ヒドロキノン 化学特性,用途語,生産方法
外観
白色〜ほとんど白色, 結晶〜結晶性粉末
定義
本品は、次の化学式で表される芳香族化合物である。
性質
1,4-benzenediol．C6H6O2(110.11)．C6H4(OH)2．ヒドロキノンは，キノールともいう．ベンゾキノンを還元すると得られる．結晶．融点169 ℃，沸点287 ℃(97 kPa)．d20"1.332．285 ℃ で昇華する．λmax 225，293 nm(log ε 3.71，3.43)．pKa1 9.91，pKa2 12.04(30 ℃，水)．水，エタノール，エーテルなどに易溶．水溶液は還元性が強く，写真の現像薬として用いられる．また，同じ理由で，酸化防止剤，重合防止剤ともなる．種々の合成中間体のほか，分析試薬として，リン，ヒ素，ケイ酸の定量にも用いられる．森北出版「化学辞典（第2版）
溶解性
熱水、エタノール及びジエチルエーテルに溶けやすく、冷水にやや溶けやすい。水, エタノール, エーテルに可溶 : 冷べンゼンに難溶．
解説
二価フェノールの一つ。ハイドロキノン、キノールともよばれる。ヒドロキノンの名は、キノンに水素（2原子）がついた組成をもつことを意味している。カテコールやレゾルシンはヒドロキシ基-OHの位置が異なる異性体である。分子式C6H6O2、分子量110.1。
以前はアニリンを酸化してp(パラ)-ベンゾキノンにしたのちに、亜硫酸により還元して製造していたが、現在ではベンゼンとプロピレンからジイソプロピルベンゼン法により製造している。この方法では、ヒドロキノンとレゾルシン（m(メタ)-ジヒドロキシベンゼン）の両方ができる（図）。無色の針状結晶。熱水、エタノール（エチルアルコール）、エーテルなどにはよく溶けるが、冷水には100ミリリットルに対して5.8グラムしか溶けない。還元性をもち、とくにアルカリ性水溶液は還元性が強い。写真現像剤、酸化防止剤としての用途をもつ。医薬部外品であり、クリーム・軟膏(なんこう)として使われているが、発癌(はつがん)性が疑われていて、2％以上の高濃度の配合は制限されている。［廣田 穰 2015年7月21日］
用途
電球、軽合金のメッキ
用途
写真現像薬、ゴム酸化防止剤、染料等の中間合成原料
用途
写真用、有機合成原料、重合防止剤。
用途
白黒写真現像液の材料。
用途
写真用、分析用還元剤。
化粧品の成分用途
還元剤、毛髪着色剤、皮膚ブリーチ剤、酸化防止剤、香料
効能
皮膚漂白作用, チロシナーゼ阻害薬
使用上の注意
空気中で次第に着色する。
説明
Hydroquinone (HQ) is produced by the oxidation of aniline or
phenol, by the reduction of quinone, or from a reaction of
acetylene and carbon monoxide. Hydroquinone occurs naturally
as a glucose ether, also known as arbutin, in the leaves of
many plants and in fruits, as well as one of the agents used in the
defense mechanism of the bombardier beetle, family Carabidae.
化学的特性
Hydroquinone, a colorless, hexagonal prism, has been reported to be a good antimitotic
and tumor-inhibiting agent. It is a reducing agent used in a photographic developer,
which polymerizes in the presence of oxidizing agents. In the manufacturing industry
it may occur include bacteriostatic agent, drug, fur processing, motor fuel, paint, organic
chemicals, plastics, stone coating, and styrene monomers.
物理的性質
Colorless to pale brown, odorless, hexagonal crystals
使用
hydroquinone is a pigment-lightening agent used in bleaching creams. Hydroquinone combines with oxygen very rapidly and becomes brown when exposed to air. Although it occurs naturally, the synthetic version is the one commonly used in cosmetics. Application to the skin may cause allergic reaction and increase skin sun sensitivity. Hydroquinone is potentially carcinogenic and is associated with causing ochronosis, a discoloration of the skin. The u.S. FDA has banned hydroquinone from oTC cosmetic formulations, but allows 4 percent in prescription products. Its use in cosmetics is prohibited in some european countries and in Australia.
定義
ChEBI: A benzenediol comprising benzene core carrying two hydroxy substituents para to each other.
適応症
Hydroquinone interferes with the production of the
pigment melanin by epidermal melanocytes through at
least two mechanisms: it competitively inhibits tyrosinase,
one of the principal enzymes responsible for converting
tyrosine to melanin, and it selectively damages
melanocytes and melanosomes (the organelles within
which melanin is stored).
調製方法
There are three current manufacturing processes for HQ:
oxidative cleavage of diisopropylbenzene, oxidation of aniline,
and hydroxylation of phenol.
Diisopropylbenzene is air oxidized to the intermediate
diisopropylbenzene bishydroperoxide. This hydroperoxide
is purified by extraction and reacted further to form
hydroquinone. The purified product is isolated by filtration
and packaged. The process can be almost entirely closed,
continuous, computer-controlled, and monitored.
HQcan also be prepared by oxidizing aniline to quinone in
the presence of manganese dioxide and sulfuric acid.
p-Benzoquinone is then reduced to HQ using iron oxide.
The resulting hydroquinone is crystallized and dried.
The process occurs in a closed system.
HQis also manufactured by hydroxylation of phenol using
hydrogen peroxide as a hydroxylation agent. The reaction is
catalyzed by strong mineral acids or ferrous or cobalt salts.
世界保健機関（WHO）
Hydroquinone was introduced in 1965 as a topical depigmenting
agent for hyperpigmentation. At high concentrations hydroquinone is corrosive
and in most countries has been restricted to the level of approximately 2% and
limited to the period of less than 2 months. Additional consideration for restrictive
action is that animal experiments have also demonstrated carcinogenic and
mutagenic potential of hydroquinone.
一般的な説明
Light colored crystals or solutions. May irritate the skin, eyes and mucous membranes. Mildly toxic by ingestion or skin absorption.
空気と水の反応
Darkens on exposure to air and light. Miscible in water. Solutions become brown in air due to oxidation. Oxidation is very rapid in the presence of alkali.
反応プロフィール
Hydroquinone is a slight explosion hazard when exposed to heat. Incompatible with strong oxidizing agents. Also incompatible with bases. Hydroquinone reacts with oxygen and sodium hydroxide. Reacts with ferric salts . Hot and/or concentrated NaOH can cause Hydroquinone to decompose exothermically at elevated temperature. (NFPA Pub. 491M, 1975, 385)
危険性
Toxic by ingestion and inhalation, irritant.
Questionable carcinogen.
健康ハザード
Hydroquinone is very toxic; the probable oral lethal dose for humans is 50-500 mg/kg, or between 1 teaspoon and 1 ounce for a 150 lb. person. It is irritating but not corrosive. Fatal human doses have ranged from 5-12 grams, but 300-500 mg have been ingested daily for 3-5 months without ill effects. Death is apparently initiated by respiratory failure or anoxia.
火災危険
Dust cloud may explode if ignited in an enclosed area. Hydroquinone can react with oxidizing materials and is rapidly oxidized in the presence of alkaline materials. Oxidizes in air.
接触アレルゲン
Hydroquinone is used in photography developers (black
and white, X-ray, and microfilms), in plastics, in hair
dyes as an antioxidant and hair colorant. Hydroquinone
is found in many skin bleaching creams.
臨床応用
Hydroquinone is applied topically to treat disorders
characterized by excessive melanin in the epidermis,
such as melasma. In the United States, nonprescription
skin-lightening products contain hydroquinone at concentrations
of 2% or less; higher concentrations are
available by prescription.
副作用
The incidence of adverse effects with hydroquinone
increases in proportion to its concentration. A relatively
common side effect is local irritation, which may actually
exacerbate the discoloration of the skin being
treated. Allergic contact dermatitis occurs less commonly.
A rare but more serious complication is exogenous
ochronosis, in which a yellow-brown pigment deposited
in the dermis results in blue-black pigmentation
of the skin that may be permanent.
発がん性
No case reports of cancer associated
with HQ exposure have been published.
純化方法
Crystallise quinol from acetone, *benzene, EtOH, EtOH/*benzene, water or acetonitrile (25g in 30mL), preferably under nitrogen. Dry it under vacuum. [Wolfenden et al. J Am Chem Soc 109 463 1987, Beilstein 6 H 836, 6 IV 5712.]
ヒドロキノン 上流と下流の製品情報
原材料
準備製品
抱水クロラール
tert-ブチルヒドロキノン
4-クロロ-2,5-ジメトキシアニリン
3,3-ジメチル-4-ペンテン酸エチル
フルアジホップ-P-ブチル標準品
アクリル酸ヒドロキシプロピル (2-ヒドロキシプロピルエステル, 2-ヒドロキシ-1-メチルエチルエステル混合物)
1-(2,5-Dimethoxyphenyl)-2-oximino-1-propanone
7-HYDROXYISOFLAVONE
4-クロロ-8-(トリフルオロメチル)キノリン
ｔ－ブチルヒドロキシアニソール
α-シアノアクリル酸ブチル
2-AMINO-1-(2,5-DIMETHOXYPHENYL)-1-PROPANONE
ピレノキシン
2-ジシクロヘキシルホスフィノ-2',4',6'-トリイソプロピルビフェニル
3-メチルスルホレン
2,6-ジクロロ-4-ニトロ-4'-[2-シアノエチル(2-アセトキシエチル)アミノ]アゾベンゼン
ammonium manganous sulfate
1,2,4-トリメトキシベンゼン
クロロ(1,5-シクロオクタジエン)イリジウム(I) (ダイマー)
3-スルホレン
フルアジホップ-ブチル
メタクリル酸2-ヒドロキシエチル
2,2-ジメチル-3-(2-メチル-1-プロペニル)シクロプロパン-1-カルボン酸メチル
アクリル酸ノニル
アゾイックジアゾコンポーネント20 (ベース)
2,3-ジメチル-1,3-ブタジエン
ゲンチシン酸
4-[(6-クロロ-2-ベンゾオキサゾリル)オキシ]フェノール
4-フェノキシフェノール
1,4-ジメトキシベンゼン
1,4-ジアセトキシベンゼン
2-CHLOROPYRIMIDINE-4-CARBONITRILE
2,5-ジメトキシアニリン
2,5-ジ-tert-ブチルヒドロキノン
2,2-ジメチル-3-(2-メチル-1-プロペニル)シクロプロパン カルボン酸 エチル
キザロホップ-P-エチル標準品
1,2-ナフタル酸無水物
ヘキサン酸アリル
(1,1-DIMETHYL-PROP-2-YNYL)-HYDRAZINE
酢酸4-ビニルフェニル