JPH07165651A - Production of dipentaerythritol - Google Patents

Abstract

PURPOSE:To efficiently obtain dipentaerythritol useful as e.g. a raw material for producing polyesters, etc., in high yield by reaction between pentaerythritol and an urea compound in the presence of an alkali catalyst. CONSTITUTION:Dipentaerythritol is obtained by reaction between pentaerythritol and an urea compound such as N-methylurea in the presence of an alkali catalyst pref. at 120-220 deg.C. It is preferable that the amount of the alkali catalyst to be used be 0.01-300 gram atom in terms of alkali(alkaline earth) metal based on 100mol of the pentaerythritol.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a novel method for producing dipentaerythritol. Dipentaerythritol is useful as a raw material for polyester, polyether, polyurethane, alkyd resin, lubricating oil and the like.

[0002]

BACKGROUND OF THE INVENTION Dipentaerythritol is a by-product in the synthetic reaction of pentaerythritol, that is, in the reaction of formaldehyde with acetaldehyde in the presence of alkali to produce pentaerythritol.
A general industrial production method is obtained by separating and purifying this (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 a part of acetaldehyde are charged in advance, and formaldehyde, alkali and acetaldehyde are added to each theoretical molar ratio. A method has also been proposed in which the above is maintained and the reaction temperature is kept at 50 ° C. or lower and the reaction is carried out by dropping simultaneously (Japanese Patent Publication No. 1-44689).

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

[0004]

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, the method of dehydration condensation of pentaerythritol using an acid catalyst can obtain dipentaerythritol according to the knowledge of the present inventors, but the produced dipentaerythritol is tripentacyclic. 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.

[0006]

Means for Solving the Problems The inventors of the present invention have made extensive studies to solve the above problems. As a result, they found that dipentaerythritol was efficiently produced when urea was reacted with pentaerythritol in the presence of an alkali catalyst, and the present invention was completed. So far
A method for producing dipentaerythritol from ureas and pentaerythritol has not been reported, and the present invention is a novel method for producing dipentaerythritol. Although the reaction mechanism in the method of the present invention is not clear, 3,3-
Since the presence of bis (hydroxymethyl) oxetane is recognized, it can be presumed that bis (hydroxymethyl) oxetane is passed through oxetane as a reaction intermediate.

The present invention will be described in more detail below.

In the method of the present invention, it is important to react ureas with pentaerythritol in the presence of an alkali catalyst. Examples of the alkali catalyst used include alkali metal hydroxides, alkaline earth metal hydroxides, alkoxides, carbonates, and carboxylates. For example, lithium hydroxide, sodium hydroxide, potassium hydroxide, magnesium hydroxide, calcium hydroxide, lithium methoxide, lithium ethoxide, lithium isopropoxide, sodium methoxide,
Sodium ethoxide, sodium isopropoxide, lithium carbonate, sodium carbonate, potassium carbonate, magnesium carbonate, calcium carbonate, lithium acetate, sodium acetate, potassium acetate, magnesium acetate, calcium acetate, lithium propionate, sodium oxalate, potassium laurate, Magnesium formate etc. can be illustrated.
Of these alkali catalysts, alkali metal hydroxides, alkaline earth metal hydroxides, and alkoxides are preferable.

The amount of these alkali catalysts used is 0.01 to 300 gram atom, preferably 0.1 to 200 gram atom, more preferably 0.1 to 200 gram atom as an alkyl metal or an alkyl earth metal per 1000 mol of pentaerythritol used in the reaction. It is 1.0 to 100 gram atom.

The pentaerythritol used as a raw material in the method of the present invention can be industrially produced by reacting formaldehyde with acetaldehyde in the presence of alkali, and used as a raw material without further purification. it can. Examples of urea, which is the other raw material, include, in addition to urea, N-methylurea, N-ethylurea, N, N'-dimethylurea, N, N'-diethylurea, N, N '. Examples include substituted ureas such as dibenzylurea, N, N′-diphenylurea and N, N-diethylurea. Among these ureas, urea is preferable in consideration of economy.

The amounts of urea 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 hydrocarbons such as benzene, xylene and decalin, dioxane, tetrahydrofuran, ethyl ether, anisole, phenyl ether, diglyme, tetraglyme, ethers such as 18-crown-6, methyl acetate, ethyl butyrate. , Methyl benzoate, γ-butyrolactone and other esters, acetone, acetophenone, benzophenone and other ketones, N-methylpyrrolidin-2-one, N,
N-substituted amides such as N-dimethylacetamide, N-methylpiperidone, and hexamethylphosphoric triamide, N,
N-diethylaniline, N-methylmorpholine, pyridine,
Tertiary amines such as quinoline, sulfones such as sulfolane, sulfoxides such as dimethyl sulfoxide, 1,
In addition to urea derivatives such as 3-dimethyl-2-imidazolidinone and phosphine oxides such as tributylphosphine oxide, silicon oil, water and the like can be exemplified. Among these solvents, hydrocarbons, 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.
The reaction is carried out at ℃, preferably 120-220 ℃. The reaction temperature is
If it is less than 100 ° C, the reaction rate is extremely slow, and if it exceeds 250 ° C, the by-product of impurities increases. The reaction pressure may be a pressure that can maintain a predetermined reaction temperature. Usually 1 to 50 kg / c
m ² . If necessary, the reaction pressure may be increased with an inert gas such as argon, helium or nitrogen. The reaction time varies depending on the reaction temperature and the like, 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, as an example in the case of the batch method, urea and pentaerythritol, a solvent and an alkali catalyst are charged 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, the solvent and the alkali catalyst to one of the reactors and continuously withdrawing the reaction mixture from the other.

[0015]

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

Example 1 Internal volume of 500 m equipped with a thermometer, condenser and stirring device
136 g of pentaerythritol (1.
0 mol), 60 g (1.0 mol) of urea and 3.3 g (0.05 mol) of 85% potassium hydroxide as a catalyst were charged, and the reactor was heated in an oil bath. After the temperature was raised to 190 ° C in 50 minutes, the reaction was continued at 190 ° C for 4 hours. After the reaction, the reaction liquid was analyzed by gas chromatography. As a result, dipentaerythritol was produced in a yield of 7.8% and tripentaerythritol was produced in a yield of 3.6% with respect to pentaerythritol used as a raw material.

Example 2 In Example 1, the amount of potassium hydroxide used was 0.33 g (0.0
The reaction was performed in the same manner as in Example 1 except that the amount was changed to 05 mol). After the reaction, when the reaction solution was analyzed by gas chromatography, the yield of dipentaerythritol was 3.5% and the yield of tripentaerythritol was 2.2% with respect to pentaerythritol used as a raw material. Bis (hydroxymethyl) oxetane was produced in a yield of 7.9%.

Example 3 In Example 1, the amount of potassium hydroxide used was 1.33 g (0.02
The reaction was performed in the same manner as in Example 1 except that the content was changed to (mol).
After the reaction, the reaction solution was analyzed by gas chromatography to find that the pentaerythritol used as the raw material had a yield of 7.0% for dipentaerythritol and 2.5% for tripentaerythritol. Bis (hydroxymethyl) oxetane was produced in a yield of 3.8%.

Example 4 In Example 2, a Liebig condenser was mounted and 100 g of xylene was used as a solvent. The reactor was heated and refluxed at the boiling point of xylene for 2 hours, and then xylene was distilled out of the system. After that, the reaction temperature was kept at 190 ° C. and the reaction was continued for 2 hours. After the reaction, the reaction solution was analyzed by gas chromatography to find that the yield of dipentaerythritol was 6.7% and the yield of tripentaerythritol was 2.4% with respect to pentaerythritol used as a raw material.
3-bis (hydroxymethyl) oxetane was produced in a yield of 5.1%.

Example 5 The reaction was carried out in the same manner as in Example 1 except that potassium hydroxide was replaced with 2.0 g (0.05 mol) of sodium hydroxide. After the reaction, the reaction solution was analyzed by gas chromatography to find that the yield of dipentaerythritol was 6.
The yield of tripentaerythritol was 6%, and the yield of 3,3-bis (hydroxymethyl) oxetane was 2.
It was generated at 0%.

Example 6 A reaction was carried out in the same manner as in Example 1 except that calcium hydroxide was changed to 1.9 g (0.025 mol) in place of potassium hydroxide. After the reaction, the reaction liquid was analyzed by gas chromatography to find that the yield of dipentaerythritol was 5.
5%, tripentaerythritol yield 1.9%, and 3,3-bis (hydroxymethyl) oxetane yield 2.
It was generated at 2%.

Example 7 The reaction was carried out in the same manner as in Example 1 except that potassium hydroxide was replaced with sodium etoxide in 3.4 g (0.05 mol). After the reaction, when the reaction liquid was analyzed by gas chromatography, the yield of dipentaerythritol was 6.4% and the yield of tripentaerythritol was 2.2% with respect to pentaerythritol used as a raw material. Bis (hydroxymethyl) oxetane was produced in a yield of 1.8%.

Example 8 A reaction was carried out in the same manner as in Example 1 except that potassium carbonate was changed to 6.9 g (0.05 mol) in Example 1. After the reaction, when the reaction liquid was analyzed by gas chromatography, the yield of dipentaerythritol was 4.9% with respect to pentaerythritol used as a raw material.
The yield of tripentaerythritol was 1.8%.
3,3-bis (hydroxymethyl) oxetane was produced in a yield of 2.3%.

Example 9 A reaction was carried out in the same manner as in Example 1 except that potassium acetate was replaced by 4.1 g (0.05 mol) of sodium acetate. After the reaction, the reaction solution was analyzed by gas chromatography to find that the yield of dipentaerythritol was 4.7% based on pentaerythritol used as a raw material.
%, The yield of tripentaerythritol is 1.7%, and the yield of 3,3-bis (hydroxymethyl) oxetane is 2.
It was generated at 5%.

Comparative Example 1 The reaction was carried out in the same manner as in Example 1 except that potassium hydroxide was not used. After the reaction, the reaction solution was analyzed by gas chromatography to find that the yield of dipentaerythritol was 3.0% and the yield of tripentaerythritol was 3.5% with respect to pentaerythritol used as a raw material.
1.5% and 3,3-bis (hydroxymethyl)
Oxetane was produced in a yield of 8.0%.

Comparative Example 2 In Example 1, 97% sulfuric acid was used instead of potassium hydroxide.
The reaction was carried out in the same manner as in Example 1 except that 1.01 g (0.01 mol) was used. After the reaction, the reaction solution was analyzed by gas chromatography.The yield of dipentaerythritol was 3.2% and that of tripentaerythritol was 1.4% with respect to pentaerythritol used as a raw material.
Yield of 3,3-bis (hydroxymethyl) oxetane 9.1%
Was generated by.

[0027]

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.

Claims (2)

[Claims] 1. A method for producing dipentaerythritol, which comprises reacting pentaerythritol with ureas in the presence of an alkali catalyst. 2. The method for producing dipentaerythritol according to claim 1, wherein the amount of the alkali catalyst used is 0.01 to 300 gram atom as an alkali metal or alkaline earth metal with respect to 1000 mol of pentaerythritol.