88-51-7

Basic information

• Product Name: 2-Amino-4-chloro-5-methylbenzenesulfonic acid
• Synonyms: 2-Amino-4-Chloro-3-methylbenzenesulfonicacid;2-amino-4-chloro-5-methyl-benzenesulfonicaci;2-chloro-4-toluidine-5-sulfonicacid;2-chloro-p-toluidine-5-sulfonicacid;3-chloro-4-methylaniline-6-sulfonicacid;4-Amino-2-chlorotolulene-5-sulfonic;4-Chloro-5-methyl-2-aminobenzenesulfonicacid;6-amino-4-chloro-3-toluenesulfonicacid
• CAS NO: 88-51-7
• Molecular Formula: C₇H₈ClNO₃S
• Molecular Weight: 221.66
• EINECS: 201-837-6
• Product Categories: Intermediates of Dyes and Pigments;Intermediates;API Intermediate
• Mol File: 88-51-7.mol
• Article Data: 9

Chemical Properties

• Boiling Point: 163°C (rough estimate)
• Appearance: /
• Density: 1.3031 (rough estimate)
• Vapor Pressure: 0-0Pa at 25℃
• Refractive Index: 1.6210 (estimate)
• Storage Temp.: Keep in dark place,Inert atmosphere,Room temperature
• Solubility: Aqueous Acid (Slightly), DMSO (Slightly)
• PKA: -1.58±0.50(Predicted)
• CAS DataBase Reference: 2-Amino-4-chloro-5-methylbenzenesulfonic acid(CAS DataBase Reference)
• NIST Chemistry Reference: 2-Amino-4-chloro-5-methylbenzenesulfonic acid(88-51-7)
• EPA Substance Registry System: 2-Amino-4-chloro-5-methylbenzenesulfonic acid(88-51-7)

Safety Data

• Statements: 36/37/38
• Safety Statements: 26-36/37/39
• RIDADR: 3261
• RTECS: XT6330000
• HazardClass: 8
• PackingGroup: III
• Hazardous Substances Data: 88-51-7(Hazardous Substances Data)

Usage

Description

2-Amino-4-chloro-5-methylbenzenesulfonic acid is an organic compound characterized by the presence of an amino group, a chlorine atom, and a methyl group attached to a benzene ring, with a sulfonic acid group attached to the ring. This unique structure endows it with specific chemical properties that make it suitable for various applications.

Uses

Used in Agricultural Industry:
2-Amino-4-chloro-5-methylbenzenesulfonic acid is used as an intermediate in the method for preparing environment-friendly organic pigments for agricultural seed coating. Its incorporation into the pigment formulation contributes to the development of eco-friendly and sustainable seed coatings that can enhance seed performance and protect crops from various environmental stresses, thereby promoting agricultural productivity and sustainability.

InChI:InChI=1/C7H8ClNO3S/c1-4-2-7(13(10,11)12)6(9)3-5(4)8/h2-3H,9H2,1H3,(H,10,11,12)/p-1

Synthetic route

3-chloro-p-toluidine (95-74-9) → 6-amino-4-chloro-meta-toluenesulfonic acid (88-51-7)

Conditions	Yield
With sulfuric acid In 1,2-dichloro-benzene at 240℃; for 8h; Autoclave;	99.1%
With sulfuric acid In 1,2-dichloro-benzene at 240℃; for 8.5h; Temperature; Dean-Stark;	99.2%
durch Sulfurierung;

6-chloro-4-nitro-toluene-sulfonic acid-(3) → 6-amino-4-chloro-meta-toluenesulfonic acid (88-51-7)

thiophene (110-01-0) + sulfuric acid (7664-93-9) + 3-chloro-p-toluidine (95-74-9) → 6-amino-4-chloro-meta-toluenesulfonic acid (88-51-7)

2-picolinium 2-amino-4-chloro-5-methylbenzenesulfonate monohydrate → 6-amino-4-chloro-meta-toluenesulfonic acid (88-51-7)

Conditions	Yield
at 199.84℃;

quinolinium 2-amino-4-chloro-5-methylbenzenesulfonate quinoline → 6-amino-4-chloro-meta-toluenesulfonic acid (88-51-7)

Conditions	Yield
at 219.84℃;

bis(1-ammonio-3-chloro-4-methylbenzene)sulfate → 6-amino-4-chloro-meta-toluenesulfonic acid (88-51-7)

Conditions	Yield
at 239.84℃;

bis(1-ammonio-3-chloro-4-methylbenzene)sulfate → 6-amino-4-chloro-meta-toluenesulfonic acid (88-51-7) + 3-chloro-p-toluidine (95-74-9)

Conditions	Yield
Heating;

BARBITURIC ACID (67-52-7) + 6-amino-4-chloro-meta-toluenesulfonic acid (88-51-7) → C11H9ClN4O6S

Conditions	Yield
Stage #1: 6-amino-4-chloro-meta-toluenesulfonic acid With sulfuric acid; potassium hydroxide In water at 20℃; pH=1-2; Cooling with ice; Stage #2: With nitrosylsulfuric acid In water at 10℃; for 0.833333h; pH=1; Stage #3: BARBITURIC ACID With potassium hydroxide In water at 25 - 30℃; for 1h; pH=3;	98%
Stage #1: 6-amino-4-chloro-meta-toluenesulfonic acid With potassium hydroxide In water Stage #2: With nitrosylsulfuric acid; sulfuric acid In water at 10℃; for 0.833333h; pH=1; Stage #3: BARBITURIC ACID With potassium hydroxide In water at 25 - 30℃; for 1h; pH=2 - 3;

6-amino-4-chloro-meta-toluenesulfonic acid (88-51-7) + 3-Hydroxy-2-naphthoic acid (92-70-6) → Pigment Red 48

Conditions	Yield
Stage #1: 6-amino-4-chloro-meta-toluenesulfonic acid With hydrogenchloride; sodium hydroxide; sodium nitrite In water at 20.84℃; for 0.5h; Stage #2: 3-Hydroxy-2-naphthoic acid With aminosulfonic acid; sodium hydroxide In water for 2h;	95%

(fluorenylmethoxy)carbonyl chloride (28920-43-6) + 6-amino-4-chloro-meta-toluenesulfonic acid (88-51-7) → 4-chloro-2-(9H-fluoren-9-ylmethoxycarbonylamino)-5-methylbenzenesulfonic acid (895917-82-5)

Conditions	Yield
With sodium hydrogencarbonate In 1,4-dioxane; water	89%

6-amino-4-chloro-meta-toluenesulfonic acid (88-51-7) + 3-Bromophenyl isocyanate (23138-55-8) → 2-[3-(3-bromo-phenyl)-ureido]-4-chloro-5-methyl-benzenesulfonic acid (697278-42-5)

Conditions	Yield
With triethylamine In tetrahydrofuran at 20℃;	65%

6-amino-4-chloro-meta-toluenesulfonic acid (88-51-7) → 4-chloro-2-[3-(1H-indol-2-yl)-ureido]-5-methyl-benzenesulphonic acid (697278-51-6)

Conditions	Yield
Stage #1: Indole-2-carboxylic acid With diphenyl phosphoryl azide; triethylamine In toluene at 20℃; for 0.5h; Stage #2: 6-amino-4-chloro-meta-toluenesulfonic acid With triethylamine at 80℃; for 3h; Stage #3: With hydrogenchloride In water; ethyl acetate	53%

6-amino-4-chloro-meta-toluenesulfonic acid (88-51-7) → 2-amino-4-chloro-5-methyl benzenesulfonyl chloride (104613-64-1)

Conditions	Yield
With chlorosulphuric acid
Stage #1: 6-amino-4-chloro-meta-toluenesulfonic acid With sulfuryl dichloride In dichloromethane at 60℃; for 1h; Stage #2: With thionyl chloride In dichloromethane at 100℃; for 7h;	2.2 g
With chlorosulphuric acid

6-amino-4-chloro-meta-toluenesulfonic acid (88-51-7) → 4,6-dichloro-toluene-3-sulfonic acid

Conditions	Yield
ueber die Diazonium-Verbindung;

6-amino-4-chloro-meta-toluenesulfonic acid (88-51-7) → 2-chloro-5-sulfo-toluene-4-diazonium-betaine

Conditions	Yield
Diazotization;

6-amino-4-chloro-meta-toluenesulfonic acid (88-51-7) → 2-amino-4-chloro-5-methyl-benzenesulfonamide (55825-29-1)

Conditions	Yield
(i) ClSO3H, NaCl, (heating), (ii) aq. NH3; Multistep reaction;

6-amino-4-chloro-meta-toluenesulfonic acid (88-51-7) → 2-azido-4-chloro-5-methylbenzenesulfonic acid (871832-00-7)

Conditions	Yield
Stage #1: 6-amino-4-chloro-meta-toluenesulfonic acid With sulfuric acid; sodium nitrite In water at 0℃; for 0.5h; Stage #2: With sodium azide In water at 0 - 20℃; for 12h;

6-amino-4-chloro-meta-toluenesulfonic acid (88-51-7) → (S)-methyl 1-(2-amino-4-chloro-5-methylphenylsulfonyl)pyrrolidine-2-carboxylate (895917-83-6)

Conditions	Yield
Multi-step reaction with 2 steps 1.1: sulfuryl chloride / CH2Cl2 / 1 h / 60 °C 1.2: 2.2 g / thionyl chloride / CH2Cl2 / 7 h / 100 °C 2.1: 75 percent / pyridine / 4 h / 20 °C View Scheme

6-amino-4-chloro-meta-toluenesulfonic acid (88-51-7) → (S)-1-(2-Amino-4-chloro-5-methyl-benzenesulfonyl)-pyrrolidine-2-carboxylic acid

Conditions	Yield
Multi-step reaction with 3 steps 1.1: sulfuryl chloride / CH2Cl2 / 1 h / 60 °C 1.2: 2.2 g / thionyl chloride / CH2Cl2 / 7 h / 100 °C 2.1: 75 percent / pyridine / 4 h / 20 °C 3.1: 88 percent / aq. NaOH / ethanol View Scheme

6-amino-4-chloro-meta-toluenesulfonic acid (88-51-7) → 2-azido-4-chloro-5-methylbenzenesulfonamide (871832-22-3)

Conditions	Yield
Multi-step reaction with 3 steps 1.1: NaNO2; H2SO4 / H2O / 0.5 h / 0 °C 1.2: NaN3 / H2O / 12 h / 0 - 20 °C 2.1: oxalyl chloride / CH2Cl2; dimethylformamide / 3 h / Heating 3.1: 75 percent / NH3 / dioxane; CH2Cl2 / 3 h / 25 °C View Scheme

6-amino-4-chloro-meta-toluenesulfonic acid (88-51-7) → 2-azido-4-chloro-5-methyl-benzenesulfonyl chloride (871832-21-2)

Conditions	Yield
Multi-step reaction with 2 steps 1.1: NaNO2; H2SO4 / H2O / 0.5 h / 0 °C 1.2: NaN3 / H2O / 12 h / 0 - 20 °C 2.1: oxalyl chloride / CH2Cl2; dimethylformamide / 3 h / Heating View Scheme

6-amino-4-chloro-meta-toluenesulfonic acid (88-51-7) → 2-azido-4-chloro-N-(2-methoxyethyl)-5-methylbenzenesulfonamide (871832-04-1)

Conditions	Yield
Multi-step reaction with 3 steps 1.1: NaNO2; H2SO4 / H2O / 0.5 h / 0 °C 1.2: NaN3 / H2O / 12 h / 0 - 20 °C 2.1: oxalyl chloride / CH2Cl2; dimethylformamide / 3 h / Heating 3.1: ethyldiisopropylamine / CH2Cl2 / 6 h / 25 °C View Scheme

6-amino-4-chloro-meta-toluenesulfonic acid (88-51-7) → 3-n-butylamino-6-chloro-7-methyl-2H-1,2,4-benzothiadiazine 1,1-dioxide

Conditions	Yield
Multi-step reaction with 4 steps 1.1: NaNO2; H2SO4 / H2O / 0.5 h / 0 °C 1.2: NaN3 / H2O / 12 h / 0 - 20 °C 2.1: oxalyl chloride / CH2Cl2; dimethylformamide / 3 h / Heating 3.1: 75 percent / NH3 / dioxane; CH2Cl2 / 3 h / 25 °C 4.1: triphenylphosphine resin / CH2Cl2; tetrahydrofuran / 16 h / 25 °C 4.2: 55 percent / 1,2-dichloro-ethane; tetrahydrofuran / 24 h / 80 °C View Scheme

6-amino-4-chloro-meta-toluenesulfonic acid (88-51-7) → 6-chloro-7-methyl-3-(4-fluorophenylsulfonylamino)-2H-1,2,4-benzothiadiazine 1,1-dioxide

Conditions	Yield
Multi-step reaction with 4 steps 1.1: NaNO2; H2SO4 / H2O / 0.5 h / 0 °C 1.2: NaN3 / H2O / 12 h / 0 - 20 °C 2.1: oxalyl chloride / CH2Cl2; dimethylformamide / 3 h / Heating 3.1: 75 percent / NH3 / dioxane; CH2Cl2 / 3 h / 25 °C 4.1: triphenylphosphine resin / CH2Cl2; tetrahydrofuran / 16 h / 25 °C 4.2: 45 percent / 1,2-dichloro-ethane; tetrahydrofuran / 24 h / 80 °C View Scheme

6-amino-4-chloro-meta-toluenesulfonic acid (88-51-7) → 2-N-(2-methoxyethyl)-3-(3-fluoro-4-methylphenylamino)-6-chloro-7-methyl-2H-1,2,4-benzothiadiazine 1,1-dioxide

Conditions	Yield
Multi-step reaction with 4 steps 1.1: NaNO2; H2SO4 / H2O / 0.5 h / 0 °C 1.2: NaN3 / H2O / 12 h / 0 - 20 °C 2.1: oxalyl chloride / CH2Cl2; dimethylformamide / 3 h / Heating 3.1: ethyldiisopropylamine / CH2Cl2 / 6 h / 25 °C 4.1: triphenylphosphine resin / CH2Cl2 / 16 h / 25 °C 4.2: 45 percent / 1,2-dichloro-ethane / 24 h / 80 °C View Scheme

6-amino-4-chloro-meta-toluenesulfonic acid (88-51-7) → 2-N-(2-methoxyethyl)-3-(4-fluorophenylsulfonylamino)-6-chloro-7-methyl-2H-1,2,4-benzothiadiazine 1,1-dioxide

Conditions	Yield
Multi-step reaction with 4 steps 1.1: NaNO2; H2SO4 / H2O / 0.5 h / 0 °C 1.2: NaN3 / H2O / 12 h / 0 - 20 °C 2.1: oxalyl chloride / CH2Cl2; dimethylformamide / 3 h / Heating 3.1: ethyldiisopropylamine / CH2Cl2 / 6 h / 25 °C 4.1: triphenylphosphine resin / CH2Cl2 / 16 h / 25 °C 4.2: 80 percent / 1,2-dichloro-ethane / 24 h / 80 °C View Scheme

6-amino-4-chloro-meta-toluenesulfonic acid (88-51-7) → C7H6ClN2O3S(1+)*Cl(1-) (65151-15-7)

Conditions	Yield
With hydrogenchloride; sodium nitrite In water at 0 - 5℃; for 2h; Product distribution / selectivity;

6-amino-4-chloro-meta-toluenesulfonic acid (88-51-7) + 1-(3'-sulfophenyl)-3-methyl-5-pyrazolone (119-17-5) → Pigment Yellow 191 monohydrate

Conditions	Yield
Stage #1: 6-amino-4-chloro-meta-toluenesulfonic acid With hydrogenchloride; sodium nitrite Stage #2: 1-(3'-sulfophenyl)-3-methyl-5-pyrazolone With sodium hydroxide Stage #3: With water; calcium chloride at 80℃;

6-amino-4-chloro-meta-toluenesulfonic acid (88-51-7) + 3-Hydroxy-2-naphthoic acid (92-70-6) → 4-[(5-chloro-4-methyl-2-sulfophenyl)azo]-3-hydroxy-2-naphthoic acid (16013-44-8)

Conditions	Yield
Stage #1: 6-amino-4-chloro-meta-toluenesulfonic acid With sodium hydroxide In water Stage #2: With hydrogenchloride; sodium acetate; sodium nitrite In water at 10℃; pH=3 - 4; Stage #3: 3-Hydroxy-2-naphthoic acid In water at 15 - 60℃; for 3.5h;
Stage #1: 6-amino-4-chloro-meta-toluenesulfonic acid With hydrogenchloride; sodium nitrite In water at 0℃; for 1h; Stage #2: 3-Hydroxy-2-naphthoic acid With stearic acid; sodium hydroxide In water at 12℃; for 1.5h; Reagent/catalyst; Temperature;

6-amino-4-chloro-meta-toluenesulfonic acid (88-51-7) + 4-(4,5-dihydro-3-methyl-5-oxo-1H-pyrazol-1-yl)benzenesulfonic acid (89-36-1) → C17H13ClN4O7S2(2-)*Ca(2+)

Conditions	Yield
Stage #1: 6-amino-4-chloro-meta-toluenesulfonic acid; 4-(4,5-dihydro-3-methyl-5-oxo-1H-pyrazol-1-yl)benzenesulfonic acid With hydrogenchloride; sodium hydroxide; sodium nitrite In water at 40 - 80℃; pH=6 - 6.5; Stage #2: With calcium chloride In water at 80℃; for 2h;

6-amino-4-chloro-meta-toluenesulfonic acid (88-51-7) + 4-(4,5-dihydro-3-methyl-5-oxo-1H-pyrazol-1-yl)benzenesulfonic acid (89-36-1) → C17H13ClN4O7S2(2-)*Sr(2+)

Conditions	Yield
Stage #1: 6-amino-4-chloro-meta-toluenesulfonic acid; 4-(4,5-dihydro-3-methyl-5-oxo-1H-pyrazol-1-yl)benzenesulfonic acid With hydrogenchloride; sodium hydroxide; sodium nitrite In water at 40 - 80℃; pH=6 - 6.5; Stage #2: With strontium chloride In water at 80℃; for 2h;

Upstream product

• 95-74-9 3-chloro-p-toluidine 
• 110-01-0 thiophene 
• 7664-93-9 sulfuric acid 

Downstream Products

• 895917-82-5 4-chloro-2-(9H-fluoren-9-ylmethoxycarbonylamino)-5-methylbenzenesulfonic acid 
• 95-74-9 3-chloro-p-toluidine 
• 16013-44-8 4-[(5-chloro-4-methyl-2-sulfophenyl)azo]-3-hydroxy-2-naphthoic acid 
• 65151-15-7 C₇H₆ClN₂O₃S⁽¹⁺⁾*Cl^(1-) 
• 697278-51-6 4-chloro-2-[3-(1H-indol-2-yl)-ureido]-5-methyl-benzenesulphonic acid 
• 871832-04-1 2-azido-4-chloro-N-(2-methoxyethyl)-5-methylbenzenesulfonamide 
• 871832-21-2 2-azido-4-chloro-5-methyl-benzenesulfonyl chloride 
• 871832-22-3 2-azido-4-chloro-5-methylbenzenesulfonamide 
• 895917-83-6 (S)-methyl 1-(2-amino-4-chloro-5-methylphenylsulfonyl)pyrrolidine-2-carboxylate 
• 871832-00-7 2-azido-4-chloro-5-methylbenzenesulfonic acid 

Relevant articles and documents

ECO-FRIENDLY METHOD FOR PREPARING HIGHLY PURE 2-CHLORO-4-AMINOTOLUENE-5-SULFONIC ACID

The present invention relates to an eco-friendly method for preparing highly pure 2-chloro-4-aminotoluene-5-sulfonic acid, which includes efficient reaction processes to provide highly pure 2-chloro-4-aminotoluene-5-sulfonic acid without a purification process, and minimizes generation of contaminants by reusing a waste solvent after distillation. The method comprises the steps of: 1) adding 2-chloro-4-aminotoluene, a solvent and sulfuric acid to a reactor; 2) carrying out sulfonation of the reaction materials added to the reactor; 3) filtering and washing the compound produced from the step 2) with a solvent to provide wet cake; 4) vacuum drying the wet cake obtained from the step 3) to provide 2-chloro-4-aminotoluene-5-sulfonic acid; and 5) carrying out distillation of the waste solvent generated from the steps 3) and 4).(AA) Start(BB) End(S10) Add 2-chloro-4-aminotoluene, solvent and sulfuric acid to a reactor(S20) Carry out sulfonation on additive added to the reactor(S30) Filter and wash compound subjected to sulfonation with solvent to obtain wet cake(S40) Vacuum dry wet cake to obtain 2-chloro-4-aminotoluene-5-sulfonic acid(S50) Carry out distillation of waste solvent generated during filtering, washing and vacuum dryingCOPYRIGHT KIPO 2016

The influence of different solvents on 2-ammonio-4-chloro-5- methylbenzenesulfonate, including its De- and resulfonation

The title compound (2-ammonio-4-chloro-5-methylbenzenesulfonate), C 7H8ClNO3S, 1, is an intermediate in the synthesis of laked red and yellow azo pigments. Heating 1 in 2-picoline, quinoline and N,N′-dimethylacetamide (DMAc) [or N-methyl-2-pyrrolidone (NMP)] resulted in the formation of three different compounds: a 2-picolinium hydrate (2), a quinolinium quinoline solvate (3), and a sulfate of the desulfonated title compound (4). The three new compounds were structurally characterised using single-crystal diffraction data and chemically using thermal analysis (DTA/TGA), elemental analysis and spectroscopic methods (IR and NMR). By heating 2, 3 and 4 in the solid state, compound 1 is obtained again. In the case of 4, this corresponds to a desulfonation-resulfonation reaction in subsequent steps, which is rarely observed as such. Graphical Abstract: The title compound 2-ammonio-4-chloro-5-methylbenzenesulfonate was heated in 2-picoline, quinoline and N,N′-dimethylacetamide (DMAc) resulting in the formation of three different compounds: a 2-picolinium hydrate (2), a quinolinium quinoline solvate (3), and a sulfate of the desulfonated title compound (4 see Figure). Heating 2, 3 and 4 in the solid state, compound 1 is obtained again. In the case of 4, this corresponds to a desulfonation- resulfonation reaction in subsequent steps, which is rarely observed as such.[Figure not available: see fulltext.]

Mixed coupled azo pigments

(1) A mixed coupled azo pigment prepared from: (A) 30% to 70% of two or more diazonium components, at least one derived from a monoaryl amine and (B) an organic coupling component, said pigment containing one or more COOH or SO H groups or esters, amides, alkali metal or alkali earth metal salts thereof or (2) A mixed coupled azo pigment prepared from: (A) 5% to 95% of two or more bis, tris or tetrakis diazonium components, at least one derived from a monoaryl amine and meeting certain specific critria and (B) an organic coupling component, said pigment comprising the same acid or salt groups of pigment (1).