Acetic acid/MIBK/water extraction

For the system water-acetic acid-MIBK in Fig. 15-11 the raffinate (water) layer is the solubility curve with low concentrations of MIBK, and the extract (MIBK) layer is the solubihty curve with high concentrations of MIBK. The dashed lines are tie lines which connect the two layers in equihbrium as given in Table 15-1. Example 2 describes the right-triangular method of calculating the number of theoretical stages required. 

Example 2 Stage and Composition Calculation A 100-kg/h feed stream containing 20 weight percent acetic acid in water is to he extracted with 200 kg/h of recycle MIBK that contains 0.1 percent acetic acid and 0.01 percent water. The aqueous raffinate is to he extracted down to 1 percent acetic acid. How many theoretical stages wiU he required and what will the extract composition he ... 

This result is very close to that obtained by using a McCabe-Thiele diagram (Fig. 15-23). From solubility data at Y = 0.1039 kg acetic acid/kg MIBK (given in Table 15-8), the extract layer contains 5.4/85.7 = 0.0630 kg water/kg MIBK, and Ye = (0.097)/( 1 -t- 0.097 -t- 0.063) = 0.084 mass fraction acetic acid in the extract. 

Sakai et al.measured degrees of extraction of acetic acid fim water using solvent mixtures composed of a secondary amine mixture, Amberiite LA-2 (Rohm Haas Corp.), with diluents such as hexane, CCI4, CHCI3, or methyl isobutyl ketone (MIBK). The ketone and CHCI3 diluents gave the highest values of Kd, consistent with the results for the extraction of acetic acid with tertiary amines. A weak effect of temperature on Kd was observed for LA-2 with CHCla diluent. Tertiary amines probably are better extractants because primary and secondary amines can react irreversibly when heated with acetic acid to form amides. 

Acetic acid is being extracted from water into methyl isobutyl ketone (MIBK) kao = 0.545. The values of kAw and kAo are, respectively, 0.678 and 2.03 in units of lbmol/(hr-ft -ACA) where ACa is measured in Ibmol/ft Calculate Kau, in units of cm/s. 

Ternary-phase equilibrium data can be tabulated as in Table 15-1 and then worked into an electronic spreadsheet as in Table 15-2 to be presented as a right-triangular diagram as shown in Fig. 15-7. The weight-fraction solute is on the horizontal axis and the weight-fraction extraction-solvent is on the vertical axis. The tie-lines connect the points that are in equilibrium. For low-solute concentrations the horizontal scale can be expanded. The water-acetic acid-methylisobutylketone ternary is a Type I system where only one of the binary pairs, water-MIBK, is immiscible. In a Type II system two of the binary pairs are immiscible, i.e. the solute is not totally miscible in one of the liquids. 

Single Stage and Cross Current Extraction of Acetic Acid from Methyliso utyl Ketone with Water The original mixture contains 35% acetic acid and 65% MIBK. It is charged at 100 kg/hr and extracted with water. 

Most of the ternary or pseudoternary wstems used in extraction are of two types one binary pair has hmited miscibility (termed a type 1 system), or two binary pairs have limited miscibility (a type 11 system). The water -h acetic acid -I- methyl isobutyl ketone (MIBK) system... 

A 200-lb/h process stream containing 20 wt % acetic acid (AA) in water is to be extracted with 400 Ib/h of methyl isobutyl ketone (MIBK) ternary containing 0.05 wt % acetic acid and 0.005 wt % water. Determine the number of theoretical stages required to achieve an acetic acid concentration of 1 wt % in the process stream. The equilibrium data for the MIBK and acetic acid system, for acetic acid weight ratios between 0.01 and 0.25, can be represented by... 

Dilevalol DBTA Salt to Dilevalol Hydrochloride. Very little improvement in the RR composition results from the transformation of dilevalol DBTA salt to dilevalol hydrochloride. Ethyl acetate was used as the solvent vehicle in early work. In a search for a more stable solvent methyl isobutyl ketone (MIBK) was selected as the best alternative. DBTA was removed by extraction into water with sodium hydroxide (DBTA of excellent quality was recovered from the aqueous phase in high yield >90%). The MIBK solution of dilevalol was then treated with hydrochloride acid to precipitate dilevalol hydrochloride (Scheme 9). The pH needed for maximum efficiency in the crystallization of dilevalol hydrochloride was 0.5 (this is in sharp contrast to the pH required for maximum efficiency in the crystallization of labetalol hydrochloride—pH 3.0). It should also be noted that dilevalol hydrochloride could not be handled in stainless steel equipment. Hastelloy, plastic or ceramic equipment was employed to eliminate the risk of coloration of dilevalol hydrochloride by traces of iron compounds. The plant equipment layout for this step is shown in Figure 5. 

---