Methyldiethanolamine is a chemical substance that is miscible with water and alcohol and slightly soluble in ether. Widely used in oil field gas and coal gas desulfurization purification emulsifier and acid gas absorbent, acid-base control agent, polyurethane foam catalyst.
1. Obtained by the reaction of formaldehyde and diethanolamine. Add formic acid into the reaction pot and heat to boiling, then add the mixture of formaldehyde and diethanolamine dropwise under stirring, and drop it for about 1 hour, keep the temperature at 90-98°C, and continue to reflux for 4 hours. Then carry out vacuum distillation, collect 120-130 ℃ (0.53kPa) distillate, obtain N-methyldiethanolamine, the yield is 85%. 2. It is derived from the reaction of methylamine and ethylene oxide. Keep the temperature below 30°C, pass ethylene oxide gas into 20% methylamine solution for addition reaction until the relative density of the reaction solution reaches 1.025. Stir for 15 minutes, and the relative density remains unchanged, which is the end point. Recover methylamine at normal pressure to 103°C, and distill water under reduced pressure to collect fractions at 119-170°C (4.67kPa). That is the finished product. Yield 72%. Raw material consumption quota: ethylene oxide 950kg/t, methylamine (40%) 870kg/t. In addition, N-methyldiethanolamine can also be prepared by catalytic hydrogenation with formaldehyde and cyanoethanol as raw materials.
