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Imidazolidin-2-one, better known in industry as ethyleneurea or 2-imidazolidinone, is a five-membered cyclic urea with CAS No 120-93-4 and the formula C3H6N2O, supplied as a white crystalline solid, as a hemihydrate or as an aqueous solution, and used mainly as a formaldehyde scavenger in textile finishing, wood-based panels and amino resins, and as an intermediate for textile resins, solvents, pharmaceuticals and specialty chemicals.
Ethyleneurea is valued because its two N–H groups react readily with formaldehyde and with N-methylol groups, so it can capture free formaldehyde in resins, finishing baths and finished goods while remaining a stable, highly water-soluble and easy-to-dose solid.
The cyclic urea works by forming stable hydroxymethyl and methylene-bridged adducts with formaldehyde, which lowers free formaldehyde content and formaldehyde emissions, and the same reactivity makes it a building block for N-methylol resins and substituted imidazolidinones.
CAS No: 120-93-4
EC No: 204-436-4
Molecular formula: C3H6N2O
Molecular weight: 86.09 g/mol
Appearance: White to off-white crystalline powder
Melting point: approx. 129–132 °C (anhydrous)
Boiling point: approx. 335 °C (1013 hPa)
Water solubility: approx. 950 g/L (20 °C)
Other forms: Hemihydrate (CAS 121325-67-5), aqueous solutions
COMMON PRODUCT & CHEMICAL NAMES OF IMIDAZOLIDIN-2-ONE:
Imidazolidin-2-one, 2-Imidazolidinone, 2-Imidazolidone, Imidazolidinone, Ethyleneurea, Ethylene Urea, N,N'-Ethyleneurea, 1,3-Ethyleneurea, Monoethyleneurea, 2-Oxoimidazolidine, Imidazolid-2-one, Urea, N,N'-(1,2-ethanediyl)-, Urea, 1,3-ethylene-, EU, 2-Imidazolidinone Hemihydrate, Ethyleneurea Hemihydrate, Ethylene Urea 87 %, Ethylene Urea Solution
Imidazolidin-2-one is the preferred IUPAC name, while 2-imidazolidinone and 2-imidazolidone are common chemical names. Ethyleneurea (or ethylene urea) is the name most often used in the textile, wood and resin industries, and "Urea, N,N'-(1,2-ethanediyl)-" is the CAS index name. The abbreviation EU is used in the textile and resin literature, mainly in names of derived resins such as DMEU.
The formaldehyde scavenger should not be confused with several closely related products. 2-Imidazolidinone hemihydrate (CAS 121325-67-5) is the same molecule with half a mole of crystal water and a much lower melting point. 1-(2-Aminoethyl)imidazolidin-2-one (CAS 6281-42-1), ethylenethiourea (ETU, CAS 96-45-7), 1,3-dimethyl-2-imidazolidinone (DMI, CAS 80-73-9), dimethylol ethyleneurea (DMEU) and dimethylol dihydroxyethyleneurea (DMDHEU) are different substances with their own CAS numbers, properties and hazards.
WHAT IS IMIDAZOLIDIN-2-ONE?
Ethyleneurea is the simplest cyclic urea built on an ethylene bridge. Its ring contains three carbon atoms and two nitrogen atoms, with a carbonyl group (C=O) between the two nitrogens. It can be regarded as urea in which the two nitrogen atoms are joined by a –CH2–CH2– group, which is why it is called ethyleneurea.
Industrially, Imidazolidin-2-one is produced mainly by condensation of ethylenediamine with urea, releasing ammonia. Other known routes use ethylenediamine with dimethyl carbonate (releasing methanol) or ethylene glycol with urea (releasing water). The crude product is purified by distillation and/or crystallization.
In commerce, Imidazolidin-2-one is offered in different forms. High-purity anhydrous material is used mainly in laboratories and in pharmaceutical and fine chemical synthesis. The hemihydrate, sometimes sold as "ethylene urea 87 %", and aqueous solutions (for example around 30 %) are common in textile and wood applications because they are easier to dissolve and dose.
The cyclic urea forms colorless to white crystals that are very soluble in water and soluble in methanol, but only slightly soluble in less polar solvents such as ether or chloroform. The anhydrous compound melts at about 129–132 °C, while the hemihydrate melts at a much lower temperature, around 58 °C.
The formaldehyde scavenger is also formed in the environment and in organisms as a degradation and metabolic product of ethylenethiourea (ETU), which itself comes from ethylenebis(dithiocarbamate) fungicides such as mancozeb. For this reason it appears in pesticide residue studies, but it is not used as a pesticide itself.
The main commercial value of Imidazolidin-2-one lies in its reaction with formaldehyde. Formaldehyde-based resins are still widely used in wrinkle-resistant textile finishes, particleboard and MDF adhesives, and many coatings and auxiliaries. These resins can release free formaldehyde during production and use. Ethyleneurea is added to the resin, to the finishing bath or to the finished surface to bind this free formaldehyde and reduce emissions.
The cyclic urea is also an important intermediate. With formaldehyde it gives dimethylol ethyleneurea (DMEU), one of the classic crosslinking agents for easy-care cotton finishing. It is used as a starting material for 1,3-dimethyl-2-imidazolidinone (DMI), a high-boiling polar aprotic solvent, and as a building block for active pharmaceutical ingredients such as the side chains of the antibiotics azlocillin and mezlocillin.
For manufacturers, Imidazolidin-2-one offers a practical way to meet formaldehyde limits for textiles and wood-based panels without completely changing the resin system. Because it is highly water-soluble, it can be dosed directly into aqueous resins and finishing baths.
For the end user, the use of Imidazolidin-2-one in suitable systems helps provide easy-care textiles and furniture panels with lower formaldehyde release, supporting compliance with emission standards and product labels.
The formaldehyde scavenger can be evaluated in textile finishing, urea-formaldehyde and melamine-urea-formaldehyde resins, wood panel post-treatment, leather and rubber auxiliaries, coatings, fragrance applications and organic synthesis.
CAS NO, EC / EINECS NO AND CHEMICAL IDENTIFICATION OF IMIDAZOLIDIN-2-ONE
Product name: Imidazolidin-2-one / Ethyleneurea
Common abbreviation: EU
Chemical name: Imidazolidin-2-one (2-imidazolidinone)
CAS No: 120-93-4 (anhydrous), 121325-67-5 (hemihydrate)
EC / EINECS No: 204-436-4
Molecular formula: C3H6N2O (anhydrous), C3H6N2O · 0.5 H2O (hemihydrate)
Molecular weight: 86.09 g/mol (anhydrous), 95.10 g/mol (hemihydrate)
SMILES: O=C1NCCN1
InChIKey: YAMHXTCMCPHKLN-UHFFFAOYSA-N
Chemical class: Cyclic urea, saturated heterocyclic compound (imidazolidinone)
Main functions: Formaldehyde scavenger, intermediate for N-methylol textile resins (DMEU), intermediate for DMI and pharmaceutical building blocks, modifier in amino resins, polar organic intermediate
The correct EC number of Imidazolidin-2-one is 204-436-4. The number 204-438-6, which sometimes appears in product listings, does not belong to this substance and should not be used.
Because Imidazolidin-2-one is sold both as an anhydrous solid and as a hemihydrate or solution, the CAS number on the documents should match the product actually delivered. The active content (calculated as anhydrous ethyleneurea) is the key value when dosing.
CHEMICAL STRUCTURE AND MOLECULAR PROPERTIES OF IMIDAZOLIDIN-2-ONE
The Imidazolidin-2-one ring is a saturated five-membered ring. The carbonyl group is flanked by two N–H groups, and the two remaining ring carbons are CH2 groups. This urea-type arrangement makes the molecule small, compact and very polar.
Ethyleneurea has two hydrogen bond donors (the N–H groups) and one strong hydrogen bond acceptor (the carbonyl oxygen). Its calculated log P is around –1.3, which explains its very high water solubility and low solubility in non-polar solvents. In the solid state, strong hydrogen bonding between molecules gives a relatively high melting point for such a small molecule.
The N–H groups are the reactive sites. Like other ureas, Imidazolidin-2-one reacts with formaldehyde to form N-hydroxymethyl (N-methylol) derivatives. Monomethylol and dimethylol ethyleneurea are formed depending on the ratio of formaldehyde to Imidazolidin-2-one and on the pH. Under acidic conditions, these methylol groups can further condense to methylene bridges.
This reactivity works in two directions. When Imidazolidin-2-one is the main component and formaldehyde is added deliberately, it produces crosslinking resins such as DMEU. When Imidazolidin-2-one is added in excess to a system that contains free formaldehyde, it acts as a scavenger and ties up the formaldehyde in stable adducts.
The N–H groups can also be alkylated or acylated. Methylation gives 1,3-dimethyl-2-imidazolidinone (DMI), and acylation with phosgene derivatives gives reactive intermediates such as 2-oxoimidazolidine-1-carbonyl chloride, used in pharmaceutical synthesis.
HOW DOES IMIDAZOLIDIN-2-ONE WORK AT THE MOLECULAR LEVEL?
Imidazolidin-2-one, also known as ethyleneurea or 2-imidazolidinone, is a cyclic urea. Its five-membered ring contains a carbonyl group flanked by two nitrogen atoms, each carrying a hydrogen, and an ethylene bridge closing the ring. This compact structure combines two strong hydrogen-bond donors, the N–H groups, with one strong acceptor, the carbonyl oxygen, and two reactive nitrogen sites. Its uses as a formaldehyde scavenger, a building block for crosslinkers and adhesion monomers, and a chemical intermediate all follow from these features.
Polarity and hydrogen bonding: The urea unit is strongly polar because electron density is shared between the nitrogen atoms and the carbonyl oxygen. In the solid state, the N–H groups of one molecule bond to the carbonyl oxygens of neighbours, giving a hydrogen-bonded crystal with a relatively high melting point. In water, the same groups interact with water molecules, so ethyleneurea dissolves readily. These interactions also allow it to bind to polar surfaces such as cellulose, wood, metal oxides and mineral substrates.
Reaction with formaldehyde: The N–H hydrogens of the cyclic urea are reactive toward formaldehyde. Each nitrogen can add one formaldehyde molecule to form an N-hydroxymethyl, or methylol, group. This reaction consumes free formaldehyde and converts it into bound forms that are far less volatile. Imidazolidin-2-one is therefore added to textile finishes, wood and paper resins and some coatings as a formaldehyde scavenger, lowering the level of free formaldehyde released from the finished product.
Precursor to cellulose crosslinkers: When both nitrogen atoms carry methylol groups, the resulting dimethylol ethyleneurea becomes a bifunctional crosslinker. Under acidic catalysis and heat, the methylol groups react with hydroxyl groups of cellulose, forming ether bridges between neighbouring cellulose chains. These bridges limit chain movement when the fibre is wet or creased, giving durable-press and crease-resistant properties to cotton fabrics. Ring-substituted versions, such as dimethylol dihydroxyethyleneurea, use the same chemistry with improved stability and lower formaldehyde release.
Wet adhesion in coatings: Ethyleneurea rings can be attached to polymerisable groups, for example in ureido-functional methacrylate monomers. When small amounts of these monomers are copolymerised into acrylic latex binders, the cyclic urea groups remain on the polymer chain. In the dried paint, they form strong, multiple hydrogen bonds with polar sites on old paint, wood, metal or mineral surfaces. Because these interactions persist when water is present, the coating keeps its adhesion under wet or humid conditions. This mechanism is known as wet adhesion promotion.
Reactivity of the nitrogen atoms: Beyond formaldehyde, the ring nitrogens can be alkylated, acylated or attached to other functional groups. Methylation of both nitrogens gives 1,3-dimethyl-2-imidazolidinone, a polar aprotic solvent used in demanding organic reactions and polymer processing. Other substitutions produce imidazolidinone-based intermediates for pharmaceuticals, agrochemicals and specialty polymers. In each case, the stable five-membered ring provides a rigid, polar core around which the rest of the molecule is built.
Stability of the ring: The cyclic urea is relatively resistant to hydrolysis under neutral and mildly acidic or alkaline conditions, because the delocalised N–C=O system stabilises the ring. Strong acids or bases at high temperature can eventually open it, releasing ethylenediamine and carbon dioxide-derived products. This stability allows ethyleneurea-based finishes and monomers to survive processing and use.
Behaviour in products: In finished goods, bound ethyleneurea units contribute mainly through hydrogen bonding and crosslinking rather than through free reactive groups. Residual free imidazolidin-2-one remains water-soluble and can act as an additional scavenger for formaldehyde released over time.
Performance depends on concentration, pH, temperature, catalyst type, curing conditions and the amount of formaldehyde or reactive hydroxyl groups present. Imidazolidin-2-one dosage and process conditions should therefore be confirmed through laboratory trials.
PHYSICAL AND CHEMICAL PROPERTIES OF IMIDAZOLIDIN-2-ONE
GENERAL TECHNICAL SPECIFICATIONS:
PHYSICAL APPEARANCE: WHITE TO OFF-WHITE CRYSTALLINE POWDER OR CRYSTALS (ANHYDROUS), WHITE CRYSTALS (HEMIHYDRATE), CLEAR AQUEOUS SOLUTION (SOLUTION GRADES)
Odor: Odorless or nearly odorless
Chemical character: Cyclic urea, polar, weakly basic, non-ionic
Molecular formula: C3H6N2O
Molecular weight: 86.09 g/mol
CAS No: 120-93-4
EC / EINECS No: 204-436-4
Purity (assay): Laboratory grades typically min. 96–97 %, technical grades are offered as hemihydrate or solutions with stated active content
Melting point: Approx. 129–132 °C (anhydrous), approx. 58 °C (hemihydrate)
Boiling point: Approx. 335 °C at 1013 hPa
Density: Approx. 1.15 g/cm³
Flash point: Approx. 265 °C
Ignition temperature: Approx. 420 °C
Water solubility: Very high, approx. 950 g/L at 20 °C
Solubility in other solvents: Soluble in methanol, slightly soluble in ether and chloroform
pH: Approx. 9–11 (100 g/L, hemihydrate, 20 °C)
Log P: Approx. –1.3 (calculated)
Reactivity: Reacts with formaldehyde and other aldehydes, stable under normal storage, avoid strong oxidizing agents and strong acids
The difference between the anhydrous material and the hemihydrate is important in practice. The hemihydrate contains roughly 90 % anhydrous Imidazolidin-2-one, melts at a much lower temperature and dissolves easily. When an anhydrous specification is replaced by a hemihydrate, the dose should be recalculated on an active basis.
The cyclic urea is hygroscopic to some extent and should be kept dry. Aqueous solutions are alkaline and are generally stable at room temperature, but their shelf life is usually shorter than that of the solid.
These values are typical data from supplier documentation and reference sources and are not a binding specification for a specific delivery. For the current specification of the supplied Imidazolidin-2-one grade, please contact Ataman Kimya.
HOW DOES IMIDAZOLIDIN-2-ONE CAPTURE FORMALDEHYDE?
The scavenging effect of Imidazolidin-2-one is a chemical reaction, not a physical adsorption.
REACTION WITH FREE FORMALDEHYDE
Free formaldehyde in water exists mainly as methylene glycol. The N–H groups of Imidazolidin-2-one add to formaldehyde to form N-hydroxymethyl groups. One molecule of Imidazolidin-2-one can bind up to two molecules of formaldehyde, one on each nitrogen. These adducts are much less volatile than formaldehyde itself.
REACTION WITH N-METHYLOL GROUPS
In textile and amino resins, part of the formaldehyde is bound as N-methylol groups that can release formaldehyde again during curing, storage or washing. The formaldehyde scavenger can react with these groups, transferring or bridging them into more stable structures and lowering the formaldehyde that can later be released.
CONDENSATION DURING CURING
During heat curing under acidic catalysis, the methylol adducts of Imidazolidin-2-one can condense further, forming methylene bridges and becoming part of the resin network. This helps keep the scavenger in the material rather than leaving it as a free additive.
THE FUNCTIONS OF IMIDAZOLIDIN-2-ONE CAN BE SUMMARIZED AS:
REDUCING FREE FORMALDEHYDE IN RESINS AND FINISHING BATHS
Lowering formaldehyde emissions from finished textiles and wood-based panels
Acting as a reactive co-component in amino resins
Serving as the base unit of DMEU textile crosslinkers
Serving as an intermediate for DMI and pharmaceutical building blocks
Acting as a polar, water-soluble reactive intermediate in specialty chemistry
The effectiveness of Imidazolidin-2-one depends on pH, temperature, the ratio of scavenger to formaldehyde, the resin type and the curing conditions. Too much scavenger in a resin can slow curing, reduce bonding strength or change the finish properties, so the dose must be optimized for each system.
IMIDAZOLIDIN-2-ONE AS A FORMALDEHYDE SCAVENGER IN TEXTILES AND WOOD PANELS
TEXTILE FINISHING
Easy-care and wrinkle-resistant finishes on cotton and cotton blends are often based on N-methylol resins such as DMDHEU and its modified forms. These finishes can release formaldehyde from the fabric. Ethyleneurea can be added to the finishing bath or used in an after-treatment to bind free and loosely bound formaldehyde and help finished goods meet the formaldehyde limits of eco-labels and retailer standards.
UREA-FORMALDEHYDE AND MELAMINE-UREA-FORMALDEHYDE ADHESIVES
In particleboard, MDF and plywood production, UF and MUF resins are the main adhesives. The cyclic urea can be added as an internal additive to the resin or glue mix. Reported addition levels are commonly around 5–10 % by weight relative to resin solids, but the optimum depends on the resin's formaldehyde-to-urea ratio and the target emission class.
SURFACE POST-TREATMENT OF PANELS
Aqueous scavenger solutions containing Imidazolidin-2-one can be sprayed onto hot or cooled panels after pressing to reduce surface emissions. Commercial scavenger concentrates for this purpose are reported in the range of about 10–40 % active content.
POINTS TO CONSIDER IN THESE APPLICATIONS:
SCAVENGER DOSE RELATIVE TO RESIN SOLIDS OR FREE FORMALDEHYDE CONTENT
Effect on gel time and curing speed of the resin
Effect on internal bond strength and swelling of panels
Effect on fabric handle, strength retention and wrinkle recovery in textiles
Compatibility with catalysts and other bath components
Measurement method for formaldehyde emission (for example chamber, desiccator, perforator or textile extraction methods)
IMIDAZOLIDIN-2-ONE AS A CHEMICAL INTERMEDIATE
Beyond scavenging, Imidazolidin-2-one is an important intermediate.
DMEU TEXTILE RESINS
Reaction of Imidazolidin-2-one with two moles of formaldehyde gives 1,3-bis(hydroxymethyl)imidazolidin-2-one, known as dimethylol ethyleneurea (DMEU). DMEU was one of the first cyclic urea crosslinkers for durable press finishing of cotton.
DMI SOLVENT
1,3-Dimethyl-2-imidazolidinone (DMI) is a high-boiling, polar aprotic solvent used in polymer chemistry and organic synthesis. The formaldehyde scavenger is a key building block for its production.
PHARMACEUTICAL INTERMEDIATES
Ethyleneurea is used to prepare activated derivatives such as 2-oxoimidazolidine-1-carbonyl chloride, which are building blocks for the acylureido penicillins azlocillin and mezlocillin, and it serves as a scaffold for other substituted imidazolidinones in medicinal chemistry.
OTHER SPECIALTY CHEMICALS
The cyclic urea can be used in the synthesis of other heterocycles, agrochemical intermediates, rubber and leather auxiliaries and fragrance-related compounds.
IN WHICH SECTORS IS IMIDAZOLIDIN-2-ONE USED?
MAIN AREAS OF USE:
TEXTILE FINISHING (FORMALDEHYDE SCAVENGING, EASY-CARE RESIN CHEMISTRY)
Wood-based panels (particleboard, MDF, plywood)
Urea-formaldehyde and melamine-urea-formaldehyde adhesives
Paper and coating resins
Leather and rubber auxiliaries
Fragrance applications
Pharmaceutical intermediates
Fine and specialty chemical synthesis
Solvent production (DMI)
Laboratory and analytical standards
The textile and wood industries mostly use technical grades (hemihydrate or solutions) and focus on active content, dosing convenience and price. Pharmaceutical and fine chemical producers require high-purity anhydrous material with controlled impurities and complete documentation.
IS IMIDAZOLIDIN-2-ONE USED IN COSMETIC, FOOD, AND PHARMACEUTICAL APPLICATIONS?
Cosmetics: Imidazolidin-2-one is listed in the EU CosIng inventory with the function perfuming. It is not a common cosmetic ingredient, and any use in cosmetics requires a suitable grade and a safety assessment of the finished product according to the cosmetic legislation of the target market.
Food: Imidazolidin-2-one is not a food additive and has no E number. It is mainly relevant in food analysis as a degradation product of ETU from dithiocarbamate fungicide residues. Technical grades should not be used in food or food contact applications.
Pharmaceuticals: Imidazolidin-2-one is not an active ingredient or excipient in finished medicines, but it is an intermediate in the synthesis of certain active pharmaceutical ingredients. For this use, high-purity grades with appropriate quality documentation are required.
INDUSTRIAL APPLICATIONS OF IMIDAZOLIDIN-2-ONE
LOW-FORMALDEHYDE TEXTILE FINISHING
Purpose: To reduce formaldehyde release from easy-care fabrics.
Role of Imidazolidin-2-one: Scavenger in finishing baths or after-treatments, base unit of DMEU-type resins.
Performance effect: Lower free and releasable formaldehyde on fabric.
Limitations: Can influence crease recovery, handle and strength, dose must be balanced with finish performance.
WOOD-BASED PANEL ADHESIVES
Purpose: To reduce formaldehyde emissions from particleboard, MDF and plywood.
Role of Imidazolidin-2-one: Internal additive in UF/MUF resins or component of surface post-treatment solutions.
Performance effect: Lower emission values.
Limitations: Excess scavenger can slow curing and reduce internal bond strength, press time and resin formulation may need adjustment.
SPECIALTY SYNTHESIS
Purpose: To produce DMI, pharmaceutical intermediates and other heterocycles.
Role of Imidazolidin-2-one: Reactive cyclic urea building block.
Limitations: Requires high-purity grades and controlled reaction conditions.
AUXILIARY USES
In leather, rubber and coating auxiliaries, Imidazolidin-2-one is used as a reactive additive and formaldehyde-binding component in systems that contain formaldehyde-based resins.
WHICH PROBLEMS CAN IMIDAZOLIDIN-2-ONE HELP SOLVE?
EXCESS FREE FORMALDEHYDE IN FINISHED TEXTILES
Easy-care finishes may exceed formaldehyde limits set by eco-labels or customers. Adding Imidazolidin-2-one to the finishing process can help bring formaldehyde values down.
HIGH EMISSION CLASS OF WOOD PANELS
Panels made with UF adhesives may not meet the required emission class. Imidazolidin-2-one used internally or as a surface treatment can help reduce emissions, together with resin and process optimization.
ODOR OF FORMALDEHYDE IN RESINS AND AUXILIARIES
Free formaldehyde causes odor during processing and in finished goods. Scavenging with Imidazolidin-2-one reduces this odor.
NEED FOR A REACTIVE CYCLIC UREA BUILDING BLOCK
In synthesis, Imidazolidin-2-one offers a cheap, stable and well-defined cyclic urea for producing DMI, DMEU and pharmaceutical intermediates.
The formaldehyde scavenger is not a substitute for proper resin selection and curing. The best results are achieved when the scavenger is part of an optimized overall system.
THINGS TO CONSIDER WHEN USING IMIDAZOLIDIN-2-ONE
A common mistake is to dose Imidazolidin-2-one without considering its effect on curing. Because it reacts with formaldehyde and methylol groups, it also competes with the crosslinking reactions that give resins and finishes their strength.
POINTS TO CONSIDER:
CONFIRM WHETHER THE PRODUCT IS ANHYDROUS, HEMIHYDRATE OR SOLUTION, AND CALCULATE THE DOSE ON AN ACTIVE BASIS.
Optimize the dose for each resin or finishing recipe.
Monitor gel time, curing speed and bond strength in adhesive systems.
Monitor crease recovery, tensile and tear strength and handle in textile finishes.
Check the pH of baths and resins, since the reactions are pH dependent.
Use a reliable formaldehyde test method appropriate to the product and market.
Store the product dry and tightly closed.
Avoid contact with strong oxidizing agents and strong acids during storage.
Avoid dust formation when handling the powder.
Use eye protection and gloves.
Ethyleneurea is classified by suppliers as an irritant: supplier safety data sheets list serious eye irritation, and depending on the supplier also skin irritation, respiratory irritation or possible organ damage through prolonged or repeated exposure. Dust should be avoided, and handling should be done with safety glasses or goggles, protective gloves and adequate ventilation.
INITIAL FORMULATION APPROACHES FOR IMIDAZOLIDIN-2-ONE
The examples below are laboratory starting points for evaluating Imidazolidin-2-one. They are not validated industrial recipes. Resin type, fabric, panel construction and process conditions can strongly influence the outcome, so each trial must be adapted and checked for performance, emissions and safety.
The added percentage compositions are illustrative laboratory starting mixtures (% w/w), not validated industrial recipes. Each totals 100 % on the stated basis. Active scavenger is calculated as anhydrous ethyleneurea, correct for the actual product assay and rebalance water.
EXAMPLE 1: IMIDAZOLIDIN-2-ONE AS AN INTERNAL SCAVENGER IN A UF PARTICLEBOARD RESIN
Objective: To determine the effect of Imidazolidin-2-one level on free formaldehyde, gel time, internal bond strength and formaldehyde emission of laboratory particleboard.
INITIAL COMPONENTS:
UF RESIN: CONSTANT TYPE AND SOLIDS CONTENT
Imidazolidin-2-one (active basis): approx. 0, 2.5, 5, 7.5 and 10 % by weight on resin solids
Hardener (e.g. ammonium sulfate or other latent catalyst): constant
Wax emulsion: constant
Wood particles: constant moisture and size distribution
APPLICATION APPROACH:
Imidazolidin-2-one is dissolved in water and added to the resin shortly before glue mixing.
Free formaldehyde of the resin mix and gel time at a fixed temperature are measured.
Particles are blended with the glue mix, formed into mats and pressed under constant conditions.
Board density, internal bond strength, thickness swelling and formaldehyde emission are measured with an appropriate standard method.
The Imidazolidin-2-one level giving the best balance between emission and mechanical properties is selected.
Dust and formaldehyde exposure should be controlled during resin handling and pressing.
ILLUSTRATIVE GLUE-MIX COMPONENTS FOR THE 5 % SCAVENGER-ON-RESIN-SOLIDS TRIAL (% W/W)
UF resin solution (65 % solids): 80.00 %
Imidazolidin-2-one (100 % active basis): 2.60 %
Hardener solution (20 % active): 2.00 %
Wax emulsion (50 % solids): 1.00 %
Water: 14.40 %
Total: 100.00 %
The resin contributes 52 % solids, so 2.60 % scavenger equals 5 % on resin solids. For the 0, 2.5, 7.5 and 10 % trial levels, use respectively 0, 1.30, 3.90 and 5.20 % active scavenger and 17.00, 15.70, 13.10 and 11.80 % water. Wood particles are outside this glue-mix basis, confirm hardener identity and dosage with the resin supplier.
EXAMPLE 2: IMIDAZOLIDIN-2-ONE IN A LOW-FORMALDEHYDE EASY-CARE COTTON FINISH
Objective: To investigate how Imidazolidin-2-one in the finishing bath affects free formaldehyde on fabric and the easy-care performance of a DMDHEU-type finish.
INITIAL APPROACH:
N-METHYLOL CROSSLINKING RESIN (E.G. MODIFIED DMDHEU): CONSTANT LEVEL
Catalyst (e.g. magnesium chloride based): constant level
Imidazolidin-2-one (active basis): approx. 0, 5, 10 and 15 % relative to resin solids
Softener and wetting agent: constant
Fabric: 100 % cotton, constant construction
APPLICATION APPROACH:
The finishing bath is prepared and Imidazolidin-2-one is dissolved in it.
Fabric is padded at constant wet pick-up, dried and cured under constant conditions.
Free formaldehyde on fabric is measured with a standard textile method.
Wrinkle recovery angle, durable press rating, tensile and tear strength and handle are evaluated.
Results are compared to find the scavenger level that meets the formaldehyde target with the smallest loss in finish performance.
ILLUSTRATIVE FINISHING-BATH COMPONENTS FOR THE 10 % SCAVENGER-ON-RESIN-SOLIDS TRIAL (% W/W)
Modified DMDHEU resin solution (50 % solids): 10.00 %
Catalyst preparation (30 % active): 1.00 %
Imidazolidin-2-one (100 % active basis): 0.50 %
Softener preparation: 1.00 %
Wetting-agent preparation: 0.20 %
Water: 87.30 %
Total: 100.00 %
The resin contributes 5 % solids. For the 0, 5 and 15 % scavenger-on-resin-solids trials, use respectively 0, 0.25 and 0.75 % active scavenger and 87.80, 87.55 and 87.05 % water. Catalyst and auxiliary amounts are illustrative and must be confirmed for the selected products, fabric is outside this bath basis.
EXAMPLE 3: SURFACE POST-TREATMENT OF PANELS WITH IMIDAZOLIDIN-2-ONE SOLUTION
Objective: To evaluate the effect of an aqueous Imidazolidin-2-one spray on the surface formaldehyde emission of finished panels.
INITIAL APPROACH:
Imidazolidin-2-one solution: approx. 10, 20 and 30 % active content
Application quantity: screened at several levels (g/m²)
Panel temperature at application: hot from the press and cooled, compared
APPLICATION APPROACH:
THE SOLUTION IS SPRAYED EVENLY ON BOTH PANEL SURFACES.
Panels are conditioned under standard climate.
Formaldehyde emission, surface appearance and suitability for subsequent lamination or painting are evaluated.
The application level and panel temperature giving the best emission reduction without surface defects are selected.
Spray mist should be controlled and eye protection used during application.
ILLUSTRATIVE INITIAL SPRAY-SOLUTION COMPONENTS (% W/W)
Imidazolidin-2-one (100 % active basis): 20.00 %
Water: 80.00 %
Total: 100.00 %
For the 10 and 30 % active trials, use respectively 10 and 30 % active scavenger and 90 and 70 % water. If using hemihydrate or a purchased solution, calculate the as-supplied amount from its actual assay, a dilute supplied solution cannot produce a higher active level by dilution alone.
IMIDAZOLIDIN-2-ONE SIMILAR PRODUCTS AND ALTERNATIVES
Imidazolidin-2-one and urea
Urea is the most common and cheapest formaldehyde scavenger in UF resins. The cyclic urea is more expensive but forms more stable adducts and is preferred where long-term reduction of formaldehyde release is important.
Imidazolidin-2-one and melamine
Melamine is used in MUF resins to improve water resistance and reduce emissions. It changes the resin system more fundamentally than a scavenger such as Imidazolidin-2-one.
Imidazolidin-2-one and other scavengers
Sodium bisulfite, ammonium salts, hydrazides, carbohydrazide and some amines can also bind formaldehyde. Each has different effects on pH, curing and odor.
Imidazolidin-2-one and formaldehyde-free systems
In textiles, formaldehyde-free crosslinkers such as polycarboxylic acids (for example citric acid or BTCA) and non-formaldehyde DMDHEU derivatives avoid formaldehyde altogether. In wood panels, pMDI, soy-based and other formaldehyde-free adhesives are alternatives.
Imidazolidin-2-one and DMI
DMI is a derivative of Imidazolidin-2-one used as a solvent, not as a scavenger. The two are not interchangeable.
The choice should be confirmed through laboratory and production trials and the applicable emission tests.
QUALITY CONTROL AND PURCHASING CRITERIA FOR IMIDAZOLIDIN-2-ONE
RECOMMENDED INFORMATION TO REVIEW BEFORE PURCHASING:
PRODUCT FORM (ANHYDROUS, HEMIHYDRATE, SOLUTION)
CAS number matching the product form
Active content (calculated as anhydrous Imidazolidin-2-one)
Purity (GC or nitrogen-based assay)
Water content
Melting point
Appearance and color
pH of a defined solution
Residual ethylenediamine and urea
Ash
Technical Data Sheet (TDS)
Safety Data Sheet (SDS)
Certificate of Analysis (COA)
Batch number and production date
Packaging and net quantity
Storage conditions and shelf life
REACH registration status
The COA confirms the analysis of a specific batch, the TDS describes the grade and its intended use, and the SDS covers hazards and safe handling. For pharmaceutical synthesis, impurity profiles and additional quality documentation may be required.
STORAGE AND HANDLING OF IMIDAZOLIDIN-2-ONE
The formaldehyde scavenger should be stored in tightly closed original containers in a cool, dry, well-ventilated place, protected from moisture and heat. Recommended storage is at room temperature, preferably in a cool and dark place.
The solid can absorb moisture and cake. Containers should be closed after each use, and dust formation should be avoided during handling and transfer.
Ethyleneurea should be kept away from strong oxidizing agents and strong acids, and away from formaldehyde-containing products unless used in a controlled process.
Typical shelf life is given by suppliers as around 24 months for crystal grades and around 12 months for aqueous solutions under proper storage conditions.
Transport: Imidazolidin-2-one is generally not classified as dangerous goods for transport. For the current transport classification of the supplied grade, please contact Ataman Kimya.
In case of spillage, the solid should be collected mechanically with minimal dust formation and placed in suitable containers. Solutions should be absorbed with inert material. Release to drains and water should be prevented.
SAFETY INFORMATION OF IMIDAZOLIDIN-2-ONE
Hazard classification: Supplier safety data sheets classify Imidazolidin-2-one with the signal word "Warning". Listed hazards include serious eye irritation (H319) and, depending on the supplier and form, skin irritation (H315), respiratory irritation (H335) or may cause damage to organs through prolonged or repeated exposure (H373).
Eyes: Eye contact causes irritation. Rinse cautiously with water for several minutes, remove contact lenses if easy to do, and seek medical advice if irritation persists.
Skin: Wash with soap and water. Remove contaminated clothing.
Inhalation: Avoid inhaling dust. Move to fresh air if irritation occurs.
Ingestion: Rinse mouth, seek medical advice if discomfort occurs.
Fire: Imidazolidin-2-one is a combustible solid with a high flash point. Suitable extinguishing media are water spray, foam, dry chemical and carbon dioxide. Combustion produces carbon oxides and nitrogen oxides.
Personal protection: Safety glasses or goggles, protective gloves, suitable work clothing and dust protection where dust is generated.
Environment: Avoid release to drains, soil and surface water.
Waste: Dispose of according to local regulations.
WHAT SHOULD BE CONSIDERED WHEN BUYING IMIDAZOLIDIN-2-ONE?
BEFORE PURCHASING, THE FOLLOWING INFORMATION SHOULD BE CLARIFIED:
APPLICATION (TEXTILE, WOOD PANEL, RESIN, PHARMACEUTICAL SYNTHESIS, OTHER)
Required form (anhydrous, hemihydrate, solution)
Required active content and purity
Specific impurity limits for pharmaceutical or fine chemical use
Required quantity and packaging (bags, drums, IBC)
Documentation needs (TDS, SDS, COA, REACH)
Current product specification if replacing another scavenger
The price of Imidazolidin-2-one depends on the cost of ethylenediamine and urea, energy, purity and form, order volume, packaging and logistics.
SUPPLY OF IMIDAZOLIDIN-2-ONE FROM ATAMAN KIMYA
The cyclic urea is a cyclic urea used mainly as a formaldehyde scavenger and chemical intermediate in the textile, wood, resin and specialty chemical industries. Companies planning to purchase it should define the required form, active content and documentation in advance.
Ataman Kimya can provide information on available forms, specifications, packaging and price quotations for Imidazolidin-2-one.
Current stock, origin and specification details should be confirmed with Ataman Kimya before ordering.
SHARING THE FOLLOWING INFORMATION HELPS PREPARE A QUOTATION FOR IMIDAZOLIDIN-2-ONE:
APPLICATION AND TARGET MARKET
Required form and active content
Required purity and impurity limits
Estimated quantity
Packaging preference
Required documents
FREQUENTLY ASKED QUESTIONS ABOUT IMIDAZOLIDIN-2-ONE
WHAT IS IMIDAZOLIDIN-2-ONE?
Imidazolidin-2-one, also called ethyleneurea or 2-imidazolidinone, is a five-membered cyclic urea used mainly as a formaldehyde scavenger and as an intermediate in textile, resin and pharmaceutical chemistry.
WHAT IS THE CAS NUMBER OF IMIDAZOLIDIN-2-ONE?
The CAS number is 120-93-4 for the anhydrous form and 121325-67-5 for the hemihydrate.
WHAT IS THE EC NUMBER OF IMIDAZOLIDIN-2-ONE?
The EC number is 204-436-4.
WHAT IS THE CHEMICAL FORMULA OF IMIDAZOLIDIN-2-ONE?
The formula is C3H6N2O and the molecular weight is 86.09 g/mol.
IS ETHYLENEUREA THE SAME AS IMIDAZOLIDIN-2-ONE?
Yes. Ethyleneurea and 2-imidazolidinone are common names for Imidazolidin-2-one.
WHAT IS THE DIFFERENCE BETWEEN ETHYLENEUREA AND ETHYLENETHIOUREA (ETU)?
In ethyleneurea, the ring carbon carries an oxygen (C=O), in ethylenethiourea it carries a sulfur (C=S). They are different substances with different uses and hazards. Ethyleneurea is a degradation product of ETU.
HOW DOES IMIDAZOLIDIN-2-ONE REMOVE FORMALDEHYDE?
Its N–H groups react with formaldehyde and with N-methylol groups to form stable adducts, lowering free formaldehyde and emissions.
HOW MUCH IMIDAZOLIDIN-2-ONE IS USED IN UF RESINS?
Reported internal levels are commonly around 5–10 % by weight on resin solids, but the optimum must be determined by trials.
WHAT IS DMEU?
DMEU (dimethylol ethyleneurea) is formed by the reaction of Imidazolidin-2-one with formaldehyde and is used as a crosslinking agent in cotton finishing.
IS IMIDAZOLIDIN-2-ONE SOLUBLE IN WATER?
Yes, it is very soluble in water (approx. 950 g/L at 20 °C) and also soluble in methanol.
WHAT IS THE MELTING POINT OF IMIDAZOLIDIN-2-ONE?
About 129–132 °C for the anhydrous form and about 58 °C for the hemihydrate.
IS IMIDAZOLIDIN-2-ONE USED IN PHARMACEUTICALS?
It is used as an intermediate, for example in the synthesis of the side chains of azlocillin and mezlocillin, but not as an excipient in finished medicines.
IS IMIDAZOLIDIN-2-ONE USED IN COSMETICS?
It is listed in CosIng with the function perfuming, but it is not a common cosmetic ingredient.
IS IMIDAZOLIDIN-2-ONE HAZARDOUS?
It is classified as an irritant, mainly causing serious eye irritation, some suppliers also list skin and respiratory irritation or organ effects after repeated exposure.
IS IMIDAZOLIDIN-2-ONE A PESTICIDE?
No. It is a degradation product of ETU from dithiocarbamate fungicides, but it is not used as a pesticide.
WHAT IS THE UN NUMBER OF IMIDAZOLIDIN-2-ONE?
It is generally not classified as dangerous goods for transport. For the classification of the supplied grade, please contact Ataman Kimya.
HOW SHOULD IMIDAZOLIDIN-2-ONE BE STORED?
In tightly closed containers in a cool, dry and well-ventilated place, away from moisture, strong oxidizing agents and strong acids.
IS THERE AN ALTERNATIVE TO IMIDAZOLIDIN-2-ONE?
Urea, melamine, sodium bisulfite, hydrazides and formaldehyde-free crosslinkers can be alternatives depending on the application.
WHAT DOCUMENTS SHOULD BE REQUESTED WHEN BUYING IMIDAZOLIDIN-2-ONE?
TDS, SDS and COA, together with REACH information and, for pharmaceutical use, impurity and quality documentation.
WHAT TECHNICAL SPECIFICATIONS ARE IMPORTANT WHEN BUYING IMIDAZOLIDIN-2-ONE?
Form, active content, purity, water content, melting point, pH, residual raw materials and appearance.
IMIDAZOLIDIN-2-ONE – TECHNICAL SUMMARY
Imidazolidin-2-one (ethyleneurea, 2-imidazolidinone, CAS 120-93-4, EC 204-436-4, C3H6N2O, 86.09 g/mol) is a white, highly water-soluble cyclic urea with a melting point of about 129–132 °C. It is also supplied as a hemihydrate (CAS 121325-67-5) and as aqueous solutions.
Its N–H groups react with formaldehyde and N-methylol groups, which makes it an effective formaldehyde scavenger in textile finishing, UF and MUF adhesives and wood panel post-treatment, and a building block for DMEU resins, DMI solvent and pharmaceutical intermediates.
It should not be confused with ethylenethiourea, DMI, DMEU or 1-(2-aminoethyl)imidazolidin-2-one, which are different substances.
Supplier safety data sheets classify it with "Warning", mainly for serious eye irritation, with some suppliers also listing skin or respiratory irritation or organ effects after repeated exposure. It should be handled with eye protection, gloves and dust control.
Companies planning to source Imidazolidin-2-one through Ataman Kimya are advised to share their application, required form and active content, quantity and documentation needs to confirm current product, stock, origin, packaging and quotation details.
The formaldehyde scavenger can be sourced from ATAMAN KİMYA. For further information and supply inquiries about Imidazolidin-2-one, please contact ATAMAN KİMYA.
