Ultrasound-Assisted, Base-Catalyzed, Homogeneous Reaction for Ferulic Acid Production from γ-Oryzanol

Table 1

The yields of ferulic acid from hydrolysis of γ-oryzanol by heterogeneous and homogeneous systems with assistance of ultrasonic irradiation.

Type of reaction	γ-oryzanol (mg/mL)	KO^1 ratio	Temp.^2 (°C)	Yield of ferulic acid (%)
				Heating method	US (20 kHz)^3		US (200 kHz)^4
					50 W	180 W	50 W	180 W
Homogeneous condition (ethyl acetate/H2O/cosolvent: ethanol)
Type A	6	8	75	37.3	—	—	—	—
	6	10	75	56.5	—	—	—	—
	6	16	75	81.4	—	—	—	—
	6	20	75	83.3	—	—	—	—
	6	20	60	62.3	65.8	94.0	63.1	63.8
	6	20	50	45.8	52.2	—	52.0	—
	6	20	40	25.2	42.1	—	33.7	—
	6	20	30	18.8	34.2	—	26.1	—
Homogeneous condition (ethyl acetate/methanol/cosolvent: ethanol)
Type B	6	8	75	0.7	—	—	—	—
	6	10	75	0.9	—	—	—	—
	6	16	75	1.1	—	—	—	—
	6	20	75	1.8	—	—	—	—
Heterogeneous condition (ethyl acetate/H2O)
Type C	6	10	75	8.9	—	—	—	—
	6	20	75	12.3	—	—	—	—

Initial concentration of γ-oryzanol in ethyl acetate. ¹Mass ratio of KOH/γ-oryzanol (wt/wt). ²Reaction temperature. Ultrasound-assisted method with 20 kHz. ⁴Ultrasound-assisted method with 200 kHz. Reaction time: 180 min.