ETHYLHEXYL PALMITATE

The 2-ethylhexyl stearate is used as a bio-lubricant in various cosmetic products. The present study is focused on the biocatalyzed esterification of 2-ethylhexanol and stearic acid to form 2-ethylhexyl stearate catalyzed by Fermase CALB 10000 in the presence of ultrasound treatment. The maximum conversion (95.87%) was obtained at molar ratio of 2-ethylhexanol to stearic acid 2:1, enzyme amount of 2 % (w/w), power 80 W, duty cycle 50 % and temperature 50°C in comparatively short reaction time (3 h) in the presence of Fermase as a catalyst. At optimum conditions, it is observed that in the presence of ultrasound; the reaction time minimizes up to 4 h as compared to mechanical stirring method (7 h). The physiochemical properties for the 2-ethylhexyl palmitate were also evaluated.

Skin dryness is an omnipresent symptom in various types of skin disorders. Thereby, a large panel of skin care products is developed for therapeutic purposes. However, there is still a lack of non-invasive methods to determine the mechanisms of action of moisturizers at the molecular level. In the present study, confocal Raman spectroscopy coupled to classical least square analyses and ATR-FTIR were used to investigate the effect of different molecules on the stratum corneum (SC) hydration degree and barrier state. First, hygroscopic property was determined by analyzing samples at 90% RH; secondly, the water barrier function was evaluated after the dehydration process (4% RH). The molecules penetration kinetics across SC were also studied for 2 h. Using the present approach, glycerin and propylene glycol were found to be humectants; lanoline showed occlusive action, lactic acid has both humectant and barrier enhancer properties, and ethylhexyl palmitate and caprylic/capric acid triglyceride seemed to be emollients. These observations are in accordance with literature. The present method non-invasively characterizes the mechanism of action of tested molecules. This may improve knowledge of new molecules' structure-activity relationship and help make an effective therapeutic concept dealing with the various skin dysfunctions.

2-Ethylhexyl palmitate has been prepared in organic solvents catalyzed by an immobilized lipase QLM. Microwave irradiation was used to improve the enzyme activity and shorten the reaction time. The reaction conditions under microwave have been optimized. Compared with that of the free QLM under classical heating, the immobilized QLM under microwave exhibited higher enzyme activity and the conversion could achieve 99% in about 3.0 h. Furthermore, the immobilized QLM displayed excellent reusability under microwave irradiation.