Thermostatically Jacketed Glass CSTR Vessel
2.0 L vessel with internal overflow weir, 4 anti-swirl baffles, and 6-blade Rushton turbine.
Chemical & Process Engineering / CSTR Saponification Kinetics
FREE TO EXPLORELABORATORY 25 · CHEMICAL & PROCESS ENGINEERING
Continuous Stirred-Tank Reactor (CSTR) Saponification Kinetics & Space-Time Conversion
Operate a continuous stirred-tank reactor (CSTR) conducting the alkaline saponification of ethyl acetate with sodium hydroxide at steady state, monitor electrical conductivity to determine conversion X_A, and evaluate the second-order reaction rate constant k. 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.
SECOND-ORDER CSTR FACTOR X_A/(1 - X_A)^2—
PROCESS & PILOT PLANT TELEMETRY
Ready to sample with Space Time τ = 6.0 min.
Adjust Space Time τ, 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 (2.0 to 12.0 min). Evaluated using a 2.0 L jacketed glass CSTR with Rushton turbine at 400 RPM and 25.0 °C. Equimolar feed concentrations C_A0 = C_B0 = 0.050 mol/L. Linear regression relates X_A / (1 - X_A)^2 directly to space time τ to extract k = 5.6000 L/(mol·min).
Process apparatus & industrial sensors.
Dual Positive-Displacement Peristaltic Feed Pumps
Delivers equimolar 0.050 M NaOH and ethyl acetate feed streams at matched flow rates from 0.08 to 0.50 L/min.
Flow-Through Precision Conductivity Cell
Continuously measures reactor effluent conductivity with 0.01 mS/cm resolution to determine conversion.
Circulating Constant-Temperature Water Bath
Maintains reactor temperature constant at 25.00 ± 0.05 °C to eliminate Arrhenius temperature drift.
Digital Tachometer & Variable-Speed Impeller Drive
Maintains vigorous mixing at 400 ± 2 RPM to ensure ideal macro-mixing without vortex aeration.
Standardized Calibration Conductivity Solutions
Calibrates conductivity probe across 0% conversion (pure NaOH) and 100% conversion (sodium acetate).
FOLLOW THE METHOD
A reason behind every step.
Operate a continuous stirred-tank reactor (CSTR) conducting the alkaline saponification of ethyl acetate with sodium hydroxide at steady state, monitor electrical conductivity to determine conversion X_A, and evaluate the second-order reaction rate constant k. Standardized parameter settings: 2.0, 4.0, 6.0, 8.0, 10.0, 12.0 min.
01
Conductivity Sensor Calibration
Calibrate the conductivity cell using 0.050 M pure NaOH (representing 0% conversion, κ_0 ≈ 11.50 mS/cm) and 0.050 M pure sodium acetate (representing 100% conversion, κ_inf ≈ 3.80 mS/cm).
02
Thermal Conditioning & Priming
Circulate bath water through the reactor jacket at 25.0 °C; fill the reactor with 2.0 L of deionized water and turn on the Rushton impeller at 400 RPM.
03
Initial Flow Rate Setpoint
Set feed pumps to deliver 0.50 L/min each of 0.100 M NaOH and 0.100 M ethyl acetate (mixed feed C_A0 = 0.050 M, total flow v_0 = 1.00 L/min, space time τ = 2.0 min).
04
Steady-State Conversion Logging
Allow 3 residence times (6 minutes) for steady state; log effluent conductivity κ, and compute fractional conversion X_A = (κ_0 - κ) / (κ_0 - κ_inf).
05
Space Time Progression Protocol
Step total feed flow rate down through 0.50, 0.333, 0.250, 0.200, and 0.167 L/min to establish space times τ = 4.0, 6.0, 8.0, 10.0, and 12.0 min, recording steady conversion at each plateau.
06
Second-Order CSTR Kinetic Regression
Compute X_A / (1 - X_A)^2 for each run, plot versus space time τ, and fit a linear regression through the origin to determine rate constant k.
YOUR NOTEBOOK · 0 OBSERVATIONS
Turn measurements into chemical process engineering insight.
Points are your recorded observations. The solid regression line validates CSTR Saponification Kinetics mathematical scaling.
LINEAR REGRESSION FIT · y = mx + b
X_A / (1 - X_A)^2 = S · τ = 0.2800 · τ
| # | Reactor Space Time τ (min) | Second-Order CSTR Factor X_A/(1 - X_A)^2 (ratio) | Reactor space time τ (min) | CSTR second-order factor X_A / (1 - X_A)^2 | Remove |
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No readings yet. Execute a process trial and record it.
Calculate it yourself.
CHECK YOUR UNDERSTANDING
Explain what the process engineering metrics mean.
In an ideal Continuous Stirred-Tank Reactor (CSTR) at steady state, the concentration inside the reactor is:
For equimolar second-order reactants in an ideal CSTR, the design equation relating conversion X_A to space time τ is:
During the alkaline saponification of ethyl acetate, solution electrical conductivity:
To achieve 90% conversion of a second-order reaction, the required volume of a single CSTR compared to a PFR is:
THEORY AND UNIT OPERATIONS CONTEXT
Process engineering background & physical principles.
In chemical reaction engineering, continuous stirred-tank reactors (CSTRs or backmix reactors) are widely utilized for liquid-phase synthesis, polymerization, neutralization, and bioprocess fermentation. Operating under steady state with intense mechanical agitation, an ideal CSTR exhibits perfect spatial macro-mixing, meaning temperature, composition, and reaction rates throughout the reactor volume are uniform and identical to the exiting effluent stream. The benchmark model reaction in chemical engineering kinetics is the liquid-phase saponification of ethyl acetate with sodium hydroxide: CH3COOC2H5 + NaOH -> CH3COONa + C2H5OH. At equimolar feed concentrations (C_A0 = C_B0 = 0.050 mol/L), the reaction exhibits second-order irreversible kinetics: -r_A = k · C_A · C_B = k · C_A0^2 · (1 - X_A)^2. A steady-state species conservation balance over reactor volume V with total volumetric feed flow rate v_0 yields: V · (-r_A) = v_0 · C_A0 · X_A. Introducing the reactor space time τ = V / v_0 (the time required to process one reactor volume of feed) yields: k · C_A0 · τ = X_A / (1 - X_A)^2. Reaction progress is tracked in real-time by measuring solution electrical conductivity, which decreases as high-mobility hydroxide ions (OH-) are replaced by lower-mobility acetate ions (CH3COO-). In this laboratory investigation, an instrumented 2.0-liter glass CSTR is operated across space times from 2.0 to 12.0 min to measure conversion X_A and determine the kinetic slope S = k · C_A0 = 0.2800 min^-1 (k = 5.600 L/(mol·min)).
X_A / (1 - X_A)^2 = S · τ = 0.2800 · τ
Evaluated using a 2.0 L jacketed glass CSTR with Rushton turbine at 400 RPM and 25.0 °C. Equimolar feed concentrations C_A0 = C_B0 = 0.050 mol/L. Linear regression relates X_A / (1 - X_A)^2 directly to space time τ to extract k = 5.6000 L/(mol·min).