October 01, 2018
My pal adipic acid and I make a lot of nylon.
What molecule am I?
Image of Hexamethylenediamine 3D Image of Hexamethylenediamine

Hexamethylenediamine (formally hexane-1,6-diamine) is a colorless, low-melting solid with an important industrial use. It and adipic acid (Molecule of the Week for February 9, 2015) are the starting materials for manufacturing nylon 6,6, a polyamide used widely in textiles and plastics.

The earliest synthesis of hexamethylenediamine is attributed to Theodor Curtius and Hans Clemm, Heidelberg University (Germany) chemists, who in 1900 made it by hydrogenating adiponitrile. In 1929, biochemists Karl H. Slotta and R. Tschesche at the University of Breslau (Germany) improved this process by generating hydrogen in situ from sodium metal and ethanol.

Nylon 6,6 market value in 2018 is estimated to be more than US$3 billion; this value is expected to double by 2026. For more on the status of the nylon 6,6 industry, see the October 8, 2018, issue of Chemical & Engineering News.

Hexamethylenediamine hazard information

GHS classification*: acute toxicity, oral, category 4
H302—Harmful if swallowedChemical Safety Warning
GHS classification: Acute toxicity, dermal, category 4
H312—Harmful in contact with skinChemical Safety Warning
GHS classification: skin corrosion, category 1B
H314—Causes severe skin burns and eye damageChemical Safety Warning
GHS classification: serious eye damage, category 1
H318—Causes serious eye damageChemical Safety Warning
GHS classification: specific target organ toxicity, single exposure; respiratory tract irritation, category 3
H335—May cause respiratory irritationChemical Safety Warning
GHS classification: hazardous to the aquatic environment, acute hazard, category 3
H402—Harmful to aquatic environment, category 3 

*Globally Harmonized System of Classification and Labeling of Chemicals. Explanation of pictograms.

Hexamethylenediamine fast facts

CAS Reg. No.124-09-4
Empirical formulaC6H16N2
Molar mass116.21 g/mol
AppearanceColorless crystals or clear liquid
Melting point42 ºC
Boiling point205 ºC
Water solubility490 g/L

MOTW update

L-Tartaric acid was the Molecule of the Week for November 10, 2008. It is a wine industry byproduct that is used as a food additive and industrial chemical. Tartaric acid is also important in the history of chemistry because Louis Pasteur, who most people think of mainly as a biologist, used it to demonstrate molecular chirality. Pasteur’s notebooks that described his work, however, turned up missing after his death. For and account of how the “lost” notebooks were found, see this week’s issue of Chemical & Engineering News.

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