Method for preparing methylal using combined continuous distillation and liquid-liquid extraction

A technology of reactive distillation and methylal, applied in chemical instruments and methods, preparation of organic compounds, organic chemistry, etc., can solve the problems of long production cycle, low yield, complex process, etc., and achieve short reaction cycle and high yield. High rate and high purity effect

Inactive Publication Date: 2006-07-26
NANJING NORMAL UNIVERSITY
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Problems solved by technology

[0002] The traditional methylal synthesis process adopts the following four methods: dichloromethane is the earliest method for synthesizing methylal. Due to backward technology and low yield, this method has no industrialization; dimethyl sulfoxide method, due to dimethyl sulfoxide Sulfone is unstable to acid, and formaldehyde will be generated when heated, so there is no industrialization; the calcium chloride method, the reaction yield can reach 86.5%, but due to the long reaction time and inconvenient post-treatment, so there is no industrialization; acid-catalyzed batch method, yield

Method used

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  • Method for preparing methylal using combined continuous distillation and liquid-liquid extraction
  • Method for preparing methylal using combined continuous distillation and liquid-liquid extraction
  • Method for preparing methylal using combined continuous distillation and liquid-liquid extraction

Examples

Experimental program
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Effect test

Embodiment 1

[0022] Embodiment 1, continuous reaction rectification and liquid-liquid extraction combine to prepare methylal process, with reference to Fig. 1: 37~40% formaldehyde presses the speed of 68ml / min, toluenesulfonic acid catalyst presses 5.5% of reaction mass total amount (mass ratio) is added in reactor 1, and 99.5% methanol is added from the 5th piece of rectification column 4 (feed position can be adjusted), and adding V / V is 101ml / min, after reaction rectification, tower top must distill The liquid contains relatively high methylal, methanol and water, and glycerol is used as the extraction agent, and the liquid-liquid extraction tower 5 extracts, and the methylal content at the top of the extraction tower can reach more than 99.7%. The extractant and the methanol-water mixture are recycled through the regeneration tower 6 for recycling. The methanol and water at the top of the regenerated tower can be further recycled and processed. The temperature of the reactor and top o...

Embodiment 2

[0023] Example 2 is basically the same as Example 1, but the catalyst is changed to sulfuric acid, and the extractant is changed to dimethylamine; the methanol / formaldehyde volume flow ratio is 1.4:1.

Embodiment 3

[0024] Embodiment 3 is substantially the same as Embodiment 1, but the methanol / formaldehyde volume flow ratio is 1.6:1.

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Abstract

The preparation technique combined continual reaction rectification and liquid-liquid extraction for methylal comprises: one-time adding the catalyst of toluenesulfonic acid and formaldehyde into reaction kettle as well as methanol from rectification column; controlling the temperatures of kettle and top of reaction rectification device within 50~55Deg and 35~42Deg respectively; then, with glycerin or bicarbinolamine as extractant, taking liquid-liquid extraction to the distillate from tower top with 92% methylal and 6% methanol and 2% water to obtain the methylal on tower top; recovering the extractant and methanol-water mixture for cycle. This invention has yield more than 97% with short reaction period and fast speed.

Description

technical field [0001] The invention relates to an organic chemical process, in particular to a method for preparing methylal by combining continuous reactive distillation and liquid-liquid extraction. Background technique [0002] The traditional methylal synthesis process adopts the following four methods: dichloromethane is the earliest method for synthesizing methylal. Due to backward technology and low yield, this method is not industrialized; dimethyl sulfoxide method, due to dimethyl sulfoxide Sulfone is unstable to acid, and formaldehyde will be generated when heated, so there is no industrialization; the calcium chloride method, the reaction yield can reach 86.5%, but due to the long reaction time and inconvenient post-treatment, so there is no industrialization; acid-catalyzed batch method, yield The production rate is relatively low, the production cycle is long, and the energy consumption is high, but the main way to produce methylal in my country, the content is a...

Claims

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Application Information

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IPC IPC(8): C07C41/48C07C43/303
Inventor 顾正桂
Owner NANJING NORMAL UNIVERSITY
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