DOG Crystallization Process for Particle Size Control
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Solution Overview
Problem
Conventional methods for producing 2-(5-ethyl-5-hydroxymethyl-1,3-dioxane-2-yl)-2-methylpropane-1-ol (DOG) result in small particle size crystals, leading to inefficient solid-liquid separation, high risk of dust explosion, and low trans-isomer purity, requiring additional purification steps that are industrially disadvantageous.
Innovation Solution
A process involving the reaction of hydroxypivalaldehyde and trimethylolpropane in the presence of an acid catalyst, followed by neutralization, heating, and controlled cooling to increase particle size and trans-isomer purity without additional purification steps, using specific solvent and catalyst conditions to regulate the reaction and recrystallization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional acetalization method is used to produce DOG, then DOG can be obtained, but the particle size of DOG crystals becomes extremely small (10 μm or less), leading to inefficient solid-liquid separation and high dust explosion risk
Solution Approach 1:
The patent applies parameter changes by optimizing the water content in the reaction system to 5-20 mass% and controlling the cooling rate to 0.1-5°C/min. These parameter adjustments directly influence the crystal growth kinetics, producing DOG crystals with particle sizes of 50 μm or more while maintaining high trans-isomer purity, thereby resolving the contradiction between crystal size and separation efficiency
Solution Approach 2:
The patent employs periodic action through controlled cooling at specific rates (0.1-5°C/min) after the acetalization reaction. This controlled periodic cooling allows gradual crystal growth and orderly arrangement of molecules, resulting in larger crystal particles that are easier to separate and handle, thus improving solid-liquid separation efficiency without sacrificing purity
2Manufacturing precision
If conventional acetalization method is used to produce DOG, then DOG can be obtained, but the trans-isomer purity becomes insufficient, requiring additional purification steps
Solution Approach 1:
The patent achieves high trans-isomer purity (99% or more) by optimizing reaction parameters including water content (5-20 mass%) and cooling rate (0.1-5°C/min). These parameter controls favor the formation of the trans-isomer during crystallization, eliminating the need for additional purification steps such as recrystallization, thereby reducing device complexity while maintaining high purity
Solution Approach 2:
The patent implements self-service through selective crystallization where the trans-isomer preferentially crystallizes from the reaction mixture under controlled conditions. The crystallization process itself serves as the purification mechanism, with the trans-isomer automatically separating from the cis-isomer in the mother liquor, eliminating the need for external purification operations
3Manufacturing precision
If conventional acetalization method is used to produce DOG, then DOG can be obtained, but the crystal particle size remains small, making handling difficult and increasing dust explosion risk
Solution Approach 1:
The patent reduces dust explosion risk by changing physical parameters to produce larger crystals (50 μm or more). The controlled cooling rate and water content optimization promote growth of larger, less dusty particles that are less prone to becoming airborne and igniting, thereby mitigating the harmful dust explosion factor while maintaining manufacturing precision
Solution Approach 2:
The patent converts the potential harm of fine particles into a benefit by controlling crystallization to produce larger particles. The controlled cooling process transforms what would be fine, dangerous dust into larger, safer crystals that are easier to handle and less prone to explosion, turning a harmful characteristic into a beneficial one
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
Produces DOG with larger crystal particle size, high trans-isomer purity, and improved handling and safety, reducing the risk of dust explosion, while maintaining high yield and purity, making it suitable for industrial use as a raw material for polymer and chemical products.
Implementation Method 1
heating the reaction product liquid after the neutralization to 70° C. or higher, thereby completely or partly dissolving crystals of the dioxane glycol
Implementation Method 2
cooling the reaction product liquid after the heating to 60° C. or lower, thereby allowing the dissolved dioxane glycol to recrystallize
Implementation Method 3
allowing the dissolved dioxane glycol to recrystallize
Data Source
AI summary
A production method of 2-(5-ethyl-5-hydroxymethyl-1,3-dioxane-2-yl)-2-methylpropane-1-ol (DOG) which includes a step of acetalizing hydroxypivalaldehyde with trimethylolpropane in a solvent in the presence of an acid catalyst. After the acetalization, the reaction product liquid is neutralized and then heated to dissolve the deposited DOG crystals. Then, the reaction product liquid is cooled to recrystallize DOG. DOG produced in such manner has an adequately large particle size. Therefore, DOG is easy to handle and involves little danger of dust explosion.