Solid catalyst

Abstract

To provide a solid catalyst that has a high rate of conversion to decomposition products, has a high selectivity for oily products obtained as useful chemical raw materials, and is capable of producing decomposition products with suppressed isomerization, and a method for producing an oily product using the solid catalyst.SOLUTION: Provided are: (1) a solid catalyst in which ruthenium and one or more metals M selected from the group consisting of molybdenum, tungsten, manganese, iron, cobalt, nickel, copper, and zinc are co-supported on a carrier, the carrier being a metal oxide having a specific surface area of 10 to 1000 m2 / g; and (2) a method for producing an oily product, comprising the steps of: supplying a mixture obtained by contacting the solid catalyst described in (1) with plastic having a melting point or softening point of 250°C or less into a reaction system, supplying hydrogen into the reaction system, and pyrolyzing the plastic at 150°C or more to obtain an oily product.SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention relates to a solid catalyst and a method for producing an oily product by using the solid catalyst to obtain an oily product from plastics (particularly waste plastics). [Background technology]

[0002] Chemical recycling of waste plastics makes it possible to break down plastics containing different materials and impurities and convert them into a variety of useful chemical raw materials for use, and is expected to be a technology that will promote resource circulation and lead to resource conservation. As a method of chemically recycling such waste plastics, the development of a pyrolysis-to-oil process in which waste plastics are pyrolyzed to convert them into oil and reused as a raw material for useful chemicals is underway, and progress is being made in the development of catalysts suitable for converting waste plastics into oil.

[0003] For example, Patent Document 1 discloses a solid catalyst that is easy to recover and regenerate after the reaction is completed and can reduce the reaction temperature during the catalytic reaction, a method for producing the same, and a method for producing an oily product, which includes a carrier made of a metal oxide and ruthenium supported on the carrier, and has a specific surface area of ​​10 m 2 / g or more 1000m 2 The document describes a solid catalyst having a melting point of 250°C or less, and a method for producing an oily product comprising the steps of contacting the solid catalyst with a plastic having a melting point of 250°C or less and heat-treating the plastic in hydrogen at 100°C or more. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2020-185513 A Summary of the Invention [Problem to be solved by the invention]

[0005] In conventional pyrolysis to oil processes, the isomerization rate of the decomposition products is high. Therefore, it is desirable to develop a pyrolysis to oil process that can suppress the isomerization of the decomposition products. In addition, in order to convert waste plastics into useful chemical raw materials with high selectivity, a catalyst that can selectively break the chemical bonds of plastics is required. The technology of Patent Document 1 facilitates recovery and regeneration after the reaction and enables the reaction temperature during the catalytic reaction to be lowered, but it has been found that there is room for improvement in the conversion rate of plastics to decomposition products and the selectivity of oily substances obtained as useful chemical raw materials. An object of the present invention is to provide a solid catalyst which has a high conversion rate to decomposition products, has a high selectivity for oily products obtained as useful chemical raw materials, and is capable of obtaining decomposition products with suppressed isomerization, and a method for producing an oily product using the solid catalyst. [Means for solving the problem]

[0006] The present inventors have discovered that the above-mentioned problems can be solved by providing a solid catalyst in which ruthenium and one or more metals selected from the group consisting of molybdenum, tungsten, manganese, iron, cobalt, nickel, copper, and zinc are co-supported on a support, the support being a metal oxide having a specific surface area within a predetermined range. That is, the present invention provides the following [1] and [2]. [1] A solid catalyst in which ruthenium and one or more metals M selected from the group consisting of molybdenum, tungsten, manganese, iron, cobalt, nickel, copper, and zinc are co-supported on a carrier, The carrier has a specific surface area of ​​10 m 2 / g or more 1000m 2 / g or less of a metal oxide. [2] A method for producing an oily product, comprising the steps of: supplying a mixture obtained by contacting the solid catalyst described in [1] above with a plastic having a melting point or softening point of 250°C or lower into a reaction system; supplying hydrogen into the reaction system; and thermally decomposing the plastic at 150°C or higher to obtain an oily product. Effect of the Invention

[0007] According to the present invention, it is possible to provide a solid catalyst which has a high conversion rate to a decomposition product, has a high selectivity for an oily product obtained as a raw material for a useful chemical product, and is capable of obtaining a decomposition product with suppressed isomerization, and a method for producing an oily product using the solid catalyst. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] [Solid catalyst] The solid catalyst of the present invention is a solid catalyst in which ruthenium and one or more metals M selected from the group consisting of molybdenum, tungsten, manganese, iron, cobalt, nickel, copper, and zinc are co-supported on a carrier, and the carrier has a specific surface area of ​​10 m 2 / g or more 1000m 2 / g or less of metal oxides.

[0009] According to the present invention, it is possible to obtain a decomposition product with a high conversion rate to the decomposition product, a high selectivity for the oily material obtained as a useful chemical raw material, and suppressed isomerization. The reason for this is unclear, but is thought to be as follows. It is believed that the solid catalyst of the present invention can achieve both high conversion and selectivity due to the cooperative action of ruthenium supported on a metal oxide as a carrier and metal M. In addition, according to the present invention, hydrogen is added to the cleaved part of the plastic skeleton simultaneously with pyrolysis, so that isomerization of the decomposition product can be suppressed. For example, when polyethylene is pyrolyzed, it is believed that the production rate of linear decomposition products can be increased, and the selectivity of oily substances obtained as useful chemical raw materials can be further improved. This makes it easier to separate and recover useful chemical raw materials when refining the decomposition products.

[0010] <Supported metal> The supported metal of the present invention comprises ruthenium as a first supported metal and one or more metals M selected from the group consisting of molybdenum, tungsten, manganese, iron, cobalt, nickel, copper, and zinc as a second supported metal, from the viewpoints of improving the conversion rate to cracked products and the selectivity for oily substances, suppressing isomerization of the cracked products, and improving the production rate of linear cracked products.

[0011] The amount of ruthenium supported on the solid catalyst (i.e., out of the total mass of the solid catalyst, 100%) is preferably 0.01% by mass or more, more preferably 0.03% by mass or more, even more preferably 0.05% by mass or more, even more preferably 0.1% by mass or more, even more preferably 0.3% by mass or more, even more preferably 0.5% by mass or more, even more preferably 0.7% by mass or more, from the viewpoint of improving the activity of the solid catalyst and improving the conversion rate to cracked products, and from the viewpoint of improving the selectivity of oily products, suppressing the isomerization of cracked products, improving the production rate of linear cracked products, and reducing catalyst costs, it is preferably 10% by mass or less, more preferably 8% by mass or less, even more preferably 5% by mass or less, and even more preferably 3% by mass or less. In the solid catalyst of the present invention, the amount of ruthenium supported is calculated from the theoretical charge amount.

[0012] The metal M co-supported on the carrier together with ruthenium is, from the viewpoints of improving the conversion rate to cracked products and the selectivity for oily substances, of suppressing isomerization of the cracked products, and of improving the production rate of linear cracked products, preferably at least one metal selected from the group consisting of nickel and copper, and more preferably copper.

[0013] The amount of metal M supported on the solid catalyst (i.e., out of the total mass of the solid catalyst, 100%) is preferably 0.01% by mass or more, more preferably 0.03% by mass or more, even more preferably 0.05% by mass or more, still more preferably 0.1% by mass or more, still more preferably 0.2% by mass or more, still more preferably 0.3% by mass or more, still more preferably 0.4% by mass or more, still more preferably 0.5% by mass or more, from the viewpoint of improving the activity of the solid catalyst and improving the conversion rate to the cracked products, and is preferably 10% by mass or less, more preferably 8% by mass or less, and still more preferably 5% by mass or less. In the solid catalyst of the present invention, the amount of metal M supported is calculated from the theoretical charge amount.

[0014] The total amount of ruthenium and metal M supported on the solid catalyst (i.e., out of the total mass of the solid catalyst, 100%) is preferably 0.02% by mass or more, more preferably 0.06% by mass or more, even more preferably 0.1% by mass or more, still more preferably 0.2% by mass or more, still more preferably 0.4% by mass or more, still more preferably 0.8% by mass or more, and still more preferably 1% by mass or more, from the same viewpoint as above and from the viewpoint of reducing catalyst cost, it is preferably 20% by mass or less, more preferably 15% by mass or less, still more preferably 10% by mass or less, still more preferably 7% by mass or less, and still more preferably 5% by mass or less. In the solid catalyst of the present invention, the total amount of ruthenium and metal M supported is calculated from the theoretical charge amount.

[0015] The supported mass ratio [Ru / metal M] of the ruthenium and the metal M is preferably 0.01 or more, more preferably 0.10 or more, more preferably 0.20 or more, and even more preferably 0.25 or more, from the viewpoint of improving the conversion rate to cracked products and the selectivity of oily products, from the viewpoint of suppressing isomerization of cracked products, and from the viewpoint of improving the production rate of linear cracked products, and from the viewpoint of the same as above and from the viewpoint of reducing catalyst costs, it is preferably 15 or less, more preferably 12 or less, more preferably 10 or less, even more preferably 8.0 or less, even more preferably 6.0 or less, even more preferably 4.0 or less, even more preferably 3.0 or less, and even more preferably 2.0 or less. In the solid catalyst of the present invention, the supported mass ratio [Ru / metal M] is calculated from the theoretical charge amount.

[0016] <Carrier> The support according to the present invention has a specific surface area of ​​10 m2 or less, from the viewpoint of efficiently supporting metals, maintaining the strength of the solid catalyst, and exerting catalytic activity. 2 / g or more 1000m 2 / g or less of metal oxides. The metal oxide is, from the viewpoint of improving the conversion rate to decomposition products and the selectivity of oily substances, from the viewpoint of suppressing isomerization of the decomposition products, and from the viewpoint of improving the production rate of linear decomposition products, preferably at least one selected from the group consisting of cerium oxide (CeO2), zirconium oxide (ZrO2), a composite oxide of cerium oxide (CeO2) and zirconium oxide (ZrO2), γ-alumina (γ-Al2O3), titanium oxide (TiO2), magnesium oxide (MgO), silicon oxide (SiO2), and a crystalline aluminosilicate, more preferably at least one selected from the group consisting of cerium oxide (CeO2), zirconium oxide (ZrO2), and a composite oxide of cerium oxide (CeO2) and zirconium oxide (ZrO2), and even more preferably at least one selected from the group consisting of cerium oxide (CeO2) and zirconium oxide (ZrO2). The metal oxides may be used alone or in combination of two or more.

[0017] The specific surface area of ​​the metal oxide is preferably 15 m from the viewpoint of efficiently supporting the metal, maintaining the strength of the solid catalyst, and exerting catalytic activity. 2 / g or more, more preferably 20m 2 / g or more, more preferably 25m 2 / g or more, and from the same viewpoint as above, preferably 700m 2 / g or less, more preferably 500m 2 / g or less, more preferably 300m 2 / g or less, and even more preferably 200m 2 / g or less, and even more preferably 150m 2 / g or less, and even more preferably 110m 2 / g or less. The specific surface area of ​​the metal oxide is a BET specific surface area determined by the BET method, and is measured by the method described in the Examples.

[0018] (Preparation of solid catalyst) The solid catalyst of the present invention is preferably prepared by a method including a step of calcining a metal oxide in an air atmosphere, and then heat-treating a mixture of the calcined metal oxide with a ruthenium precursor and a metal M precursor in a nitrogen atmosphere.

[0019] As the metal oxide, the metal oxides exemplified above as the support are preferably used. The metal oxides may be used alone or in combination of two or more. The calcination temperature of the metal oxide is preferably 500°C or higher from the viewpoint of adjusting the specific surface area of ​​the metal oxide, improving the activity of the solid catalyst, and improving the conversion rate to cracked products, and is preferably 1500°C or lower, more preferably 1300°C or lower, and even more preferably 1000°C or lower from the viewpoint of improving the activity of the solid catalyst, improving the conversion rate to cracked products and the selectivity for oily substances, suppressing isomerization of the cracked products, and improving the production rate of linear cracked products. The time for calcining the metal oxide is preferably 0.5 hours or more, more preferably 1 hour or more, from the viewpoints of increasing the crystallinity of the metal oxide, improving the activity of the solid catalyst, and thereby improving the conversion rate to cracked products and the selectivity for oily substances, suppressing isomerization of the cracked products, and improving the production rate of linear cracked products, and is preferably 5 hours or less, more preferably 4 hours or less, from the viewpoint of efficiency in preparation of the solid catalyst. The method for calcining the metal oxide is not particularly limited, but examples thereof include a method of calcining in a calcination furnace and a method of calcining in a tubular flow device.

[0020] The method for supporting ruthenium and metal M on the calcined metal oxide is not particularly limited, but examples include a method in which the calcined metal oxide is impregnated with a ruthenium precursor solution and a precursor solution of metal M, the resulting mixture is heated and dried to obtain a mixture of the metal oxide, the ruthenium precursor, and the metal M precursor, and then the mixture of the metal oxide, the ruthenium precursor, and the metal M precursor is heat-treated under a nitrogen atmosphere. Examples of the method for impregnating the calcined metal oxide with a ruthenium precursor solution and a precursor solution of metal M include a method in which the calcined metal oxide is mixed with and impregnated with a ruthenium precursor solution and a precursor solution of metal M; and a method in which the calcined metal oxide is impregnated with either a ruthenium precursor solution or a precursor solution of metal M, and then impregnated with the other precursor solution. The ruthenium precursor solution was Ru(NO)(NO3). x (OH) 3-x Examples include: The content of ruthenium in the ruthenium precursor solution is preferably 0.3 mass% or more, more preferably 0.5 mass% or more, even more preferably 1 mass% or more, and preferably 5 mass% or less, more preferably 4 mass% or less, even more preferably 3 mass% or less. The precursor solution of metal M may be a solution of a nitrate of metal M. The content of metal M in the precursor solution of metal M is preferably 0.3 mass% or more, more preferably 0.5 mass% or more, even more preferably 1 mass% or more, and preferably 5 mass% or less, more preferably 4 mass% or less, even more preferably 3 mass% or less.

[0021] The atmosphere in which the mixture obtained by impregnating the metal oxide with the ruthenium precursor solution and the precursor solution of metal M is dried is not particularly limited, and the drying can be performed in an air atmosphere. The temperature for drying the mixture obtained by impregnating the metal oxide with the ruthenium precursor solution and the precursor solution of metal M is preferably 70°C or higher, more preferably 80°C or higher, and even more preferably 90°C or higher, from the viewpoint of improving the activity of the solid catalyst and improving the conversion rate to decomposition products, and the temperature is preferably 150°C or lower, more preferably 130°C or lower, and even more preferably 120°C or lower, from the viewpoint of improving the activity of the solid catalyst and improving the conversion rate to decomposition products and the selectivity for oily substances, suppressing isomerization of the decomposition products, and improving the production rate of linear decomposition products. The time for drying the mixture obtained by impregnating the metal oxide with the ruthenium precursor solution and the precursor solution of metal M is preferably 6 hours or more, more preferably 10 hours or more, from the viewpoints of sufficient catalyst formation, improving the activity of the solid catalyst, and improving the conversion rate to decomposition products and the selectivity for oily products, suppressing isomerization of the decomposition products, and improving the production rate of linear decomposition products, and is preferably 24 hours or less, more preferably 18 hours or less, from the viewpoint of efficiency in preparation of the solid catalyst.

[0022] The temperature for heat-treating the mixture of the metal oxide, the ruthenium precursor, and the metal M precursor is preferably 200°C or higher, more preferably 250°C or higher, and even more preferably 280°C or higher, from the viewpoint of improving the activity of the solid catalyst and improving the conversion rate to decomposition products, and the selectivity for oily products, from the viewpoint of suppressing isomerization of the decomposition products, and from the viewpoint of improving the production rate of linear decomposition products, the temperature is preferably 1000°C or lower, more preferably 800°C or lower, and even more preferably 500°C or lower. The time for heat treating the mixture of the metal oxide, the ruthenium precursor, and the metal M precursor is preferably 0.5 hours or more, more preferably 1 hour or more, from the viewpoints of sufficient catalyst formation, improving the activity of the solid catalyst, and thereby improving the conversion to decomposition products and the selectivity for oily products, suppressing isomerization of the decomposition products, and improving the production rate of linear decomposition products, and is preferably 3 hours or less, more preferably 2 hours or less, from the viewpoint of efficiency in preparation of the solid catalyst. The method for drying the mixture obtained by impregnating the metal oxide with a ruthenium precursor solution and a precursor solution of metal M, and the method for heat-treating the mixture of the metal oxide, the ruthenium precursor, and the metal M precursor are not particularly limited, and examples of the method include drying using a general air blower dryer or the like, and heat treatment using a calcination furnace or a tubular flow device.

[0023] [Method of producing oil] The method for producing an oily product of the present invention includes the steps of: supplying a mixture obtained by contacting the solid catalyst with a plastic having a melting point or softening point of 250°C or less into a reaction system; supplying hydrogen into the reaction system; and thermally decomposing the plastic to obtain an oily product.

[0024] In the production method of the present invention, the plastic to be subjected to thermal decomposition is not particularly limited as long as it has a melting point or softening point of 250° C. or less. Here, "plastics with a melting point or softening point of 250°C or lower" means plastics that are in a liquid state at 250°C. In the production method of the present invention, when the plastic to be subjected to thermal decomposition is waste plastic, the waste plastic may be crushed or foreign matter removed before being mixed with the solid catalyst. Examples of plastics include polyethylene (PE), polypropylene (PP), polystyrene (PS), polyvinyl chloride (PVC), polyethylene terephthalate (PET), polycarbonate (PC), polyamide (PA), poly(meth)acrylate resins, etc. Among these, from the viewpoint of converting waste plastics into useful chemical raw materials, preferred are resins obtained by polymerizing monomers having polymerizable double bonds contained in waste plastics. The resins obtained by polymerizing monomers having polymerizable double bonds are preferably at least one selected from the group consisting of polyolefin resins such as polyethylene (PE) and polypropylene (PP); polystyrene (PS); and polyvinyl chloride (PVC), and more preferably polyolefin resins.

[0025] The polyolefin resin is preferably one or more selected from the group consisting of polyethylene resins such as low density polyethylene (LDPE), linear low density polyethylene (LLDPE), and high density polyethylene (HDPE); polypropylene resins such as homopolypropylene, random polypropylene, and block polypropylene; and polyethylene / polypropylene copolymers. Among these, the polyolefin resin is more preferably polyethylene resin from the viewpoint of obtaining a highly useful chemical raw material.

[0026] The number average molecular weight (Mn) of the polyolefin resin is preferably 1,000 or more, more preferably 1,300 or more, and even more preferably 1,500 or more, and is preferably 30,000 or less, more preferably 20,000 or less, and even more preferably 10,000 or less. The number average molecular weight (Mn) of the polyolefin resin can be measured by gel permeation chromatography (GPC). The melt index (MI) of the polyolefin resin is preferably 0.1 g / 10 min or more, more preferably 0.5 g / 10 min or more, even more preferably 0.7 g / 10 min or more, and preferably 50 g / 10 min or less, more preferably 30 g / 10 min or less, even more preferably 20 g / 10 min or less. The melt index (MI) of a polyolefin resin can be determined by a measurement method in accordance with ASTM D 1238, and a value measured at a resin temperature of 190° C. and a load of 2.16 kg can be used.

[0027] In the manufacturing method of the present invention, the amount of solid catalyst used is, relative to 100 parts by mass of plastic, preferably 0.01 parts by mass or more, more preferably 0.1 parts by mass or more, even more preferably 0.5 parts by mass or more, still more preferably 1 part by mass or more, and still more preferably 2 parts by mass or more, from the viewpoints of exerting sufficient catalytic activity, improving the conversion rate to decomposition products and the selectivity to oily products, suppressing isomerization of the decomposition products, improving the production rate of linear decomposition products, and reducing catalyst costs, the amount is preferably 10 parts by mass or less, more preferably 7 parts by mass or less, even more preferably 5 parts by mass or less, and still more preferably 4 parts by mass or less.

[0028] In the production method of the present invention, the hydrogen pressure during the pyrolysis treatment is preferably 30 MPa or less, more preferably 20 MPa or less, even more preferably 10 MPa or less, still more preferably 6 MPa or less, and preferably 2 MPa or more, more preferably 3 MPa or more, even more preferably 4 MPa or more.

[0029] In the production method of the present invention, the reaction temperature during the thermal decomposition treatment is preferably 100°C or higher, more preferably 130°C or higher, even more preferably 150°C or higher, still more preferably 160°C or higher, still more preferably 180°C or higher, and still more preferably 200°C or higher, from the viewpoint of exerting sufficient catalytic activity and improving the conversion rate to decomposition products and the selectivity to oily products, from the viewpoint of suppressing isomerization of the decomposition products, and from the viewpoint of improving the production rate of linear decomposition products, and is preferably 250°C or lower from the viewpoint of reducing the energy load.

[0030] In the production method of the present invention, the reaction time during the thermal decomposition treatment is preferably 0.1 hours or more, more preferably 2 hours or more, even more preferably 3 hours or more, and even more preferably 6 hours or more, from the viewpoint of exerting sufficient catalytic activity and improving the conversion rate to decomposition products and the selectivity to oily products, from the viewpoint of suppressing isomerization of the decomposition products, and from the viewpoint of improving the production rate of linear decomposition products, and is preferably 100 hours or less, more preferably 72 hours or less, even more preferably 36 hours or less, and even more preferably 24 hours or less, from the viewpoint of reducing the energy load.

[0031] The conversion rate to decomposition products within 24 hours from the start of the thermal decomposition treatment is preferably 60 mol % or more, more preferably 70 mol % or more, even more preferably 80 mol % or more, and even more preferably 90 mol % or more. The conversion rate can be measured by the method described in the Examples.

[0032] According to the production method of the present invention, it is possible to suppress the generation of organic compounds having 1 to 4 carbon atoms as gas components, and to improve the selectivity of organic compounds having 5 to 45 carbon atoms as oily substances. As the oily substances, organic compounds having 8 to 45 carbon atoms are preferred. The organic compound having 8 to 45 carbon atoms can be obtained by distilling and refining the oily product, and can be used as a raw material for useful chemical products. For example, an organic compound having 8 to 20 carbon atoms is useful as a raw material for surfactants, an organic compound having 18 to 30 carbon atoms is useful as a wax used as an additive, and an organic compound having 15 to 45 carbon atoms is useful as a lubricant base oil. From the viewpoint of usefulness as a raw material for chemical products, these organic compounds obtained by the production method of the present invention are preferably hydrocarbon-based organic compounds.

[0033] In the present invention, the selectivity of gas components (organic compounds having 1 to 4 carbon atoms) in the total amount of decomposition products is preferably 10 mol % or less, more preferably 8 mol % or less, and even more preferably 6 mol % or less. In the present invention, the selectivity of organic compounds having 8 to 20 carbon atoms in the total amount of decomposition products is preferably 30 mol% or more, more preferably 35 mol% or more, even more preferably 40 mol% or more, and is preferably 80 mol% or less, more preferably 75 mol% or less, even more preferably 70 mol% or less. In the present invention, the selectivity of organic compounds having 18 to 30 carbon atoms in the total amount of decomposition products is preferably 20 mol% or more, more preferably 25 mol% or more, even more preferably 30 mol% or more, and preferably 65 mol% or less, more preferably 60 mol% or less, even more preferably 55 mol% or less. In the present invention, the selectivity of organic compounds having 15 to 45 carbon atoms in the total amount of decomposition products is preferably 30 mol% or more, more preferably 35 mol% or more, even more preferably 40 mol% or more, and preferably 85 mol% or less, more preferably 80 mol% or less, even more preferably 75 mol% or less. The selectivities of the gas components and various organic compounds are measured by the method described in the Examples.

[0034] According to the production method of the present invention, isomerization of decomposition products can be suppressed, and therefore, for example, when a polyolefin resin is thermally decomposed, an oily product having a high production rate of linear decomposition products can be obtained. In the present invention, the production rate of linear decomposition products in the total amount of decomposition products is preferably 60 mol% or more, more preferably 65 mol% or more, even more preferably 70 mol% or more, still more preferably 75 mol% or more, and even more preferably 80 mol% or more, and from the viewpoint of ease of production, it is 100 mol% or less, preferably 99 mol% or less, and more preferably 97 mol% or less. The production rate of linear decomposition products can be determined by the method described in the Examples. EXAMPLES

[0035] The measurements were carried out by the following method. [Specific surface area of ​​metal oxide] The specific surface area of ​​the metal oxide was measured by the BET method using a fully automatic specific surface area measuring device "Gemini VII 2360" (manufactured by Shimadzu Corporation).

[0036] (Preparation of solid catalyst) Preparation Example 1 Zirconium oxide (ZrO2) powder "RC-100" (manufactured by Daiichi Kigenso Kagaku Kogyo Co., Ltd.) was calcined at 600°C for 3 hours in an air atmosphere. The specific surface area of ​​the calcined zirconium oxide was 46.9 m 2 / g. 0.940 g of calcined zirconium oxide as a support was mixed with and impregnated into 1.333 g of a ruthenium nitrosyl nitrate aqueous solution (ruthenium content: 1.5% by mass) as a ruthenium (Ru) precursor solution and 2.667 g of a copper nitrate aqueous solution (copper content: 1.5% by mass) as a copper (Cu) precursor solution, and the resulting mixture was dried at 110°C in an air atmosphere for 12 hours and then heat-treated at 300°C for 1 hour in a nitrogen atmosphere to obtain a solid catalyst (Ru-Cu / ZrO2) (hereinafter referred to as "solid catalyst 1") having a ruthenium loading of 2% by mass and a copper loading of 4% by mass.

[0037] Preparation Example 2 A solid catalyst (Ru-Cu / ZrO) having a ruthenium loading of 1 mass% and a copper loading of 4 mass% (hereinafter referred to as "solid catalyst 2") was obtained in the same manner as in Preparation Example 1, except that the amount of calcined zirconium oxide (ZrO) powder, the ruthenium precursor solution, and the copper precursor solution were changed to 0.950 g, 0.667 g, and 2.667 g, respectively.

[0038] Preparation Example 3 A solid catalyst (Ru-Cu / ZrO) having a ruthenium loading of 1 mass % and a copper loading of 0.5 mass % (hereinafter referred to as "solid catalyst 3") was obtained in the same manner as in Preparation Example 1, except that the amount of calcined zirconium oxide (ZrO) powder, the amount of ruthenium precursor solution, and the amount of copper precursor solution were changed to 0.985 g, 0.667 g, and 0.333 g, respectively.

[0039] Preparation Example 4 Cerium oxide (CeO2) powder "Type-A" (manufactured by Daiichi Kigenso Kagaku Kogyo Co., Ltd.) was calcined at 600°C for 3 hours in an air atmosphere. The specific surface area of ​​the calcined cerium oxide was 102.8 m 2 / g. 0.950 g of calcined cerium oxide as a support was mixed with and impregnated into 1.667 g of a ruthenium nitrosyl nitrate aqueous solution (ruthenium content: 1.5%) as a ruthenium (Ru) precursor solution and 1.667 g of a copper nitrate aqueous solution (copper content: 1.5%) as a copper (Cu) precursor solution, and the resulting mixture was dried at 110°C in an air atmosphere for 12 hours and then heat-treated at 300°C for 1 hour in a nitrogen atmosphere to obtain a solid catalyst (Ru-Cu / CeO2) (hereinafter referred to as "solid catalyst 4") having a ruthenium loading of 2.5 mass% and a copper loading of 2.5 mass%.

[0040] Preparation Example 5 Zirconium oxide (ZrO2) powder "RC-100" (manufactured by Daiichi Kigenso Kagaku Kogyo Co., Ltd.) was calcined at 600°C for 3 hours in an air atmosphere. The specific surface area of ​​the calcined zirconium oxide was 46.9 m 2 / g. 0.950 g of calcined zirconium oxide as a support was mixed with and impregnated into 1.667 g of a ruthenium nitrosyl nitrate aqueous solution (ruthenium content: 1.5% by mass) as a ruthenium (Ru) precursor solution and 1.667 g of a nickel nitrate aqueous solution (nickel content: 1.5% by mass) as a nickel (Ni) precursor solution, and the resulting mixture was dried at 110°C in an air atmosphere for 12 hours and then heat-treated at 300°C for 1 hour in a nitrogen atmosphere, thereby obtaining a solid catalyst (Ru-Ni / ZrO2) (hereinafter referred to as "solid catalyst 5") having a ruthenium loading amount of 2.5% by mass and a nickel loading amount of 2.5% by mass.

[0041] Preparation Example 6 Zirconium oxide (ZrO2) powder "RC-100" (manufactured by Daiichi Kigenso Kagaku Kogyo Co., Ltd.) was calcined at 700°C for 3 hours in an air atmosphere. The specific surface area of ​​the calcined zirconium oxide was 31.7 m 2 / g. A solid catalyst (Ru-Cu / ZrO2) (hereinafter referred to as "solid catalyst 6") having a ruthenium loading of 1 mass% and a copper loading of 4 mass% was obtained in the same manner as in Preparation Example 2, except that the support was changed to calcined zirconium oxide.

[0042] Preparation Example 7 Cerium oxide (CeO2) powder "Type-A" (manufactured by Daiichi Kigenso Kagaku Kogyo Co., Ltd.) was calcined at 800°C for 3 hours in an air atmosphere. The specific surface area of ​​the calcined cerium oxide was 48.7m 2 / g. A solid catalyst (Ru-Cu / CeO2) (hereinafter referred to as "solid catalyst 7") having a ruthenium loading of 1 mass% and a copper loading of 4 mass% was obtained in the same manner as in Preparation Example 2, except that the support was changed to calcined cerium oxide.

[0043] Preparation Example 8 Cerium oxide (CeO2) powder "Type-A" (manufactured by Daiichi Kigenso Kagaku Kogyo Co., Ltd.) was calcined at 900°C for 3 hours in an air atmosphere. The specific surface area of ​​the calcined cerium oxide was 30.2 m 2 / g. A solid catalyst (Ru-Cu / CeO2) (hereinafter referred to as "solid catalyst 8") having a ruthenium loading of 1 mass% and a copper loading of 4 mass% was obtained in the same manner as in Preparation Example 2, except that the support was changed to calcined cerium oxide.

[0044] Preparation Example 9 A solid catalyst (Ru-Cu / ZrO) having a ruthenium loading of 0.5 mass% and a copper loading of 0.05 mass% (hereinafter referred to as "solid catalyst 9") was obtained in the same manner as in Preparation Example 1, except that the amount of calcined zirconium oxide (ZrO) powder, the ruthenium precursor solution, and the copper precursor solution were changed to 0.9945 g, 0.3333 g, and 0.0333 g, respectively.

[0045] Comparative Preparation Example 1 Zirconium oxide (ZrO2) powder "RC-100" (manufactured by Daiichi Kigenso Kagaku Kogyo Co., Ltd.) was calcined at 600 °C for 3 hours in an air atmosphere, and the calcined zirconium oxide was used as a solid catalyst (ZrO2) (hereinafter referred to as "solid catalyst C1"). The specific surface area of ​​the calcined zirconium oxide was 46.9 m 2 / g.

[0046] Comparative Preparation Example 2 Zirconium oxide (ZrO2) powder "RC-100" (manufactured by Daiichi Kigenso Kagaku Kogyo Co., Ltd.) was calcined at 600°C for 3 hours in an air atmosphere. The specific surface area of ​​the calcined zirconium oxide was 46.9 m 2 / g. 0.960 g of calcined zirconium oxide as a support was mixed with and impregnated with 2.667 g of an aqueous solution of copper nitrate (copper content: 1.5% by mass) as a copper (Cu) precursor solution. The resulting mixture was dried at 110°C in an air atmosphere for 12 hours and then heat-treated at 300°C for 1 hour in a nitrogen atmosphere to obtain a solid catalyst (Cu / ZrO2) with a copper loading of 4% by mass (hereinafter referred to as "solid catalyst C2").

[0047] Comparative Preparation Example 3 Zirconium oxide (ZrO2) powder "RC-100" (manufactured by Daiichi Kigenso Kagaku Kogyo Co., Ltd.) was calcined at 600°C for 3 hours in an air atmosphere. The specific surface area of ​​the calcined zirconium oxide was 46.9 m 2 / g. 0.990 g of calcined zirconium oxide as a support was mixed with and impregnated with 0.667 g of an aqueous solution of ruthenium nitrosyl nitrate (ruthenium content: 1.5% by mass) as a ruthenium (Ru) precursor solution, and the resulting mixture was dried at 110°C in an air atmosphere for 12 hours and then heat-treated at 300°C for 1 hour in a nitrogen atmosphere to obtain a solid catalyst (Ru / ZrO2) with a ruthenium loading of 1% by mass (hereinafter referred to as "solid catalyst C3").

[0048] Comparative Preparation Example 4 Zirconium oxide (ZrO2) powder "RC-100" (manufactured by Daiichi Kigenso Kagaku Kogyo Co., Ltd.) was calcined at 600°C for 3 hours in an air atmosphere. The specific surface area of ​​the calcined zirconium oxide was 46.9 m 2 / g. 0.960 g of calcined zirconium oxide as a support was mixed with and impregnated with 2.667 g of an aqueous nickel nitrate solution (nickel content: 1.5% by mass) as a nickel (Ni) precursor solution. The resulting mixture was dried at 110°C in an air atmosphere for 12 hours and then heat-treated at 300°C for 1 hour in a nitrogen atmosphere to obtain a solid catalyst (Ni / ZrO2) with a nickel loading of 4% by mass (hereinafter referred to as "solid catalyst C4").

[0049] Comparative Preparation Example 5 Cerium oxide (CeO2) powder "Type-A" (manufactured by Daiichi Kigenso Kagaku Kogyo Co., Ltd.) was calcined at 600°C for 3 hours in an air atmosphere. The specific surface area of ​​the calcined cerium oxide was 102.8 m 2 / g. 0.960 g of calcined cerium oxide as a support was mixed with and impregnated with 2.667 g of an aqueous solution of copper nitrate (copper content: 1.5% by mass) as a copper (Cu) precursor solution. The resulting mixture was dried at 110°C in an air atmosphere for 12 hours and then heat-treated at 300°C for 1 hour in a nitrogen atmosphere to obtain a solid catalyst (Cu / CeO2) with a copper loading of 4% by mass (hereinafter referred to as "solid catalyst C5").

[0050] Comparative Preparation Example 6 Cerium oxide (CeO2) powder "Type-A" (manufactured by Daiichi Kigenso Kagaku Kogyo Co., Ltd.) was calcined at 600°C for 3 hours in an air atmosphere. The calcined cerium oxide was used as a solid catalyst (CeO2) (hereinafter referred to as "solid catalyst C6"). The specific surface area of ​​the calcined cerium oxide was 102.8 m 2 / g.

[0051] Comparative Preparation Example 7 Cerium oxide (CeO2) powder "Type-A" (manufactured by Daiichi Kigenso Kagaku Kogyo Co., Ltd.) was calcined at 600°C for 3 hours in an air atmosphere. The specific surface area of ​​the calcined cerium oxide was 102.8 m 2 / g. 0.950 g of calcined cerium oxide as a support was mixed with and impregnated with 3.333 g of an aqueous solution of ruthenium nitrosyl nitrate (ruthenium content: 1.5% by mass) as a ruthenium (Ru) precursor solution, and the resulting mixture was dried at 110°C in an air atmosphere for 12 hours and then heat-treated at 300°C for 1 hour in a nitrogen atmosphere to obtain a solid catalyst (Ru / CeO2) with a ruthenium loading of 5% by mass (hereinafter referred to as "solid catalyst C7").

[0052] [Table 1]

[0053] Example 1 100 mg of the solid catalyst 1 obtained in Preparation Example 1, 3.4 g of low-density polyethylene (Sigma-Aldrich, number average molecular weight Mn: 1,700) (hereinafter referred to as "LDPE"), and a glass stirrer tip were placed in an autoclave equipped with stirring and temperature control functions. Next, the atmosphere inside the autoclave was replaced with hydrogen three times, and then hydrogen was introduced into the autoclave so that the internal pressure of the autoclave became 3 MPa, and the autoclave was sealed. Next, the temperature inside the autoclave was raised to 240° C. over 1 hour, and then the reaction was carried out for 8 hours while the temperature inside the autoclave was maintained at 240° C. and the solid catalyst and low-density polyethylene were stirred by rotating the glass stirrer tip at a rotation speed of 450 rpm. The pressure inside the autoclave at the start of the reaction was 5 MPa. Thereafter, the temperature inside the autoclave was rapidly cooled to room temperature with ice water. After cooling, the entire gas component (gas phase) was removed from the autoclave and placed in a gas bag. Then, 40 μL of dichloromethane was introduced as an internal standard into the gas bag containing the gas. In addition, 100 mg of 9,10-dihydroanthracene and mesitylene were added as internal standards to the autoclave after cooling, and an oily substance (liquid phase) was collected. The collected gas components (gas phase) and oily matter (liquid phase) were analyzed using a gas chromatograph / flame ionization detector (GC-FID) "GC-2014" (Shimadzu Corporation). After cooling, the solid was collected from the autoclave by vacuum filtration, and the mass of the solid was measured. The mass obtained by subtracting the mass of the introduced solid catalyst was used to calculate the conversion rate (reaction rate) according to the following formula (1). In addition, from the results of the analysis by gas chromatography, the selectivity of each decomposition product in the total amount of decomposition products was calculated from the total amount of decomposition products, including the total amount of decomposition products, gas components (hereinafter referred to as "C1-C4"), organic compounds having 8 to 20 carbon atoms (hereinafter referred to as "C8-C20"), organic compounds having 18 to 30 carbon atoms (hereinafter referred to as "C18-C30"), and organic compounds having 15 to 45 carbon atoms (hereinafter referred to as "C15-C45"), according to the following formula (2). Furthermore, from the results of the analysis by gas chromatography, the production rate of normal bodies (straight-chain decomposition products) was calculated according to the following formula (3). The results are shown in Table 2. Conversion rate (mol%-C) = [[introduced substrate amount (mol-C) - recovered solid amount (mol-C)] / introduced substrate amount (mol-C)] × 100 (1) Here, the "introduced substrate" in formula (1) means a plastic that is decomposed using a solid catalyst. For example, in Example 1, it is low-density polyethylene. Selectivity (mol%-C) = [amount of each decomposition product (mol-C) / total amount of decomposition products (mol-C)] × 100 (2) Linear decomposition product formation rate (mol%-C) = [Linear decomposition product formation amount (mol-C) / Total amount of decomposition products (mol-C)] × 100 (3)

[0054] Examples 2 to 15, Comparative Examples 1 to 7 The reaction was carried out in the same manner as in Example 1, except that the solid catalyst and resin used, and the thermal decomposition treatment conditions were changed as shown in Table 2. After the reaction was completed, the gas components and oily matter were analyzed, and the conversion rate, the selectivity of various decomposition products, and the production rate of linear decomposition products were calculated from the above formulas (1) to (3). The results are shown in Table 2. The resins subjected to the pyrolysis treatment in Examples 7 and 8 were linear low-density polyethylene (LLDPE) (Sigma-Aldrich Corp., melt index (MI) at 190°C, 2.16 kg: 1 g / 10 min) and high-density polyethylene (HDPE) (Sigma-Aldrich Corp., melt index (MI) at 190°C, 2.16 kg: 12 g / 10 min), respectively. In Example 6 and Comparative Example 4, when the solid catalysts 5 and C4 were used for the thermal decomposition of resins, they were subjected to a preliminary reduction treatment at 700° C. for 1 hour under a hydrogen gas flow rate of 30 mL / min, cooled to room temperature under a hydrogen gas flow rate, and then subjected to a stabilization treatment for 30 minutes under a 2% oxygen / nitrogen mixed gas flow rate of 30 mL / min.

[0055] [Table 2]

[0056] From Table 2, it can be seen that, compared with Comparative Examples 1 to 7, Examples 1 to 15 have a higher conversion rate to cracked products, a lower selectivity for gas components, and therefore a higher selectivity for oily substances, and a higher selectivity for organic compounds having 8 to 20 carbon atoms used as surfactant raw materials, organic compounds having 18 to 30 carbon atoms used in wax as an additive, and organic compounds having 15 to 45 carbon atoms used in lubricant base oils. In addition, it can be seen that, since Examples 1 to 15 have a higher production rate of linear cracked products, isomerization of the cracked products is suppressed. [Industrial Applicability]

[0057] According to the present invention, the conversion rate to decomposition products is high, the selectivity of oily substances that can be used as raw materials for useful chemical products is high, and isomerization of the decomposition products can be suppressed. Therefore, for example, when polyethylene resin is used as waste plastic, the production rate of linear decomposition products can be improved. It is possible to provide a solid catalyst useful in the thermal decomposition to oil of waste plastics having a melting point or softening point of 250°C or less, and a method for producing oily substances using the solid catalyst.

Claims

1. a solid catalyst in which ruthenium and one or more metals M selected from the group consisting of molybdenum, tungsten, manganese, iron, cobalt, nickel, copper, and zinc are co-supported on a carrier; The carrier has a specific surface area of ​​10 m 2 / g or more 1000m 2 / g or less of a metal oxide.

2. 2. The solid catalyst according to claim 1, wherein the metal oxide is at least one selected from the group consisting of cerium oxide, zirconium oxide, a composite oxide of cerium oxide and zirconium oxide, γ-alumina, titanium oxide, magnesium oxide, silicon oxide, and crystalline aluminosilicates.

3. 2. The solid catalyst according to claim 1, wherein the mass ratio of the ruthenium to the metal M [Ru / metal M] is 0.01 or more and 15 or less.

4. 1. A method for producing an oily substance, comprising the steps of: supplying a mixture obtained by contacting the solid catalyst according to claim 1 with a plastic having a melting point or softening point of 250°C or lower into a reaction system; supplying hydrogen into the reaction system; and thermally decomposing the plastic at 150°C or higher to obtain an oily substance.

5. 5. The method for producing an oily substance according to claim 4, wherein the plastic is a resin obtained by polymerizing a monomer having a polymerizable double bond.

6. The method for producing an oily substance according to claim 5, wherein the resin obtained by polymerizing a monomer having a polymerizable double bond is a polyolefin resin.

7. The method for producing an oily substance according to any one of claims 4 to 6, wherein the oily substance is an organic compound having from 8 to 45 carbon atoms.