A phosphate-catalysed acyl transfer reaction. Hydrolysis of 4-nitrophenyl acetate in phosphate buffers

1984 ◽  
Vol 37 (12) ◽  
pp. 2559 ◽  
Author(s):  
CJ O'Conner ◽  
RG Wallace
Keyword(s):  
Transfer Reaction ◽  
Acyl Transfer ◽  
Acetyl Phosphate ◽  
Linear Rate ◽  
First Order ◽  
Buffer Solutions ◽  
Phosphate Species ◽  
Pseudo First Order ◽  
Acyl Transfer Reaction ◽  
Hydrolysis Of

The pseudo-first-order rate constants for the phosphate-catalysed hydrolysis of 4-nitrophenyl acetate have been determined in water at 310.5 K. The reaction has been followed spectrophotometrically by the disappearance of the ester and with n.m.r, spectroscopy by the appearance of both acetyl phosphate and the acetate ion and by the disappearance of ester. A phosphate-catalysed acyl transfer mechanism has been identified, in which the aryl ester is attacked by phosphate to give acetyl phosphate which is subsequently hydrolysed by water to acetate ion and regenerated catalyst. At concentrations of total phosphate exceeding 1.0 mol dm-3 the presence of dimeric phosphate species causes the appearance of a non-linear rate-concentration profile. Catalysis has been also been observed in 2,2'-(propane-1,3-diyldiimino)bis(propane-1,3-diol) buffer solutions.

Acid-catalyzed Solvolysis of Isonitriles. I

1971 ◽  
Vol 49 (14) ◽  
pp. 2455-2459 ◽  
Author(s):  
Y. Y. Lim ◽  
A. R. Stein
Keyword(s):  
Formic Acid ◽  
Acid Catalysis ◽  
Hydrolysis Product ◽  
Rate Dependence ◽  
Linear Rate ◽  
First Order ◽  
Methyl Amine ◽  
Acid Catalyzed ◽  
Pseudo First Order ◽  
Hydrolysis Of

The acid-catalyzed hydrolysis of methyl isonitrile has been examined. The initial hydrolysis product is N-methylformamide which is further hydrolyzed to methyl amine and formic acid at a much slower rate. The hydrolysis to N-methylformamide is pseudo-first order in methyl isonitrile and shows a linear rate dependence on concentration of general (buffer) acid at fixed pH. The significance of general acid-catalysis in terms of the mechanism of the hydrolysis is considered and taken as evidence for carbon protonation rather than nitrogen protonation as the initiating step.

scholarly journals MW irradiation and ionic liquids as green tools in hydrolyses and alcoholyses

2020 ◽  
Vol 10 (1) ◽  
pp. 001-010 ◽  
Author(s):  
Nikoletta Harsági ◽  
Betti Szőllősi ◽  
Nóra Zsuzsa Kiss ◽  
György Keglevich
Keyword(s):  
Ionic Liquids ◽  
Alkaline Hydrolysis ◽  
Alkyl Group ◽  
Phosphinic Acid ◽  
Reaction Times ◽  
Alternative Possibility ◽  
First Order ◽  
Pseudo First Order ◽  
Mw Irradiation ◽  
Hydrolysis Of

Abstract The optimized HCl-catalyzed hydrolysis of alkyl diphenylphosphinates is described. The reaction times and pseudo-first-order rate constants suggested the iPr > Me > Et ∼ Pr ∼ Bu order of reactivity in respect of the alkyl group of the phosphinates. The MW-assisted p-toluenesulfonic acid (PTSA)-catalyzed variation means a better alternative possibility due to the shorter reaction times, and the alkaline hydrolysis is another option. The transesterification of alkyl diphenylphosphinates took place only in the presence of suitable ionic liquids, such as butyl-methylimidazolium hexafluorophosphorate ([bmim][PF6]) and butyl-methylimidazolium tetrafluoroborate ([bmim][BF4]). The application of ethyl-methylimidazolium hydrosulfate ([emim][HSO4]) and butyl-methylimidazolium chloride ([bmim][Cl]) was not too efficient, as the formation of the ester was accompanied by the fission of the O–C bond resulting in the formation of Ph2P(O)OH. This surprising transformation may be utilized in the phosphinate → phosphinic acid conversion.

A kinetic standard for precise calibration of spectrophotometer cell temperature.

1981 ◽  
Vol 27 (5) ◽  
pp. 753-755 ◽  
Author(s):  
P A Adams ◽  
M C Berman
Keyword(s):  
Temperature Dependence ◽  
Rate Constants ◽  
Cell Temperature ◽  
First Order ◽  
Order Rate ◽  
Acid Catalyzed ◽  
Pseudo First Order ◽  
Hydrolysis Of

Abstract We describe a simple, highly reproducible kinetic technique for precisely measuring temperature in spectrophotometric systems having reaction cells that are inaccessible to conventional temperature probes. The method is based on the temperature dependence of pseudo-first-order rate constants for the acid-catalyzed hydrolysis of N-o-tolyl-D-glucosylamine. Temperatures of reaction cuvette contents are measured with a precision of +/- 0.05 degrees C (1 SD).

Organocatalytic Asymmetric Domino Michael/Acyl Transfer Reaction between γ/δ-Hydroxyenones and α-Nitroketones

2018 ◽  
Vol 83 (9) ◽  
pp. 5301-5312 ◽  
Author(s):  
Keshab Mondal ◽  
Subhas Chandra Pan
Keyword(s):  
Transfer Reaction ◽  
Acyl Transfer ◽  
Acyl Transfer Reaction

Organocatalytic asymmetric Michael/hemiketalization/acyl transfer reaction of 1,3-propanediones with (E)-2-(2-nitrovinyl)phenols

2019 ◽  
Vol 17 (7) ◽  
pp. 1718-1721 ◽  
Author(s):  
Nimisha Bania ◽  
Subhas Chandra Pan
Keyword(s):  
Transfer Reaction ◽  
Acyl Transfer ◽  
Keto Ester ◽  
Acyl Transfer Reaction

An organocatalytic asymmetric cascade Michael/hemiketalization/acyl transfer reaction between (E)-2-(2-nitrovinyl)phenols and 1,3-propanediones is disclosed to generate products having keto, ester and nitro functionalities.

Evidence for the formation of lignin-hexenuronic acid-xylan complexes during modified kraft pulping processes

Holzforschung ◽  
2006 ◽  
Vol 60 (2) ◽  
pp. 137-142 ◽  
Author(s):  
Zhi-Hua Jiang ◽  
Jean Bouchard ◽  
Richard Berry
Keyword(s):  
Acid Hydrolysis ◽  
Kraft Pulp ◽  
Kraft Pulping ◽  
Order Kinetic ◽  
Kraft Pulps ◽  
First Order ◽  
Pseudo First Order ◽  
Hexenuronic Acid ◽  
Kinetics Of ◽  
Hydrolysis Of

Abstract The finding that hexenuronic acid (HexA) groups can be selectively removed from kraft pulps by acid hydrolysis has provided an opportunity to reduce bleaching chemicals. However, there is evidence that the acid hydrolysis is not uniform. In this report, we evaluate the kinetics of acid hydrolysis of HexA in a xylan sample enriched with HexA, a conventional kraft pulp, and three modified kraft pulps: anthraquinone pulp (Kraft-AQ), polysulfide pulp (PS), and polysulfide-anthraquinone pulp (PS-AQ). We found that HexA present in the xylan and conventional kraft pulp behaved similarly toward the acid hydrolysis throughout. On the other hand, HexA present in the Kraft-AQ, PS-AQ and PS pulps was heterogeneous toward acid hydrolysis and the reaction can be separated into two pseudo-first-order kinetic phases, each of which has a different rate constant. The kinetic data provide evidence for the formation of lignin-HexA-xylan complexes during modified kraft pulping processes.

Identification of Molecular Crystals Capable of Undergoing an Acyl-Transfer Reaction Based on Intermolecular Interactions in the Crystal Lattice

2013 ◽  
Vol 19 (38) ◽  
pp. 12867-12874 ◽  
Author(s):  
Majid I. Tamboli ◽  
Shobhana Krishnaswamy ◽  
Rajesh G. Gonnade ◽  
Mysore S. Shashidhar
Keyword(s):  
Crystal Lattice ◽  
Intermolecular Interactions ◽  
Transfer Reaction ◽  
Molecular Crystals ◽  
Acyl Transfer ◽  
Acyl Transfer Reaction

Synthesis of strained cyclic peptides via an aza-Michael–acyl-transfer reaction cascade

2012 ◽  
Vol 48 (65) ◽  
pp. 8084 ◽  
Author(s):  
Jochem P. A. Rutters ◽  
Yvette Verdonk ◽  
Remko de Vries ◽  
Steen Ingemann ◽  
Henk Hiemstra ◽  
...  
Keyword(s):  
Cyclic Peptides ◽  
Transfer Reaction ◽  
Acyl Transfer ◽  
Acyl Transfer Reaction
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