テトラエチルプルンバン 化学特性,用途語,生産方法
解説
テトラエチルプルンバン．テトラエチル鉛，四エチル鉛などともいう．鉛-ナトリウム合金に臭化エチルを作用させるか，塩化鉛(Ⅱ)に臭化エチルマグネシウムを作用させて合成する．特有の芳香を有する無色の液体．沸点83 ℃(～1.8 kPa)，凝固点－135 ℃．d4201.6528．nD201.5198．有機溶媒に可溶，水に不溶．室温で徐々に分解し，125 ℃ 以上に加熱すると急速に分解する．毒性が強く，吸入すると中毒症状を起こす．かつて自動車用および航空機用ガソリンのアンチノック剤として用いられた．
用途
オクタン価向上剤
化学的特性
colourless to yellow liquid
物理的性質
Colorless liquid; burns with orange flame with green margin; refractive index 1.5198; density 1.653 g/mL at 20°C; insoluble in water; slightly soluble in ethanol; soluble in benzene, toluene, gasoline, and petroleum ether.
使用
Tetraethyllead is used as an additive to gasolineto prevent knocking in motors. However,because of its high toxicity and the pollutionproblem, its use in gasoline has been drasticallycurtailed.
調製方法
These compounds were, at one time, the major industrial use
of lead and source of environmental pollution of inorganic
lead combustion products. However, the addition of these
compounds to gasoline in the major industrialized countries
of the world has been discontinued because of the use of
catalysts for the control of the amount of nitrogen oxides in
automobile exhaust. Organolead additives are still being
phased out in many underdeveloped countries, although
the United Nations has called for a global phaseout of
lead in gasoline.
定義
ChEBI: An organolead compound consisting of four ethyl groups joined to a central lead atom.
製造方法
Lead tetraethyl is prepared by heating ethyl chloride in the presence of a catalyst in an autoclave at 40 to 60°C with an alloy of lead and sodium:
Pb + 4Na + 4C
2H
5Cl → Pb(C
2H
5)
4 + 4NaCl
Also, it can be prepared by the reaction of lead with ethylene and hydrogen in the presence of Ziegler catalyst, triethylaluminum:
Pb + 4C
2H
4 + 2H
2 → Pb(C
2H
5)
4
一般的な説明
A colorless liquid with a characteristic odor. Flash point 200°F. Density 14 lb / gal. Insoluble in water. Toxic by inhalation and by skin absorption.
空気と水の反応
Insoluble in water.
反応プロフィール
TETRAETHYL LEAD decomposes under UV light. Reacts with fats; reacts violently with oxidizing agents, causing fire and explosion hazards. Attacks rubber [Handling Chemicals Safely 1980. p. 890].
危険性
Toxic by ingestion, inhalation, and skin
absorption. Central nervous system impairment.
Questionable carcinogen.
健康ハザード
Extremely poisonous; may be fatal if inhaled, swallowed, or absorbed from the skin. Contact may cause burns to skin and eyes. Most symptoms of poisoning are due to the effects of tetraethyllead on the nervous system.
火災危険
May explode in fires. Decomposes slowly at room temperature and more rapidly at elevated temperatures.
化学性质
炭素-金属結合が弱く反応性が高い（Pb-C結合エネルギー：130 kJ mol?1）。アリールトリアセトキシ鉛（Ⅳ）類は，形式的に芳香族カチオン等価体として作用し，塩基存在下，β-ジカルボニル化合物などの求核剤とカップリングする。テトラアルキル体でも，ルイス酸の存在下でアルデヒドなどと反応する。テトラアルキル鉛は空気や水には安定であり100℃までは熱に対して安定であるが，高温ではフリーラジカルと単体金属を生成する。
安全性プロファイル
Human poison by an unspecified route. Experimental poison by ingestion, intraperitoneal, intravenous, subcutaneous, and parented routes. Moderately toxic by inhalation and skin contact. Experimental teratogenic and reproductive effects. Questionable carcinogen with experimental carcinogenic data. Mutation data reported. Lead compounds are particularly toxic to the central nervous system. It is a solvent for fatty materials and has some solvent action on rubber as well. The fact that it is a lipoid solvent makes it an industrial hazard because it can cause intoxication not only by inhalation but also by absorption through the skin. Decomposes when exposed to sunlight or allowed to evaporate; forms triethyl lead, which is also a poisonous compound, as one of its decomposition products. May cause elemental lead intoxication by coming in contact with the skin. A combustible liquid when exposed to heat, flame, or oxidizers. Can react vigorously with oxidzing materials. Exposure to air for several days may cause explosive decomposition. To fight fire, use dry chemical, CO2, mist, foam. When heated to decomposition it emits toxic fumes of Pb. See also LEAD COMPOUNDS.
職業ばく露
Tetraethyl lead is used as a component of antiknock mixes for gas and as an intermediate in making fungicides; Tetraethyl lead (used as an antiknock compound in gasoline) can also contains impurities, such as ethylene dibromide and ethylene dichloride.
発がん性
A case-control study of former workers in a TEL-producing
plant found a strong association between exposure to the TEL
manufacturing process and rectal cancer (the odds ratio was
3.7 with 90% confidence limits of 1.3–10.2 for the analysis of
ever/never exposed to TEL). An exposure–response relationship
was noted with a fourfold elevation in the odds ratio at
the high–very high cumulative exposure level. Similar results
were obtained for cancers of the sigmoid colon. These results
suggest to the authors that exposure to the TEL manufacturing
process may have played a causal role in the colorectal
cancer findings in this plant. However, IARC in 2006
has included organolead compounds (TEL and TML), with
Lead and its Compounds in Group 3, not classifiable as to its
carcinogenicity to humans.
合成方法
塩化アルキル（RCl）をオートクレーブ中でNa-Pb合金と直接反応させる。4RCl ＋ 4Na-Pb → RPb ＋ 3Pb ＋ 4NaCl
輸送方法
UN1649 Motor fuel antiknock mixtures, Hazard Class: 6.1; Labels: 6.1-Poisonous materials.
純化方法
Its more volatile contaminants can be removed by exposure to a low pressure (by continuous pumping) for 1hour at 0o. Purify it by stirring with an equal volume of H2SO4 (d 1.40), keeping the temperature below 30o, repeating this process until the acid layer is colourless. It is then washed with dilute Na2CO3 and distilled water, dried with CaCl2 and fractionally distilled at low pressure under H2 or N2 [Calingaert Chem Rev 2 43 1926]. It prevents “knocking” in petrol combustion engines. [Milde & Beatty Adv Chem Res 23 306-318 1959, Beilstein 4 H 639.] VERY POISONOUS.
不和合性
Vapors may form explosive mixture with air. A strong reducing agent. Violent reaction with strong oxidizers, sulfuryl chloride; halogens, oils and fats; rust, potassium permanganate. Decomposes slowly in light and at room temperature, and more rapidly at temperatures above 110C. Attacks rubber and some plastics and coatings.
廃棄物の処理
Consult with environmental regulatory agencies for guidance on acceptable disposal practices. Generators of waste containing this contaminant (≥ 100 kg/mo) must conform with EPA regulations governing storage, transportation, treatment, and waste disposal. Controlled incineration with scrubbing for collection of lead oxides which may be recycled or land filled. It is also possible to recover alkyl lead compound from wastewaters as an alternative to disposal.
テトラエチルプルンバン 上流と下流の製品情報
原材料
準備製品