JP2001062308A - Solid acid catalyst - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain higher activity and durability by using a catalyst composition having a structure removing a hydrogen atom from at least one OH group in an inorganic phosphoric acid and a structure removing a hydrogen atom from at least one OH group in an organic phosphoric acid represented by a specific formula, and containing a specific metal atom such as aluminum. SOLUTION: This solid acid catalyst has structures (A) and (B), and a metal atom (C); (A): a structure obtained by removing a hydrogen atom from at least one OH group in an inorganic phosphoric acid; (B): a structure obtained by removing a hydrogen atom from at least one OH group in an organic phosphoric acid represented by formula I or formula II (wherein -R1 and -R2 are independently selected from -R, -OR, -OH and -H, and at least one of -R1 and -R2 is -R or -OR, provided that -R is a 1-22C organic group.); and (C): one or more metal atoms selected from among aluminum, gallium and iron. As a result, the catalyst exhibits higher activity and durability.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a solid acid catalyst and a method for producing an ester, ketal or acetal using the solid acid catalyst.

[0002]

2. Description of the Related Art A solid acid catalyst has advantages such as easy operation of isolating a product after completion of a reaction, and its use in various organic reactions has been studied. ing. For example, zeolite (JP-A-61-200943), IV
Group silicates (EP0623581A2), hydrous zirconium oxide (JP-B 4-28250) and the like are used for the production of esters, organic solid catalysts such as ion exchange resins, hydrous zirconium oxide (JP-A-63-146838), mordenite (JP
Inorganic solid catalysts such as 60-188338) are known for producing acetal or ketal.

[0003] When these solid catalysts are used in a liquid phase reaction, the activity at low temperatures is insufficient, and the activity or the durability of the catalyst strength is satisfied due to the elution of the catalyst components into the liquid phase. Can not.

[0004] It is an object of the present invention to provide a solid acid catalyst which exhibits high activity against various organic reactions and exhibits high durability.

[0005]

The present invention has the following structure:
(A), a solid acid catalyst having a structure (B) and a metal atom (C), and a method for producing an ester and a ketal or an acetal using the solid acid catalyst. Structure (A); a structure in which a hydrogen atom is removed from at least one of the OH groups of the inorganic phosphoric acid. Structure (B); a structure of the OH group of the organic phosphoric acid represented by the general formula (1) or (2). Structure with at least one hydrogen atom removed

[0006]

Embedded image

[Wherein -R ¹ and -R ² each represent-
R, -OR, -OH, -H, -R ¹ and -R
^At least one of ² is -R or -OR. However,
-R is an organic group having 1 to 22 carbon atoms. Metal atom (C); one or more metal atoms selected from aluminum, gallium, and iron

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION Structure (A) in the solid acid catalyst of the present invention
Examples of the inorganic phosphoric acid include orthophosphoric acid, metaphosphoric acid, and condensed phosphoric acid such as pyrophosphoric acid. Orthophosphoric acid is preferable from the viewpoint of performance.

In the structure (B), as the organic phosphoric acid represented by the general formula (1) or (2), phosphonic acid, phosphonic acid monoester, phosphinic acid, phosphoric acid monoester, phosphoric diester, phosphorous acid Acid monoester, phosphite diester and the like, and a mixture thereof may be used.
Preferably it is a phosphonic acid.

As the organic group -R in the organic phosphoric acid, methyl, ethyl, n-propyl, iso-propyl, n-butyl, is
Alkyl groups such as o-butyl, tert-butyl, n-hexyl, 2-ethylhexyl, octyl, dodecyl, octadecyl, etc., and aryl groups such as phenyl and 3-methylphenyl are preferable. , Carbonyl group, alkoxycarbonyl group, carboxylic acid group,
A group to which a halogen group such as a chloro group, a phosphonic acid group, a sulfonic acid group, or the like is bonded may also be used.

As the metal atom (C), aluminum is preferred from the viewpoint of performance and / or cost. For the purpose of improving selectivity and other performance, aluminum, gallium,
It may have a small amount of metal atoms other than iron.

Structures (A) and (B) in the solid acid catalyst of the present invention
It is preferable that the molar ratio x of the organic phosphoric acid represented by the following formula (3) is 0.01 to 0.99 from the viewpoint of performance. Here, [Pinorg] indicates the number of moles of phosphorus atoms contained in the structure (A), and [Porg] indicates the number of moles of phosphorus atoms contained in the structure (B).

X = [Porg] / ([Pinorg] + [Porg]) (3) Further, the ratio x has a more preferable ratio depending on the reaction to be used. In the production of the ester, x is 0.01 to 0.7. Is preferable, and 0.01 to 0.5 is more preferable. For the production of ketal or acetal, x is preferably 0.05 to 0.99, more preferably 0.1 to 0.8.

The value Y represented by the following equation (4) is 0.15
Preferably it is ~ 2.0.

Y = [Metal] / ([Pinorg] + [Porg]) (4) Here, [Metal] indicates the number of metal atoms (C) in the catalyst.

All of the metal atoms (C) contained in the catalyst are
It does not necessarily have to be bonded to the structure (A) or the structure (B), and a part of the metal atom (C) may exist in the form of a metal oxide or a metal hydroxide.

As a method for preparing the solid acid catalyst of the present invention, a precipitation method, a method of impregnating a metal oxide or a hydroxide with inorganic phosphoric acid and an organic phosphoric acid, and a method of preparing an inorganic aluminum phosphate gel from an inorganic aluminum phosphate gel. A method of substituting an organic phosphate group or the like is used, and a precipitation method is preferable. In the precipitation method, an aqueous solution of a water-soluble aluminum salt and an inorganic phosphoric acid or an organic phosphoric acid (S) is mixed with an alkali (T) such as an aqueous ammonia solution, an aqueous sodium carbonate solution, or an aqueous caustic soda solution to adjust the pH. A precipitate of the solid acid catalyst is obtained. The order of adding the aqueous solution (S) and the alkali (T) is not limited.
When the organic phosphoric acid has poor water solubility, an aqueous solution (S) may be prepared by appropriately adding a solvent such as methanol or acetone. The obtained precipitate is dried and, if necessary, further baked. At this time, firing at a high temperature may cause loss of the organic groups in the structure derived from the organic phosphoric acid, and firing at 600 ° C or lower is preferable, and firing at 500 ° C or lower is more preferable.

When preparing the catalyst of the present invention, a supported catalyst can be obtained by coexisting a carrier having a high surface area. As a carrier, silica, alumina, silica alumina,
Titania, zirconia, activated carbon and the like can be used. If the carrier is used in excess, the content of the active ingredient is reduced and the activity is reduced. Therefore, the proportion of the carrier in the catalyst is preferably 90% by weight or less.

The form of the catalyst can be used by dispersing it in the raw material as it is in the form of powder, or it can be formed into an appropriate particle size or shape and filled in a reaction tower to perform a continuous reaction.

It is essential that the solid acid catalyst of the present invention has the structure (A) and the structure (B) at the same time when used in the reaction. However, it is not necessary to have all the inorganic phosphate groups and organic phosphate groups used in the preparation.

The solid acid catalyst of the present invention can be used for various catalytic reactions, for example, transesterification, esterification,
Acetalization from aldehyde and alcohol or ketalization from ketone and alcohol, aldol condensation reaction, amidation, amination, synthesis of olefin or ether by dehydration reaction of alcohol, hydration to olefin or addition reaction of alcohol, isomerization Reaction, alkylation or acylation of an aromatic ring, and the like.

As for the reaction conditions in the above-mentioned various reactions, for example, the reaction phase (gas phase or liquid phase) is selected under the optimum conditions depending on the type of the reaction, but the solid acid catalyst of the present invention has high activity even under mild conditions. Therefore, it is preferable to use not only in the gas phase but also in a liquid phase condition where it is difficult to exhibit high activity with a conventional solid catalyst. Further, for example, the reaction pressure is selected under optimum conditions depending on the type of the reaction, and the reaction may be performed under increased pressure, or may be performed under atmospheric pressure or reduced pressure. Further, for example, the reaction temperature is a temperature at which the organic group in the structure (B) does not disappear, for example, it is preferably used at 600 ° C. or lower in the presence of oxygen, and more preferably at 500 ° C. or lower.

The solid acid catalyst of the present invention shows a very high activity and good selectivity for a transesterification reaction or an esterification reaction, and can maintain its activity and selectivity for a long period of time. As a result, a high yield and high purity ester can be obtained over a long period of time with a short reaction time.

In the transesterification or esterification reaction, the starting ester or starting carboxylic acid (a) is mixed with the starting alcohol.
(b) is mixed and brought into contact with the solid acid catalyst under the reaction conditions.

Of the raw material ester or raw material carboxylic acid (a), the raw material ester is, for example, an aliphatic carboxylic acid or aromatic carboxylic acid having a linear or branched chain having 1 to 22 carbon atoms or a mixture thereof, Esters or partial esters with monohydric alcohols or polyhydric alcohols having 1 to 22 linear or branched chains are used. Specifically, acetic acid, butyric acid, caproic acid, caprylic acid, capric acid, lauric acid, myristic acid, palmitic acid, oleic acid, stearic acid, carboxylic acid such as benzoic acid or a mixture thereof and methanol, Ethanol, propanol, butanol, octanol,
Esters composed of monohydric aliphatic alcohols such as stearyl alcohol, monohydric aromatic alcohols such as phenol, and polyhydric alcohols such as ethylene glycol, propylene glycol, glycerin, pentaerythritol, and sorbitol; monoglyceride, diglyceride, triglyceride, and coconut Preferred are natural vegetable oils such as oil, palm oil and palm kernel oil, and animal oils such as tallow and lard. As the raw material carboxylic acid, the above-mentioned aliphatic carboxylic acid or aromatic carboxylic acid having a straight or branched chain having 1 to 22 carbon atoms or a mixture thereof is used.

As the raw material alcohol (b), the above-mentioned linear or branched monohydric alcohol or polyhydric alcohol having 1 to 22 carbon atoms is used.

The esterification method includes, for example, a method in which a raw material ester or a raw material carboxylic acid (a) and a raw material alcohol (b) are continuously supplied to a reaction tower filled with a solid acid catalyst, and a batch type in a reaction tank. Raw ester or raw carboxylic acid (a)
And the starting alcohol (b) is brought into contact with a solid acid catalyst to carry out the reaction. At that time, the treatment after the reaction is only filtration, and a neutralization step and a catalyst removal step which are necessary in the case of a generally used homogeneous catalyst can be omitted. In addition, recovery of unreacted raw materials becomes easy.

Preferred conditions for the reaction pressure and temperature can be selected according to the desired reaction. As for the reaction temperature, it is preferable to carry out the reaction at a lower temperature in consideration of a side reaction. The solid acid catalyst of the present invention exhibits higher esterification reaction activity even at low temperature conditions than the conventional solid acid catalyst, so that the target ester can be obtained with a high selectivity.

The solid acid catalyst of the present invention exhibits very high activity and good selectivity for the acetalization or ketalization reaction of a ketone or aldehyde (c) with an alcohol (d). Its activity and selectivity can be maintained for a long time. As a result, acetal or ketal with high yield and high purity can be obtained for a long period of time in a short reaction time.

The ketone or aldehyde (c) has 1 to 1 carbon atoms.
An aliphatic ketone or aldehyde having 22 straight or branched chains, an aromatic ketone or aldehyde, or the like is used.
More specifically, acetone, methyl ethyl ketone, 3-
Pentanone, 2-pentanone, di-n-hexyl ketone,
Examples include cyclohexanone, acetophenone, acetaldehyde, propionaldehyde, n-hexanal, n-dodecanal, benzaldehyde and the like.

As the alcohol (d), the same alcohol as the starting alcohol (b) exemplified in the above esterification reaction is used.

[0032] The ketalization or acetalization method is, for example, a ketone or aldehyde (c) and an alcohol (d).
Is continuously supplied to a reaction tower filled with a catalyst,
Alternatively, there is a method of performing the reaction batchwise in a reaction tank.
At that time, the reaction rate or the reaction equilibrium can be made advantageous by distilling off the generated water using a suitable azeotropic solvent such as benzene or heptane.

If the solid acid catalyst of the present invention is used, the treatment after the reaction can be carried out only by filtration. Therefore, the neutralization step necessary for a generally used homogeneous catalyst such as paratoluenesulfonic acid or mineral acid is required. Can be omitted. Also, during distillation,
No side reaction or the like due to the presence of the salt occurs, the yield at the time of purification can be increased, and the unreacted raw material can be easily recovered.

[0034]

EXAMPLES Example 1-1 (Preparation of catalyst) 14.2 g of phenylphosphonic acid and 27.7% of 85% orthophosphoric acid
g, 112.5 g of aluminum nitrate (nonahydrate) in 1000 parts of water
g and 80 g of methanol. At room temperature, an aqueous ammonia solution was added dropwise to the mixed solution to raise the pH to 5. On the way, a gel-like white precipitate was formed. The precipitate was filtered, washed with water, and dried at 110 ° C. for 15 hours. The powder was pulverized to a size of 60 mesh or less and calcined at 250 ° C. for 3 hours to obtain a solid acid catalyst.

The results of analyzing the composition of the obtained catalyst are shown in Table 1.
Shown in The composition analysis was performed using an ICP analyzer (ICPS1000III manufactured by Shimadzu Corporation) for metal and P, and using a CHN elemental analyzer (2400-2 manufactured by PerkinElmer) for C. In addition, P-NMR of the obtained catalyst (UNITY IN manufactured by Varian)
When OVA 300 was used, the results shown in FIG. 1 were obtained. The peak derived from P in the structure derived from orthophosphoric acid (−29.2 Hz) and the P in the structure derived from phenylphosphonic acid were analyzed. It was confirmed that two peaks (−5.2 Hz) derived from the above coexisted. The identification of each peak was carried out by comparing with the peaks of aluminum phenylphosphonate prepared in Comparative Example 1-1 and aluminum phosphate prepared in Comparative Example 1-2, and further, the literature values
(Inorg. Chem., 37 (1998), 4168 etc.).

[Pinorg] and [Porg] present in the catalyst were calculated based on the results of the composition analysis of C and P, and the molar ratio x of the organic phosphoric acid represented by the above formula (3) was determined. Table 1 shows the results.

Example 1-2 (Catalyst preparation) A solid acid catalyst was obtained in the same manner as in Example 1-1 except that the types and amounts of raw materials and the preparation conditions were changed as shown in Table 1. Table 1 shows the composition analysis value and the organic phosphoric acid molar ratio x of the obtained catalyst.

When the P-NMR of the obtained catalyst was analyzed, the result shown in FIG. 2 was obtained. The peak derived from P in the structure derived from orthophosphoric acid (−29.8 Hz),
It was confirmed that a peak (-5.3 Hz) derived from P in the structure derived from phenylphosphonic acid coexisted.

Examples 1-3 to 1-8 (Preparation of catalyst) A solid acid catalyst was prepared in the same manner as in Example 1-1 except that the types and amounts of raw materials and preparation conditions were changed as shown in Table 1. I got Table 1 shows the composition analysis value and the organic phosphoric acid molar ratio x of the obtained catalyst.

Comparative Example 1-1 (Preparation of Catalyst) 47.4 g of phenylphosphonic acid and 75.0 g of aluminum nitrate (9 hydrate) were dissolved in 800 g of water and 160 g of methanol. At room temperature, an aqueous ammonia solution was dropped into the mixed solution to raise the pH to 4. On the way, a gel-like white precipitate was formed. The precipitate is filtered, washed with water, and
For 15 hours. The catalyst was obtained by pulverizing to a size of 60 mesh or less and calcining at 250 ° C. for 3 hours.

The results of analyzing the composition of the obtained catalyst are shown in Table 1.
Shown in In addition, P-NMR analysis of the obtained catalyst gave the results shown in FIG. 3, and it was confirmed that a peak derived from a structure derived from phenylphosphonic acid was present at -9.5 Hz.

Comparative Example 1-2 (Preparation of Catalyst) 563 g of 85% orthophosphoric acid and 173 g of aluminum nitrate (9-hydrate) were dissolved in 5000 g of water. At room temperature, an aqueous ammonia solution was added dropwise to the mixed solution to adjust the pH to 7.
Up. On the way, a gel-like white precipitate was formed.
The precipitate was filtered, washed with water, and sufficiently dried at 110 ° C. The catalyst was obtained by pulverizing to a size of 60 mesh or less and calcining at 400 ° C. for 3 hours.

The results of analyzing the composition of the obtained catalyst are shown in Table 1.
Shown in When the obtained catalyst was analyzed by P-NMR, the results shown in FIG. 4 were obtained, and it was confirmed that the peak derived from P in the structure derived from orthophosphoric acid was present at −28.4 Hz. .

[0044]

[Table 1]

Examples 2-1 to 2-6, Comparative Examples 2-1 and 2
-4 (esterification reaction) In an autoclave, palm kernel oil (triglyceride) 200
g, methanol 55.8 g, Example 1 as the catalyst of the present invention
-1 and the solid acid catalyst prepared in 1-4 to 1-8, the catalyst prepared in Comparative Examples 1-1 and 1-2 as a comparative catalyst, and zirconium hydroxide (manufactured by the first rare element) in the air at 300 10 g of hydrous zirconium hydroxide and mordenite (manufactured by Tosoh Corporation) obtained by calcining at 2 ° C. for 2 hours were charged. Reaction temperature 200 ℃
After a suspension reaction under sealed conditions for 5 hours, the catalyst was filtered off, the composition of the reaction-terminated liquid was analyzed by gas chromatography to determine the ester yield at the 5th hour, and the following formula (4) The reaction rate represented by was determined. Table 2 shows the results. The ester yield at the time of reaction equilibrium was 81.7%.

Reaction rate [1 / hr] = [ln ((EV ₀ −EVe) / (EV _5h −EVe))] / 5 (4) Here, EV ₀ is the ester value of the raw material triglyceride (KOHm
g / g), EVe is the equilibrium ester value (KOHmg / g), EV _5h the ester value glycerides remaining in the reaction liquid of the reaction 5 hours (KOHmg / g).

[0047]

[Table 2]

Examples 3-1 to 3-2, Comparative Example 3-1 (Esterification Reaction) The solid acid catalyst prepared in Examples 1-1 and 1-5 as a catalyst of the present invention, and a comparative example as a comparative catalyst Using the catalyst prepared in 1-2, these were extruded into noodles, filled in a reaction tower, and a fixed bed continuous reaction of palm kernel oil (triglyceride) and methanol was performed. The reaction conditions are temperature 17
0 ° C, methanol / triglyceride molar ratio 10 [mol / mo
l], LHSV 0.2 [1 / hr]. Table 3 shows the ester yield and the reaction rate represented by the following formula (5).
Note that the equilibrium ester yield is 95.5%.

Reaction rate = ln ((EV inlet−EVe) / (EV outlet−EVe)) (5) Here, the EV inlet is the ester value of the raw material triglyceride (KO
Hmg / g) and EVe are the equilibrium ester value (KOHmg / g), and the EV outlet is the ester value (KOHmg / g) of glyceride remaining in the reaction solution at the outlet of the reaction tower.

Comparative Example 3-2 (Esterification reaction) Titanosilicate [Ti / Si = 1 / 9.2, prepared by alkoxide method (Akushi Ueno et al., IPC, P303,
The catalyst extruded into noodle shape was packed in a reaction tower, and a fixed bed continuous reaction between palm kernel oil (triglyceride) and methanol was carried out. The reaction was carried out at a temperature of 200 ° C., a methanol / triglyceride molar ratio of 60 [mol / mol], and an LHSV of 0.2 [1 / hr], which are more advantageous for the progress of the reaction than in Example 3-1. Table 3 shows the ester yield and the reaction rate represented by the above formula (5).

[0051]

[Table 3]

Examples 4-1 and 4-2 (Esterification reaction) Using the solid acid catalyst prepared in Example 1-5, Example 3-
Under the same conditions as in Example 2, continuous operation was performed for a long period of time at the flow rate shown in Table 4 (the ratio of the weight of the raw material triglyceride that had passed in the period up to the weight of the catalyst charged in the reaction tower). Table 4 shows the results. As is evident from Table 4, a high triglyceride conversion (ester yield) was maintained.

[0053]

[Table 4]

Example 5-1 (Ketalization reaction) In a 200 ml flask, 32.4 g of methyl ethyl ketone, 27.6 g of glycerin, 13.2 g of heptane, and a catalyst of Example 1 were used.
3.75 g of the solid acid catalyst prepared in -1 was added. The temperature was raised using an oil bath, and heptane and water began to distill at about 100 ° C. Thereafter, the temperature was gradually increased while keeping the distillate amount constant. The progress of the reaction was followed by the amount of distilled water. However, about 20% of methyl ethyl ketone was dissolved in the distillate. The reaction rate was compared with the distillation rate of the distillate.
Table 5 shows the results. The time required for the amount of distilled water to reach 6 ml indicates that the shorter the time, the higher the reaction activity. The reaction was completed in 5 hours, and the amount of distillate at that time was 6.2 ml.
Met.

Thereafter, the catalyst was removed by filtration, and a glycerin ketal was obtained by distillation. 93.7 yield of ketal
%, Selectivity was 98.4%.

Examples 5-2 and 5-3 (Ketalization reaction) Except that the solid acid catalyst prepared in Examples 1-2 and 1-3 was used as a catalyst, the same method as in Example 5-1 was used. The reaction was performed. Table 5 shows a comparison result of the distillation speed of the distillate.

Comparative Example 5-1 (Ketalization Reaction) A reaction was carried out in the same manner as in Example 5-1 except that the catalyst prepared in Comparative Example 1-1 was used as a catalyst. Table 5 shows a comparison result of the distillation speed of the distillate. Thereafter, the catalyst was removed by filtration, and the ketal of glycerin was obtained by distillation.
The ketal yield was 89.2% and the selectivity was 97.6%.

Comparative Example 5-2 (Ketalization reaction) A reaction was carried out in the same manner as in Example 5-1 except that the catalyst prepared in Comparative Example 1-2 was used as a catalyst. Table 5 shows a comparison result of the distillation speed of the distillate. After 5.0 hours of reaction,
The catalyst was removed by filtration, and the ketal of glycerin was obtained by distillation. The ketal yield was 40.5%.

Comparative Example 5-3 (Ketalization reaction) The reaction was carried out in the same manner as in Example 5-1 except that the same hydrous zirconium hydroxide as used in Comparative Example 2-3 was used as the catalyst. Table 5 shows a comparison result of the distillation speed of the distillate.

[0060]

[Table 5]

Example 6-1 (Esterification reaction) Using the solid acid catalyst prepared in Example 1-5 as a catalyst of the present invention, these were extruded into noodles, filled into a reaction tower, and charged with a fatty acid and methanol. And a fixed bed continuous reaction was performed. The reaction conditions were as follows: temperature 200 ° C., system pressure 1.0 MPa, methanol / fatty acid molar ratio 3 [mol / mol], LHSV 0.5
[1 / hr]. As the fatty acid, a mixture of lauric acid and myristic acid (acid value 270 KOHmg / g) was used.
By removing methanol and water from the liquid discharged from the reaction tower, fatty acid methyl ester was obtained in a yield of 90.5%. Subsequently, the resulting 90.5% crude methyl ester was
Temperature 200 ° C, system pressure 1.0MPa, methanol / (fatty acid and methyl ester) molar ratio 3 [mol / mol], LHSV
The reaction was performed under the condition of 1 [1 / hr]. By removing methanol and water from the liquid discharged from the reaction tower, 99.7
The fatty acid methyl ester was obtained in a% yield.

[0062]

Since the solid acid catalyst of the present invention has an organic group on the solid surface, it has a high affinity between the organic reaction substrate and the catalytic surface active site, and is highly active.

This catalyst can be used for various catalytic reactions. In particular, for the production of esters by esterification or transesterification, and the production of ketals or acetals by ketalization or acetalization, the product can be easily separated from the catalyst. Can be obtained at high efficiency and high selectivity.

[Brief description of the drawings]

FIG. 1 is a P-NMR spectrum of a catalyst obtained in Example 1-1.

FIG. 2 is a P-NMR spectrum of the catalyst obtained in Example 1-2.

FIG. 3 is a P-NMR spectrum of the catalyst obtained in Comparative Example 1-1.

FIG. 4 is a P-NMR spectrum of the catalyst obtained in Comparative Example 1-2.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) C07C 67/03 C07C 67/03 67/08 67/08 69/26 69/26 // C07B 61/00 300 C07B 61/00 300 (72) Inventor Noriaki Fukuoka 1334 Minato 1334 Minato, Wakayama-shi, Wakayama Pref. (72) Inventor Yasuyuki Hattori 1334 Minato 1 Minato, Wakayama-shi, Wakayama Pref.

Claims (5)

[Claims] 1. The following structure (A), structure (B) and metal atom (C)
A solid acid catalyst having Structure (A); a structure in which a hydrogen atom is removed from at least one of the OH groups of the inorganic phosphoric acid. Structure (B); a structure of the OH group of the organic phosphoric acid represented by the general formula (1) or (2). Structure with at least one hydrogen atom removed [Wherein -R ¹ and -R ² are each -R, -OR,
-OH, selected from -H, at least one of -R ¹ and -R ^2, it is -R or -OR. Here, -R is an organic group having 1 to 22 carbon atoms. ] Metal atom (C); one or more metal atoms selected from aluminum, gallium and iron 2. The solid acid catalyst according to claim 1, wherein the structure (A) is a structure derived from orthophosphoric acid. 3. The solid acid catalyst according to claim 1, wherein the structure (B) is a structure derived from phosphonic acid. 4. A process for producing an ester from the starting ester or starting carboxylic acid (a) and the starting alcohol (b) using the catalyst according to claim 1. 5. A ketone or aldehyde (c) and an alcohol, using the catalyst according to any one of claims 1 to 3.
(d) A method for producing a ketal or acetal from which a ketal or acetal is produced.