N- methylmorpholine is a commonly used chemical raw material in the chemical industry. Here, the manufacturer of N- methylmorpholine introduces three pure preparation methods of methylmorpholine for everyone. Let's have a look!

Method 1: Add a certain amount of morpholine and dimethyl carbonate into a four-neck bottle with thermometer, reflux condenser and electric stirrer, and heat to a certain temperature for reaction. After reacting for a certain time. The reflux condenser is replaced by a distillation device to distill the reaction product methanol, and the reaction is stopped when the reaction no longer produces liquid. The yield of the product was measured by GC-MS.. The dimethyl carbonate is extracted from the distilled mixture by an extraction method for recycling.

Method 2: put a certain amount of morpholine and dimethyl carbonate (n (c4h9no) n (c ∶ 3h6o3) = 1: 1.2) into a four-necked bottle with thermometer, reflux condenser and electric stirrer, and heat to a certain temperature (100)℃ for reaction. When the reaction reaches a certain time (3h), the reflux condenser is replaced by a distillation device to distill the reaction product methanol until the reaction stops distilling off the liquid. The yield of N- methylmorpholine was determined by TLC, and the purity of N- methylmorpholine was determined by HPLC.

Method 3: add 87g morpholine into a 250mL three-necked bottle with reflux condenser and electric stirrer, and when heated to 100℃, add a mixture of 57.7g sodium dihydrogen phosphate and 36g paraformaldehyde while stirring. When the temperature reaches 115℃, reflux occurs, keep the temperature for reaction for 20min, then cool, and sodium hydrogen phosphate crystallizes out in the form of water and substance, and filter to separate out the solid to obtain filtrate as a product without drying.