1-Naphtholbenzein is an organic dye belonging to the benzein family, with the chemical formula C₂₇H₁₈O₂. It is known for its distinctive color response and good stability and is generally insoluble in water but soluble in alcohol and other organic solvents. The compound exhibits pH-sensitive color changes due to structural transformations under acidic and alkaline conditions. It is commonly used in acid-base reactions, titrations and pH measurements, where its visible color change helps identify changes in acidity or alkalinity. Its pronounced color response and compatibility with organic solvents make 1-Naphtholbenzein particularly suitable for analytical titrations performed in nonaqueous or low-water media.
CAS No.: 145-50-6
Synonyms: 4,4′-(α-Hydroxybenzylidene)di-1-naphthol, α-naphtholbenzein, p-naphtholbenzein.
| Physical Properties | |
| Chemical formula | C27H18O2 |
| IUPAC Name | (4Z)-4-[(4-hydroxynaphthalen-1-yl)- phenylmethylidene]naphthalen-1-one |
| Molecular weight | 374.44 g/mol |
| Solubility | Insoluble in water. Soluble in ethanol, acetone, and acetic acid. |
| Density | 1.28 g/cm3 |
| Appearance | Dark red to red-brown to brown-black to orange-brown powder |
| Storage | Store at room temperature |
| Chemical Properties | |
| Color | Dark reddish black |
| Physical State | Solid |
| Melting Point | 185 °C |
| λmax | 622-626 nm |
| Ph | 8.5 – 9.8 |
| Odor | Odorless |
| Pictograms : |  |
| Hazard Statements : | H319: Causes serious eye irritation. H335: May cause respiratory irritation. |
| Precautionary Statements: | P261: Avoid breathing dust/fume/gas/mist/vapours/spray. P302+P352: IF ON SKIN: Wash with plenty of water. P305+P351+P338: IF IN EYES: Rinse cautiously with water for several minutes. Remove contact lenses, if present and easy to do. Continue rinsing |
1-Naphtholbenzein is an organic dye belonging to the benzein family, with the chemical formula C₂₇H₁₈O₂. It is known for its distinctive color response and good stability and is generally insoluble in water but soluble in alcohol and other organic solvents. The compound exhibits pH-sensitive color changes due to structural transformations under acidic and alkaline conditions. It is commonly used in acid-base reactions, titrations and pH measurements, where its visible color change helps identify changes in acidity or alkalinity. Its pronounced color response and compatibility with organic solvents make 1-Naphtholbenzein particularly suitable for analytical titrations performed in nonaqueous or low-water media.
CAS No.: 145-50-6
Synonyms: 4,4′-(α-Hydroxybenzylidene)di-1-naphthol, α-naphtholbenzein, p-naphtholbenzein.
| Physical Properties | |
| Chemical formula | C27H18O2 |
| IUPAC Name | (4Z)-4-[(4-hydroxynaphthalen-1-yl)- phenylmethylidene]naphthalen-1-one |
| Molecular weight | 374.44 g/mol |
| Solubility | Insoluble in water. Soluble in ethanol, acetone, and acetic acid. |
| Density | 1.28 g/cm3 |
| Appearance | Dark red to red-brown to brown-black to orange-brown powder |
| Storage | Store at room temperature |
| Chemical Properties | |
| Color | Dark reddish black |
| Physical State | Solid |
| Melting Point | 185 °C |
| λmax | 622-626 nm |
| Ph | 8.5 – 9.8 |
| Odor | Odorless |
| Pictograms : | |
| Hazard Statements : | H319: Causes serious eye irritation. H335: May cause respiratory irritation. |
| Precautionary Statements: | P261: Avoid breathing dust/fume/gas/mist/vapours/spray. P302+P352: IF ON SKIN: Wash with plenty of water. P305+P351+P338: IF IN EYES: Rinse cautiously with water for several minutes. Remove contact lenses, if present and easy to do. Continue rinsing |
1-Naphtholbenzein is mainly used as a pH indicator in acid–base titrations particularly in nonaqueous systems. It is also used in sequential injection analysis for monitoring acid–base titration endpoints through its characteristic color change.
1-Naphtholbenzein is also known as α-Naphtholbenzein (alpha-naphtholbenzein) or p-Naphtholbenzein. It has the chemical formula C₂₇H₁₈O₂ and belongs to the benzein family of organic dyes.
