Diazolidinylurea (78491-02-8) Physical and Chemical Properties
Diazolidinylurea
Diazolidinylurea is an imidazolidinone-class antimicrobial preservative and formaldehyde-releasing agent used by formulators to control microbial growth in personal care and household products.
| CAS Number | 78491-02-8 |
| Family | Imidazolidinones (formaldehyde-releasers) |
| Typical Form | Powder or viscous liquid |
| Common Grades | EP, Technical Grade |
Diazolidinylurea is a hydroxymethylated imidazolidinone derivative belonging to the class of hydantoin/urea hybrid compounds. Structurally it combines an imidazolidine-2,4-dione (hydantoin) core that is N-substituted by a urea moiety; both heterocyclic nitrogen centers and the urea carbonyls are decorated with multiple hydroxymethyl groups. The molecule contains numerous hydrogen-bond donors and acceptors and a formal neutral net charge, producing a compact, highly polar polyol-like architecture with limited intrinsic lipophilicity.
Electronic and intermolecular features are dominated by the carbonyl-rich heterocycle and urea functionalities plus five hydroxyl moieties (hydroxymethyl groups). These groups yield extensive intra- and intermolecular hydrogen bonding, a large polar surface area, and high aqueous affinity; they also provide sites for reversible formaldehyde release via decomposition of hydroxymethyl substituents under certain conditions. Acid–base properties are essentially non-ionizable under normal pH ranges (no strongly acidic or basic functional groups), so partitioning behavior is governed mainly by polarity and hydrogen-bonding rather than ionization. The compound is therefore strongly hydrophilic (low partition coefficient) and thermally/chemically less volatile than small organic solvents, but it can slowly hydrolyze or decompose to release formaldehyde under conditions that cleave hydroxymethyl groups (acidic or heated aqueous environments).
Functionally, diazolidinylurea is used industrially as an antimicrobial preservative and a formaldehyde-releasing agent in aqueous consumer and cosmetic formulations, where its solubility and preservative activity are advantageous. Its use is balanced against sensitization potential in topical applications and the known hazards associated with formaldehyde release.
Common commercial grades reported for this substance include: EP, Technical Grade.
Basic Physical Properties
Density
No experimentally established value for this property is available in the current data context.
Melting Point
No experimentally established value for this property is available in the current data context.
Boiling Point
No experimentally established value for this property is available in the current data context.
Vapor Pressure
No experimentally established value for this property is available in the current data context.
Flash Point
No experimentally established value for this property is available in the current data context.
Chemical Properties
Solubility and Phase Behavior
Experimentally described physical form: Liquid. The molecule's combination of multiple hydroxymethyl groups, urea and hydantoin carbonyls produces a high density of hydrogen-bond donors and acceptors (Hydrogen bond donors: 5; Hydrogen bond acceptors: 7) and a large topological polar surface area (TPSA: 154). These descriptors are consistent with high miscibility or solubility in water and other polar protic solvents and with negligible solubility in nonpolar organic solvents. In formulated systems the compound is compatible with aqueous matrices but may partition minimally into oil phases; solubilization aids (co-solvents or emulsifiers) are typically required to incorporate significant amounts into nonaqueous phases.
Reactivity and Stability
Diazolidinylurea contains hydroxymethyl substituents that can undergo reversible decomposition to release formaldehyde; this formaldehyde-releasing chemistry is the primary antimicrobial mechanism in many formulations. Stability is generally acceptable in neutral, cool aqueous systems but decreases with increasing temperature and under acidic conditions that favor cleavage of hydroxymethyl groups. The presence of nucleophiles, strong acids, or oxidizing agents can accelerate decomposition. Given the propensity to release formaldehyde, decomposition products should be considered when assessing compatibility and long-term stability of finished products.
Thermodynamic Data
Standard Enthalpies and Heat Capacity
No experimentally established value for this property is available in the current data context.
Molecular Parameters
Molecular Weight and Formula
- Molecular formula: C8H14N4O7
- Molecular weight: 278.22
Additional computed masses: ExactMass / MonoisotopicMass: 278.08624880.
Other computed molecular descriptors: Heavy Atom Count: 19; Complexity: 376; Rotatable Bond Count: 5.
LogP and Polarity
- XLogP (computed): -2.5
- Topological Polar Surface Area (TPSA): 154
These descriptors quantify strong hydrophilicity and low lipophilicity; the negative XLogP value and large TPSA are consistent with aqueous solubility and limited membrane partitioning.
Structural Features
Diazolidinylurea is formally described as 1-[1,3-bis(hydroxymethyl)-2,5-dioxoimidazolidin-4-yl]-1,3-bis(hydroxymethyl)urea (IUPAC). Key structural motifs: - Imidazolidine-2,4-dione (hydantoin) core providing two carbonyl acceptors and two ring nitrogens. - N-linked urea functionality substituting the hydantoin ring, itself carrying two hydroxymethyl substituents. - A total of five hydroxymethyl groups capable of hydrogen bonding and formaldehyde release. These motifs produce extensive intramolecular hydrogen bonding networks, high polarity, and several rotatable linkages leading to conformational flexibility in solution.
Identifiers and Synonyms
Registry Numbers and Codes
- CAS Number: 78491-02-8
- European Community (EC) Number: 278-928-2
- UNII: N9VX1IBW6K (alternate UNII reported: H5RIZ3MPW4)
- ChEBI: CHEBI:136014
- ChEMBL: CHEMBL3187032
- DrugBank: DB14173
- DSSTox Substance ID: DTXSID0029559
Also available: InChI, InChIKey and SMILES (see next subsection).
Synonyms and Structural Names
Representative synonyms reported for this substance include:
- diazolidinylurea
- diazolidinyl urea
- 5-(1,3-bis(hydroxymethyl)ureido)-1,3-bis(hydroxymethyl)imidazol-2,5(3H,5H)dione
- 1-[1,3-bis(hydroxymethyl)-2,5-dioxoimidazolidin-4-yl]-1,3-bis(hydroxymethyl)urea
- Germall II
- Germaben II-E
- N,N'-Bis(hydroxymethyl) urea
Structural identifiers (canonical strings):
- SMILES: C(NC(=O)N(CO)C1C(=O)N(C(=O)N1CO)CO)O
- InChI: InChI=1S/C8H14N4O7/c13-1-9-7(18)10(2-14)5-6(17)12(4-16)8(19)11(5)3-15/h5,13-16H,1-4H2,(H,9,18)
- InChIKey: SOROIESOUPGGFO-UHFFFAOYSA-N
Industrial and Commercial Applications
Representative Uses and Industry Sectors
Diazolidinylurea is used primarily as an antimicrobial preservative in aqueous personal-care and household products. Representative applications include cosmetics, skin care products, shampoos and conditioners, bubble baths, baby wipes, and household detergents. Its preservative action derives from slow formaldehyde release under formulation-appropriate conditions, providing broad-spectrum antimicrobial efficacy in many rinse-off and some leave-on systems. Large-scale use in formulated products corresponds to multi-ton annual production volumes in industrial reporting.
Commercial grades reported for this substance: EP, Technical Grade.
Role in Synthesis or Formulations
Functionally the compound is added to aqueous formulations to inhibit microbial growth; it is selected for solubility in water-based systems, low volatility, and ease of incorporation. Formulators balance preservative concentration and product pH/temperature to manage formaldehyde release rates and minimize sensitization risk. Compatibility with reducing agents, reactive aldehydes, or amine-rich components should be evaluated because interactions can affect preservative efficacy and decomposition pathways.
Safety and Handling Overview
Acute and Occupational Toxicity
Diazolidinylurea is classified in multiple notifications as a skin sensitizer and eye irritant. Reported hazard statements include H317: May cause an allergic skin reaction, H319: Causes serious eye irritation, and H315: Causes skin irritation in some notifications. The compound is a formaldehyde releaser; formaldehyde itself is a recognized human carcinogen and can contribute to systemic and local toxicity when released in sufficient quantities. Routes of potential occupational exposure include dermal contact, inhalation and, less commonly, ingestion. Clinical and animal data indicate that sensitization and contact dermatitis are the primary adverse human effects associated with topical exposure.
Storage and Handling Considerations
Store in a cool, well-ventilated area in tightly closed containers to minimize degradation and unintended formaldehyde formation. Avoid exposure to elevated temperatures and strong acids or oxidizers which can accelerate decomposition. Use standard industrial hygiene practices: chemical-resistant gloves, eye protection, and protective clothing for handling concentrates; local exhaust ventilation where aerosols or mists may be generated. Spill control should prioritize containment and removal into appropriate waste streams; avoid release to aquatic environments. For detailed hazard, transport and regulatory information, users should refer to the product-specific Safety Data Sheet (SDS) and local legislation.
