Propyl acetate, hydrolysis

An interesting modification of the catalytic action of the cation exchange resin was reported by Affrossman (7 7). The hydrrdytic activity of the resin which carries various amounts of Ag is given in F%. 3—1. The activity toward propyl acetate decreases in proportion to the incxease in Ag, vdiich implies that the hydrolysis is a... 

Fig. 3-1. Hydrolysis of allyl acetate ( ) and propyl acetate (o) by the ion exchange rerin which carries various amounts of Ag" ".

The hydrolysis of the ester with OH is called saponification. If the ester is hydrolyzed in a known amount of base (taken in excess), the amount of base, used up can be measured and used to give the saponification equivalent, the equivalent weight of the ester. N-propyl acetate has the structure... 

Write a balanced chemical equation using condensed structural formulas for (a) foe formation of propyl acetate from foe appropriate acid and alcohol (b) the saponification (base hydrolysis) of methyl benzoate. 

In the long continued fractionation with the plain still-head, a considerable amount of moisture was absorbed by the esters and some hydrolysis took place.. Before the fractionations were completed it was necessary to treat the propyl acetate with potassium carbonate- and the methyl acetate with phosphorus pentoxide, and the loss was thus increased. 

Ketonic hydrolysis with a mixture of sulphuric and acetic acids of the ethyl Mobutyryltsobutyrate 3uelds di-tso-propyl ketone ... 

Ketonic hydrolysis to di-iso-propyl ketone. Mix 15 g. of the ester with 30 ml. of glacial acetic acid, 10 ml. of water and 10 ml. of concentrated sulphuric acid, and reflux in a flask coimected by a ground glass joint... 

Reactions of 2,3-dioxo-l,2,3,5,6,7-hexahydropyrido[l,2,3-carboxylic acids and the homologous acetic and propionic acids, prepared by basic hydrolysis of the corresponding ester, with amines, 28% NH4OH, and hydroxylamine derivatives in the presence of l-ethyl-3-[3-(dimethylamino)propyl]carbodiimide and hydroxybenztria-zole <1995BML1527>, 1995BML1533>, and in the presence of NEt3 and A, A -bis(2-oxo-3-oxazolidinyl)phosphinic... 

The use of a lipophilic zinc(II) macrocycle complex, 1-hexadecyl-1,4,7,10-tetraazacyclododecane, to catalyze hydrolysis of lipophilic esters, both phosphate and carboxy (425), links this Section to the previous Section. Here, and in studies of the catalysis of hydrolysis of 4-nitrophenyl acetate by the Zn2+ and Co2+ complexes of tris(4,5-di-n-propyl-2 -imidazolyl)phosphine (426) and of a phosphate triester, a phos-phonate diester, and O-isopropyl methylfluorophosphonate (Sarin) by [Cu(A(A(A/,-trimethyl-A/,-tetradecylethylenediamine)l (427), various micellar effects have been brought into play. Catalysis of carboxylic ester hydrolysis is more effectively catalyzed by A"-methylimidazole-functionalized gold nanoparticles than by micellar catalysis (428). Other reports on mechanisms of metal-assisted carboxy ester hydrolyses deal with copper(II) (429), zinc(II) (430,431), and palladium(II) (432). 

N-Acylation of 2-methyl-5,6-dihydro-4/f-l,3-thiazine with cinnamoyl chloride in the presence of triethylamine furnishes ( )-l-(2-methylenetetrahydro-l,3-thiazin-3-yl)-3-arylprop-2-en-l-ones 122. These products undergo hydrolysis readily due to the j jA -ketene acetal-type bonds present in the molecules and are therefore not stable. Thus ( )-3-(3-(4-methoxyphenyl)acrylamido)propyl ethanethioate 123 is isolated in 92% yield from the corresponding thiazine after column chromatography on Si02 or AI2O3 <2001S135>. 

Ethyl 2-methylbutanoate, 2-methylbutyl acetate and hexyl acetate contribute most to the characteristic aroma of Fuji apples [49]. In Red Delicious apples, ethyl butanoate, ethyl 2-methylbutanoate, propyl 2-methylbutanoate and hexyl acetate contribute to the characteristic aroma as determined by Charm-Analysis and/or AEDA [50, 51]. In a comparative study of 40 apple cultivars, the highest odour potency or Charm value was found for -damascenone [52]. This compound usually occurs in a glycosidically bound form and is present primarily in processed products owing to hydrolysis of the glycoside bond after crushing fruit cells [53]. -Damascenone has a very low odour threshold with a sweet, fruity, perfumery odour and is not typical of apple aroma in gen-... 

Isopropyl-2-phenylcyclobutanol (29) was obtained by hydroboration-oxidation of 4-iso-propyl-l-phenylcyclobutene.38 In a synthetically useful procedure, hydrolysis of 1,2-bis(phenylsulfanyl)cyclobutene at room temperature in a solution of copper(IT) chloride and titanium(IV) chloride in acetic acid gave 2-(phenylsulfanyl)cyclobutanone (30) in 85% yield.39... 

This technique and these results have been extended in a very complete investigation by Yates and McClelland37. These authors have measured the rates of hydrolysis of eight representative acetate esters in 10-100% sulphuric acid some of their results are plotted in Fig. 1, (p. 74.) Yates and McClelland also measured the protonation behaviour of three of the esters in the same medium, by the spectrophotometric method (p. 70). They found that the basicities of the three esters, methyl, -propyl and isopropyl acetate, are closely similar, and that their protonation behaviour is described by the equation37... 

Until relatively recently no kinetic studies on the nitrosation of alcohols had been reported, presumably since the reactions are very rapid and require special techniques. Some kinetic measurements on the reverse reaction, the hydrolysis of alkyl nitrites have been reported here conventional kinetic methods were used. Early workers examined the reactions of the series methyl, ethyl, i-propyl and t-butyl nitrites in an acetic acid-acetate buffer and found a small increase in rate constant along the series (Skrabal et a ., 1939). Later Allen measured the rate constants for the hydrolysis of a number of alkyl nitrites in aqueous dioxan solvent for both acid- and base-catalysed reactions (Allen, 1954). The rate constants for the O-nitrosation of alcohols were determined indirectly by measurement of the overall equilibrium constant for the process, by noting the change in the rate constant for the nitrosation of phenol in the presence of added alcohols. These, combined with the known data for the reverse hydrolysis reaction, enabled the rate constants for the forward reaction to be obtained (Schmid and Riedl, 1967). The reactivity sequence MeOH > EtOH > i-PrOH > t-BuOH was deduced, and attributed to a steric effect. 

A convenient three-component coupling reaction of Meldrum s acid, acrolein, and thioacetic acid was described <1997TL5785> for the synthesis of 2-(l,2-dithiolan-3-yl)acetic acid 315 (Scheme 58). As shown, diacetylthiolated propyl Meldrum s acid 311 was refluxed in methanol affording ester acid dithioacetate 312, which without purification was transformed upon acid-catalyzed methanolysis into diester 313. The subsequent oxidation step led to ester 314 which afforded the final acid 315 by a hydrolysis-decarboxylation sequence. 

In contrast, the intermediately formed methylenecyclopropane 44 reacts with electron-rich alkenes to give cycloadducts, e.g. 45, with the bis(acceptor)methylenecyclopropane reacting as a heterodiene. This hetero-Diels-Alder reaction is also applicable to electron-rich alkynes, e.g. formation of 46. Thus, a solution of 3-acetoxy-5,5-dimethyl-2-(l-piperidinocyclo-propyl)cyclohexen-2-enone (47) and 1 equivalent of alkyne was reacted at 36°C for 4 hours. Alkyl-substituted alkynes, although applied in great excess, did not form any products. Depending on the substituents, further acidic hydrolysis opens up a method for the preparation of acetates or lactones. 

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