Thermostated Liquid-Liquid Equilibrium Extraction Cell
500 mL jacketed Pyrex mixing cell equipped with Teflon bottom drain valve and magnetic stirrer.
Chemical & Process Engineering / Liquid–Liquid Extraction Equilibrium
FREE TO EXPLORELABORATORY 19 · CHEMICAL & PROCESS ENGINEERING
Liquid–Liquid Extraction Ternary Phase Equilibria & Distribution Coefficient K_D
Determine the binodal solubility curve and conjugate liquid–liquid tie lines for the ternary system water – acetic acid – ethyl acetate, evaluate the distribution coefficient K_D and selectivity β, and verify Nernst partition equilibrium. Explore interactive transport phenomena, unit operations simulation, and chemical engineering telemetry.
TRANSPORT PHENOMENA · UNIT OPERATIONS · PROCESS CONTROL · REACTION ENGINEERING
Your virtual chemical and process engineering laboratory.
EXTRACT ACETIC ACID CONC Y_A—
PROCESS & PILOT PLANT TELEMETRY
Ready to sample with Raffinate x_A = 15.0 wt%.
Adjust Raffinate x_A, then execute chemical process trial.
Chemical and process engineering telemetry is evaluated rigorously using 64-bit IEEE 754 precision. Residuals reflect ordinary least-squares regression across successive observations. Continuous data structures support high-fidelity transport phenomena and unit operations modeling.
Process engineering assumptions and boundary condition limits
The transport and thermodynamic models apply within the specified calibrated operating window (5.0 to 30.0 wt%). Evaluated using the ternary system water (carrier) – acetic acid (solute) – ethyl acetate (solvent) at 25.0 °C and 1.0 atm. Linear partition model relates extract mass fraction y_A directly to raffinate mass fraction x_A to extract K_D = 0.8850.
Process apparatus & industrial sensors.
Circulating Constant-Temperature Water Bath
Maintains equilibrium cell jacket temperature at exactly 25.00 ± 0.05 °C.
Automatic Digital Potentiometric Titrator
Titrates acetic acid in extract and raffinate phases with standardized 0.100 M NaOH with 0.01 mL resolution.
Precision Analytical Balance (0.1 mg resolution)
Gravimetrically prepares synthetic feed and solvent mixtures with 0.0001 g accuracy.
Abbe High-Precision Optical Refractometer
Measures refractive index n_D of conjugate phases to cross-verify ternary compositions.
Vortex Laboratory Mixer & Centrifuge
Accelerates phase disengagement and ensures complete liquid-liquid droplet separation.
FOLLOW THE METHOD
A reason behind every step.
Determine the binodal solubility curve and conjugate liquid–liquid tie lines for the ternary system water – acetic acid – ethyl acetate, evaluate the distribution coefficient K_D and selectivity β, and verify Nernst partition equilibrium. Standardized parameter settings: 5.0, 10.0, 15.0, 20.0, 25.0, 30.0 wt%.
01
Equilibrium Cell Thermostating
Set circulating water bath to 25.00 °C; circulate water through the equilibrium cell jacket for 15 minutes before charging chemicals.
02
Ternary Feed Preparation
Gravimetrically prepare a 200 g binary mixture of water and acetic acid containing 5.0 wt% solute; charge into the cell with 200 g of pure ethyl acetate.
03
Intense Agitation & Equilibration
Agitate the two-phase mixture vigorously with a magnetic stirrer at 600 RPM for 20 minutes to generate high interfacial contact area.
04
Phase Quiescence & Disengagement
Halt stirring and allow 30 minutes for complete gravitational phase separation into a clear bottom aqueous raffinate and clear top organic extract.
05
Conjugate Phase Sampling & Titration
Draw 5.0 mL of bottom raffinate and 5.0 mL of top extract; titrate each phase against standardized 0.100 M NaOH to determine acetic acid concentrations x_A and y_A.
06
Concentration Progression Protocol
Repeat procedure for initial aqueous feed concentrations yielding raffinate concentrations of 10.0, 15.0, 20.0, 25.0, and 30.0 wt% acetic acid.
07
Distribution Coefficient Regression
Plot extract concentration y_A versus raffinate concentration x_A, and fit a linear regression through the origin to evaluate K_D.
YOUR NOTEBOOK · 0 OBSERVATIONS
Turn measurements into chemical process engineering insight.
Points are your recorded observations. The solid regression line validates Liquid–Liquid Extraction Equilibrium mathematical scaling.
LINEAR REGRESSION FIT · y = mx + b
y_A = K_D · x_A = 0.8850 · x_A
| # | Raffinate Acetic Acid Conc x_A (wt%) | Extract Acetic Acid Conc y_A (wt%) | Raffinate phase concentration x_A (wt%) | Extract phase concentration y_A (wt%) | Remove |
|---|
No readings yet. Execute a process trial and record it.
Calculate it yourself.
CHECK YOUR UNDERSTANDING
Explain what the process engineering metrics mean.
The distribution coefficient K_D in liquid-liquid extraction is defined as:
A liquid-liquid extraction separation is thermodynamically feasible only if the selectivity β is:
On a triangular ternary phase diagram, the plait point represents:
In the water – acetic acid – ethyl acetate system, the organic extract phase floats on top of the aqueous raffinate because:
THEORY AND UNIT OPERATIONS CONTEXT
Process engineering background & physical principles.
Liquid–liquid extraction (solvent extraction) is a key chemical engineering separation technology used when distillation is economically or thermodynamically impractical—such as separating close-boiling mixtures, recovering heat-sensitive bioproducts, breaking azeotropes, or purifying dilute specialty chemicals. In extraction, an immiscible or partially miscible liquid solvent (ethyl acetate) is mixed with a liquid feed mixture (water and acetic acid). Solute (acetic acid) distributes between the two liquid phases based on chemical potential and activity coefficient differences until thermodynamic phase equilibrium is achieved. The solute-rich solvent phase is termed the extract, and the remaining solute-depleted feed phase is termed the raffinate. Phase equilibria for ternary liquid systems are represented on equilateral or right-triangular coordinates featuring a binodal solubility curve that separates the single-phase homogeneous region from the two-phase immiscible envelope. Within the two-phase region, straight tie lines connect conjugate liquid phases in mutual thermodynamic equilibrium. According to Nernst's distribution law for dilute-to-moderate concentrations, the equilibrium distribution coefficient K_D = y_A / x_A (ratio of solute mass fraction in extract to raffinate) remains constant: y_A = K_D · x_A. In this laboratory investigation, ternary mixtures of water, acetic acid, and ethyl acetate are equilibrated in a jacketed separatory cell across raffinate concentrations from 5.0 to 30.0 wt% to construct tie lines, determine distribution coefficient K_D, and evaluate extraction selectivity β.
y_A = K_D · x_A = 0.8850 · x_A
Evaluated using the ternary system water (carrier) – acetic acid (solute) – ethyl acetate (solvent) at 25.0 °C and 1.0 atm. Linear partition model relates extract mass fraction y_A directly to raffinate mass fraction x_A to extract K_D = 0.8850.