Molten Lactide Complex Formation Without Ring-Opening
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Solution Overview
Problem
Existing methods for producing lactides are limited to ring-opening polymerization, which restricts their use as synthetic raw materials for biodegradable polymers, and there is a need for a novel method to create lactide complexes without ring-opening.
Innovation Solution
A method involving heating a mixture of molten lactide with a low-molecular-weight substance under controlled conditions to react without ring-opening, using lactides like L-lactide, D-lactide, or DL-lactide, and low-molecular-weight substances with molecular weights of 2000 or less, while stirring and removing unreacted materials with an aqueous solvent.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If ring-opening polymerization is used to produce lactides, then biodegradable polymers can be synthesized, but the lactide structure is opened and lost
Solution Approach 1:
The invention changes the reaction parameters by using molten lactide (above melting point) instead of solution phase, and controlling temperature (80-180°C) and pressure (5-300 mmHg reduced pressure) to achieve complex formation without ring-opening polymerization. This parameter optimization allows the lactide cyclic structure to be maintained while still enabling reaction with low-molecular-weight substances.
Solution Approach 2:
The invention utilizes the phase transition of lactide from solid to molten state. By heating lactide above its melting point to create a molten state, the invention enables direct reaction with low-molecular-weight substances while maintaining the cyclic structure, avoiding the need for ring-opening polymerization that would destroy the cyclic structure.
2Productivity
If conventional ring-opening polymerization catalysts are used, then polymerization can proceed, but the reaction requires complex catalyst systems
Solution Approach 1:
The invention extracts and eliminates the need for complex ring-opening polymerization catalyst systems (organolithium, organopotassium, organozinc, organomagnesium, organotin, organocalcium, organotitanium, and amine catalysts). By using molten lactide and applying reduced pressure, the invention achieves reaction with low-molecular-weight substances without requiring these complex catalyst systems, thereby simplifying the overall process.
3Speed
If lactide is heated to high temperature, then reaction rate increases, but ring-opening polymerization may occur
Solution Approach 1:
The invention applies periodic control of temperature and pressure conditions. By maintaining temperature in the range of 80-180°C and applying reduced pressure (5-300 mmHg) in a controlled manner, the invention achieves adequate reaction rates while preventing unwanted ring-opening polymerization. The periodic removal of byproducts under reduced pressure also helps maintain the cyclic structure.
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 method produces novel lactide complexes that are insoluble or scarcely soluble in water, maintaining their cyclic structure and increasing yield, as evidenced by IR and mass spectra analysis.
Implementation Method 1
heating a mixture of the molten lactide with a low-molecular-weight substance to react the molten lactide with the low-molecular-weight substance without ring-opening of the lactide
Implementation Method 2
the mixture is stirred in the reaction step
Implementation Method 3
the method comprises a removal step of removing unreacted lactide and unreacted low-molecular-weight substance with an aqueous solvent after the reaction step
Data Source
AI summary
A method for producing a lactide complex is provided. A lactide complex is produced using a lactide which is a cyclic dimer of lactic acid by heating a mixture of the lactide in a molten state with a low-molecular-weight substance to react the molten lactide with the low-molecular-weight substance without ring-opening of the lactide.