Methylamine Solution in Methanol 33%

Methylamine 33% Solution in Methanol

Other Names: Monomethylamine solution in methanol, Methanamine solution in methanol, Aminomethane solution in methanol
Chemical Formula: CH₃NH₂ in CH₃OH
Molar Mass: 31.06 g/mol (methylamine)
CAS Number: 74-89-5 (methylamine); 67-56-1 (methanol)
Concentration: 33 wt.% methylamine in methanol
SMILES: CN.CO
Appearance: Colorless, volatile liquid solution
Odor: Strong, pungent, ammonia-like to fish-like odor

Methylamine 33% solution in methanol is a concentrated solution of the simplest primary alkylamine in a polar protic solvent. Methylamine consists of a methyl group directly bonded to an amino group and contains a nitrogen lone pair that gives the molecule pronounced basic and nucleophilic properties. Methanol provides a homogeneous reaction medium while also participating in extensive intermolecular hydrogen bonding with methylamine. Experimental and theoretical studies of methylamine–methanol systems demonstrate the formation of hydrogen-bonded molecular complexes involving the amino group of methylamine and the hydroxyl group of methanol. These interactions influence molecular association, solvation and the physicochemical behaviour of the solution.

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Chemical and physical properties

Methylamine is a small, strongly polar primary amine. The nitrogen atom contains a lone electron pair and can act as a hydrogen-bond acceptor, while the N–H groups can participate as hydrogen-bond donors. Methanol similarly acts as both a hydrogen-bond donor and acceptor, resulting in substantial intermolecular association when the two compounds are mixed.

Pressure–volume–temperature investigations of methylamine–methanol systems have demonstrated the formation of distinct hydrogen-bonded complexes. Thermodynamic parameters obtained from these measurements confirm favourable association between methylamine and methanol molecules. Computational studies likewise predict stable mixed methylamine–methanol complexes and show that hydrogen bonding modifies their donor–acceptor and acid–base characteristics.

Molecular-dynamics studies of liquid methylamine and methanol show that both compounds form hydrogen-bonded networks, although their local structures differ. Liquid methanol tends to form predominantly chain-like hydrogen-bonded arrangements, whereas methylamine exhibits more highly branched molecular association because its amino group provides multiple possible hydrogen-bonding sites.

The 33 wt.% solution is highly volatile because both methylamine and methanol possess relatively low boiling temperatures. Its exact density, vapour pressure, boiling range and refractive index depend on concentration, temperature and product specification. Consequently, concentration-specific physical parameters should be determined from analytical measurements or the specification of the individual batch rather than extrapolated directly from pure-component data.

Applications

Methylamine solution in methanol is extensively used as a reagent in synthetic organic chemistry. The nitrogen lone pair makes methylamine an effective nucleophile, allowing it to participate in nucleophilic substitution, acylation, condensation and related carbon–nitrogen bond-forming reactions.

The solution is particularly convenient for introducing methylamino and N-methyl-containing structural units into organic molecules. Using methylamine already dissolved in methanol facilitates accurate handling of the otherwise highly volatile amine and provides a homogeneous polar reaction medium suitable for numerous synthetic transformations.

Methylamine in methanolic solution has been employed in laboratory synthesis for reactions with esters and related carbonyl derivatives, formation of methylamides and preparation of nitrogen-containing organic intermediates. Published synthetic studies demonstrate the use of concentrated methylamine–methanol solutions as practical reagents in preparative organic chemistry.

It is also useful in physical and theoretical chemistry as a model system for studies of hydrogen bonding, solvation, molecular association, proton-transfer behaviour and intermolecular donor–acceptor interactions in mixtures of primary amines and alcohols.

Scientific references

Millen, D. J., Mines, G. W. “Hydrogen bonding in the gas phase. Part 2.—Determination of thermodynamic parameters for amine–methanol systems from pressure, volume, temperature measurements.” Journal of the Chemical Society, Faraday Transactions 2, 1974, 70, 693–699. DOI: 10.1039/F29747000693.

Kosztolányi, T., Bakó, I., Pálinkás, G. “Hydrogen bonding in liquid methanol, methylamine, and methanethiol studied by molecular-dynamics simulations.” The Journal of Chemical Physics, 2003, 118(10), 4546–4555. DOI: 10.1063/1.1543143.

Samuilov, A., Samuilov, Y. “Reactivity of hydrogen-bonded complexes of water, methanol, phenol and methyl amine.” New Journal of Chemistry, 2023. DOI: 10.1039/D3NJ04052F.

Samuilov, A. Ya., Balabanova, F. B., Samuilov, Ya. D., Konovalov, A. I. “Quantum-Chemical Study of Thermodynamics of Hydrogen-Bonded Methylamine–Methanol Complexes Reaction with Dimethyl Carbonate.” Russian Journal of General Chemistry, 2014, 84(8), 1480–1486. DOI: 10.1134/S1070363214080052.

Corbin, D. R., Schwarz, S., Sonnichsen, G. C. “Methylamines synthesis: A review.” Catalysis Today, 1997, 37(2), 71–102. DOI: 10.1016/S0920-5861(97)00003-5.

Safety

Signal Word: Danger

Hazard Statements:
H225: Highly flammable liquid and vapor
H301: Toxic if swallowed
H311: Toxic in contact with skin
H331: Toxic if inhaled
H314: Causes severe skin burns and eye damage
H370: Causes damage to organs (methanol component)

Precautionary Statements:
P210: Keep away from heat, hot surfaces, sparks, open flames – No smoking
P260: Do not breathe vapors
P280: Wear protective gloves, clothing, and eye/face protection
P301+P310: IF SWALLOWED: Immediately call a POISON CENTER or doctor
P303+P361+P353: IF ON SKIN: Remove contaminated clothing immediately. Rinse skin with water
P305+P351+P338: IF IN EYES: Rinse cautiously with water. Remove contact lenses if present and easy to do
P501: Dispose of contents/container in accordance with regulations

First Aid Measures
Eye Contact: Rinse with water for at least 15 minutes. Seek immediate medical attention
Skin Contact: Wash with plenty of water and soap. Remove contaminated clothing
Inhalation: Move to fresh air, administer oxygen if needed, seek emergency help
Ingestion: Do not induce vomiting. Rinse mouth. Get medical help immediately

Handling and Storage
Store in tightly sealed containers in a cool, well-ventilated flammable-liquids cabinet
Keep away from ignition sources, heat, and oxidizing agents
Use explosion-proof equipment and grounding/bonding measures during transfer
Ensure handling in fume hoods or well-ventilated areas

IMPORTANT NOTICE:

ONLY COMPANY ORDERS ACCEPTED.
This product is intended exclusively for industrial and laboratory use by verified business customers.