Tools · Calculation

Fractional Distillation Predictor

Predict which fractions you'd actually collect on your column. Antoine boiling points at the column pressure, Fenske analysis on adjacent pairs, azeotrope warnings from the database.

Load from a stored product — search by CAS, molecule, manufacturer or product name

Column setup

Pressure (mmHg) Target purity (0–1)

Column length 20 cm

5 cm50100150200 cm

Packing

1.7 theoretical plates available (20.0 cm / 12.0 cm·plate⁻¹).

Components

CAS or name	Percent

Boiling-point map

Each component plotted at its bp; vertical bands show predicted fraction cuts.

Predicted fractions at 760.0 mmHg

1 cut given your column setup.

Fraction 1 · 56.2–64.6 °C

~100.0%

67-64-1 50.0%

67-64-1 · C3H6O · bp 56.2 °C

Methanol 50.0%

67-56-1 · CH4O · bp 64.6 °C

Co-distilling: 67-64-1 / Methanol have α = 1.36 ⇒ 19.1 plates needed (1.7 available — not enough).

Pair analysis (Fenske)

Minimum plates needed for each adjacent pair to reach the target purity.

Lower / Upper	Δbp °C	α	N_min	Verdict
67-64-1 / Methanol	8.4	1.36	19.1	co-distill

Try a different separation method

Distillation will be slow or capped here; common alternatives listed below. Future tick: a dedicated /extraction tool that ranks all methods for any input mixture.

Close boiling points: 67-64-1 and Methanol (Δ = 8.4 °C)

Pairs with < 10 °C bp gap need a long column and very careful reflux ratio control. Consider: (1) liquid-liquid extraction if there's a polarity gap; (2) selective crystallisation if one component has a distinct mp; (3) reactive separation (e.g. acid-base if one component is ionisable).

Vapor pressure: NIST WebBook Antoine constants. Plate count from column length / packing HETP (Perry's 8e §14). Fenske N_min = 2·log[s/(1−s)] / log(α) at total reflux gives the lower bound on plates; reverse-mode planning factor (1.5×) follows the Gilliland correlation. Azeotrope data from CRC Handbook + Dortmund Data Bank.

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Pressure–Temperature Nomograph Find a compound's boiling point at any reduced pressure — compound-aware, not a generic nomograph. Vapor Pressure Calculator Estimate vapor pressure at any temperature from Antoine constants. Pressure Unit Converter Convert between mmHg, torr, mbar, atm, psi, and kPa. Molar Mass Calculator Molecular weight and percent composition from any chemical formula.