SONOCHEMICAL SYNTHESIS OF ETHYL CINNAMATE

This research aimed to determine the yield of ethyl cinnamate synthesized by the sonochemical method and its potency as a sunscreen agent. Ethyl cinnamate was synthesized from cinnamic acid and ethanol with concentrated sulfuric acid as catalysts assisted by ultrasonic waves. The Identification of compounds was carried out by infrared spectrophotometry and gas chromatography-mass spectroscopy. Synthesis of ethyl cinnamate resulted in the form of clear yellow liquid with a fragrant aroma of a cinnamon ester with a 96.61% yield. Identification by an infrared spectrophotometer showed many functional groups of ethyl cinnamate. Identification by GC-MS was given a relative abundance of 98.96%. The product of synthesis had SPF number 4.769 at 10 ppm used Mansur Equation. Based on this research, it concluded that it has potential as a sunscreen agent. The sonochemical method provides an excellent yield of ethyl cinnamate.

production, synthesis of vitamin D and melanin pigment [1]. Overexposure of the ultraviolet radiation causing any damages in the skin like sunburns, hyperpigmentation, photo-aging and skin cancer [1,2]. Dermatologists recommended sunscreen with has higher SPF to minimize effects caused by UV radiation [3,4]. Sunscreens are used to protect against harmful UV radiation from the sun based on its ability to absorb, reflect or scatter the sun's rays [2].
Organic sunscreens protect the skin by absorbing the radiation, protecting against erythema and skin wrinkling, and reflect UV radiation [3]. Synthetic ethyl cinnamate is widely used in the food industry, especially for beverages and baked goods. Application of ethyl cinnamate in the cosmetic and pharmaceutical industry is also significant due to the characteristic flavor and fragrance, as well as high boiling point and stability [4].
Ethyl cinnamate can be used as flavor fixative agent in the perfume industry [4]. Ethyl cinnamate can be synthesized using different methods: esterification of corresponding cinnamic acids with alcohols, Wittig reaction, Reformatsky reaction, Heck reaction, as well as other methods [4].
Classical methods and microwave methods were used for synthesis of this compound in the industry [5]. Sonochemistry has been chosen for synthesis in the last years. A large number of many synthesis organic use of this technique. This technique is more convenient and easily controlled than traditional methods [10,11]. Synthesis organic using ultrasound irradiation offers reduction on-time reaction, simplicity of operation, cleaner reaction, easy and highly yields [6], eco-friendly because minimize waste and reduce energy [13,14,15].
Synthesis of ethyl cinnamate using the classical method is carried out for a long time [9], and synthesis of ethyl cinnamate using sonochemistry has never been done. Based

Material
Cinnamic acid was purchased from Sigma-Aldrich, ethanol from Mallinckrodt Chemicals, ether, sodium bicarbonate, magnesium sulphate, concentrated sulphuric acid was pro analysis.

Sunscreen activity of ethyl cinnamate
The ability of the product to protect UV light was assayed by spectrophotometer UV. The concentration of the product was made by 10 ppm and assayed at 290-320 nm with every 5 nm increment used spectrophotometer UV. The ability of sunscreen was expressed as Sun Protection Factor (SPF) and determined by Mansur equation [15,17]. The Sonochemical method could reduce their reaction time [9,11,17,18].  the molecules oscillate around their mean position [12]. When the intensity of ultrasound in a liquid was increased, the intramolecular forces were not able to hold the molecular structure intact and then it separated, and a cavity was formed [8]. The cavity caused physical and chemical effects for a molecule.

RESULTS AND DISCUSSION
The cavitation supplied energy for chemical reaction [9].   UV spectroscopy stimulates appreciation of why an ester cinnamate is chosen as a sunscreen component rather than the precursor cinnamic acid [16]. Ethyl cinnamate can absorb UVB radiation more effectively than cinnamic acid ( Figure 6) [10]. Ethyl cinnamate has a highly conjugated compound to absorb radiation at 290-320 nm wavelength [10]. Derivative of cinnamic acid is the best candidate to filter of UVB irradiation [3].