Bleaching of substrates

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Solution Overview

Problem

Existing methods for bleaching substrates, such as cellulosic materials and crockery, require high levels of manganese transition metal catalysts and are inefficient at high pH levels, limiting their effectiveness and practicality.

Innovation Solution

A method using a preformed manganese transition metal catalyst in an aqueous medium with a pH range of 11 to 13 and a concentration of 0.0001 to 1.5 microM, specifically a dinuclear Mn(II)Mn(II), Mn(II)Mn(III), Mn(III)Mn(III), Mn(III)Mn(IV), or Mn(IV)Mn(IV) catalyst with a ligand of formula (I), effectively bleaches substrates at minimal catalyst levels.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If high levels of manganese transition metal catalyst are used for bleaching substrates, then bleaching effectiveness is improved, but catalyst cost and complexity increase

Engineering Contradiction:

Improvebleaching effectivenessVSAvoidcatalyst concentration

Core Design Contradiction:

ReliabilityVSQuantity of substance

Solution Approach 1:

The patent changes the pH parameter to alkaline conditions (pH 11-13) where the manganese catalyst exhibits maximum activity. This parameter change allows the catalyst to achieve optimal bleaching effectiveness at very low concentrations (0.0001 to 1.5 microM), resolving the contradiction between effectiveness and quantity required

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent uses a preformed manganese transition metal catalyst that is prepared in advance with optimal structure and oxidation state. This preliminary preparation ensures the catalyst is immediately active upon contact with the substrate-hydrogen peroxide system, maximizing bleaching efficiency at minimal catalyst levels

Inventive Principle:

Principle #10Preliminary action

2Productivity

If high pH levels are used for bleaching with manganese catalyst, then catalyst activity is improved, but catalyst stability deteriorates

Engineering Contradiction:

Improvecatalyst activityVSAvoidcatalyst stability

Core Design Contradiction:

ProductivityVSStability of the object's composition

Solution Approach 1:

The patent introduces a stabilizing ligand structure (me 3 -tacn or me 4 -dtne) that acts as an intermediary between the manganese catalyst and the alkaline environment. This ligand mediates the interaction by providing a stable coordination sphere that protects the catalyst from degradation at high pH while maintaining its catalytic activity

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent creates a composite catalyst system consisting of manganese ion coordinated with me 3 -tacn or me 4 -dtne ligands. This composite structure combines the catalytic properties of manganese with the stabilizing properties of the ligand, enabling the catalyst to function effectively at high pH levels without losing stability

Inventive Principle:

Principle #40Composite materials

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 achieves significant bleaching effects with very low levels of catalyst, increasing brightness and whiteness of substrates like softwood and eucalyptus pulp, and raw cotton, even at pH 11.0-13.0, demonstrating improved efficiency and cost-effectiveness.

Implementation Method 1

the transition metal catalyst is preformed and a dinuclear Mn(II)Mn(II), Mn(II)Mn(III), Mn(III)Mn(III), Mn(III)Mn(IV) or Mn(IV)Mn(IV) transition metal catalyst

Methodology Applied

Scientific EffectCatalysis: Catalysis