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Method for selectively reducing compounds of different chain lengths, especially boscalid intermediates to synthesize nitro compounds in mother liquor

A technology for boscalid and compounds, which is applied in the field of selective reduction of compounds with different chain lengths, and can solve problems such as economic losses, environmental hazards, and inability to achieve separation

Active Publication Date: 2022-04-12
兰升生物科技集团股份有限公司 +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0006] For example, in the current industrial production process of boscalid, the synthesis of its key intermediate 4'-chloro-2-nitro-1,1'-biphenyl (the synthetic route is shown below) in the post-treatment crystallization mother liquor, Contains a large amount of raw material o-chloronitrobenzene and product (4'-chloro-2-nitro-1,1'-biphenyl), which cannot be separated after other treatments such as recrystallization, resulting in large economic losses, and at the same time Waste liquid will cause certain harm to the environment

Method used

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  • Method for selectively reducing compounds of different chain lengths, especially boscalid intermediates to synthesize nitro compounds in mother liquor
  • Method for selectively reducing compounds of different chain lengths, especially boscalid intermediates to synthesize nitro compounds in mother liquor
  • Method for selectively reducing compounds of different chain lengths, especially boscalid intermediates to synthesize nitro compounds in mother liquor

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0045] Take 50g of untreated boscalid intermediate to synthesize mother liquor 1, and the content of 4'-chloro-2-nitro-1,1'-biphenyl is 32.5% (16.25g), and the content of o-chloronitrobenzene 37.6% (18.8 g).

[0046] Dissolve mother liquor 1 in 300mL of ethanol, based on the amount of o-chloronitrobenzene in the mother liquor, the amount of thiourea dioxide is 3.5 molar equivalents, the amount of sodium hydroxide is 8 molar equivalents, add sodium hydroxide solution, and stir for 10min Finally, add thiourea dioxide (purchased from Yantai Dasteco) in 5 batches within 1 hour, control the temperature between 10 and 15°C, and continue to react within this temperature range for 3 hours after adding thiourea dioxide Stop the reaction, carry out suction filtration, obtain filter cake and filtrate.

[0047] Treatment of the filter cake: add 50mL ethyl acetate to dissolve the organic matter, then add 50mL water to dissolve the salt, separate the liquid, continue to extract the water p...

Embodiment 2

[0053] Take 50g of untreated boscalid intermediate to synthesize mother liquor 2, and the content of 4'-chloro-2-nitro-1,1'-biphenyl is 31.95% (15.98g), and the content of o-chloronitrobenzene 36.91% (18.46g).

[0054] The reaction time was adjusted to 3.5 hours, and the others were operated in the same manner as in Example 1. The measurement results are shown in Table 2.

[0055] Table 2

[0056]

Embodiment 3

[0058] The untreated boscalid intermediate was used to synthesize the mother liquor 3, in which the content of o-chloronitrobenzene was 20.10%, and the content of 4'-chloro-2-nitro-1,1'-biphenyl was 38.88%.

[0059] Taking the amount of o-chloronitrobenzene in the mother liquor as a benchmark, the consumption of thiourea dioxide is 5 molar equivalents, and the consumption of sodium hydroxide is 8 molar equivalents, and the others are operated in the same way as in Example 1.

[0060] The reaction was monitored by TLC, and the o-chloronitrobenzene was significantly reduced faster, and the 4'-chloro-2-nitro-1,1'-biphenyl was obviously decreased slowly. When the reaction time was 150 minutes, the o-chloronitrobenzene There is a small amount of phenylbenzene remaining, but at this time 4'-chloro-2-amino-1,1'-biphenyl has been generated, and the reaction continues, and more 4'-chloro-2-amino-1, 1'-biphenyl. So under this condition, the optimal reaction time is 150min.

[0061] Af...

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Abstract

The invention relates to a method for selectively reducing compounds with different chain lengths, characterized in that thiourea dioxide is used as a reducing agent. The invention also relates to the use of thiourea dioxide as a selective reducing agent for compounds of different chain lengths. The compounds of different chain lengths are preferably nitro compounds of different chain lengths, more preferably nitro compounds with different numbers of aromatic rings (such as benzene rings), more preferably monophenyl nitro compounds and biphenyl nitro compounds, more preferably Further preferred are the nitro compounds 4'-chloro-2-nitro-1,1'-biphenyl and o-chloronitrobenzene in the mother liquor for the synthesis of boscalid intermediates. The present invention further relates to a method for improving the selectivity of thiourea dioxide as a reducing agent, which improves the reduction selectivity by adjusting the ratio of thiourea dioxide to the compound to be reduced, the reaction temperature and the reaction time.

Description

technical field [0001] The present invention relates to a method for selectively reducing compounds with different chain lengths, especially a method for selectively reducing nitro compounds with different chain lengths. More specifically, the present invention relates to a method for selectively reducing compounds with different numbers of aromatic rings (such as benzene rings), such as monophenyl nitro compounds and biphenyl nitro compounds, and further specifically relates to the selective reduction of boscalid The intermediate is a method for synthesizing nitro compounds in the mother liquor. Background technique [0002] Thiourea dioxide is a new type of reducing agent, which has been widely used due to its high reduction potential, good thermal stability, convenient storage and transportation, and many other advantages. [0003] Thiourea dioxide has a structure shown in the following formula A, which is prone to rearrangement and transformation into B when the alkalin...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C07C209/36C07C211/52
CPCC07C209/325C07C211/52
Inventor 董志鹏苑立刚郭庆春张志虎王浩郭红永宋海文王石华许峰刘海龙
Owner 兰升生物科技集团股份有限公司