Propyne

Description

Methyl acetylene is a flammable, colorless gas with a sweet odor. Molecular weight= 40.07;Boiling point=23.3℃; Freezing/Melting point=102.8℃; Vapor pressure= 5.2 atm; Relative vapor density (air= 1)= 1.41. Explosive limits: LEL= 1.7%; UEL= 11.7%. Hazard Identification (based on NFPA-704 M Rating System): Health 2, Flammability 4, Reactivity 2. A fuel that is shipped as a liquefied compressed gas. Practically insoluble in water; solubility 0.4%.

Chemical properties

Colorless, liquefied gas.

Chemical properties

Methyl acetylene is a flammable, colorless gas. Sweet odor. A fuel that is shipped as a liquefied compressed gas.

Chemical properties

Propyne,C3H4, is a colorless, highly flammable, and explosive gas. Sources of propyne emissions to the atmosphere include automobile and turbine exhaust, biomass and polymer combustion, petroleum manufacturing, and tobacco smoke.

The Uses of Propyne

Propellant; welding

The Uses of Propyne

Specialty fuel, chemical intermediate.

The Uses of Propyne

Propyne is produced by thermal or catalytic pyrolysis of propene. Like acetylene, propyne is used as a welding torch fuel, as a specialty fuel, and chemical intermediate.

Definition

ChEBI: Propyne is an alkyne, a terminal acetylenic compound and a gas molecular entity.

General Description

A colorless liquefied gas with a sweet odor. Mp: -104°C, bp: -23.1°C. Insoluble in water, soluble in ethanol, chloroform and benzene. Moderately toxic by inhalation. Used as a speciality fuel. Denser than air. Vapors may ignite at distant sources of ignition and flash back.

Air & Water Reactions

Highly flammable. PEROXIDE FORMING WHICH LEADS TO EXPLOSIONS

Reactivity Profile

Propyne is highly flammable. The liquid material in cylinders contains about 30% propadiene. Detonation may occur at 95° C [MCA Case History No. 632]. Reacts exothermically with many oxidizing agents and with some reducing agents as well. May react with silver, copper, and mercury salts in aqueous solution to give explosive acetylides. Incompatible with brass that contains more than 65% copper, with other copper-containing alloys, with Monel metal, with neoprene, polyethylene, and, to a lesser extent, with Teflon. May enflame in air in the presence of Co, Hg, Hg salts, K, Ag, Ag salts, RbH, CsH, halogens, HNO3, NaH. Can decompose explosively when compressed to 4.5 to 5.6 atmospheres. Moderate explosion hazard when exposed to heat or flame or by spontaneous chemical reaction. Has been known to decompose explosively at high pressures and moderate temperatures in the absence of air.

Hazard

Flammable, dangerous fire risk. Toxic by inhalation. Central nervous system impairment.

Health Hazard

At high concentrations methyl acetylene causes narcosis in animals, and it is expected that severe exposure will produce the same effect in humans.

Safety Profile

Ths compound is a simple anesthetic and in high concentration is an asphyxiant. Mutation data reported. Dangerous fire hazard when exposed to heat or flame; can react vigorously with oxibzing materials. Explosive in the form of vapor when exposed to heat or flame. Localized heating of liquid-containing cylinders to 95°C may cause an explosion. Product of reaction with silver nitrate ignites at 150°C. A commercial mixture containing 30% propyne in MAPP gas is similar to ethylene in potential hazards and handling requirements. To fight fire, stop flow of gas. When heated to decomposition it emits acrid smoke and irritating fumes. See also ACETYLENE COMPOUNDS.

Potential Exposure

This material may be used as a liquid rocket propellant, in admixture with propadiene as an industrial cutting fuel.

First aid

If this chemical gets into the eyes, remove any contact lenses at once and irrigate immediately for at least 15 min, occasionally lifting upper and lower lids. Seek medical attention immediately. If this chemical contacts the skin, remove contaminated clothing and wash immediately with soap and water. Seek medical attention immediately. If this chemical has been inhaled, remove from exposure, begin rescue breathing (using universal precautions, including resuscitation mask) if breathing has stopped and CPR if heart action has stopped. Transfer promptly to a medical facility. When this chemical has been swallowed, get medical attention. Give large quantities of water and induce vomiting. Do not make an unconscious person vomit. Medical observation is recommended for 2448 h after breathing overexposure, as pulmonary edema may be delayed. As first aid for pulmonary edema, a doctor or authorized paramedic may consider administering a corticosteroid spray. If frostbite has occurred, seek medical attention immediately; do NOT rub the affected areas or flush them with water. In order to prevent further tissue damage, do NOT attempt to remove frozen clothing from frostbitten areas. If frostbite has NOT occurred, immediately and thoroughly wash contaminated skin with soap and water.

Environmental Fate

Chemical/Physical. When passed through a cold solution containing hydrobromite ions, 1-bromo-1-propyne was formed (Hatch and Kidwell, 1954).
Combustion products include carbon monoxide, carbon dioxide, and water vapor.

storage

Color Code—Red Stripe: Flammability Hazard: Store separately from all other flammable materials. May form peroxides in storage. Prior to working with this chemical you should be trained on its proper handling and storage. Before entering confined space where this chemical may be present, check to make sure that an explosive concentration does not exist. Store in tightly closed containers in a cool, well-ventilated area away from oxidizers. Where possible, automatically pump liquid from drums or other storage containers to process containers. Sources of ignition, such as smoking and open flames, are prohibited where this chemical is used, handled, or stored in a manner that could create a potential fire or explosion hazard. Wherever this chemical is used, handled, manufactured, or stored, use explosion-proof electrical equipment and fittings. Procedures for the handling, use and storage of cylinders should be in compliance with OSHA 1910.101 and 1910.169, as with the recommendations of the Compressed Gas Association.

Shipping

UN3161 Liquefied gas, flammable, n.o.s., Hazard Class: 2.1; Labels: 2.1-Flammable gas, Technical Name Required. 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.

Purification Methods

Purify it by preparative gas chromatography. [Beilstein 1 H 246.]

Incompatibilities

Forms explosive gas mixture with air. The liquid material in cylinders contains about 30% propadiene. Detonation may occur at 95C. May form explosive peroxides. Can decompose explosively on heating and @ 4.5
5.6 atmospheres of pressure. Strong oxidizers may cause fire and explosions. Forms shock sensitive compounds with copper, magnesium, silver and their alloys. Copper or copper alloys containing more than 67% copper should not be used in handling equipment. Attacks some plastics, rubber and coatings.

Waste Disposal

Return refillable compressed gas cylinders to supplier. 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.