Polylactic acid producing process
A production process and technology for polylactic acid, applied in the field of preparing polylactic acid, can solve the problems of complex reaction process, long production cycle, low yield, etc., and achieve the effects of reducing reaction conditions, shortening production process, and easy control of production process
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Embodiment 1
[0019] Add 1000kg of L-lactic acid and 1kg of strontium-aluminum composite catalyst system catalyst into the reactor, heat to 250°C, the vacuum degree in the reactor is 1500Pa, react for 5h, and fully remove the water to obtain a polymer with a degree of polymerization of 5-20. Lactic acid oligomer 700KG. After the reaction product is purified by solution, 660KG of pure lactic acid oligomers can be obtained.
[0020] After mixing pure lactic acid oligomers and 66g of strontium and aluminum composite catalyst system catalyst in the reactor, replace the air in the reactor with nitrogen, maintain positive pressure, stir and heat to 250°C, Control the pressure at normal pressure, react for 10 hours, and obtain a reaction product containing polylactic acid. After the single treatment, 654 kg of polylactic acid with a molecular weight of about 400,000 can be obtained, and the yield of polylactic acid is above 99%.
Embodiment 2
[0022] Add 1000kg of L-lactic acid and 10kg of strontium-aluminum composite catalyst system catalyst into the reactor, heat to 100°C, the vacuum degree in the reactor is 4500Pa, react for 5h, and fully remove the water to obtain The reaction product of lactic acid oligomers between them is 700KG, and 660KG of pure lactic acid oligomers can be obtained after the reaction product is purified by solution.
[0023] Put the pure lactic acid oligomer and 660g of strontium, aluminum composite catalyst system catalyst into the reactor and mix, replace the air in the reactor with helium, keep the positive pressure, stir and heat to 120°C, the reactor Control the pressure at normal pressure and react for 8 hours to obtain a reaction product containing polylactic acid. After single treatment, 654 kg of polylactic acid with a molecular weight of about 100,000 can be obtained, and the yield of polylactic acid is above 99%.
Embodiment 3
[0025] Add 1000kg of L-lactic acid and 5kg of strontium-aluminum composite catalyst system catalyst into the reactor, heat to 200°C, the vacuum degree in the reactor is 6000Pa, react for 4.5h, and after fully removing water, obtain The reaction product of 20 lactic acid oligomers is 700KG, and the reaction product can be purified by solution to obtain 660KG of pure lactic acid oligomers.
[0026] Put the pure lactic acid oligomer and its 330g strontium-aluminum composite catalyst system catalyst into the reactor and mix them, replace the air in the reactor with neon, keep the positive pressure, stir and heat to 130°C, react The pressure inside the vessel is controlled at normal pressure, and the reaction product containing polylactic acid is obtained after 10 hours of reaction. After the single-off treatment, 654 kg of polylactic acid with a molecular weight of about 350,000 can be obtained, and the yield of polylactic acid is above 99%.
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