Калия перхлорат

Химические свойства

Potassium perchlorate occurs as a colorless crystal or crystalline powder. It decomposes at 400℃ and may also decompose by organic matter, oxidizable substances and on concussion. Potassium perchlorate is soluble in 65 parts cold water, 15 parts boiling water and is practically insoluble in alcohol.

Физические свойства

Colorless crystals or white crystalline powder; rhombohedral structure;density 2.52 g/cm₃; melts around 610°C under controlled conditions; decomposes at 400°C; slightly soluble in cold water 0.75 g/100mL at 0°C, soluble in boiling water, 21.8 g/100mL at 100°C; practically insoluble in alcohol; insoluble in ether.

Использование

Potassium perchlorate is used in ammunition percussion caps, explosive primers, fireworks and propellants. It acts as a solid rocket propellant. It is also used as an oxidizer in colored pyrotechnic compositions and flash powder. It is used as an antithyroid and involved in the treatment of hyperthyroidism. The mixture of anthracene and sulfur with potassium perchlorate is used for generating black smoke signaling.

Подготовка

The potassium perchlorate can be separated from the potassium chloride because it is less soluble in water; however, the preferred production route involves anodic oxidation of cold chloride solutions using a high voltage and high current density. The alkali perchlorates can also be prepared by neutralizing perchloric acid with alkali carbonates, or by metathesis between ammonium perchlorate and alkali sulphates.

Показания

The perchlorate ion of potassium perchlorate, KClO₄, is a competitive inhibitor of thyroidal I^- transport via the Sodium Iodide Symporter (NIS).This drug can cause fatal aplastic anemia and gastric ulcers and is now rarely used. If administered with careful supervision, in limited low doses and for only brief periods, serious toxic effects can be avoided. The compound is especially effective in treating iodine-induced hyperthyroidism, which may occur, for example, in patients treated with the antiarrhythmic compound amiodarone. Perchlorate ion can also be used in a diagnostic test of I^- incorporation into Tg, the so-called perchlorate discharge test.

Общее описание

A white crystalline solid. Forms explosive mixtures wilh certain combustible materials. Difficult to burn, but will accelerate burning of combustible materials. Prolonged exposure to fire or heat may result in an explosion. Used in explosives, pyrotechnics, photography.

Реакции воздуха и воды

Slight solubility in water (7.55 mg /mL of cold water).

Профиль реактивности

Potassium perchlorate is a strong oxidizing agent. Explosively decomposes at or over 400°C. Decomposed by organic matter (reducible material) and on concussion [Merck 11th ed. 1989]. Mixture with powdered magnesium is a friction-sensitive explosive [Safety Eng. Reports 1947]. Incompatible with reducing agents, such as: metal powders aluminum, titanium, barium, magnesium, nickel, and various metal hydrides, sulfur.

Опасность

Fire risk in contact with organic materials, strong oxidizing agent. Strong irritant.

Угроза здоровью

Inhalation, ingestion or contact (skin, eyes) with vapors or substance may cause severe injury, burns or death. Fire may produce irritating, corrosive and/or toxic gases. Runoff from fire control or dilution water may cause pollution.

Пожароопасность

These substances will accelerate burning when involved in a fire. Some may decompose explosively when heated or involved in a fire. May explode from heat or contamination. Some will react explosively with hydrocarbons (fuels). May ignite combustibles (wood, paper, oil, clothing, etc.). Containers may explode when heated. Runoff may create fire or explosion hazard.

Профиль безопасности

An experimental teratogen. A powerful oxidizer. Severe irritant to skin, eyes, and mucous membranes. Has been implicated in aplastic anemia. Absorption can cause methemoglobinemia and hdney injury. It has been involved in many industrial explosions. Explodes on contact with aluminum + barium nitrate + potassium nitrate + water. Forms explosive mixtures with aluminum powder + titanium dioxide, ethylene glycol (240°C), cotton lint (245°C), furfural (27O°C), lactose, metal powders (e.g., aluminum, iron, magnesium, molybdenum, nickel, tantalum, titanium), sulfur, titanium hydride. Reaction with ethanol + heat forms the explosive ethyl perchlorate. Violent reaction or igmtion under the proper conditions with aluminum + aluminum fluoride, barium chromate + tungsten or titanium, boron + magnesium + silicone rubber, ferrocenium lammine- tetrahs(thiocyanat0-N) chromate(1-), potassium hexacyanocobaltate(3-), Al + Mg, charcoal, F2, Ni + Ti, reducing agents. When heated to decomposition it emits very toxic fumes of K2O and Cl-. See also PERCHLORATES.

Методы очистки

It crystallises from boiling water (5mL/g) on cooling. Dry it under vacuum at 105o.