アシッド オレンジ 7

外観

黄赤色～赤みの黄色、粉末

定義

本品は、平成15年厚労省令第126号に示されるだいだい色205号又はそのアルミニウムレーキ又はそのバリウムレーキ又はそのジルコニウムレーキである。

溶解性

エタノールに溶けて、赤黄色～黄赤色を呈する。

解説

オレンジⅡ．C.I.15510，C.I.Acid Orange 7ともいう．スルファニル酸のジアゾニウム塩をアルカリ性水溶液中で2-ナフトールとカップリングさせると得られる．水に可溶．羊毛やナイロン用オレンジ色酸性染料．細胞の染色，レーキ顔料の製造，酸塩基指示薬としても使用される．pH 7.4～8.6でこはく色からオレンジ色，pH 10.2～11.8でオレンジ色から赤色を呈する．

化粧品の成分用途

着色剤

化学的特性

Orange-red powder

定義

ChEBI: Acid orange 7 is a member of naphthalenes. Orange allergenic extract is used in allergenic testing.

製造方法

Acid Orange 7, commonly known as acidic orange II. 4-Aminobenzenesulfonic acid diazo, and Naphthalen-2-ol coupling. It is produced by azo coupling of β-naphthol and diazonium derivative of sulfanilic acid.

純化方法

Purification is as for Orange I. Its solubility in H2O is 40g/L at 25o. [Müller et al. Helv Chim Acta 35 2579 1952.] Also purify it by extracting it with a small volume of cold water, then crystallising it by dissolving in boiling water, cooling to ca 80o, adding two volumes of EtOH and cooling. When cold, the precipitate is filtered off, washed with a little EtOH and dried in air. It can be salted out from aqueous solution with sodium acetate, then repeatedly extracted with EtOH. Meggy and Sims [J Chem Soc 2940 1956], after crystallising the sodium salt twice from water, dissolved it in cold water (11mL/g) and added conc HCl to precipitate the acid dye which was separated by centrifugation, redissolved and again precipitated with acid. After washing the precipitate three times with 0.5M acid, it was dried over NaOH, recrystallised twice from absolute EtOH, washed with a little Et2O, dried over NaOH and stored over conc H2SO4 in the dark. It can then be converted to the pure salt with the calculated amount of NaOH or Na2CO3. [Beilstein 16 IV 408.]