Question

Fractional distillation of acetone & 1-propanol mixture. Please label which peak is acetone and which is 1-propanol for both pages. Thanks.
TCD1 B, Back Signal (220B2001.D) 25 V 1.528 1.613 2000 - 1500- 1000 - 500 > 1.455 0.5 min = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = Area Percent Report ========== Sorted By Signal Multiplier 1.0000 Dilution 1.0000 Do not use Multiplier & Dilution Factor with ISTDs Signal 1: TCD1 B, Back Signal ο Peak RetTime Type Width Area Height Area # [min] [min] [25 V*s] [25 V] ----I-------I---- ------- ---------- ---------- --------| 1 1.455 VV 0.0150 66.70992 59.85148 1.33578 2 1.528 VB S 0.0122 1989.12085 2264.98584 39.82952 3 1.613 BB T 0.0218 2938.25659 2165.58154 58.83471 Totals : 4994.08736 4490.41886

Answer 1

Acetone has boiling point of 56°C, which is significantly lower boiling point than of 1-propanol, whose boiling point is 97°C. Although both compounds are polar and take part in dipole-dipole intermolecular forces, 1-propanol also participates in hydrogen bonding due to its OH group, which is stronger than dipole-dipole attractions. Due to this, more energy is needed to break the intermolecular forces of 1-propanol compared to acetone, resulting in a higher boiling point.

Retention time of molecules depends on their boiling points :

• First signal spectra : retention time 1.528 min : Acetone ; retention time 1.613 min : 1-propanol
• 2ndsignal spectra : retention time 1.525 min : Acetone ; retention time 1.597 min : 1-propanol