MDEA METHYLDIETHANOLAMINE

CAS Number: 105-59-9
EC Number: 203-312-7
Molecular Formula: C5H13NO2
Molecular Weight: 119.16 g/mol
Boiling Point: Representative 243–248 °C at 760 mmHg for the concentrated material; commercial distillation specifications may use a broader interval.
Melting Point: Approximately −21 °C for the concentrated material; water and other components alter freezing behavior.
Viscosity: Representative dynamic viscosity 101 mPa·s at 20 °C for concentrated MDEA.
Density: Approximately 1.04 g/cm3 near room temperature; one published technical-grade specification gives relative density of 1.038–1.044 at 20/20 °C.

COMMON PRODUCT AND CHEMICAL NAMES

MDEA Methyldiethanolamine
Methyldiethanolamine
N-Methyldiethanolamine
Methyl diethanolamine
N-Methyl diethanolamine
MDEA
MDEOA
2,2′-(Methylimino)diethanol
N,N-Bis(2-hydroxyethyl)methylamine
Bis(2-hydroxyethyl)methylamine
Ethanol, 2,2′-(methylimino)bis-

WHAT IS MDEA METHYLDIETHANOLAMINE?

MDEA Methyldiethanolamine is a low-molecular-weight amino alcohol with a tertiary nitrogen center and two primary hydroxyl groups. These functional groups give the molecule more than one useful role: it can act as a base, participate in selected catalytic systems and supply hydroxyl functionality for chemical reactions.
The MDEA Methyldiethanolamine molecule therefore appears in different industrial contexts. In gas treatment, its protonation and acid-gas equilibrium behavior are central; in a polyurethane, the hydroxyl groups can become chemically incorporated into the polymer; in a coating neutralization system, its effect on resin ionization and solution behavior is important.
The name MDEA Methyldiethanolamine does not specify an aqueous concentration or an activated formulation. Physical data in this profile refer to concentrated MDEA where stated, while gas-treatment performance must be assessed for the complete circulating solvent.
Pure MDEA, a solution made by diluting it with water and a proprietary promoted blend should not be treated as interchangeable products merely because all contain CAS Number 105-59-9.

CAS NUMBER, EC NUMBER AND CHEMICAL IDENTIFICATION

CAS Number 105-59-9 and EC Number 203-312-7 identify N-methyldiethanolamine. The formula C5H13NO2 corresponds to a molecular weight of approximately 119.16 g/mol.
MDEA is distinct from monoethanolamine, diethanolamine, triethanolamine, dimethylethanolamine and N-methylethanolamine. Differences in nitrogen substitution and hydroxyl functionality affect basicity, acid-gas reaction pathways, volatility and chemical reactivity.
The letter N in N-methyldiethanolamine identifies the position of the methyl group on nitrogen. The two hydroxyethyl groups remain attached to the same nitrogen center, so MDEA is a tertiary amine despite containing two alcohol groups.
For a solution or activated blend, the SDS and specification must identify the relevant water content and additional components. The molecular weight of MDEA remains 119.16 g/mol, but the mixture itself does not have one fixed molecular formula or molecular weight.

CHEMICAL STRUCTURE AND MOLECULAR CHARACTERISTICS

The nitrogen lone pair of MDEA Methyldiethanolamine provides a site for proton acceptance. When MDEA reacts with an acid through neutralization, the nitrogen becomes protonated and the corresponding counterion is present in the solution.
The absence of an N–H bond is especially important in gas treatment. MDEA does not follow the same conventional direct carbamate-forming pathway available to primary and secondary amines, so its aqueous carbon dioxide chemistry and absorption kinetics differ from those of MEA or DEA.
The hydroxyl groups of MDEA Methyldiethanolamine provide hydrogen-bonding sites and contribute to water miscibility. They also give MDEA a diol function in suitable chemical reactions, including polyurethane formation, where hydroxyl reactivity must be distinguished from nitrogen basicity.
Calling MDEA a tertiary amine does not mean that the whole molecule is chemically inert. The basic center of MDEA Methyldiethanolamine, hydroxyl groups and interactions with water or acidic components must all be considered when selecting a formulation or processing system.

PHYSICAL AND CHEMICAL PROPERTIES

The following values distinguish representative physical data, theoretical functional-group calculations and an example of a published technical-grade specification. They are not a unified specification guaranteed by Ataman Kimya, and concentrated-material values must not be substituted for an unspecified aqueous solution or activated blend.
Physical State: Liquid near room temperature.
Appearance: Clear, colorless to pale-yellow liquid; color limits are grade dependent.
Odor: Characteristic amine or ammoniacal odor; odor is not a reliable indicator of a safe exposure level.
Molecular Formula: C5H13NO2.
Molar Mass: Approximately 119.16 g/mol.
Tertiary Amine Groups: One per molecule.
Primary Hydroxyl Groups: Two per molecule.
Nitrogen-Bound Hydrogen Atoms: None in the neutral MDEA molecule.
Representative Boiling Range: 243–248 °C at 760 mmHg in a September 2025 SDS.
Representative Freezing or Melting Point: Approximately −21 °C for concentrated MDEA.
Representative Dynamic Viscosity: 101 mPa·s at 20 °C, equivalent to 101 cP.
Approximate Liquid Density: About 1.04 g/cm3 near room temperature; retain the actual temperature and method for process calculations.
Representative Relative Density Specification: 1.038–1.044 at 20/20 °C in one published technical-grade specification. This is dimensionless and referenced to water at 20 °C, rather than a density reported directly in g/cm3.
Refractive Index: Representative nD20 of 1.4694.
Water Solubility: Completely miscible for MDEA; this does not establish the phase behavior of every contaminated process solution.
Hygroscopicity: Absorbs moisture from the surrounding atmosphere; water content must be controlled during storage and sampling.
Representative Aqueous pH: 11.5 at 100 g/L in the reviewed SDS; the listed entry does not provide a measurement temperature.
Alternative Dilute-Solution pH Reference: Greater than 10 for a 0.1 N aqueous solution in published technical information; this is a different concentration basis and should not be compared as the same test.
Basicity: A published amine-selection guide reports a representative conjugate-acid pKa of 8.52. Temperature and solution conditions affect this value; it is not the dissociation constant of an alcohol group.
Theoretical Amine Equivalent Weight: 119.16 g per equivalent, assuming one titratable tertiary amine center per pure molecule.
Theoretical Amine Number: Approximately 470.8 mg KOH/g for pure MDEA, calculated from one basic equivalent per molecule; the actual result depends on assay, impurities and titration method.
Theoretical Hydroxyl Equivalent Weight: Approximately 59.58 g per hydroxyl equivalent, assuming two hydroxyl groups per molecule.
Theoretical Hydroxyl Number: Approximately 941.7 mg KOH/g for pure MDEA, calculated from two hydroxyl equivalents; this is not an independently measured release specification.
Representative Vapor Pressure: 0.026 mbar at 40 °C in the reviewed SDS, equivalent to 2.6 Pa.
Representative Relative Vapor Density: Approximately 4.0, with air = 1; actual exposure depends on temperature, mist generation and ventilation.
Representative Flash Point: 137 °C in the reviewed September 2025 SDS, with no test method specified in that entry. Use the current grade-specific method and value for hazard assessment.
Representative Partition Coefficient: Reported log Pow of approximately −1.08 in the same SDS; aqueous ionization conditions affect interpretation of distribution behavior.
Representative Technical-Grade Assay: Minimum 99% by GC in one published specification.
Representative Water Limit: Maximum 0.5% by mass in that specification, equivalent to 5000 mg/kg; tighter water limits must be separately agreed where needed.
Representative Color Limit: Maximum 50 APHA units in that specification.
Representative Commercial Distillation Range: 240–260 °C in that specification; the displayed specification does not state the pressure, so it should not replace a pressure-qualified physical boiling range.
Bulk Density: Not applicable as a powder-packing property of the liquid.
Decomposition Temperature: No single verified grade-independent value assigned here; chemical stability depends on temperature, exposure time and the process environment.
Shelf Life: Grade, purity, packaging, storage conditions and manufacturer dependent; follow the supplied material's expiry or retest information.
For an aqueous circulating solvent, concentration, acid-gas loading, temperature and contaminants all influence physical properties. Density, viscosity or pH alone cannot establish a complete solvent composition or distinguish every promoter and degradation product present.

HOW DOES MDEA REMOVE ACID GASES?

In aqueous service, MDEA absorbs hydrogen sulfide through reversible acid–base chemistry. A simplified net equilibrium is MDEA + H2S ⇌ MDEAH+ + HS−, where MDEAH+ represents protonated MDEA.
Carbon dioxide absorption involves water and a different reaction pathway. A useful simplified net representation is MDEA + CO2 + H2O ⇌ MDEAH+ + HCO3−. This describes the overall bicarbonate-based equilibrium without implying that every elementary step occurs in one reaction.
The difference in reaction rates allows an appropriately designed MDEA system to remove H2S selectively while permitting some CO2 to remain in the treated gas. Selectivity is therefore a process outcome, not a claim that MDEA cannot absorb CO2.
Regeneration changes the conditions so that absorbed acid gas is released and the solvent can circulate again. Working capacity depends on the difference between the actual rich and lean solvent loadings, rather than on a theoretical single-molecule stoichiometry alone.

WHICH INDUSTRIES USE MDEA METHYLDIETHANOLAMINE?

Natural-gas processing, oil refining, synthesis-gas treatment and sulfur-recovery operations are major application areas for MDEA-containing solvents. The appropriate solvent may be an unpromoted aqueous amine or a formulated system selected for a specific separation duty.
Other documented users include coating and ink formulators, polyurethane and specialty-resin manufacturers, metalworking-fluid producers and manufacturers of textile-treatment intermediates. Electronics applications use separately qualified high-purity grades with contamination requirements beyond a general industrial assay.
These uses exploit different functions of MDEA Methyldiethanolamine. A gas-treatment grade, an electronic grade and a reactive intermediate for a resin should be selected through their own specifications rather than treated as one universally suitable material.

MDEA IN SELECTIVE H2S REMOVAL FROM NATURAL GAS

Selective H2S removal is a defining application for MDEA. Its rapid acid–base interaction with H2S and slower unpromoted CO2 absorption can be used to meet an H2S target while limiting unnecessary CO2 pickup, where the treated-gas specification permits that approach.
The practical value lies in treating the required components rather than absorbing every available acid-gas molecule. Limiting avoidable CO2 circulation may reduce the amount of acid gas that must be released during regeneration, but the economic result depends on the complete unit.
Absorber contact conditions are central to this behavior. Gas composition, acid-gas partial pressures, solvent condition and mass transfer influence the relative amounts of H2S and CO2 removed; selectivity cannot be predicted from MDEA assay alone.
The gas specification must also be considered as a whole. A solvent choice that achieves a low H2S concentration may still be unsuitable if too much CO2 remains for the downstream process, so H2S selectivity and total acid-gas removal are different objectives.
MDEA should not be represented as a universal solution for all sulfur-containing contaminants. Requirements for other sulfur species and downstream gas quality need separate assessment within the treatment scheme.

MDEA IN REFINERY GAS AND RECYCLE-GAS TREATMENT

MDEA-containing solvents are used in refinery and petrochemical gas-treatment systems where acid-gas removal supports the required gas quality. The feed composition and process connections can differ substantially from a natural-gas service.
For a refinery application, solvent selection should account for the gases and liquids that can enter the amine loop. Hydrocarbon contamination, solids or other carryover may change foaming, solvent loss and hydraulic behavior even when the fresh MDEA meets its purchase specification.
The useful comparison therefore includes both separation performance and solvent management. Track the condition of the circulating solution, the treated-gas result and the effect on regeneration rather than assuming that a higher fresh-amine concentration will correct every operating problem.
Changes from another amine to MDEA require an engineering assessment of the existing unit. Circulation equipment, contacting devices, heat exchange, regeneration and materials of construction determine whether the potential advantages of MDEA Methyldiethanolamine can be used effectively.

ACTIVATED MDEA FOR CARBON DIOXIDE REMOVAL

Unpromoted MDEA's slower CO2 absorption can limit performance when deep or rapid CO2 removal is required. Activated or promoted systems combine MDEA with additional components that improve the relevant reaction and mass-transfer behavior.
Piperazine is a documented promoter in MDEA research and process technology. The blend has reaction pathways and physical properties that differ from those of MDEA alone, so it should be treated as a formulated solvent rather than as a higher-purity version of the same neat chemical.
An activated system can be selected for duties in which CO2 removal is the main objective, including appropriately designed synthesis-gas and cryogenic-gas-processing applications. The promoter package, total solvent composition and operating envelope must match the actual duty.
The terms activated MDEA and formulated MDEA do not establish a standard recipe. Different promoted blends can have different compositions, loading behavior, viscosity and handling requirements, and a performance claim from one blend must not be assigned automatically to another.
For development or replacement work, obtain data for the full solvent and assess it in an appropriate process model or trial. No universal promoter percentage, circulation rate or CO2 outlet guarantee is specified here.

MDEA SYSTEMS IN HYDROGEN, AMMONIA AND CRYOGENIC GAS PROCESSING

Formulated MDEA-based solvents are documented for CO2 removal in hydrogen production, ammonia manufacture and cryogenic gas processing. These applications illustrate why the required gas specification must drive solvent selection rather than a general preference for H2S selectivity.
In synthesis-gas treatment, the CO2-removal duty must be assessed together with the composition and requirements of downstream operations. A system selected for deep CO2 removal may therefore use a different MDEA formulation from one selected to leave part of the CO2 in a natural-gas stream.
Cryogenic processing places particular importance on the components that could interfere with low-temperature operation. The necessary removal target and the chosen solvent technology require process-specific validation rather than an assumption that neat MDEA alone provides the required purification.
These uses also depend on solvent cleanliness and control of carryover. Product assay is an incoming-quality measure, while the condition of the circulating solvent and the actual treated gas determine ongoing unit performance.

MDEA IN TAIL-GAS TREATMENT AND ACID-GAS ENRICHMENT

Selective MDEA-based solvents are used in sulfur-recovery tail-gas treatment. Their role is to absorb H2S under the conditions established by the complete treatment system, including any upstream conversion of other sulfur species.
The solvent does not replace the rest of the tail-gas process. Pretreatment, contacting, regeneration and the downstream handling of the recovered acid gas all influence the final sulfur-removal result.
Selectivity can also be useful where the objective is an H2S-richer acid-gas stream rather than maximum CO2 absorption. The separation must be evaluated for the actual feed and sulfur-recovery requirements; the term enrichment does not imply a fixed composition produced by every MDEA unit.
Commercial tail-gas solvents may be specially formulated for low-pressure or stringent outlet duties. Their performance claims belong to the identified formulation and operating design, not to every supply of general-purpose MDEA.

SOLVENT CONDITION, REGENERATION AND SERVICE LIFE

MDEA is used in a circulating treatment loop rather than consumed as a simple once-through scavenger in its principal regenerative applications. This makes working capacity, regeneration and solvent condition important parts of the technical evaluation.
A lower reaction-energy requirement can be advantageous relative to some alternative amine systems, but total reboiler duty includes more than reaction heat. Water circulation, sensible heating, acid-gas loading and the unit configuration also affect the energy balance.
Contaminants can change that balance. Published field research on glycol contamination in an MDEA loop shows that the condition of the solvent can affect acid-gas removal and regeneration demand, supporting the need to distinguish fresh-product properties from circulating-solution performance.
Useful monitoring may include amine concentration, acid-gas loading, degradation products, heat-stable salts, solids, metals and hydrocarbon contamination according to the process. No single pH or color reading replaces a complete solvent-condition assessment.
Corrosion behavior is also system dependent. Describing MDEA as relatively low-corrosion in an appropriate service does not establish that every loaded or degraded solution is noncorrosive to every material.

MDEA IN METALWORKING FLUIDS

MDEA is documented as a pH buffer and anticorrosion component in metalworking fluids. The basic nitrogen center of MDEA Methyldiethanolamine contributes to neutralization and alkaline reserve, while its water compatibility helps support use in suitable aqueous formulations.
Buffering and initial pH are different characteristics. A fluid can have an acceptable starting pH yet respond poorly to acidic contamination, so formulation work should consider the reserve available over the intended operating range.
The anticorrosion contribution must be assessed for the metals and formulation involved. Steel, aluminum alloys and copper-containing materials can respond differently, making a single broad statement such as protects all metals inappropriate.
MDEA should also not be treated as a complete metalworking-fluid package. Lubricity, emulsification, hard-water response, foam and microbiological protection depend on the other ingredients and the diluted working fluid.
Avoid unvalidated combinations with nitrites or other nitrosating agents. The tertiary-amine designation alone is not a basis for declaring a formulation free of nitrosamine-related concerns, particularly when impurities or degradation pathways may be relevant.

MDEA AS A NEUTRALIZER IN COATINGS AND INKS

MDEA can neutralize acidic resin groups in suitable coating and ink systems. Converting part of those groups to an ionic form can improve resin solubility or dispersion behavior, depending on the resin architecture and solvent system.
The required neutralization level should follow the resin's acid functionality and the intended formulation behavior. A pH target alone does not establish the same neutralization state in two chemically different binders.
The relatively low volatility of MDEA Methyldiethanolamine can be useful where a less volatile neutralizing amine is desired. The consequences for drying, retained basic material, water response and film properties must nevertheless be assessed in the complete coating.
Published application information also identifies assistance with pigment dispersion and reduced pH drift in suitable systems. These effects are formulation dependent and should not be described as proof that MDEA replaces a dedicated dispersant or stabilizes every pigment.

MDEA IN TYPE II PHOTOINITIATOR SYSTEMS

Methyldiethanolamine is a documented amine co-initiator for selected Type II photoinitiator combinations used in coatings and inks. Research includes benzophenone/MDEA reference systems for free-radical photopolymerization.
In this role, MDEA Methyldiethanolamine participates in the light-activated initiation system rather than acting simply as an alkaline neutralizer. Performance depends on the paired photoinitiator, the radiation source, resin composition and film conditions.
MDEA is therefore not a universal stand-alone photoinitiator. Substitution into a light-curing formulation requires assessment of cure development and the resulting film rather than assuming that any tertiary amine will behave identically.
Residual low-molecular-weight material and migration can be relevant to the finished coating. Successful curing does not by itself establish suitability for food packaging, skin contact or another regulated exposure.

MDEA IN POLYURETHANES, FOAMS AND ELASTOMERS

MDEA has two hydroxyl groups that can react with isocyanate groups in an appropriately designed polyurethane synthesis. Published manufacturer information identifies its use as a chain extender in selected polyol-based foams and elastomers.
The distinction between the alcohol groups and the tertiary nitrogen is essential. The hydroxyl groups provide the conventional active hydrogens for urethane formation, while the tertiary amine has no N–H bond and can influence the reaction environment through its basicity.
Formulation calculations should therefore use the relevant hydroxyl functionality rather than treating MDEA as a primary-amine hardener. The theoretical hydroxyl equivalent weight of MDEA Methyldiethanolamine is useful for stoichiometric work, but the supplied assay and water content must also be considered.
Water control is particularly important in isocyanate-containing chemistry because water introduces additional reactions and can generate gas. An MDEA grade suitable for an aqueous application is not automatically suitable for moisture-sensitive polymer synthesis.
Final hardness, flexibility, reaction profile and other properties depend on the complete polymer system. MDEA's inclusion alone does not establish a particular cure time, foam structure or mechanical result.

MDEA IN SELECTED EPOXY AND SPECIALTY RESIN SYSTEMS

Documented product information includes MDEA among materials used in selected epoxy-resin and specialty-resin applications. The tertiary amine center of MDEA Methyldiethanolamine can be relevant to catalytic or accelerating functions in an appropriately designed system.
This role should not be confused with a conventional primary- or secondary-amine curing agent that supplies nitrogen-bound active hydrogen. MDEA has no such N–H functionality, so a primary-amine equivalent-weight calculation cannot be transferred to it.
Compatibility, cure response, retained material and final resin properties should be established for the complete formulation. General use in an epoxy technology does not mean that neat MDEA is an interchangeable hardener for every epoxy resin.

MDEA IN TEXTILE-TREATMENT AND SURFACTANT INTERMEDIATES

Textile-treatment uses are documented for MDEA and its derivatives. The combination of a tertiary amine and two hydroxyl groups provides a starting structure for selected salts and chemically modified intermediates used in softener technologies.
Chemical identity must remain clear during these transformations. Neutralizing a tertiary amine with a fatty acid forms a protonated amine salt; it does not by itself create a covalently quaternized ammonium compound.
Esterification or quaternization produces derivatives with different compositions and functions. The properties of a finished softener therefore belong to that derivative and its formulation, rather than to MDEA alone.
For commercial selection, define the intended intermediate or finished treatment and its quality requirements. No universal textile-softener dosage or reaction recipe is assigned to the raw MDEA chemical.

HIGH-PURITY MDEA IN ELECTRONIC PROCESSING

Separately qualified high-purity MDEA grades are documented for stripping, cleaning and wet-etching formulations in semiconductor, display and printed-circuit-board processing. These are formulation applications, not a claim that every industrial MDEA grade is suitable for direct electronic use.
Trace metals and other contamination can be critical in such applications. A high GC assay does not establish a low concentration of every metal, particle or nonvolatile impurity, so the electronic-grade specification must identify the parameters that matter.
The working chemistry also depends on the other formulation components and the materials being processed. Cleaning efficiency, selectivity, residue and compatibility require evaluation on the actual substrate system.
Use the appropriate high-purity documentation and handling controls rather than extending a gas-treatment-grade specification into this application without evidence.

WHAT PROBLEMS CAN MDEA HELP ADDRESS?

In gas treatment, an appropriate MDEA system can help achieve a required H2S/CO2 separation and provide an alternative balance of selectivity, circulation and regeneration to another solvent. A promoted formulation can address a different duty from an unpromoted selective system.
In aqueous industrial formulations, MDEA can help manage acidic components and alkalinity. In selected resins, MDEA Methyldiethanolamine provides hydroxyl functionality or a tertiary-amine contribution that can be used to adjust chemical behavior.
The useful question is which function solves the actual problem. Increasing MDEA concentration is not a general correction for poor contacting, contaminated solvent, an unstable dispersion or an incorrectly balanced curing system.

STARTING FORMULATION AND PROCESS-DEVELOPMENT APPROACHES

For gas treatment, begin with the feed composition, pressure range, treated-gas specifications and available equipment. Select an unpromoted or formulated MDEA solvent through appropriate thermodynamic and rate-based evaluation, supported by the solvent provider's technical information.
For a coating or ink, define the resin acid functionality and the required neutralization or photoinitiator role before selecting an addition level. These functions involve different formulation calculations and should not be combined into a generic amine dosage.
For a polyurethane project, use the hydroxyl equivalent basis and actual material assay, with water included in the overall assessment. For metalworking or cleaning formulations, evaluate the diluted working system rather than only the concentrate.
These are development approaches rather than validated commercial formulas. No unsupported promoter ratio, reboiler temperature, catalyst level, addition sequence or process time is presented as a universal MDEA instruction.

SIMILAR PRODUCTS AND ALTERNATIVES

Monoethanolamine: A primary alkanolamine with different CO2 reaction kinetics, functionality and solvent-selection considerations. Its faster reaction in some duties does not establish lower overall cost in every unit.
Diethanolamine: A secondary alkanolamine that differs from MDEA in carbamate chemistry and other process characteristics. An existing DEA unit requires evaluation before changing solvent.
Triethanolamine: A tertiary alkanolamine with three hydroxyl groups and a different molar mass and basicity. It is not interchangeable with MDEA on a simple equal-weight basis in neutralization or polymer synthesis.

Dimethylethanolamine: A tertiary amino alcohol with one hydroxyl group and substantially different volatility and functionality. It can be relevant to neutralization but supplies a different reactive structure.
Promoted MDEA Blends: These retain MDEA as a major component while introducing other functional ingredients. Their composition and performance specifications should be compared as complete solvents.
Other Chemical or Physical Gas-Treatment Solvents: These may be more appropriate for particular gas compositions and pressure regimes. Selection requires an assessment of the entire separation duty rather than a single chemical-property comparison.

QUALITY CONTROL AND PURCHASING CRITERIA

Specify whether the purchase concerns concentrated MDEA, an aqueous solution or an activated blend. State concentration on an unambiguous basis and identify any promoter or other component that is part of the required product.
Core quality measures can include MDEA assay, water, color and the relevant amine impurity profile. Secondary-amine impurities, metals, ionic contamination or nonvolatile residues may require additional limits according to the intended application.
For a gas-treatment purchase, distinguish fresh-solvent quality from the analytical program used for the circulating solution. For polymer chemistry, water and functional-group calculations may be central; for electronic processing, trace-contamination specifications can be decisive.
The TDS explains the technical characteristics of MDEA Methyldiethanolamine, the SDS addresses hazards and handling, and a batch COA reports release results for the actual lot. A representative assay of 99% does not establish food, pharmaceutical or electronic grade without the relevant specification and supporting documentation.
Discuss packaging compatibility, quantity, traceability and the required declarations with Ataman Kimya. Confirm all supply-specific information for the material being offered rather than relying on a generic MDEA description.

STARTING FORMULATION APPROACHES FOR MDEA METHYLDIETHANOLAMINE

The following examples illustrate how MDEA Methyldiethanolamine can be evaluated during formulation and process development. They are preliminary laboratory screening approaches, not validated commercial recipes, production instructions or finished formulations with established regulatory compliance.

MDEA Methyldiethanolamine, also known as N-methyldiethanolamine or MDEOA, is a tertiary alkanolamine with two hydroxyl groups. Its basic nitrogen supports acid neutralization, while its water compatibility enables aqueous formulation studies. MDEA has one acid-neutralizing amine site per molecule; its two hydroxyl groups must not be counted as additional base equivalents.

The proposed quantities are illustrative starting levels. Unless otherwise specified, percentages are by mass of the final mixture and MDEA quantities refer to active methyldiethanolamine. Correct the weighed amount for the supplied product's assay and water content, and adjust formulation water accordingly. Raw-material quality, equipment, application conditions and the complete formulation must be verified through laboratory trials, performance testing, workplace safety assessment and relevant regulatory checks.

EXAMPLE 1: MDEA METHYLDIETHANOLAMINE CONCENTRATION SCREENING IN AN AQUEOUS GAS-TREATING SOLVENT

Objective: Compare how MDEA concentration affects solution viscosity, carbon dioxide absorption rate and measured gas loading in a controlled laboratory study.

Starting components:

MDEA Methyldiethanolamine: approximately 30%, 40% and 50%

Demineralized water: respectively 70%, 60% and 50%, adjusted for any water in the MDEA feed

Activators, corrosion inhibitors and antifoams: omitted during the initial comparison

Test temperature: approximately 40 °C, held constant

Initial liquid mass, gas composition, gas flow, contact geometry and agitation: held constant

Use a defined carbon dioxide/nitrogen test mixture and a water blank for the first comparison. This CO2 screening does not establish hydrogen sulfide selectivity, industrial treating performance or regeneration energy requirements. Unactivated MDEA and activated commercial solvents require separate evaluation.

Application approach:

Charge most of the demineralized water into a suitable vessel. Add MDEA Methyldiethanolamine gradually under stirring while monitoring temperature, then add the remaining water to obtain the target composition. Measure initial amine concentration, viscosity and appearance using defined analytical conditions. Bring the solution to the selected test temperature in an engineered gas-absorption apparatus with controlled gas delivery and a safe exhaust. Expose each solution to the same test gas under identical contact conditions. Record inlet and outlet carbon dioxide concentrations over time and calculate uptake using a gas balance that accounts for gas flow and water vapor. Determine liquid carbon dioxide loading by a validated analytical method and report it per unit mass of solution and per mole of MDEA. Compare absorption rate, loading and viscosity, and repeat the most promising concentration to check reproducibility.

Do not interpret a short absorption test as an equilibrium-capacity measurement. Changes in viscosity, gas-liquid mass transfer and residence time can influence the apparent MDEA performance.

Use splash goggles, suitable chemical-resistant gloves and effective ventilation when handling methyldiethanolamine. Gas-cylinder controls and exhaust arrangements must address pressure and asphyxiation hazards. Hydrogen sulfide testing requires a dedicated engineered facility and is outside this initial screening approach.

EXAMPLE 2: MDEA METHYLDIETHANOLAMINE NEUTRALIZATION SCREENING IN A WATER-REDUCIBLE ACRYLIC RESIN

Objective: Determine how the degree of MDEA neutralization affects resin dilution behavior, pH stability, viscosity and the properties of the resulting coating.

Starting components:

Acid-functional acrylic resin designed for amine neutralization: 100 parts by mass on a dry-resin basis

Illustrative resin acid value: 50 mg KOH/g dry resin

MDEA Methyldiethanolamine: approximately 6.37, 8.50 and 10.62 parts per 100 parts of dry resin

Corresponding theoretical neutralization levels: respectively 60%, 80% and 100%

Demineralized water: adjusted to the same final dry-resin concentration; any resin-compatible co-solvent: held constant using the recommended base vehicle

Pigments, rheology modifiers and other additives: omitted during the initial comparison

Mixing temperature, addition rate, dilution sequence, film thickness and drying conditions: held constant within the resin supplier's recommendations

For this calculation, MDEA molecular weight is taken as 119.16 g/mol and one mole of MDEA neutralizes one equivalent of carboxylic acid. Active MDEA mass = dry resin mass × acid value × 119.16 / 56100 × neutralization fraction. Use the actual resin acid value and MDEA assay; the calculated neutralization percentage is not a guaranteed final pH.

Application approach:

Verify the resin's solids content, acid value and compatibility with tertiary amine neutralization. Weigh equal quantities of dry-resin equivalent for each trial.
Prepare each MDEA addition using a fixed portion of the formulation water where compatible with the resin system. At the resin supplier's recommended neutralization stage, add MDEA gradually under controlled mixing and monitor temperature. Complete dilution according to the resin's required sequence while keeping final resin concentration comparable between trials. Measure pH, viscosity, clarity or dispersion uniformity after a defined equilibration period and again after 24 hours.
Apply matched films, dry under identical conditions, and compare adhesion, appearance, drying behavior and water resistance. Recheck pH and viscosity after 7 days, then identify the MDEA level giving the best balance of storage stability and coating performance.

If the resin requires a minimum neutralization level to remain dispersible, screen only within that compatible range. Avoid selecting methyldiethanolamine dosage solely from the highest initial pH or the lowest initial viscosity.

Neutralization can generate heat. Add MDEA under temperature control, prevent splashing and review the hazards of any co-solvent. Use eye protection, suitable gloves and ventilation appropriate to the complete resin system.

EXAMPLE 3: MDEA METHYLDIETHANOLAMINE LEVEL SCREENING IN AN AQUEOUS METALWORKING-FLUID BASE

Objective: Investigate how MDEA dosage affects carboxylic-acid neutralization, pH reserve, solution stability and ferrous-metal corrosion behavior in a simplified aqueous fluid base.

Starting components:

MDEA Methyldiethanolamine: approximately 0.30%, 0.50% and 0.80%

Sebacic acid: approximately 0.20%, held constant

Compatible low-foam nonionic wetting agent: approximately 0.10%, held constant

Demineralized water: respectively 99.40%, 99.20% and 98.90%, adjusted for raw-material water content

Mineral oil, additional amines, biocides and other performance additives: omitted during the initial comparison

Mixing conditions, test-metal preparation, exposure period and temperature: held constant

These mixtures are model screening fluids, not complete cutting-fluid formulations or concentrates. MDEA neutralization of a corrosion-inhibiting acid must be assessed as part of a balanced formulation; methyldiethanolamine alone does not establish corrosion protection, lubricity or microbial control.

Application approach:

Charge most of the water into a clean vessel and introduce the sebacic acid under agitation. Add MDEA Methyldiethanolamine slowly while monitoring temperature and the progress of dissolution and neutralization. Add the low-foam wetting agent, then complete the mixture with water to the target mass. Confirm uniformity and measure pH and reserve alkalinity using a defined titration method after equilibration. Compare corrosion behavior using identically prepared steel coupons or a defined cast-iron chip test. Assess foam formation, foam decay and any precipitation or haze. Repeat selected tests with water of a defined hardness, keeping the MDEA and acid levels comparable.
Measure pH and appearance after 7 days and compare the effect of MDEA concentration on stability and corrosion results.

Evaluate aluminum and copper alloys separately before claiming compatibility with non-ferrous metals. Any later addition of lubricants, corrosion inhibitors or preservation agents requires renewed compatibility and performance testing.
Avoid nitrite and other nitrosating agents, and review secondary-amine impurities in the supplied MDEA grade. Do not infer antimicrobial efficacy from alkalinity. Control mist exposure, use eye and hand protection, and manage test-fluid waste according to its full composition and applicable requirements.

REGULATED APPLICATIONS AND COMMERCIAL DISTINCTIONS

MDEA is listed in Schedule 3, Part B, item 16 of the Chemical Weapons Convention. Applicable national reporting and transfer requirements should be checked for the particular industrial transaction; this listing is separate from dangerous-goods transport classification.
The chemical name and CAS number do not establish suitability for food, pharmaceutical, cosmetic or medical applications. A synthesis intermediate and an ingredient intended for direct exposure require different qualifications.
Likewise, low volatility does not establish universal VOC exemption, and a general technical grade does not establish electronic-grade cleanliness. Use the definitions, specifications and declarations applicable to the actual market and application.
No current stock, origin, certification, exclusive distribution status or guaranteed process performance is asserted here. Those details require confirmation for the proposed supply.

FIRST AID

Inhalation: Move a person exposed to MDEA Methyldiethanolamine vapor or mist to fresh air and obtain medical advice if symptoms occur or persist. Breathing difficulty requires urgent attention; rescuers must avoid exposure to any associated process gas.
Skin Contact: Remove clothing contaminated with MDEA Methyldiethanolamine and wash the skin promptly with plenty of water. Obtain medical advice if irritation or other symptoms develop, and clean contaminated clothing before reuse.
Eye Contact: Immediately rinse MDEA Methyldiethanolamine from the eyes with plenty of running water for at least 15 minutes, including under the eyelids. Remove contact lenses if easily possible and obtain medical attention because MDEA can cause serious eye irritation.
Ingestion: Rinse the mouth after accidental ingestion of MDEA and obtain medical advice promptly. Do not induce vomiting or give anything by mouth to an unconscious person.
Hot Liquid Contact: Cool a burn from hot MDEA with cool running water while arranging medical assistance. Consider both the thermal injury and chemical exposure, and do not apply improvised neutralizing chemicals.
Note to Physicians: Provide the actual MDEA Methyldiethanolamine SDS and identify whether the material was fresh amine, a promoted blend or a loaded process solution. Treat according to symptoms and all relevant exposure components.

HANDLING AND STORAGE

Handling: Transfer MDEA Methyldiethanolamine with procedures that prevent splashing, skin contamination and mist generation. Keep containers closed when not in use and minimize unnecessary contact with atmospheric moisture.

Engineering Controls: Provide suitable ventilation for MDEA Methyldiethanolamine handling, particularly during heated processing, spraying or maintenance. Make eyewash and emergency washing facilities readily accessible.

Personal Protection: Wear chemical splash goggles, suitable gloves and protective clothing when handling MDEA. Select glove material and replacement intervals from the current SDS, glove data and actual contact conditions.

Respiratory Protection: Where MDEA exposure cannot be adequately controlled, select respiratory protection through the workplace assessment. Protection suitable for amine vapor or aerosol is not automatically suitable for H2S, oxygen deficiency or an unknown process atmosphere.
Storage: Keep MDEA Methyldiethanolamine tightly closed in a cool, dry, well-ventilated location, away from excessive heat and incompatible materials. Follow the supplied grade's storage-temperature and shelf-life instructions.

Material Compatibility: Confirm tanks, seals, transfer lines and packaging for the MDEA grade and its service conditions. Do not assume that compatibility with fresh amine establishes compatibility with a hot, acid-gas-loaded or contaminated solution.

Chemical Incompatibilities: Prevent uncontrolled MDEA contact with strong oxidizing agents, strong acids and reactive chemicals identified in the SDS. Keep nitrites and other nitrosating contamination out of unvalidated amine formulations.

Reactive Processing: MDEA can react with isocyanates through its hydroxyl groups and neutralize acids through its basic center. These are intended reactions only in a properly designed process; uncontrolled mixing or contamination must be prevented.

Fire Precautions: Methyldiethanolamine is an organic liquid that can burn under suitable conditions despite its relatively high flash point. Control ignition sources around heated material and assess the complete blend rather than the neat amine alone.

Spill Procedures: Contain spilled MDEA Methyldiethanolamine and collect it with compatible inert absorbent or suitable recovery equipment. Prevent entry to drains and avoid spreading the water-miscible liquid with uncontrolled wash water.

Loaded Solvent Precautions: MDEA solution from gas-treatment service may release H2S or CO2 and may contain additional contaminants. Use the process-specific isolation, gas monitoring and confined-space arrangements rather than relying only on a fresh-MDEA SDS.

Environmental Precautions: Prevent MDEA Methyldiethanolamine and contaminated runoff from entering soil, drains or waterways. Water miscibility can spread a release and does not establish that discharge is acceptable.

Fire Response: Follow the MDEA SDS and site emergency plan, using suitable extinguishing media such as water spray, carbon dioxide, dry chemical or alcohol-resistant foam as appropriate. Firefighters need suitable breathing apparatus and protection from combustion gases, which can include carbon oxides and 
nitrogen oxides.

Waste Disposal: Send waste MDEA, spent solvent, absorbents and contaminated packaging through an authorized route appropriate to their full composition. Do not assign the waste classification of a used gas-treatment solution from the fresh chemical's transport status.

SAFETY AND TRANSPORT INFORMATION

Serious eye irritation is identified in the reviewed MDEA safety information. Some jurisdictions also classify oral acute toxicity differently; for example, a published Canadian substance assessment identifies Acute Toxicity, Oral, Category 4 and Eye Irritation, Category 2A, while the reviewed September 2025 supplier SDS lists eye irritation as its classification.
The current regional SDS for the exact supplied MDEA Methyldiethanolamine grade therefore remains the reference for labeling and workplace precautions. No universal classification should be inferred from one regional document, and a promoted or loaded solution requires consideration of all its components.
The reviewed concentrated-MDEA SDS describes road/rail, sea and air transport as not regulated as dangerous goods.
UN Number: Not assigned under the reviewed non-dangerous-goods classification; confirm the actual grade and shipment.
Proper Shipping Name: Not applicable under that classification.
Transport Hazard Class: Not assigned under that classification.
Packing Group: Not assigned under that classification.
This transport status does not remove chemical handling precautions, national trade controls or the process-gas hazards associated with spent or loaded MDEA solvent.

FREQUENTLY ASKED QUESTIONS ABOUT MDEA METHYLDIETHANOLAMINE

What is MDEA Methyldiethanolamine?
MDEA Methyldiethanolamine is N-methyldiethanolamine, a tertiary alkanolamine with two hydroxyl groups and CAS Number 105-59-9.

What is the EC number and molecular formula of MDEA Methyldiethanolamine?
The EC number of MDEA Methyldiethanolamine is 203-312-7 and the formula is C5H13NO2.

What is the molecular weight of MDEA Methyldiethanolamine?
Approximately 119.16 g/mol.

Why is MDEA described as a tertiary amine?
The nitrogen of MDEA Methyldiethanolamine is bonded to one methyl group and two hydroxyethyl groups, with no nitrogen-bound hydrogen in the neutral molecule.

Is MDEA miscible with water?
Yes; concentrated MDEA is completely miscible with water.

What are the boiling and freezing points of MDEA Methyldiethanolamine?
Representative concentrated-material values are 243–248 °C at 760 mmHg and approximately −21 °C, respectively.

What is the viscosity of MDEA Methyldiethanolamine?
A representative dynamic viscosity is 101 mPa·s at 20 °C; aqueous solutions and promoted blends have different values.

Why can MDEA remove H2S selectively?
H2S reacts rapidly through acid–base chemistry, while unpromoted CO2 absorption is slower under relevant aqueous treatment conditions.

Does MDEA also absorb CO2?
Yes; aqueous MDEA supports bicarbonate-based CO2 absorption, and promoted systems can be designed for CO2-removal duties.

What is activated MDEA?
It is an MDEA-containing solvent with additional functional components, such as a promoter; the name does not define one standard formulation.

Can pure MDEA data describe an activated blend?
No; the full solvent composition, temperature and acid-gas loading must be considered.

Is MDEA a once-through H2S scavenger in its main application?
The principal gas-treatment use of MDEA Methyldiethanolamine is in regenerative solvent systems, where absorbed acid gas is released and the solvent recirculates.

Can MDEA Methyldiethanolamine be used in metalworking fluids?
Yes; documented functions include pH buffering and an anticorrosion contribution in suitable formulations.

Can MDEA Methyldiethanolamine neutralize coating resins?
Yes; MDEA Methyldiethanolamine can neutralize suitable acidic resin groups, with the required level determined by the resin and formulation.

Is MDEA a stand-alone photoinitiator?
The documented role of MDEA Methyldiethanolamine is as an amine co-initiator in selected Type II systems, not as a universal stand-alone photoinitiator.

How does MDEA Methyldiethanolamine participate in polyurethane chemistry?
The two hydroxyl groups of MDEA Methyldiethanolamine can react with isocyanates in a designed synthesis, while its tertiary nitrogen has no N–H curing functionality.

Does reaction with a fatty acid automatically make a quaternary ammonium compound?
No; simple acid neutralization forms a protonated amine salt, while covalent quaternization is a separate chemical transformation.

Is industrial MDEA automatically electronic grade?
No; electronic applications require separately qualified contamination and purity specifications.

What is the main immediate exposure concern with MDEA Methyldiethanolamine?
Eye exposure requires particular care because MDEA can cause serious eye irritation; follow the current regional SDS for all applicable hazards.

Is fresh MDEA transport classification sufficient for used solvent?
No; loaded or contaminated solvent can have additional hazards, including release of absorbed process gases.

Which documents should be requested before purchasing MDEA Methyldiethanolamine?
Obtain the current TDS and regional SDS, the agreed grade specification and batch COA, plus any application-specific declarations.

TECHNICAL SUMMARY

MDEA Methyldiethanolamine is a tertiary amino diol identified by CAS Number 105-59-9, EC Number 203-312-7 and molecular formula C5H13NO2. Its two hydroxyethyl groups and basic nitrogen center support a broad technical scope, but the function used in one industry should not be confused with the function used in another.
The principal gas-treatment distinction is the aqueous reaction behavior of MDEA Methyldiethanolamine. MDEA can rapidly absorb H2S through proton-transfer chemistry while taking up CO2 through a slower bicarbonate-based pathway when unpromoted. Suitable process design can exploit this difference for H2S selectivity, whereas a promoted or formulated MDEA solvent may be selected where the CO2-removal duty requires a different balance of kinetics and capacity.

Performance depends on the complete treatment system. Contacting, gas composition, solvent loading, regeneration and contamination determine whether the treated gas meets its specification and whether the process uses energy effectively. Low volatility and a favorable reaction-energy profile are useful selection characteristics, but neither establishes a guaranteed circulation rate, outlet concentration or regeneration saving.
Outside gas treatment, documented applications of MDEA Methyldiethanolamine include metalworking-fluid buffering, neutralization of suitable coating and ink resins, Type II photoinitiator combinations and selected polyurethane or epoxy technologies. The hydroxyl groups provide conventional diol reactivity, while the tertiary amine supplies basic or catalytic behavior; the molecule has no N–H group for a conventional primary-amine curing reaction. Textile-treatment derivatives and high-purity electronic formulations require their own product specifications.

Representative data for concentrated MDEA Methyldiethanolamine include molecular weight 119.16 g/mol, freezing point near −21 °C and dynamic viscosity around 101 mPa·s at 20 °C. Water content, assay and the presence of promoters must remain attached to the measurement, because a circulating aqueous solvent is physically and chemically different from neat MDEA. Theoretical amine and hydroxyl equivalent values can support formulation calculations but do not replace actual batch analysis.
Quality selection should therefore begin with the intended form and function: concentrated amine, aqueous solution, promoted gas-treatment solvent or separately qualified specialty grade. Obtain the appropriate TDS, current regional SDS and batch COA, with additional impurity limits where the application requires them. Control eye and skin exposure, prevent incompatible contamination and assess loaded process solvent for its absorbed gases; non-dangerous-goods transport status for fresh MDEA does not resolve those workplace or trade requirements.

CONTACT ATAMAN KIMYA

Contact Ataman Kimya to discuss MDEA Methyldiethanolamine for gas treatment, coatings, metalworking, polymer chemistry or another documented industrial application. Concentration, suitable grade, water and impurity limits, technical documentation, packaging options and required quantities can be reviewed for the intended use.
Customers may also request information on current availability and a quotation. Any application-specific qualification or supply commitment should be confirmed for the exact MDEA Methyldiethanolamine grade being offered.
Ataman Chemicals
Phone: +90 216 577 10 10
Email: info@atamankimya.com