Oxidized Cellulose Production via Hypochlorous Acid Oxidation
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Solution Overview
Problem
Existing methods for producing nanocellulose using N-oxyl compounds like TEMPO result in residual toxicity concerns and inefficiencies due to excessive mechanical fibrillation requirements, as well as high costs associated with these catalysts.
Innovation Solution
Oxidizing cellulose raw materials using hypochlorous acid or its salt with an available chlorine concentration of 6-14% by mass, within a pH range of 5.0-14.0, to produce oxidized cellulose that can be fibrillated without mechanical treatment, eliminating the need for TEMPO and reducing toxicity and production costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If N-oxyl compounds like TEMPO are used as catalysts in the oxidation of cellulose, then the oxidation efficiency is improved, but residual N-oxyl compounds remain in the final product causing toxicity concerns and increasing production costs
Solution Approach 1:
The invention removes the harmful N-oxyl compound catalyst from the oxidation system entirely, replacing it with a chlorine-based oxidant system (sodium hypochlorite or calcium hypochlorite) that does not leave toxic residues in the final nanocellulose product
Solution Approach 2:
The invention substitutes expensive N-oxyl compound catalysts with inexpensive chlorine-based oxidants (sodium hypochlorite or calcium hypochlorite), significantly reducing production costs while eliminating the need for costly catalyst removal processes
2Ease of manufacture
If the carboxyl group content in oxidized cellulose is kept low (0.20-0.50 mmol/g), then the oxidation process is easier to control, but excessive mechanical fibrillation is required which reduces production efficiency
Solution Approach 1:
The invention changes the oxidation parameters by using chlorine-based oxidants with controlled available chlorine concentrations (5-15%) and adjusting pH levels (5-10) to achieve optimal carboxyl group content (0.3-2.0 mmol/g) that enables efficient fibrillation without excessive mechanical treatment
Solution Approach 2:
The invention performs preliminary oxidation treatment with chlorine-based oxidants to pre-modify the cellulose structure, introducing sufficient carboxyl groups before fibrillation to reduce the mechanical energy required for subsequent nanocellulose production
3Manufacturing precision
If excessive mechanical fibrillation is applied to produce nanocellulose, then the nanocellulose can be obtained, but the production process becomes inefficient and costly
Solution Approach 1:
The invention replaces excessive mechanical fibrillation with a chemical oxidation approach using chlorine-based oxidants, where the chemical modification of cellulose (introduction of carboxyl groups) facilitates easier and more efficient separation into nanocellulose with reduced mechanical energy input
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
This method enables efficient production of nanocellulose without residual N-oxyl compounds, reducing environmental and human toxicity risks while minimizing mechanical fibrillation, thus providing an economically viable and effective process.
Implementation Method 1
oxidizing a cellulose raw material with a hypochlorous acid or salt thereof having an available chlorine concentration of from 6% by mass to 14% by mass
Data Source
AI summary
Provided is an oxidized cellulose, a 13C solid-state NMR spectrum of the oxidized cellulose including a number of peaks in a range of from 165 ppm to 185 ppm, which can be produced by oxidizing a cellulose raw material with a hypochlorous acid or salt thereof having an available chlorine concentration of from 6% by mass to 14% by mass, while adjusting the pH in a range of from 5.0 to 14.0.