Multifunctional Hydrolytic Catalyses. IV. The Catalytic Hydrolysis of p-Nitrophenyl Acetate by Copolymers Containing Complementary Functional Groups (Hydroxamate and Imidazole)

Toyoki Kunitake, Yoshio Okahata

Research output: Contribution to journalArticle

27 Citations (Scopus)

Abstract

Water-soluble bifunctional polymers which contained N-phenylacrylohydroxamate unit and 4(5)-vinylimidazole unit were prepared, and the catalytic hydrolysis of p-nitrophenyl acetate was studied at 30°C in 28.9% EtOH-H2O. Under ordinary substrate concentrations (10-4-10-5M), the reaction followed the simple firstorder kinetics, indicating the complete turnover of the catalytic group. At higher substrate concentrations, the time course of the reaction was biphasic and the hydrolysis was shown to proceed mainly via the formation and the subsequent decomposition of the acetyl hydroxamate intermediate. The acylation rate at the hydroxamate anion unit was affected only insignificantly by the presence of the imidazole unit, and was much more efficient than those at the imidazole site. In contrast, the decomposition of the acetyl intermediate was remarkably accelerated (up to 103-fold) by the introduction of the imidazole unit. Thus, the appropriate combination of the nucleophilic functions of complementary nature led to much enhanced turnover rates of the catalytic site.

Original languageEnglish
Pages (from-to)15-22
Number of pages8
JournalMacromolecules
Volume9
Issue number1
DOIs
Publication statusPublished - Jan 1 1976

Fingerprint

Functional groups
Hydrolysis
Copolymers
Decomposition
Acylation
Substrates
Negative ions
Kinetics
Anions
Polymers
Water
4-nitrophenyl acetate
imidazole

All Science Journal Classification (ASJC) codes

  • Organic Chemistry
  • Polymers and Plastics
  • Inorganic Chemistry
  • Materials Chemistry

Cite this

Multifunctional Hydrolytic Catalyses. IV. The Catalytic Hydrolysis of p-Nitrophenyl Acetate by Copolymers Containing Complementary Functional Groups (Hydroxamate and Imidazole). / Kunitake, Toyoki; Okahata, Yoshio.

In: Macromolecules, Vol. 9, No. 1, 01.01.1976, p. 15-22.

Research output: Contribution to journalArticle

@article{1abcd2f142ad4004ad16bde52cc86179,
title = "Multifunctional Hydrolytic Catalyses. IV. The Catalytic Hydrolysis of p-Nitrophenyl Acetate by Copolymers Containing Complementary Functional Groups (Hydroxamate and Imidazole)",
abstract = "Water-soluble bifunctional polymers which contained N-phenylacrylohydroxamate unit and 4(5)-vinylimidazole unit were prepared, and the catalytic hydrolysis of p-nitrophenyl acetate was studied at 30°C in 28.9{\%} EtOH-H2O. Under ordinary substrate concentrations (10-4-10-5M), the reaction followed the simple firstorder kinetics, indicating the complete turnover of the catalytic group. At higher substrate concentrations, the time course of the reaction was biphasic and the hydrolysis was shown to proceed mainly via the formation and the subsequent decomposition of the acetyl hydroxamate intermediate. The acylation rate at the hydroxamate anion unit was affected only insignificantly by the presence of the imidazole unit, and was much more efficient than those at the imidazole site. In contrast, the decomposition of the acetyl intermediate was remarkably accelerated (up to 103-fold) by the introduction of the imidazole unit. Thus, the appropriate combination of the nucleophilic functions of complementary nature led to much enhanced turnover rates of the catalytic site.",
author = "Toyoki Kunitake and Yoshio Okahata",
year = "1976",
month = "1",
day = "1",
doi = "10.1021/ma60049a004",
language = "English",
volume = "9",
pages = "15--22",
journal = "Macromolecules",
issn = "0024-9297",
publisher = "American Chemical Society",
number = "1",

}

TY - JOUR

T1 - Multifunctional Hydrolytic Catalyses. IV. The Catalytic Hydrolysis of p-Nitrophenyl Acetate by Copolymers Containing Complementary Functional Groups (Hydroxamate and Imidazole)

AU - Kunitake, Toyoki

AU - Okahata, Yoshio

PY - 1976/1/1

Y1 - 1976/1/1

N2 - Water-soluble bifunctional polymers which contained N-phenylacrylohydroxamate unit and 4(5)-vinylimidazole unit were prepared, and the catalytic hydrolysis of p-nitrophenyl acetate was studied at 30°C in 28.9% EtOH-H2O. Under ordinary substrate concentrations (10-4-10-5M), the reaction followed the simple firstorder kinetics, indicating the complete turnover of the catalytic group. At higher substrate concentrations, the time course of the reaction was biphasic and the hydrolysis was shown to proceed mainly via the formation and the subsequent decomposition of the acetyl hydroxamate intermediate. The acylation rate at the hydroxamate anion unit was affected only insignificantly by the presence of the imidazole unit, and was much more efficient than those at the imidazole site. In contrast, the decomposition of the acetyl intermediate was remarkably accelerated (up to 103-fold) by the introduction of the imidazole unit. Thus, the appropriate combination of the nucleophilic functions of complementary nature led to much enhanced turnover rates of the catalytic site.

AB - Water-soluble bifunctional polymers which contained N-phenylacrylohydroxamate unit and 4(5)-vinylimidazole unit were prepared, and the catalytic hydrolysis of p-nitrophenyl acetate was studied at 30°C in 28.9% EtOH-H2O. Under ordinary substrate concentrations (10-4-10-5M), the reaction followed the simple firstorder kinetics, indicating the complete turnover of the catalytic group. At higher substrate concentrations, the time course of the reaction was biphasic and the hydrolysis was shown to proceed mainly via the formation and the subsequent decomposition of the acetyl hydroxamate intermediate. The acylation rate at the hydroxamate anion unit was affected only insignificantly by the presence of the imidazole unit, and was much more efficient than those at the imidazole site. In contrast, the decomposition of the acetyl intermediate was remarkably accelerated (up to 103-fold) by the introduction of the imidazole unit. Thus, the appropriate combination of the nucleophilic functions of complementary nature led to much enhanced turnover rates of the catalytic site.

UR - http://www.scopus.com/inward/record.url?scp=0343704277&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=0343704277&partnerID=8YFLogxK

U2 - 10.1021/ma60049a004

DO - 10.1021/ma60049a004

M3 - Article

VL - 9

SP - 15

EP - 22

JO - Macromolecules

JF - Macromolecules

SN - 0024-9297

IS - 1

ER -