Salicylaldehyde (SA) or 2-hydroxybenzaldehyde is an organic aldehyde compound with a free phenolic group (-OH) at the ortho position. It is a colorless to light yellow, oily liquid that exhibits an almond-like odor at higher concentrations. This aromatic compound is renowned for its pleasant fragrance and volatility, making it a popular ingredient in perfume production. Additionally, it is suitable for enhancing the taste of various food and beverage products due to its aromatic properties. It also exhibits fungicidal and larvicidal activities contributing to its versatile applications. It plays a significant role as a reagent in the synthesis of coumarin. Salicylaldehyde is naturally present in plants and in the secretion of leaf beetle larvae.
The objective of the thesis was the synthesis and olfactory evaluation of 2-alkoxybenzaldehydes and 2-acyloxybenzaldehydes. These are various lipophilic derivatives of salicylaldehyde with pleasant smells which could be utilized as fragrances in cosmetics. Esterification and etherification reactions were performed on the free hydroxyl group through nucleophilic substitution. The progress and success of the reactions were monitored using thin-layer chromatography. The raw products were purified through column chromatography. Subsequently, the pure products were analyzed using two spectroscopic techniques, nuclear magnetic resonance, and infrared spectroscopy, which confirmed the structure of the products.
This was followed by an olfactory evaluation of the compounds with an olfactory test, with which the volunteers evaluated the pleasantness of the smell, the strength of the smell, and what the smell reminded them of. Ethers derived from salicylaldehyde have a more pleasant smell compared to esters. Among all the samples, 2-formylphenyl acetate had the most prominent smell, which was also described as the most unpleasant.
Ethyl 4-(2-formylphenoxy) butanoate stood out with the most pleasant odor, which was described as sweet, floral, and strongly perfume-like.
|
