CN113788755A - Preparation method of 2-methyl dimethyl glutarate - Google Patents
Preparation method of 2-methyl dimethyl glutarate Download PDFInfo
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- CN113788755A CN113788755A CN202111125876.5A CN202111125876A CN113788755A CN 113788755 A CN113788755 A CN 113788755A CN 202111125876 A CN202111125876 A CN 202111125876A CN 113788755 A CN113788755 A CN 113788755A
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- sulfuric acid
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- concentrated sulfuric
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- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C67/00—Preparation of carboxylic acid esters
- C07C67/18—Preparation of carboxylic acid esters by conversion of a group containing nitrogen into an ester group
- C07C67/22—Preparation of carboxylic acid esters by conversion of a group containing nitrogen into an ester group from nitriles
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Abstract
The invention relates to the technical field of chemical production, in particular to a preparation method of 2-methyl dimethyl glutarate, which comprises the following steps: adding concentrated sulfuric acid to a mixture of 2-methylglutaronitrile and methanol, and reacting the concentrated sulfuric acid with the 2-methylglutaronitrile and the methanol. The process method for synthesizing the 2-methyl dimethyl glutarate by the one-step reaction of the 2-methyl glutaronitrile has less reaction steps and high yield.
Description
Technical Field
The invention relates to the technical field of chemical production, in particular to a preparation method of 2-methyl dimethyl glutarate.
Background
The main by-product of the butadiene cyanohydrogenation route to adiponitrile is 2-methylglutaronitrile. The development and gradual industrialization of the process for synthesizing adiponitrile by using the domestic butadiene route can generate 2-methylglutaronitrile with a certain scale yield. Data inquiry shows that the development of the technology related to the downstream application of methylglutaronitrile is lacked, so that the development of the by-product downstream application is needed.
The 2-methyl dimethyl glutarate is an environment-friendly organic solvent and can be widely applied to the fields of coatings, hardware, electronics and the like. 2-methylglutaronitrile can be used for synthesizing 2-methylglutaric acid dimethyl ester, but the synthesis method in the prior art needs multiple steps to complete, and has the disadvantages of complex process, large equipment investment and low production efficiency.
Disclosure of Invention
In order to overcome the technical problems, the invention provides a preparation method of 2-methyl dimethyl glutarate.
In order to achieve the above purpose, the technical scheme of the invention is as follows:
the preparation method of the dimethyl 2-methylglutarate comprises the following steps:
adding concentrated sulfuric acid to a mixture of 2-methylglutaronitrile and methanol, and reacting the concentrated sulfuric acid with the 2-methylglutaronitrile and the methanol.
In some preferred embodiments, the preparation method further comprises:
separating by a separation method to obtain the product of the dimethyl 2-methylglutarate.
In some preferred embodiments, the step of adding concentrated sulfuric acid is adding concentrated sulfuric acid at constant pressure and constant speed.
In some preferred embodiments, the step of adding concentrated sulfuric acid is to add concentrated sulfuric acid at constant pressure and constant speed without heating, to react by using the reaction heat of concentrated sulfuric acid, to control the reaction temperature below 100 ℃, and to inject concentrated sulfuric acid after 2-10 min.
In some preferred embodiments, the reaction of the concentrated sulfuric acid with the 2-methylglutaronitrile and the methanol is carried out at a temperature of 80 to 190 ℃.
In some preferred embodiments, the reaction is carried out under reflux with stirring.
In some preferred embodiments, the concentrated sulfuric acid is 76-80% concentrated sulfuric acid.
In some preferred embodiments, the reaction raw materials comprise, by weight: 150 portions of 2-methylglutaronitrile 100, 400 portions of methanol 350 and 180 portions of concentrated sulfuric acid 130.
In some preferred embodiments, the reaction time is from 30min to 5 h.
In some preferred embodiments, the separation method comprises: washing the reaction solution with water to remove soluble impurities to obtain the 2-methyl dimethyl glutarate product.
The invention has the advantages that:
the process method for synthesizing the 2-methyl dimethyl glutarate by the one-step reaction of the 2-methyl glutaronitrile has less reaction steps and high yield.
Detailed Description
Detailed description of the preferred embodiments
The preparation method of the dimethyl 2-methylglutarate comprises the following steps:
adding concentrated sulfuric acid to a mixture of 2-methylglutaronitrile and methanol, and reacting the concentrated sulfuric acid with the 2-methylglutaronitrile and the methanol.
Equation of reaction
MGN + 2H2O + H2SO4 +CH3OH→（NH4）2SO4 + CH3OOCH（CH3）CH2CH2COOCH3
In the formula: MGN: 2-methylglutaronitrile.
After the reaction is finished, the reaction yield of the 2-methyl dimethyl glutarate is over 90 percent through testing, and the yield testing method is chromatography. Concentrated sulfuric acid contains less water, so that the consumption of the hydrolysis reaction is met by controlling the concentrated sulfuric acid, and the reaction equation is favorably carried out rightwards. The 2-methyl dimethyl glutarate with high yield can be prepared in one step by the reaction without adding a catalyst and removing a byproduct ammonium sulfate, and the process is simple, less in equipment investment and high in production efficiency.
Further, in the above reaction, the concentrated sulfuric acid is 76% to 80% concentrated sulfuric acid, further, the concentrated sulfuric acid is 75% concentrated sulfuric acid, and the concentration of the concentrated sulfuric acid is controlled within the concentration range, which is more beneficial to improving the reaction efficiency.
The preparation method also comprises the following steps:
separating by a separation method to obtain the product of the dimethyl 2-methylglutarate.
Specifically, the separation method may be to wash the reaction solution with water to remove soluble impurities, such as unreacted methanol and sulfuric acid, and by-product ammonium sulfate, etc., to obtain dimethyl 2-methylglutarate product. The separation method can be used for separating the 2-methyl dimethyl glutarate only by using water, and is simple and convenient to operate. The water washing separation method can be used for a plurality of times in a small amount. The water washing can be carried out for one time, and the cost is low. Of course, other separation methods, such as distillation, can also be used.
In the method, the step of adding the concentrated sulfuric acid is to add the concentrated sulfuric acid at constant pressure and constant speed without heating, for example, the concentrated sulfuric acid is put into a constant-pressure device, such as a constant-pressure funnel, an elevated tank and the like, the reaction is carried out by utilizing the reaction heat of the concentrated sulfuric acid, the reaction temperature is controlled below 100 ℃ by controlling the dropping speed of the concentrated sulfuric acid, the overhigh temperature and the carbonization and carbon deposition of organic matters in the system are prevented, and the high efficiency and the safety of the initial reaction are ensured.
Then, the concentrated sulfuric acid can be continuously added at constant pressure and constant speed, and the reaction temperature is carried out at the temperature of 80-190 ℃ until the reaction is finished. Or adding the concentrated sulfuric acid at constant pressure and constant speed for 2-10min, and injecting the residual concentrated sulfuric acid until the reaction is finished. Therefore, the concentration of the concentrated sulfuric acid for starting the initial reaction is provided at the initial stage, the reaction rate is accelerated at the later stage, the production period is shortened, and the production cost is reduced.
The reaction pressure is not particularly limited, and may be normal pressure or positive pressure.
The total reaction time of the two methods is 30min-5 h. The product is detected by chromatographic analysis, the reaction is controlled in the time period, the yield is high, the cost is relatively low, and the comprehensive production benefit is good.
In the method, the reaction is carried out in a reflux stirring state, the mass transfer and heat transfer are carried out in a stirring manner, so that the reaction is more balanced, and the methanol can be better utilized in a reflux manner, particularly in a condensation reflux manner.
In the above process, the ratio of 2-methylglutaronitrile, methanol and concentrated sulfuric acid can be determined by those skilled in the art according to the amount of 2-methylglutaronitrile contained in the starting materials and the reaction time planned to proceed, the reaction starting materials being in parts by weight: 150 portions of 2-methylglutaronitrile 100, 400 portions of methanol 350 and 180 portions of concentrated sulfuric acid 130. Before the method of the present invention, 2-methylglutaronitrile and methanol may be mixed well.
The present invention is further illustrated by, but is not limited to, the following examples. In the examples, the yields are based on methylglutaronitrile calculation, yield = moles of dimethyl methylglutarate/moles of methylglutaronitrile.
The main test tools are: 500ml of three-mouth reaction bottle, an air-cooled reflux glass tube, a thermometer at 0-200 ℃, a constant-pressure dropping funnel, a heating sleeve, a balance, a gas chromatograph and the like.
Raw materials: 2-methylglutaronitrile (national group of drugs)
Sulfuric acid 75% reagent grade
Methanol: reagent grade
Example 1:
108g of 2-methylglutaronitrile and 364g of methanol were introduced into the reaction flask. 142g of 75% sulfuric acid is poured into a constant-pressure dropping funnel and is installed and connected to the upper surface of a reaction bottle, a reaction condensation reflux pipe is inserted into the opening of the reaction bottle, and a thermometer is installed; the initial reaction is not heated, sulfuric acid is dripped into a reaction bottle, the reaction heat is utilized and is controlled to be not higher than 100 ℃, the whole process is stirred, the temperature is evaporated, refluxed and radiated by methanol, and after 2 hours, the temperature is reduced, and sampling detection is carried out, so that the yield of the product, namely the dimethyl 2-methylglutarate is 90%. And washing the reaction solution with water to remove ammonium sulfate, methanol and sulfuric acid to obtain a crude product.
Example 2:
the method comprises the following operation steps: 108g of 2-methylglutaronitrile and 364g of methanol were introduced into the reaction flask. 152g of 75% sulfuric acid is poured into a constant-pressure dropping funnel and is installed and connected to the upper surface of a reaction bottle, a reaction condensation reflux pipe is inserted into the opening of the reaction bottle, and a thermometer is installed; the initial reaction is not heated, sulfuric acid is dripped into a reaction bottle, the whole process is stirred, the temperature is evaporated by methanol, the reflux and the heat dissipation are carried out, after 3 hours, the temperature is reduced, and the sample is taken for chromatographic detection, so that the yield of the product, namely the dimethyl 2-methylglutarate, is 93 percent. And washing the reaction solution with water to remove ammonium sulfate, methanol and sulfuric acid to obtain a crude product.
Example 3:
108g of 2-methylglutaronitrile and 364g of methanol were introduced into the reaction flask. Pouring 145 g of 75% sulfuric acid into a constant-pressure dropping funnel, installing and connecting the dropping funnel to the upper surface of a reaction bottle, inserting a reaction condensation reflux pipe into the opening of the reaction bottle, and installing a thermometer; the initial reaction is not heated, sulfuric acid is dripped into a reaction bottle, after 2 minutes, the residual sulfuric acid is completely injected into the reaction bottle, the whole process is stirred, the temperature is evaporated by methanol, the reflux and the heat dissipation are carried out, after 2 hours, the temperature is reduced, the sampling detection is carried out, and the yield of the product 2-methyl dimethyl glutarate is 92%. And washing the reaction solution with water to remove ammonium sulfate, methanol and sulfuric acid to obtain a crude product.
Example 4
108g of 2-methylglutaronitrile and 364g of methanol were introduced into the reaction flask. Pouring 163g of 78% sulfuric acid into a constant-pressure dropping funnel, installing and connecting the sulfuric acid to the upper surface of a reaction bottle, inserting a reaction condensation reflux pipe into the opening of the reaction bottle, and installing a thermometer; the initial reaction is not heated, sulfuric acid is dripped into a reaction bottle, after 2 minutes, the residual sulfuric acid is completely injected into the reaction bottle, the whole process is stirred, the temperature is evaporated by methanol, the reflux and the heat dissipation are carried out, after 2 hours, the temperature is reduced, the sampling detection is carried out, and the yield of the product 2-methyl dimethyl glutarate is 89%. And washing the reaction solution with water to remove ammonium sulfate, methanol and sulfuric acid to obtain a crude product.
Example 5
108g of 2-methylglutaronitrile and 364g of methanol were introduced into the reaction flask. 170g of 78% sulfuric acid is poured into a constant-pressure dropping funnel and is installed and connected to the upper surface of a reaction bottle, a reaction condensation reflux pipe is inserted into the opening of the reaction bottle, and a thermometer is installed; the initial reaction is not heated, sulfuric acid is dripped into a reaction bottle, after 2 minutes, the residual sulfuric acid is completely injected into the reaction bottle, the whole process is stirred, the temperature is evaporated by methanol, the reflux and the heat dissipation are carried out, after 2 hours, the temperature is reduced, the sampling detection is carried out, and the yield of the product 2-methyl dimethyl glutarate is 89%. And washing the reaction solution with water to remove ammonium sulfate, methanol and sulfuric acid to obtain a crude product.
The above description is only for the preferred embodiment and examples of the present invention, but the scope of the present invention is not limited thereto, and any person skilled in the art can substitute or change the technical solution of the present invention and its inventive concept within the technical scope of the present invention.
Claims (10)
- A method for preparing dimethyl 1.2-methylglutarate, which is characterized in that the method comprises the following steps:adding concentrated sulfuric acid to a mixture of 2-methylglutaronitrile and methanol, and reacting the concentrated sulfuric acid with the 2-methylglutaronitrile and the methanol.
- 2. The method of claim 1, further comprising: separating by a separation method to obtain the product of the dimethyl 2-methylglutarate.
- 3. The method of claim 1, wherein the step of adding concentrated sulfuric acid is a constant pressure and constant velocity addition of concentrated sulfuric acid.
- 4. The method for preparing dimethyl 2-methylglutarate according to claim 1 wherein the step of adding concentrated sulfuric acid is that concentrated sulfuric acid is added at constant pressure and speed without heating, the reaction is carried out by utilizing the reaction heat of concentrated sulfuric acid, the reaction temperature is controlled below 100 ℃, and the concentrated sulfuric acid is injected after 2-10 min.
- 5. The method of claim 1, wherein the reaction of concentrated sulfuric acid with the 2-methylglutaronitrile and methanol is carried out at a temperature of 80-190 ℃.
- 6. The method of claim 1, wherein the reaction is carried out under reflux with stirring.
- 7. The method of claim 1, wherein the concentrated sulfuric acid is 76-80% concentrated sulfuric acid.
- 8. The process for preparing dimethyl 2-methylglutarate according to claim 1, characterized in that the reaction raw materials are in parts by weight: 150 portions of 2-methylglutaronitrile 100, 400 portions of methanol 350 and 180 portions of concentrated sulfuric acid 130.
- 9. The process for the preparation of dimethylmethylglutarate according to claim 12, characterised in that the reaction time is comprised between 30min and 5 h.
- 10. The method of claim 2, wherein the separation method comprises: washing the reaction solution with water to remove soluble impurities to obtain the 2-methyl dimethyl glutarate product.
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Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN101395123A (en) * | 2006-03-07 | 2009-03-25 | 罗地亚运作公司 | Rhodia operations |
| CN101641318A (en) * | 2006-11-24 | 2010-02-03 | 罗地亚运作公司 | Method for converting nitrile compounds into corresponding carboxylic acids and esters |
| US20100249449A1 (en) * | 2007-10-18 | 2010-09-30 | Evonik Roehm Gmbh | Method for amidating of nitrile in the presence of sulfuric acid |
| US20100279911A1 (en) * | 2007-05-07 | 2010-11-04 | Rhodia Operations | Anti-graffiti treatment |
| CN109824514A (en) * | 2019-03-06 | 2019-05-31 | 重庆中平紫光科技发展有限公司 | A method of synthesis 2- methylglutaric acid dimethyl ester |
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- 2021-09-26 CN CN202111125876.5A patent/CN113788755A/en active Pending
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101395123A (en) * | 2006-03-07 | 2009-03-25 | 罗地亚运作公司 | Rhodia operations |
| CN101641318A (en) * | 2006-11-24 | 2010-02-03 | 罗地亚运作公司 | Method for converting nitrile compounds into corresponding carboxylic acids and esters |
| US20100279911A1 (en) * | 2007-05-07 | 2010-11-04 | Rhodia Operations | Anti-graffiti treatment |
| US20100249449A1 (en) * | 2007-10-18 | 2010-09-30 | Evonik Roehm Gmbh | Method for amidating of nitrile in the presence of sulfuric acid |
| CN109824514A (en) * | 2019-03-06 | 2019-05-31 | 重庆中平紫光科技发展有限公司 | A method of synthesis 2- methylglutaric acid dimethyl ester |
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