Bleaching Catalyst Granules for Stable Low-Color Manganese Dosing
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Solution Overview
Problem
Existing bleaching formulations face challenges in achieving accurate dosing and homogeneous distribution of manganese catalysts, leading to underdosing or overdosing, and manganese salts used in these formulations are either intensely colored or unstable in alkaline environments, affecting bleaching performance and storage stability.
Innovation Solution
The use of protonated cyclic triamine compounds, such as 1,4,7-triazacyclononane, combined with Mn(II) oxalate and a polysaccharide absorbent, forms colorless or palely colored granules that maintain high bleaching activity and stability during storage, even in alkaline conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If Mn(II) salts are used as bleaching catalysts, then high bleaching activity is achieved, but the granules become intensely colored (red/pink)
Solution Approach 1:
The patent uses a ligand (triene or triazole derivative) as an intermediary substance that binds to Mn(II) ions to form a complex. This ligand acts as a mediator between the Mn(II) salt and the bleaching agent, modifying the electronic structure of the manganese complex to reduce its color intensity while maintaining catalytic activity. The ligand field theory explains that the specific arrangement of ligands around the metal ion affects the d-orbital splitting and thus the color of the complex.
Solution Approach 2:
The patent changes the chemical parameters of the manganese complex by selecting specific ligands with particular electronic properties. By adjusting the ligand type, stoichiometry, and coordination geometry, the optical properties (color) of the complex are modified. The patent specifies ligands with certain structural features (conjugated systems, heteroatoms) that influence the HOMO-LUMO gap and thus the absorption spectrum of the complex.
2Power
If Mn(II) salts are used in alkaline oxidative environments, then bleaching performance is improved, but storage stability deteriorates due to formation of brown MnO2
Solution Approach 1:
The patent applies preliminary protective action by pre-coating the Mn(II) salt with a ligand to form a stable complex before exposure to alkaline oxidative conditions. This pre-formed complex resists oxidation to MnO2 during storage. The ligand creates a protective shell around the Mn(II) ion, preventing direct contact with oxidizing agents and base, thus preventing the harmful oxidation reaction that would otherwise occur during storage.
Solution Approach 2:
The ligand serves as a protective intermediary between the Mn(II) salt and the harsh alkaline oxidative environment. It mediates the interaction by providing a stable coordination sphere that protects the manganese ion from premature oxidation. The ligand's electronic and steric properties create a kinetic barrier to oxidation, allowing the Mn(II) complex to remain stable during storage while still being active for bleaching when activated.
3Power
If small amounts of manganese catalyst (less than 0.1 wt %) are used, then bleaching efficiency is improved, but dosing accuracy and homogeneous distribution become difficult to achieve
Solution Approach 1:
The patent merges the manganese catalyst with the granule matrix by incorporating the Mn(II) ligand complex into the granule structure along with the bleaching agent and other detergent components. This integration ensures that the catalyst is uniformly distributed throughout the granule at the molecular level, eliminating dosing inaccuracies. The granule acts as a single integrated unit where the catalyst cannot segregate, ensuring consistent performance.
Solution Approach 2:
The patent achieves homogeneous distribution of the manganese catalyst by forming a molecular complex between Mn(II) and the ligand, which then incorporates uniformly into the granule matrix. The complex formation ensures molecular-level mixing, and the granulation process maintains this homogeneity. This approach eliminates the problems of catalyst aggregation and uneven distribution that occur with simple physical mixing of catalyst powders.
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 granules provide high bleaching activity and storage stability, ensuring consistent performance without the need for precise dosing and minimizing color issues, while maintaining effectiveness in detergent and dishwashing applications.
Implementation Method 1
The granules and formulations comprising said granules are suitable for use in catalysing oxidation or bleaching
Implementation Method 2
The granules are formed from a mixture comprising a polysaccharide absorbent, Mn(II) oxalate, and a salt of formula (I)
Data Source
AI summary
The present invention concerns a granule comprising Mn(II) oxalate, a protonated salt of a cyclic triamine, a polysaccharide absorbent and a coating agent. In another embodiment the invention concerns a granule comprising a polysaccharide absorbent, a protonated salt of a cyclic triamine and no or very small amounts of Mn. The invention also concerns methods of preparing said granules comprising Mn(II) oxalate, polysaccharide absorbent and such salts or comprising polysaccharide absorbent, such salts and no Mn compound and bleaching formulations comprising the granules and a peroxy compound or a precursor thereof. Granules comprising Mn(II) oxalate, polysaccharide absorbent and the salt or comprising polysaccharide absorbent, the salt and no Mn compound, and formulations comprising these are suitable for use in catalysing oxidation, for example as a component of a dishwasher bleaching composition. The invention further relates to methods of oxidising with the bleaching formulations described herein.