JPH02129152A - Production of alicyclic diamines - Google Patents

Abstract

PURPOSE:To obtain the subject compound useful as a raw material for polyamide resin, non-yellowing polyurethane resin, epoxy resin hardener, etc., by hydrogenating an aromatic amine in the presence of palladium and ruthenium catalyst. CONSTITUTION:An alicyclic diamine is produced by hydrogenating an aromatic diamine in the presence of palladium and ruthenium catalyst in a solvent such as dioxan or in the absence of solvent under a hydrogen pressure of 10-300kg/cm<2> at 100-230 deg.C for 0.5-6hr. The weight ratio of Pd to Ru used as the catalyst is preferably (0.001-2)/1 and the amount of the catalyst is 0.0001-0.5 pts.-wt. in terms of metal based on the diamine. The catalyst is usually supported on a carrier such as alumina or diatomaceous earth. Both catalysts are used at the same time in the reaction of the diamine used as a raw material or the diamine is first reacted in the presence of Pd and then Ru.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a method for producing corresponding alicyclic diamines by hydrogenating aromatic diamines as raw materials.

BACKGROUND ART Conventionally, in order to hydrogenate aromatic diamines, a method is known in which a noble metal such as ruthenium or rhodium is used as a catalyst, or alkali-modified cobalt is used as a catalyst. JP-A-55-108839 and US Pat. No. 3,959,374 disclose a method using ruthenium as a catalyst, and JP-A-62-228J) 44 (EP 2317)
88) discloses catalysts consisting of ruthenium and rhodium, respectively. Among these methods, methods using ruthenium catalysts are widely used industrially, but since the ruthenium catalyst is very expensive, efficiency of hydrogenation, retention of catalyst activity, etc. are always desired.

In order to solve this problem, it was first essential to remove the micro-crushed by-products that caused poisoning and were contained in the raw aromatic amines.

In addition, many by-products generated during hydrogenation often coat the catalyst and reduce the catalytic activity, so it is also an important issue to suppress the formation of these by-products during the reaction process. Ta.

Conventionally, two methods have been taken to address these problems: purification of aromatic amines as raw materials and replenishment of a new ruthenium catalyst to the reaction system to supplement the poisoned catalyst.

Recrystallization and distillation methods were used to purify raw materials. However, the recrystallization method has many side problems such as a decrease in yield due to recrystallization loss, recovery of solvent, and handling of solid powder, resulting in a disadvantageous situation such as a decrease in production efficiency and an increase in processing costs. I will invite you. In addition, regarding the distillation method, aromatic amines generally have a high boiling point, and in order to remove impurities such as oxides as residue, most of the charged amine must be distilled out, so the loss in terms of thermal energy is I can't ignore it. In any case,
Conventional raw material refining involves technically complicated steps and is not necessarily an effective method from the economic standpoint of production. On the other hand, replenishing ruthenium catalyst is not a preferable method because it is closely associated with an increase in the cost of hydrogenation, and in particular, replenishing new ruthenium catalyst is not a good idea in the long run because it means replacing the catalyst.

Against this background, the conventional techniques are not necessarily sufficient as industrial production methods, and there is a desire to develop a more advantageous production method.

Problems to be Solved by the Invention The present invention aims to provide a new method for producing alicyclic diamines based on the knowledge that a combination of palladium and ruthenium catalysts is useful for suppressing side reactions and maintaining catalyst activity. be.

Means for Solving the Problems The present invention relates to a method for producing alicyclic diamines, which is characterized by hydrogenating aromatic diamines in the presence of a palladium and ruthenium catalyst.

Here, the order of aromatic diamines is the following formula (1) and (
A compound represented by II) is exemplified.

(In the formula, R represents hydrogen or lower alkyl) or differently hydrogen or lower alkyl);
R has the same meaning as above] Here, the lower alkyl in formulas (1) and ([1)] refers to linear or branched C1-C4 methyl, ethyl, propyl, isopropyl, butyl, isobutyl, 5
Examples include ec-butyl and tert-butyl.

The composition weight ratio of palladium and ruthenium in the catalyst is 0001
/1 to 2/l is preferable, and the amount of the catalyst used is 0.0001 to 0.05 parts by weight, preferably 0.001 to 0.01 parts by weight, based on the diamine as the raw material. Further, these catalysts are usually supported by a carrier, and examples of the carrier include alumina, diatomaceous earth, and the like.

The reaction is carried out without a solvent or in a solvent that does not participate in the reaction. As a suitable solvent, ethers such as dioxane and tetrahydrofuran are preferably used, and are used in an amount of 0 to 5 parts by weight, preferably 1 to 3 parts by weight, based on the diamine as the raw material. Also, the hydrogen pressure in the hydrogenation reaction is lO
~300 kg/ei, preferably 35-200 kg/ei
It is cI11.

The reaction temperature is usually 100 to 230°C, and the reaction is completed in 0.5 to 6 hours. After the reaction is completed, the target compound can be obtained in high purity by conventional isolation and purification methods, for example, by filtering the catalyst and then distilling it under reduced pressure.

In addition, in the production method of the present invention, the respective roles of palladium and ruthenium as catalysts are considered to be different. That is, palladium primarily attacks catalyst poisoning substances,
Ruthenium is effective in detoxifying aromatic rings, and ruthenium is effective in hydrogenating aromatic rings.

Therefore, in practice, it is preferable to use both catalysts simultaneously for the raw material diamine, or to treat the raw material diamine with palladium before using ruthenium. Therefore, there are two methods for hydrogenation: one is a batch operation in an autoclave using a catalyst containing predetermined drops of palladium and ruthenium, and the other is a fixed bed hydrogenation device in which the catalyst is continuously introduced.

However, it is an important choice in industrial practice whether to use both catalysts in a mixed form or whether to separate the treatment of palladium and ruthenium into two stages.

In general, mixed mode processes are advantageous when working in batch reactors. In addition, when continuously treating a large amount of aromatic diamine, it is preferable to process in a mixed form if one wants to use only one reactor, and if two reactors are used, a two-step process can be used. .

In any case, it can be said that it is efficient to bring the raw amine into contact with palladium and the ruthenium catalyst simultaneously or with palladium first.

The present invention makes it possible to efficiently carry out the reaction by reducing the amount of catalyst required to complete the reaction, lowering the reaction temperature, shortening the time required for the reaction, suppressing side reaction products, and resulting in a longer life of the ruthenium catalyst. can be extended further.

The alicyclic diamines obtained by the present invention are useful compounds as raw materials for polyamide resins, non-discoloring polyurethane resins, curing agents for epoxy resins, and the like.

Aspects of the present invention will be explained below using experimental examples and examples.

Experimental example 1 In case of ruthenium catalyst alone, internal volume 500m
Crude 3.37-dimethyl-4.4'-diaminodiphenylmethane (hereinafter referred to as MD
(denoted as T) 100g, dioxane 200g as a solvent,
As a catalyst, 20 g of a 0.5% ruthenium-alumina catalyst (manufactured by Nippon Engelhard) was charged. After hydrogen substitution, the hydrogen pressure was set to 50 kg/cj and the mixture was heated to 200 ml while stirring.
The temperature was raised to ℃, and then the hydrogen pressure was immediately increased to 100 kg/cI.
The progress of hydrogen absorption was measured as It, using the degree of reduced pressure as a guide. The progress of the reaction was measured based on the point at which the hydrogen pressure was set to 100 kg/cd (starting point), and the point at which the pressure reduction reached its limit was defined as the end point. That is, the time required for the reaction is the elapsed time from the starting point, and the reaction rate was calculated based on the degree of pressure reduction at the end point.

Thereafter, the contents were cooled to room temperature and replaced with depressurized nitrogen.
It was filtered under reduced pressure using α5C p paper (manufactured by Toyo Roshi Co., Ltd.).

After concentration, the p liquid was analyzed for purity using gas chromatography.

The purity of the crude MDT used here as a starting material was 94.5% as determined by gas chromatography, and the rest was impurities. The impurities included a compound in which three toluidine nuclei were bonded with methylene groups in between, and a small amount of tar as a high condensate.

It was set at 14. That is, each time of recovery, 1.0 g of new ruthenium catalyst was added, 100 g of crude MDT and 200 g of dioxane were newly charged, and the reaction was repeated.

The results are shown in Table 1.

Table 1 The ratio of the content of silmethane (HMDT) was defined as the yield. This is designated as experiment number 11.

Thereafter, 1.0 g of a new ruthenium catalyst was added to the recovered catalyst, and 100 g of crude MDT and 200 g of solvent dioxane were charged in the same manner as above to synthesize HMDT. Hydrogen pressure 10
0 kg/c++1. The reaction progress time is measured based on the time when the temperature is set at 200° C., and the method of analyzing the product is the same as described above. This will be referred to as Experiment 12.

These operations were repeated, and the following Experiment 13゜Experiment Example 2 In the case of palladium-ruthenium catalyst, 100 g of crude MDT and dioxane 2 as a solvent were added according to Experiment Example 1.
00g, catalyst 2 in which 0.5% palladium-alumina and 0.5% ruthenium-alumina (both manufactured by Nippon Engelhard) were mixed at a weight ratio of 1=10.
0g was charged.

The following: synthesis of HMDT, measurement of reaction progress, filtration collection,
The details of the repeated experiment can be found in Experimental Example 1.

That is, in each repetition, 1.0 g of new catalyst was added, 100 g of crude MDT, and 200 g of dioxane were charged, and the reaction was monitored.

The results are shown in Table 2.

Table 2 It was not detected by chromatographic measurements.

In the second step, the operation of Experimental Example 1 was repeated using the above treatment liquid as a starting material.

The results are shown in Table 3.

Table 3 Experimental Example 3 In the case of two-stage treatment, in the first stage crude MDT loog, dioxane 3
00g and 2.0g of 5% palladium-alumina catalyst were charged into an autoclave and replaced with hydrogen.Then, the hydrogen pressure was set to 50kg/cj and the temperature was raised to 150°C with stirring. After reaching 150° C., it was left to stand for 60 minutes, and then cooled to complete the first stage treatment. With this operation, MDT
Gask Experimental Examples 1 to 3 show the loss of aromatic diamine (MDT).
) is used as a raw material for hydrogenation, and a comparison is made between using ruthenium alone and treating it with palladium-ruthenium.

Experimental Example 1 shows that the activity of the ruthenium catalyst decreases rapidly. That is, it is clear from a comparison of the time required for a given level of reaction rate that the activity is halved by repeating the reaction 2 to 3 times.

On the other hand, according to Experimental Example 2, the rate of deactivation is quite slow. This can be interpreted to be because the palladium-ruthenium catalyst significantly detoxifies poisonous substances during hydrogenation.

Further, a similar tendency is also demonstrated by Experimental Example 3. Repeated experiments (32, 33, 34) have shown that if the crude MDT raw material is hydrogenated in advance in the first stage, the activity of the ruthenium catalyst in the second stage is well maintained at a given reaction rate. This is clear from the fact that the arrival times are similar. In both the methods of Experimental Examples 2 and 3, the palladium-ruthenium combination effect is clear.

From the results of the above experimental examples, when hydrogenating an aromatic diamine as a starting material to synthesize an alicyclic diamine, if hydrogenation is performed using a palladium-ruthenium catalyst, the ruthenium catalyst will always be It was demonstrated that the reaction could proceed efficiently while maintaining a high level of activity.

Example: In an autoclave with a stirring device and an internal volume of 500 m1, crude M
DT (purity 94.5%>100 g, 200 g of dioxane as a solvent, and 50 g of a catalyst prepared by mixing 0.5% palladium-alumina and 0.5% ruthenium-alumina in a ratio of 1=IO) were charged.

After hydrogen substitution, the temperature was raised to 180° C. with stirring at a hydrogen pressure of 50 kg/cut, and then the hydrogen pressure was immediately raised to 100 kg/cut to start the reaction.

After reacting under the same conditions for 3 hours, it was cooled to room temperature.

After depressurizing, nitrogen substitution was performed, and the catalyst was removed by filtration under reduced pressure. The solvent of the ρ solution was distilled off under reduced pressure to obtain 106.3 g of a pale brown viscous liquid. As a result of measurement by gas chromatography, the HMDTfi degree was 90.1%.

Based on the MDT content in the raw MDT, the generated H
The reaction yield of MDT was 96.4%.

Crude HMDT was distilled under reduced pressure to 129-131 tl: 10
．． 94.3 g (purity 97.8%) of a 3 amHg fraction was obtained.

Including distillation purification, the yield was 90.7%.

The obtained HMDT had analytical values of gas chromatography, mass spectrum, nuclear magnetic resonance spectrum, and infrared absorption spectrum that all agreed with standard HMDT (trade name: Laromin C260; manufactured by BASF).

Effects of the Invention The present invention provides a novel method for producing finger-type diamines from aromatic diamines.

Claims (3)

[Claims] (1) A method for producing alicyclic diamines, which comprises hydrogenating aromatic diamines in the presence of a palladium and ruthenium catalyst. (2) The production method according to claim (1), characterized in that hydrogenation is carried out in the coexistence of palladium and ruthenium catalysts. (3) The method according to claim (1), characterized in that the reaction is carried out in the presence of a palladium catalyst, and then hydrogenation is carried out in the presence of a ruthenium catalyst.