FR2473511A1 - PROCESS FOR PRODUCING POLYAMINES FROM POLYNITRILES - Google Patents

Abstract

The invention relates to a method of manufacturing polyamines from polynitriles using a hydrogenation catalyst in the form of granules. The catalyst used is a granulated cobalt-nickel hydrogenation catalyst usually in the oxide form and practically retaining its integrity character during this hydrogenation without resorting to inorganic or organic stabilizing agents.

Description

247351 1

  The present invention relates to a process for producing polyamines from polynitriles using a hydrogenation catalyst in the form of

of granules.

  It has been found that many hydrogenation catalysts in the form of granules such as cobalt

  or nickel, when used in hydrogenation

  polynitriles to the corresponding polyamines,

  tend to disintegrate. During the reaction of hy-

  In the process of dehydration, the catalyst granules swell and / or disintegrate into fine particles. Due to

  loss of their physical integrity, granules of

  The catalysts lose their usefulness with regard to adequate control of the process, particularly in a continuous process in which variables such as space velocity, etc. must be carefully considered and controlled. In particular, channels may be formed in the catalyst bed, resulting in inadequate contact between the nitrile and the catalyst. In addition, the reactor or its pipelines

  are sometimes clogged with fine particles.

  In US Pat. No. 3,384,666 is disclosed a method of inhibiting disintegration.

  catalyst granules. This process consists essentially of

  It is important to use a base such as sodium or lithium hydroxide or potassium hydroxide. Although the proper use of a caustic stabilizer has been shown to be effective, it has nevertheless been shown to have certain disadvantages thereafter. For example, it has been found that to function effectively, such a process involves the neutralization of the caustic alkali and the separation of the salt by filtration. This obviously requires a long additional operation and

  relatively expensive. It was further discovered that

  The caustic reacts with nitriles containing an additional oxy group so that the desired amine is not obtained. That is, it occurs

  unwanted side reactions.

  Other ways of preserving the integrity of the hydrogenation catalyst granules have been discovered. These involve in some cases the use of an amine stabilizer. However, resorting to such a stabilizer, while avoiding

  the difficulties discussed above concerning the use of

  caustic alkali, always adds to the need for

  of course an additional cost to the overall process given the obligation to use another

chemical additive in catalysis.

  Other solutions to the problem above

  have been proposed in US patents.

  No. 3,427,356; 3,728,284 and 4,007,226.

  The discovery of a particular type of

  catalyst usable for the hydrogenation of polynucleotides

  Triles, which would not undergo disintegration or breakage during catalysis so that the granular form of the catalyst would be retained, and which would not use foreign protective chemicals would therefore represent a considerable advance in the art. According to the invention, the applicant has discovered a process for the hydrogenation of polynitriles,

  polyamines. In its most general aspect, the

  The invention concerns the use of a hydro-

  granular cobalt-zinc generation, usually in oxide form, characterized in that it substantially preserves its character of integrity during this hydrogenation without the use of agents

  mineral or organic stabilizers.

  More specifically, the hydrogenation technique

  for the preparation of polyamines from polynitriles

  triles by the process of the invention involves the hydro-

  polynitrile generation in the presence of a catalyst

  cobalt-zinc hydrogenation in granulated form.

  The hydrogenation reaction itself can be carried out in the presence or absence of a solvent. When a solvent is used, an organic solvent such as an alcohol is preferred. As usable alcohols, mention may be made of methanol, ethanol, isopropanol, t-butanol, n-propyl alcohol and other alcohols,

  especially water miscible alcohols.

  The polynitrile to be treated according to the invention can be chosen from a wide variety

  known materials of this type. Di-

  and tri-nitriles prepared by reacting acrylonitrile

  nitrile with an amine, a polyamine, a polyhydro-

  xymonoamine, polyhydroxy-polyamine, etc.

  that ammonia, methylamine, piperazine, ethyl-

  diamine, monoethanolamine, diethylenetriamine,

  3-aminopropanol, methylethanolamine, aminoethyl-

  thanolamine etc. Other preferred polynitriles are those which additionally contain an oxy group. These oxynitriles typically include, for example, adducts of acrylonitrile to polyols such as ethylene glycol, di- and tri-ethylene glycols, glycerol, trimethylol propane, butane-1,4- diol,

butane-1,3-diol, etc.

  The granulated catalyst used in the invention is a granular cobalt-zinc hydrogenation catalyst which usually consists of cobalt and zinc in molar ratios, expressed as Co and Zn, ranging from 98: 2 to 60: 40. metals are usually under

oxide form.

  The support used can be a support

  inert under treatment conditions such as a refractory support, charcoal, silica, alumina, etc. which is likely to be

  used with the active hydrogenation catalysts.

  The processes for preparing these catalysts on

  ports are well known in the art.

  The hydrogenation reaction itself can

  be performed in a wide range of conditions.

  In general, the polynitrile is hydrogenated in the presence

  a catalyst of the class described at a temperature of

  between about 70.degree. C. and about 2200.degree. C. and at a pressure of about 30.degree. The reaction temperature is preferably 70 to 1500 ° C., the pressure being preferably 35 × 10 5 to 700 × 10 5 Pascal,

  and better still 70 x 105 to 206 x 105 Pascal.

  In a widely preferred embodiment, ammonia is also present during the reaction. Ammonia helps the reaction by promoting better selectivity for the primary amine, and avoids bimolecular coupling leading to the formation of a secondary amine, usually undesired in the reaction. When ammonia is present, its concentration is generally from about 2 to about 20 moles of ammonia per equivalent of nitrile. When

  hydrogen and ammonia are used simultaneously

  nally, the partial pressure of hydrogen is usually

  from about 60 to about 80% of the total pressure.

  The particular space velocity of the hydrogenation reaction (g nitrile / h / cc catalyst) is not critical in the process. However, it is preferred to carry out the hydrogenation reaction at a rate of between about 0.5 and about 5 g.

  total liquid supply / hour / cm 3 of catalyst.

  The hydrogenation reaction can be carried out batchwise, or preferably continuously. For this one appropriate reactors are either a closed autoclave

  for the batch process, ie a tubular reactor

  which can be operated in a continuous manner.

  The desired polyamine can then be

  picked in the middle of the hydrogenation reaction by any known technique, for example

  by distillation. Thus, the polyamine usually needs

  ly be separated from the stabilizer of the amine by distillation when the latter is used in an amount such that it also acts as a solvent

for the hydrogenation reaction.

  It is interesting to note that it is only when polyamines are obtained from polynitriles that the problem of instability of the catalyst during the hydrogenation operation arises. Mononitriles, when hydrogenated, are in no way subject to this disadvantage. Even dinitriles such as adiponitrile or phthalonitrile, when converted to diamines, pose only minimal problems with catalyst stability. But when hydrogenated di- and tri- or tetranitriles obtained by reacting acrylonitriles and compounds reacting with this acrylonitrile such as alcohols and amines, most catalysts such as those of the cobalt type are physically degraded during the course of time. the

hydrogenation reaction.

  In addition, as just mentioned and as will become clearer in the examples below, cobalt catalysts alone, in a fixed bed,

  although they are useful for transforming poly-

  Polyamine nitriles are clearly defective in that the granules or tablets are converted to fines when used during a period of time. significant duration in the hydrogenation process. However, a mixture of cobalt zinc oxides is stable in that it can be stored in granulated form even in the absence of a caustic or an amine

as a stabilizing additive.

  Although the invention has been described with reference to the use of the granular catalysts, it is understood that the term "granule" also means tablets, these physical forms of the cobalt-zinc catalyst being interchangeable

  for use in the invention.

Example I

  A solution of 488 g (1.66 mol) of cobalt nitrate hexahydrate and 36 g (0.12 mol) of zinc nitrate hexahydrate in 2 liters of distilled water is heated to 75 ° C. at 75 ° C. This solution is added slowly and with stirring to 197 g (1.85 mol) of sodium carbonate in 3 liters of distilled water, also at 75 ° C. The addition is complete, the slurry is stirred for an additional hour at 80 ° C. C, then we filter it. The solids collected are washed eight times with two liters of hot distilled water and dried.

  at 110 ° C. and calcined for 2 hours at 400 ° C.

  The mixed oxides of cobalt and zinc (weight 142 g) contain 66.5% Co, 5.1% Zn and 513 ppm sodium. This product is introduced into a glass tube and prereduced at 325 ° C. with hydrogen until no moisture can be detected in the outgoing gases. After cooling the catalyst to room temperature in situ under nitrogen, it is re-oxide

  carefully with oxygen diluted in nitrogen.

  The catalyst of cobalt-zinc oxides stabilized

  with 0.5% graphite, then transform it

  in cylindrical granules 0.32 cm in diameter.

  In a 3-liter flask containing 600 g (10.0 moles) of ethylenediamine, I 855 g is added.

  (35.0 moles) of acrylonitrile at 35-50 C with

  externally. When the addition is complete, the solution is placed in a stirred autoclave with 60 g of a commercial silica-alumina catalyst (Aerocat Silica Alumina TA, America Cyanamid Company) and heated at 160 ° C. for 4 hours. We use this

  mixture of cyanoethylated ethylene diamines as feed

  tation in the experiments described in this example

and in Example II.

  In a small fixed bed reactor, one places

  25 ml of cobalt oxide catalyst granules

  zinc whose preparation has been described above. A liquid feed consisting of weights is passed through the catalyst at a speed of 24 m / h.

  equal amounts of liquid ammonia, methanol and ethylene

  Cyanethylated diamine in the molar ratio of 3.5 / 1.

  Hydrogen (12 l / h) is also introduced into the

  ordinary conditions of temperature and pressure).

  The pressure is maintained at 170 atmospheres and the

  reactor temperature at 1151C. We collect periodically

  samples of liquid product and it is checked whether the reaction is complete by

  nitrile with infra-red. After 53 hours of operation

  The catalyst is removed from the reactor and

  it is found that the appearance of the granules has not changed.

  A sample of the liquid product is passed through a film wiping evaporator and

  it is analyzed by gas chromatography.

  It contains 54% of tris (aminopropyl) ethylenediamine

  and 9% bis (aminopropyl) ethylenediamine.

Example II

  In this experiment, a commercial catalyst prepared from an atomic ratio is used.

  cobalt, copper and chromic oxide 75 23: 2.

  In the same fixed bed reactor as in Example t, 25 ml of 0.32 cm. With the same

- B

  power supply, the same flow of hydrogen, the same pressure

  same temperature and temperature as in Example I, the test

  is completed after 20 hours because the granules of

  lyser completely disintegrated and clogged the reactor.

Example III

  25 ml of granules of 0.22 cm.sup.3 of cobalt-α were introduced into a fixed-bed catalytic reactor with a capacity of 25 ml. trade. -; A reaction product acrylonitrile-ethylenediamine in the molar ratio of 3.5: 1 in solution in methanol-liquid ammonia-polynitrile in the weight ratio 1: 1: 1 is passed over the catalyst with hydrogen. The conversion rate obtained in the hydrogenation is relatively high, except towards the end of the 55 hour test. But the catalyst, removed from the reactor, turns out to be composed of pieces of

  broken tablets, now-unusable.

Example IV

  To a solution of 197 g (1.85 mol) of carbon dioxide

  sodium nate in 3 l of distilled water is added 430 g (1.48 mol) of cobalt nitrate hexahydrate in 2 l of distilled water at 751C. Stirring is provided for 1 hour at this temperature, then filtered and washed 8 times with hot distilled water. The oxides are dried at 110 ° C. and calcined for 2 hours at 400 ° C., which gives 144 g. of product, containing 56.9% Co, 12.8% Zn, 142 ppm sodium. The product is prereduced by hydrogen at 325 ° C., stabilized with oxygen diluted with nitrogen and granulated with 0.5% graphite.The tablets are placed in the fixed bed reactor. of 25 ml and subjected to a continuous test of 101 hours.The nitrile used is prepared by reaction of acrylonitrile

  with ethylenediamine in a molar ratio of 1.5 / 1.

< '73511

  It is passed over the catalyst in a solution composed of equal parts by weight of nitrile, methanol and anhydrous ammonia at a rate of 24 ml.

  hour, accompanied by 12 normal liters / h of hydrogen.

  Gas chromatographic analysis of the product, free of methanol and ammonia, gives 64%

  of bis (aminopropyl) ethylenediamine and 33% of amino

  propyléthylènediamine. The catalyst granules

are physically unchanged.

Example V

  An experiment is carried out here using the commercial nitrile hydrogenation catalyst described in Example II and the same supply of acrylonitrile-ethylenediamine adduct in the ratio 1.5: 1 as in Example IV. Normally, more

  the acrylonitrile-ethylenediamine ratio in the

  If the concentration is low, the catalyst tablets tend to disintegrate. Under the same conditions as in Example IV, the cobalt-copper-chromic oxide catalyst is used for 85 hours, it turns almost completely into a fine slurry at the end

experience.

Example VI

  70 liters of distilled water are heated to 70C

  containing 22.6 g of synthetic calcium silicate.

  The mixture is stirred while slowly adding 244 g of Co (NO 3) 2, 6H 2 O and 16 g of Zn (NO 3) 2, 6H 2 O in 2 liters of distilled water together with 155 g of carbonate.

  of sodium in another two liters of distilled water.

  All solutions are maintained at 70C, the additions being adjusted to maintain the pH of the reaction solution at 7.0. After a digestion period of one hour, the solids are collected by filtration, washed eight times, dried at 1100C and calcined for 1 hour at 400C. The elemental composition of the catalyst before prereduction is as follows: Co 51.3%, Zn 4.1%, Ca 3.7%, Si 4.8% and Na 532 ppm. After prereduction at 325 ° C. and stabilization, granules are prepared using 0.5% graphite. Feeding hydrogenation on bed

  fixed is prepared by reacting 1.68 moles of acrylate

  nitrile per mole of ethylenediamine. The continuous test is

  with the same flows and under the same conditions.

  As in Example I. After 22 hours, gas chromatographic analysis of the product (ammonia and methanol-free) showed the presence of 15% aminopropyl-ethylenediamine, 69% bis. (aminopropyl)

  ethylenediamine and 7.6% tris (aminopropyl) ethylene

  diamine. The test is terminated after 251 hours, the corresponding compositions are then 15%, 69% and 7.3%. Catalyst granules do not form finely divided material, although some

granules are disaggregated.

Claims (9)

  A process for producing a polyamine, in which the corresponding polynitrile is hydrogenated in the presence of a catalyst, characterized in that said catalyst is a cobalt-hydrogenation catalyst. granulated zinc.   2. The process of claim 1, wherein   in that the hydrogenation is carried out in presence of a solvent.   3. Process according to claim 2, characterized   characterized in that the organic solvent is an alcohol.   4. Process according to any one of   Claims 1 to 3, characterized in that   hydrogenation in the liquid phase at a temperature   from 70 to 220 ° C and under a pressure of 30 to 800 atmos-   pheres. 5. Process according to any one of   Claims 1 to 4, characterized in that the hydro-   Generation is carried out in the presence of ammonia.   6. The process of claim 5, wherein   in that the hydrogenation is carried out in   2 to 20 moles of ammonia per molar equivalent of nitrile.   7. Process according to any one of   vendications t to 6, characterized in that the catalyst   comprises cobalt and zinc in oxide form.   8. Process according to any one of   Claims 1 to 7, characterized in that the catalyst   cobalt-zinc has a Co: Zn molar ratio of 98: 2 at 60:40.   9. Process according to any one of   Claims t to B, characterized in that the polynomial   trile is obtained by reaction of acrylonitrile with a active hydrogen compound.