Ethyl acetate production

Ethyl dimethylacetoacetate reacts instantly at room temperature when treated with ethoxide ion to y- ield two products, ethyl acetate and ethyl 2-methylpropanoate. Propose a mechanism for this cleavage reaction. 

Of all the stoichiometric organic waste products — ethyl acetate and propionate (step 3), Me3SiOR (steps 4 and 7), ethanol (steps 6 and 7), vV-methylmorpholine (step 8), PhjPO (step 9), and ethylene glycol (step 10) — all but one were removed simply upon workup or evaporation. 

The process is characterized by low-operating temperatures and pressures, which allow all equipment to be constructed from either carbon steel or low-grade stainless steels. It allows ethyl acetate to be made without requiring acetic acid as a feed material. The process is appropriate for both synthetic ethanol and fermentation ethanol as the feed. The synthetic ethanol can be impure ethanol without significantly affecting the conversion or selectivity. The product ethyl acetate is greater than 99.95%. 

Variations of the above procedures are sometimes employed. /S-Keto esters may be obtained by alcoholysis of the intermediate diacyl esters by sodium methoxide in methanol, as in the preparation of methyl /3-oxocaprylate (88%). The starting /S-keto ester can be converted to the new /S-keto ester in a single step. Thus, in the synthesis of ethyl ben- > zoylacetate (55%)> ethyl acetoacetate and ethyl benzoate are converted directly to this keto ester by distilling the lower-boiling product, ethyl acetate, thereby forcing the reaction to completion. ... 

The product, ethyl acetate, is called an ester, so the reaction as a whole is known as an esterification reaction. By combining various amounts of acetic acid and ethanol, different amounts of products were obtained once the reaction came to equilibrium (it takes about an hour of boiling in the presence of HC1, which acts as a catalyst.)... 

Esters and carboxylic acids contain two oxygen atoms—one with a single bond to a carbon atom, and the other with a double bond to the same carbon atom (see figure on page 39). Many esters occur naturally, are good nonpolar solvents, and tend to be fragrant, for which purpose they are often used in household products. Ethyl acetate, for example, is the solvent often used in fingernail polish remover. 

Two important points to note are that a small molecule, water, is produced by the reaction. Also the product ethyl acetate is known as an ester. There are many examples of condensation reactions in organic chemistry and other products as well as esters are produced. For example, amides can be produced by reactions between organic acids and amines. 

After about 20 minutes, when the liquid should be dry, filter it through a small fluted filter-paper into a 100 ml. distilling-flask attached to a water-condenser. Add some fragments of unglazed porcelain to the ethyl acetate, fit a 100° thermometer to the flask, and place the latter on a cold water-bath, which is then brought to the boil. Some ether is always formed as a by-product with the ethyl acetate, and by these means is carefully distilled off as a... 

Add in turn benzyl chloride (8 3 g., 8 o ml.) and powdered thiourea (5 gm.) to 10 ml. of 95% ethanol in a 100 ml. flask fitted with a reflux condenser. Warm the mixture on the water-bath with gentle shaking until the reaction occurs and the effervescence subsides then boil the mixture under reflux for 30 minutes. Cool the clear solution in ice-water, filter off the crystalline deposit of the benzylthiouronium chloride at the pump, wash it with ice-cold ethyl acetate, and dry in a desiccator. Yield, 11-12 g., m.p. 170-174°. The white product is sufficiently pure for use as a reagent. It is very soluble in cold water and ethanol, but can be recrystallised by adding ethanol dropwise to a boiling suspension in ethyl acetate or acetone until a clear solution is just obtained, and then rapidly cooling. 

Dissolve 10 g. of chloro- 2,4-dinitrobenzenet in 50 ml. of dioxan in a 250 ml. conical flask. Dilute 8 ml. of hydrazine hydrate with an equal volume of water and add this slowly with shaking to the dioxan solution, keeping the temperature between zo " and 25°. Heat under reflux for 10 minutes to complete the reaction and then add 5 ml. of ethanol and heat again for 5 minutes. Cool and filter oflF the orange 2,4-dinitrophenylhydra-zine. Recrystallise the dry product from ethyl acetate m.p. 200° (decomp.). Yield, 7 g. 

Ethyl acetate. Various grades of ethyl acetate are marketed. The anhydrous comjjound, b.p. 76-77°, is of 99 per cent, purity, is inexpensive, and is suitable for most purposes. The 95-98 per cent, grade usually contains some water, ethyl alcohol and acetic acid, and may be ptuified in the following manner. A mixture of 1 litre of the commercial ethyl acetate, 100 ml. of acetic anhydride and 10 drops of concentrated sulphuric acid is refluxed for 4 hours and then fractionated. The distU-late is shaken with 20-30 g. of anhydrous potassium carbonate, filtered and redistilled. The final product has a purity of about 99-7% and boils at 77°/760 mm. 

Allow a mixture of 0-5 g. of the tertiary amine and 0-5 ml. of colourless methyl iodide to stand for 5 minutes. If reaction has not occurred, warm under reflux for 5 minutes on a water bath and then cool in ice water. The mixture will generally set solid if it does not, scratch the sides of the tube with a glass rod. RecrystaUise the solid product from absolute alcohol, ethyl acetate, acetone, glacial acetic acid or alcohol-ether. 

Place a solution of 10 -4 g. of benzalacetophenone, m.p. 57° (Section IV,130) in 75 ml. of pure ethyl acetate (Section 11,47,15) in the reaction bottle of the catalytic hydrogenation apparatus and add 0 2 g. of Adams platinum oxide catalyst (for full experimental details, see Section 111,150). Displace the air with hydrogen, and shake the mixture with hydrogen until 0 05 mol is absorbed (10-25 minutes). Filter oflF the platinum, and remove the ethyl acetate by distillation. RecrystaUise the residual benzylacetophenone from about 12 ml. of alcohol. The yield of pure product, m.p. 73°, is 9 g. 

The problem is more complicated when the ambident nucleophile. 2-aminothiazole, reacts with an ambident electrophilic center. Such an example is provided by the reaction between 2-amino-5-R-thiazole and ethoxycarbonyl isothiocyanate (144), which has been thoroughly studied by Nagano et al. (64, 78, 264) the various possibilities are summarized in Scheme 95. At 5°C, in ethyl acetate, the only observed products were 145a, 148. and 150. Product 148 must be heated to 180°C for 5 hr to give in low yield (25%) the thiazolo[3.2-a]-s-tnazine-2-thio-4-one (148a) (102). This establishes that attack 1-B is probably not possible at -5°C. When R = H the percentages of 145a. 148. and 150 are 29, 50, and 7%, respectively. These results show that ... 

Acetaldehyde, first used extensively during World War I as a starting material for making acetone [67-64-1] from acetic acid [64-19-7] is currendy an important intermediate in the production of acetic acid, acetic anhydride [108-24-7] ethyl acetate [141-78-6] peracetic acid [79-21 -0] pentaerythritol [115-77-5] chloral [302-17-0], glyoxal [107-22-2], aLkylamines, and pyridines. Commercial processes for acetaldehyde production include the oxidation or dehydrogenation of ethanol, the addition of water to acetylene, the partial oxidation of hydrocarbons, and the direct oxidation of ethylene [74-85-1]. In 1989, it was estimated that 28 companies having more than 98% of the wodd s 2.5 megaton per year plant capacity used the Wacker-Hoechst processes for the direct oxidation of ethylene. 

Other acetyl chloride preparations include the reaction of acetic acid and chlorinated ethylenes in the presence of ferric chloride [7705-08-0] (29) a combination of ben2yl chloride [100-44-7] and acetic acid at 85% yield (30) conversion of ethyUdene dichloride, in 91% yield (31) and decomposition of ethyl acetate [141-78-6] by the action of phosgene [75-44-5] producing also ethyl chloride [75-00-3] (32). The expense of raw material and capital cost of plant probably make this last route prohibitive. Chlorination of acetic acid to monochloroacetic acid [79-11-8] also generates acetyl chloride as a by-product (33). Because acetyl chloride is cosdy to recover, it is usually recycled to be converted into monochloroacetic acid. A salvage method in which the mixture of HCl and acetyl chloride is scmbbed with H2SO4 to form acetyl sulfate has been patented (33). 

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