CH144562A - Process for the catalytic reduction of nitrogenous organic compounds. - Google Patents

Description

  

  Process for the catalytic reduction of nitrogenous organic compounds. The present invention relates to a process for the catalytic reduction of nitrogenous organic compounds by treating these bodies with hydrogen or substances which deliver hydrogen, especially in the liquid phase or the vapor phase, with or without pressure, to the temperature of the place where one operates or at different temperatures.



       Next; the invention, this reduction is carried out in the presence of a contact mass containing at least one body of a microporous structure which results from the formation of a base exchange body, and containing cata.ly constituents tically active.



  Such a body can be either a base exchange body, or a derivative of such a body, obtained for example by leaching the latter with an acid.



  The expression "base exchange body" encompasses all bodies, natural or artificial, which have the property of exchanging their bases for other bases in saline solutions. The hash exchange products which are used in the formation of catalyst compositions which are employed in the process according to the present invention.

   or as a starting material for derivatives to be used thus, may have a high base exchange power or, in many cases, may have a lower base exchange capacity, since the catalytic value of the final compositions is not primarily dependent. I) alement of the degree of base exchange power present.

   In general, the base exchange bodies can be grouped as follows: zeolites with two or multiple constituents, that is to say base exchange bodies containing chemically combined silicon in their nucleus. and non-siliceous base exchange bodies in which all of the silicon is replaced by other suitable acidic or amphoteric metal oxides.

   Two-component zeolites are the reaction products of two types of initial components, i.e. metallates and silicates (using the term metallate in a broad sense which will be defined later in this specification), or metal salts and silicates. It frequently happens that more than one of the members of one type can react, i.e. a silicate can react with more than one metallate or more than one metal salt.

   Multi-component zeolites are the reaction products of at least three types of components, i.e., at least one silicate, at least one metallate and at least one metal salt. (By metallate is meant any salt the anion of which contains a metal; under a metal salt is meant a salt in which the anion does not contain any metal.) Base exchange bodies, both zeolites and exchange bodies not so licious bases, can be associated with diluents ,. preferably in the form of a physically homogeneous structure, as will be described below.

   Either diluted or undiluted base exchange bodies may be present in the contact masses used in the present invention, or their derivatives may be present: but it goes without saying that wherever it is present. question here of base exchange bodies, this expression includes both diluted and undiluted products.



  As already stated, waste exchangers, both zeolites and non-siliceous base exchangers, can also be converted into derivatives which can be used for the formation of the catalytic mass and which have many chemical characteristics and most of the physical characteristics. sics of the base exchange bodies from which they derive. These derivatives can be salt-like bodies, i.e. the reaction products of base exchange bodies with compounds containing anions capable of reacting with the base exchange bodies to form products which have many properties of salts.

   Another class of derivative cases is that of acid-leached base exchange bodies. When subjecting a base exchange body to leaching by acids, in particular dilute mineral acids, the exchangeable bases are first gradually removed. The resulting products contain both the more basic and the more acidic components of the non-exchangeable core of the base exchange body, with or without a portion of the exchangeable bases.

    As the leaching is carried out further, more and more of the relatively positive constituents of the non-exchangeable core are removed and, if the leaching is carried to completion, the leached product contains only the constituents- relatively acidic non-exchangeable nucleus. In the case of zeolites, the end product of long-lasting leaching is a complex silicic acid which has many of the physical properties of the original base exchange body.

    In the remainder of the present description, we will designate. to simplify, base exchange bodies and their derivatives both by acid scavenging and by formation of salt-like bodies under the general term of "permutogenetic" products.



  Catalytically active constituents can be found in the catalyst mass employed in four main forms: They can have been physically mixed with or impregnated with the permutogenetics.

   They may have been incorporated physically, in a homogeneous manner, into the permutogenetilated products, before the latter have been fully formed, in the form of catalytically active diluents or in the form of diluents which have been impregnated. of catalytically active substances. <B> 30 </B> They can be chemically combined in permutogenetic products in a non-exchangeable form,

      that is, they can form part of the non-exchangeable core of the base exchange body present in the final contact mass, or which is transformed into the derivatives: or they can be chemically combined with the bodies exchangers (the bases in the form of catalytically active anions which form with the base exchange body salt-like bodies. 40 They can be combined chemically in an exchangeable form either during the formation of the body. exchange of bases, or by exchange of bases after training.

   Of course, the same or different catalytically active constituents can be present in more than one of the above-described forms and an advantage of the invention is that catalytically active substances can be introduced in a wide variety of ways. forms, which.

    offers a wide choice for catalyst chemists. offers a wide choice to the catarlyst chemist. genetics can vary widely in their chemical characteristics, they all have a similar physical structure which is characterized by greater or lesser microporosity, and high resistance to high temperatures, and

   "in the case of base exchange bodies containing catalytic constituents and which have not been leached with acids to the point of removing catalytically active constituents, these are distributed throughout the carcass of the products in atomic or molecular dispersion , as will be described in more detail below, and this chemical homogeneity is one of the most important advantages of some of the contact masses used in the process of the invention.



  Although the combination of catalytically active substances can be effected with undiluted permutogenetics as well as with diluted permutogenetics, it has been found that contact forms formed from permutogenetic products diluted in a similar fashion. homogeneous are advantageous,

   especially when the diluents are of a physical nature such that they exert a desired influence on the catalytic activity of the contact masses, as when, for example, the diluents are rich in silica, which has been found to be have an aefivant power, when the .diluents, due to a high porosity, a high capillarity or a high surface energy, can be considered as physical catalysts or activators.



  Base exchange cores behave as if they were extremely high molecular weight products, since catalytically active constituents can be introduced either into the non-exchangeable nucleus or in the form (the exchangeable bases in virtually any desired proportion and the ordinary law of chemical combination proportions.

   which in compounds of low molecular weight restricts the proportions in which constituents can be incorporated chemically, appears to be without force, which makes it reasonable to assume that the molecular weight is so high that it completely obscures \ effect of law. It is. of course, possible that the base exchange bodies. or some of them, may be solid solutions of several compounds of lower molecular weight, related to each other. It was not possible until. present, to decide definitively.

         this question, because base exchangers are not easy to analyze chemically as to their structure. The invention is, of course, not limited to any theory: but, whatever the fundamental reasons, the fact that catalytically active constituents can be chemically introduced in any desired proportions is of enormous importance to the invention. catalytic chemist and allows it to produce an almost unlimited number of catalysts or masses (finely and gradually contact;

   dosed for the reaction envisaged and in all cases the contact masses produced are highly effective, due to the physical structure of the permutogenetic products contained therein and the wide limits of homogeneous dilution of catalytically active molecules or atoms. with resulting smoothness and smoothness of action.



  In addition to the important characteristics dor7t permutogenetic products endow the contact masses used in the process according to the invention, it has been found that it is frequently desirable to regulate the action of these contact masses and this can be done by combining permutogenetic products, or by incorporating or forming therein compounds of alkali metals, alkaline earth metals and strongly basic earth metals.

   These compounds appear to slow or soften the catalytic reaction and will be referred to throughout this specification under the name of regulators. The regulators can be non-alkaline, weakly alkaline, or strongly alkaline, depending on the nature of the catalytically active constituents used.

   A great advantage is that in the normal formation of base exchange bodies, oxides of alkali forming metals are present as exchangeable bases and, when used without acid treatment or acid treatment, they form. regulators which are combined in, or associated with, the resulting permutogenes in an extremely fine-divided state in which these regulators are particularly active. Thus, base exchange bodies containing alkali metals can be regarded as complex regulators.

      In addition to the use of regulators, it has been found that it is possible, in many cases, to increase the action of these and the total efficiency of the contact masses by associating with them, or by chemically combining therein, elements or radicals or groups which are caialytically active, but do not possess any specific catalytic activity for the reaction envisaged. Such catalysts, or catalytic constituents which are not specific catalysts for the reaction in which they are used, under the reaction conditions with which one is dealing,

   will be referred to throughout this specification as auxiliary catalyst bodies, or regulation promoters, as they appear to enhance the dosing effect which regulators can perform. Such auxiliary catalysts can be present there. where there are no regulators.



  The enormous range of chemical groups which can be combined in, or with, or incorporated into permutogenetics allows a wide choice of auxiliary catalyst bodies as well as specific catalysts and allows their association with the masses of. contact in an extremely homogeneous and catalytically effective form.

   Thus, many base exchange bodies or their derivatives can constitute at the same time catalysts, regulators and complex auxiliary catalysts, because all the elements playing these different roles can be present in the same chemical compound and participate in the advantages. arising from its physical structure and desirable chemical properties.

   Of course, both regulatory bodies and auxiliary catalyst bodies can be mixed partially or completely with permutogenetics and a single regulatory body or a single auxiliary catalyst can be present in part in physical mixture and in part in chemical combination, as will be understood. clearly the informed base exchange chemist.



  The base exchange bodies which form the important constituents in 1 <r. contemplated contact mass can be prepared in any of the well known ways. Thus, for example, two-component zeolites can be prepared by wet processes in which the metal constituents or the metal salt constituents, including:

      some or all may be catalytically active, are reacted with soluble silicates to form zeolites of the alumino silicates, or double aluminum silicates;

    or the constituents can be melted, preferably in the presence of fluxes. It goes without saying that the expression metallate contains not only the alkaline solutions of oxy or amphoteric metal hydroxides, but also salts, of metallic acids, of alkali metals, such as the oxacids of metals of the fifth and sixth groups. which, in at least one of the oxidation stages, are not strictly speaking amphoteric;

    but which are products capable of reacting with silicates to form zeo lithes, or with other constituents to form non-siliceous base exchange bodies. Throughout this specification, we will adhere strictly to this somewhat more general definition of metallates. In the formation of two-component zeolites by the wet process, the final reaction product should be alkaline with respect to sunflower and, for products with a high base exchange power,

   it must be neutral or alkaline with respect to phenolphthalein. In order to produce base exchange bodies to be used in the preparation of contact masses for carrying out the process according to the present invention, it is sometimes unnecessary to provide a high base exchange power and, for many reasons. Uses, zeolites formed under conditions where a final reaction results which is acidic with respect to phenolphthalein, but alkaline with respect to sunflower have an advantage.

   It is not clear whether the products obtained under such conditions are homogeneous chemical compounds, although in many ways they behave as if they were. There is, however, reason to believe that, in at least some cases, mixtures of base-exchange polysilicates and non-base-exchange polysilicates can be produced. For the purposes of the present description, a product will be considered as a base exchange product if it has a base exchange power, however low it may be.



  It is desirable, for many needs and in particular when two-component zeolites, with a high base exchange capacity, are necessary, to add the relatively acid components, for example the metal salts in the case of silicates of the silicate type. aluminum double, with relatively more alkaline constituents such as soluble silicates, for example. By these means, continuous alkalinity is ensured and this procedure can be considered preferable in most cases.



  Multi-component zeolites can be prepared by any of the foregoing processes using at least three types of components, i.e. at least one metallate, at least one metal salt and at least one metal salt. minus a soluble silicate. In the case of multi-component zeolites. as in the case of two-component zeolites, the conditions of alkalinity must be observed and for many uses it is advantageous to add the relatively acidic components to the relatively alkaline components in order to ensure a reaction. alkaline continues. The multi-component zeolites produced vary in nature depending on the proportion of the different reactive components.

   Thus, where metallates and silicates predominate over metal salts, the resulting products resemble two-component zeolites of the aluminum silicate type. If the metal salts and silicates predominate over the metallates, the product resembles the two-component zeolites of the double aluminum silicate type and, ultimately, if the metallates and metal salts predominate over the silicates, the resulting product looks like more or less to non-siliceous base exchange bodies.

   It is clear that there is no clear line of demarcation between the three types of multiple component zeolites and that one merges into the other as the proportions of the different components vary. An advantage of multicomponent zeolites over bicomponent zeolites is that the choice of catalytically active constituents is wider, since some catalytically active elements or groups can only be incorporated in the form of metallates and others only as metallates. the form of metal salts.

   In a multi-component zeolite, each catalytically active group can be incorporated in the form in which it is best usable.



  Non-silicate base exchange bodies can be produced by the general methods described above; but, instead of producing reactions between silicates and other metal oxide constituents, two or more oxymetallic compounds can be reacted of which, in general, at least one will be a metallate and at least one. a metal salt; or, in some cases, it is possible to produce a reaction between two different metallates in which one of the negative radicals is more acidic than the other.

   It is possible to produce non-siliceous base exchange bodies, in which several metal oxides are present. It is also possible to produce non-siliceous base exchange bodies in which only one metal is present. Thus, for example, certain metals may be of a sufficiently amphoteric nature to form both metallates and metal salts which are capable of reacting with each other to produce base exchange bodies.



  A special process for the production of non-siliceous base exchange bodies is to gradually neutralize strongly alkaline salts of the oxacids of metal elements of the fifth and sixth groups in oxidation stages in which they are sufficiently amphoteric. Neutralization of other strongly alkaline metallates can also effect formation of non-siliceous base exchange bodies. The reverse process, whereby non-alkaline salts of suitable metals are gradually treated with alkali until the reaction is sufficiently alkaline to allow the formation of base exchange bodies, can also be applied.



  Many metals are only able to enter the formation of the base exchanger at certain stages of oxidation and it is sometimes necessary to introduce these metals in a stage of oxidation different from that desired in the final base exchange body, the change in oxidation stage preferably being effected during the formation of the base exchange body: Certain other elements can be incorporated in the form of complex compounds of the most varied types, such as example that ammoniacal groups, etc.



  In addition to the artificial base exchange bodies briefly described above, use may be made of natural base exchange bodies such as nepheline, leucite, feldspar, etc.



  The most advantageous contact mass for many reactions contains base exchange bodies in which diluents are homogeneously incorporated into the base exchange bodies before the formation of the latter or, at least, before the exchange body. of bases was taken after training. Many diluents, both inert and regulating, activating, or catalytically active, can be used.

   Some thinners may be mentioned briefly: hieselbuhrs of all kinds, in particular natural or treated cellite earth, siliceous powders of various types, natural or artificial powder of rocks, stones, tuffs, trass, lava and similar volcanic products. which are frequently very porous, green sand, glauconite or its derivative washed with acid, glaueosil, pulverized slag wool, cements, sand, gel (silica, pulverized pottery, fuller's earth, talc, glass powder, pumice stone powder, asbestos, graphite, activated carbon, quartz powder,

   powdered mineral worms rich in quartz, metal powders and powders of metal alloys, salts of oxymetallic acids such as tungstates, vanadates, chromates, uranates, manganates, cerates, molybdates, etc. in particular copper salts thereof, silicates such as copper silicate, iron silicate, nickel silicate, cobalt silicate, aluminum silicate, titanium silicate, minerals or ores, especially those loaves of copper, etc.

   Finely divided diluents have a great advantage, especially when the average particle size is less than FO microns, in which case the diluents have a high surface energy which increases the adsorption and absorption capacity of the contact mass. , the diffusion speed and the. porosity.

   These finely divided diluents can be regarded as physical catalysts or activators. <B> Oïl </B> can also finely divide dilute permutogenes and use them as part or all of the diluents of other base exchange bodies. .



  The following nine methods are the most efficient for introducing diluents; but any other suitable method can be used: The diluents can be mixed with one or more liquid constituents of the base exchange bodies to be formed, when the latter are prepared by the wet route.



  Components, either catalytically active or otherwise, can be precipitated or impregnated in diluents, which are then incorporated into the base exchange bodies by any suitable incorporation methods.



       3 () The diluents can be mixed with base exchange bodies, when the latter are still in the form of jellies, by kneading or stirring, in which case the base exchange jelly behaves like an adhesive. The homogeneity and uniformity of the distribution of the diluents is, of course, not quite as great by this method as by method 1; but, for many catalytic reductions involving nitrogenous organic compounds, extreme uniformity is not essential.



  Diluents can be formed during the formation of base exchange bodies by mixing suitable compounds with the constituents of the base exchange bodies so that the diluent particles are precipitated during formation. Protective colloids can be added to prevent coagulation of the diluent particles before the base exchange bodies have set sufficiently.



  <B> 50 </B> Compounds which react with some of the constituents of the base exchange bodies can be added to produce diluents; for example, salts of the acids of metals of the fifth and sixth groups may be added in sufficient excess to react with constituents of the base exchange body to form insoluble diluents, for example with heavy metal oxides .



  Preformed base exchange bodies, diluted or undiluted, artificial or natural, can be impregnated with true or colloidal solutions of catalytically effective constituents and then dried.



  A preformed, diluted or undiluted base exchange body can be impregnated with several solutions which react therein to precipitate any desired diluents.



  Soluble diluent compounds can be added to the constituents forming a base exchange body which, after formation, hold the compounds in solution and which are dried without washing, or which are treated to precipitate the compounds.



  <B> 90 </B> Base exchangers, natural or artificial, diluted or undiluted, or their derivatives, can be impregnated with solutions of the desired compounds which are subsequently precipitated by means of reactive gases.



  The nucleus, or non-exchangeable portion, of the molecules of base exchange bodies is ordinarily considered to consist of two types of oxides, namely: relatively basic metal oxides, usually amphoteric, and relatively acidic oxides such as SiO2, certain amphoteric metal oxides and certain metal oxides which have a distinctly acidic character.

   The no @, = au behaves like a simple anion: it is of key advantage to consider the two portions of the nucleus as the basic and acidic portions, naturally bearing in mind that the nucleus behaves like a single group. The metallic compounds which are capable of forming the basic portion of the nucleus are those of the following metals: copper, silver, gold, bis muth, beryllium, zinc, cadmium, boron, aluminum, certain rare earths, titanium, zirconium , tin, lead, thorium, niobium, anti monk, tantalum, chromium, molybdenum, tungs tene, uranium, vanadium, manganese, iron, nickel, cobalt, platinum, palladium.

   Compounds of these elements can be introduced, individually or as a mixture, in any desired proportions and these compounds can be in the form of single or complex ions. It goes without saying that some of the elements, at certain oxidation stages, can be introduced either as metallates or as metal salts. Others can only be introduced in one of the forms and still others can be introduced in an oxidation stage other than that desired in the final base exchange body, or in the form of compounds. com plexes. Among the complex ionogens are ammonia, hydrocyanic acid, oxalic acid, formic acid, tartaric acid, citric acid, glycerin, etc.



  Many metals are specific catalysts; others are regulators and still others are favorers for the effect of the latter. Of course, the condition of an element as a catalyst or regulation promoter will vary with the particular reduction reaction for which the final contact mass is to be used.

    and the choice of catalysts and regulating promoters as well as the proportions will be determined by the particular catalytic reduction of the particular nitrous organic compound to which the contact mass is to be applied.



  Examples of constituents forming the relatively acidic portion of the exchanging nucleus are alkali metal silicates, which are soluble in alkali, and alkali metal salts of acids such than those of boron, phosphorus, nitrogen, tin, titanium, vanadium, tungsten, chromium, niobium, tantalum, uranium, antimony, manganese, etc.



  The exchangeable bases of the base exchange bodies can be substituted by exchange of bases e1; the elements which can be introduced singly or as a mixture, by exchange of bases, are the following: copper, silver, gold, ammonia, beryllium, calcium, manganese, cesium, potassium, sodium, zinc, strontium, cadmium, barium, lead, aluminum, scandium, titanium, zirconium. tin, antimony, thorium, vanadium, lithium, rubidium, thallium, bismuth, chromium, uranium, manganese, iron, cobalt, nickel, ruthenium, palladium, platinum and cerium.



  Depending on the case, the exchangeable bases introduced can be specific catalysts; they can be regulators, or they can be promoters for them. They can be introduced as simple ions or as complex ions and they can increase the catalytic activity of the final contact mass, improve its physical structure or produce both effects.



  As described above, base exchange bodies can be reacted with compounds containing acidic radials capable of forming salt-like bodies with them. The radicals can be present in the form of simple acidic radicals, polyacid radicals, or complex acidic radicals and include radicals containing the following elements: chromium, vanadium, tungsten, uranium, molybdenum, manganese, tantalum, nio bium, antimony, selenium, tellurium, phosphorus, bismuth, tin, chlorine, platinum, boron. Among the complex radicals are ferro- and ferricyanogens, some ammoniacal groups, etc.

   The amount of acid radicals caused to unite with the base exchange bodies can be varied to form salt-like bodies so that the end products may have the character of acidic, neutral or basic salts.



  Diluted or undiluted base exchange bodies can be treated with acids such as mineral acids, for example: 2-10% sulfuric, hydrochloric or nitrogen acids, to remove some or all of the exchangeable bases, or also part or all of the basic portion of the core.



  In the case of zeolites, partial acid leaching, which leaves part or all of the basic portion of the nucleus, or even part of the exchangeable bases, does not affect the function of the zeolites as catalysts when they contain catalytically active elements in the basic portion of the nucleus, or in some cases even exchangeable bases.



  Non-silicate base exchange bodies, whether partially or completely leached, can contain analytically active constituents, and many important catalysts for the hydrogenation of nitrogenous organic compounds are thus obtained. This is particularly the case for. reactions where a relatively alkali-free contact mass is required for best results and where the alkaline content of a contact mass containing a base exchange body may be too high for excellent results.



  Diluted or undiluted base exchange bodies can also be applied, in the form of films, to massive carrier granules, or else these granules can be impregnated with them. These massive carriers can be inert, activating or themselves be catalysts. For example, certain metal alloys, certain minerals and especially copper-bearing minerals, fall within this class.

   Aluminum or copper alloy granules play a further advantageous role in that their relatively high thermal conductivity tends to prevent local overheating in strongly exothermic reductions of organic nitrogen compounds, which has a positive effect. considerable importance for obtaining good yields.



  The contemplated contact mass can be used for all types of reduction, liquid phase and vapor phase, of nitrogenous organic compounds. They are particularly suitable for the reduction of aromatic nitro compounds.

   Among the specific reactions, there may be mentioned as a few examples: the reduction of aromatic nitro compounds in the azoxy-azohydrazo- and amino compounds, as well as the hydrogenation of the amine compounds produced. Thus, for example, it is possible, under suitable reaction conditions, to reduce nitrobenzine from 1 = i to azoxvbenzine,

          rizobenzine, hydrazobenzine or aniline and hydrogenated amines such as, cyclohexylarniale. dievclohexvlamine and cyclohexvlaniline. -De- substituted nitro aromatics can be similarly reduced. Examples of such products are. nitrotoluols, nitroxylols. substituted nitrobenzol, etc.

   Other important nitro flavor compounds are α-nitronaphthalin which can easily be reduced, by means of the present invention, to α-naphthylamine.



  Nitro aliphatic compounds can also be reduced to the corresponding amine. Thus, for example, alkyl nitrites can be reduced to corresponding amines and nitromethane can be reduced to methvlamin.



  It is also possible, for example, to carry out the key hydrogenation of pyridine to pipPridine, of pyrrol to pyrrolidine, of quinolinc to tetrahydroquinoline. Certain nitrogen compounds may contain both nitro groups and nitrogen in a different form and may be suitably reduced or hydrogenated by the contact masses of the present invention. So, for example, the:

  3-nitropyridine can be reduced to 3-aminopyridine, etc.



  The reactions, especially in the vapor phase, can be carried out with reducing gases such as hydrogen, gases containing hydrogen. such as water gas, carbon monoxide with oii without vapor, ete. In the case of gas z water and carbon monoxide, <B> CO </B> is partially oxidized to CO2. It is desirable to maintain the oxidized in vapor phase reactions sufficiently high so that the nitrogen compounds do not condense and the wide choice of finely dosed catalysts afforded by the invention is of great importance to the.

   reduction of organic nitrogen compounds which, because of their high vaporization temperature, must be reduced under relatively uniform reaction conditions because it is well known that high temperatures tend to upset the reaction equilibrium . The reaction can take place at atmospheric pressure or at. a pressure higher or lower than this. Preferably, use is made at pressures greater than. atmospheric pressure in the presence of vapor.



  The vapor phase reduction of nitro compounds to the corresponding amines is preferably carried out at temperatures between <B> 180 </B> and 250 ° C; but by the choice of a suitable catalyst and. when a large excess of hydrogen is used, the reactions can also be carried out at much higher temperatures, for example 300--350 C.

   In many cases, with the contemplated contact masses, yields of 98% of theoretical yield can be obtained, and even better still, and the purity of the reaction products is extremely high in most cases. Some contact masses very effectively withstand high temperature and possess high resistance to recrystallization and deterioration and the longevity of the contact masses is very long, which is an important feature in reduction processes.

   In some cases, especially with highly diluted contact masses, the mechanical strength may be somewhat lacking and in such cases it may be advisable to wash the contact mass after drying with a soluble silicate. to perform superficial silicification.



  Many reactions can be carried out by a single pass on the contact mass; but other reactions preferably take place in a circulatory process in which the gases are continuously recirculated. with suitable means for removing the reaction products. In such circulatory processes, very large excess of hydrogen can be used and these are beneficial. The excess of hydrogen may in many cases be ten times or more the theoretical amount required.



  Although an enormous variety of contact masses can be prepared containing most of the various catalysts, the most effective contact masses for many reactions, especially the reduction of nitrated aromatics to the corresponding amines, are those which contain one or more of the elements copper, tin, silver, nickel, iron, cobalt, or zinc. These contact masses are especially effective when they contain regulatory enhancers such as dehydrogenation catalysts, water-decomposing catalysts or oxidation catalysts.



       180-250 C is a suitable temperature for the reduction of aromatic nitro compounds without hydrogenation of the aromatic nucleus, especially when very effective contact masses which contain silver, copper or tin are used. as the main catalytic reduction constituents. In some cases, use can be made at higher temperatures, up to about 3s0 C, especially when a large excess of reducing gases is used.

    In this way, an excellent yield of very pure aniline can be obtained from nitrobenzine, the products containing only traces of azobenzine which can easily be separated from the aniline by distillation. Under similar conditions, nitrotolu.ols can also be converted to toluidine, #. with good yields, at 250-350 C, the product being of excellent purity.

   Halogenated substituted nitro compounds can also be easily reduced with the same type of contact masses, as well as polynitro compounds such as di-nitrobenzines, dinitrotoluols, dinitrophenols, etc. When the contact masses contain iron, nickel, or cobalt as the main effective reducing catalytic constituents, the reductions must be carried out at a somewhat lower temperature to prevent the formation of a large amount of by-products.



  Advantageously, the envisaged contact masses are subjected to a preliminary treatment with reducing gases in order to increase their reactivity for the reduction of nitrogenous organic compounds. This pretreatment and the catalytic reductions themselves produce secondary chemical changes in the composition of the contact masses, particularly on the surface, although usually the beneficial physical structure appears to remain unaffected. For this reason,

   it will be a question of the contact masses as of the moment when they are freshly prepared, as it is the habit in the. Lytic cat chemical nomenclature. An advantage of the contact masses of the invention is that, in many cases, it is possible to have a much higher load per volume of contact mass than in the case of contact masses which have been used up to the present time. here.

   The normal load is about 50 to 80 parts by weight per 1000 part., Corresponding by volume, per day; however, with many contact material compositions of the present invention, including some described in the specific examples which follow, an overload of up to <B> 50% </B> can be used. and moreover without affecting the purity of the above products; without seriously reducing the longevity of the contact masses.

   These large increases in efficiency can be achieved with particular ease in converters which do not allow heat buildup, to any appreciable degree, in the contact layers. Examples of such converters are those of the automatic heat exchange type.



  When converters with effective temperature control are used, concurrently with recirculation, the reducing gas flow can be kept at a very moderate level. So, for example, in many cases a circulation of 1 to 3 times the contact mass per hour is quite sufficient. However, when the loads are increased, the flow must be properly regulated to prevent heat build-up which could reverse the action of the catalysts.



  When the envisaged contact masses finally show a deterioration due to an alteration due to the presence of harmful products in the nitrogenous organic compounds or in the reducing gases employed. they can be regenerated directly in the converters by treating them with gases containing oxygen by first gradually increasing the latter, the temperature being maintained at 250-450 C. After uniform oxidation of the contact mass , it can be reduced with reducing gases at 220-320 ° C.



  The reduction of many nitrogenous organic compounds, and in particular the reduction of nitro aromatic compounds, may result in products contaminated with certain by-products which decrease their value. The production of by-products can be avoided to a large extent by making use of a very high ratio of reducing gas to reduced compound. Thus, this ratio can be about 10: 1, although, of course, higher or lower ratios are disadvantageous. For all sensitive reactions, especially when the contact mass of which.

    use is very active, ratios of up to 1 part compound to 30 to 50 parts reducing gas may be desirable, particularly in circulatory processes.



  Although many face contact masses are of particular importance for vapor phase hydrogenations of nitrogenous organic compounds with or without pressure, many of these masses are strongly active in liquid phase reduction, with or without pressure, or in liquid phase reduction. reductions which take place in suspension. The following examples serve to illustrate the process according to the invention and at the same time give advantageous methods for the manufacture of a number of typical contact masses.



       Example <I> 1: </I> 910 to 340 parts of SiO2 are diluted with 4 to 6 volumes of water in the form of a commercial solution of sodium-based water glass and carefully added. am moniac until the cloudiness which forms first disappears. 996 to 300 parts of copper nitrate are dissolved with 6 molecules of water in enough water to produce a <B> 10% </B> solution and enough concentrated ammonia is added so that the precipitate which forms first re-dissolves in. giving a dark blue solution.

    The blue solution is then poured into the water glass solution, stirred and heated to 60-80 ° C. The reaction mixture soon solidifies into a jelly which, if continued to stir, turns to ag. granular aggregates. The precipitate, which is light blue, is pressed, dried and broken into fragments of greenish blue color and having a conchoidal break.

   When treated with hot water, the framnients break up into small granules which have base exchange properties and constitute a sodium and copper zeolite, or a sodium, ammonium and sodium zeolite. copper in which copper is present in an unchangeable form and cannot be easily dissolved by ammonia.



  The granules are treated, preferably at 250-320 ° C., with gases containing hydrogen, and the reduced catalyst thus obtained gives excellent results in the reduction of nitro aromatic compounds. Thus, for example, nitrobenzine is easily reduced to aniline, using hydrogen, or purified water gas, at temperatures between 180 and 240 C. The process is preferably practiced. as a circulatory process and heavier loads than the normal load can be used, since the catalyst is very concentrated.

   The normal charge is around 50 to. 80 parts by weight of ni-trobenzine per 1000 contact mass volumes per day; but one can overload the key catalyst 40 to 6017o without significantly affecting the purity of the product and without seriously curtailing. the effective longevity of the contact mass.

   When overloading the contact mass, the percentage of reducing gases will preferably be higher than normal, 20 to 40 times the. Theoretically necessary quantity of hydrogen, or corresponding quantities of other reducing gases are very favorable and the velocity of the, -, -,). z must be such that the contact volume is increased from 6 to 8 faith.

       Î), the time in order to avoid an accumulation (heat in any part of the contact plate. The best results are obtained by making use of particular types of converters, for example those provided with heat exchanger devices. automatic flooded in the contact strength, which do not allow heat accumulation.



  Diluents can be introduced into the contact mass during training without any reduction in its effectiveness or its capacity. Examples of such diluents are hieselguhr, pumice powder, charcoal powder. , finely divided pyroliisite, powders of natural or artificial zeolites, diluted or undissolved, powders of rocks, tuffs, trass of volcanic origin, green sand, glaucosil, which is the residue washed with water. green sand acid, silica gel, powdered pottery and the like.

   These diluents can be stirred in the water glass solution or the cuprammonium nitrate solution; or, if desired, they can be incorporated into the melanin solutions (.yeas. or during the formation of the base er.ha.nger body. Another mode of introduction is to knead the diluents in the exchange jelly. bases after the latter has been formed.



  The key contact mass can be adjusted or metered, as described above, by introducing compounds of aluminum, thorium and titanium. These compounds can be introduced by exchange of bases, replacing part of the sodium, - and they can be introduced individually or as a mixture. Thus, for example, copper zeolite, diluted or undiluted, can be treated with a 5 to 10 <B> (</B> solution of thorium nitrate which is allowed to trickle over the zeolite while the latter is on a filter.



  Copper zeolites, dosed with regulators as described above, when used under the above reaction conditions, give very pure aniline, between 98 and <B> 99% </B>. purity, and containing only traces of azoben-2ine as an impurity. The latter can easily be removed by a single distillation. When we. uses a circulatory process, the pc-yields can in fact be considered theoretical.



       Example <I> 2: </I> The following four solutions are prepared: 1o 75 to 80 parts of SiO2 are mixed, in the form of an ammoniacal solution of water glass of a strength double the normal, with sufficient of pumice stone pulverized to form a thin paste.



  15 parts of Al 2 Og, as a hydroxide containing 3 molecules of water, are obtained by precipitating a corresponding amount from a solution of aluminum nitrate with ammonia and dissolving hydrate in sodium hydroxide solution of twice the normal strength to form sodium aluminate.



       3o 60 parts of copper nitrate containing 6 molecules of water, or a corresponding amount of solutions of other copper compounds, are dissolved in a <B> 10% </B> ammonia solution to form a aqueous solution of the cuprammonium compound. 3 to 4 parts of VZO are precipitated;

       freshly Z) repaired by reducing, using gas containing SO -, a corresponding quantity of V20 'suspended in acidulated water, at the boiling temperature, washing and dissolving in a KOH solution of ten times the normal strength to form the corresponding potassium vanadite. An equivalent amount of potassium cliromite can be substituted for the vanadite; or one can use a mixture of the two.



  'Solutions 2 and 4 are poured into the suspension 1, and the mixture is heated to 60-70 ° C., with vigorous stirring, after which it is introduced in a running stream. solution 3. The reaction product soon turns into a green-blue jelly and the yield can be increased by the careful addition of? to 3 c 'of hydrochloric acid. The gelatinous precipitate is poured in. it is dried below 100 ° C., then it is hydrated by running water over it.

   The body obtained possesses good exchange powers. bases and can be used for the catalytic reduction of organic compounds. Thus, it is possible to pass the vapors containing 3-nitropyridine, mixed with a hydrogen gas, over the contact mass previously treated with gai containing hydrogen fi 220-230 C. The reaction temperature should be about 200-250 C and good yields of high purity 3-aminopyridine (,. The product is crystalline and has a melting point of about 63 C.

      <I> Example 3: </I> 1o 22 parts of freshly precipitated Cn0 are impregnated with 60 to 80 parts of broken cellite bricks. The impregnation can be carried out advantageously by impregnating the debris of cellite bricks with a 10% solution of copper nitrate, then by precipitating the oxide with a solution of sodium hydroxide of a strength double of 1. <r normal, shaking vigorously. We filter everything and wash it until it is free of alkali.



  <B> 90 </B> 7.75 parts of WO 'dang. "A solution of sodium hydroxide of twice the normal strength are dissolved to form sodium tungstate.



  <B> 30 </B> 3.4 parts of A1 = 0 '\, in the form of freshly precipitated aluminum hydrate, are dissolved in normal sodium hydrate solution to form aluminum sodium nate. The aluminate and tungstate solutions are then poured together, with vigorous stirring, then the diluent impregnated with copper oxide is added.

   After thorough mixing, the dilute base exchange body is precipitated which is formed by the addition, a normal solution of nitrogen acid which is added gradually, taking care that the final reaction product is alkaline or neutral to with respect to phenolphthalein. The reaction mixture is stripped from the mother liquor by suction, washed with about 200 parts of water and then dried at temperatures preferably below 100 ° C.

    The precipitate, dried, is broken up into small fragments suitable for filling a converter with automatic heat exchanger elements, as discussed in Example 1., then carefully reduced in a stream of constant gas. nant hydrogen, at 250-300 C. The contact mass thus obtained is well suited for the catalytic reduction of nitro aromatic compounds.

   Thus, for example, vapors of nitrotoluols or nitroxylols, when they are passed over the contact mass with a strong excess of reducing gases, such as hydrogen, in a circulating process, at 200-250 C, are reduced in the corresponding toluidines and xylidines. Preferably, the amount of hydrogen should be about ten times the theoretical amount needed to effect the reduction (the nitro group.

   The catalytically effective component is introduced in the form of the diluent and the combination results in a well-dosed contact mass; for these particular uses. The encrusted copper oxide can be substituted with tin oxide or silver oxide, or a mixture of two or three of these constituents can be used. In some cases, small amounts of cobalt and nickel oxides can be added as diluents.



  The non-siliceous base exchange body may contain other components such as V20 ", V20 ', Mo03, and the alumipium-containing component may be substituted, in part or in whole, by other amphoteric metal oxides such as the oxides. of cadmium and zinc The contact masses produced are also very effective.

      <I> Example </I> t: A tin or copper base exchanger containing tin or copper in a non-exchangeable form is prepared as follows: Diluted with -1 to 5 times their weight in water 40 to 50 parts of <B> S10 \ </B> in the form of a commercial water glass solution. 75 parts of aluminum nitrate containing 9 molecules of water are precipitated with a 20% ammonia solution and the resulting aluminum hydrate is converted into the corresponding sodium aluminate by means of a solution of sodium hydrate of double the normal strength.

   50 parts of pumice powder are incorporated into the water glass solution, then the aluminate is added. A 20% solution is prepared; of SnCl2 containing 2 molecules of water and added to the aluminate-soluble glass mixture until the reaction is slightly al caline with respect to phenolphthalein. A jelly forms which is filtered and washed. The SnCl \ solution can be replaced by a corresponding amount of a 20% copper nitrate solution.



  The product. obtained is a so-called three-component zeolite which contains, in non-exchangeable form, aluminum and tin, or aluminum and copper, and constitutes an excellent contact mass for the catalytic reduction of aromatic compounds nitrated to corresponding amines.

   The efficiency of the contact mass can be further improved by vacuuming and washing until the washing water gives nothing in the chlorine test, then incorporating therein the non-siliceous base exchange body. as diluent: 10.2 parts of Al20 ', in the form of freshly precipitated aluminum hydrate, are dissolved in a solution containing 40 parts of 100% KOH in 200 parts of water.

   The zeolite body described above is incorporated into this solution, then to the aluminate mixture is added, with vigorous stirring, a 10-fold aqueous solution containing 44.4 parts of aluminum sulphate with 18 molecules of water. The aluminum sulphate can be replaced, if desired, by a corresponding quantity of titanium sulphate, zirconium nitrate, zinc nitrate, thorium nitrate, nickel nitrate or a mixture of these. this.

   The obtained reaction product is a non-siliceous aluminum base exchanger which is not a specific catalyst for the reduction reaction, but is diluted with a three-component, catalytically active zeolite and forms a catalyst. well-dosed contact mass for the catalytic reduction of aromatic nitro compounds, such as those from izitrobenzine to aniline, from chloronitrobenzine to chloraniline, α-nitronaphthaline to naphthylamine, etc.



  The reaction product is removed by suction, pressed and washed thoroughly with water; it is dried and then broken into pieces which can be treated with a 2-6% solution of copper nitrate to partially replace the alkali in the exchangeable part of the base exchange body. Cobalt nitrate, iron nitrate, nickel nitrath, alone or in mixture, can partially or completely replace copper nitrate.

   The products can also be treated with. salts of the oxymmetallic acids of the fifth and sixth groups of the periodic system, such as the acids of vanadium, tungsten, molybdenum, tan tal, chromium or uranium. One can, for example, make use of a solution of van- date of ammonium at 1 ° and, in any case, after the soluble constituents have been washed away, what is called a body resembling .a salt is formed.



  In the contact masses described in this example, the base exchange body, non-siliceous, with aluminum can be considered. as a complex regulator for the catalytic converter. The action of the regulator can be further dosed by the addition of regulating favors, such as silicates of heavy metals such as copper, titanium, manganese, zirconium, cerium, thorium, and light metals such as beryllium, calcium, magnesium and barium. One or more of the above-mentioned silicates can be added and they can advantageously be formed on site.



  It is also possible to substitute for part or all of the metal salt component of the base exchange body corresponding quantities of a <B> to </B> 5-1011o solution of beryllium nitrate, zirconium nitrate, thorium nitrate or aluminum nitrate. The catalytic efficiency of the mass can also be increased by the introduction of catalytically effective elements. by exchange of bases, making use, for example, of a 10% solution of copper nitrate, silver nitrate, tin chloride, nickel trate, iron nitrate, etc., singly or in mixture .



  Instead of encrusting the catalytically active base exchange body in a non-siliceous, catalytically inactive base exchange body, it can be encrusted in well known dilute or undiluted base exchange polysilicates or in natural neutral polysilicates or artificial neutral polysilicates. Polysilicates, or zeolites, base exchangers.

   two or three components, aluminum, cadmium, titanium, zirconium, silver, copper and nickel are well suited for this use. In the case of products containing silver, copper or nickel, they can be considered as additional catalytically effective components.



  If large quantities of nickel, cobalt or iron are used, or a mixture thereof, as constituents for the preparation of such contact masses, the aromatic nitro compounds are not only reduced. into the corresponding amino compounds, but in many cases are additionally hydrogenated.

   Thus the nitrobenzine not only is reduced to aniline, but undergoes further reduction to cyclohexylamine, dicyclohexylamine and cyclohexylaniline. The proportions of these reaction products obtained will depend on the reaction temperature and the amount of hydrogen used. At low temperatures, such as 180-200 C, the main product is aniline, while at higher temperatures, such as <B> 220-270 </B> <I> C, </ The main reaction products are hydrogenated amino compounds.

   A suitable excess of reducing gases can be used, which may be 5 to 15 times the theoretical amount necessary for the reduction and hydrogenation to be effected.



       Example <I> 5: </I> 15 to 20%, by weight, of copper nitrate in solution are impregnated with 60 parts of pumice stone powder which is subsequently treated with a quantity of hydrate solution of <B> 10% </B> sodium sufficient to precipitate copper as a hydrate in a finely divided state throughout the pumice powder. This product is then stirred in 24 to 80 parts of a commercial sodium-based water glass solution which has been sufficiently diluted with water so that the pumice powder can be held in suspension therein.

   This suspension is then made weakly ammoniacal, and then 9 parts of copper in the form of cuprammonium nitrate, or cuprammonium carbonate, diluted, and one part of aluminum in the form of a saturated solution of sodium aluminate.

   A sufficient quantity of <B> 10% </B> copper nitrate solution is then introduced in a thin stream to precipitate a sodium-aluminum-vented base exchange body, which is diluted with < B> there </B> pumice stone powder impregnated with <B> hydrate </B> copper. The reaction product should be neutral or alkaline with respect to phenolphthalein, or be only weakly acidic thereto, being strongly alkaline α. with regard to the sunflower in all cases.

   The precipitate is pressed, washed moderately, dried at 80--100 ° C., then broken into pieces. Preferably reduced with gases containing hydrogen, at 220-850 C, <B> the </B> product obtained which then constitutes a firm contact mass, non-pyrophoric and giving no dust, which is eminently suitable as a catalyst for the reduction of nitro compounds to amines by means of gases containing hydrogen. So, for example, nitrobenzine can be reduced to aniline at 180-260 C, especially in a circulatory process with a large excess of hydrogen.

   The circu latory process allows a very complete and efficient use of all the hydrogen and the yields reach almost theoretical values.



  Care should be taken in choosing the materials used in the construction of the converter. The converter should preferably be made of copper or, at the very least, those parts thereof which come into contact with the reaction gases should have a copper surface. If iron is used in the converter, it is desirable to render it inert by coating it with the disclosed contact masses, or constituents thereof. Iron can also be made inert with alkali metal salts of acids of metals of the fifth and sixth groups of the periodic system.

   In the circulatory process, the aniline and water formed by the reduction of nitrobenzine are separated from the gases containing excess hydrogen before they are put back into circulation. The gases containing hydrogen are then adjusted to the desired volume and the desired quantity of nitrobenzine is supplied to them. Almost quantitative yields are easily obtained in such a process. .- Example <I> 6:

  </I> Mix with 50 parts of monazite sand waste, 50 parts of glaucosil (residue, washed with acid, green sand) and 50 parts of copper ore as <B> there </B> malachite, 45 to 55 parts of SiO 'in the form of a sodium-based water glass solution sufficiently diluted with water, the dilution being sufficient so that the suspension remains just easy to stir.

   10 parts of AlzO3 in the form of saturated sodium aluminate solution are stirred therein and the mixture is then treated with 15 parts of cupric nitrate, containing 3 molecules of water, as a 25-30% solution. , and 20 parts of a saturated solution of chromium nitrate containing 9 molecules of water. A base exchange body precipitates which is separated and washed in the usual manner.

   After drying the. mass at temperatures preferably below <B> 100 </B> C, it is subjected to the action of a humid atmosphere, then it is placed on a filter and hydrated by running off water on it. After hydration is complete, the water is replaced with 2-3% hydrochloric or nitrogen acids to remove some of the exchangeable alkali metal present in the base exchange body.

   The leaching treatment is continued until 25-30% of the exchangeable alkali has been removed, after which the diluted base exchange body, partially sivated, is washed thoroughly in order to free it from hydrochloric acid. . or nitrogen, and we dry it again.



  The contact mass obtained as described above is very effective for the catalytic reduction of aromatic nitro compounds and, especially, for the production of a-naphthylamine starting from a-nitronaphthaline at 240-280 C, in the presence a strong excess of hydrogen, preferably in a circulatory process. The obtained α-naphthylamine is practically pure.

   In the same way, aniline can be produced starting from ni-trobenzine at 200 ° C., toluidines starting from the corresponding nitrotoluenes, at 220-230 ° C., from 1-amino-2. 3-dimethylbenzine starting from the corresponding nitroxylene, or amino-chlorobenzines starting from the corresponding chloronitrobenzines.

    at 200-210 C, diaminophenols as well as dinitrophenols, at <B> 260 </B> C. and phenylenedia, mine starting from dinitrobenzine, at 2G0 C, in the presence of excess gas containing hydrogen, such as hydrogen and water gas. Both the yields and the purity are excellent.

   The contact mass described in this example is. very resistant to deterioration by impurities present in the reaction gases. However. it is advantageous to make use, like my earlier ones, of purified benzines. in particular products free of thiophene. because by this means one can prolong the lon gévité of the mass of contact. Such benzines or their homologues can be easily and economically produced by treating with chlorine in the presence, or in the absence, of catalysts, in particular those which favor the chlorination of impurities.

   The traces of chlorine which may remain in this, benzines or their counterparts do not affect the contact mass and the nitro compounds produced by means of such benzines can be used in the, crude form, without preliminary distillation and without this diminishing the effectiveness of the contact mass for months of use.

   If the described contact mass is washed more thoroughly to remove as much of the exchangeable alkali as possible, the resulting contact mass can be effectively used for the reduction of nitromethane to metlivlamine, at 180 ° C. in the presence of a strong excess of bvdrogen. The yields are excellent and the product is free of unrestrained nitromethane.



       Similar results can be obtained when the copper is partially or totally replaced by corresponding tin compounds. A desirable additional catalytic effect can also be obtained, for many of the reductions described above, by the incorporation of small amounts of silver, nickel, cobalt or iron compounds into the base exchange bodies. training course.



       Example <I> i </I> Base exchange bodies, natural or artificial, can be effectively used as carriers or skeletons for catalytic constituents for the reduction of nitrogenous organic compounds. An example of such a contact mass is as follows:

    45-55 parts of S102 are mixed in the form of a dilute sodium-based soluble glass solution with enough kieselguhr or pumice powder to keep the mixture just easy to stir, then combine with the suspension. of kieselguhr in water glass 10 parts of A120 'in the form of 10% sodium aluminate, prepared by dissolving freshly precipitated aluminum hydrate. To the aluminate-soluble glass suspension is added, with vigorous stirring, a 10-fold solution of aluminum chloride or nitrate containing 7.5 parts of A120 ', with or without the addition of silicates such as calcium silicates or magnesium.

   A gelatinous mass precipitates which, after suitable separation and drying, is formed. hydrate with water. The mass obtained has practically no catalytic efficiency for the reduction of nitro compounds. The product is then washed with a 2-3% solution of sulfuric, hydrochloric or nitrogenous acid in order to remove the maximum amount of exchangeable alkali. The resulting leached base exchange body is impregnated with solutions or suspensions of tin or copper compounds or a mixture of the two.

   Thus, for example, one can introduce in this way copper formate, copper oxalate, copper nitrate, or freshly precipitated copper carbonate, with or without the presence of silver or zinc salts. . The mass obtained, which is suitable for the catalytic reduction of aromatic compounds nitrated to the corresponding amines, for example: from nitrobenzine to anil, is then reduced with gases containing hydrogen at 250-300 C, the conditions reaction being the same as those described in the first examples.



  If we push the leaching further, (the way to remove part of the aluminum oxide as well as the exchangeable alkali, we obtain a complex compound of silicic acid, diluted with silicates, which is an excellent diluent for base exchange bodies due to its high absorbency and adsorbing power. Any other natural or artificial zeolite, diluted or undiluted, can be treated in the same way as the three-component zeolite described above. above.



       Example <I> 8: </I> We dilute with 8 to. 70 volumes of water. 10 to 50 parts of i02 <B> Sol ,, </B> form a commercial sodium-based water glass solution and ammonia is added until the cloudiness that forms first disappears. In this solution, kieselguhr, pumice powder is stirred. charcoal, colloidal SiO2, or nickel ore, silver free, powdered, up to. what the mixture remains just easy to stir.

   Prepare a 10% aluminum nitrate solution and dissolve 30 parts of nickel nitrate, containing 6 molecules of water, in diluted ammonia water to form a complex solution of nickel nitrate. ammonium. This latter solution is stirred into the water glass suspension and sufficient aluminum nitrate solution is added until the reaction mixture becomes weakly alkaline or neutral to phenolphthalein. A firm, light blue jelly precipitates, which when stirred turns into an easily filterable aggregate. The precipitate is a dilute base exchange body containing nickel and aluminum in non-exchangeable form,

      and sodium and ammonium in exchangeable form. The mechanical strength of the product can be increased by washing with dilute water glass solution and drying; it constitutes an excellent mass cl, contact for the catalytic reduction of. organic nitrogen compounds.



  The contact mass thus prepared can also be pulverized and reduced with gases containing hydrogen at 250-350 C and can be used for the catalytic reduction of nitrogenous organic compounds in the liquid phase, at room temperature. one operates either at high temperatures, with or without pressure. It is also possible to rob or cover with the finely divided contact mass, carrier materials of natural or artificial origin, such as pumice stones, diatomaceous stones, fragments of pottery, metal granules, etc.

    the artificial carrier materials include the hieselguhr-soluble glass compositions. Organic or inorganic adhesives can be used to adhere the contact mass to the carrier fragments. These contact masses can be used for vapor phase or liquid phase reductions of organic nitrogen compounds. When the reaction is carried out in the liquid phase, the nitrogenous organic compounds are preferably salted, in the form (the liquid or solutions, on the contact mass fragments,

   in a tower in the presence of hydrogen or gas containing it, which can advantageously pass in countercurrent with respect to the liquid.



  Base exchange bodies which form valuable reduction catalysts can be prepared by replacing part or all of the aluminum nitrate with corresponding solutions of thorium, titanium, chromium, beryllium salts. , zinc, zirconium, vanadium, cadmium, lead, copper, silver, - gold or tin. The particular strength of the solution is not essential and may vary considerably.



  Similar products can also be obtained; by substituting water-decomposing cations for the alkali metal cations such as aluminum, thorium, titanium, chromium, beryllium, zirconium, vana dium or zinc. In some cases, it is also desirable to introduce nickel by base exchange. The introduction of alkaline earth metals by base exchange is also sometimes advantageous, since it increases the resistance of the contact mass to harmful agents present in the reactive gases or vapors.



  We. can form bodies resembling the salts of the exchange bodies (the bases described above by reacting them with salts of the acids of tungsten, chromium, molybdenum or vanadium, after the exchange of bases has taken place. of catalytic elements, such as aluminum, thorium, titanium, chromium and zirconium. is particularly advantageous in compositions of contact masses of this kind, especially when used for the reduction of nitro compounds, because these reactions result in the.

    water formation as one of the cl # @ reaction products.



  The contact masses described. when we make it; use at low temperatures, avc- strong excess of hydrogen. act to transform nitrated aromatic compounds. like nitrobenzine, in high purity amines, especially when the temperature is between 120 and 200 C.

   At higher temperatures, from 220 to 300 ° C. the amines begin to hydrogenate to compounds such as cyclohexylamine, dicyclohexylamine and cyclohexylaniline, in the case of nitrobenzine, and as the temperature rises. these hydrogenated compounds become the main products of the reaction. Nitro aliphatic compounds. in the presence of a large excess of gas containing hydrogen. donate amines at 180--250 C.

   Alkyl nitrite, oximes, Schiff's bases and lc-nitriler can also be reduced to valuable amino compounds, by the usual methods, in the presence of catalysts described above.



  It is also possible to reduce heterocyclic compounds. Thus, for example, pyrrol can be reduced to pyrrolidine. pyridine to amylamine, with rupture of the. closed chain, convert quinoline to tetrahydroquinoline at 200 C, etc.

   Examples of reductions in the liquid phase are the reductions of solutions of Schiff's bases <: r secondary amines, at the temperatures of the places where the operation is carried out, by making use of a: mass of 2ontact sprayed, as described, the quantity of contact mass being about 40 to <B> 50% </B> of the Schiff base which is used, and taking care to obtain a constant and intimate mixture of catalyst with the Schiff base to ensure the best results.

   Examples of high temperature and high pressure reductions, making use of the contact mass compositions described above, are the reduction of nitro-benzine with 10 to <B> 15% </B> finely contact mass. sprayed, at 100-120 C, under a pressure of 10 to 15 atmospheres of hydrogen: aniline is the main product, but it is possible to stop the reaction at intermediate phases, such as azoxy phases, a.zo and hydrazo. by varying the amount of hydrogen which is used.



  <I> Example 9: </I> 100 parts of a zeolite such as "periilutite", which can be obtained chemically for water softening, are treated with a 3-3 copper nitrate solution. 5 until a maximum amount of exchangeable alkali is replaced by copper oxide. It is advantageous to use base exchange bodies having a strong exchanger capacity (the bases and, preferably, use will be made of aluminosilicate type zeolites. Other zeolites of the same type, in which aluminum is replaced in part or in whole by other amphoteric metal oxides, also have a strong base exchange power.



  The copper zeolite, prepared as described above, can be applied for the catalytic reduction of aromatic nitro compounds, such as nitrobenzine, nitrotoluene or nitranisol, to corresponding amines in the presence of 10 to 15 times the theoretical amount of hydrogen. in a circulating process. It is also possible, instead of a gas containing hydrogen, to make use of carbon monoxide and water vapor; when, for example, nitrobenzine vapors are mixed with sodium oxide. carbon and va scared of water and passed over 1a.

    contact mass at 200-220 C, the result is an aniline of excellent purity.



       Instead of introducing copper, we can introduce. likewise other catalytically active radicals making use of, for example, a 5-10 ic # solution of nickel nitrate which is run off repeatedly. on the zeolite at 40-50 C, to introduce a maximum of nickel. Such contact masses can be used for the. reduction of nitrobenzine to aniline by porizing nitrobenzine and steam at 110-130 C, mixing with hydrogen gas and passing over the contact mass under the appropriate loads.

   A high-quality, nitrobenzine-free aniline is thereby obtained. In a similar fashion, orthonitranisol can be reduced to orthoaminanisol.



  We can still measure the contact masses described, to increase their efficiency, by subjecting them to (reactions with acid salts of metals of the fifth and sixth groups of the periodic system, such as vanadium, chromium and molybdenum, in order to to form what are called salt-like bodies. This can be done advantageously by running a <B> 1% solution. </B> for example an ammonium vanadate solution on the contact mass, then washing the body, resembling a salt, obtained.

   The resulting contact masses, containing nickel or copper in exchangeable form, are well suited for the catalytic reduction of pyuridine to piperidine with a large excess of hydrogen-containing gas at 200 C.



  The base exchange bodies described. containing copper in an exchangeable form, can also be thoroughly leached with dilute acid to remove alkali which has not been replaced by copper. The contact masses thus produced are well suited for the reduction of 3-nitro-pyridine to 3-aminopyridine of high purity, making use of an excess of hydrogen at 200-250 C.

   It is also possible to use the same contact masses for the reduction of nitromethane to methylamine of higher quality. 200 C '.- Example <I> 10: </I> Is dissolved in 15 parts of water JO parts of zinc nitrate containing 6 molecules of water and sufficient concentrated sodium hydrate is added to transform zinc as the corresponding zincate.

   16 parts of chromium oxide are then prepared by precipitating it with ammonia from a solution of chromium nitrate at <B> 10%. </B> The chromium oxide precipitates in the water. state of fine division and after washing it completely, it is stirred in 150 parts of water to form a slurry. A third solution is prepared of 48 parts of copper nitrate, containing 3 molecules of water, dissolved in 280 parts of water, or a corresponding amount of SnCl-. 3 H20, and the suspension of chromium oxide is stirred therein.

   The mixture is then poured into the zincate solution, with vigorous stirring, taking care that the reaction mixture always remains alkaline. A jelly forms which is separated by suction and dried at 80 ° C., and which forms hard glassy fragments of a non-siliceous base exchange body containing zinc and copper, or tin, and diluted with finely divided chromium oxide. The products are valuable contact masses for the reduction of nitrogenous organic compounds.

   The chromium oxide can be substituted by salts of chromic acid, especially copper chromate, cadmium chromate or aluminum chromate; or salts, especially copper, vanadic acid, tungstic acid or uranic acid salts, singly or in admixture can be used.

   A lead oxide can also be used as diluent; or a part of the zinc may be replaced by a corresponding amount of plumbite. When lead is present, or is the main constituent, the contact masses reduce nitro aromatic compounds to the corresponding azoxy and azo compounds at 200 ° C., in the presence of an excess of hydrogen.

   When lead is absent, use can be made of the contact masses for the reduction of aromatic nitro compounds, for example of nitrophenols to aminophenals, at 250 ° C. with an excess of hydrogen, the reaction conditions being the following. same as those described in the previous examples.



  <I> Example 11: </I> The following solutions are prepared: 1o Dissolve in 200 parts of water 30 parts of nickel nitrate containing 6 molecules of water and add sufficient ammonia water to 25%, until a clear solution of nickel ammonium nitrate is obtained.



  4 parts of freshly precipitated aluminum hydrate are slurried with 50 parts of water. then treated with sufficient sodium hydrate solution of ten times the normal strength to form a clear solution of sodium aluminate.



       3c 1.0 parts of chromium nitrate are dissolved in 150 parts of water with 9 molecules of water, then treated with sufficient sodium hydrate solution, of a strength tenfold than normal . to form sodium chromite.



       4o Is dissolved in 50 parts of water 8 parts of zinc nitrate and treated with a quantity of sodium hydrate solution, of a strength ten times the normal, sufficient to form sodium zincate.



       51 '40 parts of nickel nitrate are dissolved in 200 parts of water with 6 molecules of water.



  60 11 parts of zirconium nitrate are dissolved in 150 parts of water with 5 molecules of water.



  70 16 parts of titanium nitrate are dissolved in 160 parts of water. Solutions 1, 1, 3 and 4 are mixed together and stirred therein 300 parts of kieselguhr, pumice powder or activated charcoal, or a mixture thereof. These diluents can also be replaced, in part or in whole, with silver-free nickel ore. The solutions 5, 6 and 7 are then mixed together and added to the suspension with vigorous stirring.

   A gelatinous reaction product is formed which, if strongly alkaline with respect to phenolphthalein, can be neutralized with 5/001 nitrogen acid until it is just neutral. results in an increased yield of base exchanger body. The reaction product can also be soiled with a saturated solution of ammonium carbonate.



  Once dried at temperatures preferably below 100 ° C., the product constitutes a base exchange body containing sodium,. ammonium, nickel, aluminum, chromium, zinc, zirconium and titanium. When broken into fragments, the contact mass can be used for the catalytic reduction of aromatic nitro compounds to hydrogenated amines, for example: from nitrobenzine to cyclohexylamine at 240-260 ° C.



  The contact mass can also be leached with dilute hydrochloric acid to remove the exchangeable alkali to the maximum extent. The leached base exchange body, in particular in the form of a fine powder, can be used for the reduction of nitro compounds in the liquid phase. When copper is used instead of nickel, the leached contact masses are well suited for very sensitive catalytic reductions of organic nitro compounds, for example: for the reduction of 3-nitropyridine to 3-aminopyridine in the presence of 'excess hydrogen at 180-200 C.

 

Claims (1)

CLAIM Process for the reduction of organic nitrogen compounds, characterized in that this reduction is carried out in the presence of a contact mass containing at least one body of a microporous structure which results from the formation of a body exchanger of bases, and containing catalytically active constituents. SUB-CLAIMS Method according to claim, for the realization of which is employed a contact mass further containing action regulators. 2 A method according to claim and sub-claim 1, for the. embodiment of which is employed a contact mass containing at least one metal serving to promote the effect of the regulators. 3 A method according to claim, characterized in that the contact mass is prealy treated with reducing gases. .l- Process according to claim, characterized in that the compounds to be reduced are used in the form of vapors reacted at sufficiently low temperatures, in the presence of the aforementioned contact mass. 5 A method according to claim, characterized in that the reduction is carried out by means of a reducing gas containing hydrogen in an amount at least equal to ten times the theoretical amount necessary to effect the desired reduction. A method according to claim, characterized in that the reaction is carried out at temperatures not substantially exceeding 250 C.