ベンジジン

反応性

芳香族アミンの一つ。4,4'-ジアミノビフェニルともいう。ベンジジン    は，無色またはやや赤色の結晶。酸素と光で暗黒色に変化する。冷水には溶けにくく、熱水には溶ける。熱エタノール（エチルアルコール）にはよく溶ける。80℃以上の熱水から再結晶したものは無水和物、60℃以下からは一水和物を生じる。ニトロベンゼンの還元で得られるヒドラゾベンゼンを無機酸と加熱すると、転位反応（ベンジジン転位）がおこって生成する。染料の原料として使われたが、現在は使用を禁止されている。また種々の金属イオンの検出試薬、リン酸イオン、硫酸イオンの沈殿試薬としても用いられる。発癌(はつがん)性が強く、粉末でも蒸気でも皮膚から吸収されるので、取扱いには十分注意する必要がある。［務台　潔］

解説

biphenyl-4,4′-diamine．C12H12N2(184.24)．ヒドラゾベンゼンを希硫酸と加熱して，ベンジジン転位させてつくられる．結晶形は3種類あるが，もっとも安定なものは融点128 ℃，沸点400 ℃(98.6 kPa)．無色の鱗片状結晶。1845年にロシアのジーニンN.N.Zininがはじめて合成し，62年にドイツのフィティヒR.Fittigがジアミノビフェニル構造であることを証明し，74年に同じくドイツのシュルツG.Schultzが2個のアミノ基がともにパラ位にあることを示して構造が確定した。ニトロベンゼンを還元してヒドラゾベンゼンにしたのち，これに塩酸または硫酸を作用させてベンジジン転位を起こすことによって作られる。直接染料の重要な中間物であったが，発がん性があることがわかり，製造されなくなった．分析試薬として多くの金属および非金属イオンの定性，定量に用いられる．森北出版「化学辞典（第2版）

説明

Benzidine is a white, greyish-yellow, or slightly reddish crystalline solid or powder. The major use for benzidine is in the production of dyes, especially azo dyes in the leather, textile, and paper industries and as a synthetic precursor in the preparation and manufacture of dyestuffs. It is also used in the manufacture of rubber, as a reagent, and as a stain in microscopy. It is slightly soluble and slowly changes from a solid to a gas.

化学的特性

Benzidine is a white, grayish-yellow, or slightly reddish crystalline solid or powder. The major use for benzidine is in the production of dyes, especially azo dyes in the leather, textile, and paper industries, as a synthetic precursor in the preparation and manufacture of dyestuffs. It is also used in the manufacture of dyes and rubber, as a reagent, and as a stain in microscopy. It is slightly soluble and slowly changes from a solid to a gas.

物理的性質

Grayish-yellow to pale reddish powder or crystals. Darkens on exposure to air or light. Odorless.

使用

Benzidine was used extensively in the manu facture of dyes. Because of its cancer-causingeffects in humans, its application in dyes hasbeen curtailed. Other uses of this compoundare in chemical analysis: as a reagent for thedetermination of hydrogen peroxide in milkand in the analysis of nicotine. Its hydrochlo ride is used as a reagent to analyze metalsand sulfate.

製造方法

1-Nitrobenzene restore 1,2-Diphenylhydrazine?turn with acid rearrangement.

調製方法

Benzidine production is now exclusively for captive consumption and must be carried out in closed systems under stringent workplace controls. Benzidine is used in the synthesisofdyesanddyeintermediates,asahardenerforrubber, and as a laboratory reagent. The ?rst successful synthetic direct dye was Congo Red, a diazo derivative prepared from benzidinebyBoettigerin1884.Nearlyalldirectdyesareazo products. Congo Red is used in humans intravenously for the medical diagnosis of amyloidosis. The basis for its use is an unexplained af?nity for amyloid, which rapidly removes the dye from the blood. It is used medically for the management of profuse capillary hemorrhage such as the one occurring in septicemias and in the terminal phases of leukemia.

定義

ChEBI: A member of the class of biphenyls that is 1,1'-biphenyl in which the hydrogen at the para-position of each phenyl group has been replaced by an amino group.

一般的な説明

A grayish-yellow to grayish-red, crystalline solid. Toxic by ingestion, inhalation, and skin absorption. Combustion produces toxic oxides of nitrogen. Used to make other chemicals and in chemical and biological analysis.

空気と水の反応

Darkens on exposure to air and light. Soluble in hot water.

反応プロフィール

Benzidine forms insoluble salts with sulfuric acid. Can be diazotized, acetylated and alkylated. Is hypergolic with red fuming nitric acid . Neutralizes acids in exothermic reactions to form salts plus water. May be incompatible with isocyanates, halogenated organics, peroxides, phenols (acidic), epoxides, anhydrides, and acid halides. Flammable gaseous hydrogen may be generated in combination with strong reducing agents, such as hydrides.

危険性

Highly toxic by ingestion, inhalation, and skin absorption. Confirmed carcinogen.

健康ハザード

Exposure to benzidine causes irritation to the eyes. Laboratory animals exposed to benzidine at as low as 0.01% to 0.08% in food showed adverse health effects, such as organ weight decrease in the liver, kidney, and body weight, and an increase in spleen weight, swelling of the liver, and blood in the urine. Exposure may cause an increase in urination, blood in the urine, and urinary tract tumors. Benzidine is considered acutely toxic to humans by ingestion, with an estimated oral lethal dose of between 50 and 500 mg/kg. The symptoms of acute ingestion exposure include cyanosis, headache, mental confusion, nausea, and vertigo. Dermal exposure may cause skin rashes and irritation. Prolonged exposure to benzidine causes bladder injury in humans

安全性プロファイル

Confirmed human carcinogen producing bladder tumors. Experimental carcinogenic and tumorigenic data. Poison by ingestion and intraperitoneal routes. Human mutation data reported. Can cause damage to blood, including hemolysis and bone marrow depression. On ingestion causes nausea and vomiting, which may be followed by liver and kidney damage. Any exposure is considered extremely hazardous. When heated to decomposition it emits highly toxic fumes of NOx. See also AROMATIC AMINES.

発がん性

Benzidine is known to be a human carcinogen based on sufficient evidence of carcinogenicity from studies in humans.

環境運命予測

Biological. In activated sludge, <0.1% mineralized to carbon dioxide after 5 d (Freitag et al., 1985). Kincannon and Lin (1985) reported a half-life of 76 d when benzidine in sludge was applied to a sandy loam soil.
Soil. Benzidine was added to different soils and incubated in the dark at 23 °C under a carbon dioxide-free atmosphere. After 1 yr, 8.3 to 11.6% of the added benzidine degraded to carbon dioxide primarily by microbial metabolism and partially by hydrolysis (Graveel et al., 1986). Tentatively identified biooxidation compounds using GC/MS include hydroxybenzidine, 3- hydroxybenzidine, 4-amino-4′-nitrobiphenyl, N,N′-dihydroxybenzidine, 3,3′-dihydroxybenzidine and 4,4′-dinitrobiphenyl (Baird et al., 1977). Under aerobic conditions, the half-life was estimated to be 2 to 8 d (Lu et al., 1977).
Chemical/Physical. Benzidine is not subject to hydrolysis (Kollig, 1993). Reacts with HCl forming a salt (C12H12N2?2HCl) that is very soluble in water (61.7 mg/L at 25 °C) (Bowman et al., 1976).

貯蔵

Benzidine should be kept stored in a cool, well-ventilated area, in closed, sealed containers and out of sunlight and away from heat.

輸送方法

UN1885 Benzidine, Hazard Class: 6.1; Labels: 6.1—Poisonous materials. PGII.

純化方法

Its solution in *benzene is decolorized by percolating through two 2-cm columns of activated alumina, then concentrated until benzidine crystallises on cooling. Recrystallise alternately from EtOH and *benzene to constant absorption spectrum [Carlin et al. J Am Chem Soc 73 1002 1951]. It has also been crystallised from hot water (charcoal) and from diethyl ether. Dry it under vacuum in an Abderhalden pistol. Store it in the dark in a stoppered container. CARCINOGENIC. [Beilstein 13 IV 364.]

不和合性

Dust may form explosive mixture with air. Incompatible with oxidizers (chlorates, nitrates, peroxides, permanganates, perchlorates, chlorine, bromine, fluorine, etc.); contact may cause fires or explosions. On contact with strong reducing agents, such as hydrides may form flammable gases. Keep away from alkaline materials, strong bases, strong acids, oxoacids, epoxides. Contact with red fuming nitric acid may cause fire. Oxidizes in air. Neutralizes acids in exothermic reactions to form salts plus water. May be incompatible with isocyanates, halogenated organics, peroxides, phenols (acidic), epoxides, anhydrides, and acid halides.

廃棄物の処理

Incineration; oxides of nitrogen are removed from the effluent gas by scrubber, catalytic or thermal device. Package spill residues and sorbent media in 17 hour epoxy-lined drums and move to an EPA-approved disposal site. Treatment may include destruction by potassium permanganate oxidation, hightemperature incineration, or microwave plasma methods. 398 Benzidine Encapsulation by organic polyester resin or silicate fixation. These disposal procedures should be confirmed with responsible environmental engineering and regulatory officials.

予防処置

At high temperatures, benzidine breaks down and releases highly poisonous fumes. During use and handling, workers should wear butyl rubber gloves, goggles, and full body plastic coveralls and ensure that no skin is exposed.