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| 融点 | 5.5 °C (lit.) | | 沸点 | 80 °C (lit.) | | 比重(密度) | 0.874 g/mL at 25 °C (lit.) | | 蒸気密度 | 2.77 (vs air) | | 蒸気圧 | 166 mm Hg ( 37.7 °C) | | 屈折率 | n20/D 1.501(lit.) | | 闪点 | 12 °F | | 貯蔵温度 | room temp | | 溶解性 | Miscible with alcohol, chloroform, dichloromethane, diethyl ether, acetone and acetic acid. | | 酸解離定数(Pka) | 43(at 25℃) | | 外見 | Liquid | | 色 | APHA: ≤10 | | 臭い (Odor) | Paint-thinner-like odor detectable at 12 ppm | | Relative polarity | 0.111 | | 爆発限界(explosive limit) | 1.4-8.0%(V) | | 臭気閾値(Odor Threshold) | 2.7ppm | | 水溶解度 | 0.18 g/100 mL | | 極大吸収波長 (λmax) | λ: 280 nm Amax: 1.0
λ: 290 nm Amax: 0.15
λ: 300 nm Amax: 0.06
λ: 330 nm Amax: 0.02
λ: 350-400 nm Amax: 0.01 | | Merck | 14,1066 | | BRN | 969212 | | Henry's Law Constant | 10.4 at 45.00 °C, 11.4 at 50.00 °C, 13.3 at 55.00 °C, 14.5 at 60.00 °C, 16.8 at 65.00 °C, 19.2 at
70.00 °C (static headspace-GC, Park et al., 2004) | | 暴露限界値 | TLV-TWA 10 ppm (～32 mg/m3) (ACGIH
and OSHA); ceiling 25 ppm (～80 mg/m3)
(OSHA and MSHA); peak 50 ppm (～160
mg/m3)/10 min/8 h (OSHA); carcinogenicity:
Suspected Human Carcinogen (ACGIH),
Human Sufficient Evidence (IARC). | | Dielectric constant | 2.3（20℃） | | 安定性： | Stable. Substances to be avoided include strong oxidizing agents, sulfuric acid, nitric acid, halogens. Highly flammable. | | InChIKey | UHOVQNZJYSORNB-UHFFFAOYSA-N | | LogP | 2.130 | | CAS データベース | 71-43-2(CAS DataBase Reference) | | IARC | 1 (Vol. 29, Sup 7. 100F, 120) 2018 | | NISTの化学物質情報 | Benzene(71-43-2) | | EPAの化学物質情報 | Benzene (71-43-2) |
| 外観 | 無色澄明の液体 | | 溶解性 | 水に微溶。エタノール、エーテルと混和。 | | 解説 | ベンゼン，benzole．C6H6(78.11)．石油改質中に，また石炭を乾留したときのガスおよびタール中に多量に含まれ，工業的にこれらから分離，精製する．すなわち，石油精製工業においては，ナフサを接触改質してベンゼン，トルエン，キシレンなどの芳香族炭化水素に富む改質油にかえ，スルホラン法，その他によって芳香族のみを抽出し，さらに分留してトルエン，キシレン，そのほかの留分と分ける．また，トルエンやキシレンの脱メチル水素化法で製造するときには，Cr2O3，Mn2O3，CoOなどの担持触媒による接触反応で処理し，メチル基をメタンとして除去して製造される．ベンゼンは，芳香族炭化水素の代表的な化合物であり，芳香族特有の香りをもつ，無色，揮発性の液体で，人体には有毒である．融点5.5 ℃，沸点80.1 ℃．d2540.8737．n25D1.4979．比熱容量1.734 J K－1 mol－1(21.8 ℃)．蒸発熱392.6 J g－1(沸点)．引火性が強く引火点－11.10 ℃．λmax 198，256 nm(ε 8000，230)．エタノール，エーテルなど多くの有機溶媒に可溶，水に難溶．水29.6物質量％ で沸点69.25 ℃(101 kPa)の最低共沸混合物をつくる．ベンゼンの構造は正六角形の平面であり，C-C0.1397 nm，C-H0.1084 nm，∠C-C-Cおよび∠H-C-Cはすべて120°である．ベンゼンは化学的に安定な化合物であるが，強力な試薬によって置換反応および付加反応を受ける．とくにニトロ化，ハロゲン化，スルホン化，あるいはフリーデル-クラフツ反応のような親電子置換反応は，ベンゼンの代表的な反応であり，これによってきわめて多種類の置換ベンゼン誘導体が合成され，これらは芳香族系合成化学，ならびにその工業の中間物として重要なものが多い．付加反応においては，塩素をラジカル的に付加させるとヘキサクロロシクロヘキサン(BHC)となり，水素を付加させるとシクロヘキサンが得られる．また，ニトロベンゼン，クロロベンゼンを経て多数のベンゼン誘導体に導き，染料，医薬，農薬などの中間物として用いられる．LD50 3800 mg/kg(ラット，経口)． | | 用途 | 汎用試薬、溶剤、有機合成原料。 | | 用途 | 高速液体クロマトグラフィーの溶離液及び溶離液の調製。 | | 用途 | 本物質の主な用途は、純ベンゼンでは合成原料として染料、合成ゴム、合成洗剤、有機顔料、有機ゴム薬品、医薬品、香料、合成繊維(ナイロン)、合成樹脂(ポリスチレン、フェノール、ポリエステル)、食品(コハク酸、ズルチン)、農薬(2,4-D、クロルピクリンなど)、可塑剤、写真薬品、爆薬(ピクリン酸)、防虫剤(パラジクロロベンゼン)、防腐剤(PCP)、絶縁油(PCD)、熱媒、溶剤級ベンゼンでは塗料、農薬、医薬品など一般溶剤、油脂、抽出剤、石油精製など、その他アルコール変性用である | | 用途 | 機器及び比色分析における低バックグラウンド抽出溶媒、高純度溶剤。 | | 用途 | 汎用試薬、高純度を要する溶剤等。 | | 用途 | アミノ酸配列分析における溶剤。 | | 用途 | 薄層及びペーパークロマトグラフィーの展開溶媒。 | | 用途 | 分解ガソリン等から抽出される芳香族炭化水素で、スチレン、フェノール、シクロヘキサン等の原料として使用される他、各種化学品の原料、溶剤等に使用されます。
| | 用途 | 精密分析、超高純度溶剤としての個人専用試薬。 | | 用途 | 食品及び水中等の農薬及びPCB定量における溶媒。 | | 用途 | 各種化学製品の中間体製造のための出発原料として重要である。ベンゼンはアルキルベンゼン、フェノール、アニリン、スチレン、クロロベンゼン、ニトロベンゼン、無水マレイン酸などの合成原料であり、これらからさらに各種の樹脂、繊維、洗剤、染料、殺虫剤、爆薬、医薬品などが誘導される（図）。 | | 使用上の注意 | 不活性ガス封入 | | 性質と構造 | 特有のにおいをもつ無色透明で可燃性の液体で、煤(すす)の多い黒い煙をあげて燃える。その蒸気は有毒である。水には難溶だが、エタノール（エチルアルコール）やエーテルとは任意の割合で混じり合う。大気中のベンゼンは有害大気汚染物質と定められていて、長期間吸収すると造血器の障害をおこし、貧血などの原因になる。白血病などの癌(がん)性疾患を引き起こすともいわれている。 1825年にイギリスのM・ファラデーにより、鯨油の赤熱分解で得られたガスを凝縮させた液体中から最初に発見され、発見当時からその構造と化学的特性に関心が集まった。1865年、ドイツのF・A・ケクレが有名な亀甲(きっこう)形の六角環状説（ベンゼン環）を提案したが、最終的には1930年代になって、ようやくX線および電子線回折測定により正確な構造が決められた。それによると、ベンゼン環は1辺が0.1399ナノメートルの正六角形で、6本の炭素‐炭素（C-C）結合はまったく同等であり、6個のπ(パイ)電子が3本の二重結合に2個ずつ局在化しているのではなく、6個の炭素に平等に共有され、非局在化していることが証明された。ベンゼンの構造、性質が解明される過程において芳香族化合物の化学は発展し、この意味でも化学に果たした役割は非常に大きい。 | | 説明 | Benzene is a colorless, volatile, highly flammable liquid that is used extensively in the chemical industry and received wide interest in the early days of organic chemistry.
Because of its structure, benzene is a very stable organic compound. It does not readily undergo addition reactions. Addition reactions involving benzene require high temperature, pressure, and special catalysts. The most common reactions involving benzene involve substitution reactions. Numerous atoms and groups of atoms may replace a hydrogen atom or several hydrogen atoms in benzene. Th ree important types of substitution reactions involving benzene are alkylation, halogenation, and nitration. In alkylation, an alkyl group or groups substitute for hydrogen(s). | | 化学的特性 | Benzene is a clear, volatile, colorless, highly flammable liquid with a pleasant, characteristic odor. It is an aromatic hydrocarbon that boils at 80.1 DC. Benzene is used as a solvent in many areas of industries, such as rubber and shoe manufacturing, and in the production of other important substances, such as styrene, phenol, and cyclohexane. It is essential in the manufacture of detergents, pesticides, solvents, and paint removers. It is present in fuels such as gasoline up to the level of 5%. | | 物理的性質 | Clear, colorless to light yellow watery liquid with an aromatic, musty, phenolics or gasoline-like
odor. At 40 °C, an odor threshold concentration of 190 μg/L in air was determined by Young et al.
(1996). An odor threshold of 4.68 ppmv was determined by Leonardos et al. (1969). A detection
odor threshold concentration of 108 mg/m3 (34 ppmv) was reported by Punter (1983). The average
least detectable odor threshold concentrations in water at 60 °C and in air at 40 °C were 0.072 and
0.5 mg/L, respectively (Alexander et al., 1982). | | 天然物の起源 | Detectable levels of benzene have been found in a number of soft drinks that contain either a sodium or potassium benzoate preservative and ascorbic acid, and 'diet' type products containing no added sugar are reported to be particularly likely to contain benzene at detectable levels. Surveys carried out in the USA, the UK and Canada have all confirmed that a small proportion of these products may contain low levels of benzene. For example, in a survey of 86 samples analysed by the FDA between April 2006 and March 2007, only five products were found to contain benzene at concentrations above 5 ug kg-1. The levels found were in a range from approximately 10–90 ug kg-1. A survey of 150 UK-produced soft drinks by the Food Standards Agency (FSA) published in 2006 showed that four products contained benzene at levels above 10 ug kg-1, and the highest level recorded was 28 ug kg-1. However, it has been reported that higher levels may develop in these products during prolonged storage, especially if they are exposed to daylight.
Benzene may also be formed in some mango and cranberry drinks in the absence of added preservatives, because these fruits contain natural benzoates. | | 来歴 | Benzene was discovered in 1825 by Michael Faraday (1791–1867), who identified it in a liquid residue from heated whale oil. Faraday called the compound bicarburet of hydrogen, and its name was later changed to benzin by Eilhardt Mitscherlich (1794–1863), who isolated the compound from benzoin (C14H12O2). | | 使用 | Benzene is also converted to cyclohexane, which is used to produce nylon and synthetic fibers. | | 使用 | Benzene occurs in coal and coal-tar distillationproducts and in petroleum products suchas gasoline. It is also found in the gases andleachates of landfills for industrial wastes,construction debris, and landscaping refuse(Oak Ridge National Laboratory 1989). Traceamounts of benzene, toluene, xylenes, andother volatile organics have been found inthe soils and groundwaters near many sanitarylandfills (U.S. EPA 1989a,b). Kramer(1989) has assessed the level of exposuresto benzene during removal, cleaning, pumping,and testing of underground gasoline storagetanks. The average human exposureswere 0.43–3.84 ppm (in 1.5–6 hours) and thehighest short-term (15–minute) exposure was9.14 ppm. Benzene also occurs in the tobaccosmoke (Hoffmann et al. 1989); thus the riskof its exposure may enhance from inhalingsuch smoke.
Benzene is used as a solvent for waxes,resins, and oils; as a paint remover; as a diluentfor lacquers; in the manufacture of dyes,pharmaceuticals, varnishes, and linoleum;and as a raw material to produce a numberof organic compounds. | | 使用 | Benzene is also known as benzol, benzole, coal tar naphtha, and phenyl
hydride, benzene is a clear, colorless, flammable liquid made by
passing coke gas through oil, which is then distilled to produce
benzene and toluol. The benzene is separated from the toluol
by fractional distillation. Benzene is soluble in alcohol, ether,
chloroform, and glacial acetic acid, but it is insoluble in water.
Benzene was used as a solvent for many photographic operations
in the 19th century. In the collodion process, benzene
was used to dissolve rubber to both subcoat and supercoat
negatives. It was also used as a solvent for Canada balsam in
the Cutting method of sealing ambrotypes and cementing lens
elements. Benzene was also used as a solvent for wax, gums,
resins, and amber and in particular for retouching varnishes
applied to silver bromide gelatin negatives. | | 使用 | Manufacturing of ethylbenzene (for styrene
monomer), dodecylbenzene (for detergents), cyclo-
hexane (for nylon), phenol, nitrobenzene (for ani-
line), maleic anhydride, chlorobenzene, diphenyl,
benzene hexachloride, benzene-sulfonic acid, and
as a solvent. | | 定義 | ChEBI: Benzene is a six-carbon aromatic annulene in which each carbon atom donates one of its two 2p electrons into a delocalised pi system. A toxic, flammable liquid byproduct of coal distillation, it is used as an industrial solvent. Benzene is a carcinogen that also damages bone marrow and the central nervous system. | | 調製方法 | Today benzene, which is a natural component of petroleum, is obtained from petroleum by several processes. Toluene hydrodealkylation involves mixing toluene (C6H5CH3) and hydrogen in the presence of catalysts and temperatures of approximately 500°C and pressures of about 50 atmospheres to produce benzene and methane: C6H5CH3 + H2 → C6H6 + CH4. Hydrodealkylation strips the methyl group from toluene to produce benzene. Toluene disproportionation involves combining toluene so that the methyl groups bond to one aromatic ring, producing benzene and xylene. Benzene can also be obtained from petroleum reforming in which temperature, pressure, and catalysts are used to convert petroleum components to benzene, which can then be extracted using solvents and distillation processes. Another source of benzene is pyrolysis gasoline or pygas. | | 反応性 | Benzene reacts (1) with chlorine, to form (a) substitution products (one-half of the chlorine forms hydrogen chloride) such as chlorobenzene, C6H5Cl; dichlorobenzene, C6H4Cl2(1,4) and (1,2); trichlorobenzene, C6H3Cl3(1,2,4); tetrachlorobenzene (1,2,3,5); and (b) addition products, such as benzene dichloride C6H6Cl2; benzene tetrachloride, C6H6Cl4; and benzene hexachloride, C6H6Cl6. The formation of substitution products of the benzene nucleus, whether in benzene or its homologues, is favored by the presence of a catalyzer, e.g., iodine, phosphorus, iron; (2) with concentrated HNO3, to form nitrobenzene, C6H5NO2; 1,3- dinitrobenzene, C6H4(NO2)2 (1,3), 1,3,5-trinitrobenzene, C6H3(NO2)3 (1,3,5); (3) with concentrated H2SO4, to form benzene sulfonic acid, C6H5SO3H, benzene disulfonic acid, C6H4(SO3H)2(1,3), benzene trisulfonic acid, C6H3(SO3H)3 (1,3–5); (4) with methyl chloride plus anhydrous aluminum chloride (Friedel-Crafts reaction) to form toluene, monomethyl benzene, C6H5CH3; dimethyl benzene C6H4(CH3)2; trimethyl benzene, C6H3(CH3)3; (5) with acetyl chloride plus anhydrous aluminum chloride (Friedel-Crafts reaction) to form acetophenone (methylphenyl ketone), C6H5COCH3. | | 反応 | 芳香族性として知られているπ電子の非局在化によりベンゼン環が安定化していて壊れにくいので、ベンゼン誘導体はベンゼン環が失われる付加反応ではなく、反応の後にもベンゼン環が残る置換反応をおこしやすいという特徴がある。ベンゼンの置換反応としては、次の(1)～(4)などが代表的であり、これらの反応はいずれもベンゼン置換体の重要な合成法である。 (1)硝酸と硫酸混合物によるニトロベンゼンの生成（ニトロ化） (2)発煙硫酸によるベンゼンスルホン酸の生成（スルホン化）(3)鉄粉を触媒とする塩素、臭素などのハロゲンとの反応によるクロロベンゼンやブロモベンゼンの生成（ハロゲン化）(4)塩化アルミニウムを触媒としたアルキル化によるアルキルベンゼンの生成、ならびにアシル化によるアセトフェノンなどの芳香族ケトンの生成（フリーデル‐クラフツ反応）。 これら(1)～(4)の反応では陽イオン試薬がπ電子（負電荷）をもつベンゼン環に反応しているので、芳香族求電子置換反応と総称されている。 しかし、次の(5)～(7)の例のように、高温、高圧といった強い反応条件下では、ベンゼン環への付加やベンゼン環が開環する反応もみられる。 (5)白金触媒やニッケル触媒を用いる水素化によるシクロヘキサンの生成 (6)接触気相酸化による無水マレイン酸などの合成(7)光を照射しながら塩素を反応させてBHC（ベンゼンヘキサクロリドの略、別名1,2,3,4,5,6-ヘキサクロロシクロヘキサン）を得る反応。 | | 製法 | 石炭タールまたは石油から製造されている。しかし、芳香族炭化水素の石油中に含まれる量は少ないので、石油化学工業ではナフサの接触分解、リホーミングによりベンゼンのみならずトルエン、キシレンを含む炭化水素油をつくり、これから分留してベンゼンを製造する。またアルキルベンゼンのような高級同族体からは、脱アルキル化、水素化分解法によりベンゼンを得ている。 | | 一般的な説明 | Benzene appears as a clear colorless liquid with a petroleum-like odor. Flash point less than 0 °F. Less dense than water and slightly soluble in water. Hence floats on water. Vapors are heavier than air. | | 空気と水の反応 | Highly flammable. Slightly soluble in water. | | 反応プロフィール | Benzene reacts vigorously with allyl chloride or other alkyl halides even at minus 70°C in the presence of ethyl aluminum dichloride or ethyl aluminum sesquichloride. Explosions have been reported [NFPA 491M 1991]. Ignites in contact with powdered chromic anhydride [Mellor 11:235 1946-47]. Incompatible with oxidizing agents such as nitric acid. Mixtures with bromine trifluoride, bromine pentafluoride, iodine pentafluoride, iodine heptafluoride and other interhalogens can ignite upon heating [Bretherick 5th ed. 1995]. Benzene and cyanogen halides yield HCl as a byproduct (Hagedorn, F. H. Gelbke, and Federal Republic of Germany. 2002. Nitriles. In Ullman Encyclopedia of Industrial Chemistry. Wiley-VCH Verlag GmbH & Co. KGaA.). The reaction of Benzene and trichloroacetonitrile evolves toxic chloroform and HCl gasses. (Hagedorn, F., H.-P. Gelbke, and Federal Republic of Germany. 2002. Nitriles. In Ullman Encyclopedia of Industrial Chemistry. Wiley-VCH Verlag GmbH & Co. KGaA.). | | 危険性 | The acute toxicity of benzene is low. Inhalation of benzene can cause dizziness, euphoria, giddiness, headache, nausea, drowsiness, and weakness. Benzene can cause moderate irritation to skin and severe irritation to eyes and mucous membranes. Benzene readily penetrates the skin to cause the same toxic effects as inhalation or ingestion. The chronic toxicity of benzene is significant. Exposure to benzene affects the blood and blood-forming organs such as the bone marrow, causing irreversible injury; blood disorders including anemia and leukemia may result. The symptoms of chronic benzene exposure may include fatigue, nervousness, irritability, blurred vision, and labored breathing. Benzene is regulated by OSHA as a carcinogen (Standard 1910.1028) and is listed in IARC Group 1 ("carcinogenic to humans"). This substance is classified as a "select carcinogen" under the criteria of the OSHA Laboratory Standard. | | 健康ハザード | Benzene is an acute as well as a chronictoxicant. The acute toxic effects from inhalation,ingestion, and skin contact are low tomoderate. The symptoms in humans are hallucination,distorted perception, euphoria, somnolence,nausea, vomiting, and headache. Thenarcotic effects in humans may occur frominhaling benzene in air at a concentrationof 200 ppm. High concentrations may cause convulsions. A 5- to 10-minute exposure to2% benzene in air may be fatal. Death mayresult from respiratory failure.
Benzene is an irritant to the eyes, nose,and respiratory tract. The chronic poisoningfrom benzene is much more severe than itsacute toxicity. The target organs to acuteand chronic poisoning are the blood, bonemarrow, central nervous system, respiratorysystem, eyes, and skin. Heavy occupationalexposures to benzene can cause bone marrowdepression and anemia, and in rare cases,leukemia. Leukemia may develop severalyears after the exposure ceases. Deaths fromleukemia, attributed to occupational exposureto benzene in the workplace, which may beon the order of 200 ppm concentration, havebeen documented (ACGIH 1986). Benzene islisted as a suspected human carcinogen. Inaddition to leukemia, malignant lymphoma,and myeloma, lung cancer in subjects exposedto benzene has been reported (Aksoy 1989).
Absorption of liquid benzene through theskin may be harmful. The main eliminationpathway for benzene absorbed throughinhalation or skin contact is metabolism.Hydroxyl radicals play an important role inthe process of metabolism. Khan and coworkers(1990) have reported the formationof formaldehyde and degradation of deoxyribose,suggesting the generation of hydroxylradicals during benzene toxicity to the bonemarrow S-9 fraction. The hydroxyl radicalsreact with benzene to form phenols and dihydroxyphenols,which are excreted rapidly inurine. About one-third of the retained benzeneis excreted as phenols in the urine. Theremaining two-thirds may be further degradedand attached onto the tissue or oxidized andexhaled as CO2.
Kalf and associates (1989) have investigatedthe action of prostaglandin H synthasein benzene toxicity and preventionof benzene-induced myelo- and genotoxicityby nonsteroidal anti-inflammatory drugs(NSAIDs). Indomethacin, a prostaglandin Hsynthase inhibitor prevented the dose- dependentbone marrow depression and increase in marrow prostaglandin E level in mice intravenouslydosed with benzene. Indomethacin,aspirin, or meclofenamate prevented thedecrease in cellularity and increase in micronucleatedpolychromatic erythrocytes in peripheralblood, caused by intravenous injectionof benzene (100–1000 mg/kg) in mice. | | 燃焼性と爆発性 | Benzene is a highly flammable liquid (NFPA rating = 3), and its vapors may travel a
considerable distance to a source of ignition and "flash back." Vapor-air mixtures are
explosive above the flash point. Carbon dioxide and dry chemical extinguishers
should be used to fight benzene fires. | | 化学反応性 | Reactivity with Water No reaction; Reactivity with Common Materials: No reactions; Stability During Transport: Stable; Neutralizing Agents for Acids and Caustics: Not pertinent; Polymerization: Not pertinent; Inhibitor of Polymerization: Not pertinent. | | 工業用途 | Benzene (C6H6, CAS No. 71-43-2) is an aromatic hydrocarbon compound used extensively in the chemical industry as an intermediate in the manufacture of polymers and other products. It is also a common atmospheric contaminant and is present in motor vehicle exhaust emissions and cigarette smoke.
In 1990, it was discovered by the USA soft drinks industry that benzene could be produced at low levels in certain soft drinks containing a benzoate preservative and ascorbic acid. Since benzene is a known human carcinogen, its presence in food and beverages is clearly undesirable. | | Biochem/physiol Actions | Environmental carcinogen; hematoxin that is linked to increased incidence of leukemia in humans. | | 安全性プロファイル | Confirmed human carcinogen producing myeloid leukemia, Hodgkin's dsease, and lymphomas by inhalation. Experimental carcinogenic, neoplastigenic, and tumorigenic data. A human poison by inhalation. An experimental poison by skin contact, intraperitoneal, intravenous, and possibly other routes. Moderately toxic by ingestion and subcutaneous routes. A severe eye and moderate sktn irritant. Human systemic effects by inhalation and ingestion: blood changes, increased body temperature. Experimental teratogenic and reproductive effects. Human mutation data reported. A narcotic. In industry, inhalation is the primary route of chronic benzene poisoning. Poisoning by skin contact has been reported. Recent (1 987) research indicates that effects are seen at less than 1 ppm. Exposures needed to be reduced to 0.1 ppm before no toxic effects were observed. Elimination is chiefly through the lungs. | | 職業ばく露 | Benzene is used as a constituent in
motor fuels; as a solvent for fats; inks, oils, paints, plastics,
and rubber, in the extraction of oils from seeds and
nuts; in photogravure printing. It is also used as a chemical
intermediate. By alkylation, chlorination, nitration, and
sulfonation, chemicals, such as styrene, phenols, and
malefic anhydride are produced. Benzene is also used in
the manufacture of detergents, explosives, pharmaceuticals;
in the manufacture of cyclohexane and ethylbenzene;
and dye-stuffs. Increased concern for benzene as a significant
environmental pollutant arises from public exposure
to the presence of benzene in gasoline and the increased
content in gasoline due to requirements for unleaded fuels
for automobiles equipped with catalytic exhaust
converters. | | 応急処置 | Eyes, skin, respiratory system, blood, central nervous system, bone marrow. Cancer site: leukemia. | | 発がん性 | Benzene is known to be a human carcinogen based on sufficient evidence of carcinogenicity from studies in humans. | | 環境運命予測 | Benzene is released to air primarily by vaporization and combustion emissions associated with its use in gasoline. Other sources are vapors from its production and use in manufacturing other chemicals. In addition, benzene may be in industrial effluents discharged into water and accidental releases from gas and oil production, refining and distribution industries. Benzene released to soil will either evaporate very quickly or leach to groundwater. It can be biodegraded by soil and groundwater microbes. Benzene released to surface water should mostly evaporate within a few hours to a few days, depending on quantity, temperature, water turbulence, etc. Although benzene does not degrade by hydrolysis, it may be biodegraded by microbes. | | 貯蔵 | work with benzene
should be conducted in a fume hood to prevent exposure by inhalation, and splash
goggles and impermeable gloves should be worn at all times to prevent eye and skin
contact. Benzene should be used only in areas free of ignition sources. | | 輸送方法 | UN1114 Benzene, Hazard Class: 3; Labels: 3—
Flammable liquid | | 純化方法 | For most purposes, *benzene can be purified sufficiently by shaking with conc H2SO4 until free from thiophene, then with H2O, dilute NaOH and water, followed by drying (with P2O5, sodium, LiAlH4, CaH2, 4X Linde molecular sieve, or CaSO4, or by passage through a column of silica gel, and for a preliminary drying, CaCl2 is suitable), and distillation. A further purification step to remove thiophene, acetic acid and propionic acid, is crystallisation by partial freezing. The usual contaminants in dry thiophene-free *benzene are non-benzenoid hydrocarbons such as cyclohexane, methylcyclohexane, and heptanes, together with naphthenic hydrocarbons and traces of toluene. Carbonyl-containing impurities can be removed by percolation through a Celite column impregnated with 2,4-dinitrophenylhydrazine, phosphoric acid and H2O. (Prepared by dissolving 0.5g DNPH in 6mL of 85% H3PO4 by grinding together, then adding and mixing 4mL of distilled H2O and 10g Celite.) [Schwartz & Parker Anal Chem 33 1396 1961.] *Benzene has been freed from thiophene by refluxing with 10% (w/v) of Raney nickel for 15minutes, after which the nickel is removed by filtration or centrifugation. Dry *benzene is obtained by doubly distilling high purity *benzene from a solution containing the blue ketyl formed by the reaction of sodium-potassium alloy with a small amount of benzophenone. Thiophene has been removed from *benzene (absence of bluish-green coloration when 3mL of *benzene is shaken with a solution of 10mg of isatin in 10mL of conc H2SO4) by refluxing the *benzene (1.25L) for several hours with 40g HgO (freshly precipitated) dissolved in 40mL glacial acetic acid and 300mL of water. The precipitate is filtered off, the aqueous phase is removed and the *benzene is washed twice with H2O, dried and distilled. Alternatively, *benzene dried with CaCl2 has been shaken vigorously for 0.5hour with anhydrous AlCl3 (12g/L) at 25-35o, then decanted, washed with 10% NaOH, and water, dried and distilled. The process is repeated, giving thiophene-free *benzene. [Holmes & Beeman Ind Eng Chem 26 172 1934.] After shaking successively for about an hour with conc H2SO4, distilled water (twice), 6M NaOH, and distilled water (twice), *benzene is distilled through a 3-ft glass column to remove most of the water. Absolute EtOH is added and the *benzene-alcohol azeotrope is distilled. (This low-boiling distillation leaves any non-azeotrope-forming impurities behind.) The middle fraction is shaken with distilled water to remove EtOH, and again redistilled. Final slow and very careful fractional distillation from sodium, then LiAlH4 under N2, removed traces of water and peroxides. [Peebles et al. J Am Chem Soc 82 2780 1960.] *Benzene liquid and vapour are very TOXIC and HIGHLY FLAMMABLE, and all operations should be carried out in an efficient fume cupboard and in the absence of naked flames in the vicinity. [Beilstein 5 H 175, 5 I 95, 5 II 119, 5 III 469.] Rapid purification: To dry benzene, alumina, CaH2 or 4A molecular sieves (3% w/v) may be used (dry for 6hours). Then benzene is distilled, discarding the first 5% of distillate, and stored over molecular sieves (3A, 4A) or Na wire. | | Toxicity evaluation | Benzene enters the air, water, and soil as a result of industrial
processes, emissions from burning coal and oil, tobacco
smoke, gasoline exhaust, and gasoline leaks, and from natural
sources, including volcanoes and forest fires. Benzene in the
atmosphere chemically degrades in only a few days. Benzene
released to soil or waterways is subject to volatilization,
photooxidation, and biodegradation. Benzene has a short halflife
in surface water because it is so volatile. | | 不和合性 | Incompatible with oxidizers (chlorates,
nitrates, peroxides, permanganates, perchlorates, chlorine,
bromine, fluorine, etc.); contact may cause fires or explosions.
Keep away from alkaline materials, strong bases,
strong acids, oxoacids, epoxides, many fluorides and perchlorates,
nitric acid. | | 廃棄物の処理 | Dissolve or mix the material
with a combustible solvent and burn in a chemical incinerator
equipped with an afterburner and scrubber. All federal,
state, and local environmental regulations must be
observed. Dilution with alcohol or acetone to minimize
smoke is recommended. Bacterial degradation is also
possible. | | 法令条例 | Current USA and EU legislation does not set maximum limits for benzene in soft drinks. However, the FDA has adopted the Environmental Protection Agency (EPA) maximum contaminant level (MCL) for drinking water of 5 ppb as a quality standard for bottled water. ThisMCL has been used to evaluate the significance of benzene contamination in the soft drinks tested in surveys. The FSA has used the World Health Organization (WHO) guideline level for benzene in water of 10 mg kg-1 as a point of reference for its own survey results. |
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