Azeotropes ethyl acetate/water

The polished product is passed to a distillation train (3) where a novel distillation arrangement allows the ethanol/ethyl acetate water azeotrope to be broken. Products from this distillation scheme are unreacted ethanol, which is recycled, and ethyl acetate product. 

Examples of the separation of heterogeneous azeotropes using such a process include n-butanol-water, ethyl acetate-water, and ethyl ether-water (Othmer, 1963). 

In a nonideal system such as ethyl acetate/water/ ethanol, for instance, there exists considerable complexity from a phase equilibrium point of view because of the presence of a liquid liquid-equilibrium (LLE) envelope, as well as the presence of three binary azeotropes and a single ternary azeotrope. Attempts have been made to... 

Fig. 4.10 RD lines (full lines) and isotherms (dashed lines) in the system ethanol + acetic acid + ethyl acetate + water at 1 bar. The reactive azeotrope and the temperature minimum do not...

Fig. 16.32 Ternary solubility diagram showing the temperature dependence of the phase behaviour of ethyl acetate/ water/ethanol, indicating that the ternary azeotrope is two phase at 20 °C and single phase at 70 °C.

Distillation of the product will be complicated by the existence of azeotropes between ethanol and ethyl acetate, water and ethanol, and water and ethyl acetate. And the acetic acid-water and acetone-water mixtures are famous for their tangent pinches. Rigorous distillation simulations with thermodynamics that accurately predict each of these azeotropes and pinches will be required to have confidence in the design. 

This high OR flowrate in the ethyl acetate system can actually be predicted by the inner molar balance envelope in Figure 9.2 with the ROM plot of the ethyl acetate system in Figure 9.3. Assuming ideal conditions, the column top-vapor composition should be at the ethyl acetate-water azeotrope, and the column bottom composition should be very close to the pure acetic acid comer in Figure 9.3. Since the feed composition is at 50 mol% acetic acid and 50 mol% water and the other inlet stream to the column for the inner molar balance envelope in Figure 9.2 is the OR (recall that no aqueous reflux is necessary for this system), the intersection of the two inlet and outlet molar balance lines can be used to estimate the OR flowrate. Since the intersection point is closer to the OR composition point, the OR flowrate is quite high. If the feed is much richer in acetic acid, the OR flowrate will be lower than the current case. 

The physical piopeities of ethyl chloiide aie hsted in Table 1. At 0°C, 100 g ethyl chloride dissolve 0.07 g water and 100 g water dissolve 0.447 g ethyl chloride. The solubihty of water in ethyl chloride increases sharply with temperature to 0.36 g/100 g at 50°C. Ethyl chloride dissolves many organic substances, such as fats, oils, resins, and waxes, and it is also a solvent for sulfur and phosphoms. It is miscible with methyl and ethyl alcohols, diethyl ether, ethyl acetate, methylene chloride, chloroform, carbon tetrachloride, and benzene. Butane, ethyl nitrite, and 2-methylbutane each have been reported to form a binary azeotrope with ethyl chloride, but the accuracy of this data is uncertain (1). 

Podebush Sequence forPthanol—Water Separation. When ethyl acetate is used as the entrainer to break the ethanol—water azeotrope the residue curve map is similar to the one shown in Figure 21d, ie, the ternary azeotrope is homogeneous. Otherwise the map is the same as for ethanol—water—benzene. In such... 

Esters of medium volatility are capable of removing the water formed by distillation. Examples are propyl, butyl, and amyl formates, ethyl, propyl, butyl, and amyl acetates, and the methyl and ethyl esters of propionic, butyric, and valeric acids. In some cases, ternary azeotropic mixtures of alcohol, ester, and water are formed. This group is capable of further subdivision with ethyl acetate, all of the ester is removed as a vapor mixture with alcohol and part of the water, while the balance of the water accumulates in the system. With butyl acetate, on the other hand, all of the water formed is removed overhead with part of the ester and alcohol, and the balance of the ester accumulates as a high boiler in the system. 

Volkov (1994) has given a state-of-the-art review on pervaporation. A number of industrial plants exist for dehydration of ethanol-water and (.vwpropanol-water azeotropes, dehydration of ethyl acetate, etc. There is considerable potential in removing dissolved water from benzene by pervaporation. The recovery of dis.solved organics like CH2CI2, CHCI3, CCI4, etc. from aqueous waste streams also lends itself for pervaporation and pilot plants already exist. 

Weichbrodt et reported on the use of focused open-vessel microwave-assisted extraction (EOV-MAE) for the determination of organochlorine pesticides in high-moisture samples such as fish. The results were comparable to those with closed-vessel microwave-assisted extraction (CV-MAE) and ASE. The main advantage of FOV-MAE is that the use of Hydromatrix is unnecessary as the solvent mixture of ethyl acetate and cyclohexane allows the removal of water from the sample matrix via azeotropic distillation. 

The concentration of acrylic acid by extraction with ethyl acetate is a rather different illustration of this technique. As shown in Figure 13.4, the dilute acrylic acid solution of concentration about 20 per cent is fed to the top of the extraction column 1, the ethyl acetate solvent being fed in at the base. The acetate containing the dissolved acrylic acid and water leaves from the top and is fed to the distillation column 2, where the acetate is removed as an azeotrope with water and the dry acrylic acid is recovered as product from the bottom. 

The catalytic esterification of ethanol and acetic acid to ethyl acetate and water has been taken as a representative example to emphasize the potential advantages of the application of membrane technology compared with conventional distillation [48], see Fig. 13.6. From the McCabe-Thiele diagram for the separation of ethanol-water mixtures it follows that pervaporation can reach high water selectivities at the azeotropic point in contrast to the distillation process. Considering the economic evaluation of membrane-assisted esterifications compared with the conventional distillation technique, a decrease of 75% in energy input and 50% lower investment and operation costs can be calculated. The characteristics of the membrane and the module design mainly determine the investment costs of membrane processes, whereas the operational costs are influenced by the hfetime of the membranes. 

A stirred solution of 13.0 g (100 mmol) of 5-oxohexanoic acid and 17.5 g of (1, S. 2.S )-2-amino-1-phcnyl-1,3-propanediol is heated under reflux in benzene for 16 h with azeotropic removal of water. The solution is concentrated and the residue is dissolved in 600 mL of diethyl ether. The solution is washed with sat. aq NH4C1, water, sat. aq Na2C03 and brine before drying over MgS04 and concentration in vacuo to give a colorless oil yield 24 g (96%) 84 14 2 mixture of isomers (the major isomers are diastereomers while the minor isomer is a regioisomer). Rccrystallization from ethyl acetate/hexane furnishes colorless needles yield 15.7g(60%) mp98-99°C [ ]D +13.3 (c = 1.1, ethanol). 

In the chemical processing industry, extraction is used when distillation is impractical or too costly. Extraction may be more practical than distillation when the relative volatilities of two components are close. In other cases, the components to be separated may be heat sensitive like antibiotics or relatively nonvolatile like mineral salts. When unfortunate azeotropes form, distillation may be ineffective. Several examples of cost-effective liquid-liquid extraction processes include the recovery of acetic acid from water using ethyl ether or ethyl acetate and the recovery of phenolics from water with butyl acetate. 

HC1, then crystd from dilute HC1 (charcoal) to remove benzenesulphonic acid. It has been crystd from EtOH/water. Dried in a vacuum desiccator over solid KOH and CaCl2. p-Toluenesulphonic acid can be dehydrated by azeotropic distn with benzene or by heating at 100° for 4h under water-pump vacuum. The anhydrous acid can be crystd from benzene, CHCI3, ethyl acetate, anhydrous MeOH, or from acetone by adding a large excess of benzene. It can be dried under vacuum at 50°. 

Ethyl Acetate. The production of ethyl acetate by continuous esterification is an excellent example of the use of azeotropic principles to obtain a high yield of ester (2). The acetic acid, concentrated sulfuric acid, and an excess of 95% ethyl alcohol are mixed in reaction tanks provided with agitators. After esterification equilibrium is reached in the mixture, it is pumped into a receiving tank and through a preheater into the upper section of a bubblecap plate column (Fig. 5). The temperature at the top of this column is maintained at ca 80°C and its vapor (alcohol with the ester formed and ca 10% water) is passed to a condenser. The first recovery column is operated with a top temperature of 70°C, producing a ternary azeotrope of 83% ester, 9% alcohol, and 8% water. The ternary mixture is fed to a static mixer where water is added in order to form two layers and allowed to separate in a decanter. The upper layer contains ca 93% ethyl acetate, 5% water, and 2% alcohol, and is sent to a second recovery or ester-drying column. The overhead from this column is 95—100% ethyl acetate which is sent to a cooler and then to a storage tank. This process also applies to methyl butyrate. 

Procedure for 1,3-dioxolane formation with ethyl acetoacetate by azeotropic removal of water.128a Ethyl acetoacetate (30 g, 0.23 mol), ethane-1,2-diol (16g, 0.248 mol), a crystal of toluene-p-sulphonic acid and benzene (50 ml) (CAUTION) were placed in a round-bottomed flask fitted with a Dean and Stark water separator (Fig. 2.31(a)) and a reflux condenser. The reaction mixture was heated until no more water collected. The product was fractionally distilled under reduced pressure to give the cyclic acetal (35 g, 87%), b.p. 99.5-101 °C/17-18 mmHg. 

Nitromethane shows the simplest residue curve map with one unstable curved separatrix dividing the triangle in two basic distillation regions. Methanol and acetonitrile give rise two binary azeotropic mixtures and three distillation regions that are bounded by two unstable curved separatrices. Water shows the most complicated residue curve maps, due to the presence of a ternary azeotrope and a miscibility gap with both the n-hexane and the ethyl acetate component. In all four cases, the heteroazeotrope (binary or ternary) has the lowest boiling temperature of the system. As it can be seen in Table 3, all entrainers except water provide the n-hexane-rich phase Zw as distillate product with a purity better than 0.91. Water is not a desirable entrainer because of the existence of ternary azeotrope whose n-hexane-rich phase has a water purity much lower (0.70). Considering in Table 3 the split... 

Ethyl acetate from ethanol/water 177 Azeotrope problem ... 

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