ◽  
Kinetic Studies ◽  
Hydroxamic Acids ◽  
Single Cycle ◽  
Fuel Cycles ◽  
Oxidation Reduction ◽  
Advanced Fuel ◽  
Extraction Processes ◽  
The Stability ◽  
Hydrolysis Of

SummarySimple hydroxamic acids such as formo- and aceto-hydroxamic acids have been proposed as suitable reagents for the separation of either Pu and/or Np from U in modified or single cycle Purex based solvent extraction processes designed to meet the emerging requirements of advanced fuel cycles. The stability of these hydroxamic acids is dominated by their decomposition through acid hydrolysis. Kinetic studies of the acid hydrolysis of formo- and aceto-hydroxamic acids are reported in the absence and the presence of Pu(IV) ions. The slow reduction of these plutonium(IV) hydroxamate complexes to Pu(III) aquo-ions has been characterised by spectrophotometry and cyclic voltammetry. The reductions of Pu(IV) in the presence of FHA and AHA are consistent with a mechanism in which free hydroxamic acid in solution is hydrolysed whilst Pu(IV) ions remain fully complexed to hydroxamate ligands; then at some point close to a 1 : 1 Pu(IV) : XHA ratio, some free Pu

scholarly journals Kinetic studies on the acid hydrolysis of the methyl ketoside of unsubstituted and O-acetylated N-acetylneuraminic acid

1973 ◽  
Vol 133 (4) ◽  
pp. 623-628 ◽  
Author(s):  
A. Neuberger ◽  
Wendy A. Ratcliffe
Keyword(s):  
Sialic Acid ◽  
Acid Hydrolysis ◽  
Model Compound ◽  
Kinetic Studies ◽  
Order Rate Constant ◽  
Neuraminic Acid ◽  
Acetylneuraminic Acid ◽  
Rate Of Hydrolysis ◽  
Ph Range ◽  
Hydrolysis Of

The hydrolysis of the model compound 2-O-methyl-4,7,8,9-tetra-O-acetyl-N-acetyl-α-d-neuraminic acid and neuraminidase (Vibrio cholerae) closely resembled that of the O-acetylated sialic acid residues of rabbit Tamm–Horsfall glycoprotein. This confirmed that O-acetylation was responsible for the unusually slow rate of acid hydrolysis of O-acetylated sialic acid residues observed in rabbit Tamm–Horsfall glycoprotein and their resistance to hydrolysis by neuraminidase. The first-order rate constant of hydrolysis of 2-methyl-N-acetyl-α-d-neuraminic acid by 0.05m-H2SO4 was 56-fold greater than that of 2-O-methyl-4,7,8,9-tetra-O-acetyl-N-acetyl -α-d-neuraminic acid. Kinetic studies have shown that in the pH range 1.00–3.30, the observed rate of hydrolysis of 2-methyl-N-acetyl-α-d-neuraminic acid can be attributed to acid-catalysed hydrolysis of the negatively charged CO2− form of the methyl ketoside.

Kinetic studies of two-stage sulphuric acid hydrolysis of sugarcane bagasse

2015 ◽  
Vol 83 ◽  
pp. 850-858 ◽  
Author(s):  
Sachin Kumar ◽  
Pratibha Dheeran ◽  
Surendra P. Singh ◽  
Indra M. Mishra ◽  
Dilip K. Adhikari
Keyword(s):  
Acid Hydrolysis ◽  
Sulphuric Acid ◽  
Sugarcane Bagasse ◽  
Kinetic Studies ◽  
Two Stage ◽  
Hydrolysis Of

Influence of Deacidification on Arylmethane Dyes on Paper

2015 ◽  
Vol 36 (3) ◽  
Author(s):  
Viera Jančovičová ◽  
Eva Belányiová ◽  
Zuzana Machatová ◽  
Bohuslava Havlínová
Keyword(s):  
Relative Humidity ◽  
Acid Hydrolysis ◽  
Aqueous Extract ◽  
Mass Scale ◽  
Accelerated Ageing ◽  
Colour Difference ◽  
Historic Paper ◽  
The Stability ◽  
The Impact ◽  
Hydrolysis Of

AbstractThe deacidification of historic paper objects has evolved into a method that is applied in mass-scale in some archives and libraries. While the impact of the deacidification reagents on paper is quite well researched, knowledge about the behavior of colours and dyes is more limited. Our study focused on the influence of paper deacidification by the Book Saver® process on eight different dyes applied on paper, as well as on the paper support itself. Accelerated ageing in moist and warm conditions (80°C, 65% relative humidity) was applied to investigate the stability of the dye layer on top of the paper, with respect to their chemical, optical and spectroscopic attributes. The Book® deacidification process increased the pH of the aqueous extract and an alkaline reserve was created. FTIR spectroscopic measurements showed that deacidification suppresses acid hydrolysis of paper. The variations in UV-Vis reflectance spectra and in total colour difference of the dye layer evidenced the changes in the structure of dyes caused by accelerated ageing, but the extent of the changes differs depending on the dye. We can conclude that some dyes are more prone to changes by deacidification than others.

Thiohydantoins. X. Kinetic Studies of the Acid Hydrolysis of 1-Acyl-2-thiohydantoins

1972 ◽  
Vol 50 (23) ◽  
pp. 3767-3779 ◽  
Author(s):  
Wayne Irvine Congdon ◽  
John Thomas Edward
Keyword(s):  
Sulfuric Acid ◽  
Carboxylic Acid ◽  
Acid Hydrolysis ◽  
Kinetic Studies ◽  
Steric Effects ◽  
Aqueous Sulfuric Acid ◽  
Hydrolysis Of

The rates of hydrolysis of 22 1-acyl-2-thiohydantoins in aqueous sulfuric acid to give 2-thiohydantoin and a carboxylic acid have been determined. In 0–90% sulfuric acid, hydrolysis takes place by an A-2 mechanism, and the rate reaches a maximum in about 70% acid. In acid more concentrated than about 90%, hydrolysis takes place by an A-1 mechanism, and the rate increases monotonically. Evidence for the two mechanisms comes from Yates r and Bunnett-Olsen [Formula: see text] parameters; from entropies of activation; from pσ and pσ+ relations; and from steric effects.

The Acid Hydrolysis of Egg Albumin. I. Kinetic Studies

1948 ◽  
Vol 70 (6) ◽  
pp. 2128-2131 ◽  
Author(s):  
Henry B. Bull ◽  
J. Wilfrid Hahn
Keyword(s):  
Acid Hydrolysis ◽  
Kinetic Studies ◽  
Egg Albumin ◽  
Hydrolysis Of

scholarly journals Kinetic Studies of Acid Hydrolysis of Food Waste-Derived Saccharides

2018 ◽  
Vol 57 (51) ◽  
pp. 17365-17374 ◽  
Author(s):  
Elvis Ebikade ◽  
Jonathan Lym ◽  
Gerhard Wittreich ◽  
Basudeb Saha ◽  
Dionisios G. Vlachos
Keyword(s):  
Acid Hydrolysis ◽  
Food Waste ◽  
Kinetic Studies ◽  
Hydrolysis Of

Septanose Carbohydrates. III. Oxidation-Reduction Products From 1,2-3,4-Di-O-isopropylidene-α-D-glucoseptanose: Preparation of L-Idose Derivatives

1990 ◽  
Vol 43 (12) ◽  
pp. 2063 ◽  
Author(s):  
GE Driver ◽  
JD Stevens
Keyword(s):  
Acetic Anhydride ◽  
Dimethyl Sulfoxide ◽  
Acid Hydrolysis ◽  
Sodium Methoxide ◽  
Aqueous Acid ◽  
Methylmagnesium Iodide ◽  
Oxidation Reduction ◽  
Hydrolysis Of

Oxidation of 1,2:3,4-di-O-isopropylidene-α-D-glucoseptanose (1a) with dimethyl sulfoxide and acetic anhydride has yielded methylthiomethyl ether (1b), ketone (2), and a novel product (3). Reduction of (2) gave (1a) and its L-ido isomer (4a) which yielded the mono-O-isopropylidene compound (5a) on aqueous acid hydrolysis. Treatment of (5a) with acidified acetone gave (4a) and 1,2:4,5-di-O-isopropylidene-β-L- idoseptanose (7a). Reaction of (2) with methylmagnesium iodide yielded the two 5-C-methyl compounds (8) and (9). Hydrolysis of (8) and (9) gave 5-C-methyl-D-glucose (10) and 5-C-methyl-L-idose (11), respectively, as crystalline compounds which yielded crystalline pentaacetates on acetylation. Treatment of the p-toluenesulfonate (1c) with lithium benzoate in dimethylformamide gave the benzoate of (4a) and an elimination product (17). Reaction of (1c) with sodium methoxide in methanol yielded (17) and the isomeric elimination product (18).

Sign in / Sign up

Export Citation Format

Share Document