CN109320412A - A kind of preparation method of 2,4,6- trimethylbenzoic acid - Google Patents
A kind of preparation method of 2,4,6- trimethylbenzoic acid Download PDFInfo
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- CN109320412A CN109320412A CN201811473780.6A CN201811473780A CN109320412A CN 109320412 A CN109320412 A CN 109320412A CN 201811473780 A CN201811473780 A CN 201811473780A CN 109320412 A CN109320412 A CN 109320412A
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- trimethylbenzoic
- mesitylene
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- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C51/00—Preparation of carboxylic acids or their salts, halides or anhydrides
- C07C51/15—Preparation of carboxylic acids or their salts, halides or anhydrides by reaction of organic compounds with carbon dioxide, e.g. Kolbe-Schmitt synthesis
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- B01J27/00—Catalysts comprising the elements or compounds of halogens, sulfur, selenium, tellurium, phosphorus or nitrogen; Catalysts comprising carbon compounds
- B01J27/06—Halogens; Compounds thereof
- B01J27/08—Halides
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- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C51/00—Preparation of carboxylic acids or their salts, halides or anhydrides
- C07C51/42—Separation; Purification; Stabilisation; Use of additives
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- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C51/00—Preparation of carboxylic acids or their salts, halides or anhydrides
- C07C51/42—Separation; Purification; Stabilisation; Use of additives
- C07C51/47—Separation; Purification; Stabilisation; Use of additives by solid-liquid treatment; by chemisorption
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- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C51/00—Preparation of carboxylic acids or their salts, halides or anhydrides
- C07C51/42—Separation; Purification; Stabilisation; Use of additives
- C07C51/48—Separation; Purification; Stabilisation; Use of additives by liquid-liquid treatment
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Abstract
The present invention provides a kind of preparation methods of 2,4,6- trimethylbenzoic acids, comprising the following steps: reacts mesitylene and carbon dioxide under the action of catalyst, obtains 2,4,6- trimethylbenzoic acids；The catalyst is hydrogen chloride or concentrated hydrochloric acid.Preparation method provided by the invention replaces anhydrous aluminum chloride in the prior art using hydrogen chloride or concentrated hydrochloric acid, avoid the problem of being needed in reaction process using a large amount of anhydrous aluminum chlorides, and method provided by the invention be prepared 2,4,6- trimethylbenzoic acid purity is higher, up to 98.1%~99.1%.In addition, preparation method provided by the invention can successive reaction, be suitble to industrial mass production.
Description
Technical field
The present invention relates to the preparation methods of chemical products, more particularly to a kind of preparation side of 2,4,6- trimethylbenzoic acids
Method.
Background technique
2,4,6 trimethylbenzoic acids are a kind of important organic synthesis intermediates, are widely used in producing dyestuff, desinsection
Agent, medicine and photoinitiator intermediate.In recent years, as its application field is continuously increased, the city of 2,4,6 trimethylbenzoic acids
Field potentiality are also increasing, and preparation of industrialization is got more and more extensive concerning of people.
At present synthesis 2,4,6- trimethylbenzoic acids method be mainly the direct carboxylation method of mesitylene carbon dioxide, i.e., with
Anhydrous aluminum chloride is catalyst, is catalyzed the method that mesitylene and carbon dioxide synthesize 2,4,6- trimethylbenzoic acids.But by
In above-mentioned reaction process, 2 for needing using a large amount of anhydrous aluminum chloride, and being prepared, 4,6- trimethylbenzoic acid purity
Lower, about 92-96% is unable to satisfy people's demand.
Summary of the invention
The present invention provides a kind of preparation methods of 2,4,6- trimethylbenzoic acids, and preparation method provided by the invention is with chlorine
Changing hydrogen or concentrated hydrochloric acid is catalyst, when avoiding in the prior art using anhydrous aluminum chloride as catalyst, is needed using a large amount of anhydrous
The problem of aluminium chloride, and 2,4, the 6- trimethylbenzoic acid purity that method provided by the invention obtains are higher, up to 98.1%
~99.1%.
This application provides a kind of preparation methods of 2,4,6- trimethylbenzoic acids, comprising the following steps:
Mesitylene and carbon dioxide are reacted under the action of catalyst, obtain 2,4,6- trimethylbenzoic acids；Institute
Stating catalyst is hydrogen chloride or concentrated hydrochloric acid.
Preferably, the mass concentration of the concentrated hydrochloric acid is 37%~40%.
Preferably, the quality of the catalyst is the 0.1%~20% of mesitylene quality.
Preferably, the molar ratio of the mesitylene and carbon dioxide is 1:0.3~0.5.
Preferably, it is reacted by the way of being continuously injected into mesitylene and carbon dioxide to reactor；Described equal three
The flow that is continuously injected into of toluene is 50~100mL/min.
Preferably, the temperature of the reaction is 20~70 DEG C；The pressure of the reaction is 2~4MPa.
Preferably, the time of the reaction is 5~25s.
Preferably, after the reaction further include post-processing to reaction product；
When the catalyst is hydrogen chloride, the post-processing are as follows: the reaction product is cooled down and is separated by solid-liquid separation,
Obtain 2,4,6- trimethylbenzoic acid；
When the catalyst is concentrated hydrochloric acid, the post-processing are as follows: be successively layered the reaction product, organic layer
Cooling and separation of solid and liquid, obtains 2,4,6- trimethylbenzoic acids.
The present invention provides a kind of preparation methods of 2,4,6- trimethylbenzoic acids, comprising the following steps: by mesitylene
It is reacted under the action of catalyst with carbon dioxide, obtains 2,4,6- trimethylbenzoic acids；The catalyst be hydrogen chloride or
Concentrated hydrochloric acid.In preparation method provided by the invention, mesitylene and carbon dioxide are under hydrogen chloride or concentrated hydrochloric acid catalyst action
It reacts, generates 2,4,6- trimethylbenzoic acid.Preparation method provided by the invention is replaced existing using hydrogen chloride or concentrated hydrochloric acid
There is the anhydrous aluminum chloride in technology, avoids the problem of being needed in reaction process using a large amount of anhydrous aluminum chlorides, and the present invention
2,4, the 6- trimethylbenzoic acid purity that the method for offer is prepared are higher, up to 98.1%~99.1%.In addition, of the invention
The preparation method of offer can successive reaction, be suitble to industrial mass production.
Detailed description of the invention
Fig. 1 is the nuclear magnetic spectrogram for the 2,4,6- trimethylbenzoic acid that the embodiment of the present invention 1 is prepared；
Fig. 2 is the mass spectrogram for the 2,4,6- trimethylbenzoic acid that the embodiment of the present invention 1 is prepared.
Specific embodiment
The present invention provides a kind of preparation methods of 2,4,6- trimethylbenzoic acids, comprising the following steps:
Mesitylene and carbon dioxide are reacted under the action of catalyst, obtain 2,4,6- trimethylbenzoic acids；Institute
Stating catalyst is hydrogen chloride or concentrated hydrochloric acid.
In the present invention, unless otherwise specified, all raw materials are commercial goods.
The present invention reacts mesitylene and carbon dioxide under the action of catalyst, obtains 2,4,6- trimethylbenzene first
Acid.
In the present invention, the carbon dioxide is preferably liquid carbon dioxide.In the present invention, the catalyst is chlorination
Hydrogen or concentrated hydrochloric acid；When the catalyst is concentrated hydrochloric acid, the mass concentration of the concentrated hydrochloric acid is preferably 37%~40%, further
Preferably 38%~39%.The quality of the catalyst is the 0.1%~20% of mesitylene quality, further preferably 5%
~10%.
In the present invention, the pressure of the reaction is preferably 2~4MPa, further preferably 2.5~3.5MPa, more preferably
For 3.0~3.5MPa.The present invention preferably controls the pressure of reaction by the flow of mesitylene and carbon dioxide.The present invention is excellent
Reaction pressure control within the above range, is conducive to reaction and gone on smoothly, generate 2,4,6- trimethylbenzoic acid by choosing.
In the present invention, the molar ratio of the mesitylene and carbon dioxide is preferably 1:0.3~0.5, further preferably
For 1:0.35~0.45.Present invention preferably employs the modes for being continuously injected into mesitylene and carbon dioxide to be reacted, so that instead
It should be able to be carried out continuously；The flow that is continuously injected into of the mesitylene is preferably 50~100mL/min, further preferably 60~
90mL/min, more preferably 70~80mL/min.Mesitylene is preferably continuously injected into flow control in above-mentioned model by the present invention
In enclosing, is conducive to the pressure that will be reacted control in OK range, is conducive to reaction and generates 2,4,6- trimethylbenzoic acids.
In the present invention, the mesitylene and carbon dioxide are preferably continuously injected into reactor simultaneously.The present invention preferably adopts
Reacted in fashion described above, be conducive to make preparation method provided by the invention can successive reaction, be suitble to industrial mass production.
In the present invention, the temperature of the reaction is preferably 20~70 DEG C, and further preferably 30~60 DEG C, more preferably
40~50 DEG C.The present invention preferably controls reaction temperature within the above range, is on the one hand conducive to make mesitylene and titanium dioxide
Carbon reaction generates 2,4,6- trimethylbenzoic acid；On the other hand be conducive to the product 2,4,6- trimethylbenzoic acid for generating reaction
It is dissolved completely in mesitylene, convenient for transferring out reaction product from reaction unit.
In the present invention, the time of the reaction is preferably 5~25s, further preferably 10~20s, and more preferably 15
~20s.In the present invention, when being reacted by the way of being continuously injected into mesitylene and carbon dioxide, the reaction
In terms of time starts by mesitylene and carbon dioxide injection；The present invention preferably passes through coil lengths control reaction in reaction unit
Time.In the present invention, the reaction unit is preferably microreactor；The present invention is not special to the source of the microreactor
It is required that using well-known to those skilled in the art.
In the present invention, the reaction is preferably indicated with Formulas I:
After completing reaction, the present invention preferably post-processes reaction product, obtains 2,4,6- trimethylbenzoic acids.
When the catalyst is hydrogen chloride, the reaction product is preferably cooled down and is separated by solid-liquid separation by the present invention, is obtained
To 2,4,6- trimethylbenzoic acid.In the present invention, the temperature of the cooling is preferably 0~5 DEG C.The present invention preferably passes through cooling
Processing, is precipitated 2,4,6- trimethylbenzoic acids from reaction system.The present invention is not special to cooling specific embodiment
Limitation, using the type of cooling well-known to those skilled in the art.The present invention preferably carries out reaction product after cooling
It is separated by solid-liquid separation, collects solid, obtain 2,4,6- trimethylbenzoic acids.In the present invention, the separation of solid and liquid preferably includes successively
The centrifugation and filtering of progress.The specific embodiment of centrifugation and filtering is not particularly limited in the present invention, using art technology
Centrifugation known to personnel and filter type.In the present invention, the filtrate being obtained by filtration is preferably mesitylene, this
The filtrate being obtained by filtration preferably is transmitted back to reaction unit by invention, is recycled, and the filter cake being obtained by filtration, as 2 are collected,
4,6- trimethylbenzoic acid.
When the catalyst is concentrated hydrochloric acid, the reaction product is preferably successively layered by the present invention, organic layer is cold
But and solid-liquid separation treatment, 2,4,6- trimethylbenzoic acids are obtained.In the present invention, the reaction product can be automatically separated into two
Layer, upper layer are organic layer, and lower layer is salt acid layer.Salt acid layer is preferably re-started recycling by the present invention.
After layering, organic layer is preferably successively carried out organic layer cooling and solid-liquid separation treatment by the present invention, obtains 2,4,6-
Trimethylbenzoic acid.In the present invention, the cooling temperature of the organic layer is preferably 0~5 DEG C.The present invention preferably passes through cooling place
Reason, is precipitated 2,4,6- trimethylbenzoic acids from organic layer, obtains mixture.The present invention does not have cooling specific embodiment
There is special limitation, using the type of cooling well-known to those skilled in the art.The present invention is preferably by cooling obtained mixing
Object is separated by solid-liquid separation, and is collected solid, is obtained 2,4,6- trimethylbenzoic acids.In the present invention, the preferred packet of the separation of solid and liquid
Include the centrifugation and filtering successively carried out.The specific embodiment of centrifugation and filtering is not particularly limited in the present invention, using ability
Centrifugation known to field technique personnel and filter type.In the present invention, the filtrate being obtained by filtration is preferably equal three
The filtrate being obtained by filtration preferably is transmitted back to reaction unit, is recycled by toluene, the present invention, collects the filter being obtained by filtration
Cake, as 2,4,6- trimethylbenzoic acids.
Below in conjunction with the embodiment in the present invention, the technical solution in the present invention is clearly and completely described.
Embodiment 1
Each reaction raw materials are added in material pot, control mesitylene flow is 50mL/min, and temperature is 70 in microreactor
DEG C, pressure 3.0MPa, mesitylene and carbon dioxide molar ratio 1:0.5, catalyst are the concentrated hydrochloric acid of mass concentration 38%, benefit
Be 25s with the coil lengths control reaction time, be layered after reaction, the recycling of lower layer's concentrated hydrochloric acid, upper layer through cooling centrifugal filtration,
It collects solid and obtains 2,4,6- trimethylbenzoic acids, filtered filtrate is transmitted back to material pot, and the reaction was continued, product purity
99.1%.
2 that embodiment 1 is prepared, 4,6- trimethylbenzoic acids carry out nmr analysis and mass spectral analysis, analyze result
As depicted in figs. 1 and 2, wherein Fig. 1 be 2,4,6- trimethylbenzoic acids nuclear magnetic spectrogram, Fig. 22,4,6- trimethylbenzoic acid
Mass spectrogram.By Fig. 1 and Fig. 2 it is found that the product that the present invention is prepared is 2,4,6- trimethylbenzoic acids.
Embodiment 2
Each reaction raw materials are added in material pot, control mesitylene flow is 100mL/min, and temperature is 40 in microreactor
DEG C, pressure 3.5MPa, mesitylene and carbon dioxide molar ratio 1:0.3, catalyst is hydrogen chloride gas, utilizes coil lengths
The control reaction time is 25s, after reaction through cooling centrifugal filtration, collects solid and obtains 2,4,6- trimethylbenzoic acids, mistake
Filtrate after filter is transmitted back to material pot, and the reaction was continued, product purity 99.0%.
Embodiment 3
Each reaction raw materials are added in material pot, control mesitylene flow is 100mL/min, and temperature is 70 in microreactor
DEG C, pressure 2.0MPa, mesitylene and carbon dioxide molar ratio 1:0.3, catalyst are the concentrated hydrochloric acid of mass concentration 40%, benefit
Residence time with coil lengths control reaction is 20s, is layered after reaction, the recycling of lower layer's concentrated hydrochloric acid, upper layer through it is cooling from
Heart filtering collects solid and obtains 2,4,6- trimethylbenzoic acids, and filtered filtrate is transmitted back to material pot, and the reaction was continued, and product is pure
Degree 98.1%.
The nuclear magnetic spectrogram and mass spectrogram of the 2,4,6- trimethylbenzoic acid that embodiment 2 and embodiment 3 are prepared and implementation
Fig. 1 that the test of example 1 obtains is consistent with Fig. 2, and details are not described herein.
To sum up, 2,4,6- trimethylbenzoic acids of purity is high can be prepared in method provided by the invention, and purity is reachable
98.1~99.1%.
The above is only a preferred embodiment of the present invention, it is noted that for the ordinary skill people of the art
For member, various improvements and modifications may be made without departing from the principle of the present invention, these improvements and modifications are also answered
It is considered as protection scope of the present invention.
Claims (8)
1. one kind 2,4, the preparation method of 6- trimethylbenzoic acid, comprising the following steps:
Mesitylene and carbon dioxide are reacted under the action of catalyst, obtain 2,4,6- trimethylbenzoic acids；It is described to urge
Agent is hydrogen chloride or concentrated hydrochloric acid.
2. preparation method according to claim 1, which is characterized in that the mass concentration of the concentrated hydrochloric acid be 37%~
40%.
3. preparation method according to claim 1 or 2, which is characterized in that the quality of the catalyst is mesitylene matter
The 0.1%~20% of amount.
4. preparation method according to claim 1, which is characterized in that the molar ratio of the mesitylene and carbon dioxide is
1:0.3~0.5.
5. preparation method according to claim 1 or 4, which is characterized in that be continuously injected into mesitylene using to reactor
It is reacted with the mode of carbon dioxide；The flow that is continuously injected into of the mesitylene is 50~100mL/min.
6. preparation method according to claim 1, which is characterized in that the temperature of the reaction is 20~70 DEG C；It is described anti-
The pressure answered is 2~4MPa.
7. preparation method according to claim 1 or 6, which is characterized in that the time of the reaction is 5~25s.
8. preparation method according to claim 1, which is characterized in that further include the rear place to reaction product after the reaction
Reason；
When the catalyst is hydrogen chloride, the post-processing are as follows: the reaction product is cooled down and is separated by solid-liquid separation, is obtained
2,4,6- trimethylbenzoic acid；
When the catalyst is concentrated hydrochloric acid, the post-processing are as follows: be successively layered the reaction product, organic layer cooling
And separation of solid and liquid, obtain 2,4,6- trimethylbenzoic acids.
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113698287A (en) * | 2021-08-27 | 2021-11-26 | 中国石油化工股份有限公司 | Method for preparing p-methylbenzoic acid by catalyzing carbon dioxide and methylbenzene |
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| GB2350837A (en) * | 1999-06-11 | 2000-12-13 | Merck & Co Inc | Synthesis of 3,5-bis(trifluoromethyl)benzoic acid |
| CN102491894A (en) * | 2011-11-30 | 2012-06-13 | 泰安渤洋化工科技有限公司 | Preparation method of 2,4,6-trimethylbenzoic acid |
| CN103319330A (en) * | 2013-07-09 | 2013-09-25 | 泰山医学院 | Method for preparing 2,4-dimethylbenzoic acid by using carbon dioxide carboxylation process |
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| CN108047031A (en) * | 2017-12-19 | 2018-05-18 | 湖南久日新材料有限公司 | The preparation method of 2,4,6- tri-methyl chlorides and its application for being used to prepare phosphorous photoinitiator |
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2018
- 2018-12-04 CN CN201811473780.6A patent/CN109320412B/en active Active
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| GB2350837A (en) * | 1999-06-11 | 2000-12-13 | Merck & Co Inc | Synthesis of 3,5-bis(trifluoromethyl)benzoic acid |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113698287A (en) * | 2021-08-27 | 2021-11-26 | 中国石油化工股份有限公司 | Method for preparing p-methylbenzoic acid by catalyzing carbon dioxide and methylbenzene |
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