Azo Dye Purification Using Urea Complexation
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Solution Overview
Problem
Azo dye compounds with high crystallinity are difficult to dissolve in solvents, making it challenging to obtain high purity through purification methods like recrystallization.
Innovation Solution
An azo dye composition comprising an azo dye compound represented by Formula (I) and a urea compound represented by Formula (II), where at least one of R11, R12, R13, or R14 is a halogen atom, and R21 and R22 are aliphatic groups, is used, with a method involving precipitation using a first solvent and a second solvent different from the urea compound, to reduce impurities and achieve high purity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If an azo dye compound with high crystallinity is used, then the dye has good stability and color fastness, but it becomes difficult to dissolve in solvents and hard to purify by recrystallization
Solution Approach 1:
A urea compound is introduced as an intermediary substance to facilitate the dissolution of the azo dye compound. The urea compound forms a complex with the azo dye, increasing its solubility in the solvent and enabling effective purification through recrystallization while maintaining the dye's stability
Solution Approach 2:
The solubility parameters of the azo dye compound are changed by forming a complex with the urea compound. This chemical interaction modifies the physical properties of the dye, particularly its solubility characteristics, allowing it to dissolve in solvents where it would otherwise be insoluble due to high crystallinity
2Stability of the object's composition
If an azo dye compound with high crystallinity is used, then the dye has good stability, but it becomes difficult to obtain high purity by purification
Solution Approach 1:
The urea compound acts as a mediating agent during the purification process. It forms a soluble complex with the azo dye compound, allowing impurities to be separated through filtration or decantation. The complex can then be decomposed to yield high-purity dye, thus achieving both stability and purity
Solution Approach 2:
The urea compound is added before the purification step to pre-modify the azo dye compound's solubility characteristics. This preliminary action enables subsequent purification operations to be effective, transforming an otherwise unpurifiable high-crystallinity dye into a purifiable form
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The method results in an azo dye compound of high purity, with a reduced amount of impurities, as the interaction between the azo dye compound and urea compound facilitates solubility and purification, allowing for the isolation of a high-purity azo dye compound.
Implementation Method 1
an azo dye composition including an azo dye compound and a urea compound... the azo dye composition includes an azo dye compound and a urea compound
Implementation Method 2
precipitating the azo dye composition by bringing the crude product into contact with a first solvent in a second solvent
Data Source
AI summary
Provided are an azo dye composition including an azo dye compound represented by Formula (I) and a urea compound represented by Formula (II), and a method for producing an azo dye composition. R11, R12, R13 and R14 each independently represent a hydrogen atom, a halogen atom, or an aliphatic group; R15 represents an aliphatic group; R21 and R22 each independently represent a hydrogen atom, an aliphatic group, or an aromatic group; and n represents an integer from 0 to 2.