База Бандровски

Description

Bandrowski's base is a trimeric oxidation product of para-phenylenediamine (PPD), one of the most common components of oxidative hair dyes. It is formed during the oxidation of PPD with hydrogen peroxide or enzymatically (laccase) in an alkaline environment; the limiting stage is the electrophilic attack of the protonated p-benzoquinonediimine on the neutral PPD molecule. The compound belongs to the class of quinonediimine oligomers and is considered as a marker of allergenicity of oxidative hair dyes.

Basic Attributes

• CAS No: 20048-27-5
• Chemical formula: C18H18N6
• Molecular Weight: 318.38
• Exact weight: 318.38
• UNII: 63ZRE89T3Q
• DSSTox ID: DTXSID9044031
• PSA Specifications: 129
• XLogP3: 1.4

Physico-chemical characteristics

• Density: 1.36±0.1 g/cm3 (predicted)
• Boiling point: 523.5 °C at 760 mm Hg. Art.
• Flash point: 270.4 °C
• Refractive index: 1.714
• Vapor pressure: 4.71×10⁻¹¹ mm Hg. Art. at 25 °C

Formation and chemical properties

The Bandrowski base is formed by the oxidation of para-phenylenediamine with oxidizing agents (hydrogen peroxide) or enzymatically with the participation of laccase. The reaction kinetics at pH above 8 is determined by the electrophilic attack of protonated p-benzoquinonediimine, an intermediate product of PPD oxidation, on the unoxidized PPD molecule, followed by cyclization into a trimeric structure. Reaction conditions (temperature, pH, concentration of reagents) determine the yield of the target product and the proportion of by-products of dimeric and polymeric oxidation products.

Scope of application

The compound is formed as a by-product of the use of para-phenylenediamine-based oxidative hair dyes and is considered in dermatological and toxicological studies to be one of the main allergens responsible for hair dye contact dermatitis. In analytical chemistry, the Bandrowski base is used as a reference compound in the development of methods for quality control of coloring compositions and assessment of the degree of oxidation of PPD in finished products.

Physico-chemical interpretation

An XLogP3 value of 1.4 indicates the molecule is moderately lipophilic. The polar surface area of ​​PSA 129 Å2 reflects the contribution of six quinonediimine and amine nitrogen atoms in the trimer structure. The extremely low vapor pressure (4.71 × 10⁻¹¹ mmHg at 25 °C) indicates that the compound is practically nonvolatile at room temperature, which is typical for high molecular weight aromatic amines.

Safety Information

There is no data on hazard classification, transport codes and GHS phrases for the Bandrowski database in the original dump and open sources. The compound is prepared and used primarily in laboratory quantities for analytical and toxicological studies.

Storage and transportation

Store in a cool, dry place, protected from light and moisture, in a hermetically sealed container - the compound is capable of further oxidation and polymerization when exposed to air. When working, use gloves and safety glasses, taking into account the known allergenic potential of the compound and its precursor - para-phenylenediamine.