Method for preparing diesel oil by catalyzing polyethylene degradation through aluminum oxide loaded transition metal catalyst

Abstract

The invention relates to the technical field of polymer degradation, in particular to a method for preparing diesel oil by catalyzing polyethylene degradation through an aluminum oxide loaded transition metal catalyst. The method for preparing diesel oil by catalyzing polyethylene degradation with the aluminum oxide-loaded transition metal catalyst comprises the following steps: uniformly mixing polyethylene and the aluminum oxide-loaded palladium catalyst, reacting at 150-180 DEG C for 3-8 hours, and carrying out solid-liquid separation, thereby obtaining the diesel oil. According to the method for preparing the diesel oil by catalyzing the polyethylene degradation by using the aluminum oxide loaded transition metal catalyst as the catalyst, the corresponding catalyst is utilized, the reaction under high pressure is not needed, the reaction temperature is relatively mild, the implementation condition is simple, the energy is saved, and the method can be popularized in a large range. According to the method for preparing the diesel oil by catalyzing polyethylene degradation by using the aluminum oxide loaded transition metal catalyst as the catalyst, the molecular length range of components in the prepared diesel oil is relatively concentrated, impurities are fewer, and the oil product is better.

Description

Technical Field

[0001] The present application relates to the technical field of polymer degradation, and in particular to a method for preparing diesel by catalyzing the degradation of polyethylene using an aluminum oxide-loaded transition metal catalyst. Background Art

[0002] Polyethylene is one of the commonly used polymer materials in daily life. It is widely used in the manufacture of daily necessities such as plastic bags and plastic films, and its application scale is getting larger and larger. Although polyethylene products are easy to use, due to the structural characteristics of polyethylene such as long chains and hydrophobic macromolecules, the degradation cycle of polyethylene is very long, and the degradation process in the natural environment is extremely slow. After years of natural degradation, only a small proportion of polyethylene is degraded. The degradation of polyethylene has become an environmental issue of concern to all countries.

[0003] At present, the degradation of polyethylene is mainly focused on shortening the degradation cycle, such as using microbial degradation, to speed up the degradation rate and reduce the impact on nature.

[0004] In recent years, new ideas have emerged for the degradation of polyethylene. Degrading polyethylene to produce diesel is one of the most important degradation technologies. Degrading waste polyethylene to obtain diesel can not only quickly process polyethylene waste, but also increase energy materials. However, when polyethylene is currently degraded, the diesel oil produced is of poor quality due to catalysts and other reasons. Summary of the invention

[0005] In order to improve the oil quality of diesel prepared by degrading polyethylene, the present application provides a method for preparing diesel by catalyzing the degradation of polyethylene using an aluminum oxide-loaded transition metal catalyst.

[0006] The present application provides a method for preparing diesel by catalyzing the degradation of polyethylene with an aluminum oxide-supported transition metal catalyst, which adopts the following technical solution: A method for preparing diesel by catalyzing the degradation of polyethylene with an aluminum oxide-loaded transition metal catalyst comprises the following steps: uniformly mixing polyethylene with an aluminum oxide-loaded palladium catalyst, reacting at 150-180° C. for 3-8 hours, and separating the solid from the liquid to obtain diesel.

[0007] The palladium weight loading amount in the aluminum oxide-loaded transition metal catalyst is 0.01%-0.05%.

[0008] The particle size of the aluminum oxide-loaded transition metal catalyst is 2-4 mm.

[0009] The preparation method of the aluminum oxide-supported transition metal catalyst comprises the following steps: a. Add alumina to a mixed acid of hydrochloric acid and nitric acid, mix well, then treat at 40-50°C for 5-10 minutes, filter, wash, and dry to obtain modified alumina; b. Add the prepared modified alumina to a palladium nitrate solution and mix, then add sodium dodecylbenzene sulfonate, treat at 45-60°C for 0.5-3h, filter, and dry to obtain composite alumina; c. calcine the obtained composite alumina at 700-800°C for 1-8h under an inert atmosphere, and then cool down to obtain an aluminum oxide-supported palladium catalyst.

[0010] In step a, the mass fraction of hydrochloric acid is 10-20%, the mass fraction of nitric acid is 30-40%, and the volume ratio of hydrochloric acid to nitric acid is 1-3:1.

[0011] In step b, the mass ratio of modified aluminum oxide to palladium nitrate is 1:10-30.

[0012] The mass fraction of palladium nitrate solution in step b is 10-15%.

[0013] In step b, the mass of sodium dodecylbenzene sulfonate is 5-15% of the mass of modified alumina.

[0014] The present application includes at least one of the following beneficial technical effects: The method of the present invention uses aluminum oxide loaded transition metal catalyst as a catalyst to catalyze the degradation of polyethylene to prepare diesel. The corresponding catalyst is used, and there is no need to react under high pressure. The reaction temperature is also relatively mild, the implementation conditions are simple, energy is saved, and it can be widely promoted.

[0015] The diesel produced by the method of using aluminum oxide loaded transition metal catalyst as catalyst to catalyze the degradation of polyethylene to prepare diesel has a relatively concentrated molecular length range of components, fewer impurities and better oil quality. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is the gas chromatography-mass spectrometry test result of the product prepared by the present invention.

[0017] Figure 2 It is the mass spectrometry test result of each component of the product prepared by the present invention. DETAILED DESCRIPTION

[0018] The technical solution of the present application is further described below in conjunction with specific embodiments.

[0019] Example 1 The method for preparing diesel by catalyzing the degradation of polyethylene using an aluminum oxide-supported transition metal catalyst in this embodiment comprises the following steps: 1) Add 5 g of polyethylene into a 50 mL stainless steel reactor, then add 10 mg of alumina-supported palladium catalyst (Pd / Al2O3, palladium loading 0.05%, particle size 3.2 mm), and then seal the reactor.

[0020] 2) Turn on the stirring device and the heating device, heat to 160°C, react for 4 hours, then cool naturally to room temperature, open the reactor, filter, and obtain.

[0021] Example 2 The method for preparing diesel by catalyzing the degradation of polyethylene using an aluminum oxide-supported transition metal catalyst in this embodiment comprises the following steps: 1) Add 5 g of polyethylene into a 50 mL stainless steel reactor, then add 10 mg of alumina-supported palladium catalyst (Pd / Al2O3, palladium loading 0.05%, particle size 3.2 mm), and then seal the reactor.

[0022] 2) Turn on the stirring device and the heating device, heat to 150°C, react for 8 hours, then cool naturally to room temperature, open the reactor, filter, and obtain.

[0023] Example 3 The method for preparing diesel by catalyzing the degradation of polyethylene using an aluminum oxide-supported transition metal catalyst in this embodiment comprises the following steps: 1) Add 5 g of polyethylene into a 50 mL stainless steel reactor, then add 10 mg of alumina-supported palladium catalyst (Pd / Al2O3, palladium loading 0.05%, particle size 3.2 mm), and then seal the reactor.

[0024] 2) Turn on the stirring device and the heating device, heat to 180°C, react for 3 hours, then cool naturally to room temperature, open the reactor, filter, and obtain.

[0025] Example 4 The method for preparing diesel by catalyzing the degradation of polyethylene using an aluminum oxide-supported transition metal catalyst in this embodiment comprises the following steps: 1) Add 5g of polyethylene into a 50mL stainless steel reactor, then add 10mg of aluminum oxide-supported palladium catalyst, and then seal the reactor; The preparation method of the aluminum oxide supported palladium catalyst comprises the following steps: a. Add alumina to a mixed acid of hydrochloric acid and nitric acid, mix well, then heat to 40°C, stir for 10 minutes, filter, wash with deionized water, and dry to obtain modified alumina; the mixed acid is prepared by mixing hydrochloric acid and nitric acid in a volume ratio of 1:1, the mass fraction of hydrochloric acid is 15%, and the mass fraction of nitric acid is 33%; b. Add the prepared modified alumina to a 15% mass fraction of palladium nitrate solution and mix, the mass ratio of modified alumina to palladium nitrate is 1:25, then add sodium dodecylbenzene sulfonate with a mass of 30% of the mass of the modified alumina, and heat to 55°C under stirring, treat for 1h, filter, and dry the solid to obtain composite alumina; c. The obtained composite alumina was calcined at 750°C for 5 h under a nitrogen atmosphere, and then cooled to room temperature to obtain an aluminum oxide-supported palladium catalyst.

[0026] 2) Turn on the stirring device and the heating device, heat to 160°C, react for 4 hours, then cool naturally to room temperature, open the reactor, filter, and obtain.

[0027] Example 5 The method for preparing diesel by catalyzing the degradation of polyethylene using an aluminum oxide-supported transition metal catalyst in this embodiment comprises the following steps: 1) Add 5g of polyethylene into a 50mL stainless steel reactor, then add 10mg of aluminum oxide-supported palladium catalyst, and then seal the reactor; The preparation method of the aluminum oxide supported palladium catalyst comprises the following steps: a. Add alumina to a mixed acid of hydrochloric acid and nitric acid, mix well, then heat to 45°C, stir for 8 minutes, filter, wash with deionized water, and dry to obtain modified alumina; the mixed acid is prepared by mixing hydrochloric acid and nitric acid in a volume ratio of 1:1, the mass fraction of hydrochloric acid is 15%, and the mass fraction of nitric acid is 33%; b. Add the prepared modified alumina to a 15% mass fraction of palladium nitrate solution and mix, the mass ratio of modified alumina to palladium nitrate is 1:25, then add sodium dodecylbenzene sulfonate with a mass of 15% of the mass of the modified alumina, and heat to 55°C under stirring, treat for 1h, filter, and dry the solid to obtain composite alumina; c. The obtained composite alumina was calcined at 780°C for 5 h under a nitrogen atmosphere, and then cooled to room temperature to obtain an aluminum oxide-supported palladium catalyst.

[0028] 2) Turn on the stirring device and the heating device, heat to 160°C, react for 4 hours, then cool naturally to room temperature, open the reactor, filter, and obtain.

[0029] Experimental example The product obtained in Example 3 was tested on a gas chromatograph-mass spectrometer (GCMS). The test results are as follows: Figure 1 and Figure 2 shown.

[0030] Finally, it should be noted that the above is only a preferred embodiment of the present invention. For those skilled in the art, they can still modify the technical solutions recorded in the aforementioned embodiments, or replace some of the technical features therein with equivalents. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for preparing diesel by catalyzing the degradation of polyethylene using an aluminum oxide-supported transition metal catalyst, characterized in that: The method comprises the following steps: uniformly mixing polyethylene and aluminum oxide-supported palladium catalyst, reacting at 150-180° C. for 3-8 hours, and separating the solid from the liquid to obtain the product.

2. The method for preparing diesel by catalyzing the degradation of polyethylene using an aluminum oxide-supported transition metal catalyst as claimed in claim 1, characterized in that: The palladium weight loading amount in the aluminum oxide-loaded transition metal catalyst is 0.01%-0.05%.

3. The method for preparing diesel by catalyzing the degradation of polyethylene using an aluminum oxide-supported transition metal catalyst as claimed in claim 1, characterized in that: The particle size of the aluminum oxide-loaded transition metal catalyst is 2-4 mm.

4. The method for preparing diesel by catalyzing the degradation of polyethylene using an aluminum oxide-supported transition metal catalyst as claimed in any one of claims 1 to 3, characterized in that: The preparation method of the aluminum oxide-supported transition metal catalyst comprises the following steps: a. Add alumina to a mixed acid of hydrochloric acid and nitric acid, mix well, then treat at 40-50°C for 5-10 minutes, filter, wash, and dry to obtain modified alumina; b. Add the prepared modified alumina to a palladium nitrate solution and mix, then add sodium dodecylbenzene sulfonate, treat at 45-60°C for 0.5-3h, filter, and dry to obtain composite alumina; c. calcine the obtained composite alumina at 700-800°C for 1-8h under an inert atmosphere, and then cool down to obtain an aluminum oxide-supported palladium catalyst.

5. The method for preparing diesel by catalyzing the degradation of polyethylene using an aluminum oxide-supported transition metal catalyst as claimed in claim 4, characterized in that: In step a, the mass fraction of hydrochloric acid is 10-20%, the mass fraction of nitric acid is 30-40%, and the volume ratio of hydrochloric acid to nitric acid is 1-3:

1.

6. The method for preparing diesel by catalyzing the degradation of polyethylene using an aluminum oxide-supported transition metal catalyst as claimed in claim 4, characterized in that: In step b, the mass ratio of modified aluminum oxide to palladium nitrate is 1:10-30.

7. The method for preparing diesel by catalyzing the degradation of polyethylene using an aluminum oxide-supported transition metal catalyst as claimed in claim 4, characterized in that: The mass fraction of palladium nitrate solution in step b is 10-15%.

8. The method for preparing diesel by catalyzing the degradation of polyethylene using an aluminum oxide-supported transition metal catalyst as claimed in claim 4, characterized in that: In step b, the mass of sodium dodecylbenzene sulfonate is 5-15% of the mass of modified alumina.

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