heptane brief introduction

N-Heptane is a component of mixed fuel compositions and a solvent in organic chemical reactions.

heptane Basic information

heptane Numbering system

heptane Physical and Chemical Properties

• Appearance and characteristics:

• colorless liquid 

Density:

0.71 g/mL at 20 °C

Boiling point:

98 °C(lit.)

Melting point:

−91 °C(lit.)

Flash point:

30 °F

Refractive index:

n20/D 1.397

Water solubility:

practically insoluble

Stability:

Stable. Incompatible with oxidizing agents, chlorine, phosphorus. Highly flammable. Readily forms explosive mixtures with air.

Storage conditions:

The warehouse is ventilated, low-temperature and dry, and stored separately from oxidants and acids

Steam density:

3.5 (vs air)

Steam pressure:

45.2mmHg at 25°C

security information

• RTECS：

• MI7700000

• Safety instructions:

• S9-S16-S29-S33-S60-S61-S62-S23

• Hazard category code:

• R11; R38; R50/53; R65; R67

• WGK Germany：

• 3

• Dangerous goods transportation code:

• UN 1206 3/PG 2

• Customs code:

• 2901100000

• Hazard category:

• 3

• Packaging grade:

• II

• Dangerous goods signs:

• F

• Signal words:

• Danger

• Hazard prevention instructions:

• P210; P273; P301 + P310; P304 + P340 + P312; P331; P391

• Hazard description:

• H225; H304; H315; H336; H410

• Danger signs:

• GHS02, GHS07, GHS08, GHS09

Production method and purpose

Production method

1. The n-heptane content in the residual oil fraction of platinum reforming (93-102 ℃) is over 57%. The n-alkanes in the 5A molecular sieve gas phase adsorption base are then separated by steam desorption to obtain n-alkanes. Through nickel catalyzed hydrogenation, a small amount of normal alkenes are saturated and converted into normal alkanes, and the iodine value is reduced to below 0.1g/100g iodine to be qualified. Finally, standard n-heptane with a purity of 99.9% was obtained through distillation. Industrial grade n-heptane purification can also be achieved through methods such as concentrated sulfuric acid washing and methanol azeotropic distillation.

2. Carbon and hydrogen fractions of petroleum. May contain n-heptane, dimethylcyclopentane, 3-ethylpentane, methylcyclohexane, and 3-methylcyclohexane.

3. Refining method: In addition to alkanes and cycloalkanes with similar boiling points, heptane also contains unsaturated compounds, water, and benzene. The removal method of benzene is the same as that of hexane. Unsaturated hydrocarbons can be removed by washing with concentrated sulfuric acid, and water can be removed using calcium chloride, phosphorus pentoxide, metallic sodium and potassium, or molecular sieves can be used as solid desiccants. Finally, fractionate and refine.

4. Industrial grade n-heptane can be purified by concentrated sulfuric acid washing, methanol azeotropic distillation, and other methods.

5. Method: In a reaction bottle equipped with a stirrer, reflux condenser, and vent tube (inserted into the bottom of the bottle), add 100g (1.53mol) of zinc mercury amalgam, 250mL of concentrated hydrochloric acid, and 50mL of water. Stir and add 40g (0.35mol) of heptane-4

(2) Slowly introduce hydrogen chloride gas. If the reaction is too intense, pause the supply of hydrogen chloride gas. After 2-3 hours, most of the zinc mercury amalgam reaction is complete. Stop passing hydrogen chloride and let it sit overnight. Remove the mixer and switch to a steam distillation device for steam distillation until the distillate is transparent. Separate the upper oil layer, wash it twice with distilled water, dry it with anhydrous sodium sulfate, and then separate it. Collect the distillate at 97-99 ℃ to obtain heptane ①

(1) 26g with a yield of 74%. Note: ① Most of the products of Clemmensen reduction reactions contain a small amount of unsaturated hydrocarbons. Add about 10% volume of concentrated sulfuric acid and shake thoroughly until the acid layer is colorless or only very light yellow. Separate the acid layer, wash it with 10% saturated sodium carbonate and water in sequence, dry it with anhydrous magnesium sulfate or anhydrous sodium, and then fractional distillation (or vacuum distillation) to obtain high-purity alkanes.

use to

Mainly used as a standard and solvent for octane number determination, as well as for organic synthesis and preparation of experimental reagents.