塩化ホスホリル

外観

無色澄明の液体

性質

オキシ塩化リンの融点は1.25℃、沸点は105.8℃です。外観は、無色の発煙性液体で、刺激臭があります。蒸気は、空気よりも重いです。塩化ホスホリルやリン酸トリクロリドとも呼ばれています。分子式はPOCl₃で、モル質量は153.33g/molです。

オキシ塩化リンはリンを中心とする四面体型構造の化学物質です。P-Cl結合を3つとP=O結合を1つ有しています。P=O結合は非常に強く、結合解離エネルギーは533.5kJ/molです。ショーメーカー・スチーブンソン則 (英: Schomaker-Stevenson rule) によって、結合強度や電気陰性度からも、フッ化ホスホリル (POF₃) と比べて二重結合の寄与がかなり大きいことがわかっています。

オキシ塩化リンのP=O結合は、ケトンのカルボニル基のπ結合とは違います。P-Clのσ*軌道にO原子の孤立電子対が供与されることで、P-Oのπ結合が生じるようです。ただし、P-O間の相互作用は、未だに長い間論争が続いています。

溶解性

水と激しく反応, 四塩化炭素, 二硫化炭素には易溶。水又はエタノールによって発熱して分解する。ベンゼンに溶けやすい。

反応

のようなルイス酸とともに、過剰のとオキシ塩化リンを加熱すると、トリアリールリン酸エステルを得ることが可能です。

オキシ塩化リンは、ルイス塩基としても働きます。例えば、四塩化チタンなどのルイス酸と反応すると、付加物を生成します。

オキシ塩化リンとの付加物は安定であり、フリーデル・クラフツ反応 (英: Friedel–Crafts reaction) の後の混合物からでも、塩化アルミニウムを完全に除去可能です。塩化アルミニウムの存在下で、オキシ塩化リンはと反応して、POBr₃を生じます。

解説

POCl3(153.33)．りんトリクロリドオキシド, 三塩化ホスホリルともいう．俗称はオキシ塩化リン．無色の発煙性液体．分子はPを中心とする四面体型構造．P-O1.449 Å，P-Cl1.993 Å．∠Cl-P-Cl103.3°．融点2 ℃，沸点105.3 ℃．密度1.65 g cm－3(25 ℃)．水により加水分解し，HClとリン酸を生成する．金属ハロゲン化物に配位して錯体をつくる．ZrCl4，HfCl4はともにPOCl3と錯体をつくり，分留して両元素を分離しうる．また，フリーデル-クラフツ反応後の余分のAlCl3触媒を，このPOCl3と錯体を形成させて分離除去することができる．塩化ホスホリルは，有機化合物の塩素化剤，触媒，冷媒などに用いられる．特有臭があり，皮膚，眼，粘膜などをおかす．有毒．[CAS 10025-87-3]森北出版「化学辞典（第2版）

用途

可塑剤(リン酸トリクレジル)の製造、医薬(サルファ剤、ビタミンB1など)の製造、香料、不燃性フィルム原料、ウラン鉱抽出剤、有機合成における塩素置換剤及び触媒、無水酢酸、リン系農薬製造用

使用上の注意

不活性ガス封入

化学的特性

Phosphorus oxychloride is a clear, colorless to yellow, fuming, oily liquid with a pungent and musty odor.

物理的性質

Colorless fuming liquid with a pungent odor; density 1.645 g/mL; freezes at 1°C; boils at 105.5°C; reacts with water and ethanol.

使用

Phosphorus oxychloride is an important intermediate in the production of triarylphosphate esters (e.g., triphenyl phosphate and tricresyl phosphate), which have been used as flame retardants and plasticizers for PVC. It is acutely toxic to the eyes, throat, and respiratory tract. Phosphorus oxychloride is also used in nuclear reprocessing, as chlorinating agent, especially to replace oxygen in organic compounds, as solvent in cryoscopy and the semiconductor industry.

製造方法

Phosphorus oxychloride can be prepared from phosphorus trichloride or phosphorus pentachloride. It can be obtained from phosphorus trichloride by cautious addition of potassium chlorate:
3PCl₃ + KClO₃ → 3POCl₃ + KCl
The oxychloride also is obtained by the action of boric acid or oxalic acid with phosphorus pentachloride:
3PCl₅ + 2B(OH）₃ → 3POCl₃ + B₂O₃ + 6HCl
PCl₅ + (COOH）₂ → POCl₃ + CO + CO₂ + 2HCl
Phosphorus oxychloride also is made by heating calcium phosphate in a current of chlorine and carbon monoxide at 350°C:
2Ca₃(PO₄）₂ + 9Cl₂ + 6CO → 4POCl₃ + 6CaCO₃
Alternatively, heating a mixture of calcium phosphate and carbon in a current of chlorine at 750°C yields the oxychloride.

定義

A white crystalline solid. It is a monobasic acid forming the anion H₂PO₂ – in water. The sodium salt, and hence the acid, can be prepared by heating yellow phosphorus with sodium hydroxide solution. The free acid and its salts are powerful reducing agents.

一般的な説明

A colorless fuming liquid with a pungent odor. Density 14.0 lb / gal. Very toxic by inhalation and corrosive to metals and tissue. Used in gasoline additives and hydraulic fluids.

反応プロフィール

Phosphorus oxychloride is water reactive. Incompatible with strong oxidizing agents, alcohols, bases (including amines). May react vigorously or explosively if mixed with diisopropyl ether or other ethers in the presence of trace amounts of metal salts [J. Haz. Mat., 1981, 4, 291]. Combining the chloride with zinc dust caused immediate ignition, due to the formation of phosphine gas which ignites, [Mellor, 1940, Vol. 8, 1025]. An exotherm starting with the mixing of Phosphorus oxychloride with acetone (a ketone) lead to an explosion, may behave similarly with other ketones, [Organic Process Research and Development, Vol.4, No. 6,200, "Phosphorus oxychloride and Acetone: An Incompatibility Investigation Using ARC."]

危険性

The compound is highly irritating to skin, eyes and mucous membranes. Inhaling its vapors can cause pulmonary edema.

健康ハザード

Inhalation of vapors of phosphorus oxychloride produced acute and chronic toxicity in test subjects. In humans, exposure to its vapors may cause headache, dizziness, weakness, nausea, vomiting, coughing, chest pain, bronchitis, and pulmonary edema. Most of these symptoms are manifested from chronic exposure to its vapors.
LC50 value, inhalation (rats): 48 ppm (301 mg/m³)/4 h
Vapors of this compound are an irritant to the eyes and mucous membranes. The liquidis corrosive and can cause skin burns. An oral LD50 value for rats is documented to be 380 mg/kg (NIOSH 1986)..

火災危険

Poisonous, corrosive, and irritating gases are generated when Phosphorus oxychloride is heated or is in contact with water. Phosphorus oxychloride may ignite other combustible materials (wood, paper, oil, etc.). Phosphorus oxychloride reacts violently with water. When heated to decomposition, Phosphorus oxychloride emits toxic fumes of chlorides and oxides of phosphorus; Phosphorus oxychloride will react with water or steam to produce heat and toxic and corrosive fumes. Incompatible with carbon disulfide; N,N-dimethylformamide; 2,5-dimethylpyrrole; 2,6-dimethyl- pyridine N-oxide; dimethylsulfoxide; Ferrocene-1,1-dicarboxylic acid; water; and zinc. Do not store with combustible materials, particularly fibrous organic materials, or with electrical or other equipment that can be corroded. Reacts violently with moisture.

使用用途

オキシ塩化リンは、油圧用作動液、可塑剤 (リン酸トリクレジル) 、ガソリン添加剤、防火剤の製造に使用されます。また、医薬 (サルファ剤、ボタミンB1など) の「製造」「染料」「リン系農薬」「香料」「不燃性フィルムの原料」「ウラン鉱抽出剤」などにも利用可能です。その他、半導体製造工程では拡散剤としても使われています。

オキシ塩化リンは、劇物取締法により毒物に指定されており、眼、鼻、喉などの呼吸器および中枢神経系に対する刺激性があるので取扱いに注意が必要です。

安全性プロファイル

Poison by inhalation and ingestion. A corrosive eye, skin, and mucous membrane irritant. Potentially explosive reaction with water evolves hydrogen chloride and phosphine, which then ignites. Explosive reaction with 2,6dimethylpyridine N-oxide, dimethyl sulfoxide, ferrocene1 ,l'-dicarboxylic acid, pyridne N-oxide (above bO'C), sodmm + heat. Violent reaction or ignition with BI3, carbon disulfide, 2,5-dimethyl pyrrole + dimethyl formamide, organic matter, zinc powder. Reacts with water or steam to produce heat and toxic and corrosive fumes. Incompatible with carbon disulfide, N,Ndimethyl-formamide, 2,5-dunethylpyrrole, 2,6-dimethylpyridine N-oxide, dimethylsulfoxide, ferrocene1 ,I-dicarboxylic acid, water, zinc. When heated to decomposition it emits highly toxic fumes of Cland POx

職業ばく露

Phosphorus oxychloride is used in the manufacture of pesticides, pharmaceuticals, plasticizers, gasoline additives; and hydraulic fluids.

輸送方法

UN1810 Phosphorus oxychloride, Hazard class: 6.1; Labels: 6.1-Poisonous materials, 8-Corrosive material, Hazard Zone B.

純化方法

Distil the liquid under reduced pressure to separate it from the bulk of the HCl and the phosphoric acid (from hydrolysis); the middle fraction is re-distilled into ampoules containing a little purified mercury. These ampoules are sealed and stored in the dark for 4-6weeks with occasional shaking to facilitate reaction of any free chloride with the mercury. The POCl3 is then again fractionally distilled and stored in sealed ampoules in the dark until required [Herber J Am Chem Soc 82 792 1960]. Lewis and Sowerby [J Chem Soc 336 1957] refluxed their distilled POCl3 with Na wire for 4hours, then removed the Na and again distilled. Use Na only with almost pure POCl3 to avoid explosions. HARMFUL VAPOURS; work in an efficient fume cupboard.

不和合性

A powerful oxidizer. Violently decomposes in water, forming heat and hydrochloric and phosphoric acids. Violent reaction with alcohols, phenols, amines, reducing agents; combustible materials; carbon disulfide; dimethylformamide, and many other many materials. Rapid corrosion of metals, except nickel and lead.

廃棄物の処理

Pour onto sodium bicarbonate. Spray with aqueous ammonia and add crushed ice. Neutralize and pour into drain with running water. In accordance with 40CFR165, follow recommendations for the disposal of pesticides and pesticide containers. Must be disposed properly by following package label directions or by contacting your local or federal environmental control agency, or by contacting your regional EPA office.