Butanal → 2-Propyl-1,3-dioxane

This example illustrates the limitations of conventional synthesis methods. A 500 mL round bottom was charged with 191 g normal butyraldehyde, 101 g of 1,3-propanediol, and 4 drops 85% phosphoric acid. The round bottom was fitted with a Dean-Stark trap and condenser and the entire apparatus was placed into an electric heating mantle and brought to reflux. The aldehyde/water azeotrope condensed and separated into the trap. Heating was maintained until 24 mL of water had evolved (1 hr). The mixture was cooled and poured into a separatory funnel. The solution was washed twice with 50 mL of saturated sodium bicarbonate solution and once with 50 mL of distilled water. The organics were dried over MgSO4 and the residue distilled. A fraction collected at 150° C. was 99.6% acetal and had a mass of 95.7 g. This corresponds to a yield of 56%, lower than the yields reported in Table II.

1. customthe limitations of conventional synthesis methods
2. customThe round bottom was fitted with a Dean-Stark trap and condenser
3. temperatureto reflux
4. customcondensed
5. customseparated into the trap
6. temperatureHeating
7. temperaturewas maintained until 24 mL of water
8. custom(1 hr)
9. temperatureThe mixture was cooled
10. additionpoured into a separatory funnel
11. washThe solution was washed twice with 50 mL of saturated sodium bicarbonate solution and once with 50 mL of distilled water
12. dry with materialThe organics were dried over MgSO4
13. distillationthe residue distilled
14. customA fraction collected at 150° C.

ORD record

ord-b022e53e2f1d4ea08123e46f1a191afb

Source dataset

uspto-grants-2016_04

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US09315485B2