DHHB Solidification via High Shear Crystallization
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Solution Overview
Problem
The existing methods for solidifying hexyl 2-[4-(diethylamino)-2-hydroxybenzoyl]benzoate (DHHB) are economically inefficient and result in non-uniform particle shapes and sizes, leading to poor caking properties due to slow crystallization and lack of control over the process.
Innovation Solution
Applying a shear rate of at least 400 s^-1 to the liquid or subcooled DHHB melt, using apparatus such as extruders, scraped surface heat exchangers, or stirred vessels with scraping agitators, to accelerate crystallization and achieve uniform particle formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If conventional solidification methods (tubs or drums) are used for DHHB, then the process is simple to operate, but the crystallization is extremely slow (weeks) and space time yield is poor
Solution Approach 1:
The invention changes the physical parameter of shear rate by introducing mechanical agitation (stirring or extrusion) to the crystallization process. By applying a shear rate of at least 400 s⁻¹, the crystallization kinetics are dramatically accelerated from weeks to minutes or hours, thereby resolving the contradiction between ease of operation and productivity.
Solution Approach 2:
The invention employs periodic mechanical agitation (stirring or extrusion cycles) to induce and accelerate crystallization. This periodic application of shear stress promotes nucleation and crystal growth, transforming the extremely slow spontaneous crystallization into a controlled, rapid process that maintains operational simplicity while dramatically improving productivity.
2Device complexity
If conventional solidification methods are used for DHHB, then no special equipment is needed, but particle shapes and sizes are non-uniform and caking properties are poor
Solution Approach 1:
By changing the shear rate parameter to at least 400 s⁻¹ through mechanical agitation, the invention achieves uniform particle shapes and sizes. The controlled shear field promotes synchronized nucleation and crystal growth, resulting in particles with consistent morphology and improved flow properties, while avoiding the need for complex specialized equipment.
Solution Approach 2:
The invention applies preliminary mechanical agitation to the melt before complete solidification occurs. This preliminary action of applying shear stress during the liquid and early solidification stages establishes uniform crystal nucleation and growth patterns, ensuring consistent particle morphology is achieved throughout the solidification process without requiring complex post-processing equipment.
3Use of energy by moving object
If DHHB melt is allowed to crystallize slowly without agitation, then energy consumption is low, but crystallization takes weeks and remains in metastable liquid state
Solution Approach 1:
The invention employs periodic or continuous mechanical agitation at moderate energy input to trigger and accelerate crystallization. This periodic application of mechanical energy overcomes the metastable liquid state and promotes rapid crystal formation, reducing crystallization time from weeks to minutes or hours while consuming significantly less energy than alternative rapid solidification methods.
Solution Approach 2:
By changing the shear rate parameter through mechanical agitation, the invention dramatically accelerates the crystallization kinetics without requiring large increases in energy consumption. The mechanical energy input at shear rates ≥400 s⁻¹ efficiently promotes nucleation and crystal growth, resolving the contradiction between low energy consumption and excessive time loss.
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 process significantly accelerates the crystallization of DHHB, achieving uniform particle shapes and sizes, improving flowability and reducing solidification time to less than 2 hours, with complete solidification possible within minutes.
Implementation Method 1
applying a shear rate of at least 400 s-1 to a liquid or subcooled DHHB melt, wherein the applying of the shear rate accelerates the crystallization of DHHB
Data Source
AI summary
The present invention relates to a process for the solidification of hexyl 2-[4-(diethylamino)-2- hydroxybenzoyl]benzoate (INCI diethylamino hydroxybenzoyl hexyl benzoate, DHHB), wherein the process comprises a step (a) of applying a shear rate of at least 400 s-1 to liquid hexyl 2-[4-5 (diethylamino)-2-hydroxybenzoyl]benzoate.