Hydrolysis Of P-nitrophenyl Diphenyl Phosphate Research Articles

Enhanced catalytic activity of o-iodosobenzoate in poly[(styrylmethyl)hexadecyldimethylammonium chloride] latexes for the hydrolysis of p-nitrophenyl diphenyl phosphate

Six 5.0 mol% crosslinked poly[(styrylmethyl)hexadecyldimethylammonium chloride] latexes containing 8–67% quaternization were synthesized via two-stage process and used as supports for o-iodosobenzoate (IBA) catalyst in the hydrolysis of model organophosphate compound p-nitrophenyl diphenyl phosphate (PNPDPP). The hydrodynamic diameters of the cationic latexes were less than 200 nm. The rate of the hydrolysis of PNPDPP greatly increased in the presence of the cationic latex particles and strongly depended on the degree of quaternization and amount of the latex as well as pH, type of buffer, and ionic strength of the medium. As the quaternization percentage of the latexes increased, the rates of the hydrolysis increased. The pseudo-first-order and second-order-rate constants of the hydrolysis reaction carried out with different amounts and type of cationic latexes at pH 7.0, 8.0 and 9.0 in different buffer solutions at 25 °C were determined. 1.0 × 10 −5 M IBA in 0.25 mg/mL of QL-67 latex enhanced the rate of the hydrolysis of 1.0 × 10 −5 M PNPDPP about 5670 times in TAPS buffered solution at pH 8.0 compared to the one in buffered solution and 1590 times in the presence of IBA alone in TAPS buffered solution. The highest second-order-rate constant k cat of 21200 ± 1100 M −1 s −1 was obtained when 0.25 mg/mL of QL-67 was employed in the hydrolysis reaction at pH 8.0.

PHYSICAL CHEMICAL STUDIES OF THE SURFACTANT DILAURYLDIMETHYLAMMONIUM BROMIDE (DLDMAB): AGGREGATION AND CATALYTIC PROPERTIES

The micellization of dilauryldimethylammonium bromide (DLDMAB) in water was studied by using surface tension measurements. The critical micellar concentration (CMC) was determined at 25°C, 32°C and 40°C and thermodynamic parameters such as the free energy of micellization (∆G°mic), enthalpy (∆H°mic), and entropy (∆S°mic) of micellization were measured. The CMC at 25°C was 4.93 x 10-5 M and the corresponding values of the thermodynamic parameters were: ∆G°mic = -5.87 kcal/mol; ∆H°mic = -1.12 kcal/mol and ∆S°mic = +16.00 e.u. Micelles of the surfactant DLDMAB act as catalysts for the alkaline hydrolysis of p-nitrophenyl diphenyl phosphate (NPDPP) with a maximum catalytic factor of approximately 120 compared to 80 for CTAB. Typical activation parameters measured for 1.00 x 10-3 M surfactant and 0.005 M NaOH were: Ea = 9.7 kcal/mo/; ∆H°≠ = 9.1 kcal/mol; ∆G°≠ = 19.6 kcal/mol and ∆S°≠ = -33.9 e.u. The kinetic results were also analyzed in terms of the pseudo-phase ion-exchange models (PPIE) and showed that the model is applicable to describe the experimental results.

MICELLAR CATALYZED REACTION IN AQUEOUS GLYCEROL SOLUTIONS AND THE INTERNAL PRESSURE OF THE MEDIUM

The experimental results obtained/or the hydrolysis of p-nitrophenyl diphenyl phosphate (NPDPP) in the presence of sodium hydroxide (NaOH), micelles of cetyltrimethylammonium bromide (CTAB), and an aqueous solution of glycerol were analyzed taking into consideration the internal pressure and the cohesive forces of the reaction medium. The effect of glycerol on mice/le formation and also its influence on the internal pressure of the reaction medium are large enough to affect the micellar catalyzed alkaline hydrolysis of the phosphate ester.

Preparation of cationic latexes with different length alkyl groups on their quaternary ammonium ions and their use as supports for IBA catalyst in the hydrolysis of PNPDPP

In this study, four cationic latexes containing n-hexadecyl, n-octyl, or a methyl group as one of the alkyls on their quaternary ammonium ions were synthesized and used as supports for o-iodosobenzoate (IBA) catalyst in the hydrolysis of p-nitrophenyl diphenyl phosphate (PNPDPP). The quaternary ammonium ions of the latexes were utilized to bind IBA anion electrostatically. In the kinetics of the hydrolysis of PNPDPP, first-order rate constants ( k obsd) of the reaction were determined by varying the type of latex, its amount, and the concentration of IBA at pH 7.0, 8.0, and 9.0 at 25 °C. Thereafter, the second-order rate constants ( k cat) were calculated for some of the reactions. Changing one of the alkyl groups of the quaternary ammonium ions of the latexes in the order of methyl, n-octyl, and n-hexadecyl yielded higher catalytic activities. For the most active IBA/latex catalyst, k obsd and k cat values were determined to be 3.28 × 10 −2 s −1 and 652 M −1 s −1 at pH 9.0 and 25 °C for the PNPDPP hydrolysis, respectively.

Effect of Heteroatom Insertion at the Side Chain of 5-Alkyl-1H-tetrazoles on Their Properties as Catalysts for Ester Hydrolysis at Neutral pH

[reaction: see text] Herein we introduce tetrazole and its suitably designed derivatives as powerful ester-cleaving reagents. By first performing a detailed ab initio computational study, we found that, in the side chain of 5-alkyl-1H-tetrazoles, introduction of a heteroatom (e.g., N, O, or S at the alpha-position of the tetrazole ring) raises the charge on the tetrazole nucleus significantly. All calculations have been performed using restricted Hartree-Fock (RHF) and hybrid ab initio/DFT (B3LYP) methods employing 6-31G* and 6-31+G* basis sets. To estimate the nucleophilicity of these reagents, the charges on conjugate bases of various tetrazole derivatives have been calculated using natural population (NBO) analysis in gas phase and in water. Free energy of protonation (fep) of the 1H-tetrazole derivatives (1-7), free energy of solvation, deltaG(aq), and the corresponding pKa values have been calculated by self-consistent reaction field (SCRF) methods applying the polarized continuum model (PCM). Since the calculation indicates that incorporation of heteroatom leads to enhanced nucleophilicity in their deprotonated anionic tetrazole forms, a series of 5-substituted 1H-tetrazole derivatives have been synthesized. These compounds indeed catalyze the hydrolysis of p-nitrophenyl diphenyl phosphate (PNPDPP) and p-nitrophenyl hexanoate (PNPH) efficiently in cationic cetyl trimethylammonium bromide (CTABr) micelles at pH 7.0 and 25 degrees C. The pseudo-first-order rate constants (k(obs)) were determined for each catalyst against both substrates. The experimental and theoretical results show that, to achieve better k(obs) values for the cleavage of PNPDPP and PNPH under micellar conditions, charge on the N- atom (nucleophile) of conjugate base is important. Replacing the alpha-CH2 in alkyl substituent with S (3), NH (4), or O (5) enhances the accumulation of charge on N- in conjugate bases of tetrazoles and subsequently increases their intrinsic nucleophilic reactivity toward hydrolytic reactions. Significantly large rate enhancements were observed for the cleavage of PNPDPP and PNPH at pH 7.0 in the presence of catalytic system 5/CTABr over background (only CTABr). Tetrazole 4 (alpha-isomer) showed 4-5-fold superior reactivity over 6 (beta-isomer) under identical conditions. Natural charges obtained from NBO analysis (B3LYP/6-31+G*) are -0.94 and -0.852 on N- in the conjugate bases of 4 and 6, respectively. This also predicts that 4 is a better nucleophile than 6. All the newly synthesized tetrazole derivatives in micellar media display true catalytic properties by cleaving several fold excess of substrates.

Ester Cleavage Properties of Synthetic Hydroxybenzotriazoles in Cationic Monovalent and Gemini Surfactant Micelles

Four new hydroxybenzotriazole derivatives have been synthesized. Two of them, N-tetradecyl-1-hydroxy-1H-benzo[d][1,2,3]triazole-6-carboxamide (2) and N-tetradecyl-1-hydroxy-1H-benzo[d][1,2,3]triazole-7-carboxamide (3), possess long alkyl chains, while the other two, 1-hydroxy-1H-benzo[d][1,2,3]triazole-6-carboxylic acid (4) and 1-hydroxy-1H-benzo[d][1,2,3]triazole-7-carboxylic acid (5), have carboxylate side chains. These compounds along with their parent unsubstituted 1-hydroxybenzotriazole (HOBt), 1, have been examined for the cleavage of p-nitrophenyl hexanoate (PNPH) and p-nitrophenyl diphenyl phosphate (PNPDPP) in comicelles with monovalent cetyltrimethylammonium bromide (CTABr) and the corresponding bis-cationic gemini surfactants 16-m-16, 2Br(-) of identical chain length at 25 degrees C and pH 8.2. The apparent pK(a) values of the HOBt derivatives in the comicelles of CTABr or 16-4-16 gemini surfactant have been determined from the rate versus pH profiles and were found to be comparable. Catalytic system 4/16-4-16 demonstrated over 2200- and 1650-fold rate enhancements in the hydrolysis of PNPDPP and PNPH, respectively, for identical reactions carried out at pH 8.2 and 25 degrees C in buffered aqueous media. The second-order rate constants for such bimolecular reactions were determined employing pseudophase micellar models. Experiments in which excess substrate was taken over HOBt derivatives demonstrated that the catalysts "turned over"; hydrolysis of the putative acylated or phosphorylated HOBt intermediates was rapid in either type of host micelles.

PHYSICAL CHEMICAL STUDIES OF THE AGGREGATION AND CATALYTIC PROPERTIES OF THE SURFACTANT CETYLDIMETHYLETHYLAMMONIUM BROMIDE (CDEAB)

The micellization of cetyldimethylethylammonium bromide (CDEAB) in water was studied by means of surface tensiometry. The critical micellar concentration (CMC) was determined at 25°, 32°, and 40°C, and thermodynamic properties such as the free energy of micellization (∆G°mic), enthalpy (∆H°mic) and entropy (∆S°mic) of micellization were measured. The CMC at 25°C was 9.05 x 10-4 M and the corresponding values of the thermodynamic parameters were: ∆G°mic = -4.15 kcal/mol; ∆H°mic = -1.37 kcal/mol and ∆S°mic = + 9.33 e.u. Micelles of the surfactant CDEAB were good catalysts for the alkaline hydrolysis of p-nitrophenyl diphenyl phosphate (NPDPP) with a maximum catalytic factor of approximately 80, comparable to that of CTAB. Typical activation parameters measured for 0.005 M NaOH were: Ea = 9.0 kcal/mol; ∆H°≠ = 8.4 kcal/mol; ∆G°≠ = 19.2 kcal/mol and ∆S°≠ = -36.3 e.u. The kinetic results were also analyzed in terms of the pseudo-phase ion-exchange models (PPIE) and showed that the model is applicable and gave reasonable fits

Long chain ß-aminoethanols as micellar catalysts for the hydrolysis of diphenyl-p-nitrophenyl phosphate. The observation of an unusual enhancement of catalysis in the presence of added polyols

The hydrolysis of p-nitrophenyldiphenyl phosphate (PNPDPP, 7) catalyzed by N-dodecylaminoethanol (6a), N-tetradecylaminoethanol (6b), N-methyl-N-tetradecylaminoethanol (6c), and N-hexadecylaminoethanol (6d) was investigated at 25°C at various pH values in aqueous media containing additives. Added ethanol or dimethoxyethane produces very little activity of 6a, b, c toward 7. The highest activities of 6a, b were found at pH 8.0 and 8.5 in solvents containing 20% glycerol or ethylene glycol. Under no conditions was N-hexadecylaminoethanol (6d) found to be active. The kinetics of the reaction of 6b with 7 were also investigated in a medium containing various amounts of glycerol, polyethylene glycol 400 (PEG 400), and water at pH 7.6-8.5. The best catalytic system comprised 3 mM 6b in 20% aqueous ethylene glycol, pH 8.5, which accelerated the hydrolysis of 7 by 1700-fold over the blank rate. Kinetic experiments conducted using [7]/[6b] = 1 and 2 demonstrate that 6b exhibits true turnover catalysis. A mechanism for the catalyzed reaction is proposed.Key words: ß-aminoethanols, hydrolysis, p-nitrophenyldiphenyl phosphate, micelles, polyhydroxy alcohols.

Poly(propylene imine) dendrimer complexes of Cu(II), Zn(II), and Co(III) as catalysts of hydrolysis ofp-nitrophenyl diphenyl phosphate

Poly(propylene imine) dendrimers having 8, 32, and 64 primary amine end groups form diamino Cu(II), diamino Zn(II), and tetramino Co(III) complexes that are identified spectrophotometrically and titrimetrically. The dendrimer-metal ion complexes catalyze the hydrolysis of p-nitrophenyl diphenyl phosphate in zwitterionic buffer solutions at pH Zn(II) > Co(III). The rates of hydrolysis are faster with sodium perchlorate than with sodium chloride to control ionic strength. In sodium perchlorate solutions with Cu(II) the rates increase with increasing size of the dendrimer. In sodium chloride solutions with Cu(II) the rates decrease with increasing size of the dendrimer. Rate constants in buffered sodium chloride solutions of dendrimers and 1.0mM Cu(II) are 1.3-6.3 times faster than in the absence of Cu(II). The fastest hydrolyses occurred at a dendrimer primary amine to Cu(II) ratio NH 2 /Cu ≤ 2. At NH 2 /Cu = 4 and with the 1,4,7,10-tetraazacyclodecane complex of Cu(II) hydrolysis rates were much slower.

Micellar-catalyzed reactions of a phosphate ester: effect of the dielectric constant of the medium

The hydrolysis of p-nitrophenyl diphenyl phosphate was studied in aqueous solutions containing micelles of cetyltrimethylammonium bromide (CTAB), sodium hydroxide and various concentrations of dimethylsulfoxide (DMSO). Pseudo first-order ( k ψ) and second-order ( k 2) rate constants were determined at 15, 25 and 35°C and activation parameters were also measured. The rate profiles obtained for solutions containing 10–50% DMSO by volume exhibited clear maxima that shifted to higher concentrations of CTAB as a function of DMSO added. For solutions containing 60–80% DMSO by volume there was no maximum in the rate profile and the reaction was inhibited. Solutions containing 90% DMSO by volume exhibited much higher reaction rates and considerably more catalysis. In the absence of surfactant a linear relationship is obtained between log k ψ and the Lorentz function of the dielectric constant of the binary mixtures DMSO–H 2O. When CTAB is added to the reaction medium there are two different situations. Beyond the formation of the hydrate DMSO·2H 2O, which inhibits the CTAB micellization, the results are identical to those obtained in the systems with no surfactant. However, in presence of CTAB micelles, the linear relationship between log k ψ and f( ε) was quite different from that in the other two cases. These results show that a macroscopic property such as the dielectric constant of the medium may be used to describe the effect of DMSO on the hydrolysis rates either in absence of surfactant or when this is dissolved as the monomer, but not in the presence of micellized surfactant.

Long chain ß-aminoethanols as micellar catalysts for the hydrolysis of diphenyl-<i>p</i>-nitrophenyl phosphate. The observation of an unusual enhancement of catalysis in the presence of added polyols

The hydrolysis of p-nitrophenyldiphenyl phosphate (PNPDPP, 7) catalyzed by N-dodecylaminoethanol (6a), N-tetradecylaminoethanol (6b), N-methyl-N-tetradecylaminoethanol (6c), and N-hexadecylaminoethanol (6d) was investigated at 25°C at various pH values in aqueous media containing additives. Added ethanol or dimethoxyethane produces very little activity of 6a, b, c toward 7. The highest activities of 6a, b were found at pH 8.0 and 8.5 in solvents containing 20% glycerol or ethylene glycol. Under no conditions was N-hexadecylaminoethanol (6d) found to be active. The kinetics of the reaction of 6b with 7 were also investigated in a medium containing various amounts of glycerol, polyethylene glycol 400 (PEG 400), and water at pH 7.6-8.5. The best catalytic system comprised 3 mM 6b in 20% aqueous ethylene glycol, pH 8.5, which accelerated the hydrolysis of 7 by 1700-fold over the blank rate. Kinetic experiments conducted using [7]/[6b] = 1 and 2 demonstrate that 6b exhibits true turnover catalysis. A mechanism for the catalyzed reaction is proposed.Key words: ß-aminoethanols, hydrolysis, p-nitrophenyldiphenyl phosphate, micelles, polyhydroxy alcohols.

A Quantitative Treatment of Dephosphorylation by an Amphiphilic Hydroxamate Ion. The Role of Micellar Charge

Comicelles of (Z)-dodecano-N-phenylhydroxamate ion (1b) with cationic and sulfobetaine surfactants effectively accelerate the hydrolysis of p-nitrophenyl diphenyl phosphate (pNPDPP). The surfactants are cetyl trimethyl- and tributylammonium bromide (CTABr and CTBABr respectively), and (tetradecyldimethylammonio)propanesulfonate (SB3-14). Reaction is slower in comicelles with Brij-35, 23-dodecyl ether (C12E23), and much slower in comicelles with sodium dodecyl sulfate (SDS). In all conditions, the hydroxamic acid was fully deprotonated and pNPDPP was fully micellar-bound and, on the basis of NMR data (Langmuir 1997, 13, 6439), it appears that the rate effects are due to differences in the relative locations of pNPDPP and the hydroxamate residue in the interfacial region, which are related to micellar charge. Inhibition of reaction in SB3-14 on addition of ClO4-, and acceleration in SDS by weakly hydrophilic cations, are understandable in these terms, as are effects of n-dodecyldimethylphosphine oxide and n...

Effects of copper(II) mixed micelles on autooxidation of 3,5-di- tert-butylcatechol and hydrolysis of p-nitrophenyl diphenyl phosphate

The rates of autooxidation of 3,5-di- tert-butylcatechol and hydrolysis of p-nitrophenyl diphenyl phosphate in various mixed micelles formed from copper(II) surfactants and sodium dodecyl sulphate, cetyltrimethylammonium bromide and octaethylene glycol monododecyl ether were measured under the condition which obeys the first-order kinetic law. When compared to the pure copper(II) surfactant alone, the autooxidation rate of 3,5-di- tert-butylcatechol was found to be significantly increased in mixed micellar medium where octaethylene glycol monododecyl ether is the co-surfactant. The other two co-surfactants have relatively smaller effects on the rates as compared to the neutral co-surfactant. In the hydrolysis of p-nitrophenyl diphenyl phosphate, other than a small increase in rate on addition of small amount of co-surfactant in some cases, the overall effect of the co-surfactant is to decrease the rate. Various reasons are presented to account for the observed rate effects.

Cu II—diamine complex catalyzed hydrolysis of phosphate triesters adsorbed on strong-base ion exchange resins. 31P NMR relaxation measurements

The Cu II—diamine complexes, (bipy)CuSO 4 and (tmen)CuSO 4, catalyze the hydrolysis of p-nitrophenyl diphenyl phosphate (PNDP) adsorbed on a strong-base ion exchange resin. Turnover is observed. The major hydrolysis products are diphenyl phosphate, p-nitrophenyl phenyl phosphate, and the ethanolysis product ethyl diphenyl phosphate (EDPP) which are observed in similar amounts in both the presence and absence of the Cu II—diamine catalysts. The apparent bimolecular rate constants found for the (bipy) CuSO 4 and (tmen)CuSO 4 catalysts are 0.023 and 0.024 M −1 s −1, respectively. CuSO 4 is inactive as a catalyst. 31P MAS NMR relaxation measurements of the stable EDPP product reveal that the Cu II—diamine complexes greatly enhance T 1 relaxation, whereas CuSO 4 has only minimal effect. These results are consistent with the complexation of neutral phosphorus esters by the Cu II—diamine catalysts. 31P T 1 measurements of hydrolytically-stable dimethyl methylphosphonate (DMMP) in water solutions of Cu 2+, (tmen)Cu 2+, and Mn 2+ suggest that DMMP exchanges rapidly between inner-sphere and outer-sphere complexes in a nearly identical manner with each of these paramagnetic species.

Reactivity of Organic Anions Promoted by a Quaternary Ammonium Ion Dendrimer

The catalytic activity of a dendritic polyether with quaternary ammonium terminal groups in the unimolecular decarboxylation of 6-nitrobenzisoxazole-3-carboxylate and bimolecular hydrolysis of p-nitrophenyl diphenyl phosphate catalyzed by o-iodosobenzoate ion is investigated

Acceleration of o-Iodosobenzoate-Catalyzed Hydrolysis of p-Nitrophenyl Diphenyl Phosphate by Cationic Polymer Colloids

Acceleration of o-Iodosobenzoate-Catalyzed Hydrolysis of p-Nitrophenyl Diphenyl Phosphate by Cationic Polymer Colloids

Catalysis of hydrolysis of p-nitrophenyl diphenyl phosphate by o-iodosobenzoate in cationic latexes and polyelectrolytes

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTCatalysis of hydrolysis of p-nitrophenyl diphenyl phosphate by o-iodosobenzoate in cationic latexes and polyelectrolytesWarren T. Ford and Hui YuCite this: Langmuir 1993, 9, 8, 1999–2007Publication Date (Print):August 1, 1993Publication History Published online1 May 2002Published inissue 1 August 1993https://doi.org/10.1021/la00032a018RIGHTS & PERMISSIONSArticle Views79Altmetric-Citations17LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (1 MB) Get e-Alerts Get e-Alerts

Anionic Effects on the Hydrolysis of p-Nitrophenyl Diphenyl Phosphate in Surface Active [Cu(R-tmed)X2] and [Cu(R-tmed)(acac)X] Complexes Where R-tmed = N,N,N′-Trimethyl-N′-alkylethylenediamine and X = Halide or Nitrate

The effects of the change of anion on the rate of hydrolysis of p -nitrophenyl diphenyl phosphate in [Cu(R-tmed)X2] and [Cu(R-tmed)(acac)X] micelles were studied at 25°C. It was found that the rate maxima of the bromide and nitrate complexes are lower than those of the chloride complexes. The effect is slightly more pronounced in the [Cu(R-tmed)X2] micelles. The pH-concentration profiles demonstrate the presence of the active copper(II)-OH species in the micelles and the kinetic results can be rationalized in terms of a multiple-equilibrium scheme which determines the concentration of the copper(II)-OH species under various conditions.

Studies on a new type of surface-active copper(II) complexes, acetylacetonatochloro( N,N,N′-trimethyl- N′-alkylethylenediamine) copper(II): An ESR, spectrophotometric, and kinetic investigation

Surface-active mixed copper (II) chelates of the type [Cu( R-tmed)(acac)Cl], where R = C 10H 21, C 12 H 25, and C 16H 33, were prepared and characterized by elemental analysis and IR spectroscopy. Critical micelle concentration value was obtained by surface tensiometry for each of the complexes. From the ESR and UV—visible spectrophotometric studies, a structure in which the square planar copper(II)-containing head groups position themselves in a face-to-face manner with the chloride ions/water molecules located between them is proposed. The observation of separate ESR signals for the monomers and micelle implies that the rate of exchange between them is slow on the ESR time scale, i.e., <1 × 10 8 s −1. The linewidth broadening on increasing the concentration and on addition of sodium chloride is caused by an increase in the size of the micelle. The micelles of these mixed copper(II) chelates exhibit good catalytic activities toward the hydrolysis of p-nitrophenyl diphenylphosphate. In general for a given chain length, however, the rate is roughly 10 times slower than that of [Cu( R-tmed)Cl 2]. The rate maximum in the rate vs concentration plot decreases as the chain length increases. This is attributed to a decrease in the degree of ionization of the micelle as the chain length increases.

Rapid hydrolysis of p-nitrophenyl diphenyl phosphate catalyzed by o-iodosobenzoate in cationic latexes

Rapid hydrolysis of p-nitrophenyl diphenyl phosphate catalyzed by o-iodosobenzoate in cationic latexes