α-ізометиліонон
Alpha-isomethyl ionone, also known as α-cetone, is a synthetically made and naturally occurring organic compound. It is an isomer of methyl ionone and smells flowery, with a violet secondary note.
- Type
- Складник
- Olfactive family
- Квіткові
- Source
- synthetically made and naturally occurring
- Chemical class
- norsesquiterpenoid (ionone)
Запах
Докладно
Цікавий факт
A single-nucleotide polymorphism in the OR5A1 receptor changes how people perceive beta-ionone, a related ionone. Individuals who are homozygous AA are about 100 times less sensitive to it and, at higher concentrations, perceive a pungent sour or vinegar odor instead. Individuals with at least one G allele are sensitive to beta-ionone and perceive a pleasant floral scent. Beta-ionone is a significant contributor to the aroma of roses despite its relatively low concentration.
Отримання й хімія
Спосіб отримання
Alpha-isomethyl ionone is made by a cross-aldol condensation of citral with methyl ethyl ketone. A high temperature and strong alkali are used. The ratio between the n-form and iso-form is controlled to obtain methyl pseudo-ionone and allow ring formation to occur. The iso-form is then synthesized. The parent ionone is made from citral and acetone, with calcium oxide as a basic heterogeneous catalyst, in an aldol condensation followed by a rearrangement reaction. Under base catalysis the carbanion of acetone adds to the carbonyl group of citral. The aldol product loses water through the enolate ion to form pseudoionone. A double bond of pseudoionone then opens to form a carbocation, which rearranges with closure of the ring. Finally a hydrogen atom is removed by an acceptor molecule, giving one of two products, one of them with an extended conjugated system.
- Формула
- C₁₄H₂₂O
- CAS
- 127-51-5
- Зовнішній вигляд
- clear, colourless to yellowish liquid
- Синоніми
- α-cetone, cetone alpha, isomethyl-α-ionone, gamma-methylionone, α-isomethyl ionone
IFRA Standard « Methyl ionone, mixed isomers » covers CAS 127-51-5 (Amendment 49)
- Температура кипіння
- 238 °C
- Відносна густина
- 0.925-0.934
- Показник заломлення
- 1.498-1.503
У парфумерії
It is often used in flavouring and cosmetic industries, for example in aftershave lotions, bath products, hair care products, moisturizers, perfumes, shampoos and skin care products. It is used in perfume fragrances such as amber, chypre, violet, mimosa, reseda, iris, orris and cyclamen. Further fragrance types in which it appears include berries, woody notes, ylang-ylang, leather, orange, nut, pistachio, muscatel and tobacco. The share of alpha-isomethyl ionone in perfumes ranges approximately from 0.1% to 11.9%, with an average of 1.1%. It is usually used in conjunction with hydroxycitronellal, woody notes, copaiba, N-methyl ionone, ionone, or vetiver. It occurs in perfumes, toilet waters, aftershaves and various perfumed cosmetics. In cosmetic products its functions are fragrance and skin conditioning. Fragrance means that it enhances the smell of a product or perfumes the skin, and skin conditioning means that it maintains the skin in good condition. Fragrance compounds as a whole make up on average 15-30% of a perfume, 10-14% of an eau de parfum, 6-9% of an eau de toilette and 3-5% of an eau de cologne.
Див. також
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