Heptane is a colorless, flammable liquid commonly used as a solvent. It has a molecular formula of C7H16 and is found in gasoline. Heptane has seven carbon atoms and 16 hydrogen atoms.
| IUPAC Name | Heptane |
| Molecular Formula | C7H16 |
| CAS Number | 142-82-5 |
| Synonyms | n-Heptane, Dipropylmethane, Heptyl hydride, Etc. |
| InChI | InChI=1S/C7H16/c1-3-5-7-6-4-2/h3-7H2,1-2H3 |
Heptane Properties
Heptane Formula
The chemical formula of heptane is C7H16. It consists of seven carbon atoms and 16 hydrogen atoms, arranged in a straight chain. The straight-chain structure of heptane makes it an important member of the alkane family of hydrocarbons.
Heptane Molar Mass
The molar mass of C7H16 is 100.20 g/mol. This value is calculated by adding the atomic masses of all the atoms present in a single molecule of C7H16. The molar mass of C7H16 is an important parameter in many chemical calculations, including stoichiometry, thermodynamics, and kinetics.
Heptane Boiling Point
C7H16 has a boiling point of 98.42°C (209.16°F). This relatively low boiling point makes it a useful solvent for various applications, such as in the laboratory and in the production of gasoline. C7H16’s boiling point is influenced by several factors, including the strength of intermolecular forces and the molecular weight of the compound.
Heptane Melting Point
The melting point of C7H16 is -91°C (-132°F). This low melting point indicates that C7H16 is a liquid at room temperature and is highly volatile. C7H16’s low melting point is due to the weak van der Waals forces between its molecules.
Heptane Density g/mL
The density of C7H16 is 0.684 g/mL at 20°C (68°F). C7H16’s density is a measure of how much mass is present in a given volume. This value is affected by factors such as temperature, pressure, and the purity of the sample.
Heptane Molecular Weight
The molecular weight of C7H16 is 100.20 g/mol. This value is calculated by adding the atomic masses of all the atoms present in a single molecule of C7H16. The molecular weight of C7H16 is a crucial parameter in many chemical reactions, as it helps to determine the amount of reactants and products present in a reaction mixture.
Heptane Structure
C7H16 has a straight-chain structure, with seven carbon atoms and 16 hydrogen atoms arranged in a linear fashion. This structure is a characteristic feature of alkanes, a family of hydrocarbons. C7H16’s structure influences its physical and chemical properties, including its boiling point, melting point, and reactivity.
Heptane Solubility
C7H16 is a nonpolar molecule and is not very soluble in polar solvents such as water. However, C7H16 is highly soluble in nonpolar solvents such as hexane, benzene, and toluene. This solubility behavior is due to the fact that like dissolves like: nonpolar molecules tend to dissolve in nonpolar solvents, while polar molecules tend to dissolve in polar solvents.
| Appearance | Colorless liquid |
| Specific Gravity at 25°C | 0.684 g/mL |
| Color | Colorless |
| Odor | Gasoline-like odor |
| Molar Mass | 100.20 g/mol |
| Density at 25°C | 0.684 g/mL |
| Melting Point | -91°C (-132°F) |
| Boiling Point | 98.42°C (209.16°F) |
| Flash Point | -4°C (25°F) |
| Water Solubility at 25°C | 0.004 g/100 mL |
| Solubility in other solvents | Highly soluble in nonpolar solvents (hexane, toluene, benzene) |
| Vapour Pressure at 20°C | 25.31 mmHg |
| Vapour Density at 20°C | 3.46 (air = 1) |
| pKa | 50 (estimated) |
| pH | Not applicable |
Heptane Safety and Hazards
C7H16 poses several safety hazards, primarily due to its highly flammable nature. It can easily catch fire and release flammable vapors when exposed to heat or flames. The fumes of C7H16 can also irritate the eyes, skin, and respiratory system, causing coughing, wheezing, and shortness of breath. Moreover, C7H16 can be harmful if ingested, causing nausea, vomiting, and abdominal pain. Hence, proper precautions must be taken when handling C7H16, such as using proper protective equipment, ensuring good ventilation in the workspace, and keeping it away from heat sources and open flames. It is also essential to follow proper storage, handling, and disposal protocols for C7H16 to minimize any potential risks.
| Hazard Symbols | F, Xi |
| Safety Description | Highly flammable liquid and vapor. Causes skin irritation. |
| UN IDs | UN 1206 |
| HS Code | 2902.41.000 |
| Hazard Class | 3 (Flammable liquids) |
| Packing Group | II |
| Toxicity | May be harmful if swallowed and can cause skin and eye irritation |
Heptane Synthesis Methods
Various methods exist for synthesizing C7H16, but the primary method involves fractionally distilling petroleum or crude oil. This method separates hydrocarbons based on their boiling points, and distilling the portion of the mixture that boils at a temperature range of 90-100°C yields C7H16.
Another method for C7H16 synthesis is through the catalytic hydrogenation of hexene or other olefins using a palladium catalyst at high temperatures and pressures.
Using the Fischer-Tropsch process, one can synthesize C7H16 by reacting carbon monoxide and hydrogen gas over an iron or cobalt catalyst at high temperatures and pressures. This process produces a mixture of hydrocarbons, including C7H16, which can be separated by fractional distillation.
To synthesize C7H16, one can use a platinum catalyst at high temperatures and pressures to dehydrocyclize methylcyclohexane. Additionally, combining smaller hydrocarbons obtained by cracking naphtha or other petroleum fractions can produce C7H16.
Overall, C7H16 synthesis involves various methods, primarily using petroleum or crude oil as the starting material, and involves various chemical reactions such as distillation, hydrogenation, and dehydrocyclization.
Heptane Uses
C7H16 has several industrial and commercial applications, including:
- Solvent: Commonly used as a solvent in various industries, such as oil and gas, rubber, and adhesive manufacturing. Dissolves a wide range of compounds, including fats, oils, and resins.
- Fuel: Used as a reference fuel for gasoline engines. Commonly used in research laboratories for engine testing and development.
- Extraction: Used as an extraction solvent for natural products, such as vegetable oils, herbal extracts, and essential oils.
- Cleaning: Used as a cleaning agent in the electronics industry. Used to remove contaminants from electronic components.
- Laboratory Reagent: Used as a reagent in various laboratory procedures, including DNA extraction, chromatography, and spectroscopy.
- Paint Thinner: Used as a paint thinner to dilute oil-based paints and to clean painting equipment.
- Adhesive: Used as an adhesive in various applications, such as laminating, bonding, and sealing.
Questions:
Q: What is the value of n in ch3(ch2)nch3 if the name of the hydrocarbon is heptane?
A: The value of n in ch3(ch2)nch3 for heptane is 5.
Q: Is heptane soluble in water?
A: No, C7H16 is not soluble in water as it is a nonpolar hydrocarbon and water is a polar molecule.
Q: Is heptane polar?
A: No, C7H16 is a nonpolar hydrocarbon due to its symmetrical molecular structure and equal sharing of electrons between carbon and hydrogen atoms.
Q: What is heptane?
A: C7H16 is a straight-chain alkane hydrocarbon with the chemical formula C7H16. It is a colorless liquid with a characteristic odor and is commonly used as a reference fuel for gasoline engines.
Q: What is the name of this hydrocarbon? C7H16
A: The name of this hydrocarbon is C7H16.
Q: How many isomers of heptane?
A: C7H16 has nine possible isomers, including straight-chain and branched-chain isomers.
Q: Is heptane volatile?
A: Yes, C7H16 is a volatile liquid with a low boiling point of 98.4 °C and a high vapor pressure.
Q: What is the molecular formula of heptane?
A: The molecular formula of heptane is C7H16.
Q: Which is more polar hexane or heptane?
A: Hexane and C7H16 are both nonpolar hydrocarbons, but C7H16 is slightly more polar than hexane due to its larger molecular size and greater London dispersion forces.
Q: Is heptane covered under PSM?
A: Yes, C7H16 is a covered substance under the Process Safety Management (PSM) regulations, which apply to facilities that handle, use, or store more than a threshold quantity of certain hazardous chemicals.