Method for preparing 2-methylallyl chloride from 1,2-dichloroisobutane

Patent metadata

Field	Value
Publication number	US-11319267-B2
Application number	US-201816759860-A
Country	US
Kind code	B2
Filing date	Oct 10, 2018
Priority date	Feb 9, 2018
Publication date	May 3, 2022
Grant date	May 3, 2022

Abstract

The present invention relates to a method for preparing 2-methylallyl chloride from 1,2-dichloroisobutane. The method is characterized in that 1,2-dichloroisobutane and a sodium hydroxide aqueous solution are used as raw materials; reactive rectification is performed in a combined rectifying tower to eliminate hydrogen chloride so as to obtain 2-methylallyl chloride. A plate tower is provided at the lower part of the combined rectifying tower; a packing tower is provided at the upper part of the combined rectifying tower; an inner reflux condenser is provided at the top of the combined rectifying tower. The sodium hydroxide aqueous solution is added from a first plate of the plate tower; and 1,2-dichloroisobutane is added from the middle part of the plate tower. The method has the advantages that the raw material 1 and 1,2-dichloroisobutane is fully converted; the selectivity of the 2-methylallyl chloride is high.

First claim

The invention claimed is:

1. A method for preparing 2-methallyl chloride from 1,2-dichloroisobutane, wherein 1,2-dichloroisobutane and a sodium hydroxide aqueous solution are used as raw materials, and react in a rectifying tower to eliminate hydrogen chloride, and the product 2-methallyl chloride is rectified from the top of the rectifying tower.

2. The method according to claim 1 , wherein the sodium hydroxide aqueous solution has a concentration of 10-20%; and a mass ratio of the sodium hydroxide aqueous solution to the 1,2-dichloroisobutane is 1.6-3.5:1.

3. The method according to claim 1 , wherein an azeotrope of 2-methallyl chloride and water is obtained from the top of the rectifying tower, and is layered by cooling to obtain 2-methallyl chloride.

4. The method according to claim 1 , wherein the rectifying tower is a combined rectifying tower, a plate tower is provided at the lower part of the combined rectifying tower; a packing tower is provided at the upper part of the combined rectifying tower; an inner reflux condenser is provided at the top of the combined rectifying tower; and a reboiler is provided at the bottom of the combined rectifying tower to provide a heat source.

5. The method according to claim 4 , wherein the number of plates in the plate tower on the lower part of the combined rectifying tower is 10-20; and the upper packing tower has 10-20 theoretical plates.

6. The method according to claim 5 , wherein a tray of the plate tower is a sieve tray, a bubble tray or a float valve tray; and the packing tower is structured packing or random packing.

7. The method according to claim 5 , wherein the sodium hydroxide aqueous solution is added from a first plate of the plate tower of the combined rectifying tower, and the 1,2-chloro-tert-butane is added from the fifth to fifteenth plates in the middle of the plate tower on the lower part of the combined rectifying tower.

8. The method of claim 1 , wherein the reflux ratio of a reflux in the tower top is controlled to 1-5.

Assignees

• Univ Zhejiang
• Zhejiang Huangma Tech Co Ltd

Inventors

• Chen Zhirong
• Yin Hong
• Wang Xinrong
• Jin Yifeng
• Zhao Xingjun
• Dong Nan
• Zhang Meijun
• Yu Yuanrong
• Zhang Yuejiang

Classifications

• C07C17/386

  with auxiliary compounds · CPC title

• C07C17/25 Primary

  by splitting-off hydrogen halides from halogenated hydrocarbons · CPC title

• C07C17/383

  by distillation · CPC title

• Y02P20/10

  Process efficiency · CPC title

• C07C21/067

  Allyl chloride; Methallyl chloride · CPC title