Triethanolamine lactate (20475-12-1) Physical and Chemical Properties
Triethanolamine lactate
An organic triethanolammonium lactate salt commonly used in formulations as a humectant and pH-modifying component for cosmetic and personal‑care applications.
| CAS Number | 20475-12-1 |
| Family | Organic amine salt (lactate) |
| Typical Form | Viscous liquid / aqueous solution |
| Common Grades | EP |
Triethanolamine lactate is an organic salt formed by proton transfer between triethanolamine (a tertiary amine bearing three 2-hydroxyethyl substituents) and lactic acid (2-hydroxypropionic acid). Structurally it is best described as a 1:1 protonated triethanolamine cation paired with a lactate anion; alternate stoichiometric representations in the compositional data include the component pair \(\ce{C6H15NO3.C3H6O3}\) and the consolidated molecular formula \(\ce{C9H21NO6}\). The salt is highly polar and rich in hydrogen-bond donors and acceptors; the neutral formal charge on the covalently-bonded unit count conceals the ionic nature of the proton-transfer complex (triethanolammonium / lactate).
Electronically, the material combines a basic tertiary amine core (readily protonated to the triethanolammonium cation under acidic conditions) with an alpha-hydroxy carboxylate anion. The presence of multiple hydroxyl groups and the carboxylate give high hydrophilicity, extensive intermolecular hydrogen bonding, and a proclivity for strong solvation in polar protic solvents. Acid–base behavior is dominated by the conjugate acid–base pair: the tertiary amine is weakly basic in its free form and exists as the ammonium cation in the salt; the lactic acid component is present as the lactate anion. These features produce low intrinsic volatility, low lipophilicity, and a tendency to act as a humectant and solubilizer in aqueous formulations.
Functionally, triethanolamine lactate is used to deliver the combined attributes of buffering (mildly basic conjugate), moisture retention, and surface-activity modulation in personal-care and similar consumer formulations. The ingredient is widely applied where skin conditioning and humectancy are required with nonvolatile, water-compatible performance. Common commercial grades reported for this substance include: EP.
Basic Physical Properties
Solubility and Hydration
No experimentally established value for this property is available in the current data context.
Thermal Stability and Decomposition
No experimentally established value for this property is available in the current data context.
Chemical Properties
Complex Formation and Coordination
Triethanolamine (when unprotonated) is a polyvalent ligand capable of functioning as a tridentate donor through its tertiary nitrogen and two or three hydroxyl-containing arms; however, in the protonated triethanolammonium form present in the salt the lone pair on nitrogen is occupied and metal-coordination via nitrogen is suppressed. Complexation behavior in formulations therefore depends on the fraction of free (unprotonated) triethanolamine: at higher pH, deprotonated amine character increases and chelation tendencies rise. The lactate anion (\(\ce{CH3CH(OH)COO^-}\)) can act as a monodentate or bridging ligand in metal complexes but is primarily a solvated counter-ion in typical aqueous consumer formulations. Overall, the salt pair can influence metal ion solubility and stability in formulations through a combination of weak coordination (from lactate) and ligand exchange dynamics if unprotonated amine is present.
Reactivity and Stability
As an organic ammonium carboxylate salt with multiple hydroxyl groups, triethanolamine lactate is chemically stable under ambient, neutral-to-mildly basic aqueous conditions but may release free triethanolamine (base) or lactic acid under strongly acidic or basic extremes. The high density of hydroxyl functionality increases susceptibility to oxidative degradation under harsh oxidative conditions and can promote microbial growth in aqueous systems without appropriate preservation. Hydrolytic cleavage of the salt as a discrete process is not expected; rather, acid–base equilibration controls the partitioning between protonated and free species. No specific decomposition temperatures or kinetic stability constants are provided in the current data context.
Molecular Parameters
Molecular Weight and Composition
Molecular weight: 239.27 (reported value). When expressed as constituent components the compound is a 1:1 association of triethanolamine and lactic acid with component formula \(\ce{C6H15NO3.C3H6O3}\); the consolidated molecular formula is \(\ce{C9H21NO6}\). Exact mass / monoisotopic mass: 239.13688739 (reported value). Topological polar surface area (TPSA): 121 (reported value). Heavy atom count: 16 (reported value).
Additional computed descriptors (reported): hydrogen-bond donor count 5; hydrogen-bond acceptor count 7; rotatable bond count 7; formal charge 0; complexity 115; undefined atom stereocenter count 1.
LogP and Ionization State
No experimentally established value for this property is available in the current data context.
Ionization and ionic form: the material exists as a proton-transfer salt comprising a triethanolammonium cation and a lactate anion. The lactate anion can be represented as \(\ce{CH3CH(OH)COO^-}\) and the protonated amine as \(\ce{(HOCH2CH2)3NH+}\); in bulk composition the covalently-connected stoichiometry is neutral overall (formal charge 0 reported) but the local ionic pairing governs solvation, conductivity in solution, and pH behavior.
Identifiers and Synonyms
Registry Numbers and Codes
- CAS RN: 20475-12-1
- Deprecated CAS: 76788-91-5
- EC number: 243-846-8
- UNII: 064C51N81O
- DSSTox Substance ID: DTXSID60885138
- RXCUI: 1312086
- Wikidata: Q27236172
- InChIKey:
RJQQOKKINHMXIM-UHFFFAOYSA-N - InChI:
InChI=1S/C6H15NO3.C3H6O3/c8-4-1-7(2-5-9)3-6-10;1-2(4)3(5)6/h8-10H,1-6H2;2,4H,1H3,(H,5,6) - SMILES:
CC(C(=O)O)O.C(CO)N(CCO)CCO
(Per identifier conventions, SMILES, InChI and InChIKey are presented as inline strings.)
Synonyms and Structural Names
Reported synonyms and structural names include: Triethanolamine lactate; TEA-Lactate; Tris(2-hydroxyethyl)ammonium lactate; TRIETHANOLAMMONIUM LACTATE; LACTIC ACID TRIETHANOLAMINE SALT; 2-[bis(2-hydroxyethyl)amino]ethanol;2-hydroxypropanoic acid; and related depositor-supplied names and legacy identifiers.
Industrial and Commercial Applications
Use as Salt Form or Excipient
Triethanolamine lactate is used primarily as a humectant and skin-conditioning agent in personal-care formulations. The salt form combines buffering capacity, moisture-retention, and solvent-compatible properties that are advantageous in aqueous cosmetic systems. As an ammonium carboxylate it provides ionic strength modulation without introducing volatile basic amines or free organic acids at formulation pH where the salt is stable.
Representative Use Cases
Representative practical uses are as a moisturizing agent and pH-modifier in topical formulations where nonvolatile, water-compatible humectants are required. Its multifunctional hydroxyl-rich structure makes it useful in emulsions, lotions, and certain rinse-off and leave-on products to improve tactile properties and water-binding capacity. No concise application summary beyond these class-level functions is available in the current data context; in practice this substance is selected based on its general properties described above.
Safety and Handling Overview
Toxicological Considerations
Safety evaluations reported for triethanolamine-containing ingredients indicate that formulations containing triethanolamine and related salts can be safe for intended cosmetic use when formulated to be nonirritating and when levels of free secondary amines (e.g., diethanolamine) are controlled. Reported hazard classifications in various notifications include skin and eye irritation/damage hazard statements (H315: causes skin irritation; H318: causes serious eye damage) for some formulations or submissions. Classification and hazard communication have varied among submitters, reflecting differences in impurities, concentration, and formulation context. Users must consider potential irritation, particularly to eyes and damaged skin, and assess the presence of secondary amines or nitrosatable precursors when designing formulations.
For detailed hazard, transport and regulatory information, users should refer to the product-specific Safety Data Sheet (SDS) and local legislation.
Storage and Handling Guidelines
Handle in well-ventilated areas with appropriate personal protective equipment to prevent skin and eye contact. Because the material is highly hydrophilic and may be hygroscopic in concentrated form, containers should be kept tightly closed and stored under conditions that prevent contamination and microbial growth; use of preservatives in aqueous formulations may be required. Avoid generation of aerosols and prolonged exposure of skin; for spills, contain and absorb with suitable inert material and transfer to appropriate containers for disposal. For detailed hazard, transport and regulatory information, users should refer to the product-specific Safety Data Sheet (SDS) and local legislation.
