JPH08104662A - Production of ester - Google Patents

Abstract

PURPOSE: To produce an ester having high quality in high yield at a low cost by reacting an acid with an alcohol using a heteropolyacid baked at a specific temperature as a catalyst, thereby suppressing the formation of by-products and reducing the energy cost. CONSTITUTION: The objective ester is produced by reacting (A) an acid such as propionic acid or phthalic acid (anhydride) with (B) an alcohol such as octanol or glycol using (C) a catalyst comprising a heteropolyacid baked at 105-540 deg.C (e.g. 12-tungstophosphoric acid, 12-tungstosilicic acid, 12-tungstoboric acid, 12-tungstogermanic acid, 12-molybrophosphoric acid or 12-molybrosilicic acid) as a catalyst. The reaction is carried out e.g. at 80-150 deg.C and 750mmHg to 2kg/cm<2> pressure for 2-8hr.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a method for producing an ester.

[0002]

2. Description of the Related Art Conventionally, a method for producing an ester by reacting an acid with an alcohol has been widely used industrially. Sulfuric acid, p-toluenesulfonic acid and the like are generally used as a catalyst in the production of the above ester, but these catalysts have problems such as difficulty in separation and recovery and generation of a large amount of by-products. There is.

If an organometallic catalyst is used as a catalyst,
Although it is possible to suppress the production of by-products, there is a problem in that the reaction temperature is high and the energy cost is high, which is economically disadvantageous.

Further, in the esterification reaction using an acid and an alcohol, if a heteropoly acid is used as a catalyst,
Energy costs are low because the reaction proceeds at low temperatures, which is economically advantageous, but the production of by-products cannot be suppressed, yields are reduced, and product quality is adversely affected. There is.

As a method for producing an ester using the above heteropolyacid as a catalyst, for example, Appl. Cat., 7
4 , 191 (1991) describes a method of esterifying an acid with an alcohol using a calcined heteropoly acid as a catalyst, and JP-A-5-301842.
In the publication, a catalyst of at least one salt selected from phosphotungstomolybdic acid, silicotungstomolybdic acid, or cesium salt, rubidium salt, thallium salt, ammonium salt, and potassium salt of phosphorustungstomolybdic acid or silicotungstomolybdic acid is disclosed. In the presence of
A method for producing a lower fatty acid ester by reacting a lower fatty acid with a lower olefin has been proposed.

However, neither of the above two methods has a description regarding the production of by-products, and it is unclear whether or not the problems regarding the production of by-products have been solved.
Further, there is no clear description about the influence of the esterification reaction temperature and the catalyst calcination temperature on the production of by-products.

[0007]

In order to solve the above-mentioned conventional problems, the present invention is an ester of an acid and an alcohol, which can suppress the formation of by-products and has a low energy cost and is economically advantageous. It aims at providing the manufacturing method of.

[0008]

The method for producing an ester according to the present invention is characterized in that an acid and an alcohol are reacted with a heteropoly acid calcined in a temperature range of 105 to 450 ° C. as a catalyst, whereby the above The purpose is achieved.

The heteropolyacid used as a catalyst in the method for producing an ester according to the present invention is an acid produced by two or more metals among polyacids formed by condensation of an inorganic acid, and generally, It is formed by using one metal as a central atom and coordinating a polyacid group of another metal.

Specific examples of the above-mentioned heteropolyacid include, but are not limited to, 12-tungstophosphoric acid,
12-tungstosilicic acid, 12-tungstoboric acid, 1
2-tungstogermanic acid, 12-molybdophosphoric acid, 1
2-molybdosilicic acid and the like can be mentioned, and one or more of these are preferably used.

In the method for producing an ester according to the present invention, it is necessary that the above heteropolyacid is calcined in the temperature range of 105 to 450 ° C, preferably the esterification reaction temperature of 450 ° C.

When the firing temperature of the heteropolyacid is less than 105 ° C., the water content in the heteropolyacid is insufficiently removed, and when the acid and the alcohol are esterified, a by-product is often produced. When the firing temperature of the heteropolyacid exceeds 450 ° C., the heteropolyacid causes thermal deterioration,
It is considered that the sustainability of the catalytic function is shortened and the amount of by-products produced during the esterification reaction is increased.

The method for firing the above-mentioned heteropolyacid is not particularly limited, but is in the air or in an inert gas atmosphere such as nitrogen gas under atmospheric pressure or reduced pressure in the temperature range of 105 to 450 ° C., for example, The firing may be performed for about 5 to 20 hours.

The method for producing an ester according to the present invention is carried out by using an esterification reaction between an acid and an alcohol, using the heteropolyacid calcined in the temperature range of 105 to 450 ° C. as a catalyst.

The type of the above-mentioned acid is not particularly limited, but examples thereof include monobasic acids such as acetic acid, propionic acid and butyric acid, and diacids such as phthalic acid, adipic acid, sebacic acid, oleic acid and fumaric acid. Examples thereof include polybasic acids such as basic acids, trimellitic acid, and pyromellitic acid, and carboxylic acid anhydrides such as phthalic anhydride, and one or more of these are preferably used.

The type of the above alcohol is not particularly limited, but for example, butanol, hexanol, heptanol, n-octanol, 2-ethylhexanol, nonyl alcohol, lauryl alcohol, butyl lauryl alcohol, butyl benzyl. Examples thereof include alcohols, cresyl alcohol, glycols, polyhydric alcohols such as pentaerythritol, and the like, and one or more of these are preferably used.

The molar ratio of the acid and alcohol charged in the esterification reaction is not particularly limited, but for example, in the esterification reaction of a divalent acid and a monovalent alcohol, the alcohol / acid is used. = 2 to 3 (molar ratio), and the charged molar ratio at the time of the usual esterification reaction may be sufficient.

The amount of the heteropolyacid used as a catalyst for the esterification reaction and calcined in the temperature range of 105 to 450 ° C. is not particularly limited, but 5 to 5 mol of the heteropolyacid per 1 mol of the acid. It is preferably about 30 parts by weight.

Further, the conditions for the esterification reaction of the above acid and alcohol are not particularly limited, but the reaction temperature is about 80 to 150 ° C., the reaction pressure is −750 mmHg.
It may be carried out under normal esterification reaction conditions of about ² kg / cm ² and a reaction time of about 2 to 8 hours.

[0020]

In the method for producing an ester according to the present invention, the acid and the alcohol are reacted with the heteropoly acid calcined in the temperature range of 105 to 450 ° C. as a catalyst, so that the production of by-products can be suppressed and the temperature is relatively low. The reaction proceeds, which is economically advantageous with low energy cost.

[0021]

EXAMPLES In order to explain the present invention in more detail, examples will be given below.

(Example 1)

(A ) Preparation of Heteropoly Acid 12-Tungstophosphoric acid (H ₃ P ) synthesized by a conventional method
_{W 12 O 40 · nH 2 O} ) 10.55g was placed in a petri dish,
Baking was performed at 110 ° C. for 15 hours in a vacuum dryer to obtain 9.20 g of dark beige-colored baked 12-tungstophosphoric acid.

( B) Production of ester In a reactor equipped with a Gene Stark oil / water separator, 149.5 g (1.15 mol) of octanol and 7 parts of phthalic anhydride were used.
4.0 g (0.50 mol) was charged and the temperature was raised to 110 ° C. to dissolve phthalic anhydride. Then, 6 g of 12-tungstophosphoric acid obtained above, which was calcined at 110 ° C.
After adding, the degree of pressure reduction was adjusted so that the mixture was slowly refluxed, and the esterification reaction was carried out at a set temperature of 110 ° C. with stirring.

( C) Evaluation During the above esterification reaction, 2 g of a sample (reaction liquid) was sampled at predetermined intervals, the weight was accurately weighed, and then 0.1 N
-KOH solution (solvent is ethanol / water = 1 / by weight ratio)
The titration was performed in 1) to determine the acid value (mg-KOH / g) and the conversion rate to the ester (mol%). In addition, the weight% of the amount of by-products with respect to the amount of alcohol in the sample was determined by using gas chromatography. The evaluation results are shown in Table 1.

(Example 2)

In the production of ester, the charged amount of octanol was 74.77 g (0.575 mol) and the charged amount of phthalic anhydride was 37.2 g (0.25 mol), and the temperature was 110 ° C. obtained in Example 1. The esterification reaction was carried out in the same manner as in Example 1 except that the amount of the 12-tungstophosphoric acid calcined in step 3 was changed to 3 g and the temperature for the esterification reaction was set to 100 ° C.

(Comparative Example 1)

In preparing the heteropolyacid, 10.20 g of 12-tungstophosphoric acid synthesized in Example 1 was put in a petri dish and baked in a vacuum dryer at 100 ° C. for 15 hours.
Dark beige calcined 12-tungstophosphoric acid 9.
52 g were obtained.

In the production of the ester, the amount of octanol charged was 74.77 g (0.575 mol), and the amount of anhydrous phthalate charged was 37.2 g (0.25 mol), and the calcination was carried out at 100 ° C. The esterification reaction was performed in the same manner as in Example 1 except that the amount of 12-tungstophosphoric acid added was 3 g.

(Comparative Example 2)

In adjusting the heteropolyacid, 10.60 g of 12-tungstophosphoric acid synthesized in Example 1 was put in a petri dish and calcined in a vacuum dryer at 500 ° C. for 15 hours.
Dark beige calcined 12-tungstophosphoric acid 9.
01 g was obtained.

In the production of the ester, the charged amount of octanol was 74.77 g (0.575 mol), and the charged amount of phthalic anhydride was 37.2 g (0.25 mol), and the calcination was carried out at 500 ° C. The esterification reaction was performed in the same manner as in Example 1 except that the added amount of 12-tungstophosphoric acid was 3 g.

During the esterification reaction of Example 2 and Comparative Examples 1 and 2, the acid value, the conversion rate into ester and the amount of by-products were determined in the same manner as in Example 1. The results are shown in Table 1.

[0035]

[Table 1]

As shown in Table 1, the method for producing the ester of Example 1 and Example 2 using the heteropoly acid calcined at 110 ° C. as a catalyst showed a sufficient reaction rate and
There is no formation of by-products.

On the other hand, as shown in Table 1, 1
The method for producing the ester of Comparative Example 1 using the heteropolyacid calcined at 00 ° C. as a catalyst and the method of producing the ester of Comparative Example 2 using the heteropolyacid calcined at 500 ° C. as a catalyst are both by-products. Is often generated.

[0038]

Industrial Applicability As described above, according to the method for producing an ester of the present invention, a high-quality ester is obtained from an acid and an alcohol without producing a by-product, which is economically advantageous in a high yield. Can be obtained by the method.

Claims (1)

[Claims] 1. A method for producing an ester, which comprises reacting an acid with an alcohol using a heteropoly acid calcined in a temperature range of 105 to 450 ° C. as a catalyst.