Kinetics and solvent effects in the acid hydrolysis of potassium ethyl malonate in dioxane-water and acetone-water mixtures

1977 ◽  
Vol 108 (2) ◽  
pp. 469-475 ◽  
Author(s):  
Fayez Y. Khalil ◽  
Hussein Sadek ◽  
M. T. Hanna
Keyword(s):  
Acid Hydrolysis ◽  
Solvent Effects ◽  
Acetone Water ◽  
Ethyl Malonate ◽  
Hydrolysis Of

Alkaline hydrolysis of glycol esters - A newly suggested criterion in the assessment of anchimeric assistance

1974 ◽  
Vol 27 (11) ◽  
pp. 2325 ◽  
Author(s):  
M Balakrishnan ◽  
Rao G Venkoba ◽  
N Venkatasubramanian
Keyword(s):  
Transition State ◽  
Solvent Effects ◽  
Alkaline Hydrolysis ◽  
Triethylene Glycol ◽  
Binary Solvent ◽  
Solvent Mixtures ◽  
Acetone Water ◽  
Anchimeric Assistance ◽  
Hydrolysis Of ◽  
Suggested Criterion

Solvent effects vis a vis structural effects on the alkaline hydrolysis of various di-and mono-benzoates of glycols have been studied in binary solvent mixtures of dimethyl sulphoxide-water, ethanol-water and acetone-water. It is observed that the higher the stabilization of the transition state by the neighbouring group, the greater is the susceptibility of the reaction to dipolar aprotic solvent acceleration[i.e. k(Me2SO)/k(EtOH) value]. The possibility of employing such solvent effects to evaluate the extent of anchimeric assistance in ester hydrolysis where the neighbouring group can stabilize the transition state is examined. The studies have been extended to triethylene glycol derivatives and it is suggested that dipolar aprotic-protic solvent effects could be used as a kinetic probe for the conformation of the molecule.

Kinetic order with respect to solvent: Acid hydrolysis and preferential solvation of the Reineckate ion

1967 ◽  
Vol 45 (24) ◽  
pp. 3049-3053 ◽  
Author(s):  
Cooper H. Langford ◽  
John F. White
Keyword(s):  
Acid Hydrolysis ◽  
Preferential Solvation ◽  
Solvation Shell ◽  
Resonance Technique ◽  
Kinetic Order ◽  
Solvent Water ◽  
Acetone Water ◽  
Magnetic Resonance Technique ◽  
Hydrolysis Of

The nuclear magnetic resonance technique of preferential solvation analysis developed by Frankel, Stengle, and Langford is applied to determination of the composition of the solvation shell about trans-[Cr(NH3)2(NCS)4]− in acetone–water mixtures. The composition of the solvation shell is correlated with the rate of acid hydrolysis of the chromium complex. It emerges that the solvolysis reaction is second order with respect to the solvolytically reactive solvent, water. The mechanistic implications of the rate law are considered as is the significance of analysis of preferential solvation for the determination of kinetic order of solvolytic reactions.

The Acid Hydrolysis of Ethyl Dichloroacetate in Acetone-Water Solvent1

1955 ◽  
Vol 77 (13) ◽  
pp. 3452-3453 ◽  
Author(s):  
P. Madhavan Nair ◽  
Edward S. Amis
Keyword(s):  
Acid Hydrolysis ◽  
Acetone Water ◽  
Hydrolysis Of

DETERMINATION OF MICRO-AMOUNTS OF 5β-PREGNAN-3α-OL-20-ONE IN URINE USING INFRARED-SPECTROMETRY

1962 ◽  
Vol 41 (2) ◽  
pp. 234-246 ◽  
Author(s):  
H. J. van der Molen
Keyword(s):  
Infrared Spectrum ◽  
Quantitative Determination ◽  
Acid Hydrolysis ◽  
Chromatographic Separation ◽  
Pure Form ◽  
Infrared Spectrometry ◽  
Hydrolysis Of

ABSTRACT A procedure for the quantitative determination of 5β-pregnan-3α-ol-20-one in urine is described. After acid hydrolysis of the pregnanolone-conjugates in urine, the free steroids are extracted with toluene. Pregnanolone is isolated in a pure form as its acetate; after chromatographic separation of the free steroids on alumina, the fraction containing pregnanolone is acetylated and rechromatographed on alumina. Quantitative determination of the isolated pregnanolone-acetate is carried out with the aid of the infrared spectrum recorded by a micro KBr-wafermethod. The reliability of the method under various conditions is discussed under the headings, specificity, accuracy, precision and sensitivity. It is possible to determine 30–40 μg pregnanolone in a 24-hours urine portion with a precision of 25%.

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