Diamine Suspension Phosgenation via Dynamic Mixing
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Solution Overview
Problem
The production of high-melting organic diisocyanates from diamines like 1,5-naphthalenediamine, 1,4-phenylenediamine, tetraline diamine, and o-tolidine diamine with phosgene faces challenges such as by-product formation, incomplete reaction, and yield reduction due to the formation of coarse particles that are difficult to phosgenate, especially when the amines are sparingly soluble in inert solvents like chlorobenzene or o-dichlorobenzene.
Innovation Solution
A process involving the preparation of a suspension of diamines in inert solvents using dynamic mixing units like dispersing disks and rotor-stator systems, particularly rotor-stator systems like colloid mills and three-roll mills, to achieve a defined particle size distribution, which enhances the reaction efficiency and minimizes by-product formation by ensuring complete conversion to diisocyanates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If coarse particles are formed during suspension preparation, then mixing is simpler, but reaction completeness deteriorates and by-product formation increases
Solution Approach 1:
The patent changes the particle size parameter by using dynamic mixing units to reduce particle diameter to a specific range (0.1-10 μm). This parameter optimization ensures complete phosgenation reaction while maintaining manageable mixing conditions, resolving the contradiction between mixing simplicity and reaction completeness.
Solution Approach 2:
The patent replaces conventional static mixing methods with dynamic mixing units that use high-shear mechanical action to create fine suspensions. This mechanical substitution enables complete reaction by achieving uniform particle distribution and size reduction, overcoming the limitation of coarse particle formation in traditional mixing.
2Productivity
If dynamic mixing units are used to create fine suspensions, then reaction efficiency improves, but device complexity increases
Solution Approach 1:
The patent employs dynamic mixing units with movable components (rotors, stators, dispersing disks) that create high-shear zones for effective particle dispersion. The dynamic design enables fine suspension creation and complete reaction, achieving high productivity despite increased device complexity through controlled mechanical motion.
Solution Approach 2:
The mixing process is segmented into specific functional zones within the dynamic mixing unit, including high-shear zones for particle breakdown and circulation zones for uniform distribution. This segmentation of the mixing function improves reaction efficiency while organizing device complexity into manageable functional segments.
3Quantity of substance
If amine particles are not fully dissolved, then solvent usage is reduced, but phosgenation reaction completeness deteriorates
Solution Approach 1:
The patent applies preliminary action by pre-forming fine suspensions with controlled particle size (0.1-10 μm) before the phosgenation reaction. This preliminary suspension preparation ensures that amine particles are sufficiently dispersed and accessible to phosgene, enabling complete reaction without requiring excessive solvent for dissolution.
Solution Approach 2:
The patent changes the physical state parameter of the amine from undissolved coarse particles to fine suspended particles with specific size distribution. This parameter change maintains reduced solvent usage while enabling complete phosgenation by increasing the surface area and accessibility of amine particles to the reagent.
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 approach significantly reduces by-product formation, increases the yield of diisocyanates, and simplifies the purification process, allowing for a higher achievable capacity in isocyanate production while maintaining high purity and molecular weight distribution.
Implementation Method 1
using dynamic mixing units selected from dispersing disks and rotor-stator systems
Implementation Method 2
phosgenation of the diamine suspended in the inert solvent to obtain the respective diisocyanate
Data Source
AI summary
The invention relates to a method for producing organic diisocyanates by reacting the corresponding diamines with phosgene in inert solvents. High-melting diamines from the series of 1,5-naphthalenediamine, tetralindiamine, 1,4-phenylenediamine, durenediamine, and o-tolidinediamine are used as diamines. According to the invention, a suspension of the diamines in inert solvents is produced, wherein dynamic mixing units, selected from dispersion disks and rotor-stator systems, are used, and the obtained suspension is phosgenated.