An aroma compound, also known as odorant, aroma, fragrance, or flavor, is a chemical compound that has a smell or odor. A chemical compound has a smell or odor when it is sufficiently volatile to be transported to the olfactory system in the upper part of the nose.
Citral SyntheticeEthyl Maltol
More accurate scientific tests showed many of these substances to be benzene derivatives. After the concept of aromaticity had been extended in the middle of the 19th century to include first all benzene derivatives, Emil Erlenmeyer suggested using the word “aromatic” for all compounds having similar properties to benzene. The decisive criterion for him was that the compound should tend more towards substitution reactions than towards addition ones.
Based on the structure developed by Kekulé, Robinson in 1925 proposed the ring symbol for benzene: The π-electrons being delocalised, the benzene molecule is represented as lying between two bordering structures. This delocalisation of bonds at the same time determines the characteristic stability of the benzene molecule – which also distinguishes the other aromatics.
In today’s chemical industry, the BTX aromatics (benzene, toluene and xylene) – largely produced from petroleum – are especially important. Everyday, they help meet fundamental human needs, such as health, hygiene, housing and food; and they are also strong in areas as diverse as transport, high technology, sports, leisure – and even art restoration and crime detection!