DE2055620B2 - Process for the preparation of 4,4'-diamino-dicyclohexyl-alkanes - Google Patents

Description

The invention relates to a process for the preparation of 4,4'-diamino-dicyclohexyl-alkanes by reacting 4,4'-dihydroxydicyclohexylalkanes with ammonia in the presence of hydrogen and a cobalt-containing amination catalyst applied to a support at increased Temperature, expediently at 150 to 200 'C, and at elevated pressure in the liquid phase, which thereby is characterized in that the amination catalyst is a cobalt, copper and optionally Supported catalyst containing nickel and / or manganese and / or chromium is used.

It can be advantageous to use an amination catalyst which additionally contains 0.1 to 10 percent by weight of an inorganic polyacid and / or the inorganic on which the polyacid is based Has acid. With particular advantage is a supported catalyst with aluminum oxide as Backing material used.

From German patent specification 1272919 it is known that 4,4'-diamino-dicyclohexyl-alkanes can be used by reacting 4,4-dihydroxydicyclohexylalkanes with ammonia in the presence of amination catalysts which contains 90 to 99 percent by weight cobalt, 1 to 10 percent by weight manganese and contain 0.5 to 10 weight percent phosphoric acid. The 4,4'-diamino-dicyclohexyl-alkanes obtained by this process however, do not meet the purity requirements for 4,4'-diamino-dicyclohexyl-alkanes in all cases when using them door the production of polyamides can be put. In addition, the yields according to the Method of the German patent specification are obtained, not fully. Furthermore, the life of the used Catalysts not enough, so that the process of German Patent 1272919 for a continuous Working method is not very suitable.

According to the invention it is now possible to use 4,4'-diaminodicyclohexylalkanes in a yield of 97% of theory and in a purity of 99.9%. The catalysts to be used according to the invention are distinguished by a long service life and are therefore eminently suitable for continuous operation.

4,4'-Dihydroxydieyclohexylalkanes preferred as starting material have the formula

HO

OH

in which R is an alkylene or an alkylidium radical 1 to 6 carbon atoms, preferably ~ t 1 to 4 carbon atoms, labeled, for example

ίο methylene, ethylidene, propylidene, isopropylidene, Butylidene, isobutylidene, pentylidene, jsopentyüden or cyclohexylidene radical. The starting materials and accordingly the end products can be in the cyclohexyl radical substituents still inert, such as lower ones

'5 alkyl groups or lower alkoxy groups, for example each having up to 4 carbon atoms. Suitable compounds are for example 4,4'-dihydroxy - dicyclohexyl - methane, 4,4 '- dihydroxy - dicyclohexyl-propane (l, 3), 4,4-dihydroxy-dicyclohexyl-

ao butane (1,4), 4,4'-dihydroxydicyclohexylpropane- (2,2 |. 4,4 '- dihydroxy - dicyclohexyl - butane - (U), 4,4' - dihydroxy - dicyclohexyl - cyclohexane - (1,1), 4,4 '- dihydroxy - dicyclohexyl - pentane - (1,5), 4,4 '- dihydroxy-3,3 - dimethyldicyclohexyisopropane - (2,2). Special

4,4-Dihydroxydicyclopropane- (2,2) is of technical importance.

In general, 4,4-dihydroxydicyclohexylalkanes are used and ammonia in a molar ratio of 1: 2 to 1:50, preferably 1: 3 to 1:12. Ls is

Although a higher excess of ammonia is also possible, it is more than the molar ratio of 1:50 an excess of ammonia that goes beyond this generally has no advantages. Implementation is in the present carried out by hydrogen, advantageously a hydrogen partial pressure of 5 to 350 at. preferably from 10 to 250 at. The total reaction pressure is usually 60 to 400. preferably 80 to 350 at. In general, reaction temperatures between 120 and 250 ° C., preferably 150 to 220 ° C., in particular 150 to 200 ° C.

The supported catalysts to be used according to the invention generally contain 1 to 30 percent by weight, preferably 5 to 20 percent by weight, cobalt, 0.3 to 10 percent by weight, preferably 1 to 5 percent by weight, copper and optionally 3 to 20 percent by weight, preferably 1 to 15 percent by weight, Nickel and or 0.1 to 5 percent by weight, preferably 0.3 to 2 percent by weight, Manganese and / or 0.1 to 5 weight percent, preferably 0.3 to 2 weight percent, chromium, respectively based on the total catalyst. It is often advantageous to use an amination catalyst the 0.1 to 10 percent by weight of an inorganic polyacid and / or that of the polyacid has underlying inorganic acid. Such inorganic acids that when heated can convert into polyacids are, for example, boric acid, molybdic acid, titanic acid, vanadic acid, Tungstic acid or phosphoric acid. An addition of phosphoric acid is particularly advantageous used. The catalyst preferably contains 0.3 to 5 percent by weight of inorganic Polyacid or that on which the polyacid is based

⁶ S inorganic acid, based on the finished, reduced total catalyst. The stated content relates to the analytically determined content, but does not say anything about the bond status

the acids in the catalyst. It is quite possible that the acids in the catalyst are not free acids, but are wholly or partly in the form of metal salts.

For example, fuller's earth are used as carrier materials. Silica strands, silica gel, aluminum oxide, aluminum hydroxide or aluminum silicates are used. Aluminum oxide is used with particular advantage as the support material. The catalysts are prepared, for example, by impregnating the preformed support material with a solution of the metal salts and, if appropriate, the inorganic acid, it also being possible for the impregnation process to be carried out several times, for example two to three times. The impregnated catalyst is then expediently heated, for example to temperatures from 200 to 900 ^° C. and reduced in the presence of hydrogen before use. It is also possible to apply part of the solution of the metal salts and optionally the inorganic acid to the preformed support material by impregnation and to spray the remainder of the solution onto the subsequently heated catalyst. In the case of the impregnation method, it is advantageous to start from a solution of the metal nitrates. However, it is also possible to prepare the catalyst by precipitating the metal salts onto a support material and subsequently shaping the mixture obtained. Sodium carbonate or sodium hydroxide is expediently used to precipitate the metal salts. However, it is also possible to use other basic agents, such as ammonium carbonate, for the precipitation. The precipitated catalysts are expediently washed neutrally and dried and made carbonate-free by heating. The oxidic mass is then expediently pressed into shaped bodies, for example pills or strands, and heated at elevated temperature, for example at temperatures from 300 to 900 ° C., and then reduced with hydrogen at temperatures generally from 220 to 300 ° C. before use.

The reaction can be carried out in the presence or in the absence of solvents. Inert liquids such. B. N-methylpyrrolidone, liquid ammonia, methyldimethylcyclohexane, Cyclohexane, cyclic ethers such as tetrahydrofuran, dioxane, into consideration. With special Advantageously, the respective starting material is used in dilution with the corresponding end product.

When using a solvent or the end product as a diluent in general the ratio of starting product to end product or solvent 1: 0.5 to 1:10, preferably 1: 1 to 1: 4. surprisingly can it may be advantageous to carry out the reaction in the presence or absence of an organic solvent with the addition of water, expediently in amounts of 1 to 20 percent by weight, based on the starting material, perform. As a rule, the service life of the catalysts is reduced when water is added elevated. When working without any diluent, it is advisable to use a melt of the starting material metered into the reactor c together with liquid ammonia.

The process can be carried out batchwise or continuously. Because of the high The service life of the catalysts is the process especially for continuous operation suitable. The continuous reaction mode is carried out, for example, in such a way that the Head of a vertical high pressure reaction tube which is filled with the reduced catalyst is, a mixture of starting material, ammonia and hydrogen is supplied. In this so-called trickle process expediently the hydrogen separated from the discharge and some of the separated hydrogen Ammonia used again for the implementation. However, the method can also be carried out in this way be that the 4,4'-dihydroxydicyclohexylalkane Ammonia and hydrogen are injected into the reactor from below using the so-called sump operation will.

The most favorable residence time can be given Easily determine reaction conditions such as temperature, pressure and ammonia ratio by means of preliminary experiments. In order to obtain short residence times, the reactor will be loaded with reaction liquid as high as possible. This is advantageously per hour liquid volume carried out 0.5 to 6 times the volume of the catalyst.

The 4,4'-diaminodicyclohexylalkanes obtained by the process according to the invention are suitable Due to their high purity, especially for the production of polyamides. The 4,4'-diamino-dicyclohexyl-alkanes are also used. especially the trans. trans isomers, suitable for the manufacture of fibers.

example 1

50 parts of catalyst containing 18 percent by weight of cobalt, 2.5 percent by weight of copper, 0.7 percent by weight of manganese, 0.5 percent by weight of phosphoric acid (calculated as P ₂ O ₅ ) on aluminum oxide are placed in a reactor 115 mm in diameter and 5200 mm in length filled in as a carrier material. After the reduction with hydrogen at 280 ° C., 1440 parts of 2,2-bis (4-hydroxycyclohexyl) propane and 3000 parts of ammonia are added every hour at the top of the reactor. The reaction pressure is 300 atm and the reaction temperature is 170 C. After the ammonia has been stripped off from the reaction discharge, 1428 parts of reaction product are obtained, 30 parts of which remain in the crude distillate clay. The crude distillate has a 2-cyclohexyl-2- (4-aminocyclohexyl) propane (2.2) content of 1.1% and a 4,4-diamino-cyclohexyl-propane (2.2) content of 98 , 9%, corresponding to a yield of 97.1%. Purification by distillation gives 4,4'-diamino-cyclohexyl-propane (2.2) with a purity of 99.9%, determined by gas chromatography. The pure distillate is a colorless viscous liquid which solidifies in crystalline form at 54 C and having a softening point 54-70 ⁰ C. The pure product has the following isomer distribution:

63.2% trans, trans isomer,
27.6% cis, trans isomer,
9.2% cis ^ is isomer.

If a catalyst is used that contains the same amount of chromium instead of manganese, then you get equally good results.

The catalyst used was prepared as follows: The alumina strands were with the Mixture of the aqueous metal salt solutions to which the phosphoric acid had already been added, soaked twice and the remainder of the metal salt solution in the

Pan sprayed After drying the catalyst at 800 ⁰ C was annealed. The catalyst has a life of up to a Jx & r.

If, on the other hand, the reaction according to Example 1 of German Patent 1272919 is carried out and carried out If the work-up is carried out as in Example 1 of the present application, only a yield of 32.7% is obtained, the purity of the pure product The der in the German patent specification is only 93.9% 1272919 described catalyst can not be used for continuous operation because it disintegrates after 25 to 30 days under the operating conditions used

Example 2

The reaction is carried out as described in Example 1, but using a catalyst containing 10 percent by weight of cobalt, 0.5 percent by weight of copper, 8 percent by weight of nickel and 0.5 percent by weight of phosphoric acid (calculated as P ₂ O ₅ ) on aluminum oxide as Carrier used. The hourly amount of ammonia fed in is 3500 parts, the reaction temperature is 210 ° C. and the total pressure is 300 atm. The discharge from the reaction contains a residue of 3.5%, and gas chromatographic analysis of the crude distillate shows a 2-cyclohexyl-2- {4 content of 2.8% -aminocyclohexyl) -propane- (2.2) and 97.2% 4,4'-diamino-dicyclohexylpropane- (2.2), corresponding to a yield of 94.9%.

Example 3

The procedure is as described in Example 1, except that a catalyst containing 20 percent by weight cobalt 12 percent by weight nickel and 2 percent by weight copper on aluminum oxide is used as the support. 400 parts per hour Ammonia added. The reaction temperature is 220 C, and the reaction pressure is 300 at. Die Crude distillation of the discharge from the reaction gives a residue of 4.3%. The gas chromatographic Analysis of the residue-free distillate showed a content of 3.1% 2-cyclohexyl-2- (4-aminocyclohexyl) -propane- (2.2) and 96.9% 4,4'-diamino-cyclohexyl-propane (2, 2), corresponding to a yield of 92.6%.

Example 4

The procedure is as described in Example 1, except that a catalyst with a content of 10 percent by weight cobalt, 8 percent by weight nickel, 1.5 percent by weight copper, 0.7 percent by weight manganese and 0.5 percent by weight phosphoric acid (calculated as P ₂ O ₅ ) on aluminum oxide is used as a carrier. 4500 parts of ammonia are added per hour. The reaction temperature is 220 ⁰ C and the total pressure at 300 After the crude distillation of the residue, a residue of 2.8% remains behind. The gas chromatographic analysis of the residue-free distillate shows a content of 1.8% 2-Cyclc- hexyl-2- (4-anunocyclohexyl) -propane- (2.2) and 98.2 percent by weight 4,4 '- diamino - dicyclohexyl - propane (2 £), corresponding to a yield of 94.5%.

If you use a catalyst that contains chromium instead of manganese, you get equally good ones Results.

The catalyst was prepared by adding soda solution to a metal salt solution which already contained phosphoric acid and slurried powdered alumina, whereby the metal salts were precipitated and deposited on the alumina. The resulting precipitate was washed free of alkali, separated, dried deformed made by muffles carbonate and heated at 650 ⁰ C

Example 5

A catalyst as prepared in Example 1 but with a content of 0.5 percent by weight

so copper, is in the apparatus described there filled. At a pressure of 300 atm and 170 ° C., 1440 parts per hour are poured over the reduced catalyst 1,3-bis (4-hydroxycyclohexyl) propane and 3000 parts Ammonia passed. After removing the excess) - gen ammonia from the reaction discharge 1424 parts of reaction product obtained. After the crude distillation, a residue of 30 parts remains. The crude distillate was analyzed by gas chromatography. The following were obtained: 3.5% 1-cyclohexyl-3- (4-aminocyclohexyl) -propane and 96.5% 4,4'-diaminocyclohexyl-propane-1,3, corresponding to a yield of 93.5%.

Example 6

As described in Example 4, a catalyst which contains 18 percent by weight cobalt, 0.5 percent by weight copper, 1.5 percent by weight chromium and 0.7 percent by weight phosphoric acid ( _{calculated as P 2} O ₅ ) is produced with aluminum oxide from the carrier material posed. The catalyst will enter the reactor filled. 1272 parts of bis (4-hydroxycyclohexyl) methane and 3000 parts of ammonia are added per hour 175 ° C and 300 at pressure implemented. After the crude distillation, a residue of 4.3% remains. the Gas chromatographic analysis of the crude distillate showed a content of 3.4% cyclohexyl- (4-aminocyclohexyl) -methane and 96.6% 4,4-diamino-dicyclohexyl-methane. The yield was 92.3%.

Example?

1522 parts of 1,4-Bts- (4-hydroxycyclohexyl) butane, 3000 parts of ammonia at 175 ° C. are transferred per hour over a catalyst, as described in Example 6 and 300 at pressure passed. After the crude distillation, a residue of 3.1% remains. Gas chromatographic analysis of the crude distillate showed 3.4% 1 - Ccyclohexyl - 4 - (4 - aminocyclohexyl) - butane and 96.6% 1,4-bis (4-aminocyclohexyl) butane. The yield was 93.5%.

Claims (2)

Patent claims: _1. A process for the preparation of 4,4'-Diaminodicyclohexylalkanen by reacting 4,4'-Dikydroxy-dicydohexylalkanen with ammonia in the presence of hydrogen and a cobalt-containing amination catalyst which is supported on a carrier, at elevated temperature; expediently at 150 to 200 ° C. and at elevated pressure in the liquid phase, characterized in that the amination catalyst used is a supported catalyst containing cobalt, copper and optionally nickel and / or manganese and / or chromium 2. The method according to claim 1, characterized in that the amination catalyst 0.1 to 10% of an inorganic polyacid and / or the inorganic on which the polyacid is based Contains acid.