CN104151157B - A kind of preparation method of methoxybenzoic acid - Google Patents
A kind of preparation method of methoxybenzoic acid Download PDFInfo
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- C07C51/00—Preparation of carboxylic acids or their salts, halides or anhydrides
- C07C51/41—Preparation of salts of carboxylic acids
- C07C51/412—Preparation of salts of carboxylic acids by conversion of the acids, their salts, esters or anhydrides with the same carboxylic acid part
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- C—CHEMISTRY; METALLURGY
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- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C253/00—Preparation of carboxylic acid nitriles
- C07C253/30—Preparation of carboxylic acid nitriles by reactions not involving the formation of cyano groups
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Abstract
The invention discloses the preparation method of a kind of methoxybenzoic acid alkali metal salt as shown in formula B; comprise the following steps: step one: under inert gas shielding; in methanol; compound A is carried out nucleophilic substitution with Feldalat NM; reaction temperature is 80 DEG C～150 DEG C, and reaction pressure is 0.18MPa～1.4MPa；Step 2: directly mixed with alkali metal hydroxide and water by step one gained solution, removes methanol and carries out hydrolysis, obtaining compound B, and reaction temperature is 90 DEG C～190 DEG C, and described alkali metal hydroxide is sodium hydroxide and/or potassium hydroxide.Prepared compound B is carried out acidification reaction with acid, prepares the methoxybenzoic acid as shown in formula C.This method raw material is cheap and easy to get, the use reagent of inexpensive safety, alkali consumption are little, low in the pollution of the environment, use one kettle way, simple to operate, yield is high, is suitable for industrialized production.
Description
Technical field
The present invention relates to the preparation method of a kind of methoxybenzoic acid.
Background technology
Adjacent (to) methoxybenzoic acid be also called neighbour (to) anisic acid, be important organic intermediate.
O-methoxybenzoic acid, for synthetic perfume, medicine, anticorrosion；P-Methoxybenzoic acid, is mainly used as
The intermediate of the medicine such as atlansil, also can be used for spice.
Adjacent (to) preparation method of methoxybenzoic acid mainly have neighbour (to) hydroxy benzoic acid method, neighbour (to)
Methoxybenzaldehyde method, neighbour (to) methoxy benzyl alcohol method, neighbour (to) methoxy cyanophenyl method and adjacent (to)
Methylphenol method.
1, adjacent (to) hydroxy benzoic acid method.With corresponding hydroxy benzoic acid as raw material, at alkaline solution
In, carrying out methylation reaction with dimethyl sulfate or iodomethane etc., the methoxybenzoic acid sodium of generation is last
Use hydrochloric acid desalination, can prepare respectively adjacent (to) methoxybenzoic acid.The shortcoming of the method be raw material adjacent (to)
Hydroxy benzoic acid price is higher, lacks cost advantage.In addition, methylating reagent uses toxic articles dimethyl sulfate
Ester and consume more alkali when methylating, produces again by-product novalgin, pollutes environment.Methylate
Reagent iodomethane is expensive, and cost of material is high.
2, adjacent (to) hydroxy benzaldehyde method.With adjacent (to) methoxybenzaldehyde be raw material through methylating,
The prepared corresponding neighbour of oxidation (to) methoxybenzoic acid.The raw material of the method adjacent (to) methoxybenzene first
Aldehyde price is high and source is few.
3, adjacent (to) salicylic alcohol method.With adjacent (to) salicylic alcohol be raw material through methylating,
Oxidation obtain corresponding adjacent (to) methoxybenzoic acid.Use when methylating toxic articles dimethyl sulfate with
More alkali, raw material during oxidation is more expensive with catalyst, unsuitable industrialized production.
4, adjacent (to) 4-hydroxy-benzonitrile method.With adjacent (to) 4-hydroxy-benzonitrile is that raw material is through methylating, hydrolyzing
Obtain corresponding adjacent (to) methoxybenzoic acid.Dimethyl sulfate or iodomethane can be used when methylating,
Use toxic articles dimethyl sulfate to make methylating reagent and can consume more alkali, methylating reagent iodomethane valency
Lattice are more expensive.And raw material adjacent (to) 4-hydroxy-benzonitrile is more expensive, cost of material is high.
5, adjacent (to) methylphenol method.With adjacent (to) methylphenol is that raw material is through methylating, aoxidizing
Obtain corresponding adjacent (to) methoxybenzoic acid.Dimethyl sulfate or iodomethane can be used when methylating,
Use toxic articles dimethyl sulfate to make methylating reagent and can consume more alkali, methylating reagent iodomethane valency
Lattice are more expensive.Using cobalt dihromide and manganese dibromide to make catalyst during oxidation methyl, glacial acetic acid, acetic anhydride are made molten
Agent, is passed through oxygen and aoxidizes, and cost of material is higher.
CN200610019306.7 discloses and carries out substitution reaction system with 2,6-dichlorobenzonitrile and Feldalat NM
Standby 2,6-dimethoxy cyanophenyl；CN201410058806.6 discloses o-chloro benzonitrile take with Feldalat NM
O-methoxy cyanophenyl is prepared for reaction；Gutmann B, Chemistry 2010,16 (40): 12182-94 intermediary
The O-methoxy cyanophenyl hydrolysis acidification that continued prepares o-methoxybenzoic acid.
Summary of the invention
The technical problem to be solved is the preparation side in order to overcome existing methoxybenzoic acid
Use severe toxicity or expensive reagent in method, that alkali consumption is big, environmental pollution is big, operation is complicated, yield is low etc. is scarce
Putting and provide the preparation method of a kind of methoxybenzoic acid, this method raw material is cheap and easy to get, it is cheap to use
The reagent of safety, alkali consumption are little, low in the pollution of the environment, use one kettle way, simple to operate, yield is high, suitable
Close industrialized production.
The invention provides the preparation method of a kind of methoxybenzoic acid alkali metal salt as shown in formula B, its
Comprise the following steps:
Step one: under inert gas shielding, in methanol, carries out nucleophilic by compound A with Feldalat NM and takes
Generation reaction, reaction temperature is 80 DEG C～150 DEG C, and reaction pressure is 0.18MPa～1.4MPa；
Step 2: directly mixed with alkali metal hydroxide and water by step one gained solution, removes methanol
And carry out hydrolysis, and obtaining compound B, reaction temperature is 90 DEG C～190 DEG C, described alkali gold
Belonging to hydroxide is sodium hydroxide and/or potassium hydroxide；
Wherein, M is sodium or potassium；R1During for Cl, R2=H, R3=OCH3, R4=H；Or, R2
During for Cl, R1=H, R3=H, R4=OCH3。
In the preparation method of compound B, the preferred helium of described noble gas, argon, neon and nitrogen
One or more in gas.
In the preparation method of compound B, described methanol is preferred with the mass ratio of compound A
0.8～1.7:1, further preferred 1.0～1.4:1.
In the preparation method of compound B, described Feldalat NM is preferred with the mol ratio of compound A
0.9～1.8:1, further preferred 1.0～1.5:1.
In the preparation method of compound B, the temperature of described nucleophilic substitution preferably 100 DEG C
～130 DEG C, further preferred 100 DEG C～120 DEG C.
In the preparation method of compound B, the pressure of described nucleophilic substitution is preferred
0.2MPa～0.8MPa, further preferred 0.3MPa～0.5MPa.
In the preparation method of compound B, the process of described nucleophilic substitution can use this area
In routine monitoring method (such as TLC, HPLC or NMR) be monitored, typically with compound
It is reaction end when A no longer reacts, preferably 1 hour～10 hours response time, further preferred 2
Hour～4 hours.
In the preparation method of compound B, the preferred sodium hydroxide of described alkali metal hydroxide.
In the preparation method of compound B, described alkali metal hydroxide and compound A mole
Ratio preferably 1.0～5.0:1, further preferred 1.0～1.2:1, such as 1.1:1.
In the preparation method of compound B, described water is preferred with the mass ratio of compound A
0.3～5.0:1, further preferred 0.5～1.0:1, such as 0.75:1.
In the preparation method of compound B, the heating means of described hydrolysis can be conventional adding
By the use of thermal means, including microwave heating.
In the preparation method of compound B, the temperature of described hydrolysis preferably 90 DEG C～100 DEG C,
Further preferred 95 DEG C～100 DEG C.
In the preparation method of compound B, the preferred 0.1MPa of pressure of described hydrolysis.
In the preparation method of compound B, the process of described hydrolysis can use in this area
Routine monitoring method (such as TLC, HPLC or NMR) is monitored, typically with methoxy cyanophenyl
No longer reaction time be reaction end, preferably 1 hour～24 hours response time, further preferred 2 hours～
8 hours.
The invention provides the preparation method of a kind of methoxybenzoic acid as shown in formula C, it includes following
Step:
The preparation method of the methoxybenzoic acid alkali metal salt as shown in formula B prepares as described above
Compound B, carries out acidification reaction by compound B with acid, obtains compound C；
Wherein, R3、R4Definition with M is the most same as above.
The preparation method of described methoxybenzoic acid can be the routine of such acidification reaction in this area
Method, particularly preferred following reaction method and condition in the present invention:
In the preparation method of compound C, described acid preferably hydrochloric acid and/or sulphuric acid, further preferably
Hydrochloric acid.
In the preparation method of compound C, preferred pH≤6 of pH of the reactant liquor of described acidification reaction,
Further preferably pH≤4.
On the basis of meeting common sense in the field, above-mentioned each optimum condition, can combination in any, i.e. get Ben Fa
Bright each preferred embodiments.
Agents useful for same of the present invention and raw material are the most commercially.
The most progressive effect of the present invention is: raw material is cheap and easy to get, use the reagent of inexpensive safety, consumption
Alkali number is little, low in the pollution of the environment, use one kettle way, simple to operate, yield is high, is suitable for industrialized production.
Detailed description of the invention
Further illustrate the present invention below by the mode of embodiment, but the most therefore limit the present invention to
Among described scope of embodiments.The experimental technique of unreceipted actual conditions in the following example, according to often
Rule method and condition, or select according to catalogue.
Embodiment 1
In the autoclave of 100ml, add 30% Feldalat NM 16.2g, o-chloro benzonitrile 0.1mol, use nitrogen
After displaced air three times, sealed reactor, be warmed up to 100 DEG C～120 DEG C, reaction pressure about 0.3Mpa～
0.5Mpa, and it is incubated 2 hours～4 hours, HPLC analyzes o-chloro benzonitrile, and < 0.5% is terminal, will reaction
Liquid cools to less than 50 DEG C, is added dropwise to 30% liquid caustic soda 14.7g, intensification Distillation recovery methanol, works as Nei Wenda
During to 100 DEG C, repack backflow into, and maintain the reflux for reacting 2 hours～8 hours, when O-methoxy benzene
< 0.5% is terminal to nitrile, is cooled down by reactant liquor, regulates PH < 4 with hydrochloric acid, separate out a large amount of white solid, mistake
Filter, after washing, dries, obtains o-methoxybenzoic acid.
Embodiment 2
In the autoclave of 100ml, add 30% Feldalat NM 27.0g, o-chloro benzonitrile 0.1mol, use nitrogen
After displaced air three times, sealed reactor, be warmed up to 80 DEG C～100 DEG C, reaction pressure about 0.2Mpa～
0.4Mpa, and it is incubated 2 hours～4 hours, HPLC analyzes o-chloro benzonitrile, and < 0.5% is terminal, will reaction
Liquid cools to less than 50 DEG C, is added dropwise to 30% liquid caustic soda 14.7g, intensification Distillation recovery methanol, works as Nei Wenda
During to 100 DEG C, repack backflow into, and maintain the reflux for reacting 2 hours～8 hours, when O-methoxy benzene
< 0.5% is terminal to nitrile, is cooled down by reactant liquor, regulates PH < 4 with hydrochloric acid, separate out a large amount of white solid, mistake
Filter, after washing, dries, obtains o-methoxybenzoic acid.
Embodiment 3
In the autoclave of 200ml, add 30% Feldalat NM 32.4g, o-chloro benzonitrile 0.1mol, use nitrogen
After displaced air three times, sealed reactor, be warmed up to 130 DEG C～150 DEG C, reaction pressure about 0.8Mpa～
1.4Mpa, and it is incubated 2 hours～4 hours, HPLC analyzes o-chloro benzonitrile, and < 0.5% is terminal, will reaction
Liquid cools to less than 50 DEG C, is added dropwise to 30% liquid caustic soda 14.7g, intensification Distillation recovery methanol, works as Nei Wenda
During to 100 DEG C, repack backflow into, and maintain the reflux for reacting 2 hours～8 hours, when O-methoxy benzene
< 0.5% is terminal to nitrile, is cooled down by reactant liquor, regulates PH < 4 with hydrochloric acid, separate out a large amount of white solid, mistake
Filter, after washing, dries, obtains o-methoxybenzoic acid.
Embodiment 4
In the autoclave of 100ml, add 30% Feldalat NM 16.2g, to 6-chlorophenyl nitrile 0.1mol, use nitrogen
After displaced air three times, sealed reactor, be warmed up to 100 DEG C～120 DEG C, reaction pressure about 0.3Mpa～
0.5Mpa, and it is incubated 2 hours～4 hours, to 6-chlorophenyl nitrile, < 0.5% is terminal, will reaction in HPLC analysis
Liquid cools to less than 50 DEG C, is added dropwise to 30% liquid caustic soda 14.7g, intensification Distillation recovery methanol, works as Nei Wenda
During to 100 DEG C, repack backflow into, and maintain the reflux for reacting 2 hours～8 hours, when to methoxybenzene
< 0.5% is terminal to nitrile, is cooled down by reactant liquor, regulates PH < 4 with hydrochloric acid, separate out a large amount of white solid, mistake
Filter, after washing, dries, obtains p-Methoxybenzoic acid.
Embodiment 5
In the autoclave of 100ml, add 30% Feldalat NM 27.0g, to 6-chlorophenyl nitrile 0.1mol, use nitrogen
After displaced air three times, sealed reactor, be warmed up to 80 DEG C～100 DEG C, reaction pressure about 0.2Mpa～
0.4Mpa, and it is incubated 2 hours～4 hours, to 6-chlorophenyl nitrile, < 0.5% is terminal, will reaction in HPLC analysis
Liquid cools to less than 50 DEG C, is added dropwise to 30% liquid caustic soda 14.7g, intensification Distillation recovery methanol, works as Nei Wenda
During to 100 DEG C, repack backflow into, and maintain the reflux for reacting 2 hours～8 hours, when to methoxybenzene
< 0.5% is terminal to nitrile, is cooled down by reactant liquor, regulates PH < 4 with hydrochloric acid, separate out a large amount of white solid, mistake
Filter, after washing, dries, obtains p-Methoxybenzoic acid.
Embodiment 6
In the autoclave of 200ml, add 30% Feldalat NM 32.4g, to 6-chlorophenyl nitrile 0.1mol, use nitrogen
After displaced air three times, sealed reactor, be warmed up to 130 DEG C～150 DEG C, reaction pressure about 0.8Mpa～
1.4Mpa, and it is incubated 2 hours～4 hours, to 6-chlorophenyl nitrile, < 0.5% is terminal, will reaction in HPLC analysis
Liquid cools to less than 50 DEG C, is added dropwise to 30% liquid caustic soda 14.7g, intensification Distillation recovery methanol, works as Nei Wenda
During to 100 DEG C, repack backflow into, and maintain the reflux for reacting 2 hours～8 hours, when to methoxybenzene
< 0.5% is terminal to nitrile, is cooled down by reactant liquor, regulates PH < 4 with hydrochloric acid, separate out a large amount of white solid, mistake
Filter, after washing, dries, obtains p-Methoxybenzoic acid.
Being implemented by above example, the yield of o-methoxybenzoic acid and p-Methoxybenzoic acid all reaches
95%, analyze content > 98%.
Claims (10)
1. the preparation method of the methoxybenzoic acid alkali metal salt as shown in formula B, it is characterised in that
Comprise the following steps:
Step one: under inert gas shielding, in methanol, carries out nucleophilic by compound A with Feldalat NM and takes
Generation reaction, reaction temperature is 80 DEG C～150 DEG C, and reaction pressure is 0.18MPa～1.4MPa；
Step 2: directly mixed with alkali metal hydroxide and water by step one gained solution, removes methanol
And carry out hydrolysis, and obtaining compound B, reaction temperature is 90 DEG C～190 DEG C, described alkali gold
Belonging to hydroxide is sodium hydroxide and/or potassium hydroxide；
Wherein, M is sodium or potassium；R1During for Cl, R2=H, R3=OCH3, R4=H；Or, R2
During for Cl, R1=H, R3=H, R4=OCH3。
2. preparation method as claimed in claim 1, it is characterised in that:
Described noble gas is one or more in helium, argon, neon and nitrogen；
And/or,
Described methanol is 0.8～1.7:1 with the mass ratio of described compound A；
And/or,
Described Feldalat NM is 0.9～1.8:1 with the mol ratio of described compound A；
And/or,
Described alkali metal hydroxide is sodium hydroxide；
And/or,
Described alkali metal hydroxide is 1.0～5.0:1 with the mol ratio of described compound A；
And/or,
Described water is 0.3～5.0:1 with the mass ratio of described compound A.
3. preparation method as claimed in claim 2, it is characterised in that:
Described methanol is 1.0～1.4:1 with the mass ratio of described compound A；
And/or,
Described Feldalat NM is 1.0～1.5:1 with the mol ratio of described compound A；
And/or,
Described alkali metal hydroxide is 1.0～1.2:1 with the mol ratio of described compound A；
And/or,
Described water is 0.5～1.0:1 with the mass ratio of described compound A.
4. preparation method as claimed in claim 1, it is characterised in that:
The temperature of described nucleophilic substitution is 100 DEG C～130 DEG C；
And/or,
The pressure of described nucleophilic substitution is 0.2MPa～0.8MPa；
And/or,
Till when the time of described nucleophilic substitution no longer reacts with compound A；
And/or,
The temperature of described hydrolysis is 90 DEG C～100 DEG C；
And/or,
The pressure of described hydrolysis is 0.1MPa；
And/or,
Till when the time of described hydrolysis no longer reacts with methoxy cyanophenyl.
5. preparation method as claimed in claim 4, it is characterised in that:
The temperature of described nucleophilic substitution is 100 DEG C～120 DEG C；
And/or,
The pressure of described nucleophilic substitution is 0.3MPa～0.5MPa；
And/or,
The temperature of described hydrolysis is 95 DEG C～100 DEG C.
6. the preparation method of the methoxybenzoic acid as shown in formula C, it is characterised in that include following
Step:
Step a: according to the methoxybenzoic acid as shown in formula B as described in any one of Claims 1 to 5
The preparation method of alkali metal salt prepares compound B；
Step b: compound B step a prepared and acid carry out acidification reaction, obtain compound C；
Wherein, M is sodium or potassium；R3=OCH3, R4=H；Or R3=H, R4=OCH3。
7. preparation method as claimed in claim 6, it is characterised in that: described acid be hydrochloric acid and/or
Sulphuric acid.
8. preparation method as claimed in claim 7, it is characterised in that: described acid is hydrochloric acid.
9. preparation method as claimed in claim 6, it is characterised in that: described acidification reaction anti-
The pH answering liquid is pH≤6.
10. preparation method as claimed in claim 9, it is characterised in that: described acidification reaction anti-
The pH answering liquid is pH≤4.
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