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Methyldiethanolamine, also known as N-methyl diethanolamine and more commonly as MDEA, is the organic compound with the formula CH3N(C2H4OH)2.
Methyldiethanolamine is a colorless liquid with an ammonia odor.
Methyldiethanolamine is miscible with water, ethanol and benzene.
CAS: 105-59-9
MF: C5H13NO2
MW: 119.16
EINECS: 203-312-7
Synonyms
N,N-BIS(2-HYDROXYETHYL)METHYLAMINE;N-METHYL-2,2'-IMINODIETHANOL;N-METHYL-2,2-IMINOBIS(ETHANOL);N-METHYLDIETHANOLAMINE;N-METHYL-N-(2-HYDROXYETHYL)-2-AMINOETHANOL;METHYL DIETHANOLAMINE;MDEA;BIS(2-HYDROXYETHYL)METHYLAMINE;N-METHYLDIETHANOLAMINE;105-59-9;Bis(hydroxyethyl)methylamine;Methyldiethanolamine;Methyl diethanolamine;Ethanol, 2,2'-(methylimino)bis-;2,2'-(Methylimino)diethanol;591248-66-7;N-Methylaminodiglycol;N-Methyldiethanolimine;N-Methyliminodiethanol;2,2'-Methyliminodiethanol;N-Methyl-2,2'-iminodiethanol;2-[2-hydroxyethyl(methyl)amino]ethanol;USAF DO-52;N-methyl diethanolamine;N,N-Bis(2-hydroxyethyl)methylamine;Bis(2-hydroxyethyl)methylamine;Methylbis(2-hydroxyethyl)amine;Diethanolmethylamine;Methyliminodiethanol;Bis(2-hydroxyethyl) methyl amine;Ethanol, 2,2'-(methylimino)di-;NSC 11690;CCRIS 4843;N,N-Di(2-hydroxyethyl)-N-methylamine;2-(N-2-Hydroxyethyl-N-methylamino)ethanol;EINECS 203-312-7;UNII-3IG3K131QJ;BRN 1734441;N-Methylimino-2,2'-diethanol;DTXSID8025591;HSDB 6804;n-methyl-diethanol amine;AMINO ALCOHOL MDA;NSC-11690;N-Methyl-2,2-iminodiethanol;3IG3K131QJ;DTXCID605591;METHYLDIETHANOLAMINE, N-;2-[(2-hydroxyethyl)(methyl)amino]ethan-1-ol;EC 203-312-7;4-04-00-01517 (Beilstein Handbook Reference);N-METHYLDIETHANOLAMINE [HSDB];N-(2-Hydroxyethyl)-N-methylethanolam;n-methyl-n,n-bis(2-hydroxyethyl)amine;2,2'-(METHYLIMINO)BIS(ETHANOL);Ethanol,2'-(methylimino)di-;Ethanol,2'-(methylimino)bis-;WLN: Q2N1 & 2Q;N-methyl-diethanolamine;bis-(Hydroxyethyl)methylamine;methyldiethanolamin;MDEA amine;Mdea (diol);NMethylaminodiglycol;Amietol M12;N-Methyldethanolamne;n-methyldiethanolamin;NMethyldiethanolimine;NMethyliminodiethanol;methyl diethanol amine;N-methyl diethanol-amine;2,2'Methyliminodiethanol;di(hydroxyethyl)methylamine;NMethyl2,2'iminodiethanol;2,2'(Methylimino)diethanol;2-Hydroxy-1-[(2-hydroxyethyl)methylamino]-ethyl;SCHEMBL17605;2,2`(Methylimino)bisethanol;Bis(2hydroxyethyl)methylamine;Methylbis(2hydroxyethyl)amine;N-Methyldiethanolamine, 99%;NMethylbis(2hydroxyethyl)amine;Ethanol, 2,2'(methylimino)di;Bis(2hydroxyethyl) methyl amine;2,2`-(Methylimino)bis-ethanol;CHEMBL3185149;Ethanol, 2,2'(methylimino)bis;N-Methyldiethanolamine, >=99%;2,2'-(methylazanediyl)diethanol;N,NBis(2hydroxyethyl)methylamine;N,NDi(2hydroxyethyl)Nmethylamine;N(2hydroxyethyl)Nmethylethanolamine;NSC11690;NSC49131;NSC51500;2(N2HydroxyethylNmethylamino)ethanol;METHYL DIETHANOLAMINE [INCI];Tox21_201199;MFCD00002848;NSC-49131;NSC-51500;STL281951;2,2'-METHYLIMINODIETHANOLAMINE;AKOS009031354;N,N-bis-(2-hydroxyethyl)-methylamine;AT34020;N-METHYLBIS(2-HYDROXYETHYL)AMINE;NCGC00248955-01;NCGC00258751-01;CAS-105-59-9;LS-13102;2-[(2-hydroxy-ethyl)methyl-amino]-ethanol;DB-297071;M0505;NS00004394;N-(2-HYDROXYETHYL)-N-METHYLETHANOLAMINE;2,2'-(METHYLAZANEDIYL)BIS(ETHAN-1-OL);ethane, 1-hydroxy-2-(2-hydroxyethylmethyl)amino-;Q252344,J-523676;ethane, 1-hydroxy-2-(2-hydroxyethyl-N-methyl)amino-;N-Methyldiethanolamine 1000 microg/mL in Ammonium Hydroxide
A tertiary amine, Methyldiethanolamine is widely used as a sweetening agent in chemical, oil refinery, syngas production and natural gas.
Similar compounds are Methyldiethanolamine, a primary amine, and diethanolamine (DEA), a secondary amine, both of which are also used for amine gas treating.
Methyldiethanolamine's defining characteristic when compared to these other amines is its ability to preferentially remove H2S (and strip CO2) from sour gas streams.
Methyldiethanolamine's popularity as a solvent for gas treating stems from several advantages it has when compared to other alkanolamines.
One of these advantages is a low vapor pressure, which allows for high amine compositions without appreciable losses through the absorber and regenerator.
Methyldiethanolamine is also resistant to thermal and chemical degradation and is largely immiscible with hydrocarbons.
Methyldiethanolamine is a common base note in perfumes to allow the fragrance to last.
Lastly, Methyldiethanolamine has a relatively low heat of reaction with hydrogen sulfide and carbon dioxide, which allows for lower reboiler duties, thus lower operating costs.
Methyldiethanolamine is less reactive towards CO2, but has an equilibrium loading capacity approaching 1 mole CO2 per mole amine.
Methyldiethanolamine also requires less energy to regenerate.
To combine the advantages of Methyldiethanolamine and the smaller amines, Methyldiethanolamine is usually mixed with a catalytic promoter such as piperazine, PZ, or a fast reacting amine such as MEA to retain reactivity, but lower regeneration costs.
Activated Methyldiethanolamine or aMDEA uses piperazine as a catalyst to increase the speed of the reaction with CO2.
Methyldiethanolamine has been commercially successful.
Many tests have been done on the performance of MDEA/MEA or MDEA/piperazine mixtures compared to single amines.
CO2 production rates were higher than Methyldiethanolamine for the same heat duty and total molar concentration when experiments were performed in the University of Regina pilot plant, which is a modeled after a natural gas plant.
There were also insignificant trace amounts of degradation products detected.
However, when the same control variables and tests were conducted at the Boundary Dam Power Station plant, the CO2 production rate for the mixed solvent was lower than MEA.
This was a result of the reduction in the capacity of the solvent to absorb CO2 after degradation.
Because the Boundary Dam plant is a coal-fired power plant, Methyldiethanolamine operates under harsher environments and produces an impure flue gas containing, fly ash, SO2, and NO2 that are fed into carbon capture.
Even with flue gas pretreatment, there is still enough to produce degradation products such as straight chain amines and sulfur compounds, which accumulate so Methyldiethanolamine is no longer possible to regenerate MEA and MDEA.
For these blends to be successful in reducing heat duty, their chemical stabilities must be maintained.
Methyldiethanolamine Chemical Properties
Melting point: -21 °C
Boiling point: 246-248 °C(lit.)
Density: 1.038 g/mL at 25 °C(lit.)
Vapor density: 4 (vs air)
Vapor pressure: 0.01 mm Hg ( 20 °C)
Refractive index: n20/D 1.469(lit.)
Fp: 260 °F
Storage temp.: Store below +30°C.
Solubility: Chloroform (Slightly), Methanol (Slightly)
Form: Liquid
pka: 14.41±0.10(Predicted)
Color: Clear colorless to light yellow
Odor: Ammonical
PH Range: 11.5 at 100 g/l at 20 °C
PH: 11.5 (100g/l, H2O, 20℃)
Explosive limit: 0.9-8.4%(V)
Water Solubility: MISCIBLE
BRN: 1734441
Stability: Stable. Combustible. Incompatible with strong oxidizing agents.
InChIKey: CRVGTESFCCXCTH-UHFFFAOYSA-N
LogP: -1.16 at 23℃
CAS DataBase Reference: 105-59-9(CAS DataBase Reference)
NIST Chemistry Reference: Methyldiethanolamine (105-59-9)
EPA Substance Registry System: Methyldiethanolamine (105-59-9)
Methyldiethanolamine is a colorless to yellow viscous liquid with an ammonia-like odor.
Methyldiethanolamine is completely soluble in water.
Methyldiethanolamine is an alkyl alkanolamine.
Methyldiethanolamine combines the chemical characteristics of both amines and alcohols so that it is capable of undergoing reactions typical of both alcohols and amines: forming quaternary amine salts, soaps, and esters.
Uses
Methyldiethanolamine is a reagent used for protection of boronic acids as N-methyl-O,O-diethanolamine esters.
Methyldiethanolamine is used as an intermediate in the synthesis of numerous products.
Methyldiethanolamine's unique chemistry has resulted in its use in diverse areas, including coatings, textile lubricants, polishes, detergents, pesticides, personal-care products, pharmaceuticals, urethane catalysts, and water-treatment chemicals.
Methyldiethanolamine is also used in absorption of acidic gases, catalyst for polyurethane foams, pH control agent.
Methyldiethanolamine is a new solvent with excellent performance for selective desulfurization and decarburization.
Methyldiethanolamine has the advantages of high selectivity, less solvent consumption, remarkable energy saving effect, and not easy to degrade.
Widely used in oil gas and gas desulfurization purification emulsifier and acid gas absorbent, acid-base control agent, polyurethane foam catalyst.
The carbon dioxide in synthetic ammonia can be removed with the participation of an activator, so that it has been gradually promoted in the absorption of carbon dioxide in flue gas in recent years.
In addition, Methyldiethanolamine can also be used as pesticides, emulsifiers, semi-finished products of fabric additives, intermediates of antineoplastic drug hydrochloric acid nitrogen mustard, catalyst of carbamate coatings, Methyldiethanolamine is also a drying accelerator for paint.
Reactivity Profile
Methyldiethanolamine is an aminoalcohol.
Amines are chemical bases.
They neutralize acids to form salts plus water.
These acid-base reactions are exothermic.
The amount of heat that is evolved per mole of amine in a neutralization is largely independent of the strength of the amine as a base.
Amines may be incompatible with isocyanates, halogenated organics, peroxides, phenols (acidic), epoxides, anhydrides, and acid halides.
Flammable gaseous hydrogen is generated by amines in combination with strong reducing agents, such as hydrides.
Methyldiethanolamine may react with oxidizing materials.
Production
Methyldiethanolamine is produced by ethoxylation of methylamine using ethylene oxide:
CH3NH2 + 2 C2H4O → CH3N(C2H4OH)2
Another route involves hydroxymethylation of diethanolamine followed by hydrogenolysis.
Production Method
1. From the reaction of formaldehyde and diethanolamine.
Formic acid was added to the reaction pot and heated to boiling, and a mixed solution of formaldehyde and diethanolamine was added dropwise under stirring for about 1H.
The temperature was maintained at 90-98 ° C., and reflux was continued for 4 hours.
Then, distillation under reduced pressure was carried out to collect a fraction at 120-130 ° C. (0.53kPa) to obtain N-methyldiethanolamine in a yield of 85%.
Derived from the reaction of methylamine with ethylene oxide.
The temperature was kept below 30 ° C., and the addition reaction was carried out by introducing ethylene oxide gas into 20% methylamine solution until the relative density of the reaction solution reached 1.025.
Stirring for 15min, the relative density is unchanged for the end point.
Methyldiethanolamine was recovered to 103 ° C.
Under normal pressure, and after water was evaporated under reduced pressure, a 119-170 ° C.
(4.67kPa) fraction was collected.
Methyldiethanolamine is the finished product.
The yield was 72%. Raw material consumption quota: Ethylene oxide 950kg/t, methylamine (40%)870kg/t.
In addition, Methyldiethanolamine can be obtained by catalytic hydrogenation of formaldehyde and cyanoethanol.
