2-Butyl acetate ions

Butyl acetate ions, 240t 2 -Fluoro-5-methyl-(3,L-arabinofluranosyluracil,... 

The reactivity of the encounter complexes between protonated and acetylated (R)-and (5)-2-butyl acetate, (CH3COOsBu) M+ (sBu = (/ )-, (5)-, or ( )-2-butyl M = H (n= 1,2) CH3CO (n = 1)), and (S, S,, S )-tri-sec-buty I borate has been measured by FT-ICR-MS. The relevant ion patterns are shown in Scheme 12.475 The kinetic data of Table 20 reveal some differences in both the overall reactivity of chiral (CH3COOsBu) M+ ions toward (iS, iS, S )-tri-sec-butylborate (kUtl, k M, and k5) and the relative extent of the competing addition/elimination (k and k4), proton transfer (k2), and ligand exchange (fc3) channels. They clearly indicate that (S,S,S) tri-sec-butylborate reacts more efficiently with the homochiral (5)-2-butyl acetate ions, than with the heterochiral (R)-2-butyl acetate ones. As expected, the reaction efficiency of the racemate ( )-2-butyl acetate ions falls in between. 

A process to convert butenes to acetic acid has been developed by Farbenfabriken Bayer AG (137) and could be of particular interest to Europe and Japan where butylenes have only fuel value. In this process a butane—butylene stream from which butadiene and isobutylene have been removed reacts with acetic acid in the presence of acid ion-exchange resin at 100—120°C and 1500—2000 kPa (about 15—20 atm) (see Acetic acid and its derivatives, acetic acid). Both butenes react to yield j -butyl acetate which is then oxidized at about 200°C and 6 MPa (about 60 atm) without catalyst to yield acetic acid. 

Acetic acid may also be produced by reacting a mixture of n-butenes with acetic acid over an ion exchange resin. The formed sec-butyl acetate is then oxidized to yield three moles of acetic acid ... 

Schugerl 115] has recently furnished a detail analysis of the reactive extraction of penicdlin-G and V and precursors like phenyl and phenoxy acetic acids. Thirty different amines have been studied for reactive extraction of penicillins 116] in various solvents such as butyl acetate, chloroform, di-isopropyl ether, kerosene, dioctyl ether, etc. Tertiary amines in n-butyl acetate were found to be advantageous because of their low reactivity with solvent but the distribution coefficients of their complexes are significantly lower than those of secondary amines. While using quaternary ammonium salts for ion-exchange extraction, re-extraction is difficult and very large amounts of anion (e.g.. Cl ) are needed to recover penicillins. The basic relationship for distribution coefficient and extraction kinetics have now been fairly developed for amine-penicillin systems. 

A quantitative assessment of the effects of head group bulk on, S k2 and E2 reactions in cationic micelles has been made.148 The kinetics of the acid-catalysed hydrolysis of methyl acetate in the presence of cationic, anionic, and non-ionic surfactants has been reported on.149 The alkaline hydrolysis of -butyl acetate with cetyltrimethylammonium bromide has also been investigated.150 The alkaline hydrolysis of aromatic and aliphatic ethyl esters in anionic and non-ionic surfactants has been studied.151 Specific salting-in effects that lead to striking substrate selectivity were observed for the hydrolysis of /j-nitrophenyl alkanoates (185 n = 2-16) catalysed by the 4-(dialkylamino)pyridine-fimctionalized polymer (186) in aqueous Tris buffer solution at pH 8 and 30 °C. The formation of a reactive catalyst-substrate complex, (185)-(186), seems to be promoted by the presence of tris(hydroxymethyl)methylammonium ion.152... 

The peaks at m/z 56 and 61 in the mass spectrum of butyl acetate (Fig. 3.85) can be explained by the above rearrangements. The mass spectrum of ethyl buta-noate, Fig. 3.86, shows two important peaks due to odd-electron ions at m/z 88 and 60, resulting from two successive McLafferty rearrangements. 

Several substitution reactions are catalyzed by iron ions (Galli Bunnett 1984). A detailed preparative study was recently reported on the ferrous ion-initiated SrnI reactions of haloarenes with the sodium enolates of tcri-butyl acetate, /V-accty I morpholine and a number of higher A-acylmorpholines. Smooth and rapid substitution occurs and good to excellent yields were obtained of arylacetic esters, arylacetamides, and arylalkyl amides. The... 

The reaction of sodium enolates of -butyl acetate, A-acetylmorpholine and derivatives with iodoarenes catalyzed by Fe+2 salts in liquid ammonia gives good yields of substitution products. Bromoarenes react more sluggishly and chloroarenes almost do not react173, p-Diiodobenzene and p-chloroiodobenzene reacted with A-acetylmorpholine enolate and Fe+2 ions to give the disubstitution product in 55% and 51% yields, respectively173. 

Now consider the reaction of acetate ion with rert-butyl chloride ... 

The fact that the rate law depends only on the concentration of tert-butyl chloride means that only tert-butyl chloride is present in the transition state that determines the rate of the reaction. There must be more than one step in the mechanism because the acetate ion must not be involved until after the step with this transition state. Because only one molecule pert-butyl chloride) is present in the step involving the transition state that determines the rate of the reaction, this step is said to be unimolecular. The reaction is therefore described as a unimolecular nucleophilic substitution reaction, or an SN1 reaction. 

The rates of all the various decomposition pathways of the molecular ion of n-butyl acetate have been investigated using a double-focussing mass spectrometer [743]. There appears, however, to have been either an error in the calculation of times or the calculations are simply imprecise. The times reported appear to be too short, perhaps by something like a factor of 3. This being so, the agreement between these incorrect times and decomposition times for related ions [520] would not be significant. 

The log (rate) vs. log (time) curves for the McLafferty rearrangement in the molecular ions of n-butyl acetate, 2-phenylethyl acetate, 2-phenyl-propyl acetate and 2-dimethylaminoethyl acetate have been found to be approximately parallel to each other and the rates at any time decreased significantly on going from n-butyl acetate to 2-phenylethyl acetate to... 

The oxidation of acetate by peroxodisulphate is much slower than that of formate. Glasstone and Hickling showed that the products, which include carbon dioxide, methane, ethane, and ethylene, are similar to those produced by the anodic oxidation of acetate ions (Kolbe electrolysis), and they inferred that the same organic radicals are formed as intermediates. Similar results are reported by Eberson et al. for the oxidations of ethyl terf.-butyl-malonate, tert.-butyl-cyanoacetate, and ferl.-butyl-malonamate ions. The oxidations of these ions and of acetate by peroxodisulphate are first order with respect to peroxodisulphate and zero order with respect to the substrate. Mechanisms involving hydroxyl radicals are excluded because the replacement of peroxodisulphate by Fenton s reagent leads to different products, so Eberson et al. infer that the initial attack on the substrate is by sulphate radical-ions. Sengar and Pandey report that the rate of the silver ion-catalysed oxidation of acetate is independent of the peroxodisulphate concentration. 

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