Lilial
Lilial is a chemical compound commonly used as a perfume in cosmetic preparations and laundry powders, often under the name butylphenyl methylpropional. It is an aromatic aldehyde, naturally occurring in crow-dipper and tomato plants, and produced synthetically in large scale. It was banned for use in cosmetics by the EU in March 2022 after being found to be harmful to fertility.
It is also used as an intermediate in the synthesis of agrochemicals such as fenpropimorph and fenpropidin.
Synthesis
Lilial is produced by the mixed aldol coupling of 4-tert-butylbenzaldehyde and propionaldehyde, followed by hydrogenation.Properties
Lilial is commonly produced and sold as a racemic mixture; however, testing has indicated that the different enantiomers of the compound do not contribute equally to its odor. The -enantiomer has a strong floral odor, reminiscent of cyclamen or lily of the valley; whereas the -enantiomer possesses no strong odor.Like most aldehydes, lilial is not long term stable and tends to slowly oxidize on storage.
Safety
The Scientific Committee on Consumer Safety concluded in May 2019 that the use of lilial in both rinse-off and leave-on cosmetics "cannot be considered as safe".After animal studies found it to be toxic for reproduction, it was reclassified as a prohibited substance in the EU, and banned from use in cosmetics as of March 2022.
It can sometimes act as an allergen and may cause contact dermatitis in susceptible individuals. Lilial was used in many perfumes produced before 2022 as a synthetic substitute for the scent of lily of the valley. Due to the ban on the use of Lilial, safe analogues are currently used in perfume production.