Copper-based composite catalyst and method for selecting its oxidation state

Abstract

The present invention relates to a copper-based composite catalyst and a method for selecting the same, characterized in that it has a specific content of copper on its surface and has a specific ratio depending on the oxidation state of copper. The copper-based composite catalyst according to the present invention has almost no change in strength and exhibits excellent reactivity when used in the production of neopentyl glycol (NPG).

Description

Technical Field

[0001] The present invention relates to a copper-based composite catalyst and a method for selecting its oxidation number. This application claims the benefit of the filing date of Korean Patent Application No. 10-2024-0009953, filed with the Korean Intellectual Property Office on January 23, 2024, and all of its contents are incorporated herein by reference.

Background Art

[0002] Neopentyl glycol (NPG) is a white crystalline substance with a melting point of 130 °C or higher, used as an important intermediate for various synthetic resins, and industrially widely used as a raw material for various plastic powder coatings, synthetic lubricants, plasticizers, surfactants, fiber processing agents, etc.

[0003] Such NPG is usually produced by subjecting isobutyraldehyde and formaldehyde to an aldol condensation reaction to produce hydroxypivaldehyde (HPA), and then reacting the HPA with hydrogen under a catalyst. At this time, for high yields, it is carried out under conditions of high temperature (160 °C or higher) and high pressure (35 bar or higher) in the presence of a copper-based composite catalyst.

[0004] However, when using a copper-based composite catalyst, since the reaction is carried out under high temperature and high pressure conditions, the strength of the catalyst is an important factor, and therefore, in the art, a copper-based composite catalyst containing copper oxide (CuO) is used.

[0005] Since the copper-based composite catalyst exhibits a large difference in reaction activity depending on the oxidation number of copper, in order to control the activity of the catalyst, it is important to determine not only the content of copper constituting the catalyst but also the component ratio according to the oxidation number with respect to copper. At this time, in order to adjust the component ratio of copper having a specific oxidation number and confirm the feasibility of manufacturing a catalyst having desired physical properties, it is important to accurately measure the ratio according to the oxidation number of copper in the copper-based composite catalyst.

[0006] Therefore, in order to improve catalytic properties such as catalyst stability and activity, technological development is continuously underway to develop methods for accurately measuring and determining the component ratio of copper with a specific oxidation state. [Overview of the project] [Problems that the invention aims to solve]

[0007] This specification aims to provide copper-based composite catalysts and methods for selecting their oxidation states. [Means for solving the problem]

[0008] One embodiment of this specification provides a copper-based composite catalyst comprising a surface containing 2.5 at% to 7.5 at% copper, wherein the copper comprises 10% to 50% copper with oxidation state 0, 1 copper, and 50% to 90% copper with oxidation state 2, and the content and ratios are obtained by the method 1 described below.

[0009] [Method 1] An XPS spectrum was obtained for the surface of a copper-based composite catalyst, including a main peak for copper with oxidation state 0, a main peak for copper with oxidation state 1, a main peak for copper with oxidation state 2, and a satellite peak for copper. The area of ​​the XPS spectrum is used to obtain the total copper content (at%) and the ratio (%) of copper with oxidation states 0 and 1, and copper with oxidation state 2, respectively.

[0010] Another embodiment of this specification provides an oxidation state sorting method for a copper-based composite catalyst, comprising the steps of: obtaining an XPS spectrum of the surface of a copper-based composite catalyst including a main peak for copper with oxidation state 0, a main peak for copper with oxidation state 1, and a main peak for copper with oxidation state 2, and a satellite peak for copper; and using the area of ​​the XPS spectrum to calculate the total copper content (at%) and the ratios (%) of copper with oxidation states 0 and 1, and copper with oxidation state 2, respectively. [Effects of the Invention]

[0011] The copper-based composite catalyst according to the present invention has high strength, shows almost no change in strength before and after post-treatment, exhibits almost no copper leaching during storage, processing, or use, and has a very fast hydrogen consumption reaction rate and excellent reactivity when used in the production of neopentyl glycol (NPG). The oxidation state selection method for copper-based composite catalysts according to the present invention can accurately measure the content of a specific oxidation state within the copper-based composite catalyst, and can also calculate trace amounts of oxidation state content. [Brief explanation of the drawing]

[0012] [Figure 1] This figure shows the XPS spectrum of a copper-based composite catalyst (Example 1-1) produced by the selection method according to the embodiments of this specification. [Figure 2] This figure shows the XPS spectra of copper-based composite catalysts (Examples 1-2) produced by the selection method according to the embodiments of this specification. [Figure 3] This figure shows the XPS spectra of copper-based composite catalysts (Examples 1-3) produced by the selection method according to the embodiments of this specification. [Figure 4] This figure shows the XPS spectrum of a copper-based composite catalyst (Comparative Example 1-1) in comparison to the embodiments described herein. [Figure 5] This figure shows the XPS spectra of copper-based composite catalysts (Comparative Examples 1-2) in comparison with the embodiments described herein. [Figure 6] This figure shows the XPS spectrum of a copper-based composite catalyst (Comparative Example 2-2 (Figure 6)) compared with the embodiments described herein. [Figure 7] This figure shows the XPS spectrum of a copper-based composite catalyst (Comparative Example 2-3 (Figure 7)) compared with the embodiments described herein. [Figure 8] This figure shows the XPS spectrum of a copper-based composite catalyst according to an embodiment of this specification (Example 2-3 (Figure 8)). [Figure 9] This figure shows the XPS spectrum of a copper-based composite catalyst (Comparative Example 2-4 (Figure 9)) compared with the embodiments described herein.

Best Mode for Carrying Out the Invention

[0013] Hereinafter, the present invention will be described in detail so that those having ordinary knowledge in the technical field to which the present invention pertains can easily implement it. However, the present invention can be implemented in various different forms and is not limited to only the configurations described herein.

[0014] In this specification, when a certain part "includes" a certain component, this means that, unless otherwise stated to the contrary, it does not exclude other components and may further include other components. In this specification, "p~q" means "p or more and q or less".

[0015] In this specification, Cu(0) represents copper with an oxidation number of 0, Cu(I) represents copper with an oxidation number of 1, and Cu(II) represents copper with an oxidation number of 2.

[0016] In this specification, the Cu 2p on the XPS spectrum 3 / 2 [[ID=Z23]]The main peak means that within the 2p spectrum of Cu, the intensity rapidly increases within the range of the binding energy (B.E.) of 928.0 eV to 939.0 eV (a high peak shape), and the satellite peak means that the intensity gradually increases within the range of the binding energy (B.E.) of 939.0 eV to 950.0 eV (a low mound form) (see FIGS. 1 to 9).

[0017] In this specification, the main peak for copper with an oxidation number of 0, the main peak for copper with an oxidation number of 1, and the main peak for copper with an oxidation number of 2 can be expressed as the Cu(0) main peak, the Cu(I) main peak, and the Cu(II) main peak, respectively.

[0018] In this specification, "strength" refers to the peeling strength of the catalyst, and specifically, it may mean the strength calculated from the average of 20 maximum peeling strengths at the initial decay point using SHIMPO's FGN-50B. Furthermore, in explaining the present invention, detailed explanations of such prior art, which may unnecessarily obscure the gist of the present invention, will be omitted.

[0019] <Copper-based composite catalyst> One embodiment of this specification provides a copper-based composite catalyst containing 2.5 at% to 7.5 at% of copper relative to the surface, wherein the copper comprises 10% to 50% copper with oxidation state 0, 1 copper, and 50% to 90% copper with oxidation state 2, and the content and ratios are obtained by the method 1 described below.

[0020] [Method 1] An XPS spectrum was obtained for the surface of a copper-based composite catalyst, including a main peak for copper with oxidation state 0, a main peak for copper with oxidation state 1, and a main peak for copper with oxidation state 2 and a satellite peak for copper. The area of ​​the aforementioned XPS spectrum is used to obtain the total copper content (at%) and the ratio (%) of copper with oxidation states 0 and 1, and copper with oxidation state 2, respectively. Copper-based composite catalysts satisfying the aforementioned content (at%) and ratio (%) exhibit high strength, minimal change in strength before and after post-treatment, improved stability, and, when used in the production of neopentyl glycol (NPG), exhibit a very fast hydrogen consumption reaction rate and excellent reactivity.

[0021] In this specification, the content (at%) may be expressed in terms of atomic concentration. In this specification, the main and satellite peaks for each oxidation state are calculated as the area of ​​the XPS spectrum, and the oxidation state is selected and / or quantified using the area for each peak by the method specifically described herein. In one embodiment of this specification, the ratio (%) of copper with oxidation states of 0 and 1 can be calculated by the following formula 1, and the ratio (%) of copper with oxidation state of 2 can be calculated by the following formula 2.

[0022]

number

number

[0023] In the above formulas 1 and 2, Cu(0), Cu(I), and Cu(II) represent copper with an oxidation state of 0, copper with an oxidation state of 1, and copper with an oxidation state of 2, respectively.

number

[0024] In this specification, the ratio of copper in the copper-based composite catalyst by oxidation state is the value obtained by formulas 1 and 2, respectively. Specifically, the ratio (%) of copper with oxidation states of 0 and 1 is calculated using formula 1, and the ratio (%) of copper with oxidation state of 2 is calculated using formula 2.

[0025] A copper-based composite catalyst according to one embodiment of this specification may be further treated by methods known in the art, without departing from the scope of the present invention. Examples of such additional treatments include hydrothermal treatment.

[0026] In this specification, hydrothermal treatment is one of the post-treatments for controlling the strength of the catalyst, and the hydrothermal treatment method is a method known in the industry and is not particularly limited as long as it does not deviate from the present invention.

[0027] In one embodiment of this specification, the surface may mean a region with a depth of 0 nm to 10 nm in the central direction at the interface of the copper-based composite catalyst in contact with the atmosphere.

[0028] In one embodiment of this specification, the area of ​​the XPS spectrum may represent the total area (first area value) of the main peak for copper with oxidation state 0 and the main peak for copper with oxidation state 1, the total area (second area value) of the main peak for copper with oxidation state 2, and the total area (third area value) of the satellite peaks for copper.

[0029] In one embodiment of this specification, the first to third area values ​​can be measured by setting the background using the Shirley method and performing a fitting process using the Lorentzian / Gaussian (L / G) function and FWHM (Full Width Half Maximum).

[0030] In one embodiment of this specification, the copper-based composite catalyst may comprise at least one of a copper oxide and a copper structure.

[0031] In this specification, copper oxides may be represented as Cu-O, and copper structures are [ka] (n has no upper limit as long as it corresponds to an integer greater than or equal to 1, and can be expressed as A = Al, Si, or other elements.)

[0032] In this specification, copper oxides and copper structures refer to catalyst structures containing copper that have catalytic activity and play a primary role in catalytic reactions.

[0033] In one embodiment of this specification, the copper-based composite catalyst may further include a support.

[0034] In this specification, the carrier is a substance that disperses and holds the copper oxide and structure on its surface. Typical examples include silica and alumina, but zeolite, titania, magnesia, zirconia, carbon, diatomaceous earth, etc., can also be used as a carrier. It is not particularly limited as long as it does not deviate from the present invention as is known in the industry.

[0035] A copper-based composite catalyst according to one embodiment of this specification may be a catalyst for the production of neopentyl glycol. When the copper-based composite catalyst is used in the production of neopentyl glycol, reactivity such as reaction efficiency is improved, strength is improved, and there is no change in strength, and the stability of the catalyst structure itself is improved.

[0036] <Method for selecting copper-based composite catalysts by oxidation state> One embodiment of this specification provides a method for selecting the oxidation state of copper-based composite catalysts using X-ray photoelectron spectroscopy (XPS).

[0037] More specifically, the method for selecting the oxidation state of copper-based composite catalysts according to this specification is characterized by calculating the total copper content (at%) and the ratio of copper by oxidation state using the area of ​​the XPS spectrum of the copper-based composite catalyst, which includes a main peak for copper with oxidation state 0, a main peak for copper with oxidation state 1, and a main peak for copper with oxidation state 2 and a satellite peak for copper. The method for selecting the oxidation state of a copper-based composite catalyst according to one embodiment of this specification is applicable as long as the copper-based composite catalyst contains 0.1 at% or more copper on its surface. The oxidation state selection method for copper-based composite catalysts according to the present invention can be applied within the aforementioned range.

[0038] If the total content of copper with oxidation state 0 and copper with oxidation state 1 is less than 0.05 at% due to the detection limit of XPS, the oxidation state selection method for copper-based composite catalysts according to the present invention cannot be applied. Furthermore, if the total content of copper with oxidation state 0 and copper with oxidation state 1 is 100 at%, it relates to copper metal or Cu2O, and there is no reason to select the oxidation state content of copper.

[0039] A copper-based composite catalyst according to one embodiment of this specification may be provided using techniques commonly used in the art, except that the content of copper [Cu(0)] with an oxidation state of 0, copper [Cu(I)] with an oxidation state of 1, and copper [Cu(II)] with an oxidation state of 2, as measured by an oxidation state sorting method for the copper-based composite catalyst, satisfies the aforementioned range.

[0040] In the method for selecting the oxidation state of copper-based composite catalysts according to this specification, the ratio (%) of copper with oxidation states of 0 and 1 can be calculated by formula 1, and the ratio (%) of copper with oxidation state of 2 can be calculated by formula 2. The contents of formulas 1 and 2 can be similarly applied to this paragraph as in the description of copper-based composite catalysts mentioned above.

[0041] The oxidation state selection method for copper-based composite catalysts according to one embodiment of this specification can measure the content of a specific oxidation state more accurately by utilizing not only the main peak but also satellite peaks. Furthermore, it has the advantage of being able to accurately determine the copper content for a desired specific oxidation state within the copper-based composite catalyst, even in trace amounts.

[0042] In one embodiment of this specification, the steps of deriving the XPS spectrum of the copper-based composite catalyst may include: deriving the XPS spectrum of the copper-based composite catalyst by X-ray photoelectron spectroscopy (XPS) under conditions of a vacuum atmosphere, a measurement range of 925 eV to 970 eV, and a pass energy of 50 eV; and correcting the peaks of the XPS spectrum.

[0043] In this specification, the copper-based composite catalyst can be expressed as an XPS derivation condition with a pass energy of 50 eV in a measurement range of 925 eV to 970 eV under a vacuum atmosphere. In other words, after deriving the primary XPS spectrum (uncorrected XPS spectrum) of a copper-based composite catalyst by X-ray photoelectron spectroscopy (XPS) in a vacuum atmosphere with a measurement range of 925 eV to 970 eV and a pass energy condition of 50 eV, the peaks of the XPS spectrum can be corrected to derive the secondary XPS spectrum (corrected XPS spectrum) that is the target of analysis in this invention.

[0044] In one embodiment of this specification, the copper-based composite catalyst may be prepared as a sample of a circular pellet with a diameter of 2 mm and a thickness of 1 mm, and the XPS spectrum may be derived from the sample using an Al k-alpha X-ray of size 400 μm × 800 μm under the XPS derivation conditions. That is, a monochromatic Al Kα (1486.6 eV) may be used as the X-ray source when analyzing the XPS spectrum, and the Shirley peak background, ALTHERMO1 sensitivity factor, and TPP-2M energy compensation factor may be applied. Furthermore, the elemental content (atomic percent, at%, based on the total atomic weight of elements present on the surface) of the copper-based composite catalyst surface may be determined using Avantage software.

[0045] In one embodiment of this specification, the step of correcting the peak of the XPS spectrum may involve fixing the CC binding energy for graphite in the carbon 1s spectrum (C 1s spectrum) to a constant energy, and correcting the binding energy for the main peak for copper based on the constant energy. The constant energy can be 284 eV to 285 eV, and most preferably 284.8 eV.

[0046] In one embodiment of this specification, correcting based on a constant energy magnitude may mean correcting the binding energy of the Cu(I) main peak.

[0047] Through the above process, the range of peak binding energy for determining the Cu(II) peak area can be set to 933.3 eV to 936.0 eV, and the range of peak binding energy for determining the peak areas of Cu(0) and Cu(I) can be set to 932.0 eV to 932.8 eV.

[0048] When the range of peak binding energy is set within the aforementioned range, a pure peak can be found. That is, by finding a pure peak unaffected by other factors, the content of oxidation states of copper-based composite catalysts can be selected, thereby increasing the accuracy of the resulting values.

[0049] In one embodiment of this specification, the steps of using the area of ​​the XPS spectrum to calculate the total copper content (at%) and the ratios (%) of copper with oxidation states 0 and 1 and copper with oxidation state 2 are as follows:

[0050] A step of deriving the total copper content on the surface of the copper-based composite catalyst from the XPS spectrum; A step of deriving a first area value from the XPS spectrum as the total area of ​​the main peaks for copper with an oxidation state of 0 and the main peaks for copper with an oxidation state of 1 that occupy the surface of the copper-based composite catalyst; A step of deriving a second area value from the XPS spectrum as the total area of ​​the main peaks for copper with an oxidation state of 2 that occupy the surface of the copper-based composite catalyst; A step of deriving a third area value from the XPS spectrum as the total area of ​​satellite peaks for copper occupying the surface of the copper-based composite catalyst; and The process may include the step of deriving the content (at%) of copper with oxidation states of 0 and 1, and the content (at%) of copper with oxidation state of 2, respectively, using the following formulas 4 and 5.

[0051]

number

number

[0052] In formulas 4 and 5 above at%Cu(0)+Cu(I) is the total content of copper with oxidation state 0 and copper with oxidation state 1 in the copper-based composite catalyst. at%Cu(II) is the total content of copper with an oxidation state of 2 in the copper-based composite catalyst. %Cu(0)+Cu(I) is the ratio (%) of copper with oxidation states of 0 and 1 calculated by formula 1 above. %Cu(II) represents the ratio (%) of copper with an oxidation state of 2, calculated using the above formula 2.

[0053] In this specification, the peaks of Cu(0) and Cu(I) may be expressed as the Cu(0)+Cu(I) peak. For reference, the Cu(0)+Cu(I) peak may represent the main peak for Cu(0) and Cu(I).

[0054] In one embodiment of this specification, the steps for deriving the first area value may include: finding all the main peaks for copper with oxidation state 0 and all the main peaks for copper with oxidation state 1 from the XPS spectrum; and calculating the area values ​​of the main peaks for copper with oxidation state 0 and all the main peaks for copper with oxidation state 1, respectively, and then adding up all the calculated area values.

[0055] In the case of the Cu(0) main peak and Cu(I) main peak, one or more of each may appear in the XPS spectrum. Therefore, accurate measurement is only possible by identifying all of the Cu(0) main peaks and Cu(I) main peaks. Furthermore, since there are parts of the spectrum where the Cu(0) main peak and Cu(I) main peak are difficult to distinguish, the total area value of the Cu(0) main peak and Cu(I) main peak is determined. In the case of Figure 1, there is one Cu(0) main peak or Cu(I) main peak (see Figure 1 reference (1)), but this is an example, and there may be many Cu(0) main peaks or Cu(I) main peaks. The first area value corresponds to the area value of A1 in Figure 1.

[0056] In one embodiment of this specification, the steps for deriving the second area value may include: finding all main peaks for copper with oxidation state 2 from the XPS spectrum; and calculating the area values ​​of each main peak for copper with oxidation state 2, and then adding up all the calculated area values. Since one or more Cu(II) main peaks may appear in the XPS spectrum, accurate measurement is only possible if all Cu(II) main peaks are found. That is, as can be seen in Figure 1, there may be many Cu(II) main peaks (see Figure 1, reference (2) and (3)), so accurate measurement is only possible if all Cu(II) main peaks in the XPS spectrum are found. The second area value corresponds to the area value of A2 in Figure 1.

[0057] In one embodiment of this specification, the steps for deriving the third area value may include: finding all satellite peaks for copper from the XPS spectrum; and calculating the area values ​​of each satellite peak for copper, and then adding up all the calculated area values. Since one or more satellite peaks may appear in the XPS spectrum, accurate measurement is only possible if all satellite peaks are found. That is, as can be seen in Figure 1, there may be many Cu(II) main peaks (see references (4) and (5) in Figure 1), so accurate measurement is only possible if all satellite peaks for the main peak are found in the XPS spectrum. The third area value corresponds to the area value of B in Figure 1.

[0058] In one embodiment of this specification, the satellite peak may be a satellite peak for copper with an oxidation state of 2. This can be expressed as a Cu(II) satellite peak. That is, the Cu(II) satellite peak may represent a satellite peak for copper with an oxidation state of 2 found in the corrected XPS spectrum (second-order spectrum).

[0059] One embodiment of this specification provides a method for selecting the oxidation state of copper-based composite catalysts, characterized by utilizing not only the main peak but also satellite peaks. Therefore, clearly identifying satellite peaks is extremely important for improving the accuracy of the measurement results.

[0060] In one embodiment of this specification, the As / Bs can be 1.5 to 2.1. In one embodiment of this specification, the copper-based composite catalyst may comprise at least one copper oxide and a copper structure, and may further comprise a support. Further details relating thereto can be found in the preceding description of the copper-based composite catalyst, which also applies to this paragraph. For example, the copper composite catalyst may be a Cu-O-Si system catalyst, a Cu-O-Al system catalyst, or a Cu-O-Si-Al system catalyst.

[0061] Furthermore, the Cu-O-Si catalyst is a catalyst containing copper oxide (Cu-O) and a support (silica), and examples include CuO / SiO2, CuO / BaO / SiO2, CuO / ZnO / SiO2, CuO / BaO / SiO2, CuO / ZnO / SiO2, CuO / MnO / SiO2, CuO / Cr2O3 / SiO2, etc., and copper phyllosilicate (...O-Si-O-Cu-O-Si-O-Cu-O...) can be given as an example of a copper-silicate structure catalyst.

[0062] Furthermore, the Cu-O-Al catalyst is a catalyst containing copper oxide and a support (alumina), with CuO / Al2O3 being an example, and copper aluminate (...O-Al-O-Cu-O-Al-O-Cu-O...) being an example of a copper-aluminate structure catalyst. Furthermore, as an example of the Cu-O-Si-Al system, CuO / Al2O3 / SiO2 can be used as a catalyst containing copper oxide and a support (alumina, silica).

[0063] Furthermore, if the copper-based composite catalyst further includes a support, CuO / SiO2 catalyst, CuO / Al2O3 catalyst, CuO x / SiO y The options are (0≦x<1, 0≦y<2) and CuOx / AlOy (0≦x<1, 0≦y<1.5). The copper-based composite catalysts mentioned above are illustrative examples and are not limiting.

[0064] The copper-based composite catalyst produced according to the present invention can be used as a catalyst for the production of neopentyl glycol. In this case, in one embodiment of this specification, the method for producing the neopentyl glycol can be a method known in the art, except that the copper-based composite catalyst according to the present invention is used.

[0065] More specifically, one embodiment of this specification provides a method for producing neopentyl glycol, comprising the step of introducing a hydroxypivaldehyde (HPA) solution and hydrogen into a hydrogenation reactor to carry out a hydrogenation reaction, wherein the hydrogenation reactor contains a copper-based composite catalyst according to the present invention.

[0066] For example, the hydrogenation reactor may be a fixed-bed reactor (FBR) packed with the copper-based composite catalyst (catalyst for neopentyl glycol production). In this case, there is no need to separate the catalyst from the reaction product, the reaction temperature and pressure can be lowered compared to conventional methods, resulting in stable and economical operation, easy catalyst replacement, and a smaller reactor size, which significantly reduces investment costs.

[0067] In one embodiment of this specification, the hydroxypivaldehyde solution may contain 50% to 80% by weight of hydroxypivaldehyde, 1% to 5% by weight of neopentyl glycol, 15% to 35% by weight of alcohol, and 1% to 10% by weight of water. In this case, the reaction heat can be minimized without reducing reactivity, and the formation of by-products can be suppressed.

[0068] Furthermore, in one embodiment of this specification, the hydrogenation reaction may have a reaction temperature of 100°C to 250°C, preferably 100°C to 200°C, and more preferably 100°C to 180°C.

[0069] Furthermore, in one embodiment of this specification, the hydrogenation reaction may have a reaction pressure of 35 bar or higher. The reaction pressure refers to the measured pressure.

[0070] When applying a catalyst for neopentyl glycol production according to one embodiment of this specification to the production of neopentyl glycol, it is possible to prevent the elution of catalyst components (e.g., copper components) into the neopentyl glycol solution produced.

[0071] Therefore, when applying a catalyst for the production of neopentyl glycol according to one embodiment of this specification to the production of neopentyl glycol, the purification step by eluting catalyst components (e.g., copper components) becomes unnecessary, extending the catalyst life and reducing production costs. [Examples]

[0072] The present invention will be described in detail below with reference to examples. However, the examples of the present invention may be modified in various forms, and the scope of the present invention should not be construed as being limited to the following examples. The examples of the present invention are provided to give a more complete explanation of the present invention to a person of average skill in the industry.

[0073] Experimental Example 1. Evaluation of a method for selecting copper-based composite catalysts by oxidation state. <Example 1-1> As shown in Table 1 below, the Cu-O-Si copper composite catalyst was manufactured by the following process: Co-precipitation was performed using copper nitrate, silica sol, and an alkaline precipitating agent to obtain a precipitated powder. The wt% ratio of Cu / Si added was 30:70 = 0.43. Subsequently, the powder was dried through a filtration and rinsing and drying process.

[0074] To analyze the Cu oxidation state ratio on the catalyst surface, Cu-O-Si copper composite catalyst samples were produced by manufacturing circular pellets with a diameter of 2 mm and a thickness of 1 mm, and then calcining them.

[0075] The aforementioned sample was placed in an XPS (X-ray Photoelectron Spectroscopy) analyzer (model name / manufacturer: Nexsa / Thermo Scientific) and placed in a vacuum atmosphere (~10°C). -7Using an Al K-alpha X-ray with a torr of 1486.6 eV, measurements were taken with a 400 μm × 800 μm X-ray size in the measurement range of 925 eV to 970 eV, with a pass energy of 50 eV, to first derive the copper 2p spectrum (Cu 2p spectrum). Subsequently, the binding energy of the derived spectrum was corrected to match the graphite CC binding energy of 284.8 eV, which is the reference for the carbon 1s spectrum (C 1s spectrum), to derive the XPS spectrum shown in Figure 1.

[0076] Using the Shirley method to set the background in the aforementioned XPS spectrum, the first area value (A1) of the Cu(0) main peak representing copper with oxidation state 0 or the Cu(I) main peak representing copper with oxidation state 1, the second area value (A2) which is the total area of ​​the Cu(II) main peak representing copper with oxidation state 2, and the third area value (B) of the Cu(II) satellite peak representing the satellite peak for copper with oxidation state 2 were calculated by fitting using the Lorentzian / Gaussian (L / G) function and FWHM (Full Width Half Maximum).

[0077] The specific ratio of the Lorentzian / Gaussian (L / G) functions was set to 70 / 30, and the FWHM fit parameters were set to 0.5:3.5. The derivation of the XPS spectrum, background setting, and fitting process were performed using the Avantage software program.

[0078] Next, after determining the first to third area values, the ratio of copper with oxidation state 2 in the copper-based composite catalyst of Production Example 1 was calculated using Equation 2 below. Furthermore, the ratio of copper with oxidation state 0 to copper with oxidation state 1 was calculated using Equation 1.

[0079] The meanings of the symbols in Formulas 1 and 2 are as follows. As / Bs was set to 1.89, a known average value for CuO, because the sample used in Example 1-1 is a Cu-O-Si catalyst and contains Cu-O bonds.

[0080]

number

number

[0081] In the above formulas 1 and 2, Cu(0), Cu(I), and Cu(II) represent copper with an oxidation state of 0, copper with an oxidation state of 1, and copper with an oxidation state of 2, respectively.

number

[0082] The total content of copper with oxidation state 0 and copper with oxidation state 1, and the total content of copper with oxidation state 2, on the surface of the copper composite catalyst of Example 1-1 were calculated using the following equations 4 and 5, based on the copper content (at%) measured by XPS and the ratio values ​​of copper oxidation states calculated using equations 1 and 2. The meanings of the symbols in equations 4 and 5 are as follows, and the resulting values ​​are shown in Table 1 below.

[0083]

number

number

[0084] In equations 4 and 5, at%(Cu(0)+Cu(I)) is the total content of copper with oxidation state 0 and copper with oxidation state 1 in the copper-based composite catalyst. at%Cu(II) is the total content of copper with an oxidation state of 2 in the copper-based composite catalyst. %(Cu(0)+Cu(I)) is the ratio (%) of copper with oxidation states of 0 and 1 calculated by formula 1 above. %Cu(II) represents the ratio (%) of copper with an oxidation state of 2, calculated using the above formula 2.

[0085] <Examples 1-2 and 1-3> The added Cu / Si weight ratio (wt% ratio) was 30:70 = 0.43. The total content of copper with oxidation state 0 and copper with oxidation state 1, and the total content of copper with oxidation state 2 on the surface of the copper-based composite catalysts of Examples 1-2 and 1-3 were calculated using the same method as in Example 1-1. The results are shown in Table 1 below. Furthermore, the XPS spectra of Examples 1-2 and 1-3 are shown in Figures 2 and 3, respectively.

[0086] <Comparative Example 1-1> Using the same copper-based composite catalyst as in Example 1-1, the XPS spectrum was derived using the same method as in Example 1-1. However, unlike Example 1-1, the background was set and fitting was performed without considering satellite peaks.

[0087] As a result, as shown in Figure 4, it was confirmed that the surface was fitted in a way that showed no area of ​​Cu(0) and Cu(I) main peaks (A1) and satellite peaks (B) indicating copper with oxidation state 0 or 1, and only the total area of ​​Cu(II) main peak (A2) indicating copper with oxidation state 2. In other words, in the case of Comparative Example 1-1, despite using the same catalyst as in Example 1, the ratio of copper with oxidation state 0 to copper with oxidation state 1 could not be measured.

[0088] Next, the proportion of copper with an oxidation state of 2 was measured from the fitting results shown in Figure 4. The results are shown in Table 1 below.

[0089] <Comparative Example 1-2> The copper oxidation state content in the copper-based composite catalyst was measured using the same method as in Comparative Example 1-1, except that the same copper-based composite catalyst as in Example 1-2 was used.

[0090] In other words, as shown in Figure 5, in Comparative Example 1-2, there were no main peak areas (A1) and satellite peak areas (B) for Cu(0) and Cu(I) indicating copper with oxidation states of 0 or 1, and therefore the ratio of copper with oxidation state 0 to copper with oxidation state 1 could not be measured. The ratio of copper with oxidation state 2 was measured from the fitting results shown in Figure 5. The results are shown in Table 1 below.

[0091] [Table 1]

[0092] From the results in Table 1 above, it was confirmed that when following the sorting method according to the present invention (Examples 1-1 to 1-3), more accurate values ​​for the copper content based on oxidation state can be obtained than when not following the sorting method according to the present invention (Comparative Examples 1-1 and 1-2).

[0093] In other words, if satellite peaks are not considered, the area (A1) of the main Cu(0) and Cu(I) peaks, which represent copper with oxidation states of 0 or 1, does not exist, making it impossible to derive the result and therefore the content of copper with oxidation states of 0 or 1 could not be confirmed. Furthermore, because the content of copper with oxidation states of 0 or 1 could not be confirmed, the content of copper with oxidation state 2 was also measured inaccurately.

[0094] Experimental Example 2. Evaluation of the physical properties of copper-based composite catalysts. <Examples 2-1 and 2-2> The Cu-O-Si catalysts of Examples 1-1 and 1-3 were used as copper-based composite catalysts to evaluate their physical properties.

[0095] <Example 2-3> A Cu-O-Al-based catalyst was used as the copper-based composite catalyst for evaluating its physical properties, and the catalyst was manufactured using the same selection method described in Example 1-1.

[0096] Furthermore, the copper-based composite catalyst was produced in the same manner as described in Example 1-1, except that copper nitrate, alumina sol, and an alkaline precipitant were added by co-precipitation to produce a precipitated powder with a Cu / Al weight percentage ratio of 30:70.

[0097] <Comparative Example 2-1> The Cu-O-Si catalysts from Examples 1-2 were used as copper-based composite catalysts to evaluate their physical properties.

[0098] <Comparative Example 2-2> The Cu-O-Al catalyst was prepared in the same manner as described in Example 2-3, except that the Cu / Al weight percentage ratio was 15:85 to produce the precipitated powder.

[0099] <Comparative Example 2-3> A Cu-O-Al catalyst was produced in the same manner as described in Example 2-3, except that a precipitate powder was prepared by adding Cu / Al in a weight percentage ratio of 15:85, and a hydrothermal treatment at 150°C was added to increase the proportion of Cu(II).

[0100] <Comparative Example 2-4> The Cu-O-Al catalyst was manufactured in the same manner as described in Examples 2-3, except that a hydrothermal treatment at 150°C was added to increase the proportion (%) of Cu(II).

[0101] As shown in Table 2 below, the content of copper with oxidation state 0, copper with oxidation state 1, and copper with oxidation state 2 in the Cu-O-Al copper composite catalyst was calculated using the same method as in Example 1-1, and the results are as follows. Furthermore, the XPS spectra for Comparative Examples 2-2, 2-3, Example 2-3, and Comparative Example 2-4 are shown in Figures 6 to 9, respectively.

[0102] [Table 2]

[0103] Experimental Example 2-1. Evaluation of Hydrogen Consumption Rate (Physical Property Evaluation 1) Using a Buchi autoclave, 100 g of a Feed solution (HPA:2-EH=1:4) for producing neopentyl glycol (NPG) and 3 cc of the copper-based composite catalysts from Examples 2-1 to 2-3 and Comparative Examples 2-1 and 2-2 were placed in the reactor, and after reduction treatment with hydrogen at 180°C, hydrogen was consumed at a rate of (ml / min·g) at 30 bar and 115°C. cat ) was measured and evaluated.

[0104] In this study, the hydrogen consumption rate measured in Example 2-1 was used as the baseline (100%), and the hydrogen consumption rates of Examples 2-2, 2-3, and Comparative Examples 2-1 and 2-2 were converted to percentages relative to Example 2-1 (referred to as relative hydrogen consumption rates) for comparative evaluation. The evaluation results are shown in Table 3 below.

[0105] [Table 3]

[0106] According to Table 3, the copper-based composite catalyst according to the present invention (Examples 2-1 to 2-3), which contains 2.5 at% to 7.5 at% copper relative to the surface, and includes 10% to 50% of copper with oxidation state 0 and copper with oxidation state 1, and 50% to 90% of copper with oxidation state 2, exhibits a hydrogen consumption rate exceeding 90%, while the hydrogen consumption rate is below 90% compared to copper-based composite catalysts that do not meet the above content (at%) and ratio (%). Therefore, it was confirmed that the above content and ratio are significant components for the reactivity of the copper-based composite catalyst. In particular, the difference was even more pronounced when comparing the examples and comparative examples of catalysts in the same series with each other.

[0107] Experimental Example 2-2. Evaluation of Strength Reduction Rate (Physical Property Evaluation 2) <Comparative Example 3-1> The copper-based composite catalyst before hydrothermal treatment in Comparative Example 2-2 and the copper-based composite catalyst after hydrothermal treatment in Comparative Example 2-3 were compared.

[0108] The strength of the catalyst was evaluated (in N) before and after hydrothermal treatment. Specifically, for the hydrothermal treatment, 100 ml of water (H2O) and the copper-based composite catalyst before hydrothermal treatment were placed in an autoclave and maintained at a temperature of 150°C for 3 hours. The pressure inside the autoclave was set to a high pressure of 10-20 bar. The evaluation results of the strength reduction rate are shown in Table 4 below, and the strength reduction rate was calculated as a percentage (%) of "(strength measured before hydrothermal treatment - strength measured after hydrothermal treatment) / strength before hydrothermal treatment".

[0109] <Example 3-1> Except for comparing the copper-based composite catalyst before hydrothermal treatment in Example 2-3 with the copper-based composite catalyst after hydrothermal treatment in Comparative Example 2-4, the strength reduction rate evaluation was performed using the same method as in Comparative Example 3-1, and the results are shown in Table 4 below. [Table 4]

[0110] According to Table 4, the copper-based composite catalyst according to the present invention (Example 2-3) in its pre-hydrothermal treatment state, containing 2.5 at% to 7.5 at% copper relative to the surface, with 10% to 50% of copper with oxidation state 0 and copper with oxidation state 1, and 50% to 90% of copper with oxidation state 2, shows a strength reduction rate of 0% after hydrothermal treatment (see Example 3-1), whereas the copper-based composite catalyst in its pre-hydrothermal treatment state that does not satisfy the above content (at%) and ratio (%) shows a strength reduction rate of 96% (see Comparative Example 3-1).

Claims

1. The surface contains copper in an amount of 2.5 at% to 7.5 at%. The copper includes copper with an oxidation state of 0 and copper with an oxidation state of 1 in a ratio of 10% to 50%, and copper with an oxidation state of 2 in a ratio of 50% to 90%. The above content and ratio are obtained by the copper-based composite catalyst by the following method 1: [Method 1] An XPS spectrum was obtained for the surface of a copper-based composite catalyst, including the main peak for copper with oxidation state 0, the main peak for copper with oxidation state 1, the main peak for copper with oxidation state 2, and a satellite peak for copper. The area of ​​the XPS spectrum is used to obtain the total copper content (at%) and the ratio (%) of copper with oxidation states 0 and 1, and copper with oxidation state 2, respectively.

2. The ratio (%) of copper with oxidation states of 0 and 1 is calculated by the following formula 1: The ratio (%) of copper with an oxidation state of 2 is calculated by the following formula 2, according to the copper-based composite catalyst of claim 1: [Math 1] [Math 2] In the above formulas 1 and 2, Cu(0), Cu(I), and Cu(II) represent copper with an oxidation state of 0, copper with an oxidation state of 1, and copper with an oxidation state of 2, respectively. [Math 3] Satisfying the conditions, A1 is the sum of the total area of ​​the Cu(0) main peaks calculated by the XPS spectrum and the total area of ​​the main peaks for Cu(I). A2 is the total area of ​​the Cu(II) main peaks calculated by the XPS spectrum. B is the total area of ​​satellite peaks for Cu(II) calculated by XPS spectroscopy. As / Bs is Cu(II) Cu 2p ３／２ This represents the area ratio of the main peak to the satellite peak relative to the total area.

3. The copper-based composite catalyst according to claim 1, wherein the surface refers to a region with a depth of 0 nm to 10 nm in the central direction at the interface of the copper-based composite catalyst that comes into contact with the atmosphere.

4. The copper-based composite catalyst according to claim 1, wherein the copper-based composite catalyst comprises at least one of a copper oxide and a copper structure.

5. The copper-based composite catalyst according to claim 4, further comprising a support.

6. A step of obtaining an XPS spectrum for the surface of a copper-based composite catalyst, including a main peak for copper with oxidation state 0, a main peak for copper with oxidation state 1, a main peak for copper with oxidation state 2, and a satellite peak for copper; and A step in which the total copper content (at%) and the ratios (%) of copper with oxidation states 0 and 1, and copper with oxidation state 2 are calculated using the area of ​​the XPS spectrum; A method for selecting the oxidation state of copper-based composite catalysts, including [the specified component].

7. The ratio (%) of copper with oxidation states of 0 and 1 is calculated by the following formula 1: The ratio (%) of copper with an oxidation state of 2 is calculated by the following formula 2, according to the method for selecting the oxidation state of a copper-based composite catalyst according to claim 6: [Math 4] [Math 5] In the above formulas 1 and 2, Cu(0), Cu(I), and Cu(II) represent copper with an oxidation state of 0, copper with an oxidation state of 1, and copper with an oxidation state of 2, respectively. [Math 6] Satisfying the conditions, A1 is the sum of the total area of ​​the main peaks for Cu(0) and the total area of ​​the main peaks for Cu(I) calculated by the XPS spectrum. A2 is the total area of ​​the Cu(II) main peaks calculated by the XPS spectrum. B is the total area of ​​satellite peaks for Cu(II) calculated by XPS spectroscopy. As / Bs is Cu(II) Cu 2p ３／２ This represents the area ratio of the main peak to the satellite peak relative to the total area.

8. The step of obtaining an XPS spectrum (spectrum) for the surface of the copper-based composite catalyst is: The steps include: deriving the XPS spectrum of the copper-based composite catalyst by X-ray photoelectron spectroscopy (XPS) under vacuum conditions, a measurement range of 925 eV to 970 eV, and a pass energy of 50 eV; and A step of correcting the peak of the XPS spectrum; A method for selecting the oxidation state of a copper-based composite catalyst according to claim 6, including the method described in claim 6.

9. The step of correcting the peak of the XPS spectrum is as follows: A method for selecting the oxidation state of a copper-based composite catalyst according to claim 8, wherein the C-C bond energy for graphite in the carbon 1s spectrum (C 1s spectrum) is fixed to a certain magnitude of energy, and the bond energy for the main peak for copper is corrected based on the said constant magnitude of energy.

10. The step of using the area of ​​the XPS spectrum to calculate the total copper content (at%) and the ratio (%) of copper with oxidation states 0 and 1, and copper with oxidation state 2, respectively, is as follows: A step of deriving the total copper content on the surface of the copper-based composite catalyst from the XPS spectrum; A step of deriving a first area value from the XPS spectrum as the total area of ​​the main peaks for copper with an oxidation state of 0 and the main peaks for copper with an oxidation state of 1 that occupy the surface of the copper-based composite catalyst; A step of deriving a second area value from the XPS spectrum as the total area of ​​the main peaks for copper with an oxidation state of 2 that occupy the surface of the copper-based composite catalyst; A step of deriving a third area value from the XPS spectrum as the total area of ​​satellite peaks for copper on the surface of the copper-based composite catalyst; and The following steps involve deriving the content (at%) of copper with oxidation states 0 and 1, and the content (at%) of copper with oxidation state 2, respectively, using formulas 4 and 5 below; A method for selecting the oxidation state of a copper-based composite catalyst according to claim 6, including: [Number 7] [Number 8] In the above formulas 4 and 5, at% (Cu(0) + Cu(I)) is the total content of copper with oxidation state 0 and copper with oxidation state 1 in the copper-based composite catalyst. at%Cu(II) is the total content of copper with an oxidation state of 2 in the copper-based composite catalyst. %(Cu(0) + Cu(I)) is the ratio (%) of copper with oxidation states of 0 and 1 calculated by formula 1 above. %Cu(II) represents the ratio (%) of copper with an oxidation state of 2, calculated by formula 2 above.

11. The step of deriving the first area value is: The step of finding all the main peaks for copper with an oxidation state of 0 and for copper with an oxidation state of 1 from the XPS spectrum; and The first step is to calculate the area values ​​of the main peak for copper with an oxidation state of 0 and the main peak for copper with an oxidation state of 1, and then add up all the calculated area values; A method for selecting the oxidation state of a copper-based composite catalyst according to claim 10, including the method described in claim 10.

12. The step of deriving the second area value is: The step of finding all the main peaks for copper with an oxidation state of 2 from the XPS spectrum; and After calculating the area values ​​of the main peaks for copper with an oxidation state of 2, the area values ​​are all added together; A method for selecting the oxidation state of a copper-based composite catalyst according to claim 10, including the method described in claim 10.

13. The step of deriving the third area value is: The step of finding all satellite peaks for copper from the XPS spectrum; and After calculating the area values ​​of the satellite peaks for each of the aforementioned copper regions, the next step is to add up all of the calculated area values; A method for selecting the oxidation state of a copper-based composite catalyst according to claim 10, including the method described in claim 10.

14. The method for selecting the oxidation state of a copper-based composite catalyst according to claim 7, wherein the As / Bs ratio is 1.5 to 2.

1.

15. The method for selecting the oxidation state of a copper-based composite catalyst according to claim 6, wherein the satellite peak for copper is the satellite peak for copper with an oxidation state of 2.

16. The method for selecting the oxidation state of a copper-based composite catalyst according to claim 6, wherein the copper-based composite catalyst comprises at least one of a copper oxide and a copper structure.

17. The method for selecting the oxidation state of a copper-based composite catalyst according to claim 16, further comprising a support.

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