Three-Subunit Stilbenedisulfonic Acid Fluorescent Whitening Agents
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Solution Overview
Problem
There is a continuous need to improve the effectiveness of fluorescent whitening agents (FWAs) for cellulosic materials, particularly for paper, as existing FWAs may not provide optimal whiteness and brightness.
Innovation Solution
Development of novel FWA compounds and mixtures containing three structural subunits derived from 4,4'-diamino-2,2'-stilbenedisulfonic acid, synthesized through a modified three-step process involving specific molar ratios of reactants, which include cyanuric chloride, aromatic amines, and secondary amines, to enhance whitening performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional FWAs with two subunits of 4,4'-diamino-2,2'-stilbenedisulfonic acid are used, then the synthesis process is relatively simple, but the whitening effectiveness is insufficient
Solution Approach 1:
The patent applies composite materials by creating FWA molecules with three subunits of 4,4'-diamino-2,2'-stilbenedisulfonic acid connected via triazine rings, combining multiple fluorescent chromophores in a single molecular structure. This composite approach enhances whitening effectiveness by providing multiple fluorescent centers that work synergistically to improve brightness and whiteness of cellulosic materials
Solution Approach 2:
The patent uses segmentation by dividing the FWA molecule into three distinct subunits of 4,4'-diamino-2,2'-stilbenedisulfonic acid, each capable of independent fluorescent activity. This segmented structure allows for optimized distribution of fluorescent centers along the molecular chain, improving overall whitening performance while maintaining synthetic feasibility through modular assembly
2Reliability
If the molar ratios of starting components are modified to create novel FWA compounds, then the whitening performance is improved, but the synthesis process requires more precise control
Solution Approach 1:
The patent applies parameter changes by systematically varying the molar ratios of cyanuric chloride, 4,4'-diamino-2,2'-stilbenedisulfonic acid, and amine components during synthesis. By optimizing these parameters, the patent achieves controlled formation of three-subunit structures with enhanced whitening performance, demonstrating that precise parameter control can be translated into superior product effectiveness
3Illumination intensity
If three subunits of 4,4'-diamino-2,2'-stilbenedisulfonic acid are incorporated into the FWA structure, then the optical whitening capability is enhanced, but the synthesis complexity increases
Solution Approach 1:
The patent applies universality by designing a synthetic route using cyanuric chloride as a universal coupling agent that can connect multiple subunits of 4,4'-diamino-2,2'-stilbenedisulfonic acid through standard nucleophilic substitution reactions. This multi-functional approach allows the same reaction methodology to be applied repeatedly to build the three-subunit structure, managing synthesis complexity through standardized chemical transformations
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 novel FWA compounds and mixtures demonstrate improved effectiveness in enhancing the whiteness and brightness of cellulose-based materials like paper, offering better optical whitening capabilities compared to traditional FWAs.
Implementation Method 1
Fluorescent whitening agents (FWAs), also called optical brighteners (OBAs), are well known and are widely used to improve the whiteness and brightness by treatment of cellulose-based materials
Data Source
AI summary
The invention relates to novel fluorescent whitening agents, compositions or mixtures thereof with known fluorescent whitening agents, their preparation, and their use. The novel fluorescent whitening agents contain three structural subunits derived from 4,4'-diamino-2,2'-stilbenedisulfonic acid. The novel compounds and their mixtures with known FWAs show very good effectiveness as fluorescent whitening agents for cellulosic materials, in particular for paper.