Preparation method for methyl nitrite

A technology of methyl nitrite and nitric acid, which is applied in the field of preparation of methyl nitrite, can solve the problems of no nitrite and can not completely eliminate the generation and discharge of nitric acid, so as to improve the yield, reduce the heat supply of the tower kettle, Conducive to the effect of environmental protection requirements

Active Publication Date: 2013-10-30
PUJING CHEM IND SHA +1
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  • Summary
  • Abstract
  • Description
  • Claims
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Problems solved by technology

[0013] But the reaction is carried out in two reaction devices respectively; in addition United States United Carbide Corporation (US4908466, US4353843), domestic Tianjin University (CN101314569A) etc. have also carried out relevant research, but the key point of its research mainly concentrates on how to control the degree of reaction, Reduce the generation of by-product nitric acid and refine methyl nitrite products, etc. The entire process cannot completely eliminate the generation and discharge of nitric acid
On the other hand, because nitrite has a certain solubility in methanol, a certain amount of nitrite will inevitably be contained in the liquid phase discharged from the traditional esterification tower, but how to reduce or Avoid the part where nitrites are almost non-existent

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  • Preparation method for methyl nitrite
  • Preparation method for methyl nitrite
  • Preparation method for methyl nitrite

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0041] A flow of 100kmol / hr containing NO gas (wherein NO content 14vol%, the rest is N 2 ) and O 2 After the reaction, 6vol% N 2 o 3 , the mixed gas containing 2vol% NO and nitrogen (the rest) enters the reaction section of the esterification tower, and is in countercurrent contact with methanol, water and nitric acid flowing down from top to bottom, and another stream of NO-containing gas with a flow rate of 20kmol / hr (the content of NO is 14vol%, and the rest is N 2 ) flows from the bottom of the stripping section, that is, the bottom of the esterification tower, to the reaction section from bottom to top. The pressure of the esterification tower kettle is 400KPa, and the temperature is 79°C. The gas discharged from the top of the esterification tower is a mixture of MN, NO and nitrogen.

[0042] A large amount of methanol-containing nitric acid wastewater produced in the esterification tower and tower kettle, part of which is directly refluxed to the bottom reaction s...

Embodiment 2

[0045] A flow of 100kmol / hr containing NO gas (wherein NO content 14vol%, MN content is 4vol%, the rest is N 2 ) and O 2 After the reaction, 6vol% N 2 o 3 , containing 2vol% NO, containing 4vol% MN, and the mixed gas of nitrogen (the rest), enters the reaction section of the esterification tower, and contacts with the methanol, water and nitric acid flowing down from top to bottom, and the other flow is 20kmol / hr of NO-containing gas (the content of NO is 14vol%, the content of MN is 4vol%, and the rest is N 2 ) flows from the bottom of the stripping section, that is, the bottom of the esterification tower, to the reaction section from bottom to top. The pressure of the esterification tower is 300KPa, and the temperature is 73°C. The gas discharged from the top of the esterification tower is a mixture of MN, NO and nitrogen.

[0046] A large amount of methanol-containing nitric acid wastewater produced in the esterification tower reactor, part of which is directly reflux...

Embodiment 4

[0057] A preparation method of methyl nitrite, specifically comprising the following steps:

[0058] a) Mix the first stream of NO-containing gas with O 2 Directly input into the reaction section of the esterification tower, methanol is input from the top of the esterification tower, and the second NO-containing gas is input from the bottom of the esterification tower;

[0059] b) The gas in the reaction section of the esterification tower flows through the reaction section from bottom to top, reacts with the methanol flowing down from top to bottom for esterification reaction, and generates methyl nitrite, water and by-product nitric acid;

[0060] c) The liquid phase mixture of nitric acid, methanol and water flowing down from the reaction section of the esterification tower and the methyl nitrite dissolved in the liquid phase mixture enter the gas stripping section of the esterification tower, and carry out countercurrent with the second stream of NO-containing gas Contact...

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Abstract

The invention relates to a preparation method for methyl nitrite. The preparation method is characterized by comprising the following steps of: taking NO-containing gas, O2 and methanol as raw materials, inputting the NO-containing gas, the O2 and the methanol into at least one esterification column, reacting to obtain methyl nitrite, and recycling nitric acid and the residual methanol, wherein the residual methanol is recycled in at least one methanol recycling column, and the nitric acid is recycled in at least one nitric acid recycling column. Compared with the prior art, the preparation method for the methyl nitrite has the advantages that MN can be effectively generated, the NO conversion rate can be improved, the yield of the MN can be increased, the heating capacity of the bottom of the esterification column can be reduced, and the wastewater discharged from a system does not contain the nitric acid; the problem of the nitric acid wastewater generated in a process for generating methyl nitrite from NO is thoroughly solved, and the preparation method is beneficial to environmental protection and has a good practical application value and production significance.

Description

technical field [0001] The present invention relates to a kind of preparation method of methyl nitrite. Background technique [0002] In the process of coal-to-ethylene glycol, methyl nitrite is used as an intermediate circulating substance, CO is coupled into oxalate, and then ethylene glycol is obtained through hydrogenation reaction, which has initially realized the industrial production of ethylene glycol. new coal chemical route. The entire process route is as follows: [0003] 2NO+0.5O 2 +2CH 3 OH→2CH 3 ONO+H 2 O equation (1) [0004] 2CO+2CH 3 ONO→(CH 3 OCO) 2 +2NO equation(2) [0005] (CH 3 OCO) 2 +4H 2 →CH 2 OHCH 2 OH+2CH 3 OH equation (3) [0006] During the whole cycle, NO and methanol are theoretically not lost, and the overall reaction formula is: [0007] 2CO+0.5O 2 +4H 2 →CH 2 OHCH 2 OH+H 2 O equation (4) [0008] However, in the actual production process, especially in the engineering of generating methyl nitrite, some by-products will...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C203/00C07C201/04
Inventor 骆念军毛彦鹏计扬张博李伟
Owner PUJING CHEM IND SHA
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