Reaktion #161320

Reaktionsgleichung

Levulinic acid

1,3-propanediol

levulinic acid

→

3-hydroxypropyl 4-(3-hydroxypropoxy)pentanoate

Ausbeute 5.3%

Reaktionsbedingungen

Aufarbeitung

1. 1
   Sonstigepurged with nitrogen three times
2. 2
   Sonstigereacted with 1000 psi of hydrogen for 20 hrs
3. 3
   workup.DISTILLATION1,3-Propylene glycol is distilled off at 58-59° C./0.1 mm
4. 4
   Sonstigeto give 14.7 g of the crude product
5. 5
   SonstigeThe crude product (1.0 g) is chromatographed on silica gel

Vorschrift

Levulinic acid (11.6 g; 0.1 mol), 1,3-propanediol (67.6 g; 0.89 mol), and 2.32 g of 10% Pd/C from Aldrich (20 wt % relative to levulinic acid) are charged to a Parr reactor, purged with nitrogen three times, heated to 200° C. with stirring, and reacted with 1000 psi of hydrogen for 20 hrs. GC analysis reveals that the reaction is complete. 1,3-Propylene glycol is distilled off at 58-59° C./0.1 mm to give 14.7 g of the crude product containing 79% of the desired monomer. The crude product (1.0 g) is chromatographed on silica gel using hexane-ethyl acetate from 3:1 to 1:1 to isolate about 0.62 g of 3-hydroxypropyl 4-(3-hydroxypropoxy)pentanoate. 1H NMR (δ, ppm, CDCl3): 1.07 d (3H, CH3), 1.66-1.80 m (6H, CH2), 2.31 m (2H, CH2CO), 3.1 (broad, 2H, OH), 3.39 m (2H, CH2O), 3.57 m (5H, 2×CH2OH, CH), 4.11 m (2H, COOCH2). 13C NMR (δ, ppm, CDCl3): 19.69 (CH3); 30.67, 31.85, 31.88; 32.68 (CH2 groups); 59.02, 61.21, 61.70, 67.06 (CH2O groups), 74.97 (CH), 174.15 (COO). Mass spectrum: m/e 234 (M+).

Quelle