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A kind of method that catalytic nitration synthesizes mononitro-o-xylene in microreactor

A technology of nitro-ortho-xylene and ortho-xylene, applied in the preparation of nitro compounds, organic chemistry, etc., can solve the problems of unsuitability for large-scale industrial production, high price of perfluorosulfonic acid resin, and low economic applicability. Achieve good industrial application prospects, easy integration and amplification, and fast heat transfer effects

Active Publication Date: 2017-02-08
NANJING UNIV OF SCI & TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Olah et al. (Olah G. A. Communications, 1978, 9: 690-691) have found that using perfluorosulfonic acid resin as a catalyst, the dosage is 10% ~ 25%, and butyl nitrate is the condition of nitrating agent to obtain the best yield 4-NOX accounts for 53% of the total nitration products, and 3-NOX accounts for 47%. The isomer ratio of this product is not much different from that of the nitric-sulfur mixed acid system, and the perfluorosulfonic acid resin is relatively expensive and economically applicable. not tall
Jingdan et al. (Jingdan. Modern Chemicals. 2010, 20(2), 223-225) investigated the P 2 o 5 The selectivity of o-xylene nitration under P 2 o 5 When the mass fraction is 4.5%, the molar ratio of nitric acid and o-xylene is 1.15, the dehydration value of sulfuric acid (D.V.S) is 3.16, the reaction temperature is 20°C, and the reaction time is 4 h, the molar ratio of 3-NOX to 4-NOX in the nitration product reaches 0.94, compared with The 1.35 of nitric-sulfur mixed acid is significantly reduced, and the conversion rate of o-xylene reaches 97.6%; but P 2 o 5 Corrosive to equipment, not suitable for large-scale industrial production

Method used

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  • A kind of method that catalytic nitration synthesizes mononitro-o-xylene in microreactor
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  • A kind of method that catalytic nitration synthesizes mononitro-o-xylene in microreactor

Examples

Experimental program
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Embodiment 1

[0029] Dissolve a certain amount of rare earth metal trifluoromethanesulfonate in 95% fuming nitric acid at room temperature, and inject the acid phase and organic phase solution into the microchannel reactor through a high-pressure constant-flow pump under the condition of a constant temperature water bath at 80°C. Control the mol ratio of nitric acid and o-xylene to be 2:1, o-xylene and trifluoromethanesulfonic acid rare earth metal salt (Y(OTf) 3 ) The molar ratio is 10:1. After 180s of reaction, the reaction product flows out of the reactor continuously and is collected in the collector at room temperature. 2 Cl 2 Extraction, static layering, after liquid separation, the organic phase layer was washed with alkali, water and saturated NaCl solution to neutrality, and then washed with Mg 2 SO 4 After drying, the reaction conversion rate is 90.1%, the proportion of 3-NOX is 33.53%, the proportion of 4-NOX is 66.47%, and the ratio of 4-NOX / 3-NOX is 1.98. The water phase was...

Embodiment 2

[0031] Process is the same as embodiment 1, does not change the mol ratio of nitric acid and o-xylene, changes the mol ratio of o-xylene and rare earth metal salt to be 20:1, according to this feed reaction, through gas phase detection, the reaction conversion rate is 83.1%, The proportion of 3-NOX is 35.49%, the proportion of 4-NOX is 64.51%, and the ratio of 4-NOX / 3-NOX is 1.82.

Embodiment 3

[0033] The process is the same as in Example 1, only changing the mol ratio of nitric acid and o-xylene, the mol ratio of nitric acid and o-xylene is 1:1, according to this feed reaction, through gas phase detection, the reaction conversion rate is 54.3%, 3-NOX The proportion is 37.03%, the proportion of 4-NOX is 62.97%, and the ratio of 4-NOX / 3-NOX is 1.70.

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Abstract

The invention discloses a method for synthesizing single nitro-o-xylene employing catalytic nitration in a micro-reactor. The used catalyst is a rare-earth metal salt; the raw materials are o-xylene and nitric acid; and the raw materials are injected into a micro-channel reactor to be nitrified by a high-pressure constant flow pump at ordinary pressure. The method is free of a solvent; and the reinforcing action of the micro-channel reactor on quality and heat transfer processes is well utilized.

Description

technical field [0001] The invention belongs to the field of organic synthesis and relates to the synthesis of mononitro-o-xylene, specifically a method utilizing HNO 3 As a nitrating agent, a rare earth metal trifluoromethanesulfonate is used as a catalyst to catalyze the nitration reaction of o-xylene, and a method for synthesizing mononitro-o-xylene by catalytic nitration in a microchannel reactor. Background technique [0002] Two kinds of mononitration products can be obtained through nitration of o-xylene, which are 3-nitro-o-xylene (3-NOX) and 4-nitro-o-xylene (4-NOX), among which 4-nitro-o-xylene is a new type Herbicide pendimethalin and vitamin B 2 It is also widely used in pesticides, medicines and dyes. [0003] Traditionally, most of them are synthesized by nitric acid mixed acid nitration method of o-xylene. This method has the characteristics of high nitrification ability, fast speed, etc., but the method has poor regioselectivity, and 4-nitro-o-xylene only a...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C07C205/06C07C201/08
Inventor 李斌栋汪欢滕裕翔常婷
Owner NANJING UNIV OF SCI & TECH