Theoretical study on the reaction mechanism for the hydrolysis of esters and amides under acidic conditions

Hori, Kenzi; Ikenaga, Yutaka; Arata, K.; Takahashi, Takanori; Kasai, Kenji; Noguchi, Yuhei; Sumimoto, Michinori; Yamamoto, Hiroyuki

doi:10.1016/j.tet.2006.11.039

Cited by 55 publications

(44 citation statements)

References 17 publications

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“…It is proposed that this observed, unexpected behavior in ethanol–water 80:20 can be ascribed to hydrophobic interactions established between the pendant groups of the POx and the ethanol molecules. In fact, efficient amide hydration is critical for the hydrolysis reaction, as the cooperative interaction of three water molecules with each amide group has been demonstrated, by molecular modeling, to be required for its acidic hydrolysis 33. In the current system, solvating ethanol molecules are believed to preferentially shield the hydrophobic PEtOx side chains obstructing the access of water molecules to the amide carbonyl group (Figure 3), thereby suppressing the hydrolysis rate.…”

Section: Resultsmentioning

confidence: 89%

Enhanced Selectivity for the Hydrolysis of Block Copoly(2‐oxazoline)s in Ethanol–Water Resulting in Linear Poly(ethylene imine) Copolymers

Kuringen

Rosa

Fijten

et al. 2012

Macromol. Rapid Commun.

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The ability of merging the properties of poly(2-oxazoline)s and poly(ethylene imine) is of high interest for various biomedical applications, including gene delivery, biosensors, and switchable surfaces and nanoparticles. In the present research, a methodology for the controlled and selective hydrolysis of (co)poly(2-oxazoline)s is developed in an ethanol-water solvent mixture, opening the path toward a wide range of block poly(2-oxazoline-co-ethylene imine) (POx-PEI) copolymers with tunable properties. The unexpected influence of the selected ethanol-water binary solvent mixture on the hydrolysis kinetics and selectivity is highlighted in the pursue of well-defined POx-PEI block copolymers.

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Section: Resultsmentioning

confidence: 89%

Enhanced Selectivity for the Hydrolysis of Block Copoly(2‐oxazoline)s in Ethanol–Water Resulting in Linear Poly(ethylene imine) Copolymers

Kuringen

Rosa

Fijten

et al. 2012

Macromol. Rapid Commun.

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“…The effect of pH was not investigated as it is generally known that esters hydrolyse in both acidic 36 and basic media. 37 The method optimized method was validated for reproducibility and repeatability using different spiking levels of the phthalates and extracted them a minimum of n = 15 (5 solutions over 3 days).…”

Section: Validation Of the Methods And Comparison Of Its Performance Wmentioning

confidence: 99%

Extraction and Pre-concentration of Phthalic Acid Esters from Aqueous Solutions using Agitation-assisted Dispersed Binary Solvents Microextraction

2017

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As the search for efficient, affordable and environmentally friendly extraction methods continues, miniaturized solvent techniques are receiving considerable attention due to their simplicity, efficiency and fast extraction rates. Herein we report application of a modified dispersive liquid-liquid microextraction through the introduction of a second extracting solvent in place of a disperser solvent leading to a much improved organic solvent recovery after the extraction of phthalic acid esters from aqueous solutions. The method employs a 75 µL binary mixture of ethylacetate and tetrachloromethane with a 3:1 ratio, extraction time of 20 seconds, and 10 % NaCl. The method demonstrates sufficient linearity (R 2 ³ 0.9866) and repeatability (%RSD £ 12.5, for n = 15) with the estimated LOD in the range (0.01-0.05 ng mL -1 ) using the S/N approach. The method demonstrated significant enrichment factors averaging about 2100 with headspace and about 3000 and increase of over 40 % without headspace, indicating the importance of reduced headspace volume in this approach, especially if the ionic strength is increased. However, the method yielded a significantly wide range of recoveries (65-115 %) when applied to the analysis of spiked soil samples when coupled to hot-water extraction. However, this may not be entirely attributable to the extraction approach but rather heat-induced hydrolysis during the hot-water dissolution, prior to the proposed organic extraction method. KEYWORDSDispersive liquid-liquid microextraction, binary solvents, phthalic acid esters, headspace volume, extracting solvent recovery.

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“…Experience suggests that the transesterification reaction should proceed via a tetrahedral intermediate, or transition state, formed when the carbonyl carbon is attacked by alkoxide [10,11]. The characteristics of transesterification have been previously considered in terms of activation energy considerations [12,13]. In this study, quantum data concerning the transition state is derived from calculations using the Gaussian software (Gaussian R 03W Ver.…”

Section: Computation Methodsmentioning

confidence: 99%

“…In this study, quantum data concerning the transition state is derived from calculations using the Gaussian software (Gaussian R 03W Ver. 6, Gaussian, Inc.) [12,13]. To simulate the mechanism of the transesterification reaction of PET, a two-stage procedure was adopted as follows.…”

Section: Computation Methodsmentioning

confidence: 99%

Theoretical study of the transesterification reaction of polyethylene terephthalate under basic conditions

Asakuma

Nakagawa

Maeda

et al. 2009

Polymer Degradation and Stability

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Theoretical study on the reaction mechanism for the hydrolysis of esters and amides under acidic conditions

Cited by 55 publications

References 17 publications

Enhanced Selectivity for the Hydrolysis of Block Copoly(2‐oxazoline)s in Ethanol–Water Resulting in Linear Poly(ethylene imine) Copolymers

Enhanced Selectivity for the Hydrolysis of Block Copoly(2‐oxazoline)s in Ethanol–Water Resulting in Linear Poly(ethylene imine) Copolymers

Extraction and Pre-concentration of Phthalic Acid Esters from Aqueous Solutions using Agitation-assisted Dispersed Binary Solvents Microextraction

Theoretical study of the transesterification reaction of polyethylene terephthalate under basic conditions

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