Method for purifying methylal

A purification method and methylal technology are applied in chemical instruments and methods, preparation of organic compounds, chemical industry and other directions, which can solve the problems of unsuitability for general application, unsuitable long-term use, complicated distillation process, etc. The effect of large-scale production, environmental protection and large amount of purification

Inactive Publication Date: 2012-01-18
印海平
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  • Abstract
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  • Claims
  • Application Information

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Problems solved by technology

Most of the extractants used in the high-pressure distillation of extractants are organic solvents and the rectification process is complicated. For example, the extractant used in Chinese patent "200710022224.2" is polyethylene glycol dimethyl ether. The extractant is not only expensive, but also Pollution is strong, not suitable for a large number of long-term use
[0005] The method of gas-liquid countercurrent, such as the Chinese patent "95195524.1", uses polyalkylene or its derivatives for gas-liquid countercurrent contact to purify methylal. This method requires high equipment requirements, high input costs, and complicated operations. , not suitable for general application

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  • Method for purifying methylal
  • Method for purifying methylal
  • Method for purifying methylal

Examples

Experimental program
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Effect test

Embodiment 1

[0019] 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.

Embodiment 2

[0021] 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, after drying, filter 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.

Embodiment 3

[0023] 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.

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Abstract

The invention relates to a method for purifying methylal. The method comprises the following steps of: adding water into methylal of which the mass concentration is less than 95 percent and uniformly stirring, wherein the added water is 0.1-3 times the weight of the methylal; standing for 20-40 minutes for layering; adding a drying agent into an upper layer for drying, and stirring for 5-15 minutes, wherein the water sucking weight of the added drying agent is 1-12 times the wet weight of the methylal in the upper layer; and drying, and filtering the drying agent out to obtain the methylal of which the mass concentration is more than 99.5 percent, wherein the water-containing drying agent can be recycled by dehydrating. The method has the advantages: water is added into the methylal for extracting, and water is taken as an extracting agent, so that the cost is low, the purifying process is simple, the condition is mild, the purifying amount is large, industrial continuous production is facilitated, the mass concentration is stable and reliable, and other impurities are eliminated. The methylal is purified in a way of rectifying with a high-pressure rectifying system, so that the requirement on raw material quality is low, the purifying yield is high, the energy demand is low, industrial continuous production is facilitated, harmful substances are not discharged, and environmental protection is facilitated.

Description

technical field [0001] The invention relates to a method for purifying methylal with an extractant. [0002] The invention also relates to a method for purifying methylal with a high-pressure rectification system. Background technique [0003] The production process of methylal is to react methanol and formaldehyde under the condition of catalyst, and then obtain methylal through rectification. Since methylal and methanol azeotrope, there is methanol in the obtained methylal, the purity is not high, and the highest mass concentration is not too much as 92%. Such methylal can only be used in low-efficiency paint solvents and fuel additives, which greatly limits the application fields of methylal, while high-quality concentration of methylal has a wide range of applications. [0004] At present, most of the purification methods of methylal adopt the method of high-pressure rectification of extractant and gas-liquid countercurrent. Most of the extractants used in the high-...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C43/30C07C41/58C07C31/04C07C29/80
CPCY02P20/10Y02P20/52
Inventor 印海平
Owner 印海平
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