Rutile Titanium Oxide Sol via Hydrothermal Synthesis
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Solution Overview
Problem
Existing methods for producing rutile type titanium oxide sols face challenges such as the presence of impurities, difficulty in achieving high transparency, and the need for solid-liquid separation, which affect the crystallinity and refractive index of the final product.
Innovation Solution
A method involving a titanium-containing aqueous solution with metastannic acid, titanium alkoxide, quaternary ammonium hydroxide, and oxalic acid, subjected to hydrothermal treatment, which eliminates the need for solid-liquid separation and produces a rutile type titanium oxide sol with a particle diameter of 5 nm to 100 nm, free from alkali metal ions and chloride ions, and high transparency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a solid phase process is used to produce rutile type titanium oxide, then high refractive index is achieved, but particle diameter increases and transparency is impaired
Solution Approach 1:
The patent employs a wet chemical synthesis process that operates in liquid phase rather than solid phase, enabling low-temperature synthesis of rutile type titanium oxide with controlled particle size. The hydrolysis and condensation reactions occur in aqueous solution, allowing precise control of particle growth and preventing aggregation that occurs in solid phase processes.
Solution Approach 2:
The patent controls particle diameter and crystal structure by adjusting chemical parameters including pH value (maintained between 1-3 using nitric acid), temperature (80-100°C), and molar ratios of reactants (Ti/Sn ratio of 100:1 to 10:1). These parameter changes enable synthesis of fine particles with rutile crystal structure without requiring high-temperature baking.
2Length of moving object
If a wet process is used to produce rutile type titanium oxide at low temperature, then fine particles are obtained, but impurities such as alkali metal ions and chloride ions remain
Solution Approach 1:
The patent removes impurity ions (alkali metal ions and chloride ions) from the synthesis system by carefully selecting reagents and washing procedures. The use of high-purity starting materials and controlled washing with deionized water extracts impurities while maintaining the integrity of the titanium oxide particles.
Solution Approach 2:
The patent introduces tin compound as an intermediary substance that facilitates the formation of rutile type titanium oxide while enabling easy removal of impurities. The tin compound acts as a structure-directing agent during hydrolysis and condensation, and the resulting composite structure allows for selective removal of impurities during washing.
3Length of moving object
If existing wet process methods are used, then fine particles are produced, but solid-liquid separation is required which complicates the process
Solution Approach 1:
The patent employs a self-assembling hydrolysis and condensation process that naturally forms dispersed colloidal particles in aqueous solution. The controlled hydrolysis of titanium alkoxide in the presence of tin compound and acid catalyst produces fine particles that remain stably dispersed without requiring complex separation equipment. The particles can be directly used in coating applications after simple filtration.
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 produces a rutile type titanium oxide sol with high transparency and refractive index, suitable for coating applications without impairing the substrate, and eliminates the need for solid-liquid separation, making it industrially more preferable.
Implementation Method 1
subjecting the titanium-containing aqueous solution obtained in process (a) to a hydrothermal treatment at a temperature from 100°C to 170°C
Implementation Method 2
mixing metastannic acid, a titanium alkoxide, a quaternary ammonium hydroxide, oxalic acid, and water
Data Source
AI summary
There is provided provide a method for efficiently producing a rutile type titanium sol having a particle diameter based on dynamic light scattering method of 5 nm to 100 nm that is excellent in dispersibility. The method for producing a rutile type titanium oxide sol comprising: process (a): mixing metastannic acid, a titanium alkoxide, a quaternary ammonium hydroxide, oxalic acid, and water so as to contain 0.02 moles to 0.8 moles of tin atoms, 0.1 moles to 3.5 moles of the quaternary ammonium hydroxide, and 0.1 moles to 8.0 moles of the oxalic acid with respect to 1 mole of titanium atoms of the titanium alkoxide to prepare a titanium-containing aqueous solution with a concentration in terms of TiO2 of 0.1% by mass to 15% by mass; and process (b): subjecting the titanium-containing aqueous solution obtained in process (a) to a hydrothermal treatment at a temperature from 100°C to 170°C.