Unlock instant, AI-driven research and patent intelligence for your innovation.

A kind of preparation method of 3-fluoropyridine

A technology of fluoropyridine and aminopyridine, which is applied in the field of preparation of 3-fluoropyridine, can solve problems such as explosion, low yield, and potential safety hazards, and achieve the effects of increasing reaction yield, high yield, and slow heat release

Active Publication Date: 2019-04-12
ANHUI XINGYU CHEM
View PDF5 Cites 0 Cited by
  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0009] Aiming at the problems of low yield and potential safety hazard of explosion in the existing diazotization method, the present invention provides a method for preparing 3-fluoropyridine, using a water-absorbing agent DCC (i.e., N,N'-di Cyclohexylcarbodiimide), breaking through the existing technical bottleneck, while ensuring high yield and high content of 3-fluoropyridine, the risk of the reaction is significantly reduced, and the water-absorbing agent used will not affect the product secondary pollution

Method used

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
View more

Image

Smart Image Click on the blue labels to locate them in the text.
Viewing Examples
Smart Image
  • A kind of preparation method of 3-fluoropyridine

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0038] In view of the existing diazotization method to prepare 3-fluoropyridine, there are great potential safety hazards and shortcomings such as low yield, step-by-step operation, and strong reaction corrosion. This example provides a safe and efficient method for preparing 3-fluoropyridine The process route, concrete steps are:

[0039] Add 26 kg of 3-aminopyridine and 128 kg of 50% (mass fraction) fluoroboric acid into the reactor and stir evenly. The stirring speed is controlled at about 100 rpm. Nitrogen gas is introduced into the reactor to drive away the oxygen in the reactor. Under conditions, add 25kg of sodium nitrite while stirring, and add a water-absorbing agent (15% of the mass of sodium nitrite) at the same time. The agent contains catalyst TEBA (benzyltriethylammonium chloride) and octadecadecrown-6, and TEBA accounts for 1% of the mass of the water-absorbing agent; octadecadecrown-6 accounts for 0.5% of the mass of the water-absorbing agent; after the reactio...

Embodiment 2

[0042] In view of the existing diazotization method to prepare 3-fluoropyridine, there are great potential safety hazards and shortcomings such as low yield, step-by-step operation, and strong reaction corrosion. This example provides a safe and efficient method for preparing 3-fluoropyridine The process route, concrete steps are:

[0043] Add 26kg of 3-aminopyridine and 98kg of 50% (mass fraction) fluoroboric acid into the reactor and stir evenly, the stirring speed is controlled at about 100rpm, feed nitrogen into the reactor to drive away the oxygen of the reactor, and then Under the conditions, add 21.7 kg of sodium nitrite while stirring, and add a water-absorbing agent (10% of the mass of sodium nitrite) at the same time. The water-absorbing agent contains catalyst TEBA (benzyltriethylammonium chloride) and octadecyl crown-6, and TEBA accounts for 1% of the mass of the water-absorbing agent; octadecyl-crown-6 accounts for 0.5% of the mass of the water-absorbing agent; th...

Embodiment 3

[0046] In view of the existing diazotization method to prepare 3-fluoropyridine, there are great potential safety hazards and shortcomings such as low yield, step-by-step operation, and strong reaction corrosion. This example provides a safe and efficient method for preparing 3-fluoropyridine The process route, concrete steps are:

[0047] Add 18kg of 3-aminopyridine and 75kg of 50% (mass fraction) fluoboric acid into the reactor and stir evenly, the stirring speed is controlled at about 100rpm, feed nitrogen into the reactor to drive away the oxygen of the reactor, and then Under the conditions, add 15 kg of sodium nitrite while stirring, and add a water-absorbing agent (8% of the mass of sodium nitrite) at the same time. The agent contains catalyst TEBA (benzyltriethylammonium chloride) and octadecadecrown-6, and TEBA accounts for 1% of the mass of the water-absorbing agent; octadecadecrown-6 accounts for 0.5% of the mass of the water-absorbing agent; after the reaction Rai...

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to View More

PUM

No PUM Login to View More

Abstract

The invention discloses a 3-fluoropyridine preparation method high in yield and content, and belongs to the technical field of compound synthesis. The 3-fluoropyridine preparation method is capable of solving problems in the prior art that yield is low, and explosion potential safety hazard exists. According to the 3-fluoropyridine preparation method, one-step synthesis is adopted, reaction of a water absorbent with an appropriate catalyst is adopted for the first time, distillation is adopted for decoloration and purifying, reaction temperature is reduced obviously, heat release is slowed obviously, no special operation is needed in operation process, reaction yield is increased obviously, yield is increased to be three times of that of conventional diazotization method, reaction safety is increased greatly, the 3-fluoropyridine preparation method is an industrialized production method high in safety and yield is high, and low in cost; study choke point of conventional diazotization method is broken; and a novel method is provided for synthesis of fluorinated pyridine intermediates.

Description

technical field [0001] The invention belongs to the technical field of compound synthesis, and more specifically relates to a method for preparing 3-fluoropyridine with high yield and high content. Background technique [0002] Fluorine-substituted pyridine intermediates are an important class of pharmaceutical and pesticide intermediates, such as 2-fluoropyridine (CAS 327-48-5), 3-fluoropyridine (CAS 372-47-4) and so on. Pyridine has a certain basicity, its properties are somewhat similar to nitrobenzene, and its chemical properties are mainly reflected in the substitution reaction on the pyridine ring and the basicity and nucleophilicity of the unpaired electrons on the nitrogen. The methods currently used to synthesize fluorine-substituted pyridine intermediates mainly include fluorodenitration, direct fluorination, halogen exchange, and diazotization. [0003] In recent years, studies have found that denitrification of fluorine provides a new way to synthesize fluorine-...

Claims

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to View More

Application Information

Patent Timeline
no application Login to View More
Patent Type & Authority Patents(China)
IPC IPC(8): C07D213/61
CPCC07D213/61
Inventor 张宽宇司景张升
Owner ANHUI XINGYU CHEM