Effect of OH- Concentration on Alkaline Hydrolysis of Diphenyl (4-Nitrophenyl) Phosphate Catalyzed by 2-Iodosobenzoic and 3-Iodoso-2-naphthoic Acids

1994 ◽  
Vol 59 (5) ◽  
pp. 1137-1144 ◽  
Author(s):  
Aleš Ptáček ◽  
Jiří Kulič
Keyword(s):  
Alkaline Hydrolysis ◽  
Reaction Rate ◽  
Ion Concentration ◽  
Molar Ratio ◽  
Hexadecyltrimethylammonium Bromide ◽  
Ph Values ◽  
Nitrophenyl Phosphate ◽  
Naphthoic Acid ◽  
Iodosobenzoic Acid ◽  
Hydrolysis Of

The hydrolysis of diphenyl (4-nitrophenyl) phosphate catalyzed by 2-iodosobenzoic and 3-iodoso-2-naphthoic acids has been studied at different pH values in the presence of hexadecyltrimethylammonium bromide as a micellar agent. It was found that 3-iodoso-2-naphthoic acid is better catalyst than 2-iodosobenzoic acid. At amounts of the acids higher than stoichiometric, the reaction is independent of pH in the 8.00 to 10.00 region while on using substoichiometric amounts, the reaction rate depends on OH- ion concentration only when the acid to diphenyl (4-nitrophenyl) phosphate molar ratio amounts to 12.5 : 1 for 2-iodosobenzoic acid and 6.25 : 1 for 3-iodoso-2-naphthoic acid.

Alkaline Hydrolysis of 4-Nitrophenyl Acetate and Diphenyl (4-Nitrophenyl) Phosphate Catalyzed by Iodosoarenesulfonic Acids

1994 ◽  
Vol 59 (6) ◽  
pp. 1392-1399 ◽  
Author(s):  
Jiří Kulič ◽  
Aleš Ptáček
Keyword(s):  
Alkaline Hydrolysis ◽  
Phenyl Acetate ◽  
Hexadecyltrimethylammonium Bromide ◽  
Nitrophenyl Phosphate ◽  
Hydrolysis Of

Alkaline hydrolysis of 4-nitrophenyl acetate and of diphenyl (4-nitrophenyl) phosphate catalyzed by 2-iodosobenzenesulfonic and 2-iodoso-1-naphthalenesulfonic acids was studied in the presence of hexadecyltrimethylammonium bromide as the micellar agent. It was found that 2-iodosobenzenesulfonic acid is the better catalyst for the hydrolysis of phenyl acetate while 2-iodoso-1-naphthalenesulfonic acid is more efficient for the hydrolysis of the phosphate.

Catalyzed Alkaline Hydrolysis of Substituted Phenyl Acetates

1993 ◽  
Vol 58 (8) ◽  
pp. 1798-1802 ◽  
Author(s):  
Jiří Kulič ◽  
Aleš Ptáček
Keyword(s):  
Alkaline Medium ◽  
Alkaline Hydrolysis ◽  
Rate Constants ◽  
Hexadecyltrimethylammonium Bromide ◽  
Hammett Equation ◽  
First Order ◽  
Order Rate ◽  
Iodosobenzoic Acid ◽  
Hydrolysis Of

2-Iodosobenzoic acid forming strong nucleophile in alkaline medium - 1-oxido-1,2-benziodoxol-3(1H)-one, was used as a catalyst of alkaline hydrolysis of substituted phenyl acetates (4-NO2, 3-NO2, 3-Cl, 4-Br, H, 4-CH3, 3-CH3, 4-OCH3, 3-OCH3) in the presence of hexadecyltrimethylammonium bromide as a micellar agent. It was found that the observed first-order rate constants kobs can be correlated by the Hammett equation: log kobs = (-3.29 ± 0.03) + (1.77 ± 0.001) σ.

scholarly journals Phosphatase synthesis in Klebsiella (Aerobacter) aerogenes growing in continuous culture

1972 ◽  
Vol 127 (1) ◽  
pp. 87-96 ◽  
Author(s):  
P. G. Bolton ◽  
A. C. R. Dean
Keyword(s):  
Alkaline Phosphatase ◽  
Acid Phosphatase ◽  
Continuous Culture ◽  
Activity Profile ◽  
Glucose Effect ◽  
Ph Values ◽  
Nitrophenyl Phosphate ◽  
Wide Range ◽  
Rate Of Hydrolysis ◽  
Hydrolysis Of

1. Phosphatase synthesis was studied in Klebsiella aerogenes grown in a wide range of continuous-culture systems. 2. Maximum acid phosphatase synthesis was associated with nutrient-limited, particularly carbohydrate-limited, growth at a relatively low rate, glucose-limited cells exhibiting the highest activity. Compared with glucose as the carbon-limiting growth material, other sugars not only altered the activity but also changed the pH–activity profile of the enzyme(s). 3. The affinity of the acid phosphatase in glucose-limited cells towards p-nitrophenyl phosphate (Km 0.25–0.43mm) was similar to that of staphylococcal acid phosphatase but was ten times greater than that of the Escherichia coli enzyme. 4. PO43−-limitation derepressed alkaline phosphatase synthesis but the amounts of activity were largely independent of the carbon source used for growth. 5. The enzymes were further differentiated by the effect of adding inhibitors (F−, PO43−) and sugars to the reaction mixture during the assays. In particular, it was shown that adding glucose, but not other sugars, stimulated the rate of hydrolysis of p-nitrophenyl phosphate by the acid phosphatase in carbohydrate-limited cells at low pH values (<4.6) but inhibited it at high pH values (>4.6). Alkaline phosphatase activity was unaffected. 6. The function of phosphatases in general is discussed and possible mechanisms for the glucose effect are outlined.

Alkaline Hydrolysis of Substituted Phenyl Acetates Catalyzed by Quaternary Ammonium Salts

1993 ◽  
Vol 58 (12) ◽  
pp. 2891-2895 ◽  
Author(s):  
Jiří Kulič ◽  
Jiří Sussenbek ◽  
Aleš Ptáček
Keyword(s):  
Ammonium Chloride ◽  
Alkaline Hydrolysis ◽  
Quaternary Ammonium Salts ◽  
Ammonium Salts ◽  
Ammonium Bromide ◽  
Hexadecyltrimethylammonium Bromide ◽  
Rate Data ◽  
Hammett Equation ◽  
Efficient Catalyst ◽  
Hydrolysis Of

Alkaline hydrolysis if the phenyl acetates CH3COOC6H4X (X = 4-NO2, 3-NO2, 3-Cl, H, 4-CH3, 3-CH3, and 4-OCH3) in the presence of hexadecyltris(2-hydroxyethyl)ammonium chloride, bis(2-hydroxyethyl)hexadecyl(methyl)ammonium bromide, and hexadecyltrimethylammonium bromide has been studied. Comparison of the rates of the hydrolysis for the above tenzides showed that the most efficient catalyst is the hexadecyltris(2-hydroxyethyl)ammonium chloride. In all cases, the rate data correlated well with structure effects by the Hammett equation.

Preparation of a new metallomicelle catalyst for the hydrolysis of bis(4-nitrophenyl) phosphate

2013 ◽  
Vol 67 (4) ◽  
Author(s):  
Jia-Qing Xie ◽  
Ci Li ◽  
Min Wang ◽  
Bing-Ying Jiang
Keyword(s):  
Reaction Rate ◽  
Active Species ◽  
Local Concentration ◽  
Catalytic Hydrolysis ◽  
Catalytic Function ◽  
Nitrophenyl Phosphate ◽  
Spontaneous Hydrolysis ◽  
Lauryl Ether ◽  
Hydrolysis Of ◽  
Bnpp Hydrolysis

AbstractA new metallomicellar system containing cerium(III), a macrocylic polyamine ligand, and the nonionic surfactant Brij35(polyoxyethylene(23) lauryl ether) was prepared and used as a catalyst in the hydrolysis of bis(4-nitrophenyl) phosphate (BNPP). Catalytic rate of the BNPP hydrolysis was measured kinetically using the UV-VIS spectrophotometric method. The results indicate that the metallomicellar system has relatively high stability and excellent catalytic function in the BNPP hydrolysis; also, the reaction rate of the BNPP catalytic hydrolysis increased by a factor of ca. 1 × 1010 compared to the BNPP spontaneous hydrolysis due to the catalytic effect of the active species and the local concentration effect of the micelles in the metallomicellar system. Experimental results also showed that the mono-hydroxy complex containing the macrocyclic polyamine ligand and cerium(III) is the real active species in the BNPP catalytic hydrolysis, and that the micelles provide a useful catalytic environment for the reaction. On basis of the research results, the reaction mechanism of BNPP catalytic hydrolysis has been proposed.

scholarly journals In Vitro Study of MefenamateStarch as Drug Delivery System

2013 ◽  
Vol 10 (3) ◽  
pp. 954-964
Author(s):  
Baghdad Science Journal
Keyword(s):  
In Vitro Study ◽  
Controlled Drug Release ◽  
Gastric Fluid ◽  
Molar Ratio ◽  
Ph Values ◽  
Ft Ir ◽  
Uv Visible ◽  
The Stability ◽  
Hydrolysis Of

Mefenamic acid was esterified with starchwith[1:1] Molar ratio, as drug substituted with natural polymer, to prolongthe period of hydrolysis of drug polymer with other advantages. The new prodrug starch was characterized by FT-IR and UV-Visible and 1H-NMR spectroscopies. The physical properties were studied and controlled drug release was studied in different pH values at 37oC. The stability of drug was carried out by measuring the absorbance of mefenamic starch which hydrolyzed in HCl solution of pH 1.1 (artificial gastric fluid) and phosphate buffer of pH 7.4 (simulating intestinal fluid SIF) at 37oC for several days. The thermal analysis such as DSC was studied.

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