Acetic acid 2,4-dinitrophenyl ester

NSC 8659 ihi(2,4-dinitrophenyl)-acetic acid ethyl ester CA Index Name Benzeneacetic acid, a-(2,4-dinitrophenyl)-2,4-dinitro-, ethyl ester CAS Registry Number 5833-18-1 Merck Index Number Not listed Chemical Structure... 

Dinitrophenyl ester of A,yV-dimcthyldithiocarbamic add is reduced with iron powder in glacial acetic acid with the formation of 5-nitrobenzothiazolethione-2 [407, 408] (Scheme 2.108), which is extensively used in coordinating chemistry [594-597],... 

Other Names Acetic acid, w(2,4-dinitrophenyl)-, ethyl ester Ethyl w(2,4-dinitrophenyl)acetate ... 

This sensitivity to substitution of neutral hydrolysis means that the pH-independent reaction gradually becomes more important than the hydroxide reaction at the high pH end of the region, and becomes much more rapidly more important than acid-catalyzed hydrolysis at low pH. Thus from Fig. 13, the acid-catalyzed reaction can be seen to be significant for the hydrolysis of ethyl acetate between pH 4 and 5, and for phenyl acetate about pH 2 but for 2,4-dinitrophenyl acetate the acid-catalyzed reaction is not detectable at pH 1, and is presumably important only in relatively strong acid. It seems certain that this fast neutral hydrolysis is at any rate a partial explanation for the low efficiency of acid catalysis in the hydrolysis of very weakly basic esters, such as the trifluoroacetates and oxalates, in moderately concentrated acid (see p. 145). 

The kinetics of 2,4-dinitrophenyl-acetate hydrolysis catalyzed by polymers containing imidazole, carboxylic acid, oxidation groups and their complexes with surfactants, such as 1-cetylpyridinium chloride and cetylundecyldimethylammonium bromide, was determined by spectrophotometry [57]. Catalytic rate constants of the second-order-rate increase with a rise in the surfactant concentration until they reach a plateau at a polymer/surfactant ratio of 1 6. Anionic surfactant does not accelerate the polymer-catalyzed hydrolysis. The catalytic mechanism of a polymer/surfactant complex enables the penetration of the substrate into a pseudophase of a soluble complex. This leads to an increase of the ester concentration in the neighbourhood of a polymer imidazole fragment and accelerates the process. Such a pseudophase promotes the protonation of imidazole rings. 

It has to be pointed out that, with a few exceptions, the acceleration by polyelectrolytes was associated with decreases and Table IV gives the thermodynamic parameters for the aquation reactions of Co(NH3)5Br induced by Ag". Similar decreases in and AS were found for various reactions the Hg -induced aquation of Co(NH3)5Br , the SpjAr reaction of dinitrochlorobenzoic acid with OH [51], the hydrolysis of 2,4-dinitrophenyl phosphates [reaction (E)] [33], the outer-sphere electron-transfers between Co-complexes [Co(NH3)5N3, Co(NH3)5Br , Co(en)2Cl2 ] and Ru(NH3)6 or [8, 20] [en ethylenediamine], the polyvinyl-imidazole-accelerated solvolysis of p-nitrophenylacetate [52], the coupling reactions of dinitrofluorobenzene with aminoacids [53], dipeptides [53] and aniline [54], the lignin sulfonic acid-accelerated hydrolysis of methyl acetate [55], and the hydrolysis of nitrophenyl esters [37]. The opposite tendency (acceleration caused by increases... 

The imidazole-catalysed hydrolysis of polar substituted 2,4-dinitrophenyl acetates (21 X = Cl, OMe) has been investigated at different temperatures. The observed rates correspond to the bimolecular nucleophilic addition of the imidazole at the carboxylic carbon atom followed by a very fast hydrolysis of the (V-acetylimidazole in water. The influence of polar substituents in the acid moiety of the ester molecule on the hydrolysis reaction can be described by an electrostatic dipole-dipole interaction in the same way as the neutral hydrolysis of polar substituted ethyl acetates. By the use of both quantum and classical dynamics, a study of the neutral hydrolysis of 4-methoxyphenyl dichloroacetate (22) in water concluded that the rate-determining step is a proton transfer concerted with formation of a C-O bond. ... 

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