β-シトロネロール

外観

無色～わずかにうすい黄色, 澄明の液体

定義

本品は、次の化学式で表されるテルペンアルコールである。

溶解性

水に難溶, エタノール, アセトンに易溶。エタノール及びアセトンに極めて溶けやすく、水に極めて溶けにくい。

解説

シトロネロールは，鎖状モノテルペンアルコールの一つ。多くの植物精油中にα-とβ-の混合物として存在する。シトロネロールには1個の不斉炭素原子があるので、右旋性（d体）、左旋性（l体）および不活性（dl体、ラセミ体）の光学異性体がある。シトロネロールはシトロネラ油、ゼラニウム油に含有され、甘いバラ様の香気を有する無色の液体である。引火点102℃。シトロネラ油を精留してシトロネロール留分をとり、精製して製品とする。シトロネラールを接触水添しても得られる。バラ、ミューゲ、スズランなどのフローラル系調合香料に用いられる。［佐藤菊正］

解説

C10H20O(156.26)．β-シトロネロールは，非環状モノテルペンアルコール．多くの植物の精油中に含まれている．"ローズ油には(－)-シトロネロールが含まれ，シトロネラ油を還元すると(＋)-シトロネロールが得られる．(－)-シトロネロールはロジノール(rhodinol)ともよばれ，香料としては(＋)-シトロネロールよりすぐれている．(＋)-シトロネロールは沸点224.5 ℃，108.4 ℃(1.3 kPa)．d²⁰₄0.86．n²⁰_D1.46．[α]_D＋5.22°(クロロホルム)．[CAS 7540-51-4:(S)-(－)シトロネロール][CAS 106-22-9:ラセミ体] 森北出版「化学辞典（第2版）

用途

香料材料、有機合成原料。

化粧品の成分用途

香料

説明

Citronellol is a kind of natural occurring acyclic monoterpenoid which can be found in citronella oils such as Cymbopogon nardus ((+)-citronellol) and rose oils and Pelargonium geraniums ((-)-citronellol). In addition to be extracted from natural oils, it can also be manufactured by the hydrogenation of geraniol or nerol. It is mainly used in perfumes and insects repellents as well as being used as a mite attractant. It should be noted that it is an excellent mosquito repellent at short distances. Combination with beta-cyclodextrin can make it has an average duration time of 1.5 hour against the mosquitoes. It can also be used for the manufacture of rose oxide. One of its most common applications is for adding floral and citrus notes to perfumes, soaps and cosmetics.

化学的特性

Citronellol has a characteristic rose-like odor. Because odor plays such an important part in selecting this material, there may be special grades of citronellol that do not meet the Essential Oil Association specification. These limits have been broadened enough to include best qualities of commercial citronellol and chemically pure citronellol. l-Citronellol has a sweet, peach-like flavor; d-citronellol has a bitter taste.

天然物の起源

l-Citronellol has been found in the plants of the Rosaceae family; d- and dl-citronellol have been identified in Verbenaceae, Labiatae, Rutaceae, Geraniaceae and others; citronellol has been reported in about 70 essential oils and in the oil of Rosa bourbonia; the Bulgarian rose oil has been reported to contain more than 50% l-citronellol, whereas East African geranium contains more than 80% of the d-isomer; the natural product is always optically active. Reported found in guava fruit, orange, bilberry, blackcurrant, nutmeg, ginger, corn mint oil (Mentha arvensis L. var. piperascens), mustard, pennyroyal oil (Mentha pulegium L.), hop oil, tea, coriander seed, cardamom, beer, rum, and apple juice.

使用

citronellol is a constituent of plant essential oils. Found abundantly in eucalyptus oil. It is used for masking odor or providing a fragrance component to a cosmetic product.

定義

ChEBI: A monoterpenoid that is oct-6-ene substituted by a hydroxy group at position 1 and methyl groups at positions 3 and 7.

製造方法

By reduction of citronellal or geraniol or by fractional distillation of such essential oils as geranium and citronella (Bedoukian, 1967).

一般的な説明

Citronellol is a volatile monoterpenic primary alcohol mainly found in the essential oil of plants such as Pelargonium graveolens, Cymbopogon winterianus and Rosa damascena. It is also one of the glycosidically bound aroma compounds in ginger.

安全性プロファイル

Poison by intravenous route. Moderately toxic by ingestion, skin contact, and intramuscular routes. A severe skin irritant. A combustible liquid. When heated to decomposition it emits acrid smoke and irritating fumes. See also ALCOHOLS.

純化方法

Purify them bydistillation through a cannon packed (Ni) column and the main cut collected at 84o/14mm and redistilled. Also purify via the benzoate. [IR: Eschenazi J Org Chem 26 3072 1961, Naves Bull Soc Chim Fr 505 1951, Beilstein 1 IV 2188.]

参考文献

https://eic.rsc.org/magnificent-molecules/citronellol/2000020.article
https://en.wikipedia.org/wiki/Citronellol