Method for continuously synthesizing 2-ethylhexyl nitrate in micro-reactors and extracting residual acid in 2-ethylhexyl nitrate

Abstract

The invention relates to a method for continuously synthesizing 2-ethylhexyl nitrate in micro-reactors and extracting residual acid in the 2-ethylhexyl nitrate. The method for continuously synthesizing the 2-ethylhexyl nitrate in the micro-reactors and extracting the residual acid in the 2-ethylhexyl nitrate comprises the following steps: with isooctanol and a mixed acid, with a molar ratio of sulfuric acid to nitric acid ranging from 1.5 to 2.5, as raw materials, carrying out a nitration reaction in a first micro-reactor to generate 2-ethylhexyl nitrate and a waste acid, and separating out anacid-containing 2-ethylhexyl nitrate crude product through a liquid-liquid automatic separator; and mixing the crude product and a NaOH aqueous solution in a second micro-reactor, then carrying out areaction to extract the residual acid in the 2-ethylhexyl nitratecrude product, and conducting water-oil separation to obtain the 2-ethylhexyl nitrate with an ultra low acid content. The extraction efficiency is higher than 96%. By means of the method for continuously synthesizing the 2-ethylhexyl nitrate in the micro-reactors and extracting the residual acid in the 2-ethylhexyl nitrate, continuous operation of synthesis of the 2-ethylhexyl nitrate and acid removal is achieved, the danger level is lowered, and the consumed time of acid removal is shortened, so that the production efficiency is improved.

Description

technical field [0001] The invention relates to a method for synthesizing and refining isooctyl nitrate, in particular to a method for continuously synthesizing isooctyl nitrate and removing residual acid in isooctyl nitrate using micro-reaction technology. Background technique [0002] Isooctyl nitrate (referred to as EHN) molecular formula: (C 8 h 17 O)NO 2 , also known as 2-ethylhexyl nitrate, is an important liquid energetic material in nitrate ester compounds, and is the most widely used and cost-effective diesel cetane number improver, which can participate in the degradation branch reaction of fuel before ignition , shortening the chemical flame-delay period of the fuel is of great significance to improving the performance of the fuel. [0003] In the production technology of existing isooctyl nitrate, generally adopt nitric acid mixed acid method in tank reactor, in the mode of slow dropwise, under the condition of normal temperature or lower than normal temperatu...

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Problems solved by technology

There are a series of problems and hidden dangers in this production technology: first, it takes a long time to add slowly, and the long production cycle limits its industrial application, so it is difficult to realize the synthesis of EHN quickly and efficiently; second, due to the addition of concentrated sulfuric acid or The conditions under which the mixed acid exists can reduce the initial decomposition temperature of isooctyl nitrate and increase the heat sensitivity. If it exceeds 30°C, there will be a danger of explosion. The local overheating phenomenon of the local overheating phenomenon cannot be completely avoided, and the side reactions and reaction out-of-control phenomena caused by it occur from time to time. There have been two such accidents in China; Then dry and remove water, the whole process is intermittent and cumbersome, consumes a lot of manpower and material resources, high production cost, low efficiency, and extremely dangerous

[0004] Invention patent application document CN 109280007 A discloses a method for continuously synthesizing isooctyl nitrate using a microreactor. The reaction temperature needs to be kept low. If the sulfur / nitrate ratio of nitric-sulfur mixed acid is too high, excessive waste acid will be produced, and the entire nitration and There are high energy consumption and high pollution problems in the process of extraction and acid removal

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