DMPD

Description

DMPD (N,N'-Ditolyl-p-phenylenediamine, antioxidant DTPD) is a secondary aromatic amine of the p-phenylenediamine class, CAS 27417-40-9, formula C20H20N2. Belongs to the section of antioxidants.

Basic Attributes

• CAS No.: 27417-40-9
• Chemical formula: C20H20N2
• Molecular weight: 288.394
• Exact weight: 288.163
• EU number: 239-102-7
• PSA specifications: 24.1
• XLogP3: 5.9366

Physico-chemical characteristics

• Density: 1.135 g/cm3
• Melting point: 183.5–185.5 °C
• Boiling point: 475.4 °C at 760 mm Hg. Art.
• Flash point: 301.9 °C
• Refractive index: 1.667
• Vapor pressure: 3.32 × 10⁻⁹ mm Hg. Art. at 25 °C

Scope of application

A primary antioxidant that works by the oxidation chain termination mechanism: it donates a hydrogen atom to peroxy radicals (ROO•) formed during the oxidative degradation of polymers, thereby stopping the oxidation chain reaction. It is widely used as an antioxidant in the production of rubber and plastics, protecting natural rubber and synthetic elastomers from the destructive effects of oxygen and ozone - preventing cracking, loss of elasticity and aging of rubber products, including tires. It has good heat resistance, which allows its use in conditions of elevated temperatures of polymer processing and operation.

According to the chemical mechanism, aromatic amine antioxidants of this class are superior to phenolic analogues in effectiveness against ozone cracking of rubber, since the intermediate aminyl radical formed after the release of hydrogen is stabilized by delocalization in the aromatic system and is able to bind additional molecules of ozone and active oxygen, providing longer-term protection under cyclic mechanical loads characteristic of tires and other dynamically loaded rubber products.

Synonyms

N,N'-Ditolyl-p-phenylenediamine, N,N'-Di(monomethylphenyl)-p-phenylenediamine, DTPD.

Place among the antioxidants of the p-phenylenediamine class

DMPD belongs to a large family of N,N'-disubstituted p-phenylenediamines, which also includes the antioxidants 6PPD (N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine) and IPPD (N-isopropyl-N'-phenyl-p-phenylenediamine), which are widely used in the tire industry. In contrast, DMPD carries two tolyl (methylphenyl) groups instead of alkyl and phenyl substituents, which determines the higher thermal stability of the compound (boiling point 475.4 °C versus significantly lower values ​​for alkylaryl analogues) while maintaining the general mechanism of antioxidant action - oxidation chain termination at the hydrogen atom of the amino group. The symmetrical structure of the molecule (two identical tolyl groups instead of different alkyl and aryl substituents) also simplifies the industrial synthesis of the substance compared to unsymmetrical analogs of the series.

What is not transferred from the sources

Special transport codes and GHS phrases for this product are not given in the dump and are not found in available sources.