Тетрафторид углерода

Описание

Tetrafluoromethane, CF4, also known as carbon tetrafluoride and fluorocarbon 14, is a colorless gas that is slightly soluble in water.

Химические свойства

colourless gas

Использование

Low tempereture refrigerant; gaseous insulator.

Общее описание

Tetrafluoromethane is a colorless nonflammable gas. Carbon tetrafluoride is shipped as a liquid under pressure. Carbon tetrafluoride may be narcotic at high concentrations. Under prolonged exposure to fire or heat the containers may rupture violently and rocket. Carbon tetrafluoride is used as a refrigerant.

Профиль реактивности

The reaction of aluminum with various halogenated hydrocarbons produces a self-sustaining reaction with sufficient heat to melt aluminum pieces, examples of other halogenated hydrocarbons are fluorotrichloromethane, dichlorodifluoromethane, chlorodifluoromethane, tetrafluoromethane. The vigor of the reaction appears to be dependent on the combined degree of fluorination and the vapor pressure [Chem. Eng. News 39(27):44. 1961].

Опасность

Toxic by inhalation.

Угроза здоровью

Vapors may cause dizziness or asphyxiation without warning. Vapors from liquefied gas are initially heavier than air and spread along ground. Contact with gas or liquefied gas may cause burns, severe injury and/or frostbite. Fire may produce irritating, corrosive and/or toxic gases.

Пожароопасность

Some may burn but none ignite readily. Containers may explode when heated. Ruptured cylinders may rocket.

Профиль безопасности

Mddly toxic by inhalation. Less chronically toxic than carbon tetrachloride. Violent reaction with Al. When heated to decomposition it emits toxic fumes of F-. See also FLUORIDES.

Возможный контакт

Tetrafluoromethane is used in fire extinguishers and as a low temperature refrigerant.

Перевозки

UN1982 Tetrafluoromethane, compressed or or Refrigerant gas R14, Hazard Class: 2.2; Labels: 2.2Nonflammable gas. Cylinders must be transported in a secure upright position, in a well-ventilated truck. Protect cylinder and labels from physical damage. The owner of the compressed gas cylinder is the only entity allowed by federal law (49CFR) to transport and refill them. It is a violation of transportation regulations to refill compressed gas cylinders without the express written permission of the owner.

Методы очистки

Purify CF4 by repeated passage over activated charcoal at solid-CO2 temperatures. Traces of air are removed by evacuating while alternately freezing and melting. Alternatively, liquefy CF4 by cooling in liquid air and then fractionally distil it under vacuum. (The chief impurity originally present is probably CF3Cl). Use brass equipment. It is non-flammable. [Beilstein 1 H 59, 1 I 8, 1 II 11, 1 III 35, 1 IV 26.]

Несовместимости

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. Forms hydrogen fluoride and fluorides on decomposition with hot surfaces above 125F/52C or open flame. Incompatible with powdered metals; including aluminum, zinc, and beryllium.

Утилизация отходов

Return refillable compressed gas cylinders to supplier. Nonrefillable cylinders should be disposed of in accordance with local, state and federalregulations. Allow remaining gas to vent slowly into atmosphere in an unconfined area or exhaust hood. Refillabletype cylinders should be returned to original supplier with any valve caps and outlet plugs secured and valve protection caps in place.