JPH07188086A - Production of dipentaerythritol - Google Patents

Abstract

PURPOSE:To provide a new producing method capable of efficiently producing dipentaerythritol from an industrially inexpensively available raw material. CONSTITUTION:Pentrerythritol is reacted with ureas in the presence of a titanium catalyst to produce the objective dipentaerythritol.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a novel method for producing dipentaerythritol.

[0002]

2. Description of the Related Art Dipentaerythritol is useful as a raw material for polyester, polyether, polyurethane, alkyd resin, lubricating oil and the like. Dipentaerythritol is a by-product during the synthetic reaction of pentaerythritol, that is, when reacting formaldehyde and acetaldehyde in the presence of alkali to produce pentaerythritol, and is obtained by separating and purifying it. This is a general industrial production method (JP-A-57-139028).

Further, as a method for improving the yield of dipentaerythritol and the quality of pentaerythritol which is a main product, formaldehyde, alkali and acetaldehyde are partially charged in advance, and formaldehyde, alkali and acetaldehyde are respectively added thereto. A method has also been proposed in which the reaction is carried out by keeping the reaction at a theoretical molar ratio or higher and at a reaction temperature of 50 ° C. or lower and dropping them at the same time (Japanese Patent Publication No. 1-44689).

On the other hand, a method of synthesizing a mixture of polypentaerythritol from pentaerythritol using phosphoric acid, sulfuric acid, etc. is also known, but a means for selectively synthesizing dipentaerythritol has not been described (USP-246204).
7).

[0005]

However, the above-mentioned method for producing dipentaerythritol by the reaction of acetaldehyde and formaldehyde still has the following problems. (1) Pentaerythritol and dipentaerythritol must be separated and recovered from impurities such as by-produced sodium formate, bispentaerythritol monoformal, excess formaldehyde or acetaldehyde-formaldehyde self-condensate, and the purification process is complicated. Becomes (2) The production amount of dipentaerythritol depends on the production amount of pentaerythritol.
The limit is 10 to 15%, which cannot meet the recent increase in demand.

On the other hand, according to the knowledge of the present inventors, a method of dehydrating and condensing pentaerythritol by using an acid catalyst can obtain dipentaerythritol. Erythritol is converted to high-molecular-weight polypentaerythritol, or an intramolecular condensate is produced, so that it is difficult to put it to practical use as it is.

The inventors of the present invention have made extensive studies to solve the above problems and found that dipentaerythritol is produced when urea is reacted with pentaerythritol, and the inventors have previously proposed. However, it has been required to further improve the yield.

[0008]

Means for Solving the Problems The inventors of the present invention further conducted extensive studies to improve the yield of the above reaction, and as a result, when this reaction was carried out in the presence of a titanium catalyst, the yield of dipentaerythritol was increased. Therefore, the present invention has been completed and the present invention has been completed.

That is, the present invention is a method for producing dipentaerythritol, which comprises reacting pentaerythritol with ureas in the presence of a titanium catalyst. A method for producing dipentaerythritol from urea and pentaerythritol, and a method for carrying out this reaction in the presence of a titanium catalyst have not been reported so far, and the present invention is a novel method for producing dipentaerythritol. . Hereinafter, the present invention will be described in more detail.

In the method of the present invention, when reacting ureas with pentaerythritol, it is important to carry out the reaction in the presence of a titanium catalyst. Examples of the titanium catalyst used in the method of the present invention include trivalent and tetravalent metals such as titanium metal, divalent, trivalent and tetravalent titanium oxide, titanium fluoride, titanium chloride, titanium bromide and titanium iodide. Titanium halides, titanium sulfate, titanium hydroxide, titanium methoxide, titanium ethoxide, titanium isopropoxide, alkoxides such as titanium butoxide, titanium oxysulfate, titanium oxide salts such as titanium oxide acetylacetonate, titanocene dichloride, Bis (pentamethylcyclopentadienyl)
Titanocene such as titanium dichloride can be exemplified. Among these titanium catalysts, titanium oxide and titanium oxide acetylacetonate are preferable.

The pentaerythritol used as a raw material in the method of the present invention can be industrially produced by reacting formaldehyde and acetaldehyde in the presence of an alkali, and used as a raw material without further purification. it can.

[0012] Examples of urea, which is the other raw material, include N-methyl urea, N-ethyl urea, N,
Substituted ureas such as N'-dimethylurea, N, N'-diethylurea, N, N'-dibenzylurea, N, N'-diphenylurea and N, N-diethylurea can be exemplified. Among these ureas, urea is preferable in consideration of economy.

The amounts of ureas and pentaerythritol used in the method of the present invention are not particularly limited.
Pentaerythritol is used in an amount of 0.1 to 20 mol, preferably 0.5 to 10 mol, per 1 mol. If it is less than this range, the amount of dipentaerythritol produced is small and the amount of by-products of impurities increases, and if it is large, the amount of unreacted pentaerythritol recovered increases, which is economically disadvantageous.

In the present invention, ureas and pentaerythritol can be reacted in a molten state without using a solvent, but a solvent may be used if necessary. Examples of preferred solvents include dioxane, tetrahydrofuran, ethyl ether, anisole, phenyl ether, diglyme, tetraglyme, ethers such as 18-crown-6,
Esters such as methyl acetate, ethyl butyrate, methyl benzoate, γ-butyrolactone, acetone, acetophenone,
Ketones such as benzophenone, N-methylpyrrolidine-2-
On, N, N-dimethylacetamide, N-methylpiperidone, N-substituted amides such as hexamethylphosphoric triamide, N, N-diethylaniline, N-methylmorpholine,
Of tertiary amines such as pyridine and quinoline, sulfones such as sulfolane, sulfoxides such as dimethyl sulfoxide, urea derivatives such as 1,3-dimethyl-2-imidazolidinone, and phosphine oxides such as tributylphosphine oxide. Other examples include silicone oil and water.
Among these solvents, N-substituted amides, sulfones, urea derivatives, water and the like are preferable. These solvents can be used alone or as a mixed solvent.

In the method of the present invention, the reaction temperature is 100 to 250 ° C.
The reaction is preferably carried out at 120 to 220 ° C. Reaction temperature 100
If the temperature is less than ℃, the reaction rate is extremely slow, and if it exceeds 250 ℃, the by-product of impurities increases. The reaction pressure may be a pressure that can maintain a predetermined reaction temperature. Usually, it is 1 to 50 kg / cm ² . If necessary, the reaction pressure may be argon, helium,
You may pressurize with inert gas, such as nitrogen. The reaction time varies depending on the reaction temperature, the type of catalyst, etc., but is usually 0.05 to 100 hours, preferably 0.1 to 80 hours.

The method of the present invention can be carried out by any of a batch method, a semi-batch method and a continuous method. For example, in the case of the batch method, urea is charged with pentaerythritol, a solvent and a titanium catalyst in a reactor, and the reaction proceeds while heating. In the case of the continuous method, the reaction is carried out by continuously supplying urea, pentaerythritol, a solvent and a titanium catalyst to one of the reactors and continuously withdrawing the reaction mixture from the other.

[0017]

EXAMPLES The present invention will now be described in more detail with reference to examples.

Example 1 In a glass four-necked flask having an internal volume of 500 ml equipped with a thermometer, an air-cooled tube and a stirrer, 136 g of pentaerythritol (1.
0 mol), urea 60 g (1.0 mol), titanium oxide acetylacetonate 1.3 g (0.005 mol) and sulfolane 1 as a catalyst.
00g was put, and it heated with the oil bath and heated at 170 degreeC for 6 hours. Ammonia gas generated during this period was purged out of the reaction system through an air cooling tube. After 6 hours, the reaction temperature was raised to 190 ° C., and the reaction was continued for 8 hours. After the reaction, the reaction solution was analyzed by gas chromatography to find that 21.2 g (0.083 mol) of dipentaerythritol was produced, and the yield based on the starting material pentaerythritol was 16.7%.

Example 2 A reaction was carried out in the same manner as in Example 1 except that the reaction time at 190 ° C. was changed to 16 hours. After the reaction
When the reaction liquid was analyzed by gas chromatography, 25.2 g (0.099 mol) of dipentaerythritol was produced, and the yield based on the starting material pentaerythritol was 19.8%.

Example 3 The reaction was performed in the same manner as in Example 1 except that 0.64 g (0.010 mol) of titanium oxide (divalent) was used instead of titanium oxide acetylacetonate. After the reaction, when the reaction liquid was analyzed by gas chromatography, 20.6 g (0.081 mol) of dipentaerythritol was produced, and the yield based on the starting material pentaerythritol was 16.2%.

Example 4 The reaction was performed in the same manner as in Example 1 except that 0.56 g (0.005 mol) of titanium chloride (tetravalent) was used instead of titanium oxide acetylacetonate. After the reaction, the reaction solution was analyzed by gas chromatography to find that 18.1 g (0.071 mol) of dipentaerythritol was produced, and the yield based on the starting material pentaerythritol was 14.2%.

Example 5 The reaction was performed in the same manner as in Example 1 except that 1.24 g (0.005 mol) of titanocene dichloride was used instead of titanium oxide acetylacetonate. After the reaction, when the reaction liquid was analyzed by gas chromatography, 17.3 g (0.068 mol) of dipentaerythritol was produced, and the yield based on the starting material pentaerythritol was 13.6%.

Example 6 The reaction was performed in the same manner as in Example 1 except that 1.20 g (0.005 mol) of titanium sulfate was used instead of titanium oxide acetylacetonate. After the reaction, the reaction solution was analyzed by gas chromatography to find that 16.3 g (0.064 mol) of dipentaerythritol was produced, and the yield based on the starting material pentaerythritol was 12.8%.

Comparative Example 1 The reaction was carried out in the same manner as in Example 1 except that titanium oxide acetylacetonate was not used as a catalyst. As a result, dipentaerythritol contained 4.9 g (0.0
(19 mol) was produced, and the yield based on the starting material pentaerythritol was 3.8%.

[0025]

Industrial Applicability According to the method of the present invention, dipentaerythritol can be efficiently produced from urea and pentaerythritol which are industrially available at low cost, which is extremely advantageous industrially and economically.

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Claims (1)

[Claims] 1. A process for producing dipentaerythritol, which comprises reacting pentaerythritol with ureas in the presence of a titanium catalyst.