Amine value

In organic chemistry, amine value is a measure of the nitrogen content of an organic molecule.^[1] Specifically, it is usually used to measure the amine content of amine functional compounds.^[2] It may be defined as the number of milligrams of potassium hydroxide (KOH) equivalent to one gram of epoxy hardener resin. The units are thus mg KOH/g.

List of ASTM methods

There are a number of ASTM analytical test methods to determine amine value. A number of states in the United States have adopted their own test methods but they are based on ASTM methods.^[3] Although there are similarities with the method it is not the same as an acid value.

• ASTM D2073 - This is a potentiometric method.^[4]
• ASTM D2074-07
• ASTM D2896 - potentiometric method with perchloric acid.^[5]
• ASTM D6979-03

First principles

The amine value is useful in helping determine the correct stoichiometry of a two component amine cure epoxy resin system.^[6][7][8]

It is the number of Nitrogens x 56.1 (Mwt of KOH) x 1000 (convert to milligrams) divided by molecular mass of the amine functional compound. So using Tetraethylenepentamine (TEPA) as an example: Mwt = 189, number of nitrogen atoms = 5

So 5 x 1000 x 56.1/189 = 1484. So the Amine Value of TEPA = 1484

Other amines

All numbers are in units of mg KOH/g.

• Ethylenediamine. Amine value = 1870
• Diethylenetriamine. Amine value = 1634
• Triethylenetetramine. Amine value = 1537
• Aminoethylpiperazine. Amine value = 1305
• Isophorone diamine. Amine value = 660
• Hexamethylenediamine. Amine value = 967
• 1,2-Diaminocyclohexane. Amine value = 984
• 1,3-BAC. Amine value = 790
• 2-Methylpentamethylenediamine -Dytek A. Amine value = 967
• m-Xylylenediamine -MXDA. Amine value = 825

See also-related test methods

• Acid value
• Bromine number
• Epoxy value
• Hydroxyl value
• Iodine value
• Peroxide value
• Saponification value