Amines are organic compounds derived from ammonia (NH3) by replacing one or more hydrogen atoms with a hydrocarbon group. They are classified into three main types depending on the number of hydrocarbon groups bonded to the nitrogen atom:
- Primary amines (1° amines) have one hydrocarbon group bonded to the nitrogen atom.
- Secondary amines (2° amines) have two hydrocarbon groups bonded to the nitrogen atom.
- Tertiary amines (3° amines) have three hydrocarbon groups bonded to the nitrogen atom.
Due to the presence of the amine group (NH2), amines are weakly basic and can form salts with acids. They also have a lone pair of electrons on the nitrogen atom, making them nucleophilic (electron-donating) and able to participate in various chemical reactions.
These properties make many amines reversible acid scavengers capable of capturing CO2 or H2S. A tertiary amine like methyldiethanolamine (MDEA) can be used in CO2 capture operations, while the primary amine monoethanolamine (MEA) finds applications as a H2S scavenger. By changing the pH or adjusting the temperature, the acid can be separated from the amine, enabling a regenerative treatment process.
Here are some of other important uses of primary, secondary, and tertiary amines:
- Pharmaceuticals: Many primary amines are used in the production of pharmaceuticals. Dyes: Some primary amines are used as precursors for the production of dyes.
- Plastics: Certain primary amines are used as curing agents for epoxy resins.
- Corrosion inhibitors: Some secondary amines are used as corrosion inhibitors to protect metals from rust, such as in boiler water systems.
- Rubber chemicals: Certain secondary amines are used as accelerators in the vulcanization of rubber.
- Agrochemicals: Many herbicides and pesticides are tertiary amines.
- Phase-transfer catalysts: Tertiary amines are often used as phase-transfer catalysts to improve the efficiency of chemical reactions between immiscible liquids.
- Fuel additives: Some tertiary amines are used as anti-knock agents in gasoline.
Quantitative Raman Spectroscopy (QRS™) for amine analysis
Quantitative Raman Spectroscopy (QRS™) is ideally suited for rapid,
simple analysis of all amines. Many amines solutions are aqueous — water-based — and Raman spectroscopy is not affected by the water background. Here are a handful of amines with which OndaVia has extensive experience:
- Ethanolamine (CAS: 141-43-5);
- Methylamine (CAS: 74-89-5);
- Morpholine (CAS: 110-91-8);
- Cyclohexylamine (CAS: 108-91-8);
- Methyldiethanolamine (CAS: 105-59-9);
- Dimethylethanolamine (CAS: 108-01-0);
- Diethanolamine (CAS: 111-42-2);
- Piperazine (CAS: 110-85-0);
- Diglycolamine (CAS: 929-06-6);
Have a specific amine analysis need? Contact us to learn more about how QRS can improve your amine processes. Whether as a QA/QC check at manufacturing or at receipt, or as a process monitoring tool, QRS provides the data you need to make the right decision.