Methylal purifying method

[0016] Add 10kg of water to 100kg of methylal with a mass concentration of 91% and fully stir it. After standing still for 20 minutes, separate layers to obtain 63.5kg of the upper layer solution. Add 2.0kg of anhydrous magnesium sulfate (2.0kg of anhydrous The water absorption of magnesium sulfate is 2.0kg, and the water content of the upper layer of 63.5kg is about 1.9kg), and stirred for 5 minutes, after drying, the desiccant is filtered out to obtain 60.1kg of methylal with a mass concentration of 99.6%, and the obtained lower layer solution is methylal , a mixture of methanol and water, methylal and methanol can be recovered through rectification; hydrous magnesium sulfate can be recovered and reused after dehydration.

[0018] Add 30kg of water to 200kg of methylal with a mass concentration of 86% and stir well, stand still for 30 minutes, and separate layers to obtain 85.6kg of the upper layer solution. Add 10kg of anhydrous calcium chloride (10kg of anhydrous chloride Calcium water absorption is 9.7kg, 85.6kg upper layer solution has a water content of about 2.6kg), and stirred for 10 minutes, dried and filtered out the desiccant to obtain 81.1kg of methylal with a mass concentration of 99.7%, and the obtained lower layer solution is methylal The mixture of , methanol and water can be used for the synthesis of methylal; the calcium chloride in water can be reused after dehydration.

[0020] Add 150g of water to 500g of methylal with a mass concentration of 86% and stir well, let stand for 35 minutes, use a separatory funnel to separate layers, and obtain 393g of the upper layer solution, add 10g of molecular sieves to the upper layer solution, and stir for 5 minutes with a glass cup , Filter out the desiccant to obtain 381g of methylal with a mass concentration of 99.5%, and 257g of the resulting lower layer solution is a mixture of methylal, methanol and water; the water-containing molecular sieves are recycled after dehydration.