KR970042468A - Separation and recovery method of waste polyester oligomer - Google Patents

Abstract

The present invention relates to a method for separating and recovering waste polyester oligomers, and more specifically, to 20 parts by weight of alcohol and 0.01 to 10 parts by weight of catalyst based on 100 parts by weight of waste polyester oligomer, followed by a nitrogen atmosphere. Under a reaction temperature of 120 to 300 ° C. for 30 minutes to 15 hours to completely separate and decompose into dimethyl terephthalic acid (DMT), ethylene glycol (EG), methylhydroxyethyl terephthalate (MHET), and organic and inorganic impurities, A method for separating and recovering waste polyester oligomer to be recovered.

Description

Separation and recovery method of waste polyester oligomer

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Claims (11)

20 to 300 parts by weight of alcohol and 0.01 to 10 parts by weight of the catalyst are mixed with respect to 100 parts by weight of the waste polyester oligomer, and then reacted for 30 minutes to 15 hours at a reaction temperature of 120 to 300 ° C. under a nitrogen atmosphere to obtain dimethyl terephthalic acid (DMT ), Ethylene glycol (EG), methyl hydroxyethyl terephthalate (MHET), and separation and recovery of waste polyester oligomers, characterized in that they are completely decomposed and recovered with organic and inorganic impurities. The method of claim 1, wherein the alcohol is methanol, ethanol, propanol, butanol, phenol, cresol or benzyl alcohol. The method for separating and recovering spent polyester oligomer according to claim 1 or 2, wherein the alcohol is methanol. The method of claim 1, wherein the solvent is a Lewis acid catalyst such as zinc chloride, iron chloride, aluminum chloride or mercury chloride, carboxylic acid catalyst such as acetic acid, formic acid, propionic acid, butyric acid or benzoic acid, magnesium acetate, calcium acetate, zinc acetate, acetic acid Acetic acid inorganic catalysts such as sodium or phosphorus acetate, methylene sulfonic acid, ethylene sulfonic acid, propylene sulfonic acid, butylene sulfonic acid, pentylene sulfonic acid, hexylene sulfonic acid, heptylene sulfonic acid octylene sulfonic acid and other saturated aliphatic sulfonic acids, trifluoride sulfonic acid, trichloride sulfonic acid, sulfonic acid catalysts such as p-toluene sulfonic acid, cyclohexane sulfonic acid benzene sulfonic acid or pyrosulfonic acid, methylene sulfonic acid, ethylene sulfonic acid propylene sulfonic acid, butylene sulfonic acid, pentylene sulfonic acid, hexylene sulfonic acid, heptylene sulfonic acid, octane sulfonic acid Methylene sulfonic acid and other saturated aliphatic sulfonic acids, hemp One from the group consisting of sulfonic acid catalysts such as sulfonic acid fluoride, sulfonic acid trichloride, p-toluene sulfonic acid, cichloro sulfonic acid, benzene sulfonic acid and alkali catalysts such as sodium carbonate, sodium carbonate, calcium hydroxide or sodium hydroxide The method for separating and recovering spent polyester oligomers, characterized in that more than that is selected. The method of claim 1, wherein the inorganic impurities are removed by a filter press in a liquid reactant or the alcohol is evaporated in the reactants, and then an organic solvent is added to DMT, EG, MHET, inorganic and organic impurities in a slurry state. The reaction product separated by filtration, centrifugation or layer separation, or the reaction product obtained by washing the liquid reactant directly or two to four times with methanol is separated by filtration or centrifugation into a liquid phase and a solid phase, and then filtered by adding an organic solvent to a solid phase. Separation and recovery of waste polyester oligomer, characterized in that separated by centrifugation or filter press method. The waste polyester according to claim 5, wherein the organic solvent is methyl ethyl ketone, ethyl ether, acetone, ethylene dichloride, carbon tetrachloride, benzene, ethyl acetate, butyl acetate, chloroform, toluene, ethylenediamine or dioxane. Method for Separation and Recovery of Oligomers. The method of claim 5, wherein the EG and the organic solvent is separated from the liquid phase or a mixture of DMT, EG, MHET, organic impurities and organic solvent by distillation or distillation under reduced pressure. 8. The method of claim 7 wherein the MHET is separated by dissolving with a polar solvent from a mixture of DMT, MHET and organic impurities. The method according to claim 8, wherein the separated MHET is added to a pressurized reactor together with methanol to add the catalyst to about 5 parts by weight or less, or the reaction temperature is raised to 100 to 230 ° C without adding the catalyst for 30 minutes to 20 hours. A method for separating and recovering spent polyester oligomers, characterized in that the reaction is carried out for a period of time to separate and recover DMT and EG. 9. The method of claim 8, wherein the DMT and the organic impurities are separated by washing the organic impurities with aliphatic hydrocarbons such as pentane, hexane, heptane, octane or nonane. The method of claim 5, wherein when the inorganic impurity is removed by the filter press, the DMT is recovered by a recrystallization method.