JP2000351775A - Production of 2-p-dioxanone - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a new 2-p-dioxanone stably for a long period of time in a high conversion rate and in a high selectivity by bringing a loaded copper catalyst in which the dispersed particle diameter of the copper is controlled as smaller than a specific size, in contact with diethylene glycols in the presence of hydrogen. SOLUTION: This 2-p-dioxanone is obtained by bringing (A) a catalyst consisting of copper loaded on a carrier (preferably a silica) having 2x10-7 equivalent/m2 total amount of acid points having >=1.5 acid strength <=0.5 μm maximum particle diameter of the loaded copper, in contact with (B) diethylene glycols [preferably diethylene glycol, 2,2'-oxybis(1-propanol), etc.], in the presence of hydrogen. Further, the above contact is preferably performed under a gas phase flow in view of production efficiency. Thereby, it is expected that the high conversion rate and a high selectivity are realized simultaneously and the objective compound can be synthesized for a long period of time.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for producing 2-p-dioxanones using diethylene glycols as raw materials and using a specific catalyst.

[0002]

2. Description of the Related Art 2-p-dioxanones are used as raw materials (monomers) for polymerizing polymers. In particular, 2-p-dioxanone is useful as a raw material for polymerizing poly (2-p-dioxanone) used as a surgical suture having bioabsorbable properties. Poly (2-p-dioxanone) is also useful as a recyclable material because it easily depolymerizes under heating and gives 2-p-dioxanone as a polymerization raw material almost quantitatively and with high purity. .

[0003] In connection with the problem of treating plastic waste, which has become a major social problem at present, the necessity of recycling plastic materials has been recognized, and poly (2), which is safe and has depolymerization properties, has been developed. -P-dioxanone) is attracting attention as an effective recycled material.

As a method for producing such 2-p-dioxanones, a vaporized diethylene glycol is brought into contact with a catalyst in the presence of hydrogen gas, and the desired product is obtained by a dehydrogenation and cyclization reaction represented by the following formula. A method of obtaining is known (US Pat. No. 5,310,945).

[0005]

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The dehydrogenation catalyst used here is a catalyst in which alumina, a basic component such as copper, zinc, and potassium are supported on alumina, and is subjected to heat treatment in a reducing atmosphere and then contacted with diethylene glycols. It has been used.

However, when the present inventors conducted a gas-phase flow reaction of 2-p-dioxanone using the catalyst disclosed in the above-mentioned US Patent, the conversion was high at the initial stage, but the reaction was continued. It was clarified that the conversion was reduced in a relatively short time when performed.

Specifically, a temperature of 300 ° C. and a space velocity (L
When the reaction was carried out under the conditions of (HSV) 2.0 h ^-1 , the initial conversion was as high as 100%, but the conversion after continuous reaction for 12 hours was 88% and further 100 hours. It was found to drop to 22% after continuing the reaction.

[0009] As a method for solving the above catalyst life problem, we propose that copper is added to a carrier having an acid strength (H ₀ ) of greater than 1.5 and a total amount of acid sites of 2 × 10 ^-7 equivalents per square meter or less. A technique for using a supported catalyst to allow hydrogen to coexist during the reaction has been proposed (JP-A-10-120675).

[0010]

Although the catalyst life is greatly improved by the above technology, the effect is not always sufficient, and the selectivity decreases over time, and the production time of each catalyst production lot increases. It turned out that there was a new problem that the performance varied.

Accordingly, an object of the present invention is to provide a method for producing 2-p-dioxanones stably with high conversion and high selectivity over a long period of time.

[0012]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies in order to solve the above-mentioned problems, and as a result, the above-mentioned Japanese Patent Application Laid-Open No.
In the supported copper catalyst disclosed in JP-A-120675, it has been found that the above object can be achieved when the dispersed particle diameter of copper is controlled to be a specific size or less. The invention has been completed.

[0013] Namely, the present invention, the total amount of acid strength (H ₀₎ strong acid than 1.5 2 × 10 ^- and ⁷ catalyst copper equivalents per square meter or less as a carrier is carried and diethylene glycols In the presence of hydrogen to give 2-p
-A method for producing dioxanones, wherein a catalyst having a maximum particle diameter of supported copper of 0.5 µm or less is used.

In the present invention, the term "suppression of a decrease in the conversion over time" obtained by carrying out a reaction in the presence of hydrogen using a supported copper catalyst using a carrier having a small number of acid sites having a strong acid strength is referred to. In addition to the effects, excellent effects such as prevention of decrease in selectivity and prevention of variation in catalyst performance can be obtained.

In general, it is known that in a supported metal catalyst, the activity of the catalyst is improved by reducing the particle size of the supported metal. However, the relationship between the particle size of the metal and the selectivity depends on the catalyst and the reaction. It depends on the type. In the present invention,
As the supported copper is refined to the order of nanometers, changes such as a single active site occur,
The present inventors presume that such an effect has been obtained.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION Diethylene glycols used in the present invention refer to compounds having a chemical structure represented by the following formula.

[0017]

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In the above formula, R and R 'are a hydrogen atom or an alkyl group having 1 to 12 carbon atoms. From the viewpoints of reactivity and usefulness of the polymer obtained by polymerization, R is a hydrogen atom or an alkyl group having 1 to 8 carbon atoms, and R ′ is preferably a hydrogen atom. More preferably, it is a hydrogen atom or an alkyl group having 1 to 2 carbon atoms.

Preferred examples of diethylene glycols include diethylene glycol, 2,2'-oxybis (1-propanol), 2,2'-oxybis (1-butanol) and 2,2'-oxybis (1-pentanol). ), 2,2′-oxybis (1-hexanol) and the like, each of which can be used alone or in combination of two or more.

Of these, the one in which the reaction proceeds most rapidly is diethylene glycol, and it is most preferable to use diethylene glycol.

In the present invention, as shown in the following formula, diethylene glycols are dehydrogenated and cyclized in a molecule to obtain 2-p-dioxanones having a corresponding structure.

[0022]

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In the present invention, the acid properties of the carrier include:
The total amount of acid sites having an acid strength (H ₀ ) of more than 1.5 is 2 × 10
^{- 7} It is important to use a supported copper catalyst using equivalent per square meter (eq / m ²⁾ or less is carrier.

When a carrier having an acid strength (H ₀ ) higher than 1.5 and a total amount of acid sites exceeding 2 × 10 ⁻⁷ eq / m ² is used, the dehydration reaction, which is a side reaction, predominates, The product dioxane is produced in large quantities. In addition, the deterioration of the catalyst activity due to the attachment of the carbon compound progresses violently, and the reaction yield decreases within a short time. In the present invention, from the viewpoint of the effect, acid strength (H ₀₎ is the total amount of strong acid from 1.5 1 × 10 ^- it is preferred to use the carrier is ⁷ eq / m ² or less.

Here, the “acid strength (H ₀ ) of the carrier is 1.5
The term “total amount of stronger acid sites” refers to the total number of acid sites determined by the amine titration method (indicator method) described in “Catalysis Engineering Course 4: Basic Catalyst Measurement Method” (edited by the Catalysis Society of Japan), page 161 et seq. means.

That is, when the carrier was dispersed or precipitated in a benzene solvent, benzeneazodiphenylamine having a pka of 1.5 was added as an indicator, and titration with normal butylamine required that the surface of the carrier change from purple to yellow. It means the value obtained by dividing the titer (equivalent number) by the total surface area of the carrier used as a sample. Here, the surface area of the carrier is a value obtained by a normal BET measurement method.

The carrier used in the present invention has an acid strength (H ₀ ) of more than 1.5 with a total amount of acid sites of 2 × 10 ⁻⁷ eq.
/ M ² or less, and are not particularly limited, and metal oxides such as alumina, silica, zirconia, and titania that are generally used as catalyst carriers; zeolite, and composite oxides such as silica-alumina Clays such as kaolinite and montmorillonite; and other solid compounds such as activated carbon may be appropriately selected and used according to the above-mentioned titration method so as to satisfy the above-mentioned acidity conditions.

In general, it is well known that the acidity of a carrier of the same kind varies depending on the production method and treatment. However, silica, zirconia and titania are usually used in the above-mentioned acid irrespective of the production method and treatment method. Meet the property requirements. on the other hand,
The acid properties of the composite oxide vary greatly depending on the composition. However, silica / zirconia having a zirconia content of 85% or more and silica / alumina having an alumina content of 5% or less usually satisfy the above acid property conditions. In addition, the clays generally satisfy the above-mentioned acidity conditions as long as they are not substituted with cations. Among them, silica is most preferably used because it has a large surface area and is easily available.

Incidentally, the total amount of acid points of general alumina having an acid strength (H ₀ ) of more than 1.5 is 2 × 10 ⁻⁷ e
q / m ^2, and the effect of the present invention cannot be obtained when such alumina is used as a carrier.

The carrier used in the present invention can be used without any limitation as long as it satisfies the above-mentioned acid property conditions. However, in order to increase the probability of contact with the reaction raw material diethylene glycol, a porous carrier is used. A carrier is preferably used. For silica, the pore volume, various supports having different pore sizes are easily available, and the pore volume is 0.3
Those having a pore diameter of from 1.0 to 1.0 ml / g and a pore diameter of from 2 to 200 nm are preferably used. Generally, the pore volume is large and the pore size is small as the pore size tends to be large. However, it can be appropriately selected and used in consideration of the compression strength of the carrier and the like. Further, in the present invention, it is necessary to use a supported copper catalyst having a maximum supported copper particle diameter of 0.5 μm or less.
When this condition is not satisfied, the conversion rate decreases with time even if a carrier that satisfies the above acid property conditions is used,
It is inevitable that the catalyst performance varies for each production lot. From the point of view of effect, the maximum particle size of the supported copper is 0.3
It is preferable that it is not more than μm.

Here, the maximum particle size of the supported copper is determined by observing the copper existing on the surface outside the pores of the carrier by a scanning electron microscope (SEM) and by examining the copper existing inside the pores of the carrier. Can be evaluated by observation with a transmission electron microscope (TEM). Since it is clear that the particle size of the copper present inside the pores of the carrier is not more than the pore diameter of the carrier, when using a carrier whose maximum pore diameter is clearly smaller than 0.5 μm, The maximum particle size of the supported copper can be easily determined by observing the surface of the carrier by SEM.

The preparation of a supported copper catalyst that satisfies such copper dispersion conditions can be carried out by employing a supporting method such as an impregnation method, an ion exchange method, or a precipitation-deposition method. Among these supporting methods, it is preferable to use the impregnation method from the viewpoint of simplicity of operation.

For example, the carrier is immersed in a solution of a predetermined amount (usually equal to the pore volume of the carrier) obtained by dissolving a copper compound in water or an organic solvent, and dried to allow the inside of the pores of the carrier to be dried. A copper compound is precipitated to obtain a catalyst precursor, the catalyst precursor is treated with an aggregation inhibitor, dried, calcined in the presence of oxygen, and the precipitated copper compound is once converted into copper oxide, and further reduced to hydrogen or the like. It can be suitably prepared by treating and reducing with an inert gas.

The copper compound used here includes copper nitrate, copper chloride, copper acetate, copper carbonate, copper acetylacetonate complex, copper carbonyl, and the like. Copper nitrate is most preferably used because of its ease.

The amount of the copper compound to be used is not particularly limited, but is expressed in terms of the amount of copper carried and 0.1 to the total weight of the catalyst.
It is preferred that the amount is from 40 to 40% by weight, especially from 0.5 to 20% by weight. When the supported amount of copper is less than 0.1% by weight, the reaction rate is remarkably reduced, which is not practical. Further, even when copper is supported in an amount exceeding 40% by weight, the surface area of copper per supported weight is reduced, and not only the effect of increasing the supported amount is lost but also the copper is easily aggregated. Most preferably, the supported amount of copper is 1 to 10% by weight in view of activity and ease of preparation.

In addition, as a coagulation inhibitor for suppressing copper from moving out of the carrier pores and coagulating when the catalyst precursor is calcined after supporting and drying the copper compound, inorganic coagulants such as ammonia are used. Amines or organic amines such as ethylenediamine, diethylenetriamine and triethylenetetraamine are used.

The method of treatment with the aggregation inhibitor is not particularly limited as long as the precipitated copper compound can be brought into contact with the aggregation inhibitor. Regarding the coagulation inhibitor easily gasified such as ammonia, the catalyst precursor is subjected to treatment by fertilization. In addition, with respect to the aggregation inhibitor which is liquid or soluble in a solvent, the amount of the aggregation inhibitor in the form of a liquid or a solution equal to the pore volume of the carrier and the catalyst precursor are mixed with stirring to remove the excess treating agent. A drying method can be adopted. From the viewpoint of ease of treatment, it is most preferable to use ammonia as the aggregation inhibitor.

In the treatment, the amount of the coagulation inhibitor used is preferably in the range of 0.5 to 6.0 times in terms of the equivalent number of amino groups to the supported copper compound. When the amount is less than 0.5 equivalent, the effect of suppressing aggregation is insufficient, and when the amount exceeds 6.0 equivalent, not only the effect of suppressing aggregation does not change but also it is difficult to remove an excessive amount of the aggregation inhibitor. Becomes

The catalyst precursor treated for suppressing aggregation is calcined at 300 to 800 ° C. in the presence of oxygen, and is heated in a reducing atmosphere to reduce copper to zero valence or monovalent just before use in the reaction. As a result, the catalyst has catalytic activity for the dehydrogenation reaction. The reducing atmosphere refers to an atmosphere in which hydrogen, ammonia, carbon monoxide, or any of these gases is diluted with an inert gas. The heating conditions are 200-600 ° C.
Is appropriate.

The supported copper catalyst used in the present invention may contain other metal components as long as the reaction is not inhibited. Illustrative of these metal components are zinc, platinum,
Palladium and chromium. These metals do not necessarily need to be added at the time of catalyst preparation, and may be added, for example, to the reaction substrate.

In the present invention, 2-p-dioxanones are produced by bringing the catalyst obtained as described above into contact with diethylene glycols in the presence of hydrogen gas. When hydrogen does not coexist, not only is the generation of carbon as a by-product remarkable, but also a carbon compound gradually adheres to the surface of the catalyst, causing deterioration of the catalyst activity.

At this time, the amount of coexisting hydrogen is not particularly limited, but considering the effect of extending the life of the catalyst and the operability, 0.1 to 2 mol per mol of diethylene glycol.
It is preferably 0 mol. More preferably, 0.5
10 to 10 mol. Note that hydrogen may be supplied after being diluted with an inert gas such as nitrogen.

The condition for contacting the diethylene glycols with the catalyst is preferably a temperature of 200 to 400 ° C., more preferably 250 to 350 ° C. If the temperature is lower than 200 ° C., the conversion is low, and if the temperature exceeds 400 ° C., the side reaction proceeds more actively. Pressure is 300mmH
The range of g to 5 atm is preferable, and the range of normal pressure to 2 atm is more preferable. If it is less than 300 mmHg, the conversion rate is low and 5
This is because when the pressure exceeds the atmospheric pressure, the side reaction proceeds more actively.

The above-mentioned contact may be carried out in a liquid phase or in a gas phase, but from the viewpoint of production efficiency, it is preferable to carry out the contact in a gas phase. The space velocity at this time is LHSV
[Raw material in standard condition supplied per hour (ml liquid)
/ Volume of catalyst layer (ml)] is preferably in the range of 0.1 to 10 h ^-1 and is preferably 0.1 to 5 h ^-1 from the viewpoint of preventing isomerization of the product and the conversion. More preferred.

The reactor used in the present invention is not particularly limited. For example, when performing a fixed bed gas phase flow type reaction, the reactor may be a vertical type or a horizontal type, and if it is a vertical type, the reaction substrate may be passed from top to bottom or from bottom to top. The material of the reaction device is not particularly limited as long as it can withstand the above-described temperature and pressure and does not contain a component that inhibits the reaction.
Those made of stainless steel (SUS) or glass can be used as appropriate. The reaction product in the synthesis reaction of 2-p-dioxanone may be directly analyzed by collecting the mixed gas of the product while keeping it warm, or may be a liquid crude separated and condensed from hydrogen and nitrogen gas by cooling. 2-p-dioxanone may be analyzed. The analysis is suitably performed by gas chromatography (GC) or liquid chromatography (LC). The conversion and selectivity are calculated from the values obtained by correcting the peak areas of the respective components of GC or LC with the detection sensitivity. In the present invention, the conversion of the reaction is (mol number of reacted diethylene glycol) /
The number of moles of introduced diethylene glycol is defined as (the number of moles of 2-p-dioxanone formed) / (the number of moles of reacted diethylene glycol).

[0046]

EXAMPLES The present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples. In the following Examples and Comparative Examples, “the total amount of acid sites where the acid strength (H ₀ ) of the carrier is higher than 1.5” (hereinafter, referred to as “the total amount of acid sites”)
It is simply referred to as a strong acid content. ) And “the maximum particle size of the supported copper” (hereinafter, also simply referred to as the maximum particle size) were measured as follows.

[Method of Measuring the Amount of Strong Acid Point] 1 g of a carrier was charged into 20 ml of dehydrated benzene, and 2 ml of a 0.1% benzene solution of benzeneazodiphenylamine was added thereto and shaken. The surface of the carrier was colored purple. This was titrated with a 0.1 N benzene solution of normal butylamine. The point at which the surface of the carrier changed from purple to yellow was defined as the end point. By dividing the number of equivalents of normal butylamine required to reach the end point by the surface area of the carrier separately determined by the BET method, the "acid strength (H ₀ ) existing per unit surface area of the carrier"
Is greater than 1.5. "

[Method of Measuring Maximum Diameter] The maximum diameter of copper on the catalyst carrier was determined by a field emission scanning electron microscope (FE-
(SEM). For each catalyst, JEOL
Observation was performed using JSM-6400F. First, 10
Observe the entire view of the sample stage from 0x to 500x,
The presence or absence of copper aggregates of 5 μm or more was confirmed. 5 at this magnification
After confirming that no aggregates of
Observation was carried out at 20,000 to 20,000 magnifications at arbitrary 20 visual fields, and the maximum particle diameter was defined as the maximum diameter of the supported copper.

Example 1 The amount of strong acid sites was 0.1 × 10 ⁻⁷ eq / m ² and the surface area was 450.
Spherical silica 32.4 having m ² / g and an average pore diameter of 6 nm
g (60 ml) was immersed in an aqueous solution of copper (II) nitrate trihydrate dissolved in 26 ml of distilled water, and dried at 80 ° C.
The obtained precursor was mixed with 26 ml of 28% aqueous ammonia and dried again at 80 ° C. This was calcined in an electric furnace at 400 ° C. for 2 hours in an air flow to prepare an unreduced catalyst having a supported amount of 8.0% by weight in terms of copper.

12 ml of this catalyst was charged into a glass reaction tube having an inner diameter of 20 mm, and a gas in which nitrogen and hydrogen were mixed at a volume ratio of 5: 1 at a volume ratio of 300 ml / min. , And the temperature was raised to 300 ° C. to perform a reduction treatment. Thereafter, diethylene glycol was added to the nitrogen / hydrogen mixed gas at 0.4 ml / min. (LHSV = 2.
0h ^{- 1} , diethylene glycol: hydrogen molar ratio = 1: 0.
5) The reaction was performed. Ten minutes after the start of the reaction, the liquid discharged from the lower part of the reaction tube was collected and analyzed by gas chromatography. As a result, the initial conversion of diethylene glycol was 100%, and the initial selectivity of 2-p-dioxanone was 99%. %Met. Most of the by-products were dioxene. Further, even if the reaction was continuously performed for a long time, the conversion was hardly reduced, and the conversion after 100 hours of continuous operation was 99% and the selectivity was 99%.

After the reaction, the catalyst inside the reaction tube was taken out and the surface of the catalyst was observed with a scanning electron microscope. As a result, almost no copper was deposited on the surface of the catalyst, and the maximum diameter of the copper particles observed in a trace amount was 0.1 mm. 3 μm or less, indicating that the finely dispersed state was maintained. FIG. 1 shows a surface photograph of this catalyst by SEM.

[0052] Example as 2 carrier, the amount of strong acid sites is 1.67 × 10 ^{over 7} eq / m ^2,
A catalyst was prepared in the same manner as in Example 1 except that silica alumina (alumina content: 5%) having a surface area of 523 m ² / g was used, and a synthesis reaction of 2-p-dioxanone was performed. The results are shown in Table 1.

[0053]

[Table 1]

Comparative Example 1 A catalyst was prepared in the same manner as in Example 1 except that the treatment with ammonia water was not performed after the preparation of the catalyst precursor.
A synthesis reaction of 2-p-dioxanone was performed. Table 1 shows the results
It was shown to.

After the reaction, the catalyst inside the reaction tube was taken out, and the surface of the catalyst was observed by SEM. As a result, a large amount of copper was deposited on the surface of the catalyst, and many copper particles having a particle size of 0.5 μm or more were observed. FIG. 2 shows a SEM surface photograph of the catalyst. The maximum diameter of the catalyst which did not react after the reduction treatment was also measured, but there was no significant change in the result.

As is clear from the above results, when a catalyst having a maximum diameter of 0.5 μm or less was used, the conversion and selectivity hardly declined with time, whereas the maximum particle diameter decreased. When a catalyst exceeding 0.5 μm is used, 2
-The selectivity of the p-dioxanone synthesis reaction decreases with time.

When the copper coagulation suppression treatment with ammonia was not performed, the precipitation and coagulation of copper on the carrier surface were remarkable, so that the treatment with the coagulation inhibitor was effective in reducing the maximum diameter. It was confirmed that he worked. Comparative Example 2 Strong acid point content of 6.0 × 10 ⁻⁷ eq / m ² and surface area of 200
an alumina which is m ² / g as a carrier, after manufactured Catalyst Precursor Preparation, except that not treated by aqueous ammonia, subjected to catalyst prepared in the same manner as in Example 1, 2-p-
The synthesis reaction of dioxanone and the maximum diameter measurement were performed. The results are shown in Table 1.

Comparative Example 3 The amount of strong acid sites was 6.0 × 10 ⁻⁷ eq / m ² and the surface area was 200.
A catalyst was prepared in the same manner as in Example 1 except that m ² / g of alumina was used as a carrier, and a synthesis reaction of 2-p-dioxanone and measurement of the maximum diameter were performed. The results are shown in Table 1.

[0059] Comparative Example 4 strong acid sites amounts 2.49 × 10 ^{over 7} eq / m ^2, the surface area is 57
Except for using 5 m ² / g of alumina as a carrier,
The catalyst was prepared in the same manner as in Example 1, and the synthesis reaction of 2-p-dioxanone and the measurement of the maximum diameter were performed. The results are shown in Table 1.

As is clear from the results of Comparative Examples 2 to 4,
2.0 × 10 strong acid sites^{ー 7}eq / m ^TwoUse a carrier that exceeds
In the synthesis reaction of 2-p-dioxanone.
The selectivity was significantly reduced, and the production method of Example 1 was higher than that of Example 1.
Conversion rate and high selectivity are compatible, and 2-p-
It is clear that dioxanones can be produced
became.

Comparative Example 5 During the synthesis reaction of 2-p-dioxanone, the flow of hydrogen gas was stopped and the flow rate of nitrogen gas was increased so as to compensate for the decrease in gas flow rate caused by the stoppage of flow of hydrogen gas. The procedure was performed in the same manner as in Example 1 except that the procedure was performed. The results are shown in Table 1.

As is clear from the results, when the flow of hydrogen was stopped, the catalyst was significantly deteriorated when the synthesis reaction of 2-p-dioxanone was performed for a long time, and the production method of Example 1 was higher than that of Example 1. It has been clarified that 2-p-dioxanones can be produced over a long period while achieving both conversion and high selectivity.

Example 3 An experiment was carried out in the same manner as in Example 1 except that 2,2'-oxybis (1-propanol) [hereinafter referred to as dipropylene glycol] was supplied as a reaction raw material. The results are shown in Table 1.

[0064]

According to the production method of the present invention, 2-p-dioxanones can be produced over a long period while achieving both high conversion and high selectivity in the synthesis reaction of 2-p-dioxanones.

Since the catalyst used in the present invention has a small variation in performance due to the difference between production lots, the production method of the present invention has excellent effect reproducibility.

[Brief description of the drawings]

FIG. 1 is an SEM photograph of a catalyst surface treated with an aggregation inhibitor.

FIG. 2 is an SEM photograph of a catalyst surface that has not been treated with an aggregation inhibitor.

Continued on the front page F term (reference) 4C022 JA04 4G069 AA03 AA08 BA02A BA02B BC31A BC31B BD01B CB07 CB19 DA05 FB14 FB30 FC04 4H039 CA42 CH20

Claims (2)

[Claims] 1. A catalyst comprising copper supported on a carrier having an acid strength (H ₀ ) of greater than 1.5 and having a total amount of acid sites of not more than 2 × 10 ^-7 equivalents per square meter and diethylene glycols in the presence of hydrogen. In the method of producing 2-p-dioxanones by contacting the support underneath, the maximum particle size of the supported copper is 0.1.
A catalyst having a size of 5 μm or less is used.
A method for producing p-dioxanones. 2. The method according to claim 1, wherein the carrier is silica.
A method for producing p-dioxanones.