PRODUCTS

O-PHENYLENEDIAMINE

o-Phenylenediamine also serves as a starting material for producing benzotriazoles, quinoxalines, phenazines, and numerous nitrogen-containing heterocycles.
o-Phenylenediamine is used as an intermediate in the manufacture of dyes, pigments, andfungicides.
o-Phenylenediamine is also used in hair dye formulation, as a photographic developing agent,and in organic synthesis.

CAS Number: 95-54-5
EC Number: 202-430-6
Molecular Formula: C₆H₈N₂
Molecular Weight: 108.14 g/mol

SYNONYMS:
o-Phenylenediamine, ortho-Phenylenediamine, 1,2-Phenylenediamine, 1,2-Benzenediamine, Benzene-1,2-diamine, o-Benzenediamine, OPD, OPDA, 2-Aminoaniline, 1,2-Diaminobenzene, Catechol diamine, NSC 5144, UNII-6U6W3X0X53, o-phenylenediamine phenylene-1,2-dimaine CI oxidation base 16 PODA 2-phenylene diamine ccris 508 o-fenylendiamin C.I. oxidation base 16 1,2-fenylendiamin orthamine, Benzene-1,2-diamine, o-Phenylene diamine, 1,2-Diaminobenzene, 1,2-Phenylenediamine, O-PHENYLENEDIAMINE, benzene-1,2-diamine, 95-54-5, 1,2-Phenylenediamine, 1,2-Diaminobenzene, 2-Aminoaniline, 1,2-Benzenediamine, o-Diaminobenzene, Orthamine, o-Benzenediamine, PODA, ortho-Phenylenediamine, C.I. Oxidation Base 16, 2-Phenylene diamine, o-Aminoaniline, EK 1700, SQ 15500, CI Oxidation Base 16, C.I. 76010, NSC 5354, DTXSID3025881, CI 76010, orthophenylenediamine, 8B713N8Q0F, NSC-5354, O-AMINOPHENYLAMINE, DTXCID905881, CHEBI:34043, RefChem:6077, 202-430-6, OPDA, o-Phenylene diamine, o-Fenylendiamin, IK 3, 1,2-Fenylendiamin, MFCD00007721, phenylene-1,2-dimaine, Lansoprazole Impurity 22, NSC5354, aniline, 2-amino-, NCGC00090885-03, o-Fenylendiamin [Czech], 1,2-Fenylendiamin [Czech], CCRIS 508, HSDB 2893, Phenylenediamine, ortho-, EINECS 202-430-6, BRN 0606074, UNII-8B713N8Q0F, o-phenylendiamin, AI3-24343, o-phenylendiamine, Phenylene diamine, 2-Amino-aniline, ortho-aminoaniline, 0-phenylendiamine, 0-phenylenediamine, 2-aminophenylamine, o-phenyl-enediamine, o-phenyle-nediamine, o-phenylene-diamine, Phenylenediamine, o-, and its salt, 1.2-diaminobenzene, 1,2-phenylendiamine, 1,2 phenylenediamine, 1,2-benzenedi-amine, 1.2-phenylenediamine, ortho phenylene diamine, (2-aminophenyl)-amine, 1,2-phenylene diamine, 1,2-phenylene-diamine, WLN: ZR BZ, EC 202-430-6, NCIMech_000739, SCHEMBL6187, SCHEMBL19022, 1,2-DIAMINO-BENZENE, 4-13-00-00038 (Beilstein Handbook Reference), BIDD:ER0680, CHEMBL70582, SCHEMBL295682, SCHEMBL387162, SCHEMBL2071495, SCHEMBL3956262, SCHEMBL8740047, O-PHENYLENEDIAMINE [MI], SCHEMBL11062175, SCHEMBL15511951, SCHEMBL29351116, O-PHENYLENEDIAMINE [HSDB], STR03001, Tox21_400014, CCG-35856, EBC-47562, MSK000851, o-Phenylenediamine, flaked, 99.5%, SBB040801, STK301816, AKOS000119133, o-Phenylenediamine, sublimed, >=99%, AT28018, FP26951, MSK000851-100A, CAS-95-54-5, MSK000851-1000A, NCGC00090885-01, NCGC00090885-02, NCGC00090885-04, NCGC00090885-05, NCGC00090885-06, BP-11855, NCI60_004318, PD011925, 2-Phenylene diamine (1,2Phenylenediamine), NS00006526, P0168, P0968, P1805, ST45061692, TIABENDAZOLE IMPURITY A [EP IMPURITY], EN300-19093, o-Phenylenediamine, for fluorescence, free base, AC-907/25014349, F094521, Lansoprazole Impurity 6; Tiabendazole EP Impurity A, Q3596763, o-Phenylenediamine [UN1673] [Keep away from food], o-Phenylenediamine Solution in Acetonitrile, 100ug/mL, o-Phenylenediamine Solution in Acetonitrile, 1000ug/mL, o-Phenylenediamine, tablet, 20 mg substrate per tablet, Z104472742, o-Phenylenediamine, Peroxidase substrate, >=98.0%, powder, o-Phenylenediamine, suitable for fluorescence, >=99.0% (NT), InChI=1/C6H8N2/c7-5-3-1-2-4-6(5)8/h1-4H,7-8H, 25667-98-5, 1,2-Diaminobenzene, 1,2-Phenylenediamine, OPD, OPD, 2-aminoaniline, o-benzenediamine, 1,2-benzenediamine, CI oxidation base 16, CI 76010, O-diaminobenzene, 1,2-diaminobenzene, EK 1700, NSC 5354, Orthamine, 1,2-phenylenediamine, SQ 15500, benzene-1,2-diamine, OPDA, Phenylenediamine, OPD, 1,2-PHENYLENEDIAMINE, 1,2-DIAMINOBENZENE, 1,2-BENZENEDIAMINE, PODA, ORTHO-TOLUENEDIAMINE, orthamine

o-phenylenediamine (aka 1,2-diaminobenzene) is an aromatic diamine, characterized by two amino (NH2) groups attached to a benzene ring.
Compare o-Phenylenediamine's chemical structures to its two isomers, m-phenylenediamine and p-phenylenediamine.
o-Phenylenediamine is a colorless monoclinic crystals if pure; technical grade brownish-yellow crystals or a sandy brown solid.

o-phenylenediamine has active chemical properties, being able to have condensation reaction with acid, aldehydes, ketones and other compounds, generating heterocyclic compounds; it can also have oxidation, condensation, substitution and diazotization reaction.
o-phenylenediamine is actively involved in the preparation of pharmaceuticals by reacting substituted o-phenylenediamine with various diketones.

o-Phenylenediamine (OPD) is an organic compound with the formula C6H4(NH2)2.
This aromatic diamine, o-Phenylenediamine, is an important precursor to many heterocyclic compounds.
o-Phenylenediamine is a white compound although samples appear darker owing to oxidation by air.

o-Phenylenediamine is isomeric with m-phenylenediamine and p-phenylenediamine.
o-Phenylenediamine appears as colorless monoclinic crystals if pure; technical grade brownish-yellow crystals or a sandy brown solid.
o-Phenylenediamine is used in manufacture of dyes, photography, organic synthesis.

o-Phenylenediamine is a phenylenediamine in which the two amino groups are ortho to each other.
o-Phenylenediamine is a hydrogen donor and a phenylenediamine.
o-Phenylenediamine derives from a hydride of a benzene.

o-Phenylenediamine (OPD), also known as 1,2-benzenediamine, is an aromatic diamine containing two primary amino groups attached to adjacent carbon atoms on a benzene ring.
The presence of two highly reactive amino groups makes o-Phenylenediamine an important intermediate in the synthesis of heterocyclic compounds, pharmaceuticals, dyes, pigments, antioxidants, corrosion inhibitors, polymers, and specialty chemicals.

o-Phenylenediamine is particularly valuable as a precursor for the production of benzimidazoles, benzotriazoles, quinoxalines, and phenazine derivatives, many of which exhibit significant biological and industrial properties.
Although o-Phenylenediamine is generally colorless to pale brown, prolonged exposure to air and light causes gradual oxidation and darkening due to the formation of colored oxidation products.

Phenylenediamine is the simplest aromatic diamine.
There are three isomers, namely o-phenylenediamine, m-phenylenediamine and p-phenylenediamine.
p-Phenylenediamine appears as a colorless crystal, being quickly oxidized in the air into black.

o-Phenylenediamine has a boiling point of 267 °C.
o-Phenylenediamine is soluble in water, ethanol and ether.
o-Phenylenediamine can be used as raw materials or intermediates of dyes, vulcanization accelerators for rubber, developers for the photographic industry, fur dyes and hair dyes.

O-phenylenediamine is also known as 1, 2-diaminobenzene, 1, 2-phenylenediamine.
o-Phenylenediamine precipitated from the water appears as white to pale yellow leaf-like crystals while product precipitated from chloroform appears as prism-like crystals.
o-Phenylenediamine's color is easy to change upon exposure to air, from white to yellow, brown, purple, and finally into black.

o-Phenylenediamine has a relative density of 1.2698, the melting point of 103 °C to 104 °C, the boiling point of 256~258 °C.
o-Phenylenediamine is slightly soluble in cold water (35 °C 4.15), being easily soluble in hot water (81 °C, 733), ethanol, ether, chloroform and benzene.

o-Phenylenediamine's reaction with inorganic acid can lead to the formation of water-soluble salts; its aqueous solution can react with carbon disulfide to generate 2-mercapto-benzimidazole; under pressure, it can react with carbon dioxide reaction to generate benzimidazolone.
o-Phenylenediamine is an organic compound with the formula C6H4(NH2)2.
This aromatic diamine, o-Phenylenediamine, is an important precursor to many heterocyclic compounds.

USES and APPLICATIONS of O-PHENYLENEDIAMINE:
o-Phenylenediamine is one of the most important organic synthesis intermediates used in the manufacture of pharmaceuticals, dyes, pigments, agrochemicals, rubber chemicals, corrosion inhibitors, antioxidants, photographic chemicals, and specialty materials.
o-Phenylenediamine's principal industrial application is the synthesis of benzimidazole derivatives, which are widely used as pharmaceutical intermediates, fungicides, veterinary medicines, proton pump inhibitors, antiviral agents, and biologically active heterocyclic compounds.

o-Phenylenediamine is an amino-substituted benzene used in the manufacture of dyes.
In the dye industry, o-phenylenediamine is used in the production of oxidation hair dyes, azo dyes, sulfur dyes, textile dyes, leather colorants, photographic developers, and specialty pigments.

The presence of two amino groups enables rapid coupling and condensation reactions required for color formation.
o-Phenylenediamine is also employed in the manufacture of rubber antioxidants, polymer stabilizers, epoxy curing agents, corrosion inhibitors, ultraviolet absorbers, and specialty resins.
In analytical chemistry and biotechnology, o-phenylenediamine is widely used as a chromogenic substrate in enzyme-linked immunosorbent assays (ELISA), particularly for horseradish peroxidase (HRP)-based detection systems, where it produces a colored reaction product suitable for spectrophotometric measurement.

o-Phenylenediamine is used to detect horseradish peroxidase activity.
Research laboratories extensively utilize o-phenylenediamine in synthetic organic chemistry for cyclization reactions, heterocyclic synthesis, catalyst development, medicinal chemistry, and coordination chemistry involving transition metal complexes.

o-Phenylenediamine is widely used in organic synthesis because it readily undergoes condensation, cyclization, oxidation, diazotization, and substitution reactions.
o-Phenylenediamine is used in manufacture of dyes, photography, organic synthesis.
o-Phenylenediamine can be used as a cationic dye intermediates, being the main raw material of pesticides, carbendazim and other fungicides.

o-Phenylenediamine can be used as analytical reagent, fluorescent indicator, also used in organic and dye synthesis.
o-Phenylenediamine can be used as pesticides, pharmaceuticals and dyes intermediates.
o-Phenylenediamine is used as a pesticide intermediates, dye intermediates.

In addition, o-Phenylenediamine can also used as an important intermediate of dye industry.
o-Phenylenediamine is a versatile aromatic amine known for its significant role in various industrial applications and research fields.
o-Phenylenediamine, also recognized as 1,2-diaminobenzene, is primarily utilized in the production of dyes, particularly in the textile industry, where it serves as a key intermediate in synthesizing azo dyes.

Its ability to form stable complexes with metals makes o-Phenylenediamine valuable in the development of pigments and colorants.
Additionally, o-Phenylenediamine is employed in the manufacture of rubber antioxidants, enhancing the durability and longevity of rubber products.
In the realm of research, o-Phenylenediamine is frequently used in biochemical assays and as a reagent in organic synthesis, particularly in the preparation of various heterocyclic compounds.

o-Phenylenediamine's unique properties, such as its reactivity and ability to participate in electrophilic substitution reactions, make it an essential tool for chemists.
With its broad applicability and essential role in enhancing product performance, o-Phenylenediamine stands out as a crucial compound for professionals in the chemical and manufacturing sectors.

o-Phenylenediamine can be used in the manufacture of polyamide, polyurethane, fungicides carbendazim and thiophanate, reduction scarlet GG, leveling agent, antioxidant MB, also used in the preparation of the developer, surfactant and so on.
o-Phenylenediamine can be used as intermediates of chemical raw materials, pesticides and dyes.

o-Phenylenediamine is primarily used in the production of fungicides (such as carbendazim, benomyl, methyl thiophanate, and thiabendazole), reduction dyes (such as reduction yellow 6GD and reduction brilliant orange GR), cationic dyes (such as cationic brilliant yellow 10GFF), polymer stabilizers (such as 2-mercaptobenzimidazole), heterocyclic compounds (such as benzimidazole and quinoxaline), photosensitive materials, surfactants, antifreeze agents, and copper corrosion inhibitors.

o-Phenylenediamine is also one of the components in hair dye formulations and a commonly used organic reagent for the identification of 1,2-diketones, carboxylic acids, and aldehydes in analytical chemistry.
o-Phenylenediamine can be used as an intermediate in the production of pesticides and dyes, and is used to produce fur brown M, cationic dyes, and reduction scarlet GG.
o-Phenylenediamine is used to detect horseradish peroxidase activity.

o-Phenylenediamine functions as a primary intermediate in the production of various dyes, pigments, and polymers.
o-Phenylenediamine acts as a precursor for the synthesis of hair dyes, textile dyes, and rubber antioxidants.
o-Phenylenediamine is utilized for its ability to undergo oxidative coupling reactions to form heterocyclic compounds.

o-Phenylenediamine is a building block in the formation of polybenzimidazoles, which are high-performance polymers with exceptional thermal and chemical stability.
At the molecular level, o-Phenylenediamine participates in electrophilic aromatic substitution reactions, enabling the formation of complex organic molecules with diverse applications in materials science and industrial chemistry.

o-phenylenediamine is used to prepare tiabendazole, pyrazinamide, morinamide, clemizole and chlormidazole.
o-Phenylenediamine is involved in the synthesis of benzimidazole by reacting with carboxylic acids and their derivatives.
o-Phenylenediamine is also used to prepare quinoxalinedione and mercaptoimidazoles by condensation with dimethyl oxalate and xanthate esters respectively.

o-Phenylenediamine reacts with nitrous acid to get benzotriazole, which finds application as a corrosion inhibitor.
It is actively involved in the preparation of pharmaceuticals by reacting substituted o-phenylenediamine with various diketones.
o-phenylenediamine is used to prepare tiabendazole, pyrazinamide, morinamide, clemizole and chlormidazole.
o-Phenylenediamine is involved in the synthesis of benzimidazole by reacting with carboxylic acids and their derivatives.

o-Phenylenediamine is also used to prepare quinoxalinedione and mercaptoimidazoles by condensation with dimethyl oxalate and xanthate esters respectively.
o-Phenylenediamine reacts with nitrous acid to get benzotriazole, which finds application as a corrosion inhibitor.
It is actively involved in the preparation of pharmaceuticals by reacting substituted o-phenylenediamine with various diketones.

-Printing and dyeing industry use of o-Phenylenediamine:
o-phenylenediamine is mainly used in the manufacture of pesticides fungicides (carbendazim, benomyl, thiophanate-methyl, Thiabendazole), reducing dyes (reduction Yellow 6GD, reduction brilliant orange GR), cationic dye (Cationic brilliant yellow 10GFF), polymer stabilizer (2-mercaptobenzimidazole), heterocyclic compounds (benzimidazole and quinoxaline), photographic materials, surfactants, antifreeze, copper anticorrosive.
o-Phenylenediamine is one of the components of the hair dye formulation and is one of the organic reagents commonly used in analytical chemistry to identify 1, 2-diesters, carboxylic acids and aldehydes.

-o-Phenylenediamine can be used:
To prepare quinoxalines, benzimidazoles, and 1H-1,5-benzodiazepines by condensing with aryl aldehydes or ketones.
In the H2O mediated one-pot preparation of 1,2-disubstituted benzimidazoles by reacting with aldehydes in the presence of trimethylsilyl chloride.
In the copper-catalyzed synthesis of alkyne substituted quinoxalines by reacting with terminal alkynes.
In the preparation of 1,5-benzodiazepine derivatives by reacting with different ketones under neat reaction conditions via ytterbium trichloride catalyzed condensation reaction.

WHAT IS O-PHENYLENEDIAMINE and hOW IS O-PHENYLENEDIAMINE USED?
o-Phenylenediamine, also known as 1,2-phenylenediamine, has the molecular formula C6H8N2.
o-Phenylenediamine is a white to red crystalline substance that darkens in color when exposed to air and sunlight.
o-Phenylenediamine has a melting point of 103-104℃ and a boiling point of 256-258℃.

o-Phenylenediamine is slightly soluble in cold water, more soluble in hot water, and easily soluble in ethanol, ether, and chloroform.
o-Phenylenediamine reacts with inorganic acids to form water-soluble salts.
o-Phenylenediamine is used in the production of pesticides, dyes, surfactants, and fur dyes.
o-Phenylenediamine can be synthesized from ortho-dinitrobenzene through reduction or from ortho-nitrochlorobenzene through amination and reduction.

BENEFITS and CHARACTERISTICS of O-PHENYLENEDIAMINE:
o-Phenylenediamine possesses two adjacent amino groups that provide exceptionally high chemical reactivity and synthetic versatility.
This unique molecular arrangement enables efficient cyclization reactions leading to valuable heterocyclic compounds that are difficult to prepare by alternative synthetic routes.

o-Phenylenediamine readily undergoes condensation, oxidation, reduction, diazotization, electrophilic substitution, nucleophilic substitution, and metal-complex formation, making it one of the most versatile aromatic diamines available for industrial and laboratory synthesis.
o-Phenylenediamine's relatively low molecular weight and high chemical reactivity allow efficient conversion into high-value products with excellent reaction yields.
The adjacent amino groups facilitate rapid ring-closure reactions that produce benzimidazoles, quinoxalines, and benzotriazoles under relatively mild conditions.

o-Phenylenediamine demonstrates good compatibility with numerous organic solvents and reaction systems, making it suitable for both laboratory-scale research and large-scale industrial production.
o-Phenylenediamine is commercially available in high purity and is widely recognized as an essential building block in pharmaceutical chemistry, materials science, and fine chemical manufacturing.

o-Phenylenediamine's usefulness as a chromogenic substrate in immunoassays further extends its applications beyond chemical manufacturing into biotechnology, clinical diagnostics, and biochemical research.

PREPARATION of O-PHENYLENEDIAMINE:
Commonly, 2-nitrochlorobenzene is treated with ammonia to generate 2-nitroaniline, whose nitro group is then reduced:
ClC6H4NO2 + 2 NH3 → H2NC6H4NO2 + NH4Cl
H2NC6H4NO2 + 3 H2 → H2NC6H4NH2 + 2 H2O
In the laboratory, the reduction of the nitroaniline is effected with zinc powder in ethanol, followed by purification of the diamine as the hydrochloride salt.
Darkened impure samples can be purified by treatment of its aqueous solution with sodium dithionite and activated carbon.

REACTIONS AND USES of O-PHENYLENEDIAMINE:
o-Phenylenediamine condenses with ketones and aldehydes to give rise to various valuable products.
o-Phenylenediamine's reactions with formic acids to produce benzimidazole.
Other carboxylic acids give 2-substituted benzimidazoles.

The herbicides benomyl and fuberidazole are made in this manner.
Thiophanate-methyl is another herbicide produced from o-phenylenediamine.
Condensation with potassium ethylxanthate gives 2-mercaptobenzimidazole.

With nitrous acid, o-phenylenediamine condenses to give benzotriazole, a corrosion inhibitor.
Quinoxalinedione may be prepared by condensation of o-phenylenediamine with dimethyl oxalate.
Mercaptoimidazole are commonly used as antioxidants in rubber production, obtained by condensing xanthate esters.

Condensation of substituted o-phenylenediamine with diketones yields various pharmaceuticals.
o-Phenylenediamine is a ligand in coordination chemistry.

Oxidation of metal-phenylenediamine complexes affords the diimine derivatives.
o-Phenylenediamine condenses with salicylaldehyde to give chelating Schiff base ligands.
o-Phenylenediamine reacts with thionyl chloride to give 2,1,3-benzothiadiazole: C6H4(NH2)2 + 2 SOCl2 → C6H4(N)2S + SO2 + 4HCl

HOW IS O-PHENYLENEDIAMINE PREPARED?
Reduction of ortho-nitroaniline with sodium sulfide
The reaction between ortho-nitroaniline and sodium sulfide solution is carried out at a pressure of 98-196 kPa and a reaction temperature of 105-110°C.
It can also be conducted at a reaction temperature of 120-130°C and atmospheric pressure.
The reaction time is 3-4 hours, resulting in o-Phenylenediamine.

Hydrogenation of ortho-nitroaniline
Using ortho-nitroaniline as the raw material and Raney nickel as the catalyst, the reaction is carried out in a high-pressure reactor at a controlled temperature of 95-105°C.
Hydrogen gas is continuously supplied until the pressure no longer decreases, and the product is obtained under a pressure of 1.960 MPa with stirring.
Among the two preparation methods mentioned above, the sodium sulfide reduction method yields a higher purity product and has a more mature process route.

Many domestic factories use this method to produce o-Phenylenediamine.
However, this method has poor labor protection conditions and generates a large amount of wastewater.
The catalytic hydrogenation method still has some issues in the process and requires further improvement for industrialization.
In addition, there is also the method of amination of ortho-dichlorobenzene, which has been studied by many domestic units but has not been industrialized yet.

CHEMICAL PROPERTIES of O-PHENYLENEDIAMINE:
o-Phenylenediamine appears as colorless monoclinic crystal with air and sunlight in the darker.
o-Phenylenediamine is slightly soluble in cold water, being more soluble in hot water, soluble in alcohol, ether and chloroform.
o-Phenylenediamine is a white to off white solid
o-Phenylenediamine is a white to brownish crystalline substance that turns red upon exposure to air.

AIR & WATER REACTIONS of O-PHENYLENEDIAMINE:
o-Phenylenediamine is soluble in water.
Melting point of o-Phenylenediamine is 219 F.
Flash point of o-Phenylenediamine is 277 F.

REACTIVITY PROFILE of O-PHENYLENEDIAMINE:
o-Phenylenediamine, a weak aromatic amine base, neutralizes acids in exothermic reactions to form salts.
o-Phenylenediamine may be incompatible with isocyanates, halogenated organics, peroxides, phenols (acidic), epoxides, anhydrides, and acid halides.
o-Phenylenediamine darkens on exposure to air.

PRODUCTION METHODS of O-PHENYLENEDIAMINE:
Take o-nitroaniline as raw materials, use sodium sulfide reduction or catalytic hydrogenation for reduction of o-phenylenediamine.
Addition of 21% sodium sulfide solution and o-nitroaniline into the reducing pot, raising the temperature to 90 °C, close and raise the temperature to 105-110 °C and increase the pressure to 0.1-0.2 MPa, stirring and reducing for 5 h, cooling to below 40 °C, filter.

The filter cake is heated and melted, vacuum distillation, collecting the fraction in 140-210 °C (7.89kPa), namely o-phenylenediamine with the yield of 70-80%.
The hydrogenation process should proceed in the autoclave with the reaction temperature of 95-105 °C with the pressure of about 2MPa.
It should be subject to hydrogenation reaction under the action of nickel catalyst for about 1h until the hydrogen pressure does not decline.

The yield of o-phenylenediamine was above 97%.
There are several preparation methods as follows.

O-Nitroaniline and Sodium Sulfide Reduction
Its reaction with o-nitroaniline and sodium sulfide solution at a pressure of 98 to 196 kPa and a reaction temperature of 105 to 110 ° C, being also carried out at a reaction temperature of 120 to 130 °C under atmospheric pressure for 3 to 4 hours to obtain o-benzenediamine amine.

O-nitroaniline: hydrogenation reduction method
Use o-nitroaniline as the raw material and Raney nickel as the catalyst, the reaction temperature was raised from 95 to 105 ° C in the autoclave, and the product was obtained by stirring at 1.960 MPa under continuous pressure of hydrogen gas until the pressure did not drop.

For the above two preparation methods, the sodium sulfide reduction method can obtain the product of high purity with relative mature process.
There are more factories in the domestic production of o-phenylenediamine.

But the method has poor labor protection conditions with much wastewater.
There are still some problems in the catalytic hydrogenation with industrialization needs to be further improved.
In addition, there is also o-dichlorobenzene ammonia solution, there are more units have been studied, but not yet industrialized.

SOLUBILITY of O-PHENYLENEDIAMINE:
o-Phenylenediamine is soluble in alcohol, chloroform, ether, slightly soluble in water.
o-Phenylenediamine is soluble in hot water.

NOTES of O-PHENYLENEDIAMINE:
o-Phenylenediamine is moisture- and air-sensitive.
Keep o-Phenylenediamine tightly closed in a dry and well-ventilated place.
o-Phenylenediamine is incompatible with strong oxidizing agents.

OCCURRENCE/USE of O-PHENYLENEDIAMINE:
Chemical intermediate in synthesis of fungicides, corrosion inhibitors, pigments, and pharmaceuticals; analytical reagent; remove elemental sulfur in mining ores and aldehyde color formers in polymeric producs.

PHYSICAL and CHEMICAL PROPERTIES of O-PHENYLENEDIAMINE:
Appearance: White, off-white, pale beige, or light brown crystalline solid; darkens upon exposure to air and light.
Odor: Slight aromatic amine-like odor.
Physical State: Crystalline solid.
Molecular Formula: C₆H₈N₂.
Molecular Weight: 108.14 g/mol.
Density: Approximately 1.27 g/cm³ at 20°C.
Melting Point: Approximately 101–104°C.
Boiling Point: Approximately 252–258°C (with partial decomposition).
Flash Point: Approximately 110–120°C.
Auto-ignition Temperature: Approximately 580°C.

Vapor Pressure: Very low at room temperature.
Water Solubility: Moderately soluble in water.
Solubility: Soluble in ethanol, methanol, acetone, ether, chloroform, dilute acids, and many polar organic solvents.
pKa: Approximately 4.5–4.7 (conjugate acid).
Partition Coefficient (log Kow): Approximately 0.1–0.3.
Refractive Index: Not generally applicable (solid).
Chemical Nature: Aromatic diamine.
Functional Groups: Two primary aromatic amino groups.

Hygroscopicity: Slightly hygroscopic.
Stability: Stable under recommended storage conditions but gradually oxidizes in air.
Air Sensitivity: Readily oxidized by atmospheric oxygen.
Light Sensitivity: Prolonged exposure causes discoloration.
Oxidation Behavior: Easily oxidized to colored quinonoid compounds and polymeric oxidation products.
Reducing Ability: Moderate reducing agent.
Reactivity: Reacts readily with aldehydes, ketones, acid chlorides, carboxylic acids, oxidizing agents, nitrites, and diazonium compounds.
Acid-Base Behavior: Weak organic base.
Thermal Stability: Stable under normal temperatures; decomposes upon excessive heating.

Dust Hazard: Fine dust may form combustible dust-air mixtures.
Decomposition Products: Carbon monoxide, carbon dioxide, nitrogen oxides, ammonia, and aromatic amine derivatives.
Chemical Name: o-Phenylenediamine
Other Name: 1,2-Benzenediamine
IUPAC Name: Benzene-1,2-diamine
CAS Number: 95-54-5
EC Number: 202-430-6
Molecular Formula: C₆H₈N₂
Molecular Weight: 108.14 g/mol
Empirical Formula (Hill Notation): C₆H₈N₂

Molecular Weight: 108.14
UNSPSC Code: 12352100
NACRES: NA.22
PubChem Substance ID: 24898319
Beilstein/REAXYS Number: 606074
MDL Number: MFCD00007721
Assay: 99.5%
Form: Powder
Appearance (Color): White to pale brown

Assay (GC): ≥97.5%
Melting Point (clear melt): 99-104 °C
Form: Crystals, flakes or pellets
Identification (FTIR): Conforms
Comment: May darken on storage
InChI Key: GEYOCULIXLDCMW-UHFFFAOYSA-N
SMILES: NC1=CC=CC=C1N
Molar Mass: 108.144 g/mol
Appearance: White solid
Density: 1.031 g/cm³
Melting Point: 102 to 104 °C

Boiling Point: 252 °C
Solubility in Water: Soluble in hot water
Magnetic Susceptibility: −71.98·10⁻⁶ cm³/mol
XLogP3: 0.1
Hydrogen Bond Donor Count: 2
Hydrogen Bond Acceptor Count: 2
Rotatable Bond Count: 0
Exact Mass: 108.068748264 Da
Monoisotopic Mass: 108.068748264 Da
Topological Polar Surface Area: 52 Å²

Heavy Atom Count: 8
Formal Charge: 0
Complexity: 62.9
Isotope Atom Count: 0
Defined Atom Stereocenter Count: 0
Undefined Atom Stereocenter Count: 0
Defined Bond Stereocenter Count: 0
Undefined Bond Stereocenter Count: 0
Covalently-Bonded Unit Count: 1

Compound Is Canonicalized: Yes
Physical state: solid
Form: powder
Color: white, brown
Odor: No data available
Melting point/ range: 100 - 102 °C
Boiling point/boiling range: 256 - 258 °C
Flammability: No data available
Upper explosion limit / Upper flammability limit: No data available
Lower explosion limit / Lower flammability limit: Lower flammability limit 1,5 %(V)

Flash point: 136 °C
Method: closed cup
Autoignition temperature: 540 °C
Decomposition temperature: No data available
pH: 8,7
Viscosity, dynamic: No data available
Viscosity, kinematic: No data available
Flow time: No data available
Solubility(ies)
Water solubility: 39,3 g/l
pH: 7

Method: OECD Test Guideline 105
Partition coefficient: noctanol/water: log Pow: 0,12
Method: OECD Test Guideline 107
Bioaccumulation is not expected.
Vapor pressure: 0,108 Pa
Method: OECD Test Guideline 104
Relative density: No data available
Density: 0,72 g/cm3
GLP: yes

Relative vapour density: No data available
Explosives: Not classified as explosive
Oxidizing properties: none
Burning rate: No data available
Evaporation rate: No data available
Molecular weight: 108,14 g/mol
Melting point: 100-102 °C
Boiling point: 256-258 °C
Density: 1,27 g/cm3

bulk density: 530kg/m3
vapor density: 3.7
vapor pressure: 0.01 mm Hg
refractive index: 1.6339
Flash point: 110°C
storage temp.: 2-8°C
solubility: H2O: 1 tablet/10 mL, clear, colorless
form: tablet
Colour Index: 76010
pka: 4.46
color: white to off-white

PH Range: Green Q uorescence (3.1) to nonQ uorescence (4.4)
PH: 7-8
explosive limit: 1.5%(V)
Water Solubility: <0.1 g/100 mL
Sensitive: Air & Light Sensitive
Merck: 14,7284
BRN: 606074
Henry's Law Constant: 1.4×103 mol/(m3Pa)
Exposure limits: TLV-TWA 0.1 mg/m3; carcinogenicity: A2- Suspected Human Carcinogen
Stability: Stable. Incompatible with strong oxidizing agents.
Major Application: bottom antireflective coatings, semiconductor devices, hair dyes, detecting antibody, substrate for horseantibody, glucose, streptomycin, penicillin, sulfonamide, neuroglobin, substrate for horseradish peroxidase

InChI: 1S/C6H8N2/c7-5-3-1-2-4-6(5)8/h1-4H,7-8H2
InChIKey: GEYOCULIXLDCMW-UHFFFAOYSA-N
SMILES: Nc1ccccc1N
LogP: 0.12-0.17
CAS DataBase Reference: 95-54-5
EWG's Food Scores: 5-8
FDA UNII: 8B713N8Q0F
IARC: 2B
NIST Chemistry Reference: 1,2-Benzenediamine
EPA Substance Registry System: 1,2-Phenylenediamine
UNSPSC Code: 12352204
NACRES: NB.21

FIRST AID MEASURES of O-PHENYLENEDIAMINE:
-Description of first-aid measures
*General advice:
Show this material safety data sheet to the doctor in attendance.
*If inhaled:
After inhalation:
Fresh air.
*In case of skin contact:
Take off immediately all contaminated clothing.
Rinse skin with
water/ shower.
*In case of eye contact:
After eye contact:
Rinse out with plenty of water.
Call in ophthalmologist.
Remove contact lenses.
*If swallowed:
After swallowing:
Immediately make victim drink water (two glasses at most).
Consult a physician.
-Indication of any immediate medical attention and special treatment needed.
No data available

ACCIDENTAL RELEASE MEASURES of O-PHENYLENEDIAMINE:
-Environmental precautions:
Do not let product enter drains.
-Methods and materials for containment and cleaning up:
Cover drains.
Collect, bind, and pump off spills.
Observe possible material restrictions.
Take up dry.
Dispose of properly.
Clean up affected area.

FIRE FIGHTING MEASURES of O-PHENYLENEDIAMINE:
-Extinguishing media:
*Suitable extinguishing media:
Carbon dioxide (CO2)
Foam
Dry powder
*Unsuitable extinguishing media:
For this substance/mixture no limitations of extinguishing agents are given.
-Further information:
Prevent fire extinguishing water from contaminating surface water or the ground water system.

EXPOSURE CONTROLS/PERSONAL PROTECTION of O-PHENYLENEDIAMINE:
-Control parameters:
--Ingredients with workplace control parameters:
-Exposure controls:
--Personal protective equipment:
*Eye/face protection:
Use equipment for eye protection.
Safety glasses
*Body Protection:
protective clothing
*Respiratory protection:
Recommended Filter type: Filter A
-Control of environmental exposure:
Do not let product enter drains.

HANDLING and STORAGE of O-PHENYLENEDIAMINE:
-Conditions for safe storage, including any incompatibilities:
*Storage conditions:
Tightly closed.
Dry.

STABILITY and REACTIVITY of O-PHENYLENEDIAMINE:
-Chemical stability:
The product is chemically stable under standard ambient conditions (room temperature).
-Possibility of hazardous reactions:
No data available