Synthesis of Carboxylic Acid by 2-Hexenal Oxidation Using Gold Catalysts Supported on MnO₂

Table 4

Effect of reaction time on the selectivity during the oxidation of 2-hexenal using 1% Au/MnO₂.

Reaction time	Selectivity%
	Dimer	2-Hexenoic acid
2 h	3.5	95.2
4 h	4.4	94.1
8 h	4.8	94.0
16 h	5.3	92.3
24 h	8.3	89.1

Reaction conditions: 4.23 g of 2-hexenal, 0.06 g of catalyst, 50°C, atmospheric pressure.
Dimer: 4,6-dipropyl-3,4,5,6-tetrahydropyran-2-one-5-carboxaldehyde.