Phosphoric Acid → Cyclopentanone, 2-(1-hydroxypentyl)-

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Reaction Conditions

Reaction Steps

Then, the aqueous layer and the distilled fraction of (a) were introduced into a 500-mL four-necked flask and then 51.1 g cyclopentanone (1.34 mol including a re-used cyclopentanone) and 0.87 g (0.0105 mol) 48% NaOH, including NaOH for converting phosphoric acid contained in the aqueous layer to trisodium phosphate, were added thereto. The mixture was cooled to 15° C. under stirring, and 50.0 g (0.58 mol) valeraldehyde was added dropwise at the same temperature over 5 hours. Thereafter, the mixture was stirred at the same temperature for 2 hours. After the reaction was finished, the mixture was neutralized with 0.84 g (0.009 mol) 105% condensed phosphoric acid and separated into two phases at 40° C. The pH of the aqueous layer was 5.5. The resulting organic layer was 171.2 g, and the aqueous layer was 4.33 g. The organic layer was analyzed in the same manner as in Example 1. The result indicated that the reaction mixture contained 83.5 g (0.490 mol) 2-(1-hydroxy-n-pentyl)cyclopentanone (yield 84.6%) and 2.28 g (0.015 mol) 2-pentylidene cyclopentanone. 61.7 g cyclopentanone and 8.5 g water could be recovered by distillation from the organic layer. The phosphoric acid contained in the aqueous layer, as determined by titration with NaOH for converting it into trisodium phosphate, was 0.028 mol.

Provenance & Evidence