A kind of method for synthesizing cyclopentanimide

A technology of cyclopentanimide and a synthesis method, applied in the direction of organic chemistry and the like, can solve the problems of poor appearance black and yellow quality, poor utilization effect, and high utilization cost, and achieve stable reaction process conditions, stable reaction and quality, and product quality. Stable quality effect

Active Publication Date: 2019-11-19
JINAN ASIA PHARMA TECH +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] Although this synthesis method involves fewer processes, there is no synthesis link of other intermediates, and it can be synthesized in one step, there are still many shortcomings in actual production: 1. The product ring closure requires special equipment, and it is not easy to stir and disperse pure solids. Thermal difficulties affect the quality of the product, and there are high safety risks in actual production; 2. Because direct ring closure requires a high temperature above 250°C, the product is easy to carbonize at such a high temperature, and the appearance is black and yellow and the quality is poor; 3. The product yield is about 50%-60%, the yield is low, and a large amount of waste residue will be generated during the production process, which seriously pollutes the environment and causes waste of resources
[0005] In addition, although there are also some synthesis processes that first hydrolyze the diamide into an acid, then anhydride the acid anhydride, and then ammoniate the acid anhydride with ammonia to obtain cyclopentanimide, these processes still rely on high-temperature cyclopentanimide. To complete, did not solve the coking problem of the product at high temperature
In addition, the excessive reaction components or the impurities produced have not been effectively utilized, or the utilization cost is high, and the utilization effect is not good.

Method used

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  • A kind of method for synthesizing cyclopentanimide

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Experimental program
Comparison scheme
Effect test

Embodiment 1

[0024] Add water and 1,2-cyclopentane diamide into the reaction kettle at a mass ratio of 1:1, dissolve, heat up to 95-105°C and reflux, start adding 40% sodium hydroxide solution dropwise, 1,2-cyclopentane The mass ratio of sodium hydroxide in glutanediamide to sodium hydroxide solution is 5:2-4, stop after dropping for about 1-3 hours, continue stirring for 30-60 minutes, when no tail gas is released, the reaction ends;

[0025] After the reaction is completed, cool down. When the temperature drops to 20-35°C, start to add concentrated hydrochloric acid for acidification. Measure the pH in the reactor. Stop when the pH is 1-2. When the acidification is complete, cool the reactor to 0-5°C and continue stirring. After 1 hour, the reactant was filtered, washed with water, and air-dried at 45-60°C to obtain 1,2-cyclopentanedioic acid;

[0026] Add 1,2-cyclopentanedioic acid and formamide into the reactor at a mass ratio of 1:2~4 and mix them. After nitrogen replacement, heat up ...

Embodiment 2

[0029] Stir mechanically in a 250mL four-necked bottle, add 60g of drinking water and 60g of 1,2-cyclopentane diamide, heat up to 100°C and reflux, start adding 90g of 40% sodium hydroxide solution dropwise, the reaction will release ammonia gas, continue stirring after the dropwise addition is complete 30min, when no tail gas is emitted, the reaction ends;

[0030] After the reaction is completed, cool down. When the temperature is 25°C, add 120g of 36% concentrated hydrochloric acid dropwise for acidification. Measure the pH. When the pH is 2, the acidification is complete. Stop the dropwise addition. After cooling down to 0°C in an ice bath, continue to stir for 1 hour and filter. Washed with water and blown dry at 55°C to obtain 57.3g of 1,2-cyclopentanedioic acid with a yield of 95.5%;

[0031] Mix 50g of 1,2-cyclopentanedioic acid and 20g of formamide, replace with nitrogen, and raise the temperature to an internal temperature of 150°C for reaction. During the reaction, ...

Embodiment 3

[0034] Stir mechanically in a 250mL four-neck bottle, add 60g of drinking water and 60g of 1,2-cyclopentane diamide, dissolve, heat up to 95°C and reflux, add 100g of 40% sodium hydroxide solution dropwise, and continue stirring for 60min after the addition is complete. When the tail gas is released, the reaction ends;

[0035] After the reaction is completed, cool down. When the temperature is 35°C, add 120g of 36% concentrated hydrochloric acid dropwise for acidification. When the pH of the mixed solution is measured to be 1-2, the acidification is completed. After cooling down to 5°C in an ice bath, continue stirring for 1 hour, filter, and wash with water for 60 ℃ blast drying to obtain 58g of 1,2-cyclopentadioic acid with a yield of 96.7%;

[0036] Mix 50g of 1,2-cyclopentanedioic acid and 28g of formamide, replace with nitrogen, and raise the temperature to an internal temperature of 200°C to react. During the reaction, the low boilers are distilled out. During the react...

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Abstract

The invention relates to a method for synthesizing cyclopentyl imide. The method comprises the following steps: reacting a raw material 1,2-cyclopentanediamide with an alkali liquid to generate 1,2-cyclopentanediacid, and reacting the 1,2-cyclopentanediacid with methanamide to generate the cyclopentyl imide. The synthesis method greatly reduces the cyclopentyl imide synthesis temperature to make the reaction mildly proceed, so the high temperature problem in the prior art is solved, the safety in the production process is improved, and energy saving and consumption reduction are realized; and the method has the advantages of liquid and homogenous synthesis system, stable reaction and quality, low temperature reaction conditions, no generation of coking, oxidation or carbonizing waste resides or other impurities, improvement of the quality of the above product, realization of the continuous primary yield reaching 90% or above and being about 10-30% higher than that of present technologies, stable reaction technology conditions, easiness in control, and high reaction conversion rate.

Description

technical field [0001] The invention relates to the technical field of synthesis of pharmaceutical intermediates, in particular to a method for synthesizing cyclopentanimide. Background technique [0002] At present, most of the synthesis methods of cyclopentanimide are 1,2-cyclopentane diamide direct high-temperature cyclization to generate cyclopentanimide. The technical route is as follows: [0003] , [0004] Although this synthesis method involves fewer processes, there is no synthesis link of other intermediates, and it can be synthesized in one step, there are still many shortcomings in actual production: 1. The product ring closure requires special equipment, and it is not easy to stir and disperse pure solids. Thermal difficulties affect the quality of the product, and there are high safety risks in actual production; 2. Because direct ring closure requires a high temperature above 250°C, the product is easy to carbonize at such a high temperature, and the appear...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C07D209/52
CPCC07D209/52
Inventor 孙彬彭立增姬松涛王伟
Owner JINAN ASIA PHARMA TECH
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