Method for recovering pyridine from aqueous solution

A technology of aqueous solution and pyridine, which is applied in the field of drug synthesis, can solve the problems of high cost, high energy consumption of pyridine, and low efficiency, and achieve the effects of low environmental pressure, simple operation, and waste reduction

Inactive Publication Date: 2014-08-20
SHANGHAI NEW HUALIAN PHARMA
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] The object of the present invention provides a kind of method that reclaims pyridine from aqueous solution, and this method can reduce the moisture of system during distillation greatly, can reduce the waste of resources, do not pollute environment again, can also reduce production cost, thus has solved the problem of pyridine from aqueous solution The problems of high energy consumption, high cost and low efficiency in recovering pyridine

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0021] Embodiment 1, reclaim pyridine from the aqueous solution of synthesizing isotretinoin

[0022] The content of pyridine in the pyridine aqueous solution of this embodiment is 30%, which comes from the aqueous solution of synthesizing isotretinoin.

[0023] 1. Adjust acidity

[0024] In a 5L beaker, put 3.5L of 30% pyridine aqueous solution, add 30% hydrochloric acid to adjust pH=1;

[0025] 2. Cyclohexane extraction

[0026] Add the solution in step 1 to a 5L separatory funnel, extract with 500ml cyclohexane each time until the pyridine content in the water layer is less than 0.5%, and collect the obtained organic phase for later use;

[0027] 3. Alkali adjustment and liquid separation

[0028] Combine the organic phases in step 2, adjust the pH to greater than 12 with 50% sodium hydroxide solution, separate the alkaline water layer, and apply mechanically;

[0029] 4. Backflow water separation

[0030] Put the solution of step 3 into a 1L four-neck flask, reflux an...

Embodiment 2

[0031] Embodiment 2, reclaim pyridine from the aqueous solution of synthesizing isotretinoin

[0032] The content of pyridine in the pyridine aqueous solution of this embodiment is 30%, which comes from the aqueous solution of synthesizing isotretinoin.

[0033] 1. Adjust acidity

[0034] In a 500L reactor, put 300L of 30% pyridine aqueous solution into it, and add 30% hydrochloric acid to adjust the pH to 1;

[0035] 2. Cyclohexane extraction

[0036] Extract the solution in step 1 with 30-50L cyclohexane each time until the pyridine content in the water layer is less than 0.5%, and collect the obtained organic phase for later use;

[0037] 3. Alkali adjustment and liquid separation

[0038] Combine the organic phases in step 2, adjust the pH to greater than 12 with 50% sodium hydroxide solution, separate the alkaline water layer, and apply mechanically;

[0039] 4. Backflow water separation

[0040] After the solution in step 3 was refluxed to divide the water until the...

Embodiment 3

[0041] Embodiment 3, reclaim pyridine from the aqueous solution of synthesizing isotretinoin

[0042] The content of pyridine in the pyridine aqueous solution of this embodiment is 30%, which comes from the aqueous solution of synthesizing isotretinoin.

[0043] 1. Adjust acidity

[0044] In a 2000L reactor, put 1600L of 30% pyridine aqueous solution into it, and add 30% hydrochloric acid to adjust the pH=1;

[0045] 2. Cyclohexane extraction

[0046] Extract the solution in step 1 with 100-200L cyclohexane each time until the pyridine content in the water layer is less than 0.5%, and collect the obtained organic phase for later use;

[0047] 3. Alkali adjustment and liquid separation

[0048] Combine the organic phases in step 2, adjust the pH to greater than 12 with 50% sodium hydroxide solution, separate the alkaline water layer, and apply mechanically;

[0049] 4) Backflow water separation

[0050] After the solution of step 3 is refluxed to separate water to no obvio...

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PUM

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Abstract

The invention relates to a method for recovering pyridine from an aqueous solution. The method comprises the following steps: adjusting the pH value of a pyridine aqueous solution system to 1 by using hydrochloric acid; extracting pyridine by using cyclohexane and then adjusting the pH value to more than 12 by using sodium hydroxide; after an alkaline water layer is separated, carrying out reflux and water separation until there is no obvious water and then carrying out normal pressure rectification; and finally, carrying out distillation so as to obtain high-purity pyridine and recovering cyclohexane. The method provided by the invention has the advantages of simple operation, high efficiency, small environment stress and applicability to recovery of an aqueous pyridine solution with a concentration of 5 to 48%.

Description

technical field [0001] The invention relates to the technical field of drug synthesis, in particular to a method for recovering pyridine from an aqueous solution. Background technique [0002] Pyridine is a six-membered heterocyclic compound containing a nitrogen heteroatom. It can be regarded as a compound in which one (CH) in the benzene molecule is replaced by N, so it is also called nitrogen benzene. It is a colorless or slightly yellow liquid with a foul smell. It is a drug Organic bases, catalysts, solvents and raw materials commonly used in synthesis. [0003] At present, pyridine is less produced domestically, and most of it depends on imports. If pyridine is recovered from waste liquid, it will not only alleviate the problem of insufficient supply of pyridine, but also reduce the harm of waste liquid to the environment and save costs. Since pyridine forms an azeotrope with water and has a high solubility in water, when the content of pyridine in water is low, it i...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07D213/16C07D213/127
CPCC07D213/16C07D213/127
Inventor 宣闵吴庆安周秋火
Owner SHANGHAI NEW HUALIAN PHARMA
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