N-Metilformamid Sentezi?
- Thread starter CryoThio
- Start date
It can be very easily prepared (with proper equipment) from aqueous 40% methylamine and ethyl formate, that is also easily (but need some practice in reactive distillations) accessible from 85% formic acid and 95% ethanol.
The solution was left to cool for a couple of hours and then slowly distilled at atmospheric pressure until most of the alcohol and excess methylamine had distilled off. At about 100° distillation practically ceased. The residue was transferred to a smaller flask and distilled under vacuum at about 70mm Hg. A middle fraction passed over between 40°C (essentially water) to 100°C. The N-methylformamide was collected between 100 and 106°C. It is a colourless, almost odourless, slightly oily liquid. The yield was 25.59g or about 43% of theory.
Discussion
Considerable product was probably lost to the middlings fraction but this fraction was too small to redistill. The use of a vacuum fractional distillation set-up and the use of a larger scale may significantly improve yield and reduce water content. The latter is important if the material is to be used to prepare a Valsmeier-Haack reagent. A much smaller excess of methylamine may be adequate and this would greatly improve the yield relative to methylamine which is probably the limiting material for most amateurs.
N-Methylformamide
60ml of 40% methylamine (c 0.9 moles) solution were added to 50ml (0.62 moles) of vigorously stirred ethyl formate quickly. The mixture became homogeneous almost immediately and an exothermic reaction caused the temperature to rise to about 45°C. When the exothermic reaction subsided the flask was placed on a hotplate set at 100° for 30 minutes to complete the reaction. The reaction mixture did not boil in this time.The solution was left to cool for a couple of hours and then slowly distilled at atmospheric pressure until most of the alcohol and excess methylamine had distilled off. At about 100° distillation practically ceased. The residue was transferred to a smaller flask and distilled under vacuum at about 70mm Hg. A middle fraction passed over between 40°C (essentially water) to 100°C. The N-methylformamide was collected between 100 and 106°C. It is a colourless, almost odourless, slightly oily liquid. The yield was 25.59g or about 43% of theory.
Discussion
Considerable product was probably lost to the middlings fraction but this fraction was too small to redistill. The use of a vacuum fractional distillation set-up and the use of a larger scale may significantly improve yield and reduce water content. The latter is important if the material is to be used to prepare a Valsmeier-Haack reagent. A much smaller excess of methylamine may be adequate and this would greatly improve the yield relative to methylamine which is probably the limiting material for most amateurs.