Phenylaminohydroxyanthraquinone Dye Synthesis via Cyclic Urea Solvents
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Solution Overview
Problem
Existing processes for producing phenylaminohydroxyanthraquinones fail to meet current application requirements for coloristic properties, necessitating an improved manufacturing method that achieves high yields, purity, and enhanced color performance.
Innovation Solution
A process involving the reaction of 1,4-dichloro-5,8-dihydroxyanthraquinone with phenylamines in the presence of 5- or 6-membered cyclic urea derivatives, such as N,N'-dimethylpropylene urea, and a base like dipotassium hydrogen phosphate, at elevated temperatures, to produce 1,4-diphenylamino-5,8-dihydroxyanthraquinones with improved properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional solvents (N-methylpyrrolidone, 1,2-dichlorobenzene) are used for the reaction, then the manufacturing process is simple and yields are good, but the coloristic properties of the product deteriorate
Solution Approach 1:
The patent changes the solvent parameter from conventional options (N-methylpyrrolidone, 1,2-dichlorobenzene) to cyclic carbonate esters (ethylene carbonate, propylene carbonate) and their derivatives. This parameter change in the solvent system resolves the contradiction by enabling both good manufacturing simplicity and improved coloristic properties (color brilliance and strength) in the final dye product.
2Ease of manufacture
If the reaction is carried out with technical grade 1,4-dichloro-5,8-dihydroxyanthraquinone containing impurities, then the ease of manufacture improves, but the purity of the final product deteriorates
Solution Approach 1:
The patent introduces a specific base (alkali metal phosphate or ammonium phosphate) as an intermediary substance that facilitates the reaction. This intermediary enables the use of technical grade starting materials containing impurities while maintaining high product purity, as the base mediates the reaction conditions to favor formation of the desired phenylaminohydroxyanthraquinone product while leaving impurities in the mother liquor.
Solution Approach 2:
The patent changes the reaction parameters by specifying particular bases (tripotassium phosphate, trisodium phosphate, dipotassium hydrogen phosphate, disodium hydrogen phosphate, ammonium phosphate) and cyclic carbonate ester solvents. These parameter changes enable the process to tolerate technical grade starting materials while achieving >95% pure products with low residual amine content (<600 ppm).
3Ease of operation
If conventional bases from alkali phosphate series are used, then the ease of operation is good, but the coloristic properties and purity of the product deteriorate
Solution Approach 1:
The patent refines the base parameter selection to specific alkali metal phosphates (tripotassium phosphate, trisodium phosphate), dipotassium hydrogen phosphate, disodium hydrogen phosphate, or ammonium phosphate. This precise parameter specification improves both ease of operation and manufacturing precision by achieving superior coloristic properties (brilliance and strength) and high product purity while maintaining operational simplicity.
4Manufacturing precision
If the residual amine content is reduced below 600 ppm, then the purity of the product improves, but the manufacturing complexity increases
Solution Approach 1:
The patent uses specific bases (alkali metal phosphates or ammonium phosphate) as intermediaries that enable the achievement of low residual amine content (<600 ppm) without increasing manufacturing complexity. These bases mediate the reaction to ensure complete consumption of amine reactants while maintaining simple process conditions and avoiding the need for additional purification steps.
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 process delivers compounds with very good yields (>95%) and low residual amine content, exhibiting improved color brilliance and strength, suitable for advanced dye applications in plastics.
Implementation Method 1
A process for the preparation of phenylaminohydroxyanthraquinones by condensation of phenylamines with chlorohydroxyanthraquinones is known from EP-A 1 074 586
Data Source
AI summary
The new manufacturing process for 1,4-diphenylamino-5,8-dihydroxyanthraquinones yields these dyes with high color strength and excellent brilliance for coloring plastics.