Production of fatty acid esters from stearic, oleic, and palmitic acids and short-chain alcohols (methanol, ethanol, propanol, and butanol) for the production of biodiesel was investigated in this work. A series of montmorillonite-based clays catalysts (KSF, KSF/0, KP10, and K10) were used as acidic catalysts. The influence of the specific surface area and the acidity of the catalysts on the esterification rate were investigated. The best catalytic activities were obtained with KSF/0 catalyst. The esterification reaction has been carried out efficiently in a semi-continuous reactor at 150°C temperature higher than the boiling points of water and alcohol. The reactor used enabled the continuous removal of water and esterification with hydrated alcohol (ethanol 95%) without affecting the original activity of the clay.
An effective procedure was developed to produce high‐value added phenolic compounds through the conversion of 2‐phenylethanol (2‐PhEt) by using acid‐activated clays KSF for the hydrogen peroxide. Owing to KSF's ability to catalyze a variety of complex oxidations, it was likely to convert 2‐PhEt to hydroxytyrosol (HTY) and tyrosol (TY) derivatives. The analyses of catalytic solution revealed that the optimum conditions, giving a higher concentration of oxidation products such as HTY, were as follows: 2‐PhEt concentration 10−2 mol/L, the hydrogen peroxide concentration 5.05 × 10−2 and 0.6 g L–1 of KSF clays . The yield during the conversion reaction into HTY was around 25%. All compounds in the reaction mixture were identified by mass spectrophotometry using a LC‐MS apparatus. HTY, TY, meta‐tyrosol and ortho‐tyrosol were the major compounds. The antioxidant activity was realized by 2,2‐diphenyl‐1‐picrylhydrazyl (DPPH) method. In fact, it is revealed that the strongest inhibition percentage (PI = 96) was detected with the increase in the concentration of HTY. The approach proposed in the present work presents an environment friendly method.
Acid-activated clays KSF and KSF/0 were successfully used in the hydrogen peroxide conversion of phenyl acetic acid to high-added phenolic compounds: p-hydroxyphenyl acetic acid and 3,4-dihydroxyphenyl acetic acid, endowed with a powerful antioxidant capacity. The catalytic conversion enhancement could be correlated to the total surface acidity and the high iron content of the catalysts KSF/0 and KSF, respectively. The synthetic route described here was conducted under mild conditions with very low degree of mineralization and without significant Fe ion leaching observations. The synthesis reaction is operationally simple and could find application for industrial purposes.
Monoglyceride MG has a wide function in the food industry,
in particular
as a natural emulsifier, pharmaceuticals, cosmetics, antioxidant,
and antibacterial. Therefore, the production of polyol ester from
esterification of acid (OA) and glycerol was investigated. The process
optimization was performed using a Box-Behnken design, examining the
effects of temperature, molar ratio, and catalyst amount. For predicting
the optimal point, a second-order polynomial model was fitted to correlate
the relationship between independent variables and response (% MG).
The effects of temperature (100, 150, and 200 °C); catalyst amount
(4, 10, and 16% w/w); and glycerol/oleic acid ratio (1:1, 1:2, and
1:3) were investigated and found to deeply affect the reaction outcome.
At the optimal reaction conditions: 200 °C, 0.2% w/w KSF, and
a glycerol/oleic acid ratio (3:1), more than 71.8% monoglycerides
with selectivity of 80% were obtained. Confirmation experiments were
performed to demonstrate the effectiveness of this approach, and the
characterization of monoglycerides was performed using high-performance
liquid chromatography (HPLC).
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