Propylene (C3H6) is a colorless, flammable gas commonly used in the production of plastics and synthetic fibers. It is also used as fuel in welding and cutting torches.
| IUPAC name | Propene |
| Molecular formula | C3H6 |
| CAS number | 115-07-1 |
| Synonyms | Propylene, methylethylene, prop-1-ene, methyl ethylene |
| InChI | InChI=1S/C3H6/c1-3-2/h3H,1-2H3 |
Propylene Properties
Propylene Formula
The chemical formula for propylene is C3H6. This means that each molecule of propylene contains three carbon atoms and six hydrogen atoms. The formula is important in chemical reactions because it shows the number and types of atoms present in each molecule. The formula for propylene is often used in the production of plastics, synthetic fibers, and other industrial materials.
Propylene Molar Mass
Propene, also known as propene, has a molar mass of 42.08 g/mol. This means that one mole of propene molecules weighs 42.08 grams. The molar mass is important in chemical calculations because it allows us to convert between mass and moles of a substance. To calculate the molar mass of propene, we add the atomic masses of its constituent atoms: three carbon atoms, each with a mass of 12.01 amu, and six hydrogen atoms, each with a mass of 1.01 amu.
Propylene Boiling Point
The boiling point of propene is -47.6 °C (-53.7 °F). This means that at normal atmospheric pressure, propene will boil and turn into a gas at -47.6 °C. The boiling point is an important physical property of propene because it determines the conditions under which the substance will change from a liquid to a gas. The low boiling point of propene makes it useful as a refrigerant and in the production of chemicals.
Propylene Melting Point
Propene does not have a well-defined melting point because it undergoes a gradual transition from a solid to a liquid as it is heated. However, the melting range of propene is approximately -185 to -135 °C (-301 to -211 °F). This means that propene will begin to melt at around -185 °C and will be completely melted at around -135 °C. The melting point is important in determining the conditions under which propene will change from a solid to a liquid.
Propylene Density g/mL
The density of propene is 0.74 g/mL at room temperature (25 °C). This means that one milliliter of propene weighs 0.74 grams. The density is an important physical property of propene because it allows us to determine the mass of a given volume of the substance. The low density of propene makes it useful in applications where a lightweight material is required.
Propylene Molecular Weight
The molecular weight of propene is 42.08 g/mol. This value is the sum of the atomic weights of all the atoms in a single molecule of propene. Molecular weight is an important property because it allows us to calculate the amount of a substance in moles from its mass or vice versa.
Propylene Structure
Propene has a linear molecular structure, with each carbon atom bonded to two hydrogen atoms and one other carbon atom. The double bond between the two carbon atoms gives propene its reactive nature and makes it useful in a variety of industrial applications. The structure of propene is important in determining its properties, such as its boiling point and melting point.
| Appearance | Colorless gas |
| Specific Gravity | 0.97 |
| Color | Colorless |
| Odor | Faintly sweet, gasoline-like odor |
| Molar Mass | 42.08 g/mol |
| Density | 0.74 g/mL (at 25 °C) |
| Melting Point | -185 to -135 °C (-301 to -211 °F) |
| Boiling Point | -47.6 °C (-53.7 °F) |
| Flash Point | -108 °C (-162 °F) |
| Water Solubility | 0.075 g/100 mL (at 20 °C) |
| Solubility | Soluble in acetone, ethanol, ether |
| Vapour Pressure | 50.6 kPa (at 25 °C) |
| Vapour Density | 1.45 (relative to air) |
| pKa | 44 |
| pH | Not applicable (propylene is not acidic or basic) |
Propylene Safety and Hazards
Propene is generally considered a relatively safe compound to handle, but it does pose some hazards. It is highly flammable and can ignite easily, so it should be stored and handled away from sources of ignition. Contact with the skin or eyes can cause irritation, and inhalation of high concentrations of propene can cause dizziness and even unconsciousness. As with any chemical, it is important to follow proper safety procedures when handling propene, such as wearing protective equipment like gloves and goggles and ensuring adequate ventilation. In case of exposure or accidental ingestion, seek medical attention immediately.
| Hazard Symbols | Highly flammable (F+) |
| Safety Description | Keep away from sources of ignition. Use in well-ventilated areas. |
| UN IDs | UN 1077 |
| HS Code | 2901.10.00 |
| Hazard Class | 2.1 (flammable gas) |
| Packing Group | Group A |
| Toxicity | Not considered toxic |
Propylene Synthesis Methods
Various methods can synthesize propene, including steam-cracking hydrocarbons, propane dehydrogenation, and fluid catalytic cracking.
Steam cracking is the most common method of propene synthesis. This involves the heating of hydrocarbon feedstocks, such as ethane, propane, or naphtha, to high temperatures in the presence of steam. The process involves cooling and separating the resulting mixture of hydrocarbons to isolate propene as a separate product.
Propane dehydrogenation is another method of propene synthesis. This involves the reaction of propane with a catalyst to remove hydrogen and produce propene. This method is attractive because propane is readily available and inexpensive.
The process of fluid catalytic cracking utilizes a catalyst to transform heavy hydrocarbons into lighter products, including propene, by breaking down the larger molecules into smaller ones.
Propylene Uses
Propene is a versatile chemical that has many uses across a range of industries. Here are some of the most common uses of propene:
- Production of polypropylene: Plays a crucial role as a primary raw material in producing polypropylene, a versatile material utilized in various applications, such as packaging, textiles, and automotive parts.
- Fuel: Used as a fuel in many industrial applications, such as flame cutting and welding.
- Solvent: Serves as a useful solvent for a variety of chemicals and people use it in many applications, including the extraction of essential oils.
- Refrigerant: Used as a refrigerant in some systems, particularly in applications where the use of other refrigerants is restricted.
- Chemical intermediate: Used as a chemical intermediate in the production of many other chemicals, such as propylene oxide, acrylonitrile, and butyraldehyde.
- Food packaging: Used in the production of food packaging materials, such as films and containers.
- Personal care products: Many personal care products, such as moisturizers and hair care products, use propylene glycol, a derivative of propene.
Questions:
Q: Which reaction should be used to convert propene into an alkyl halide?
A: Propene can be converted into an alkyl halide using a reaction with hydrogen halides, such as hydrogen chloride (HCl) or hydrogen bromide (HBr).
Q: What is the empirical formula for propene (c3h6)?
A: The empirical formula for propene (C3H6) is CH2.
Q: Is propene soluble in water?
A: Propene is not soluble in water because it is a nonpolar compound and water is a polar solvent.
Q: What are the formula masses of propene, C3H6?
A: The formula mass of propene (C3H6) is approximately 42.08 g/mol.
Q: What is the empirical formula of the following molecular formula: C3H6?
A: The empirical formula of C3H6 is CH2.
Q: How could you show experimentally that the molecular formula of propene is C3H6, not CH2?
A: One experimental method to determine the molecular formula of propene is to analyze its combustion products. If propene is combusted in excess oxygen, the products will be carbon dioxide and water. By measuring the amounts of carbon dioxide and water produced, the molecular formula of propene can be determined to be C3H6 rather than CH2.