CN110790701B - Process for preparing carboxylic acid by hydrolyzing nitrile compound - Google Patents
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- CN110790701B CN110790701B CN201910931751.8A CN201910931751A CN110790701B CN 110790701 B CN110790701 B CN 110790701B CN 201910931751 A CN201910931751 A CN 201910931751A CN 110790701 B CN110790701 B CN 110790701B
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- C07—ORGANIC CHEMISTRY
- C07D—HETEROCYCLIC COMPOUNDS
- C07D213/00—Heterocyclic compounds containing six-membered rings, not condensed with other rings, with one nitrogen atom as the only ring hetero atom and three or more double bonds between ring members or between ring members and non-ring members
- C07D213/02—Heterocyclic compounds containing six-membered rings, not condensed with other rings, with one nitrogen atom as the only ring hetero atom and three or more double bonds between ring members or between ring members and non-ring members having three double bonds between ring members or between ring members and non-ring members
- C07D213/04—Heterocyclic compounds containing six-membered rings, not condensed with other rings, with one nitrogen atom as the only ring hetero atom and three or more double bonds between ring members or between ring members and non-ring members having three double bonds between ring members or between ring members and non-ring members having no bond between the ring nitrogen atom and a non-ring member or having only hydrogen or carbon atoms directly attached to the ring nitrogen atom
- C07D213/60—Heterocyclic compounds containing six-membered rings, not condensed with other rings, with one nitrogen atom as the only ring hetero atom and three or more double bonds between ring members or between ring members and non-ring members having three double bonds between ring members or between ring members and non-ring members having no bond between the ring nitrogen atom and a non-ring member or having only hydrogen or carbon atoms directly attached to the ring nitrogen atom with hetero atoms or with carbon atoms having three bonds to hetero atoms with at the most one bond to halogen, e.g. ester or nitrile radicals, directly attached to ring carbon atoms
- C07D213/78—Carbon atoms having three bonds to hetero atoms, with at the most one bond to halogen, e.g. ester or nitrile radicals
- C07D213/79—Acids; Esters
- C07D213/803—Processes of preparation
Abstract
The invention relates to the technical field of chemical preparation processes, in particular to a process for preparing carboxylic acid by hydrolyzing a nitrile compound, which comprises the following steps: 1) adding a nitrile compound into a saturated aqueous solution of salt, adding alkali, and carrying out hydrolysis reaction to obtain a reaction solution; 2) adding acid into the reaction liquid obtained in the step 1), filtering to obtain a solid mixture after crystals are completely separated out, and recycling the filtrate; 3) separating the solid mixture obtained in the step 2) to obtain the carboxylic acid. The method adopts saturated aqueous solution of salt as solvent, after nitrile compound is hydrolyzed under alkaline condition, acid is added for acidification, the generated salt is crystallized and separated out, the generated carboxylic acid is solid and is not dissolved in the solvent and is separated out at the same time, then filtration operation is carried out, the generated filtrate is continuously used as solvent for nitrile compound hydrolysis reaction, and the salt and the carboxylic acid are obtained by separating the filtered solid.
Description
Technical Field
The invention relates to the technical field of chemical preparation processes, in particular to a process for preparing carboxylic acid by utilizing nitrile compound hydrolysis.
Background
In the prior art, a nitrile compound is hydrolyzed under an alkaline condition, and then acid is added to adjust pH value to prepare carboxylic acid, a large amount of inorganic salt is generated in the reaction process, the salt content in wastewater generated by hydrolysis of the nitrile compound is increased due to the large amount of inorganic salt, the treatment cost of high-salt wastewater is higher, the efficiency is low, equipment failure is often caused, and the difficulty is increased for treating the process wastewater generated by hydrolysis of the nitrile compound to prepare the carboxylic acid.
Disclosure of Invention
The invention aims to provide a process for preparing carboxylic acid by utilizing nitrile compound hydrolysis.
In order to achieve the purpose, the technical scheme of the invention is as follows:
a process for producing a carboxylic acid by hydrolyzing a nitrile compound, comprising the steps of:
1) adding a nitrile compound into a saturated aqueous solution of salt, adding alkali, and carrying out hydrolysis reaction to obtain a reaction solution;
2) adding acid into the reaction liquid obtained in the step 1), adjusting the pH to 2-3, filtering to obtain a solid mixture after crystals are completely separated out, and recycling the filtrate;
3) adding absolute ethyl alcohol into the solid mixture obtained in the step 2), filtering for the second time, drying the solid obtained by filtering for the second time to obtain salt, distilling the absolute ethyl alcohol from the filtrate obtained by filtering for the second time, concentrating, and drying to obtain carboxylic acid;
the base in step 1) reacts with the acid in step 2) to form the salt in step 1).
Further, the nitrile compound in step 1) is an aliphatic nitrile or an aromatic nitrile.
Further, the molar ratio of the nitrile compound to the base in the step 1) is: 1:2.0 to 2.8.
Further, the temperature of the hydrolysis reaction in the step 1) is 90-95 ℃.
Further, the acid in step 2) is an aqueous solution of hydrogen chloride gas, in this case, the salt in step 1) is sodium chloride and the alkali is sodium hydroxide, or the salt in step 1) is potassium chloride and the alkali is potassium hydroxide, or the salt in step 1) is barium chloride and the alkali is barium hydroxide, or the salt in step 1) is calcium chloride and the alkali is calcium hydroxide.
Further, the acid in step 2) is an aqueous solution of hydrogen bromide gas, and at this time, the salt in step 1) is sodium bromide and the alkali is sodium hydroxide, or the salt in step 1) is potassium bromide and the alkali is potassium hydroxide, or the salt in step 1) is barium bromide and the alkali is barium hydroxide, or the salt in step 1) is calcium chloride and the alkali is calcium hydroxide.
Further, the acid in the step 2) is sulfuric acid, and the mass fraction of the sulfuric acid is 50% -70%.
The process for preparing carboxylic acid by utilizing nitrile compound hydrolysis has the beneficial effects that:
the method adopts a saturated aqueous solution of salt as a solvent, adds acid for acidification after a nitrile compound is hydrolyzed in alkali, and separates out salt crystals and generated carboxylic acid is solid insoluble in the solvent because the solvent is the saturated aqueous solution of salt, and then performs filtration operation, namely the generated salt and the generated carboxylic acid can be separated out, and the generated filtrate is still the saturated aqueous solution of salt and can be continuously used as the solvent for the hydrolysis reaction of the nitrile compound, so that solid salt is generated in the reaction process of preparing the carboxylic acid by hydrolyzing the nitrile compound, the generation amount of salt-containing wastewater is greatly reduced, the process step of treating a large amount of salt-containing wastewater is omitted, and the energy consumption and the wastewater treatment cost are reduced.
Detailed Description
A process for producing a carboxylic acid by hydrolyzing a nitrile compound, comprising the steps of:
1) adding a nitrile compound into a saturated aqueous solution of salt, adding alkali, and carrying out hydrolysis reaction to obtain a reaction solution;
2) adding acid into the reaction liquid obtained in the step 1), adjusting the pH to 2-3, filtering to obtain a solid after crystals are completely separated out, and recycling the filtrate;
3) adding absolute ethyl alcohol into the solid mixture obtained in the step 2), filtering for the second time, drying the solid obtained by filtering for the second time to obtain salt, distilling the absolute ethyl alcohol from the filtrate obtained by filtering for the second time, concentrating, and drying to obtain carboxylic acid;
the base in step 1) reacts with the acid in step 2) to form the salt in step 1).
The nitrile compound in the step 1) is aliphatic nitrile or aromatic nitrile; the molar ratio of the nitrile compound to the base in the step 1) is as follows: 1:2.0 to 2.8; the temperature of the hydrolysis reaction in the step 1) is 90-95 ℃; the acid in the step 2) is an aqueous solution of hydrogen chloride gas, the salt in the step 1) is sodium chloride and the alkali is sodium hydroxide, or the salt in the step 1) is potassium chloride and the alkali is potassium hydroxide, or the salt in the step 1) is barium chloride and the alkali is barium hydroxide, or the salt in the step 1) is calcium chloride and the alkali is calcium hydroxide; the acid in the step 2) is an aqueous solution of hydrogen bromide gas, the salt in the step 1) is sodium bromide and the alkali is sodium hydroxide, or the salt in the step 1) is potassium bromide and the alkali is potassium hydroxide, or the salt in the step 1) is barium bromide and the alkali is barium hydroxide, or the salt in the step 1) is calcium chloride and the alkali is calcium hydroxide; the acid in the step 2) is sulfuric acid, and the mass fraction of the sulfuric acid is 50-70%.
Example 1
The process for preparing carboxylic acid by hydrolysis of nitrile compound of this example comprises the following steps:
1) 0.27mol of 2-chloro-3-cyanopyridine and NaOH0.75mol are added into 300mL of saturated aqueous sodium chloride solution, and the molar ratio of 2-chloro-3-cyanopyridine to NaOH is 1: 2.78; stirring, heating to 90 ℃, preserving heat and carrying out hydrolysis reaction, after reacting for a period of time, sampling for liquid chromatographic analysis, and stopping the reaction when the content of 2-chloro-3-cyanopyridine in chromatographic data is less than or equal to 1% to prepare a reaction solution.
2) Introducing hydrogen chloride gas into the reaction liquid obtained in the step 1), adjusting the pH value to 2-3, reacting for 1h, separating out a large amount of crystals, filtering for one time, recovering the primary filtrate, and using the recovered primary filtrate as a solvent for preparing carboxylic acid by hydrolyzing nitrile compounds, wherein the solid mixture obtained by filtering for one time is generated as 2-chloronicotinic acid solid and sodium chloride solid.
3) Adding absolute ethyl alcohol into the solid mixture obtained in the step 2), stirring, dissolving 2-chloronicotinic acid in the solid mixture, filtering for the second time, washing with a small amount of absolute ethyl alcohol, drying the solid obtained by filtering to obtain sodium chloride, distilling the filtrate obtained by filtering for the second time to obtain ethanol for recycling, concentrating and drying to obtain 2-chloronicotinic acid, wherein the concentration of the sodium chloride in the concentrated solution is 0.05%.
Example 2
The process for preparing carboxylic acid by hydrolysis of nitrile compound of this example comprises the following steps:
1) 0.27mol of 2-chloro-3-cyanopyridine and NaOH0.54mol are added into 300mL of saturated aqueous sodium bromide solution, and the molar ratio of 2-chloro-3-cyanopyridine to NaOH is 1: 2.0; stirring, heating to 92 ℃, preserving heat and carrying out hydrolysis reaction, after reacting for a period of time, sampling for liquid chromatographic analysis, and stopping the reaction when the content of the nitrile compound in chromatographic data is less than or equal to 1 percent to prepare reaction liquid.
2) Introducing hydrogen bromide gas into the reaction solution obtained in the step 1), adjusting the pH value to 2-3, reacting for 1h, separating out a large amount of crystals, filtering for one time, recovering the primary filtrate, and using the recovered primary filtrate as a solvent for preparing carboxylic acid by hydrolyzing a nitrile compound, wherein the solid mixture obtained by filtering for one time is generated as 2-chloronicotinic acid solid and sodium bromide solid.
3) Adding absolute ethyl alcohol into the solid mixture obtained in the step 2), stirring, dissolving 2-chloronicotinic acid in the solid mixture, carrying out secondary filtration, washing with a small amount of absolute ethyl alcohol, drying the solid obtained by the secondary filtration to obtain sodium bromide, distilling the filtrate obtained by the secondary filtration to obtain ethanol for recycling, concentrating and drying to obtain 2-chloronicotinic acid, wherein the concentration of the sodium bromide in the concentrated solution is 0.16%.
Example 3
The process for preparing carboxylic acid by hydrolysis of nitrile compound of this example comprises the following steps:
1) adding 2-chloro-3-cyanopyridine and NaOH0.756 mol in an amount of 0.27mol to 300mL of saturated aqueous sodium sulfate solution, wherein the molar ratio of 2-chloro-3-cyanopyridine to NaOH is 1: 2.8; stirring, heating to 95 ℃, preserving heat and carrying out hydrolysis reaction, after reacting for a period of time, sampling and carrying out liquid chromatography analysis, and stopping the reaction when the content of the 2-chloro-3-cyanopyridine in chromatographic data is less than or equal to 1 percent to prepare a reaction solution.
2) Dropwise adding 70% sulfuric acid into the reaction liquid obtained in the step 1), adjusting the pH value to 2-3, reacting for 1h, separating out a large amount of crystals, filtering for the first time, recovering the primary filtrate, and using the recovered primary filtrate as a solvent for preparing carboxylic acid by hydrolyzing a nitrile compound, wherein the solid mixture obtained by the filtering for the first time is generated as 2-chloronicotinic acid solid and sodium sulfate solid.
3) Adding absolute ethyl alcohol into the solid mixture obtained in the step 2), stirring, dissolving 2-chloronicotinic acid in the solid mixture, carrying out secondary filtration, washing with a small amount of absolute ethyl alcohol, drying the solid obtained by the secondary filtration to obtain sodium sulfate, distilling the filtrate obtained by the secondary filtration to obtain ethanol for recycling, concentrating and drying to obtain 2-chloronicotinic acid, wherein the concentration of salt in the concentrated solution is 0.021%.
Comparative example 1
1) Adding 2-chloro-3-cyanopyridine and 0.75mol of NaOH into 600mL of water, wherein the molar ratio of the 2-chloro-3-cyanopyridine to the NaOH is 1: 2.78; stirring, heating to 90 ℃, preserving heat and carrying out hydrolysis reaction, after reacting for a period of time, sampling and carrying out liquid chromatography analysis, and stopping the reaction when the content of 2-chloro-3-cyanopyridine in chromatographic data is less than or equal to 1 percent to prepare reaction liquid.
2) Dropwise adding 101g of 30% hydrochloric acid into the reaction liquid obtained in the step 1), adjusting the pH value to 2-3, reacting for 1 hour, separating out a large amount of crystals, filtering for one time, recovering the solvent for preparing carboxylic acid by hydrolyzing a nitrile compound from the filtrate for one time, and obtaining the solid obtained by filtering as the generated crude solid 2-chloronicotinic acid.
3) Adding water into the solid obtained in the step 2), stirring, filtering for the second time, washing, drying the solid obtained by filtering for the second time to obtain the 2-chloronicotinic acid with higher purity, recycling the primary filtrate, the secondary filtrate and the washing solution to be used as a solvent for preparing carboxylic acid by hydrolyzing a nitrile compound until sodium chloride in the filtrate is saturated, decompressing and dewatering a saturated sodium chloride solution, using water obtained by concentration as the washing solution, filtering by a plate frame when the water is concentrated to be viscous, wherein the filter residue is a mixture of grey brown viscous sodium chloride and waste residue solid, and the concentration of the sodium chloride in the filtrate is 23%.
Comparative example 2
1) Adding 2-chloro-3-cyanopyridine and 0.75mol of NaOH into 600mL of water, wherein the molar ratio of the 2-chloro-3-cyanopyridine to the NaOH is 1: 2.78; stirring, heating to 90 ℃, preserving heat and carrying out hydrolysis reaction, after reacting for a period of time, sampling and carrying out liquid chromatography analysis, and stopping the reaction when the content of 2-chloro-3-cyanopyridine in chromatographic data is less than or equal to 1 percent to prepare reaction liquid.
2) Adding 148g of 50% sulfuric acid dropwise into the reaction solution obtained in the step 1), adjusting the pH value to 2-3, reacting for 1 hour, separating out a large amount of crystals, filtering for one time, recovering the solvent for preparing carboxylic acid by hydrolyzing nitrile compounds from the filtrate for one time, and obtaining the solid product of the 2-chloronicotinic acid by filtering.
3) Adding water into the solid obtained in the step 2), stirring, filtering for the second time, washing, drying the solid obtained by filtering for the second time to obtain the 2-chloronicotinic acid with higher purity, recycling the primary filtrate, the secondary filtrate and the washing liquid to be used as a solvent for preparing carboxylic acid by hydrolyzing a nitrile compound until sodium sulfate in the filtrate is saturated, decompressing and dewatering a saturated sodium sulfate solution, using water obtained by concentration as the washing liquid, filtering by a plate frame when the water is concentrated to be viscous, wherein the filter residue is a mixture of grey brown viscous sodium chloride and waste residue solid, and the concentration of the sodium sulfate in the filtrate is 29%.
Compared with the comparative example, in the examples 1 to 3 of the present invention, a saturated aqueous solution of salt is used as a solvent, after a nitrile compound is hydrolyzed in alkali, acid is added to perform acidification, the solvent is a saturated aqueous solution of salt, the generated salt is crystallized and precipitated, the generated carboxylic acid is solid and insoluble in the solvent and is simultaneously precipitated, and then the filtration operation is performed, so that the generated salt and the carboxylic acid can be separated, the generated filtrate is still a saturated aqueous solution of salt and can be continuously used as a solvent for the hydrolysis reaction of the nitrile compound, and hydrogen chloride gas or hydrogen bromide gas is added to the step 2) of preparing the carboxylic acid from the nitrile compound to acidify the reaction system, so that no extra water is added to the reaction system, solid salt is generated in the reaction process of preparing the carboxylic acid by hydrolyzing the nitrile compound, the generation amount of salt-containing wastewater is greatly reduced, and the process step of treating a large amount of salt-containing wastewater is omitted, reduce energy consumption and wastewater treatment cost.
Various other modifications and changes may be made by those skilled in the art based on the above-described technical solutions and concepts, and all such modifications and changes should fall within the scope of the claims of the present invention.
Claims (3)
1. A process for producing a carboxylic acid by hydrolyzing a nitrile compound, comprising the steps of:
1) 0.27mol of 2-chloro-3-cyanopyridine and NaOH0.75mol are added into 300mL of saturated aqueous sodium chloride solution, and the molar ratio of 2-chloro-3-cyanopyridine to NaOH is 1: 2.78; stirring, heating to 90 ℃, preserving heat and carrying out hydrolysis reaction, after reacting for a period of time, sampling for liquid chromatographic analysis, and stopping the reaction when the content of 2-chloro-3-cyanopyridine in chromatographic data is less than or equal to 1% to prepare a reaction solution;
2) introducing hydrogen chloride gas into the reaction liquid obtained in the step 1), adjusting the pH value to 2-3, reacting for 1h, separating out a large amount of crystals, filtering for one time, recovering the primary filtrate, and using the recovered primary filtrate as a solvent for preparing carboxylic acid by hydrolyzing a nitrile compound, wherein the solid mixture obtained by filtering for one time is generated as 2-chloronicotinic acid solid and sodium chloride solid;
3) adding absolute ethyl alcohol into the solid mixture obtained in the step 2), stirring, dissolving 2-chloronicotinic acid in the solid mixture, filtering for the second time, washing with a small amount of absolute ethyl alcohol, drying the solid obtained by filtering to obtain sodium chloride, distilling the filtrate obtained by filtering for the second time to obtain ethanol for recycling, concentrating and drying to obtain 2-chloronicotinic acid, wherein the concentration of the sodium chloride in the concentrated solution is 0.05%.
2. A process for producing a carboxylic acid by hydrolyzing a nitrile compound, comprising the steps of:
1) 0.27mol of 2-chloro-3-cyanopyridine and NaOH0.54mol are added into 300mL of saturated aqueous sodium bromide solution, and the molar ratio of 2-chloro-3-cyanopyridine to NaOH is 1: 2.0; stirring, heating to 92 ℃, preserving heat and carrying out hydrolysis reaction, after reacting for a period of time, sampling for liquid chromatographic analysis, and stopping the reaction when the content of the nitrile compound in chromatographic data is less than or equal to 1% to prepare a reaction solution;
2) introducing hydrogen bromide gas into the reaction solution obtained in the step 1), adjusting the pH value to 2-3, reacting for 1h, separating out a large amount of crystals, filtering for one time, recovering the primary filtrate, and using the recovered primary filtrate as a solvent for preparing carboxylic acid by hydrolyzing a nitrile compound, wherein the solid mixture obtained by filtering for one time is generated as 2-chloronicotinic acid solid and sodium bromide solid;
3) adding absolute ethyl alcohol into the solid mixture obtained in the step 2), stirring, dissolving 2-chloronicotinic acid in the solid mixture, carrying out secondary filtration, washing with a small amount of absolute ethyl alcohol, drying the solid obtained by the secondary filtration to obtain sodium bromide, distilling the filtrate obtained by the secondary filtration to obtain ethanol for recycling, concentrating and drying to obtain 2-chloronicotinic acid, wherein the concentration of the sodium bromide in the concentrated solution is 0.16%.
3. A process for producing a carboxylic acid by hydrolyzing a nitrile compound, comprising the steps of:
1) adding 2-chloro-3-cyanopyridine and NaOH0.756 mol in an amount of 0.27mol to 300mL of saturated aqueous sodium sulfate solution, wherein the molar ratio of 2-chloro-3-cyanopyridine to NaOH is 1: 2.8; stirring, heating to 95 ℃, preserving heat and carrying out hydrolysis reaction, after reacting for a period of time, sampling for liquid chromatographic analysis, and stopping the reaction when the content of 2-chloro-3-cyanopyridine in chromatographic data is less than or equal to 1% to prepare a reaction solution;
2) dropwise adding 70% sulfuric acid into the reaction liquid obtained in the step 1), adjusting the pH value to 2-3, reacting for 1h, separating out a large amount of crystals, filtering for the first time, recovering the primary filtrate, and continuously using the recovered primary filtrate as a solvent for preparing carboxylic acid by hydrolyzing a nitrile compound, wherein the solid mixture obtained by filtering for the first time is generated as 2-chloronicotinic acid solid and sodium sulfate solid;
3) adding absolute ethyl alcohol into the solid mixture obtained in the step 2), stirring, dissolving 2-chloronicotinic acid in the solid mixture, carrying out secondary filtration, washing with a small amount of absolute ethyl alcohol, drying the solid obtained by the secondary filtration to obtain sodium sulfate, distilling the filtrate obtained by the secondary filtration to obtain ethanol for recycling, concentrating and drying to obtain 2-chloronicotinic acid, wherein the concentration of salt in the concentrated solution is 0.021%.
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| JPS59144759A (en) * | 1983-02-07 | 1984-08-18 | Yuki Gosei Yakuhin Kogyo Kk | Preparation of 2-chloronicotinic acid |
| CN102093149A (en) * | 2010-12-08 | 2011-06-15 | 天津理工大学 | Method for preparing carboxylic acid compound by promoting rapid hydrolysis of cyan |
| CN104592104B (en) * | 2015-01-13 | 2017-02-22 | 江苏中邦制药有限公司 | Method for preparing 2-chloronicotinic acid |
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