1975-50-4

Basic information

• Product Name: 2-Methyl-3-nitrobenzoic acid
• Synonyms: 2-methyl-3-nitro-benzoicaci;AKOS BB-9542;3-NITRO-O-TOLUIC ACID;3-NITRO-2-METHYLBENZOIC ACID;2-METHYL-3-NITROBENZOIC ACID;3-Nitro-2-Toluic Acid;Benzoic acid, 2-methyl-3-nitro-;2-METHYL-3-NITROBENZOIC ACID / 3-NITRO-O-TOLUIC ACID
• CAS NO: 1975-50-4
• Molecular Formula: C₈H₇NO₄
• Molecular Weight: 181.15
• EINECS: 217-826-4
• Product Categories: FINE Chemical & INTERMEDIATES;Aromatic Carboxylic Acids, Amides, Anilides, Anhydrides & Salts;Benzoic acid;Organic acids;Building Blocks;C8;Carbonyl Compounds;Carboxylic Acids;Chemical Synthesis;Organic Building Blocks
• Mol File: 1975-50-4.mol
• Article Data: 15

Chemical Properties

• Melting Point: 182-184 °C(lit.)
• Boiling Point: 314.24°C (rough estimate)
• Flash Point: 151.9 °C
• Appearance: white crystal powder
• Density: 1.4283 (rough estimate)
• Vapor Pressure: 4.21E-05mmHg at 25°C
• Refractive Index: 1.5468 (estimate)
• Storage Temp.: Store below +30°C.
• PKA: 3.03±0.20(Predicted)
• Water Solubility: <0.1 g/100 mL at 22℃
• BRN: 2050096
• CAS DataBase Reference: 2-Methyl-3-nitrobenzoic acid(CAS DataBase Reference)
• NIST Chemistry Reference: 2-Methyl-3-nitrobenzoic acid(1975-50-4)
• EPA Substance Registry System: 2-Methyl-3-nitrobenzoic acid(1975-50-4)

Safety Data

• Hazard Codes: Xi,Xn
• Statements: 36/37/38-20/21/22
• Safety Statements: 26-36-36/37/39-22
• WGK Germany: 3
• TSCA: Yes
• Hazardous Substances Data: 1975-50-4(Hazardous Substances Data)

Usage

Chemical Properties

white crystal powder

Uses

Different sources of media describe the Uses of 1975-50-4 differently. You can refer to the following data:
1. 3-Nitro-o-toluic Acid, is a building block used for the synthesis of various compounds. It is an intermediate for the synthesis of 4-(Piperazin-1-ylmethyl)-N1-arylsulfonyl indole derivatives as 5-HT6 receptor ligands.
2. 2-Methyl-3-nitrobenzoic acid was used as starting reagent in the synthesis of methyl 2-methyl-3-nitrobenzoate and 2,3-unsubstituted indoles.

General Description

Fine needles or light beige powder.

Air & Water Reactions

Insoluble in water.

Reactivity Profile

2-Methyl-3-nitrobenzoic acid is a nitrated carboxylic acid. Carboxylic acids donate hydrogen ions if a base is present to accept them. They react in this way with all bases, both organic (for example, the amines) and inorganic. Their reactions with bases, called "neutralizations", are accompanied by the evolution of substantial amounts of heat. Neutralization between an acid and a base produces water plus a salt. Carboxylic acids with six or fewer carbon atoms are freely or moderately soluble in water; those with more than six carbons are slightly soluble in water. Soluble carboxylic acid dissociate to an extent in water to yield hydrogen ions. The pH of solutions of carboxylic acids is therefore less than 7.0. Many insoluble carboxylic acids react rapidly with aqueous solutions containing a chemical base and dissolve as the neutralization generates a soluble salt. Carboxylic acids in aqueous solution and liquid or molten carboxylic acids can react with active metals to form gaseous hydrogen and a metal salt. Such reactions occur in principle for solid carboxylic acids as well, but are slow if the solid acid remains dry.

Fire Hazard

Flash point data for 2-Methyl-3-nitrobenzoic acid is not available. 2-Methyl-3-nitrobenzoic acid is probably combustible.

InChI:InChI=1/C8H7NO4/c1-5-6(8(10)11)3-2-4-7(5)9(12)13/h2-4H,1H3,(H,10,11)/p-1

Synthetic route

2,3-dimethylnitrobenzene (83-41-0) → 2-methyl-3-nitrobenzic acid (1975-50-4)

Conditions	Yield
With dihydrogen peroxide; cobalt(II) acetate; manganese(II) acetate; hexanoic acid at 60℃; for 12h; Temperature; Reagent/catalyst;	87%
(i) Br2, KOH, (ii) (hydrolysis); Multistep reaction;
Multi-step reaction with 3 steps 1: H2SO4, CrO3 2: H2SO4 3: KMnO4, NaHCO3 View Scheme
With nitric acid at 125℃; for 1h; Temperature; High pressure;
With oxygen; cobalt(II) acetate; manganese(II) acetate; acetic acid; sodium bromide In water at 133 - 136℃; under 7500.75 - 11251.1 Torr; for 7.5h; Reagent/catalyst; Temperature; Pressure;	32 g

2-methyl-3-nitro-benzoic acid methyl ester (59382-59-1) + 4-fluorobenzaldehyde (459-57-4) → 2-[trans-2-(4-fluorophenyl)-vinyl]-3-nitrobenzoic acid (917614-64-3) + 2-methyl-3-nitrobenzic acid (1975-50-4)

Conditions	Yield
With 1,8-diazabicyclo[5.4.0]undec-7-ene In dimethyl sulfoxide at 20 - 50℃; for 12.5h;	A 84% B n/a

ortho-methylbenzoic acid (118-90-1) → 2-methyl-3-nitrobenzic acid (1975-50-4) + 5-nitro-o-toluic acid (1975-52-6)

Conditions	Yield
With nitric acid at 0℃;
With nitric acid
With nitric acid

2-Methyl-benzoic acid methyl ester (89-71-4) → 2-methyl-3-nitrobenzic acid (1975-50-4) + methyl 2-methyl-5-nitrobenzoate (77324-87-9)

Conditions	Yield
bei der Nitrierung;

2-methyl-3-nitrobenzonitrile (71516-35-3) → 2-methyl-3-nitrobenzic acid (1975-50-4)

Conditions	Yield
With sulfuric acid at 150℃;

2,3-dimethylnitrobenzene (83-41-0) → 2-methyl-3-nitrobenzic acid (1975-50-4) + 2-methyl-6-nitrobenzoic acid (13506-76-8) + 3-nitrophthalic acid (603-11-2)

Conditions	Yield
With potassium permanganate; cetyltrimethylammonim bromide In water at 75℃; for 4h; Product distribution; effect of the amount of KMnO4; further catalysts;
With potassium permanganate; cetyltrimethylammonim bromide In water at 75℃; for 4h; Yield given. Yields of byproduct given;
With potassium permanganate; tetrabutylammomium bromide In water
With oxygen; nitric acid at 130 - 140℃; under 16501.7 - 18751.9 Torr; for 7h; Temperature; Pressure;

3-formyl-2-methyl-1-nitrobenzene (23876-12-2) → 2-methyl-3-nitrobenzic acid (1975-50-4)

Conditions	Yield
With potassium permanganate; sodium hydrogencarbonate

2-Methylbenzonitrile (529-19-1) → 2-methyl-3-nitrobenzic acid (1975-50-4)

Conditions	Yield
Multi-step reaction with 2 steps 1: alcoholic potash 2: concentrated nitric acid View Scheme

o-xylene (95-47-6) → 2-methyl-3-nitrobenzic acid (1975-50-4)

Conditions	Yield
Multi-step reaction with 2 steps 1: diluted nitric acid 2: concentrated nitric acid View Scheme
Multi-step reaction with 2 steps 1: nitric acid; sulfuric acid / water / 0.5 h / -10 °C 2: nitric acid / 1 h / 125 °C / High pressure View Scheme

3,4-dimethylbenzoic acid (619-04-5) → 2-methyl-3-nitrobenzic acid (1975-50-4)

Conditions	Yield
Multi-step reaction with 3 steps 1: bei der Destillation 2: diluted nitric acid 3: concentrated nitric acid View Scheme

2-methyl-3-nitrobenzol-1-methandiol diacetate (23876-11-1) → 2-methyl-3-nitrobenzic acid (1975-50-4)

Conditions	Yield
Multi-step reaction with 2 steps 1: H2SO4 2: KMnO4, NaHCO3 View Scheme

2,3-dimethylnitrobenzene (83-41-0) → 2-methyl-3-nitrobenzic acid (1975-50-4) + (2-methyl-3-nitrophenyl)methanol (23876-13-3) + 3-formyl-2-methyl-1-nitrobenzene (23876-12-2)

Conditions	Yield
Stage #1: 2,3-dimethylnitrobenzene With C88H64CrMnN16O; cobalt isooctanoate; oxygen; 4-methyl-2-hydroxy-1(H)-isoindole-1,3-dione at 100℃; under 750.075 Torr; Stage #2: With water at 50℃; under 750.075 Torr;

2,3-dimethylnitrobenzene (83-41-0) → 2-methyl-3-nitrobenzic acid (1975-50-4) + 2-methyl-6-nitrobenzoic acid (13506-76-8) + 3-nitrophthalic acid (603-11-2) + C8H7NO5

Conditions	Yield
With oxygen; nitric acid at 145 - 150℃; under 26252.6 - 30003 Torr; for 8h; Temperature; Pressure;

2,3-dimethylnitrobenzene (83-41-0) + butan-1-ol (71-36-3) → butyl 3-nitro-2-methylbenzoate (59383-02-7) + 2-methyl-3-nitrobenzic acid (1975-50-4) + 2-methyl-6-nitrobenzoic acid (13506-76-8)

Conditions	Yield
Stage #1: 2,3-dimethylnitrobenzene With oxygen; nitric acid at 130 - 140℃; under 16501.7 - 18751.9 Torr; for 7h; Stage #2: butan-1-ol With toluene-4-sulfonic acid Reflux;

butyl 3-nitro-2-methylbenzoate (59383-02-7) → 2-methyl-3-nitrobenzic acid (1975-50-4)

Conditions	Yield
With sodium hydroxide In water at 100℃;	135 g

2-methyl-3-nitrobenzic acid (1975-50-4) → (2-methyl-3-nitrophenyl)methanol (23876-13-3)

Conditions	Yield
With borane In tetrahydrofuran	100%
Stage #1: 2-methyl-3-nitrobenzic acid With sodium tetrahydroborate In tetrahydrofuran at 20℃; for 0.5h; Stage #2: With methanesulfonic acid In tetrahydrofuran	84%
Multi-step reaction with 2 steps 1: SOCl2 2: NaBH4 / tetrahydrofuran View Scheme

2-methyl-3-nitrobenzic acid (1975-50-4) → 5-bromo-2-methyl-3-nitro-benzoic acid (107650-20-4)

Conditions	Yield
With 1,3-dibromo-5,5-dimethylimidazolidine-2,4-dione; sulfuric acid at 20℃; for 5h; Product distribution / selectivity;	100%
Stage #1: 2-methyl-3-nitrobenzic acid With 1,3-dibromo-5,5-dimethylimidazolidine-2,4-dione; sulfuric acid at 20℃; for 5h; Stage #2: With water Product distribution / selectivity; Cooling;	100%
With 1,3-dibromo-5,5-dimethylimidazolidine-2,4-dione; sulfuric acid at 0℃; for 5h;	100%

2-methyl-3-nitrobenzic acid (1975-50-4) + copper(l) cyanide → C9H6N2O3

Conditions	Yield
Stage #1: copper(l) cyanide With sodium iodide In acetonitrile at 20℃; for 0.0833333h; Inert atmosphere; Stage #2: 2-methyl-3-nitrobenzic acid In acetonitrile at 20℃; for 1h; Inert atmosphere;	100%

2-methyl-3-nitrobenzic acid (1975-50-4) → 2-methyl-3-nitrobenzoyl chloride (39053-41-3)

Conditions	Yield
With thionyl chloride at 60℃; for 25.5h; Inert atmosphere;	99%
With thionyl chloride for 6h; Reflux;	99%
With thionyl chloride at 60℃; for 24h;	98%

methanol (67-56-1) + 2-methyl-3-nitrobenzic acid (1975-50-4) → 2-methyl-3-nitro-benzoic acid methyl ester (59382-59-1)

Conditions	Yield
With sulfuric acid for 24h; Inert atmosphere; Reflux;	99%
Stage #1: 2-methyl-3-nitrobenzic acid With oxalyl dichloride; N,N-dimethyl-formamide In dichloromethane at 20℃; Stage #2: methanol In dichloromethane for 0.0833333h;	99%
With thionyl chloride for 2h; Reflux;	98%

2-methyl-3-nitrobenzic acid (1975-50-4) → 3-amino-2-methylbenzoic acid (52130-17-3)

Conditions	Yield
With hydrogen; palladium on activated charcoal In ethanol at 20℃; Catalytic hydrogenation;	98%
With palladium on activated charcoal; hydrogen In ethyl acetate for 15h;	90%
With ammonium hydroxide; hydrogen sulfide

ethanol (64-17-5) + 2-methyl-3-nitrobenzic acid (1975-50-4) → ethyl 2-methyl-3-nitrobenzoate (59382-60-4)

Conditions	Yield
With sulfuric acid at 20℃; for 168h;	98%
With thionyl chloride at 0 - 70℃;	79%

1-bromo-hexane (111-25-1) + 2-methyl-3-nitrobenzic acid (1975-50-4) → hexyl 2-methyl-3-nitrobenzoate (59383-04-9)

Conditions	Yield
With potassium carbonate In acetone for 96h; Reflux;	98%

2-methyl-3-nitrobenzic acid (1975-50-4) + dimethyl sulfate (77-78-1) → 2-methyl-3-nitro-benzoic acid methyl ester (59382-59-1)

Conditions	Yield
Stage #1: 2-methyl-3-nitrobenzic acid With potassium carbonate In acetone at 20℃; for 0.166667h; Stage #2: dimethyl sulfate In acetone for 4h; Reflux;	98%
Stage #1: 2-methyl-3-nitrobenzic acid; dimethyl sulfate In acetone at 25 - 30℃; for 0.166667h; Stage #2: With potassium carbonate In acetone at 25 - 30℃; for 1.5h;	97.53%

2-methyl-3-nitrobenzic acid (1975-50-4) → 5-iodo-2-methyl-3-nitrobenzoic acid

Conditions	Yield
With N-iodo-succinimide; sulfuric acid at 60℃; for 2h;	98%

2-methyl-3-nitrobenzic acid (1975-50-4) + 4-bromo-aniline (106-40-1) → N-(4-bromophenyl)-2-methyl-3-nitrobenzamide

Conditions	Yield
With O-(benzotriazol-1-yl)-N,N,N',N'-tetramethyluronium tetrafluoroborate; N-ethyl-N,N-diisopropylamine In dichloromethane at 0 - 20℃; for 3h;	89%

d(4)-methanol (811-98-3) + 2-methyl-3-nitrobenzic acid (1975-50-4) → C9H6(2)H3NO4

Conditions	Yield
With sulfuric acid for 72h; Heating;	88%

di-tert-butyl dicarbonate (24424-99-5) + 2-methyl-3-nitrobenzic acid (1975-50-4) → 3-<<(1,1-dimethylethoxy)carbonyl>amino>-2-methylbenzoic acid (143617-89-4)

Conditions	Yield
With hydrogen; palladium on activated charcoal In N,N-dimethyl-formamide under 2585.7 Torr; for 2.5h;	86%

2-methyl-3-nitrobenzic acid (1975-50-4) + methyl iodide (74-88-4) → 2-methyl-3-nitro-benzoic acid methyl ester (59382-59-1)

Conditions	Yield
With sodium hydrogencarbonate In N,N-dimethyl-formamide at 60℃; for 24h;	86%
With potassium hydrogencarbonate 1.) DMF, 40 deg C, 2.) DMF, RT, 12 h; Yield given; Multistep reaction;

1,3-dibromo-5,5-dimethylimidazolidine-2,4-dione (77-48-5) + 2-methyl-3-nitrobenzic acid (1975-50-4) → 5-bromo-2-methyl-3-nitro-benzoic acid (107650-20-4)

Conditions	Yield
With sulfuric acid at 20℃; for 5h;	84%

2-methyl-3-nitrobenzic acid (1975-50-4) + N,N-dimethyl-formamide dimethyl acetal (4637-24-5) → Methyl trans-2-<β-(dimethylamino)vinyl>-3-nitrobenzoate (73816-11-2)

Conditions	Yield
In N,N-dimethyl-formamide at 115℃; for 24h;	80%

2-methyl-3-nitrobenzic acid (1975-50-4) + (+)-ent-Cholesterol (57-88-5, 474-77-1, 14868-17-8, 23820-70-4, 34026-89-6, 57759-45-2, 71869-93-7, 121155-47-3, 138456-89-0) → C35H51NO4

Conditions	Yield
With dmap; dicyclohexyl-carbodiimide In dichloromethane at 20℃; for 12h; Inert atmosphere;	80%

2'-hydroxy-6'-methoxyacetophenone (703-23-1) + 2-methyl-3-nitrobenzic acid (1975-50-4) → 6'-methoxy-2'-(2-methyl-3-nitrobenzoyloxy)acetophenone (953129-19-6)

Conditions	Yield
With POCl2 In pyridine at 60 - 70℃; for 3h;	78%

2-methyl-3-nitrobenzic acid (1975-50-4) + triphenyltin(IV) hydroxide (76-87-9) → C27H25NO5Sn (1320287-24-8)

Conditions	Yield
In methanol for 1h; Reflux;	77.7%

2-methyl-3-nitrobenzic acid (1975-50-4) + magnesium bis(3-ethoxy-3-oxopropanoate) (37517-78-5) → ethyl 3-(2-methyl-3-nitrophenyl)-3-oxopropionate (136774-69-1)

Conditions	Yield
With 1,1'-carbonyldiimidazole In tetrahydrofuran	76%
With 1,1'-carbonyldiimidazole In tetrahydrofuran

2-methyl-3-nitrobenzic acid (1975-50-4) → 3-amino-2-methylbenzoic acid hydrochloride (141607-18-3)

Conditions	Yield
Stage #1: 2-methyl-3-nitrobenzic acid With hydrogen; sodium hydroxide In water at 150℃; under 76005.1 Torr; for 12h; Stage #2: With hydrogenchloride In water pH=2;	75%

2-methyl-3-nitrobenzic acid (1975-50-4) + 2-(4-methoxyphenyl)quinoline-4-carbohydrazide (51842-77-4) → 2-(4-methoxyphenyl)-4-(5-(2-methyl-3-nitrophenyl)-1,3,4-oxadiazol-2-yl)quinoline

Conditions	Yield
With trichlorophosphate Reflux;	75%

7-azaindoline (10592-27-5) + 2-methyl-3-nitrobenzic acid (1975-50-4) → (2,3-dihydro-1H-pyrrolo[2,3-b]pyridin-1-yl)(2-methylnitrophenyl)methanone

Conditions	Yield
Stage #1: 2-methyl-3-nitrobenzic acid With N-Bromosuccinimide; triphenylphosphine In dichloromethane at 0℃; for 0.5h; Stage #2: 7-azaindoline With triethylamine In dichloromethane at 20℃; for 1h;	75%

2-methyl-3-nitrobenzic acid (1975-50-4) + N,O-dimethylhydroxylamine*hydrochloride (6638-79-5) → N-methoxy-N,2-dimethyl-3-nitrobenzamide (177963-15-4)

Conditions	Yield
Stage #1: 2-methyl-3-nitrobenzic acid With N-Bromosuccinimide; triphenylphosphine In dichloromethane at 0℃; for 0.25h; Stage #2: N,O-dimethylhydroxylamine*hydrochloride With triethylamine In dichloromethane at 20℃; for 1h; chemoselective reaction;	74%
Stage #1: 2-methyl-3-nitrobenzic acid With 1,1'-carbonyldiimidazole In dichloromethane at 0 - 20℃; for 2.5h; Stage #2: N,O-dimethylhydroxylamine*hydrochloride In dichloromethane at 0 - 45℃; for 13.5h;	21%

2-methyl-3-nitrobenzic acid (1975-50-4) + 4-tert-butyl-5-(2,4-dichlorobenzyl)thiazol-2-amine → N-(4-(tert-butyl)-5-(2,4-dichlorobenzyl)thiazol-2-yl)-2-methyl-3-nitrobenzamide

Conditions	Yield
Stage #1: 2-methyl-3-nitrobenzic acid; 4-tert-butyl-5-(2,4-dichlorobenzyl)thiazol-2-amine With dmap In dichloromethane at 20℃; for 0.5h; Stage #2: With dicyclohexyl-carbodiimide In dichloromethane at 20℃;	74%

2-methyl-3-nitrobenzic acid (1975-50-4) + 6-methyldodec-7-yn-6-yl acetate → C21H29NO4

Conditions	Yield
With [RhCl2(p-cymene)]2; potassium carbonate In ethanol at 50℃; for 48h;	73%

active charcoal + 2-methyl-3-nitrobenzic acid (1975-50-4) → 3-acetoxy-2-methylbenzoic acid (168899-58-9)

Conditions	Yield
With sodium hydroxide; sulfuric acid; acetic anhydride; magnesium sulfate; sodium nitrite; palladium-carbon In pyridine; ethanol; ethyl acetate; toluene	72%

2-methyl-3-nitrobenzic acid (1975-50-4) + di(n-butyl)tin oxide (818-08-6) → C64H96N4O18Sn4 (1448543-52-9)

Conditions	Yield
In ethanol; hexane for 3h; Reflux;	72%

Upstream product

• 83-41-0 2,3-dimethylnitrobenzene 
• 59382-59-1 2-methyl-3-nitro-benzoic acid methyl ester 
• 459-57-4 4-fluorobenzaldehyde 
• 59383-02-7 butyl 3-nitro-2-methylbenzoate 
• 71-36-3 butan-1-ol 
• 23876-11-1 2-methyl-3-nitrobenzol-1-methandiol diacetate 
• 619-04-5 3,4-dimethylbenzoic acid 
• 95-47-6 o-xylene 
• 529-19-1 2-Methylbenzonitrile 
• 23876-12-2 3-formyl-2-methyl-1-nitrobenzene 
• 71516-35-3 2-methyl-3-nitrobenzonitrile 
• 89-71-4 2-Methyl-benzoic acid methyl ester 
• 118-90-1 ortho-methylbenzoic acid 

Downstream Products

• 28169-46-2 3,5-dinitro-o-toluic acid 
• 39830-66-5 methyl 1H-indole-4-carboxylate 
• 73816-11-2 Methyl trans-2-<β-(dimethylamino)vinyl>-3-nitrobenzoate 
• 178383-69-2 Mo₂(O₂CC₆H₃-2-CH₃-3-NO₂)4 
• 59382-87-5 4-nitrophenyl 3-nitro-2-methylbenzoate 
• 676347-14-1 (tert-butyl)dimethylsilyl 3-nitro-2-methylbenzoate 
• 632340-56-8 2-bromomethyl-3-nitro-benzoic acid 
• 177963-15-4 N-methoxy-N,2-dimethyl-3-nitrobenzamide 
• 59382-59-1 2-methyl-3-nitro-benzoic acid methyl ester 
• 130753-97-8 2-Methyl-3-nitro-benzoic acid 7-chloro-5-(2-chloro-phenyl)-1-methyl-2-oxo-2,3-dihydro-1H-benzo[e][1,4]diazepin-3-yl ester 
• 130753-95-6 2-Methyl-3-nitro-benzoic acid 7-chloro-1-methyl-2-oxo-5-phenyl-2,3-dihydro-1H-benzo[e][1,4]diazepin-3-yl ester 
• 130753-96-7 2-Methyl-3-nitro-benzoic acid 7-chloro-5-(2-chloro-phenyl)-2-oxo-2,3-dihydro-1H-benzo[e][1,4]diazepin-3-yl ester 
• 130753-94-5 2-Methyl-3-nitro-benzoic acid 7-chloro-2-oxo-5-phenyl-2,3-dihydro-1H-benzo[e][1,4]diazepin-3-yl ester 
• 77747-69-4 5-nitro-1H-isochromen-1-one 

Relevant articles and documents

Preparation of 2-arylindole-4-carboxylic amide derivatives

A practical, highly efficient protocol has been developed for the synthesis of functionalized 2-arylindole-4-carboxylic amide derivatives. Commercially available methyl 2-methyl-3-nitrobenzoate gave substituted nitrostyrene benzoic acids by reaction with aromatic aldehydes in the presence of DBU in DMSO. Conversion of these products to the desired amides was followed by Pd-catalyzed reductive cyclization employing carbon monoxide as the terminal reductant to provide the 2-arylindole-4-carboxylic amide derivatives in excellent overall yield for the simple three-step sequence.

Method for co-production 2-methyl-6-nitrobenzoic acid and 3-nitro-2-methylbenzoic acid

The invention discloses a method for co-production of 2-methyl-6-nitrobenzoic acid and 3-nitro-2-methylbenzoic acid. The method is characterized by comprising the following steps: (1) feeding 3-nitro-o-xylene and dilute nitric acid into an oxidation reaction kettle, carrying out heating, and conducting reacting under certain pressure by using oxygen as an oxidant; (2) after the reaction is finished, discharging an oxidation reaction solution to obtain a crude product; (3) washing the crude product with water, conducting esterifying, and performing distilling to recover a solvent after the reaction is finished, thereby obtaining an esterified concentrated solution; (4) adding alkali into the esterification concentrated solution to adjust a pH value, carrying out layering, and distilling anorganic layer under reduced pressure to recover 3-nitro-2-nitrobenzoic acid; and (5) extracting a water layer with an organic solvent, adjusting an pH value with an acid, and performing filtering anddrying to obtain the 2-methyl-6-nitrobenzoic acid. In a low-concentration nitric acid environment, 3-nitro-2-nitrobenzoic acid is produced and 2-methyl-6-nitrobenzoic acid is co-produced with oxygen used as an oxidizing agent, so the problems of low selectivity of 3-nitro-o-xylene in an oxidation process and high risks in a concentrated nitric acid oxidation process are solved.

2-methyl-3-methoxybenzoyl chloride synthesizing process

The invention discloses a 2-methyl-3-methoxybenzoyl chloride synthesizing process. According to the present invention, low-cost o-xylene is used as a starting raw material, the product is synthesizedby using a conventional synthesis method comprising nitrification, esterification, reduction, diazotization, methylation, acyl chlorination and other steps, and the total yield is controlled at more than 65%; the esterification of the intermediate product improves the separation degree of the intermediate; the reaction solvent is added in the diazotization step, such that the process parameters are relatively easy to control, and the purity of the intermediate in the diazotization step is more than 96% so as to provide the guarantee for the quality of the subsequent product; and with the synthesis process, the product quality is stable and reliable, and the cost is low.