Butyl acetate, hydrolysis

In situ product separation by distillation offers applications in esterification (e.g., for ethyl acetate), trans-esterification (e.g., for butyl acetate), hydrolysis (e.g., for ethylene glycol, isopropyl alcohol), metathesis (e.g., for methyl oleate), etherification (e.g., for MTBE, ETBE, TAME), and alkylation reactions (e.g., for cumene). 

Hydrolysis (or saponification) of n-butyl acetate. Boil 4-5 g. of n-butyl acetate (Section 111,95) with 50 ml. of 10 per cent, sodium hydroxide solution under reflux until the odour of the ester can no longer be detected (about 1 hour). Set the condenser for downward distiUation and coUect the first 10 ml. of distillate. Saturate it with potassium carbonate, aUow to stand for 5 minutes, and withdraw all the Uquid into a small pipette or dropper pipette. AUow the lower layer of carbonate solution to run slowly into a test-tube, and place the upper layer into a small test-tube or weighing bottle. Dry the alcohol with about one quarter of its buUr of anhydrous potassium carbonate. Remove the alcohol with a dropper pipette and divide it into two parts use one portion for the determination of the b.p. by the Siwoloboff method (Section 11,12) and convert the other portion into the 3 5-dinitrobenzoate (Section III, 27) and determine the m.p. 

In another approach, a glucose-derived titanium enolate is used in order to accomplish stereoselective aldol additions. Again the chiral information lies in the metallic portion of the enolate. Thus, the lithiated /m-butyl acetate is transmetalated with chloro(cyclopentadienyl)bis(l,2 5,6-di-0-isopropylidene- -D-glucofuranos-3-0-yl)titanium (see Section I.3.4.2.2.I. and 1.3.4.2.2.2.). The titanium enolate 5 is reacted in situ with aldehydes to provide, after hydrolysis, /i-hydroxy-carboxylic acids with 90 95% ee and the chiral auxiliary reagent can be recovered76. 

Countercurrent flow has advantages in product and thermodynamically limited reactions. Catalytic packings (see Figure 9. Id) are commonly used in that mode of operation in catalytic distillation. Esterification (methyl acetate, ethyl acetate, and butyl acetate), acetalization, etherification (MTBE), and ester hydrolysis (methyl acetate) were implemented on an industrial scale. 

Although the Lewis cell was introduced over 50 years ago, and has several drawbacks, it is still used widely to study liquid-liquid interfacial kinetics, due to its simplicity and the adaptable nature of the experimental setup. For example, it was used recently to study the hydrolysis kinetics of -butyl acetate in the presence of a phase transfer catalyst [21]. Modeling of the system involved solving mass balance equations for coupled mass transfer and reactions for all of the species involved. Further recent applications of modified Lewis cells have focused on stripping-extraction kinetics [22-24], uncatalyzed hydrolysis [25,26], and partitioning kinetics [27]. 

Plots of the left-hand side of these equations against X are curved, allowing easy distinction of an A2 mechanism. Excess acidity plots using equation (59) are shown for some ester hydrolyses in sulfuric acid at 25°C in Fig. 10, for 1-butyl acetate,29 and for methyl 2,6-dimethylbenzoate and methyl benzoate.41 The first ester (leftmost line in Fig. 10) clearly undergoes an A1 hydrolysis, specifically AAil 29 the parameters of the line are slope 1.552 + 0.027 intercept... 

Prior to the actual metathesis event, coupling of 13 and 28 via an ester linkage was required (Scheme 2.3). Two methods were employed in this connection. The first involved the aforementioned two-carbon expansion of aldehyde 28. Thus, condensation of 28 with Rathke anion (lithiated tert-butyl acetate) generated a mixture of dia-stereomeric alcohols the major product was shown to have the requisite 3S configuration. TBS protection of ester 29 and subsequent ester hydrolysis generated the desired add, 31, which could be further esterified with alcohol 13 in 78 % yield. 

A comparison of the kinetics of alkaline hydrolysis of methyl, isopropyl and butyl acetates in propan-2-ol-water and t-butanol-water has revealed that the observed effects correlate with solvent structure. ... 

A recent example of a chemical study showing how strain effects could be important in an enzymatic reaction, dealt with the hydrolysis of benzaldehyde di-t-butyl acetal [18] (Anderson and Fife, 1971b). As shown by a Stuart-Briegleb model, substantial ground-state strain is present which would be partially relieved in the... 

For the condensation with the properly derivatized lysine part (112) 3 -terf-butyl-1,5-di-Af-hydroxysuccinimidyl citrate (113) was used (Chart 10). It was prepared from 1,5-dimethyl citrate by reaction with ferf-butyl acetate, alkaline hydrolysis of the methyl ester and coupling with W-hydroxysuccinimide by DCCI (257). 

Facilitated transport of penicilHn-G in a SLM system using tetrabutyl ammonium hydrogen sulfate and various amines as carriers and dichloromethane, butyl acetate, etc., as the solvents has been reported [57,58]. Tertiary and secondary amines were found to be more efficient carriers in view of their easy accessibility for back extraction, the extraction being faciUtated by co-transport of a proton. The effects of flow rates, carrier concentrations, initial penicilHn-G concentration, and pH of feed and stripping phases on transport rate of penicillin-G was investigated. Under optimized pH conditions, i. e., extraction at pH 6.0-6.5 and re-extraction at pH 7.0, no decomposition of peniciUin-G occurred. The same SLM system has been applied for selective separation of penicilHn-G from a mixture containing phenyl acetic acid with a maximum separation factor of 1.8 under a liquid membrane diffusion controlled mechanism [59]. Tsikas et al. [60] studied the combined extraction of peniciUin-G and enzymatic hydrolysis of 6-aminopenicillanic acid (6-APA) in a hollow fiber carrier (Amberlite LA-2) mediated SLM system. 

Penicillin acylase (immobilized) Penicillin G hydrolysis in countercurrent system, in water (low pH, 4-5.6)/butyl acetate [73]... 

EFFECT OF SOLVENT ON THE ACID-CATALYZED HYDROLYSIS OF /-BUTYL ACETATE ... 

A more detailed investigation has been reported by Stimson et al,64. It was anticipated that the hydrolysis of /-butyl acetate in 60% aqueous dioxan at 100°C would involve both Aac2 and Aal1 mechanisms, since the rates of... 

FAILURE OF THE ARRHENIUS EQUATION FOR THE HYDROLYSIS OF l-BUTYL ACETATE IN AQUEOUS ACETONE (0.5-2.0 X 10 -M IN HC1)M... 

Activation parameters that have been measured for Aal1 reactions are generally consistent with a unimolecular rate-determining step. The volume of activation for the hydrolysis of f-butyl acetate in 0.01 M HCI at 60°C is zero, within experimental error70. No significant change in rate is observed from atmospheric pressure up to 2 kbar, although this increase in pressure almost doubles the rate of hydrolysis of ethyl acetate in 0.1 M HCI at 35°C. 

Bunnett s -parameter is — 1.2 for the hydrolysis of f-butyl acetate catalyzed by HCI50, and his more recent parameter, , is — 0.21, from the same data at 25°C51. In both cases the value falls in the region expected for a reaction not involving a molecule of water in the transition state. 

While this possibility cannot be ruled out, it is not sufficient to explain the behaviour of /-butyl acetate. The hydrolysis of this ester has been studied by many authors. Some recent results for aqueous sulphuric acid at 25°C ire available from Bunton et al.56, and these data are included in Fig. 6. The plot for this ester shows a very strongly negative slope, which can be shown to be in the region of— 9 to — 10 by a plot on expanded scales. This is ail aberration from the behaviour expected by Yates and McClelland, and could arise from a breakdown of their approximations in the case of this ester, or from a factor not allowed for by them. Since all the other acetate esters used seem to behave... 

Fig. 7. The dependence on ionic strength of the rate coefficients for hydrolysis of protonated f-butyl acetate in aqueous sulphuric acid.

Positive-Tone Photoresists. The ester, carbonate, and ketal acidolysis reactions which form the basis of most positive tone CA resists are thought to proceed under specific acid catalysis (62). In this mechanism, illustrated in Figure 22 for the hydrolysis of tert-butyl acetate (type A l) (63), the first step involves a rapid equilibrium where the proton is transferred between the photogenerated acid and the acid-labile protecting group ... 

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