US 12,305,006 B1
Methods for catalytically degrading polyolefin plastics at low temperatures
Huajie Yin, Hefei (CN); Tengxiu Tu, Hefei (CN); Yijin Wu, Hefei (CN); Haimin Zhang, Hefei (CN); and Guozhong Wang, Hefei (CN)
Assigned to HEFEI INSTITUTES OF PHYSICAL SCIENCE, CHINESE ACADEMY OF SCIENCES, Hefei (CN)
Filed by HEFEI INSTITUTES OF PHYSICAL SCIENCE, CHINESE ACADEMY OF SCIENCES, Anhui (CN)
Filed on Jan. 3, 2025, as Appl. No. 19/008,767.
Claims priority of application No. 202411027340.3 (CN), filed on Jul. 30, 2024.
Int. Cl. C08J 11/16 (2006.01)
CPC C08J 11/16 (2013.01) [C08J 2323/06 (2013.01); C08J 2323/12 (2013.01)] 10 Claims
 
1. A method for catalytically degrading polyolefin plastics at a low temperature, comprising:
S11, mixing anhydrous sodium chloride, anhydrous potassium chloride and anhydrous aluminum chloride to obtain a mixed salt, wherein a molar fraction of the anhydrous sodium chloride, the anhydrous potassium chloride and the anhydrous aluminum chloride are 17.5-25 mol %, 12.5-20 mol % and 57.5-68.5 mol % respectively,
grinding the mixed salt thoroughly and transferring into a reaction tube and sealing, heating the reaction tube to 120-150° C. until the mixed salt is completely melted into a clear and transparent liquid, cooling the reaction tube to a room temperature until the clear and transparent liquid re-solidifies into a solid, grinding the solid into powder to obtain molten salt catalyst 1; and
S12, mixing the molten salt catalyst 1 with pulverized polyolefin plastics in a mass ratio of (1-10):1 to obtain a mixture, adding KHCO3 to the mixture with an addition amount within a range of 2.5-20 wt % of a mass of the mixed salt, heating the mixture to 90-100° C., maintaining the temperature until the polyolefin plastics are fully degraded, and recovering the molten salt catalyst 1 after the mixture is cooled to the room temperature; or
S21, mixing the anhydrous sodium chloride, the anhydrous potassium chloride and the anhydrous aluminum chloride to obtain the mixed salt, wherein a molar fraction of the anhydrous sodium chloride, the anhydrous potassium chloride and the anhydrous aluminum chloride in the mixed salt are 17.5-25 mol %, 12.5-20 mol % and 57.5-68.5 mol % respectively, adding KHCO3 to the mixed salt and grinding thoroughly, and transferring into a reaction tube and sealing, wherein an addition amount of KHCO3 is within a range of 2.5-20 wt % of the mass of the mixed salt,
heating the reaction tube to 120-150° C. until the mixed salt with KHCO3 added is completely melted into a clear and transparent liquid, cooling the reaction tube to the room temperature until the clear and transparent liquid re-solidifies into a solid, grinding the solid into powder to prepare molten salt catalyst 2; and
S22, mixing the molten salt catalyst 2 with the pulverized polyolefin plastics in a, mass ratio of (1-10):1 to obtain a mixture, heating the mixture to 90-100° C., maintaining the temperature until the polyolefin plastics are fully degraded, and recovering the molten salt catalyst 2 after the mixture is cooled to the room temperature.