3-mercaptopropionic acid
Description
3-Mercaptopropionic acid (CAS 107-96-0), also known as beta-mercaptopropionic acid and abbreviated as 3-MPA, is a bifunctional thiol acid used across polymer chemistry and pharmaceutical synthesis.
Its dual reactive sites, a thiol group and a carboxylic acid, make it a practical building block and chain transfer agent in industrial processes and food flavoring applications.
In polymer manufacturing, 3-MPA acts as a chain transfer agent during free-radical polymerization, allowing formulators to control molecular weight in acrylic and vinyl-based resins.
The pharmaceutical and biotech sectors use it as a linker or intermediate in peptide conjugation and nanoparticle surface functionalization, particularly in gold nanoparticle synthesis.
Assigned FEMA 4587, it is approved as a flavoring agent in food applications where sulfur-containing compounds contribute to meat, savory, and roasted flavor profiles.
It also functions as a catalyst precursor and stabilizer in PVC processing, where it supports organotin-based heat stabilizer formulations for industrial manufacturing.
3-Mercaptopropionic acid is supplied as a clear to pale yellow liquid. Standard commercial grades include technical and high-purity variants to meet specific synthesis requirements.
Pharmaceutical-grade material is available for bioconjugation needs. Packaging typically ranges from small laboratory quantities up to bulk drum supply for large-scale operations.
Physical Properties
| Melting Point | 16.8 °C |
| Boiling Point | 111 °C @ Press: 15 Torr |
| Density | 1.218 g/cm³ @ Temp: 21 °C |
| Flash Point | 201 °F |
| Appearance | clear colourless to yellowish liquid after melting |
| Color | White |
| Odor | sulfurous roasted |
| Form | Crystalline Powder, Crystals, and/or Chunks |
| Water Solubility | soluble |
| Vapor Pressure | 0.04 mm Hg ( 20 °C) |
| Refractive Index | n 20/D 1.492(lit.) |
| pH | 2 (120g/l, H2O, 20℃) |
| Log P | -2.3 at 22℃ |
Safety & Handling (Learn More)
Trade & Regulatory
| HS Code | 29309070 |
| UN Number | 2922 |
| ADR Class | 8 |
| Packing Group | II |
| WGK (Germany) | 1 |
Documentation
Other Names
beta-thiopropionic acid|beta-mercaptopropionic acid|3-thiopropionic acid|3-thiopropanoic acid|3-thiolpropanoic acid|3-thiohydracrylic acid|2-mercaptoethanecarboxylic acid|3MPA|3-MPA
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