JP2003335716A - Method for producing ditrimethylolpropane - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a new method for producing ditrimethylolpropane, capable of efficiently synthesizing the ditrimethylolpropane with high selectivity. <P>SOLUTION: In this method for producing the ditrimethylolpropane, trimethylolpropane is reacted with carbonate esters in the presence a basic catalyst at first, and then its reaction condition is shifted to an acid state. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a novel method for synthesizing ditrimethylolpropane (hereinafter abbreviated as di-TMP). di-TMP is useful as a raw material for polyacrylate, polyether polyol, polyurethane, alkyd resin, synthetic lubricating oil and the like.

[0002]

2. Description of the Related Art Di-TMP is trimethylolpropane (hereinafter
It is known to form as a by-product of manufacturing (abbreviated as TMP). See, for example, US Pat. No. 3,097,245. T
The industrial production of MP is synthesized by basic catalyst-catalyzed aldol condensation of n-butyraldehyde with formaldehyde and cross-Cannizaro reaction. Di-TMP is produced in this TMP production reaction process. After this aldol condensation-crossover Kanitzaro reaction, TMP is separated and recovered by a conventional method. For example, after concentration or without concentration, the reaction product liquid as a solvent, for example, isobutanol, butyl acetate, ethyl acetate, amyl alcohol, methyl ethyl ketone, methyl isobutyl ketone, hexyl alcohol, isopropyl ketone, isobutyraldehyde, n-butyraldehyde, Extract with one or a mixture of cyclohexanol and the like. By this method, a TMP extract containing substantially no sodium formate can be obtained. The crude TMP thus obtained is purified by distillation under high vacuum. In general, di-TMP is recovered by crystallization from the bottom residue after the above high vacuum, that is, the distillation bottom residue. Usually, TMP1-10% and di-TMP20-50% are contained in the distillation still residue, and the remaining organic substances are cyclic or linear formal compounds. British Patent No. 1,
No. 291,335 describes that distiller residue is dissolved in an organic solvent or water and then crystallized to obtain di-TMP. However, this method requires repeated recrystallization steps to obtain high-purity di-TMP, which is disadvantageous from an industrial viewpoint.
The biggest problem with the method of recovery from distillation bottoms is that it is greatly affected by the production volume of TMP equipment. Since Di-TMP is a by-product of TMP synthesis, its production amount is proportional to the production amount of TMP equipment. Moreover, di-TMP produced as a by-product is about 1/10 of the TMP production amount, which is not suitable for mass production.

Therefore, studies have been made to obtain di-TMP by a synthetic method. For example, as in JP-A-8-157401 and JP-A-9-268150, TMP, formaldehyde, and aldehydes are removed in the presence of a base. There is something to react. But,
These methods are disadvantageous from an industrial point of view because the purification process becomes very long. On the other hand, a method of direct synthesis by dimerization of TMP has also been reported. For example, US Pat.
The publication describes a method of obtaining di-TMP by dehydration condensation of TMP with an acid in a solvent such as xylene or toluene. In addition, Japanese Patent Publication No. 6-501470 discloses a method of obtaining di-TMP by dehydration condensation of TMP protected with acid or TMP protected with ester. However, when TMP is condensed, a large amount of trimer or higher oligomer components are by-produced, and therefore the reaction rate must be extremely low. Further, when TMP protected with an ester is used, it is necessary to carry out an esterification or a deprotection reaction, which complicates the production process. Further, all of these methods have a problem of intense coloring.

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention
It is to provide a novel manufacturing method for efficiently synthesizing MP with high selectivity.

[0004]

Means for Solving the Problems As a result of studying a method for synthesizing di-TMP having the above-mentioned problems, the present inventors have found that a basic catalyst and a carbonate ester are added to TMP to form an ester. The present invention was completed by finding that di-TMP can be obtained with good selectivity by carrying out an exchange reaction, then a decarboxylation reaction, and then carrying out the reaction under an acidic condition.
That is, the present invention relates to a process for producing ditrimethylolpropane, which comprises reacting trimethylolpropane with carbonic acid esters in the presence of a basic catalyst and then shifting to acidic conditions. is there.

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION Trimethylolpropane (TMP), which is a raw material, is synthesized, for example, by an aldol condensation of n-butyraldehyde and formaldehyde under a basic catalyst and a crossed Cannitzaro reaction. A general industrial grade TMP can be used as it is and does not need to be purified again. Examples of the carbonate ester as the other raw material include dimethyl carbonate, diethyl carbonate, diisopropyl carbonate, dibutyl carbonate, ethylene carbonate and the like. General industrial grade products can be used as they are without having to re-purify.

There are no particular restrictions on the amount of carbonic acid ester and TMP used in the method of the present invention.
The TMP is 2 to 30 mol, preferably 5 to 10 mol per mol. If it is less than this range, the amount of di-TMP produced is small and the amount of by-produced TMP oligomer increases. on the other hand,
If it exceeds this range, the recovery amount of unreacted TMP will increase,
It is economically disadvantageous.

When carbonic acid esters are reacted with TMP, the reaction proceeds even if acidic or without a catalyst, but the reaction is efficiently started by starting the reaction in the presence of a basic catalyst and then shifting to acidic conditions to carry out the reaction. Di-TMP can be manufactured.

Examples of the basic catalyst used in the present invention include:
Alkali metal or alkaline earth metal hydroxides, alkoxides, carbonates, carboxylates and the like are used.
For example, lithium hydroxide, sodium hydroxide, magnesium hydroxide, calcium hydroxide, lithium methoxide, lithium ethoxide, lithium isopropoxide, sodium methoxide, sodium ethoxide, sodium isopropoxide, lithium carbonate, sodium carbonate, Examples include potassium carbonate, magnesium carbonate, calcium carbonate, lithium acetate, sodium acetate, potassium acetate, magnesium acetate, calcium acetate and the like.
These can be used alone or in combination of two or more.

The amount of the basic catalyst used is not particularly limited, but is usually 100 ppm to 10%, preferably 1000 ppm to 5000 ppm, relative to TMP. If it is less than this range, the reaction rate becomes extremely slow, and if it is more than that range, the reaction solution may be colored. There is no particular problem even if the catalyst remains solid or is used as an aqueous solution.

As the reaction conditions under the basic catalyst, first, the liberated alcohol is always withdrawn while the carbonate ester is refluxed. The reaction temperature at this time is usually 50 to 200 ° C.
The reaction time is usually 0.5 to 24 hours, preferably 1 to 10
It's time. By doing so, the free alcohol can be completely removed. After completely removing the liberated alcohol, the reaction solution is heated to 100 to 250 ° C, preferably 150
Keep at ~ 200 ° C. The reaction time at this time is usually 0.5 to 48 hours,
It is preferably 1 to 10 hours. By doing so, the TMP carbonate compound obtained by transesterification can be completely disappeared.

Next, the condition is changed to acidic. 10 ~
After cooling to 200 ° C, preferably 50-150 ° C, the acid is added. If the temperature at the time of addition is low, the reaction liquid has a high viscosity and the reaction efficiency is deteriorated. The acid used at this time is an inorganic acid such as phosphoric acid or sulfuric acid, an organic acid such as paratoluenesulfonic acid, or the like. These may be used as they are, or may be dissolved in water or the like. The amount of acid used may be equimolar or more to the previously used base catalyst. It is preferably 100 pp relative to TMP in addition to the equimolar amount of the base catalyst.
m-10%, preferably 1000-5000 ppm. The reaction under acidic conditions is carried out until the only component having a lower molecular weight than di-TMP in the reaction solution is TMP. Reaction temperature is 10 ~ 200
C., preferably in the range of 50 to 150.degree. The reaction time is
It is usually 0.1 to 24 hours, preferably 1 to 10 hours.

There is no limitation on the method of collecting and purifying di-TMP from the obtained reaction solution. Usually, it is purified by recrystallization or distillation after neutralization with a base such as sodium carbonate or sodium hydrogen carbonate. The amount of base required for neutralization is the stoichiometric equivalent to the acid used as the catalyst. The base used for neutralization may be used as it is or in the form of an aqueous solution. Usually, when di-TMP is recovered by distillation, it is first distilled under reduced pressure to separate unreacted TMP. Pressure is 1333Pa ~ 1P
a, preferably 666 Pa to 13 Pa. After separating TMP, distillation is performed under reduced pressure to recover di-TMP. It is usually performed under the conditions of 1333 Pa to 1 Pa, preferably 133 Pa to 5 Pa.
The distillate component is 190 to 192 ° C / 133Pa. For this distillation, a distillation column having about 3 theoretical plates may be used, but if necessary, a distillation column having more theoretical plates may be used. Further, the TMP separated here can be reused as a raw material of the present invention.

[0013]

EXAMPLES The present invention will be described in more detail below with reference to examples. However, the present invention is not limited to these examples.

Example 1 1000 ml equipped with a magnetic stirrer, a thermometer, and a distillation column equivalent to three stages
TMP 400.7g (2.99mol) and dimethyl carbonate 36.4g (0.4mol) in a three-neck flask, sodium carbonate 0.5g (5
mmol) and heat the reactor with a mantle heater to 80
℃. After a while, methanol was distilled out, so this was removed outside the system and the temperature was gradually raised (5 hours until it reached 190 ° C). 190 when it reaches 190 ℃
The reaction was continued for 4 hours while maintaining the temperature at ℃. The reaction solution was cooled to 100 ° C., and 2.4 g of 50% sulfuric acid was added. After stirring at 100 ° C for 30 minutes, the mixture was heated to 130 ° C and reacted for 1 hour.
Then, the solution was neutralized with 8.0 g of a 10% sodium carbonate aqueous solution, and vacuum distilled. 190 ℃, 1mmHg component was recovered,
When GC analysis was performed, it was di-TMP with a purity of 98%. Isolation yield 63.5 g, isolation yield 67% (at the end of the reaction, di-TMP selectivity based on TMP consumed was 79%).

Example 2 500 ml equipped with a magnetic stirrer, a thermometer, and a distillation column equivalent to three stages
TMP 250.0g (1.87mol) and dimethyl carbonate in a 3-neck flask
33.9g (0.38mol), 0.5g sodium carbonate as catalyst (5m
mol) and heat the reactor with a mantle heater to 80
℃. After a while, methanol was distilled out, so this was removed outside the system and the temperature was gradually raised (5 hours until it reached 190 ° C). When the reaction temperature reached 190 ° C, the reaction was continued at 190 ° C for 4 hours. The reaction solution was cooled to 100 ° C., and 1.6 g of 50% sulfuric acid was added. 100 ° C
The mixture was stirred as it was for 30 minutes, heated to 130 ° C., and reacted for 1 hour. Then, the solution was neutralized with 4.0 g of a 10% sodium carbonate aqueous solution, and vacuum distilled. When the component of 190 mm and 1 mmHg was recovered and analyzed by GC, it was 98% pure di-TMP. Isolation yield 42.9g, isolation yield 62% (At the end of the reaction, consumption T
MP mole standard di-TMP selectivity 72%).

Comparative Example 1 The reaction was carried out by the method described in US Pat. No. 3,673,226. 268 g (2.0 mol) of TMP and 150 g of toluene were placed in a flask equipped with a magnetic stirrer, a thermometer, a heating mantle heater, and a Dean-Stark water separator. P-toluenesulfonic acid
After adding 2 g, the mixture was heated to 200 ° C. with stirring, whereby a part of toluene was distilled off. The mixture was refluxed at this temperature until 18 g of water had been separated by the separator. The mixture
The mixture was cooled to 100 ° C and neutralized with 1N sodium carbonate. Water and toluene were distilled off at 100 ° C. and 15 mmHg. This gave 242.5 g of a tan viscous oil containing 34.1 g of di-TMP, 7.1 g of tri-TMP and 110.5 g of unreacted TMP.
The selectivity of di-TMP was calculated to be 23.2% (generation
di-TMP mol / theory di-TMP mol × 100).

Comparative Example 2 The reaction was carried out by the method described in Japanese Patent Publication No. 6-501470. TMP1210g (9.0mol) and sulfuric acid 0.62g were put into the flask provided with the heating mantle heater, the magnetic stirring bar, and the reflux condenser. The device was adjusted to a pressure of 6 mmHg. The mixture was heated to a temperature of 160-165 ° C. After 4 hours, 89.1g di-T
MP was produced in the reaction solution. At the same time 7.1 g of tri-TMP was present in this solution. The TMP remaining in the reaction solution
It was 1042 g. The calculated selectivity of di-TMP is 56.9.
% (Generation di-TMP mol / theory di-TMP mol × 10
0).

[0018]

As is apparent from the above examples, according to the present invention, di-TMP can be efficiently produced with good selectivity.

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Masafumi Watanabe             3-10 Mizushima Kaigan Dori, Kurashiki City, Okayama Prefecture             Ryo Gas Chemical Co., Ltd. Mizushima Plant (72) Inventor Junichi Amamiya             3-10 Mizushima Kaigan Dori, Kurashiki City, Okayama Prefecture             Ryo Gas Chemical Co., Ltd. Mizushima Plant F-term (reference) 4H006 AA02 AC43 BA02 BA03 BA06                       BA29 BA32 BC31 BE03 BE04                 4H039 CA61 CD10 CD30

Claims (2)

[Claims] 1. When reacting trimethylolpropane with carbonic acid esters, the reaction is initiated in the presence of a basic catalyst,
Then, a method for producing ditrimethylolpropane, which comprises shifting to acidic conditions. 2. The reaction of trimethylolpropane in the range of 2 to 30 mol with respect to 1 mol of the carbonic acid ester.
The method for producing ditrimethylolpropane according to 1.