PRODUCTS

o-TOLUIDINE

o-toluidine is used as raw materials of pesticide like Tricyclazole, insecticide Chlordimeform, chloromethiuron, and acetochlor.
o-toluidine is used as raw materials of Thiofide.
o-toluidine is used as raw material of saccharin.

CAS Number: 95-53-4
EC / EINECS Number: 202-429-0
MDL Number: MFCD00007730
IUPAC Name: 2-Methylaniline (also known as o-methylaniline)
Molecular Formula: C₇H₉N
Molecular Weight: ≈ 107.15 g/mol

SYNONYMS:
o-Aminotoluene, o-Methylaniline, 2-Methylaniline, 2-Methyl-1-aminobenzene, o-Tolylamine, Benzenamine, 2-methyl-, 2-Toluidine, o-Toluide, o-Toluidin, o-Toluidyna, Aniline, 2-methyl-, 2-Methylaniline, o-Methylaniline, o-Toluidine, 1-Amino-2-methylbenzene, 2-Aminotoluene, 2-Toluamine, o-Toluidine, 2-Methylaniline, 95-53-4, 2-Toluidine, o-Tolylamine, o-Methylaniline, 2-AMINOTOLUENE, 2-Methylbenzenamine, ortho-toluidine, o-Aminotoluene, 2-Methyl-1-aminobenzene, o-Methylbenzenamine, Benzenamine, 2-methyl-, 1-Amino-2-methylbenzene, 2-Amino-1-methylbenzene, o-Toluidin, o-Toluidyna, 1-Methyl-2-aminobenzene, Aniline, 2-methyl-, 2-Methylbenzamine, RCRA waste number U328, 2-methylphenylamine, DTXSID1026164, C.I. 37077, B635MZ0ZLU, NSC-15348, DTXCID206164, CHEBI:66892, NSC15348, RefChem:6080, CI 37077, 202-429-0, ortho Toluidine, 2-methyl-aniline, Benzenamine, methyl-, o-Toluidin [Czech], 2-Toluidine-d7, o-Toluidyna [Polish], o-Toluide, MFCD00007730, NSC 15348, O-TOLUIDINE-D3 (METHYL-D3), 121536-13-8, O-Toluidin (CZECH), O-Toluidyna (POLISH), 68408-22-0, CAS-95-53-4, CCRIS 597, HSDB 2042, Prilocaine EP impurity B, EINECS 202-429-0, RCRA waste no. U328, ortho-tolylamine, AI3-24383, o-tolyl-amine, 2-tolylamine, 2-amino toluene, 2 -methylaniline, 2-methyl aniline, 2-(methyl)aniline, 51V, o-Toluidine, liquid, 2-methyl-benzenamine, o-Toluidine, 98%, Prilocaine Impurity 31, o-Toluidine, >=99%, O-TOLUIDINE [MI], O-TOLUIDINE(1%), EC 202-429-0, CHEMBL1381, WLN: ZR B1, SCHEMBL11863, SCHEMBL15789, SCHEMBL61229, SCHEMBL67429, SCHEMBL74259, SCHEMBL75807, o-Toluidine, liquid or solid, MLS002415766, 2-Aminotoluene (o-toluidine), BIDD:ER0679, SCHEMBL138256, SCHEMBL294766, 2-AMINOTOLUENE [HSDB], ORTHO-TOLUIDINE [IARC], SCHEMBL1077811, SCHEMBL2155182, o-Toluidine, analytical standard, SCHEMBL29441724, O-Toluidine (ACD/Name 4.0), o-Toluidine, p.a., 99.5%, MSK1218, 2-Methylbenzenamine (o-Toluidine), HMS3039B11, BB_SC-07050, STR00213, Tox21_201256, Tox21_300179, EBC-41021, SBB028141, STL163331, 2-Methylphenylamine (ACD/Name 4.0), AKOS000119109, o-Toluidine 500 microg/mL in Methanol, NCGC00091368-01, NCGC00091368-02, NCGC00091368-03, NCGC00091368-04, NCGC00253986-01, NCGC00258808-01, o-Toluidine 10 microg/mL in Cyclohexane, BP-21341, SMR001370921, o-Toluidine 100 microg/mL in Cyclohexane, PRILOCAINE IMPURITY B [EP IMPURITY], NS00008265, o-Toluidine, SAJ special grade, >=99.0%, ST45255278, T0299, EN300-33459, o-Toluidine, purum p.a., >=99.5% (GC), C90102, F043316, Q311695, o-Toluidine, liquid or solid [UN1708] [Poison], Z57127943, F2190-0418, PRILOCAINE HYDROCHLORIDE IMPURITY B [EP IMPURITY], InChI=1/C7H9N/c1-6-4-2-3-5-7(6)8/h2-5H,8H2,1H, 97917-08-3, 2-Aminotoluene, 2-Methylaniline, O-toluidine (ar)-isomer 2-toluidine lithium salt 2-toluidine ccris 597 o-toluidyna rcra waste number U328 2-toluidine, (ar)- (ar)-2-toluidine 2-toluidine, (ar)-isomer, o-aminotoluene, 2-aminotoluene, 1-methyl-2-aminobenzene, o-methylaniline, 2-methylaniline, ortho-toluidine, o-Aminotoluene, 1-amino-2-methylbenzene, o-aminotoluene, 2-aminotoluene, CI 37077, 1-methyl-2-aminobenzene, o-methylaniline, 2-methylaniline, o-methylbenzenamine, 2-methylphenylamine, o-toluidine, 2-toluidine, o-tolylamine, Benzenamine,2-methyl-, o-Toluidine, 2-Methylbenzenamine, 2-Aminotoluene, o-Methylaniline, o-Methylbenzenamine, 2-Methyl-1-aminobenzene, 2-Toluidine, 2-Methylaniline, o-Tolylamine, 1-Amino-2-methylbenzene, o-Aminotoluene, 2-Amino-1-methylbenzene, 2-Methylphenylamine, 2-Tolylamine, NSC 15348, Benzenamine, 2-methyl-, o-Aminotoluene, o-Methylaniline, o-Methylbenzenamine, o-Tolylamine, 1-Amino-2-methylbenzene, 2-Aminotoluene, 2-Methyl-1-aminobenzene, 2-Methylaniline, 2-Methylbenzenamine, 2-Toluidine, 2-Amino-1-methylbenzene, 1-Methyl-2-aminobenzene, o-Toluide, o-Toluidin, o-Toluidyna, Aniline, 2-methyl-, C.I. 37077, Rcra waste number U328, NSC 15348

o-toluidine is an organic compound with the chemical formula C7H9N.
o-toluidine is a colorless to pale-yellow liquid with a poor solubility in water.
o-toluidine is a clear colorless or light yellow liquid.

o-toluidine may become reddish brown on exposure to air and light.
o-toluidine has about the same density as water and is very slightly soluble in water.
o-toluidine is an aminotoluene in which the amino substituent is ortho to the methyl group.

o-Toluidine (ortho-toluidine) is an organic compound with the chemical formula C7H9N.
o-Toluidine is primarily used in the manufacture of dyes.
o-Toluidine has been reported in Camellia sinensis with data available.

o-Toluidine is a synthetic, light sensitive, light yellow liquid that is slightly soluble in water and miscible with carbon tetrachloride, diethyl ether and ethanol.
o-toluidine is a synthetic, light sensitive, white crystalline powder that is soluble in dimethylsulfoxide and ethanol.

o-Toluidine and o-toluidine hydrochloride are used primarily as intermediates in the manufacture of dyes and pigments.
The chemical properties of the toluidines are quite similar to those of aniline and toluidines have properties in common with other aromatic amines.

Due to the amino group bonded to the aromatic ring, the toluidines are weakly basic.
None of the toluidines is very soluble in pure water, but will become soluble if the aqueous solution is acidic due to formation of ammonium salts, as usual for organic amines.

At room temperature and pressure, ortho- and meta-toluidines are viscous liquids, but para-toluidine is a flaky solid.
This can be explained by the fact that the p-toluidine molecules are more symmetrical and fit into a crystalline structure more easily.
p-Toluidine can be obtained from reduction of p-nitrotoluene.

p-Toluidine reacts with formaldehyde to form Troger's base.
O-toluidine is an aminotoluene in which the amino substituent is ortho to the methyl group.
o-toluidine is a clear colorless or light yellow liquid.

o-Toluidine is an organic compound with the chemical formula CH3C6H4NH2.
o-toluidine is the most important of the three isomeric toluidines.
o-Toluidine undergoes chemically oxidative polymerization with aniline in the presence of ammonium persulfate as an oxidant in HCl medium.

o-Toluidine (ortho-toluidine) is an organic compound with the chemical formula C7H9N.
o-toluidine is a colorless to pale-yellow liquid with a poor solubility in water.
o-toluidine is a colorless to pale-yellow liquid.

o-toluidine is an organic compound with the chemical formula C7H9N.
o-Toluidine is primarily used in the manufacture of dyes.
o-toluidine is an organic compound with the chemical formula C7H9N.

This arylamine, o-toluidine, is a colorless to pale-yellow liquid with a poor solubility in water.
o-Toluidine (ortho-toluidine) is an organic compound with the chemical formula CH3C6H4NH2.
o-toluidine is the most important of the three isomeric toluidines.

o-toluidine is a colorless liquid although commercial samples are often yellowish.
o-toluidine is a precursor to the herbicides metolachlor and acetochlor.
o-toluidine appears as a clear colorless or light yellow liquid.

o-toluidine may become reddish brown on exposure to air and light.
Flash point of o-toluidine is 185 °F.
o-toluidine has about the same density as water and is very slightly soluble in water.

Vapors of o-toluidine are heavier than air.
o-toluidine is an aminotoluene in which the amino substituent is ortho to the methyl group.
o-toluidine is soluble in water(15g/L).

o-Toluidine, also known as 2-methylaniline, is an organic compound with the molecular formula C₇H₉N and the structural formula CH₃C₆H₄NH₂, featuring a benzene ring with an amino group and an adjacent (ortho) methyl substituent.
o-toluidine is industrially produced primarily through the catalytic hydrogenation of o-nitrotoluene.

As a pale yellow to colorless liquid with an aromatic odor, o-toluidine has a boiling point of 200.3 °C, a melting point of -23.7 °C, and a density of 1.01 g/cm³ at 20 °C; it exhibits low water solubility (1.5 g/L at 25 °C) but is miscible with most organic solvents, and it may darken to reddish-brown upon prolonged exposure to air and light.

USES and APPLICATIONS of o-TOLUIDINE:
o-toluidine is used by clinical laboratories.
o-Toluidine is used or applied in different circumstances.
o-toluidine is used the most for dye, especially for coloring hair.

The other usages of o-toluidine are specific determination of glucose in blood and the most recent one, the separation of toxic metal ions, which is still in the research phase.
o-toluidine is used as an intermediate of the manufacturing of triphenylmethane dyes and safranine colors.

o-toluidine is an antioxidant in rubber manufacturing and a pharmaceutical intermediate.
o-toluidine has been used as a laboratory reagent in glucose analysis and also used in the preparation of ion exchange resins and making various colors fast to acid.

o-Toluidine is used in the manufacture of various dyes, in printing textiles blue-black and as an intermediate in rubber chemicals, pesticides, and pharmaceuticals.
o-Toluidine and its hydrochloride salt are used primarily as intermediates in the manufacture of dyes and pigments for printing textiles, in color photography, and as biologic stains.

In addition, o-toluidine is used as an intermediate for rubber vulcanizing chemicals, pharmaceuticals, and pesticides.
Other minor uses include intermediate for organic synthesis and clinical laboratory reagent for glucose analysis.
o-toluidine was used in determination of glucose in biological materials.

o-toluidine was used as precursor in the synthesis of poly(o-toluidine) and copper nanoparticle composite material.
o-toluidine is an important intermediate for the production of dyes and pigments and can be used to prepare direct red 62, red base RL, red base G, juvenile base GBC, alkaloid, peptone AS-D, acid red 35, 158, 265, solvent red 124, diazo group of azo dyes and coupling component, pigment yellow 14, yellow 17, Blue 19.

o-toluidine is used as corrosion inhibitor and other raw materials.
In organic synthesis, o-toluidine are also used in synthesis of heterocyclic compounds indole and its derivatives.
o-Toluidine is primarily used in the manufacture of dyes.

o-toluidine is used in the production of dye products such as date red base GBC, scarlet base G, red base RL, naphthol ASD, acid pink 3B, basic magenta and basic pink T, as well as pesticides insecticidal amidine, saccharin, vulcanization accelerator, Beneficiation agent toluene arsenic acid, etc.

o-toluidine is used in determination of glucose in biological materials.
o-Toluidine is used mainly as an intermediate in chemical synthesis, especially in: Dye and pigment production, including azo and indigo dyes, Rubber chemicals and vulcanization additives, Pharmaceutical intermediates in the synthesis of drugs and fine chemicals, and Pesticide synthesis.

o-toluidine has also been used historically in analytical chemistry (e.g., glucose determination) and as a precursor to herbicides.
o-Toluidine is used in the production of dyes, as a presumptive test for blood in forensic science.
And o-toluidine is also used in determination of glucose in biological materials, as a precursor in the synthesis of poly(o-toluidine) and copper nanoparticle composite material.

o-Toluidine serves as a key intermediate in the chemical industry, particularly for manufacturing azo dyes used in textiles, as well as rubber vulcanization accelerators, certain pharmaceuticals, and pesticides.
o-toluidine's reactivity as an aromatic amine enables derivatization into various compounds, including diazonium salts for dye synthesis.

-Dye uses of o-toluidine:
o-Toluidine has been used as a dye precursor since the 19th century, when synthetic dye was produced.
In the years that followed, the aromatic amine, o-toluidine, functioned as a precursor of many dyes and pigments for consumer goods.

But when the carcinogenicity of o-toluidine for animals was recognized, and that it potentiality could be carcinogenic for humans, the production of o-toluidine and its use in dye manufacturing has been largely banned in the Western world and in many parts of the East.

But there are still a few dyes that are based on this compound.
The most known compounds are petroleum products and yellow organic pigments.
o-toluidine is also an essential compound in the production of 4-chloro-o-toluidine and 4-amino-2′,3-dimethylazobenzene, which are also dyes.

-Specific determination of glucose:
o-Toluidine can also be used for measuring serum glucose concentration, in the form of acetic acid–o-toluidine.
The o-toluidine reaction for the estimation of glucose concentration in the serum gained massive popularity in the 1970s.
This method was mostly used by clinical laboratories.
Because of the potential health hazard, the laboratories now have a modified method by using alternative compounds.

-Separation of toxic metal ions:
The increasing level of heavy metals in the environment is a serious environmental problem.
Various methods have been developed to remove these metals from aqueous systems, but these methods have limitations.
Because of the limitations, researchers prompted to exploit inorganic materials as ion exchangers.

These inorganic ion exchangers are able to obtain specific metal ions/anions or organic molecules.
Following research in 2010, there has been a synthesis and analytical application on a new thermally stable composite cation exchange material: poly-o-toluidine stannic molybdate.
This material showed a high selectivity for Pb2+ and Hg2+ metal ions.

-Dyes and rubber chemicals use of o-toluidine:
o-Toluidine serves as a key intermediate in the production of various dyes, particularly azo dyes, where it is converted into diazonium salts that couple with phenols or naphthols to form pigments applied in textiles and printing inks.

This diazotization process leverages o-toluidine's reactivity as an aromatic amine to yield colorants such as Acid Red 24 and Solvent Red 24, which are used in industrial dyeing applications.
Additionally, o-toluidine contributes to the synthesis of thioindigo dyes, serving as a precursor for indigo derivatives employed in vat dyeing of cotton fabrics.

Other examples include its role in producing magenta dyes like Magenta I (Basic Violet 14) and safranine T (Basic Red 2), which find use in direct dyeing processes for textiles.
In the rubber industry, o-toluidine is utilized as an intermediate for manufacturing vulcanization accelerators and antioxidants that enhance the durability and performance of rubber products, such as tires.

A prominent example is di-o-tolylguanidine (DOTG), synthesized from o-toluidine, which acts as a delayed-action accelerator in conjunction with thiazoles and thiurams to promote efficient crosslinking during vulcanization of natural and synthetic rubbers.
This compound improves scorch safety and curing rates, contributing to the production of high-quality rubber goods.

The dye and rubber chemicals sectors represent the principal applications for o-toluidine, accounting for the largest share of its global consumption due to its versatility in industrial colorants and polymer additives.
Over 90 dyes incorporate o-toluidine as a building block, underscoring its significant market impact in these areas.

-Agrochemicals and pharmaceuticals use of o-toluidine:
o-Toluidine functions as a critical intermediate in the production of several agrochemicals, particularly herbicides.
o-toluidine is essential for synthesizing the chloroacetanilide herbicides metolachlor and acetochlor, which are applied pre-emergence to control annual grasses and broadleaf weeds in crops such as corn and soybeans.

The synthesis begins with N-alkylation of o-toluidine using ethylating agents to yield 6-ethyl-o-toluidine, followed by acylation with chloroacetyl chloride to form the active herbicide structure; this pathway accounts for a significant portion of o-toluidine's industrial consumption in agriculture.

In pesticide manufacturing, o-toluidine contributes to the creation of select fungicides and insecticides via derivative formation, such as imine or amide linkages.
For instance, it is incorporated into triflumizole, a broad-spectrum imidazole fungicide effective against powdery mildew and other fungal pathogens on fruits and vegetables, through condensation reactions forming the N-(o-toluidine) ethylidene core.

Similarly, pioxaniliprole, an anthranilic diamide insecticide targeting lepidopteran pests in rice and vegetables, is derived from o-toluidine by initial acylation with chloroacetyl chloride, followed by cyclization to a pyrazolone intermediate and further elaboration.
These applications leverage o-toluidine's reactivity as an aromatic amine to build heterocyclic structures with biological activity.
In the pharmaceutical sector, o-toluidine serves as a precursor for prilocaine, a local anesthetic used in dental and minor surgical procedures.

The synthesis involves acylation of o-toluidine with 2-chloropropionyl chloride to produce the intermediate amide, which is then displaced with isopropylamine to yield prilocaine; notably, prilocaine undergoes in vivo metabolism back to o-toluidine, which can lead to methemoglobinemia at high doses due to hemoglobin oxidation.

METHODS OF MANUFACTURING of o-TOLUIDINE:
The preparation method is prepared by catalytic hydrogenation reduction of o-nitrotoluene.
Due to the different hydrogenation catalysts, the reaction conditions are different.
For example, a copper catalyst is used and the reaction temperature is 260°C, and a nickel catalyst can also be used.

CHEMICAL PROPERTIES of o-TOLUIDINE:
o-Toluidine is an aromatic amine derived from toluene with an amino group at the ortho position relative to the methyl group.
In solution, o-toluidine behaves similar to aniline, showing basic properties and undergoing typical aromatic amine reactions such as diazotization.
o-toluidine can oxidize gradually on exposure to air and light, turning from colorless to yellow or reddish brown.

NOTES of o-TOLUIDINE:
Air & Light Sensitive.
Keep o-toluidine container tightly closed.
Store o-toluidine in cool, dry conditions in well sealed containers.
o-Toluidine, aka ortho metyl aniiline, a potentially useful synthetic reagent.

OCCURRENCE/USE of o-TOLUIDINE:
Production of dyes, vulcanization accelerator, organic synthesis; photographic dye; reagent in clinical assay for glucose and hemoglobin; component of tobacco smoke

TOLUIDINE ISOMERS:
Toluidine has three isomers: o-toluidine, m-toluidine and p-toluidine, while o-toluidine is the situ substitution product and m-toluidine is the shift substitution product.

SYNTHESIS AND REACTIONS of o-TOLUIDINE:
o-Toluidine is produced industrially by nitration of toluene to give a mixture of nitrotoluenes, favoring the ortho isomer.
This mixture is separated by distillation.
2-Nitrotoluene is hydrogenated to give o-toluidine.
The conversion of o-toluidine to the diazonium salt gives access to the 2-bromo, 2-cyano-, and 2-chlorotoluene derivatives.
N-acetylation is also demonstrated.

CHEMICAL AND PHYSICAL PROPERTIES of o-TOLUIDINE:
o-toluidine is a clear colorless or light yellow liquid.
o-toluidine may become reddish brown on exposure to air and light.
o-toluidine may form white precipitate in the presence of formaldehyde.

o-toluidine is slightly soluble in water.
o-toluidine is soluble in dilute acid, alcohol and ether.
Relative density: 1.004 (20℃).

Melting point: -16.3℃ (β), -24.4℃ (α).
Boiling point: 199.7℃.
Flash point: 185°F.

Spontaneous ignition point: 482.2℃.
Vapor density: 3.69.
o-toluidine's vapor can form explosive mixture with air.

The maximum allowable concentration in air is 5 ppm.
o-toluidine has about the same density as water and is very slightly soluble in water.
Vapors of o-toluidine are heavier than air.

The chemical properties of the toluidines are quite similar to those of aniline.
Toluidines have properties in common with other aromatic amines.
Due to the amino group bonded to the aromatic ring, the toluidines are weakly basic.

PROPERTIES, BENEFITS & CHARACTERISTICS of o-TOLUIDINE:
o-Toluidine’s aromatic amine structure provides useful reactivity for electrophilic substitution, diazotization, and coupling reactions.
o-toluidine is a reactive intermediate in industrial chemistry rather than a consumer product.
o-toluidine is slight water solubility and strong solvency in organic solvents support its use in synthetic routes.
Its chemical similarity to aniline means o-toluidine participates in many of the same pathways and reactions.

SYNTHESIS METHOD of o-TOLUIDINE:
o-Toluidine can be synthesized from toluene.
The direct aromatic amination is very effective when done with a parent nitrenium ion.
o-Toluidine can also be synthesized in other ways.

For example, by the amination of toluene with methylhydroxylamine or hydroxylammonium salts in presence of aluminum trichloride.
The reaction using a nitrenium ion is not regionselective and multiple structural isomers will be present in the product.
To obtain pure o-toluidine, the isomers need to be separated.

In the dilute acid medium, o-nitrotoluene is heated together with iron powder and water to synthesize o-toluidine.
O-nitrotoluene is preheated with hydrogen in the induction heater and hydrogenated in the presence of copper catalyst to prepare o-toluidine.

Toluene is aminated by ammonia sodium with the rhodium-carbon catalyst to produce o-toluidine.
Aniline is alkylated with methanol under the catalysis of ferric nitrate and germanium dioxide to produce the finished product o-toluidine.

CHEMICAL PROPERTIES of o-TOLUIDINE:
o-toluidine is a light-yellow liquid, becomes reddishbrown on exposure to air and light.
o-toluidine is soluble in alcohol and ether; very slightly soluble in water.

o-toluidine is a light yellow to reddish brown liquid.
On exposure to light and atmospheric air, o-toluidine quickly turns a dark color.
o-toluidine has extensive use in a large number of industries around the world.

For instance, o-toluidine is used as an intermediate in the manufacture of azo and indigo dyes, pigments, sulfur dyes, pesticides, pharmaceutical products, rubber and vulcanizing chemicals, and similar products.
o-Toluidine is a colorless to pale yellow liquid with a weak, pleasant, aromatic odor.

PHYSICAL PROPERTIES of o-TOLUIDINE:
o-toluidine is a colorless to pale yellow liquid with an aromatic, aniline-like odor.
o-toluidine becomes reddish-brown on exposure to air and light.
Odor threshold concentration is 250 ppb (quoted, Amoore and Hautala, 1983).

OCCURRENCE of o-TOLUIDINE:
o-toluidine has been reported to be a component of tar produced by low-temperature carbonization of coal and has been detected in gasoline fractions from arlan petroleum, tobacco leaf extracts, and in the aroma components of black tea.

CHEMICAL REACTIVITY of o-TOLUIDINE:
Reactivity with Water: No reaction.
Reactivity with Common Materials: No reactions.
Stability During Transport: Stable.
Neutralizing Agents for Acids and Caustics: Not pertinent.
Polymerization: Not pertinent.
Inhibitor of Polymerization: Not pertinent.

PRODUCTION METHODS of o-TOLUIDINE:
The production of o-toluidine is based on the catalytic hydrogenation of O-nitrotoluene or the amination of toluene with methylhydroxylamine in the presence of aluminum trichloride (Windholz 1983).
o-toluidine is available as a technical grade with a minimum of 99.5% purity containing m-toluidine (0.4% maximum) and/or p-toluidine (0.1% maximum) as impurities (Anon. 1978).
The stabilized technical grade may also contain less than 0.5% of unidentified stabilizing agents to prevent darkening.

AIR & WATER REACTIONS of o-TOLUIDINE:
o-toluidine becomes reddish brown upon exposure to air and light.
o-toluidine is slightly soluble in water.

REACTIVITY PROFILE of o-TOLUIDINE:
o-Toluidine neutralizes acids in exothermic reactions to form salts plus water.
o-toluidine may be incompatible with isocyanates, halogenated organics, peroxides, phenols (acidic), epoxides, anhydrides, and acid halides.
Undergoes a hypergolic reaction with red fuming nitric acid.

PROPERTIES of o-TOLUIDINE:
PHYSICAL PROPERTIES
o-Toluidine has the molecular formula C₇H₉N and a molar mass of 107.15 g/mol.
o-toluidine appears as a clear, colorless to light yellow liquid at room temperature, though commercial samples may exhibit a yellowish tint due to impurities and can turn reddish-brown upon prolonged exposure to air and light.

CHEMICAL PROPERTIES
o-Toluidine, with the systematic name 2-methylaniline, features a benzene ring substituted with an amino group (-NH₂) at position 1 and a methyl group (-CH₃) at the ortho position 2.
This structural arrangement distinguishes o-toluidine from aniline (C₆H₅NH₂) and the other toluidine isomers, meta-toluidine (3-methylaniline) and para-toluidine (4-methylaniline), where the methyl group is positioned adjacently, meta, or para relative to the amino substituent, respectively.

As a primary aromatic amine, o-toluidine displays characteristic reactivity centered on the nucleophilic -NH₂ group, which participates in reactions with electrophiles, such as protonation by acids to form salts exothermically or incompatibility with strong oxidizers and bases.

The amino substituent strongly activates the aromatic ring toward electrophilic aromatic substitution, acting as an ortho-para director due to its electron-donating resonance effect, while the ortho methyl group provides additional activation through hyperconjugation but may impose steric hindrance on substitutions at positions adjacent to both substituents.

Spectroscopic analysis confirms the functional groups: the infrared (IR) spectrum shows characteristic N-H stretching absorptions for the primary amine around 3300–3500 cm⁻¹.

In the ¹H nuclear magnetic resonance (NMR) spectrum, the methyl group appears at approximately 2.09 ppm, the amino protons at 3.48 ppm, and the aromatic protons resonate between 6.59 and 7.01 ppm, reflecting the deshielding effects of the substituents.
o-Toluidine is sensitive to oxidation upon exposure to air and light, gradually developing reddish-brown colored impurities over time due to oxidative degradation.

SYNTHESIS of o-TOLUIDINE:
INDUSTRIAL PRODUCTION
o-Toluidine is primarily produced industrially through the nitration of toluene followed by selective hydrogenation of the resulting 2-nitrotoluene.
In the nitration step, toluene is reacted with a mixed acid system consisting of nitric acid (HNO₃) and sulfuric acid (H₂SO₄) under controlled conditions to yield a mixture of mononitrotoluene isomers, where the ortho isomer (2-nitrotoluene) constitutes approximately 60% of the product.

The isomers are then separated via fractional distillation to isolate 2-nitrotoluene, which is subsequently reduced to o-toluidine.
The reduction of 2-nitrotoluene typically occurs through catalytic hydrogenation, either in the vapor phase or liquid phase at elevated temperatures (around 200–300°C) and pressures, using catalysts such as nickel-on-kieselguhr, palladium, or platinum to achieve high selectivity for the primary amine.

This process is conducted continuously in modern facilities to optimize efficiency and minimize byproducts like toluidine isomers or over-reduced compounds.
An alternative route involves the reaction of o-chlorotoluene with sodium amide (NaNH₂) in liquid ammonia, yielding a mixture of o- and m-toluidine, though the nitration-hydrogenation method remains dominant due to its scalability.

Commercial production of o-toluidine was first established in the United Kingdom in 1880, coinciding with the expansion of the aniline dye industry in the late 19th century, and has since become a high-volume chemical manufactured primarily in hubs such as China (16 producers), India (11 producers), and the United States (6 producers as of 1999).

Global annual production reached an estimated 59,000 metric tons in 2001, reflecting its role as a key intermediate in dyes, pigments, and rubber chemicals, with ongoing output in the tens of thousands of tons primarily driven by demand in these sectors.

LABORATORY METHODS
o-Toluidine is commonly synthesized in laboratory settings through the reduction of 2-nitrotoluene, a method that offers versatility for small-scale preparations.
This reduction can be achieved using metal-acid systems such as tin in hydrochloric acid or iron in hydrochloric acid, known as the Béchamp reduction.

In the tin/HCl procedure, 2-nitrotoluene is added to granular tin in concentrated HCl, heated to approximately 100°C for 2 hours, followed by basification with NaOH to liberate the free amine, which is then extracted with an organic solvent like diethyl ether.
Similarly, the iron/HCl variant employs iron powder in aqueous HCl at around 100°C under batch conditions, producing o-toluidine hydrochloride directly, which is isolated by filtration and subsequent neutralization.

These classical approaches are favored in research due to their simplicity and use of inexpensive reagents, though they generate significant inorganic waste.
A milder alternative is catalytic hydrogenation using Raney nickel as the catalyst in ethanol solvent under hydrogen pressure.

The reaction proceeds at elevated temperature and pressure, typically converting 2-nitrotoluene to o-toluidine with high selectivity, as demonstrated in analogous reductions of nitrotoluenes where complete conversion is achieved.
This method avoids harsh acids and is suitable for sensitive substrates, with the catalyst recovered by filtration post-reaction.

Alternative synthetic routes include the Hofmann rearrangement of o-toluamide, where the amide is treated with bromine and sodium hydroxide to form an N-bromoamide intermediate that rearranges upon heating to yield o-toluidine via loss of the carbonyl carbon.

Another option is the partial reduction of 2-nitrotoluene using aqueous ammonium sulfide under phase-transfer conditions in toluene solvent, which selectively reduces the nitro group to amine while minimizing over-reduction.
These routes provide access when 2-nitrotoluene is unavailable or for isotopic labeling studies.

Purification of crude o-toluidine, often contaminated with isomers from nitration precursors, typically involves vacuum distillation to separate the liquid amine (boiling point ~200°C at atmospheric pressure, lower under vacuum) or formation and recrystallization of the hydrochloride salt from aqueous HCl for enhanced purity.
The salt is recrystallized from water or ethanol, then basified to recover the free base.

Laboratory syntheses of o-toluidine via these reductions generally afford yields of 70–90%, depending on the method and scale, with reactions conducted at room temperature to 100°C.
To prevent aerial oxidation of the amine product, an inert atmosphere such as nitrogen is employed, particularly during workup and storage.

PHYSICAL and CHEMICAL PROPERTIES of o-TOLUIDINE:
Common Name: o-Toluidine
IUPAC Name: 2-Methylaniline (also known as o-methylaniline)
Molecular Formula: C₇H₉N
Molecular Weight: 107.15 g/mol
CAS Number: 95-53-4
EC / EINECS Number: 202-429-0
PubChem CID: 7242
ChemSpider ID: 13854136

Physical Form: Liquid with a characteristic aromatic amine odor
Appearance: Colorless to pale yellow liquid; samples may darken on exposure to air and light
Odor: Typical aromatic amine odor
Melting Point: -24.4 °C (α form), -16.3 °C (β form)
Boiling Point: 199.7–200.3 °C
Density (20 °C): 1.008 g/cm³
Vapor Pressure (25 °C): 0.0346 kPa
Vapor Density (air = 1): 3.7–3.69
Flash Point: 85 °C

Autoignition Temperature: 480–482 °C
Solubility in Water: 15–16.6 g/L at 20–25 °C
Solubility (Other Solvents): Soluble in dilute acids, alcohol, and ether
Uses: Chemical intermediate (dyes, pharma, pesticides)
Refractive Index: 1.56987
Viscosity: 4.4335 (20 °C)
XLogP3: 1.3
Hydrogen Bond Donor Count: 1

Hydrogen Bond Acceptor Count: 1
Rotatable Bond Count: 0
Exact Mass: 107.073499291 Da
Monoisotopic Mass: 107.073499291 Da
Topological Polar Surface Area: 26 Å²
Heavy Atom Count: 8
Formal Charge: 0
Complexity: 70.8

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

Common Name: o-Toluidine
IUPAC Name: 2-Methylaniline
Linear Formula: CH3C6H4NH2
Molecular Formula: C7H9N
Molecular Weight: 107.15 g/mol
Exact Mass: 107.15
BRN: 741981
CAS Number: 95-53-4
EC / EINECS Number: 202-429-0

HS Code: 29214300
PSA: 26
XLogP3: 1.43
Appearance: Light yellow to light amber liquid
Physical State (20 °C): Liquid
Form: Liquid
Color: Light yellow to light amber
Odor: Aromatic, aniline-like
Melting Point: -16.3 °C

Boiling Point: 200.3 °C
Density: 1.008 g/cm³ @ 20 °C
Vapor Density (air = 1): 3.7
Vapor Pressure: 0.26 mm Hg (25 °C)
Refractive Index: 1.572
Flash Point: 185 °F
Storage Temperature: 2-8 °C
Solubility in Water: 1.5 g/100 mL (25 °C)

pKa: 4.44 (25 °C)
pH (aqueous solution): 7.4 (20 °C)
Explosive Limit: 1.5–7.5% (V)
Autoignition Temperature: 482 °C
Sensitive: Air & Light Sensitive
Henry's Law Constant: 1.98 at 25 °C (thermodynamic method-GC/UV spectrophotometry)
Dielectric Constant: 6.34
Major Application: Cleaning products, cosmetics, environmental, food and beverages, personal care

InChI: InChI=1S/C7H9N/c1-6-4-2-3-5-7(6)8/h2-5H,8H2,1H3
InChIKey: RNVCVTLRINQCPJ-UHFFFAOYSA-N
SMILES: Cc1ccccc1N
LogP: 1.4 at 24.5 °C
CAS DataBase Reference: 95-53-4
EWG's Food Scores: 6-9
FDA UNII: B635MZ0ZLU
Proposition 65 List: o-Toluidine

IARC: 1 (Vol. Sup 7, 77, 99, 100F) 2012
NIST Chemistry Reference: Benzenamine, 2-methyl-(95-53-4)
EPA Substance Registry System: o-Toluidine (95-53-4)
UNSPSC Code: 41116107
NACRES: NA.24
Common Name: o-Toluidine
IUPAC Name: 2-Methylaniline
Linear Formula: CH3C6H4NH2
Molecular Formula: C7H9N

Molecular Weight: 107.15 g/mol
CAS Number: 95-53-4
EC / EINECS Number: 202-429-0
UNSPSC Code: 12352100
NACRES: NA.22
PubChem Substance ID: 24851137
Beilstein/REAXYS Number: 741981
MDL Number: MFCD00007730
Assay: ≥98.5%

Form: Liquid
Physical State (20 °C): Liquid
Color: Light yellow to amber
Odor: Aromatic, aniline-like
Melting Point: -28 °C
Boiling Point: 200.2 °C
Flash Point: 85 °C (closed cup)
Autoignition Temperature: 482 °C

Decomposition Temperature: No data available
pH (aqueous solution): 7.4 (20 °C)
Viscosity, Dynamic: No data available
Viscosity, Kinematic: No data available
Flow Time: No data available
Solubility in Water: 16.6 g/L (20 °C)
Partition Coefficient (log Pow): 1.4 (24.5 °C)
Method: OECD Test Guideline 107
GLP: Yes

Bioaccumulation: Not expected
Vapor Pressure: 0.35 hPa (25 °C)
Density: 1.008 g/cm³
Relative Vapor Density (air = 1): 3.7
Explosives: Not classified as explosive
Oxidizing Properties: None
Burning Rate: No data available
Self-Ignition: 480 °C

Evaporation Rate: No data available
Storage Temperature: Room temperature (cool and dark place, <15 °C)
Store Under Inert Gas: Yes
Condition to Avoid: Light Sensitive, Air Sensitive
Reaxys Registry Number: 741981
SDBS (AIST Spectral DB): 1454
Merck Index: 9536
Colour Index: 37077
InChI: InChI=1S/C7H9N/c1-6-4-2-3-5-7(6)8/h2-5H,8H2,1H3

InChIKey: RNVCVTLRINQCPJ-UHFFFAOYSA-N
SMILES: CC1=CC=CC=C1N
Refractive Index: 1.5710-1.5740 @ 20 °C
Freezing Point: 2.7 °F
Vapor Pressure: 0.3 mmHg
Vapor Density: 3.69
Specific Gravity: 0.998

Ionization Potential: 7.44 eV
Lower Explosive Limit (LEL): 1.5%
Upper Explosive Limit (UEL): 7.5%
NFPA Health Rating: 3
NFPA Fire Rating: 2
NFPA Reactivity Rating: 0
Water Solubility: 1.5 g/100 mL (25 °C)
Appearance (Color): Clear colorless or yellow to orange or pink to pale brown

FIRST AID MEASURES of o-TOLUIDINE:
-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-TOLUIDINE:
-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-TOLUIDINE:
-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-TOLUIDINE:
-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-TOLUIDINE:
-Conditions for safe storage, including any incompatibilities:
*Storage conditions:
Tightly closed.
Dry.

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