Tetraalkylammonium Acetate Solvent for Cellulose Dissolution
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Solution Overview
Problem
Current methods for dissolving cellulose, such as N-methylmorpholine-N-oxide/water and lithium chloride/N,N-dimethylacetamide, require high temperatures, special pretreatments, and often lead to decomposition or reduced strength, limiting industrial applications due to safety concerns and processability issues.
Innovation Solution
A solvent system comprising tetraalkylammonium acetate and an aprotic polar solvent, like N,N-dimethylacetamide, that can uniformly dissolve cellulose within a short time at room temperature without pretreatment, maintaining the polysaccharide's strength and allowing for excellent forming processability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If N-methylmorpholine-N-oxide/water mixed solvent is used to dissolve cellulose, then cellulose can be directly dissolved without chemical change, but the solvent needs to be heated to around 130°C and may detonate at about 150°C, involving danger
Solution Approach 1:
The patent changes the chemical composition parameters of the solvent system by replacing N-methylmorpholine-N-oxide with tetraalkylammonium acetate combined with aprotic polar solvents. This parameter change maintains the dissolution capability while eliminating the detonation hazard associated with the original solvent system.
Solution Approach 2:
The patent employs a solvent system that can be easily prepared and used without the need for specialized safety infrastructure. The tetraalkylammonium acetate and aprotic polar solvent combination provides a safer, more readily usable alternative to the hazardous N-methylmorpholine-N-oxide system.
2Ease of manufacture
If cellulose is heated at 100°C or more for a long time period or swollen by being immersed in water or an alcohol for a long time period, then cellulose can be dissolved, but it is difficult to dissolve the cellulose simply and the molecular chain of the cellulose may be cleaved which leads to reduce its strength
Solution Approach 1:
The patent changes the dissolution conditions by using tetraalkylammonium acetate with aprotic polar solvents at room temperature or mild temperatures. This eliminates the need for prolonged heating or swelling treatments, thereby preventing molecular chain cleavage and preserving cellulose strength.
Solution Approach 2:
The tetraalkylammonium acetate acts as an intermediary substance that facilitates cellulose dissolution without requiring extreme conditions. It mediates between the cellulose and the aprotic polar solvent, enabling dissolution at mild conditions that preserve the polymer chain integrity.
3Ease of manufacture
If a high-concentration aqueous solution of sodium thiocyanate is used to dissolve cellulose, then type II cellulose or amorphous cellulose can be dissolved, but the solvent system cannot be applied to a natural-type cellulose and a heating step at 100°C or more is needed which may reduce the strength
Solution Approach 1:
The patent creates a universal solvent system using tetraalkylammonium acetate and aprotic polar solvents that can dissolve all types of cellulose (natural-type, type II, and amorphous) without requiring pretreatment. This multi-functional solvent system eliminates the limitations of sodium thiocyanate solutions.
Solution Approach 2:
The patent changes the solvent composition parameters to achieve broad applicability. The combination of tetraalkylammonium acetate with various aprotic polar solvents creates a versatile system that works across different cellulose crystallinity levels and types without requiring heating or pretreatment.
4Ease of manufacture
If an imidazolium-based ionic liquid is used to dissolve cellulose, then high cellulose-dissolving power is achieved, but the cellulose solution has a high viscosity and is liable to gel, involving a problem in terms of forming processability
Solution Approach 1:
The patent changes the solvent system parameters by replacing ionic liquids with tetraalkylammonium acetate and aprotic polar solvents. This parameter change maintains high dissolution capability while dramatically reducing solution viscosity and gelation tendency, thereby improving forming processability.
Solution Approach 2:
The patent uses a composite solvent system combining tetraalkylammonium acetate with aprotic polar solvents. This composite approach achieves the dissolution power of ionic liquids while avoiding their detrimental viscosity and gelation effects, enabling better processing.
5Ease of manufacture
If amino base is added to ionic liquid to improve cellulose solubility, then the liquid expresses cellulose solubility, but the solubility is limited and the addition of amino base may decompose the cellulose
Solution Approach 1:
The patent replaces the complex ionic liquid system requiring amino base additives with a simpler tetraalkylammonium acetate and aprotic polar solvent system. This simpler system achieves equal or better solubility without risking cellulose decomposition, eliminating the need for additive management.
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 solvent system improves solubility and dissolution rate of cellulose, reduces viscosity, and enables the production of polysaccharide derivatives with enhanced properties like water resistance and thermoplasticity, facilitating the creation of formed articles like fibers and films.
Implementation Method 1
A solvent system comprising tetraalkylammonium acetate and an aprotic polar solvent, like N,N-dimethylacetamide, that can uniformly dissolve cellulose within a short time at room temperature without pretreatment
Data Source
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AI summary
There is provided a solvent that can uniformly dissolve a polysaccharide within a short time period regardless of the crystal form of the polysaccharide and without requiring any special pretreatment. The solvent includes a tetraalkylammonium acetate represented by the below-indicated formula; and an aprotic polar solvent. A content of the aprotic polar solvent is 35 wt% or more. In the formula, R1, R2, R3, and R4 each independently represent an alkyl group having 3 to 6 carbon atoms.