Introduction:
CAS number 132467-74-4 refers to an organic compound belonging to the class of fluoran dyes, commonly known as a leuco dye or color former. This compound is also known commercially under names such as Green GN-2.
It is typically a yellowish to greenish-yellow crystalline powder. And is recognized by multiple systematic names including 3,3-Bis(4-diethylamino-2-ethoxyphenyl)-4-azaphthalide and 7,7-Bis[4-(diethylamino)-2-ethoxyphenyl]furo[3,4-b]pyridin-5(7H)-one.
This product is a synthetic chemical characterized by its ability to undergo reversible color change in response to external stimuli such as heat or pressure, making it a key component in thermal recording technologies.
Synthesis:
The synthesis of 3,3-bis(4-diethylamino-2-ethoxyphenyl)-4-azaphthalide is a multi-step organic process. A typical synthetic route involves:
Formation of the Core: The cyclization of suitable precursors under acidic or basic conditions to form the furo[3,4-b]pyridin-5(7H)-one core structure.
Introduction of Diethylamino Groups: These are introduced via nucleophilic substitution reactions, typically using diethylamine as the nucleophile.
Attachment of Ethoxyphenyl Groups: The ethoxyphenyl groups are attached via electrophilic aromatic substitution reactions using ethoxybenzene derivatives.
Industrial production utilizes similar routes but is optimized for large-scale synthesis, often employing advanced purification techniques to achieve high purity (typically ≥98–99%).
Applications and Uses:
The primary application of this compound is as a color former in thermal and pressure-sensitive recording materials. It is a "leuco dye," a term used for a dye that can switch between a colorless (or lightly colored) state and a colored state. This property is harnessed in a variety of industrial applications.
--Thermal Recording Papers
The most significant commercial use of this compound is as a component in the heat-sensitive coating of thermal paper. When heat is applied (e.g., by a thermal printhead in a receipt or label printer), the dye reacts with a color developer, typically a phenolic compound like bisphenol AF (BPAF), to produce a visible image.
--Thermochromic Materials and Inks
This dye is a critical component in the creation of thermochromic paints and inks. These materials change color in response to temperature fluctuations, making them useful for temperature indicators, novelty items, security printing, and smart packaging.
--Advanced Thermochromic Phase Change Materials
Recent research has demonstrated the use of this compound in the development of reversible thermochromic nanofibrous membranes for advanced applications in smart thermoregulatory textiles.
In a 2023 study, researchers used Green GN-2 as the thermochromic agent, combined with bisphenol AF as the developer and n-butyl stearate as a co-solvent, to create a core-shell structured nanofiber.
This material exhibited significant energy storage and showed clear color change when the encapsulated co-solvent underwent a phase change (melting or crystallization). These are being developed in textiles that can adapt to environmental temperatures and for passive thermal regulation technologies.
--Chemical Research
In chemistry, this compound is used as a building block for the synthesis of more complex organic molecules. Its unique structure allows for the exploration of new reaction mechanisms and the development of novel synthetic methodologies.
Furthermore, its distinct photophysical properties have led to investigations into its potential as a fluorescent probe for biological imaging studies and for the development of potential therapeutic agents.
3,3-Bis(4-diethylamino-2-ethoxyphenyl)-4-azaphthalide; Green GN-2 is most prominently a high-performance leuco dye essential to the thermal printing industry, which underpins the functionality of everyday items like receipt paper and labels.
And its unique properties are being leveraged in advanced applications from thermochromic inks to innovative phase-change materials for smart textiles. As a versatile building block, it continues to be of interest in chemical and materials research for the development of next-generation responsive materials.
Product manager: Joy Wu CONTACT/Email address: Joy@coreychem.com
