JPS60239444A - Preparation of cyclohexylamine - Google Patents

Abstract

PURPOSE:To obtain the titled compound by inexpensive plant cost without requiring an expensive autoclave, by using an inexpensive molded catalyst of nickel type as a catalyst, reacting phenol with hydrogen and ammonia in a vapor phase, subjecting the formed reaction solution to fractional distillation. CONSTITUTION:A molded catalyst of nickel type is used as a catalyst, phenol, hydrogen, and ammonia in gaseous state are introduced onto the catalyst, reducing amination reaction is carried out, and the prepared reaction solution is subjected to fractional distillation, to give the desired compound. A molar ratio of phenol: hydrogen: ammonia is 1:(5-30):(1-10), preferably 1:(8-20):(1-6), the reaction temperature is 100-250 deg.C, preferably 130-180 deg.C. Diatomaceous earth is used as a carrier for the catalyst used in the reaction. The fractional distillation residue in the reaction solution comprises dicyclohexylamine as a main component, it is blended with phenol, the blend together with ammonia and water is fed onto the catalyst, and reduced to give the titled compound.

Description

Detailed Description of the Invention The present invention relates to a cyclohexylamine which is characterized in that phenol is passed in gaseous form over a nickel-based shaped catalyst together with hydrogen and ammonia to carry out a reductive amination reaction, and the resulting reaction solution is fractionated. This relates to the manufacturing method.

Conventional methods for producing cyclohexylamine include a method by hydrogenating aniline and a method by aminating cyclohexanol, and these methods are also used industrially. However, recently, a method has been proposed in which cyclohexylamine is synthesized in one step by reacting phenol with hydrogen and ammonia to carry out a so-called reductive amination reaction. For example, Br1t 1031169 (Japanese Patent Publication No. 41-15103) is a pressurized liquid phase method in the presence of a rhodium catalyst, and Japanese Patent Publication No. 49-34677 is a pressurized liquid phase method in the presence of a ruthenium catalyst.

Also, Japanese Publication No. 55-51042 and Hamada et al. Chem1
gtry Lettsrsl 980 (3) 239
-240 both use an armpit radium catalyst.

That is, as a reductive amination technology of phenol, Rh,
In reality, it is common knowledge that a noble metal catalyst such as Ru or Pd must be used. The present inventors have examined these conventional techniques one by one and conducted detailed research, and as a result, it has been found that gas phase reductive amination of phenol is possible by using an inexpensive nickel-based synthetic catalyst instead of using a noble metal catalyst. We discovered this and arrived at the present invention. This is a completely new discovery that could not have been conceived from the concept of conventional technology, which was thought to be possible without the use of precious metal catalysts.

The characteristics of the present invention are: firstly, it uses an inexpensive nickel-based molded catalyst as a catalyst, and secondly, because it is a gas phase reaction, there is no need for an expensive autoclave, and in some cases, even fractional distillation is necessary. Since cyclohexylamine can be produced in a continuous manner, the equipment cost is lower than that of conventional techniques, and it can be said to be an industrially extremely valuable method for producing cyclohexylamine.

In addition to cyclohexylamine, the reaction solution obtained by the method of the present invention contains dicyclohexylamine as a main component and some high-boiling substances such as cyclohexylaniline.

This can be fractionated to collect the product cyclohexylamine. By-products mainly composed of dicyclohexylyanone obtained as a high boiling point are converted to dicyclo by adding an appropriate amount of phenol and passing it over the same nickel-based shaped catalyst together with excess ammonia and hydrogen to react as described below. The bulk of indylamine is converted to hexylamine.

Therefore, by combining this process with the above-mentioned process, only dicyclohexylamine can be produced.

However, it is not necessarily necessary to carry out both of these processes separately, and by selecting reaction conditions, it is possible to constantly charge an appropriate amount of all high-boiling substances, including dicyclohexylamine, into the reaction system, thereby operating only the reaction column packed with the nickel-based shaped catalyst. Cyclohexylamine can be produced through fractional distillation. In this case, the amount of phenol charged may be reduced by the amount of high-boiling substances including dicyclohexylamine added.

In the nickel-based shaped catalyst used in the present invention, diatomaceous earth, pumice, alumina, silica, etc. are used as a carrier, and a small amount of another metal such as copper may be added to the nickel as a co-catalyst depending on the case. However, from the viewpoint of ease of production, handling, and cost, a nickel shaped catalyst on a diatomaceous earth carrier is most suitable. Therefore, the method of the present invention will be described in detail using this catalyst.

The nickel in such catalysts is generally stabilized;
When handled, it is used in the form of a nickel shaped catalyst stabilized on a diatomaceous earth support. This catalyst is packed into a reaction tube that can be heated and cooled, and
The catalyst is activated by treatment at 00° C. for several hours while passing hydrogen through it to obtain a reduced nickel shaped catalyst. A mixed gas of phenol:hydrogen:ammonia in a molar ratio of 1:(5-30):(1-10), preferably 1:(8-20):(1-6) is added to this with a phenol LSV of 0.05-0.2. Preferably cane 0.0? -0
, 15, reaction temperature 100-250℃ preferably Hiro 130-
The reaction is carried out at 180°C. The composition of the resulting reaction solution was 30-70% cyclohexylamine, 5-25% dicyclohexyl 7m, 15-5% cyclohexanol.
%, unreacted phenol is hardly detected by selecting the reaction conditions. High purity cyclohexylamine can be obtained by fractional distillation of this reaction solution. The fractional residue mainly contains dicyclohexylamine and contains small amounts of cyclohexylaniline and other by-products. This can be used as it is or by distillation, mixed with phenol and mixed with hydrogen and ammonia to give a molar ratio (residue of 11 + phenol): hydrogen: ammonia = 1: (5-15): (2-s), gaseous,
A reaction solution containing 6G-80% of cyclohexylamine is obtained by passing it over the diatomaceous earth supported reduced nickel molded catalyst of the present invention at a reaction temperature of 130-180°C. This can be fractionated to obtain highly pure cyclohexylamine.

Therefore, by combining both reactions, it is possible to finally obtain only phenol and dicyclohexylamine, and the yield reaches 97 to 98 units theoretically.

Next, embodiments of the present invention will be described with reference to Examples, but it is noted that the gist of the present invention is not limited by these Examples.

Example! A 2-inch SUS 304 tube is filled with a diatomaceous earth carrier stabilized nickel molded catalyst 350F (volume 330 cc). This outer side is an oil nozzle so that the entire catalyst layer can be heated or cooled. Activation is performed by heating the catalyst layer to 200° C. for 3 hours while passing hydrogen through it.

At this time, distillation of water was completed in about 1 hour, and activation was almost completed. Now lower the temperature to 1160c and add phenol:
Water II's: ammonia = 1:8:2 molar ratio, pheno-xLSV O,1, reaction temperature 165 °C, 10
A time reaction was performed. The obtained reaction solution was fractionally distilled and zpo
As a result of analysis, cyclohexylamine 56.5%,
The contents were 37.3% dicyclohexylamine, 4.7% cyclohexanol, and 2% high boilers. Furthermore, the conversion of phenol was 100%, and only a small amount of cyclohexylaniline was produced.

The purity of cyclohexylamine obtained by further fractional distillation of the above reaction solution was 99.9%.

Examples 2 to 6 After carrying out reactions under various conditions using the catalytic reaction tube of Example 1, the composition of the reaction solution was analyzed by gas chromatography, and the results are shown in the table below.

(Left below) Example 7 After distilling off cyclohexylamine from the reaction solution of Example 1, the residual liquid was dicyclohexylamine, containing tocycyclohexanol as the main component, cyclohexylaniline, and a high-boiling fraction.

As a recipe for recharging this residual liquid, (
Above residual liquid + amount of 7 enol): hydrogen: ammonia = l
:lO:60 molar ratio of mixed gas is LSVo, 1. The composition of the reaction solution obtained by conducting the reaction at a reaction temperature of 165-175°C for 10 hours was 76.2% of cyclohexylamine;
Dicyclohexylamine IS, 3% s 3.5% of high-boiling seafood containing cyclohexylaniline was fractionated and 99.9% of cyclohexylamine was easily distilled off.

Procedural amendment dated June 14, 1980 2. Name of the invention: Method for producing cyclohexylamine 3. Relationship with the person making the amendment Patent applicant Representative: Honshu Kagaku Kogyo Co., Ltd., 1-5-3 Yaesu, Chuo-ku, Tokyo Toshihiko Kasue 4, Agent 4-5 Kojimachi, Chiyoda-ku, Tokyo (102) (・2・
F-1 manga! 6. Contents of amendment (1) The description of "reaction with hydrogen and ammonia" on page 2, lines 16-17 is amended to "reaction with hydrogen and ammonia."

(2) Change the description of “Autocleve” in the bottom two lines of the third page to “
Autoclave” is corrected.

(3) Change the description of “4.7%” in the third line of page 8 to “4.2%”
” he corrected.

that's all

Claims (1)

[Claims] 1. Production of cyclohexylamine, characterized by passing phenol together with hydrogen and ammonia in a gaseous state over a nickel-based shaped catalyst to perform a reductive amination reaction, and fractionating the resulting reaction solution. Law. 2. Phenol; hydrogen: ammonia molar ratio 1; (
5-So): (1-10) preferably 1: (8-20)
: (1 to 6), and the reaction is carried out at a reaction temperature of Zoo to 2521°C, preferably 130 to 180°C.
The method for producing cyclohexylamine described in Section 1. 3. Pass phenol together with hydrogen and ammonia in a gaseous state over a nickel-based shaped catalyst to perform a reductive amination reaction, and then fractionally distill the resulting reaction solution, and distill a distillate whose main component is dicyclohexylyacone, which is a by-product. Cyclohexyl is characterized by distilling off a fraction, mixing it with phenol, passing it in gaseous form over a nickel-based shaped catalyst together with hydrogen and ammonia to perform a reductive amination reaction, and fractionating the resulting reaction liquid. Method for producing amines.