BE548439A - - Google Patents

Description

       

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   The present invention relates to the synthesis of organometallic compounds. More particularly, the invention relates to a novel process for the production of certain organometallic compounds, that is to say compounds of a polyvalent metal having at least a metal-carbon bond, and by means of a new and improved reaction.



   Organometallic compounds, as defined above, have long been of interest to chemists and constitute an interesting field of study. During the years of research carried out on the methods of synthesis of this vast category of body, it has been proposed a variety of generalized reactions which are revealed in the scientific literature and in patents. Methods of preparation have recently been comprehensively reviewed by Jones and Gilman (Chemical Revieuws, vol. 54, pages 835-890, October 1954).



   About two dozen generalized methods are known in the art for preparing organometallic compounds, however these methods do not include practical methods for preparing compounds such as:
MR H n m where M is a polyvalent metal capable of forming metal-carbon bonds, n and m are at least 1, and n + m is the valence of M.



  Compounds of this type have been found to be particularly useful in that they are particularly effective reagents for the direct formation of new metal-carbon bonds by reaction on an olefinically unsaturated hydrocarbon. The bodies obtained are useful as
 EMI1.1
 high-energy fuels, as ignition agents or corm; l'ntori, 1ed.iaj :: t''es (!; 1fnii3: 1 la = 'sx, ti c¯ utû :. vorposôs: ax, l? otn : Lâ..icuor>:;, Ip,: 'rw, r;: WS:. "' C, tl: 1." TJ,,, iyr7 '....: W ¯.û.t' ¯ :
Numerous processes have been proposed for making important organo-lead compounds, and in particular lead-tetraethyl for use as a commercial anti-knock.

   In all such commercially successful processes, an appreciable proportion of the lead introduced into the reaction remains unaltered and must be recovered, processed and recycled. Although many technically valuable processes have been proposed. bles to convert this by-product lead into organo-lead, these processes have not been used commercially, mainly due to the high consumption, and that without chance of recovery, expensive chemicals needed to achieve this conversion.



   One of the aims of the present invention is to provide a new reaction giving greater working flexibility. A particular aim of several embodiments according to the invention is to provide a process for the preparation of organic compounds of polyvalent metals. The present invention is to provide a process for making organometallic compounds substantially directly from the metal and an organic nucleus existing in a relatively stable state, and generally corresponding to the organic radical of the final organometallic product.



  A particular object of the present invention is to provide a process for making organo-lead compounds, in particular lead-alkyl compounds, by direct reaction of metallic lead with constituents containing the organic groups in question. A particular object of the present invention is to manufacture lead-tetraethyl directly from metallic lead without simultaneous formation of undesirable by-products. Another object of the present invention is to provide a new and improved process for making a hydride of organo-aluminum, in particular an aluminum-dialkyl hydride,

     from metallic aluminum.

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 More precise is to provide a method for introducing alkyl groups into an aluminum-alkyl hydride compound without the need to initially form and recover the aluminum hydride. Another object is to provide a method. improved for preparing metals from their compounds at low temperature. Other objects will become apparent in the following discussion of the present invention.



   The process of the present invention essentially consists of hydrogenating an organometallic compound in the presence of a metal. In several embodiments according to the present invention, by organometallic compound is meant a compound containing more carbon-metal bonds than the desired product. The result of the process and the reaction indicated, an initial product containing on average a reduced number. carbon-metal bonds, but an increase in the total product, as a result of the reaction of the metal initially present, and rearrangements and substitution of the original carbon-metal bond with carbon-hydrogen bonds.



  As a result of this treatment a product is obtained which is susceptible to further olefin treatment to give a final product in which all metal valences are satisfied by carbon-metal bonds. In some cases the initial product is relatively unstable, and its reaction with any olefinic or other reagents becomes an important feature of the process.



   As can be seen from the general expression given above, the metal component of the organometallic compound may be the same as, or different from, the free metal used in the reaction. In embodiments where they are different, the free metal used will be called the primary metal, and the metal of the initial organometallic compound will be the secondary metal.

   The process is illustrated or generally represented by the following equation:
 EMI2.1
 organic compound metal. compound secondary metal hydride- + hydrogen + organic primary- + primary metal than secondary primary
According to a modification to the process according to the invention, the simultaneous reaction takes place under high pressure and at moderate temperatures between a trialkyl aluminum, metallic aluminum and hydrogen. The process is generally summarized by the following reaction:

   
 EMI2.2
 Aluminum + hydrogen + Aluminum hydrides ÉÎÉÎ ny ogene + metallic> aluminumalkyl
It has also been found that tiethyl aluminum can be prepared directly from aluminum, hydrogen and ethylene. The present invention generally includes the process of treating metallic aluminum with ethylene and hydrogen. in the presence of a liquid phase of triethyl aluminum. The metallic aluminum used is preferably in divided form, for example aluminum chippings prepared in a nitrogen atmosphere.

   In a precise embodiment of the invention, the process for preparing triethyl aluminum comprises on the one hand contacting the particulate aluminum with a quantity of triethyl aluminum sufficient to wet the surfaces of the metal and on the other hand, heating the reaction zone to a temperature between 30 and 130 ° C. under a pressure of 10 to 300 atmospheres of a gas mixture containing hydrogen and ethylene.

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   In an embodiment of the foregoing general type according to the present invention, aluminum is normally used in the form of finely divided or powdery solids which have been prepared in a fully inert gas atmosphere such as for example argon, nitrogen, or methane.



   In this atmosphere, oxygen or humidity should preferably be strictly excluded. Solid aluminum is introduced into a reaction zone taking precautions to prevent its contact with an oxygen-containing gas or with the aluminum. moisture. An amount of aluminum triethyl, sufficient to wet at least a portion of solid aluminum, is then introduced into the reaction zone and this zone is sealed with the exception of the conduits. intake of hydrogen and gas containing ethylene. The gas containing hydrogen is introduced into the reaction zone, and the pressure of hydrogen is increased to the desired operating level which is generally over-atmospheric but less than 300 atmospheres approximately.



   Concurrently, or after reaching the desired hydrogen pressure, an ethylene-containing gas is introduced into the reaction zone at a pressure which varies over a wide range but generally not greater than a partial pressure of 100. atmospheres. The contents of the reactor are heated to the required temperature level and maintained at that level for a period which varies according to the improvements in the apparatus and the reaction, temperature, and pressure conditions employed. contact, it is preferable to continuously agitate the contents by means of controlled stirring devices or by use of a tilting reaction zone in which the solids move sporadically from one end to the other. In some cases,

   a contact time of the order of about 20 hours is required, although shorter contact times of the order of 0.5 hours are also suitable under certain reaction conditions. This contact time is usually a function of The relative magnitude of the finely divided aluminum solid layer of the aluminum particle size, the relationship between the pressure and temperature of the reactants and the proportions of the reaction zone i.e. the ratio between the depth and the surface exposure of a straight section.



   As will be seen from the detailed description below, the terms of the preceding expression should not be taken in the strict sense. Thus, the expression “organic compound of secondary metal” does not mean that all the valences of a polyvalent secondary metal are necessarily satisfied by metal-carbon bonds, but that for example some of the valences may carry metal-hydrogen bonds. Similarly, the term "secondary metal hydride" does not mean that this combined product has all of its valences saturated with hydrogen, but bears substantially more hydrogen bonds than the organic secondary metal compound used as the initial reactant.

   the expression "organic primary metal compound" is not restricted (in the case of a polyvalent primary metal to compounds in which all the valences of the metal are saturated with metal-carbon bonds, but it generally includes compounds having at least one carbon-metal bond.



   In all cases, the process is carried out under hydrogenation conditions, that is, under conditions severe enough to apparently break a carbon-metal bond and in its place form a metal-hydrogen bond. Usually these conditions include a moderately high temperature and appreciable hydrogen pressure. Examples of these conditions are temperatures of about 25 to 200 ° C and partial pressures of hydrogen of about 5 to 1000 atmospheres. The upper limit of the temperature range is largely determined by the stability of organometallic reagents and products. Thus, in the intended reaction

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 to prepare lead-tetraethyl,

   it is preferable to use temperatures not exceeding about 110 C. Furthermore, when it is desired to use the upper allowable temperature range to achieve a rapid reaction, it is preferable to use in the reactor the thermal stabilizers. - ques capable of preventing the thermal decomposition of organoplomb compounds, Types of bodies which are suitable for this purpose, and which are revealed for example in US Patents Nos. 2,660,591, 2,660,592, 2,660,593, 2,660,594, 2,660 595 and 2,660,596 all of November 24, 1953, are in particular naphthalene, styrene, azobenzene, furfuryl alcohol, oleic acid, styrene dibromide, diisobutylene, etc.



   Recently, processes have been developed for making organ-aluminum compounds, and in particular aluminum-trialkyl compounds. A characteristic of organo-aluminum compounds is that they form stable organo-aluminum hydrides, and among others. the most stable are aluminum-dialkyl monhydrides. On the other hand, organo-lead hydrides are slightly less stable.

   In the overall process of the present invention, the main result is the joint formation of organo-aluminum hydrides and organo-lead hydrides. In a preferred embodiment according to the present process, it is desirable to take a proportion of reactants such that the predominant aluminum product is, in the case of alkylated derivatives, aluminum-dialkyl monohydride, and to carry out the process in the presence of an olefin in order to stabilize the organo- lead in the form of tetraorgano-lead Thus, in a particularly useful embodiment according to the present invention, the aluminum triethyl is reacted with the metallic lead in the presence of hydrogen and ethylene, so that the reaction mixture is converted into almost entirely in a mixture of aluminum-triethyl and lead-tetraethyl,

   the latter being an important anti-knock agent. It can be seen from the above that, by the present process, it is ultimately possible to be able to prepare lead-tetraethyl directly from ethylene and hydrogen, while aluminum-triethyl, which is transformed in the reduction stage into aluminum-diethyl hydride in order to then regenerate aluminum triethyl in a subsequent reaction is not consumed and can be recycled to the first stage. a convenient process for preparing lead-tetraethyl from lead, hydrogen and ethylene, without consuming or using other chemicals. Similar considerations apply to the manufacture of other organo- compounds. lead described below.



   A particularly efficient source of the metal used in the process is a subdivided and chemically treated metal, so in reactions where one of the by-products is an elemental metal, this metal so liberated is frequently in the effectively divided and active state. , and therefore ideally suited for the present process. Accordingly, the present process can be an advantageous supplement to other processes.



   It should also be noted that reactive alloys can be used in the present process, when mixed organometallic compounds are used, the metals of the alloys being the same as those of the organometallic compounds in question, or different from. these.



   Although the present process is generally applicable to the direct reaction of metallic lead in accordance with the above, consideration should be given to the form in which metallic lead is used. Although the reaction mechanism is not clearly known. , it can be assumed that organo-lead hydrides form on the surface of metallic lead, and are then stabilized by reaction on the constituents of the reaction system. The state of metallic lead is important for carrying out a practical reaction and it is desirable to use free lead suspected

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 One of these forms of lead is obtained by various processes previously proposed or employed commercially to manufacture organo-lead compounds,

   and whereby free metallic lead is obtained as a by-product. In the process most widely adopted commercially, and which concerns the reaction of a sodium-lead alloy with ethyl chloride, three atoms of free lead are obtained for each mole of lead-tetraethyl obtained. according to the present invention with the current commercial process, the lead thus obtained is directly and completely converted into organo-lead.

   Thus, after the reaction between the sodium-lead alloy and ethyl chloride, the lead capable of alkylation can be reacted, in an autoclave, with an organometallic compound, such as lead-tetra7thyle obtained previously. in said process, in the presence of hydrogen and ethylene, to obtain an additional equivalent amount of lead-tetraethyl. By such a process, a reaction cycle is effected, and in a coordinated commercial operation, a more or less fixed amount of consume-tetraethyl lead is maintained as an intermediate for the formation of tetraethyl lead by the process according to claim from the basic reactants which are metallic lead, hydrogen and ethylene.



   Other examples of lead which can be used successfully in the process of the invention, are in particular lead powders resulting from the decomposition of organo-lead compounds by heat, for example lead deposited during the thermal decomposition of organo compounds. Certain other forms of lead powders which are sufficiently active to serve in making lead-tetraethyl can be obtained by the process according to the invention, by crushing or otherwise finely dividing metallic lead, especially when This is done under a nitrogen atmosphere which prevents surface oxidation of the lead. Another example of a process for preparing finely divided lead suitable for the practice of the present invention,

  is the precipitation of lead by reduction of its compounds. Other methods involve processes such as electrolytic deposition will occur to those skilled in the art.



   Lead alloys, especially alloys containing alkaline earth and alkali metals, are also a good source of lead and have been used with success. Sodium-lead alloy is a particularly suitable alloy for this purpose. Examples of lead alloyed metals which have been used successfully in the practice of the present invention are calcium, potassium and magnesium. In general, one can use as a source of lead for the process of the invention no any alloy which reacts according to the following equation: metal-lead alloy + lead-tetraethyl ethyl chloride + lead + metal chloride.



   On the other hand, certain alloys which enter with difficulty in the preceding reaction, or which require the use of relatively high temperatures, react satisfactorily and at a lower temperature when used as a source of lead for the process. For example, instead of the monosodium-lead alloy, alloys corresponding to Na Pb and Na9Pb have been used with success in the process according to the invention, the yield of conversion of lead to lead -tetraethyl being higher than in any previously known process. Various combinations of lead forms can also be used in the practice of the present invention.



   Another modification of the process of the present invention provides a direct process for obtaining more complex organometallic compounds.



  Thus, by reacting an organo-aluminum compound in the presence of hydrogen,

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 of free lead, and a mixture of olefins, one obtains the corresponding mixed organo-lead compounds. Thus, for example, one can obtain lead-methyl-ethyl-propyl compounds, by reacting aluminum-tetramethyl, hydrogen, metallic lead and a mixture of ethylene and propylene.



  Likewise, it is evident that a wide variety of organo-lead compounds can be obtained directly by this process, although in many cases these compounds could not be prepared by any suitable process. Furthermore, these bodies are obtained without formation of unwanted by-products.



   In the embodiments where they are used, the relation between the secondary metal and the primary metal is as follows: The secondary metal must be higher in the series of redox potentials than the primary metal. Types of combinations of metals entering into reaction in this general process are, for example, the following secondary metal / primary metal pairs: lithium-strontium, lithium-barium, lithium-beryllium, lithium-zinc, potassium-aluminum, potassium-gallium, gallium-tin , tin-bismuth, tin-mercury, and other easy-to-see combinations.



  Double combinations come within the scope of the process, that is to say the process as described above is applicable when there are mixtures of organometallic compounds of two or even more metals. Thus, a type of combination of this kind would be constituted by the alkyl compounds derived from mixtures of sodium and potassium, this mixture being used as organometallic feed material. It also falls within the scope of the process the treatment of a mixture of primary metals to give, concurrently or successively, several organic compounds of primary metal.



   The possibility of applying the process to embodiments using secondary and primary metals will be more easily felt by examining the typical equations below.It is understood that the equations given below are idealized, and that they do not claim to represent the returns actually. obtained nor the proportions of reaction constituents used in a particular embodiment of the process.

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  4 (c2H 3) 3 AI + 6H2 + 3 Pb -------- i 4AlH: 3 + 3 (C2H) Pb
 EMI7.2
 
<tb> aluminum
<tb> triethyl <SEP> lead <SEP> hydride
<tb> aluminum <SEP> leadtetraethyl
<tb>
 
 EMI7.3
 C2HLi + Hz + Ca & 1 'LiH CZH 5CaH -
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<tb> lithium- <SEP> calcium <SEP> hydride <SEP> of <SEP> hydride <SEP> of <SEP> calcium-
<tb> ethyl <SEP> lithium <SEP> ethyl
<tb>
 
 EMI7.5
 2-iC) H7Li + 3/2 H2 + Al ######### 2LiH + (i-C3H7) 2AlH
 EMI7.6
 
<tb> lithium- <SEP> aluminum <SEP> hydride <SEP> of <SEP> aluminumisopropyl hydride <SEP> <SEP> lithium <SEP> diisopropyl
<tb> C2H5Li <SEP> + <SEP> 1/2 <SEP> H2 <SEP> + <SEP> K <SEP> LiH <SEP> + <SEP> C2H5K
<tb> lithium- <SEP> potassium <SEP> hydride <SEP> of <SEP> potassium-
<tb> ethyl <SEP> lithium <SEP> ethyl
<tb>
 
 EMI7.7
 3 (CH) lg + 3 H2 + 2Ga ### 3MgHz + 2 (CH)

  Ga
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<tb> magnesium- <SEP> gallium <SEP> <SEP> galliumdiethyl <SEP> hydride <SEP> magnesium <SEP> triethyl
<tb>
 
 EMI7.9
 2 (CZH5) 2Mg + H2 + Ga 2CH5TyIgH + (CzH5) ZGaH
 EMI7.10
 
<tb> magnesium- <SEP> gallium <SEP> magnesium- <SEP> galliumdiethyl <SEP> ethyl <SEP> diethyl
<tb>
 
 EMI7.11
 (1-C?) 2Zl g 'H2 + Zn igHZ + {i-C3H7) ZZn magnesium- zinc zinc hydride-diisopropyl diisopropyl magnesium (i-C3H7da) + 2HZ + Sn #### (CZH5) ZSnH2 + NaH, KH (l- c fi r t ..)

   
 EMI7.12
 
<tb> sodium-isopropyl <SEP> tin <SEP> tin dihydride <SEP>- <SEP> hydrides <SEP> of <SEP> sodium
<tb> and <SEP> potassium- <SEP> diisopropyl <SEP> and <SEP> from <SEP> potassium
<tb> isopropyl
<tb>
 

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In a precise embodiment of the present invention, the process is particularly suitable for preparing aluminum-triethyl by contacting particulate aluminum with sufficient aluminum-triethyl to wet the surfaces and then heating the reaction zone. at a temperature of about 30 to 130 ° C. under a pressure of 10 to 300 atmospheres of a gas mixture containing hydrogen and ethylene.



   The organometallic compounds prepared according to the present process are particularly useful for extracting metals from their compounds. Thus, metals can be prepared from their compounds by contacting, under suitable reaction conditions, a compound of the metal. desired, hereinafter referred to as a primary metal compound, together with an organometallic compound of a second, more strongly electropositive metal, and hereinafter referred to as a secondary metal compound. The primary metal compounds mentioned herein are generally compounds of the metals which are found in the transition series of the periodic table.Organometallic compounds with which these primary metal compounds react are characterized by containing at least one carbon-metal chemical bond.



  The metal present in the organometallic reagent is more electropositive than that of the other metal reagent, and it is found that, under suitable reaction conditions, yields close to 100% of free metal derived from the compounds of primary metals can be obtained. indicated above. The product thus obtained is characterized by uniformity of size and a high degree of purity of the particles.



   Furthermore, this method of obtaining metals is also suitable for the preparation of the desired mixtures of metals, by contacting a desired mixture of compounds of primary metals, of at least two different metals, with an organometallic compound of. a metal which is more highly electropositive than each of the other two metals in the reaction mixture. In a preferred form of the present process, the organic derivatives of metals of groups I, II or III-A of the periodic table are used as initial reactants. is particularly advantageous due to the fact that temperatures are used which are notably lower than the melting point of the metal to be prepared, that is to say generally not higher than approximately 300 ° C., and preferably lower than approximately 150 C.

   Likewise, the reaction pressure applied can vary over a wide range, namely from about 1 to 100 atmospheres, and preferably from about 2 to 10 atmospheres. Although the reaction mechanism of the process is not fully understood, it is believed that a methathesis reaction takes place between the initial reactants so as to form an organometallic transition compound of the metal which initially had no carbon-metal bonds, and then this organometallic transition compound! decomposes to give free metal.



  In some cases, not even an unstable transitional organometallic compound is formed, but the free metal appears to be formed directly as a result of a displacement reaction between the secondary and primary metal compounds. In some cases, the primary organometallic compounds formed by the process can be recovered, purified and then decomposed to obtain the desired free metal at a high state of purity.



   The details of the process and its variations will be more readily understood from the following detailed examples.



   EXAMPLE I
In a round-bottom autoclave are introduced about 40 parts by weight of finely divided metallic calcium, for example the calcium lamellae described in US Patent No. 2,561,862, July 24, 1951, and about 100 parts by weight of hexane. dry solvent. About 75 parts by weight of sodium ethyl are added to it. Hydrogen pressure is applied

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 of the order of 275 atmospheres, and the contents are stirred constantly while raising the temperature to approximately 90 -120 C. Contact is continued under hydrogen pressure for a period of approximately 2 hours.



   At this point, the temperature applied to the autoclave is reduced to the ambient level of about 30 C or below and after lowering the temperature the hydrogen pressure is gradually released. The autoclave then contains a mixture. of solid sodium hydride and of calcium-ethyl hydride, suspended in the reaction medium, and a good yield is obtained.



     EXAMPLE II
The following example typically illustrates the application of the process where the secondary and primary metals are both monovalent metals. Substantially the same process which was used in Example I above is applied, except for differences noted below.



   About 100 parts by weight of ethyl lithium is used in a solvent comprising diethyl ether to which is added about 10 - 11 parts of metallic potassium finely dispersed in a liquid vehicle. The reaction is continued under a pressure of d. Hydrogen of about 56 kg / cm2 over a period of at least 1/2 hour. The reaction products have a high yield of potassium-ethyl, C2H5K, and lithium hydride, LiH.



   EXAMPLE III
The following example illustrates the treatment of metals with equal valences, but with different electropositive characteristics, and relates to the hydrogenation of an organomagnesium compound in the presence of zinc foam as the primary metal. Following this example, 75 are reacted with 85 parts of magnesium-diisopropyl, (iC H) Mg, on about 42 parts by weight of zinc foam in the presence of a quantity of saturated kerosene, as a carrier, or, if desired, in the presence of a solvent fully aromatic, such as benzene or toluene, and under high pressure of hydrogen. A high yield of magnesium hydride and zinc-diisopropyl is obtained.



   EXAMPLE IV
The reactor used in this example comprises a stainless steel autoclave fitted with an internal stirrer and an external heating and cooling device. Into this reactor are introduced 621.7 parts of finely divided metallic lead and 342. 5 parts of aluminum-triethyl. The autoclave is closed and hydrogen is introduced into the reaction zone to maintain a hydrogen pressure of about 150 atmospheres. The temperature of the autoclave is slowly raised to 90 atmospheres. - approximately 100 ° C. with internal stirring, the start of the reaction being indicated by a drop in pressure in the reaction zone. The hydrogen pressure is maintained at the initial level for a period of approximately 4 hours, during which the reaction consumes hydrogen.When all hydrogen consumption has ceased,

   ethylene is introduced into the reaction zone at a pressure sufficient to maintain a pressure of about 200 atmospheres in the reaction zone. The consumption of ethylene by the reaction is indicated by a drop in pressure which continues for a period of d About 3 hours during which time ethylene is constantly introduced into the reaction zone to maintain the above total pressure.



  When all pressure drop in the system ceases, the autoclave is allowed to cool to room temperature and the excess pressure of hydrogen and ethylene is released. High conversion of metallic lead to tetraethyl lead is obtained. for a consumption of 6 molar equivalents of hydrogen and 12 molar equivalents of ethylene.

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   EXAMPLE V
This example illustrates the incorporation into the present process of a method currently employed for making organo-lead compounds.



  Thus, 230.2 parts of sodium-lead alloy and 400 parts of ethyl chloride are reacted at a temperature of 85 ° C. for 4 hours. At the end of this time, the excess ethyl chloride was distilled off and to the resulting mixture which included lead-tetraethyl, sodium chloride and highly reactive metallic lead was added 6 mole equivalents of. hydrogen and 12 molar equivalents of ethylene, and 114 parts of aluminum-triethyl. the presence of a quantity of nitrogen sufficient to maintain in the reaction zone a total pressure of about 100 atmospheres at a temperature This reaction is continued for a period of 5 hours, after which the autoclave is cooled to room temperature and the excess pressure is released. By this combined operation, we obtain

  virtually complete conversion of the lead originally present in the alloy, sodium-lead, to lead-tetraethyl. Similar results are also obtained when olefins such as propylene, ethylene and olefins are used instead of ethylene. butylene, amylene and octene.



   EXAMPLE VI
A large excess of zinc-diethyl (C2H5) 2Zn is treated with hydrogen. in the presence of metallic zinc and using the process of Example I, but without inert liquid. At the end of the treatment, a solution of zinc-ethyl hydride, C2H5ZnH, in the excess of liquid zinc-diethyl is obtained The olefin treatment is then started by applying a partial pressure of ethylene of 150 atmospheres, which converts the amount of zinc-ethyl hydride to additional zincdiethyl.



   EXAMPLE VII
The procedure of Example IV is repeated, except that 323.4 parts of lead-tetraethyl (C 2H5) Pb are used, instead of aluminumtriethyl o A high conversion of metallic lead to lead-tetraethyl is obtained for a Consumption of 6 molar equivalents of hydrogen and 12 molar equivalents of ethylene Similar results are also obtained when lead-tetraphenyl, lead-tetramethyl and lead-tetrabutyl are used instead of lead-tetraethyl. in this example, propylene, butylene, amylene, hexene and octene are used instead of ethylene, satisfactory and similar results are obtained.



   EXAMPLE VIII
The procedure of Example VII is repeated except that an equivalent amount of isoamylene is used instead of ethylene in the olefin addition step. Further, before the addition of isoamylene about 30 parts of benzcyl peroxide are added to the reaction zone.



  The consumption of olefin by the reaction system appears to be completed about 1 hour after the addition of olefin and peroxide to the reaction zone, which contrasts sharply with the normal time of 15 hours required for this reaction in 1. 'absence of peroxide. The process is completed and the product is perfected to give an excellent yield of leadethyl-triisoamyl.



   EXAMPLE IX
In an autoclave are introduced about 190 parts by weight of aluminum-triethyl (C2H5) 3Al, and about 11 parts of aluminum in pail-.

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   The autoclave is sealed and subjected to a pressure of dry hydrogen of about 250 atmospheres. The contents are then gradually heated to an operating level of about 100-110 C, and the contents are stirred. during this operation. These conditions are maintained for a period of about 2 hours, supplying additional hydrogen if desired, and at this time the temperature of the contents of the autoclave is brought back to ambient level;

   the excess hydrogen pressure is released. A high yield of aluminumdiethyl hydride (C2H5) 2AlH is obtained, dissolved in an excess of aluminumtriethyl. The product can be isolated by vacuum distillation.



   EXAMPLE X
The reactor used comprises an autoclave equipped with internal stirring device and external heating and cooling.



   In this reactor are introduced 600 parts of normal hexane and 90.7 parts of nickel monosulfide, having a particle size less than
1.5 mm. To this mixture are added, with stirring, 72 parts of lithium ethyl partially dissolved and suspended in 200 parts of n-hexane.

   The temperature of the reaction mixture rises slowly during the addition of lithium ethyl, indicating almost immediate initiation of the reaction when the two reagents come into contact. The autoclave is sealed after the addition of lithium-ethyl, and the reaction is maintained at a temperature of about 60 to 70 C by external cooling,. When the temperature begins to drop as a result of the reduction in the reaction rate,

  heat is applied to maintain temperature within the above interval for a total of approximately 2 hours The mixture is cooled to room temperature and the pressure built up in the system is released by removing the seal from the autoclave The reaction mixture is then filtered to remove the solids which consist essentially of a mixture of finely divided metallic nickel and lithium sulphide. This mixture of solids is then extracted with water to remove the soluble lithium sulphide. , thereby recovering a high amount of finely divided nickel having a uniform particle size and an oxide and nitride free surface.



   Likewise, when platinum sulphide, titanium tetrachloride, zirconium tetrabromide, vanadium pentoxide, palladium sulphide, chromic chloride, cadmium sulphide and cuprous sulphide, satisfactory powder yields of platinum, titanium, zirconium, vanadium, palladium, chromium, cadmium and copper are respectively obtained.



   Instead of the fully alkylated aluminum-alkyls used in the previous examples, the initial process reagents may be the more highly alkylated aluminum hydride compounds, i.e. those which contain on average two or more. organoalkyl substituents on aluminum.In such a case, the product will contain, on average, one to two alkyl substituents.In other words, the product in such a case is a mixture of aluminum-dialkyl hydrides and dihydrides of Aluminum-mono- alkyl. Products of this nature are normally more unstable and more pyrophoric than aluminum-dialkyl hydrides. Thus, when treating aluminum-dibutyl hydride in the general manner described above, aluminum-dihexyl hydride,

  aluminum-diethyl hydride, aluminum-diisopropyl hydride, the products will contain appreciable amounts of the corresponding aluminum-alkyl dihydrides. In order to carry out these reactions, the same working conditions are generally used.

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   Aluminum-alkyl dihydrides can also be prepared directly from the aluminum-trialkyl compounds but in such a case the relative proportions of metallic aluminum contacted with the feed aluminum trialkyl are appreciably increased; example up to about 2 gram atoms for an aluminum-alkyl.



   The following examples illustrate the modified process in which trialkyl aluminum, metallic aluminum and hydrogen are reacted.



   EXAMPLE XI
About 190 parts by weight of aluminum triethyl (C2H5) Al and about 11 parts of flaked aluminum are placed in an autoclave, then the autoclave is hermetically sealed and dry hydrogen admitted up to pressure. of about 250 atm. The contents are gradually heated to the operating level of about 100 - 110 while stirring during this operation. These conditions are maintained for a period of about two hours by adding more hydrogen if it is desired, and at the end of this time, the temperature of the contents of the autoclave is reduced to atmospheric level. The excess hydrogen pressure is released. A high yield of diethyl aluminum hydride (C2H5) is obtained. 2 Al H, which can be isolated by vacuum distillation.



   EXAMPLE XII
About 25 parts of finely divided metallic aluminum are introduced into an autoclave under an inert atmosphere of gaseous, dry nitrogen.



  The aluminum is prepared by grinding or filing under a dry nitrogen atmosphere. To this feed is added enough triethyl (C2H5) 3Al aluminum to thoroughly wet all the aluminum particles, or about 203 parts. The autoclave is closed and a hydrogen gas pressure of about 5 atmospheres is admitted and an additional pressure of commercially pure ethylene gas of 10 atm. The contents are stirred slowly by means of an externally controlled stirrer and the temperature rises to 80C- 85C. The contact is continued for a period of five to six hours during which the pressure is maintained in the range indicated above. At the end of this period the temperature is lowered to in- about 20 - 25 and the excess reagent is

  The empty space of the autoclave was swept with dry nitrogen gas for several cycles in order to completely remove the reactive compounds and the aluminum-tri, ethyl was recovered by distillation. A high conversion of ethyl was obtained. aluminum metallic to aluminum-triethyl approaching the stoichiometric yield of 100 parts.



   EXAMPLE XIII
The procedure of Example 12 was repeated except that the pressure of the reactive gas was increased to a partial pressure of hydrogen of about 50 atm and a partial pressure of ethylene of 100 atm. The contact time is reduced to 4 or 5 hours and a good conversion is obtained with a high yield of aluminum triethyl.



   EXAMPLE XIV
The same procedure as in Example 12 is used except that a partial pressure of hydrogen of 50 atm is used. and an ethylene partial pressure of 100 atm. The reaction temperature increases to about 125 -130 C and the contact time is reduced to about two or three hours. A high conversion to aluminum triethylo is obtained.

 <Desc / Clms Page number 13>

 
EXAMPLE XV
The procedure of Example 12 was repeated except that a hydrogen partial pressure of 290 atm and an ethylene partial pressure of 10 atm were used. At a reaction temperature of about 125-130 ° C. and a contact time of only 0.5 hours, a good conversion of aluminum metal to aluminum-triethyl is obtained.



     - EXAMPLE XVI
The procedure of Example XV is repeated except that the reaction temperature used is about 30 ° C - 40 ° C and high conversions to aluminum-triethyl are obtained over a contact time of about 20 hours.



   In the preceding examples the hydrogen-ethylene partial pressures are initially adjusted to the desired proportions by which these compounds will appear in the desired product. If the reaction pressures of the gases can be adjusted and supplied consecutively one can divide the multi-step process. This technique is illustrated by the following example.



   , EXAMPLE XVII
A reactor is charged as in Example XII, but increasing the amount of triethyl aluminum used to about 50 parts. The reaction system is subjected to an initial pressure of almost pure dry hydrogen of about 50 atm. And the reaction proceeds at about 100 ° C. for about 3 hours. The system's own pressure at the end of this period. which depends on the reactive volume, the reaction space, and the volume of the charge, would be 100 atm. at 50 atm. At the end of this treatment the temperature is reduced to 60 C - 65 C and an additional 100 atm is applied. to the reaction zone by adding gaseous ethylene.



  The contact period is extended for four hours after this time the temperature of the reaction zone is reduced to 20 ° - 25 ° C. and the excess pressure is released. A high conversion of aluminum to aluminum-triethyl is obtained. The gas pressures employed in the reactor can vary over a wide range but generally they do not exceed in the reaction zone a total pressure of about 300 atm or drop to about 10 atm. A preferred range is between 10 and 150 atm. In general, a partial pressure of hydrogen between 3 and 290 atm. Is suitable for embodiments according to the present invention.

  it is desirable to employ sufficient ethylene pressure in order to have sufficient ethylene for the reaction i.e. two moles of ethylene per mole of hydrogen to be reacted. operating at superatmospheric ethylene pressures, the range of ethylene pressures employed may vary between 100 atm. and 1 atm. about.

   A preferred range is between about 5 and 50 atmospheres, although ethylene pressures above 100 atm. can be employed when desired, their use is generally not necessary, and often undesirable because of the losses of reactive materials by numerous side reactions, i.e. the polymerization and hydrogenation of ethylene. When desired, various inert gases can be employed in addition to ethylene and hydrogen in order to give the pressure of the reaction zone a desired value while employing minimal amounts of gas. reagents.



   In this embodiment according to the invention, where a consecutive addition of hydrogen and ethylene is employed, it is often desirable to use a temperature between about 100 and 130 ° C., and in some cases,

 <Desc / Clms Page number 14>

 180 C for the first reaction phase during which only hydrogen is contacted with aluminum and aluminum-triethyl, ethylene being excluded. After the first reaction phase, and concurrently with admitting ethylene into the reaction zone, the temperature can be reduced preferably to a range of about 60 - 80 ° C in order to complete the reaction which gives aluminum-triethyl.



   From the preceding examples, it can be seen that the reaction of the present process has wide and varied application possibilities.



  It will also be apparent to those skilled in the art that a variety of common technical methods can be applied in carrying out the desired reaction. Thus, although what examples above have been described particularly for purposes of batch operations, it is evident that continuous processing types are very suitable. Thus, in cases where the primary organometallic reagent is liquid under normal conditions, it will frequently be desirable to dilute the desired amount of virgin metal with the organometallic compound and introducing it to a continuous processing zone as a dilute slurry of metal divided within the liquid organometallic compound, or it reacts with hydrogen according to various contact methods.

   An effective method of obtaining properly divided solids is to spray the metal in question in the molten state into an inert cooling liquid. Certain metals used in the embodiments of the process will be liquid under working conditions, and the foregoing particle size considerations apply to the liquid. In other words, it is very desirable to have liquid droplets entering. within the range indicated, or even finer.



   The initial readiness of the metal to be reacted is not overly critical, although it is generally found that a high degree of splitting is advantageous in that it causes a somewhat faster reaction. can initially split the metal to be reacted, by processing it in a bocard mill, or grinding it in an inert liquid and then drying it, or grinding it in a ball mill when the metal is likely to be split from this way.But particle sizes are not essential.Generally, it is better to use particle sizes smaller than 0.3mm, and preferably smaller than 0.15mm, and larger than 0.07 and preferably 0.1 mm. However, other particles, of the order of 4 mm, will frequently also be used,

   or irregular granulations.



   From the foregoing it is seen that the process is applicable to the manufacture of a wide variety and a large number of products, and that, likewise, an appreciable variety of secondary organometallic compounds can be used such as. initial reagents. Types of organometallic compounds which can be used as reactants or which can be obtained as products are as follows: lithium-ethyl, C2H5Li; lithium-n-propyl,
 EMI14.1
 nC, H7Li; potassium-ethyl, C2HlK; potassium-1-betyl, i-C4HK; potassium-phenyl, C6H5K, sodium ethyl, C2H5Na; calcium-diethyl, (C2H5) 2Ca; calcium-isopropyl hydride, i-C3H7CaH; calcium-di-n-butyl, (nC4H9) 2Ca; hydride
 EMI14.2
 magnesium-ethyl, C2H5MgH; aluminum-isopropyl dihydride, 1-C E alE; aluminum-diisopropyl hydride, (i-C3H7) 2AlH;

     beryllium-di-n-butyl (C4H9) 2Be; beryllium-diethyl, (C2H5) 2Be; beryllium-dimethyl (CH) Be,
 EMI14.3
 tin-cliethyl dihydride, (C 2 H 5) 2SnH2; tin-triethyl hydride, (GHS) SnH; etain-butyl trihydride; (C4H9) SnH3 'lithium-octyl, CsH17Li; potassium-2,2-

 <Desc / Clms Page number 15>

 dimethylpentyl, C7H1K; zinc-diisoamyl; lead-tetraethyl, lead-tetra-
 EMI15.1
 propyl, lead-tetrabutyl, lead-tetraamyl, lead-tetrahexyk, lead-tetraheptyl, lead-tetraoctyl, their isomers and mixtures thereof, etc.



  Among the bodies which the present process is very apt to produce, are included. beryllium-ethyl hydride, magnesium-isopropyl hydride, calcium-n-butyl hydride, strontium-amyl hydride, beryllium-i-butyl hydride, titanium-dimethyl dihydride , titanium-triethyl monohydride,
 EMI15.2
 titanium-i-propyl dihydride, irconium-triamyl hydride, zinc-n-butyl hydride, cadmium-amyl hydride, boron-dimethyl hydride, boron dihydride -methyl, gallium-hexyl dihydride, hydride
 EMI15.3
 gallium-dihexyl, mercury-hexyl hydride-tin-dibutyl dihydride, tin-tributyl hydride, tin-methyl-diethyl hydride, tin-dipropyl dihydride ,

   lead-trimethyl tin-triisobutyl hydride, lead-dimethyl-diethyl, lead-methyl-triethyl, lead-triethyl-propyl, lead-diethyl-dipropyl, lead-methyl-tributyl, lead- diethyl-diamyl, their isomers and mixtures thereof, lead-ethyl-triphenyl, lead-diethyl-diphenyl, lead-triethyl-phenyl, lead-tetraphenyl,
 EMI15.4
 lead-tripropyl-phenyl, lead-ethyl-trinaphthyl, lead-dibutyl-dir naphthyl, aluminum-d3.butyl hydride, aluminum-dihexy1 hydride, aluminum-diethyl hydride, aluminum-diisopropyl hydride, and d;

   other products described below.Generally, it will be noted that the metal is capable of forming an organometallic compound of reasonable stability, that is to say which can be isolated under reasonable conditions which do not deviate considerably from the conditions The individual stability of the organometallic compounds which can be obtained with the metals used varies greatly, of course, but these bodies are easily distinguished from compounds which give, at most, carbon-metal bonds. of an inorganic nature or of a merely transitory existence.

   as already stated, the reaction temperatures and pressures are susceptible to wide variations depending on the properties of the constituents of the reaction system. Thus, when the raw material is an organometallic compound of a highly reactive metal, for example an alkyl derivative of an alkali or alkaline earth metal, the hydrogenation conditions necessary to carry out the reaction are less severe than if organic compounds of metals such as, for example, those of the group III of the periodic system, especially aluminum, boron, gal- lium or indium. The reason is that the more reactive metals appear to give less stable organometallic compounds which are more easily susceptible to hydrogenation rupture. .On the other hand,

   if, for example, the initial organometallic compound is a compound such as an aluminum-trialkyl, the hydrogenation and temperature conditions are relatively strict, to carry out the reactions. In short, as indicated above, the pressures required are easy to determine and will be found to be between about 5 and 1000 atmospheres of hydrogen pressure, and at temperatures of about 25 to 200 ° C, in general, although these temperatures are not clearly limiting. The preferred pressure and temperature ranges are, in many cases, from 50 to 500 atmospheres and from 50 to 150 C, respectively, the more particularly preferred conditions for many embodiments being 100 to 250. atmospheres approximately and from 75 to 125 C approximately.

   



   The examples given here are generally discontinuous operations, which are well suited, since almost all forms of the process contemplate the initial presence of a solid metal filler. Under the reaction conditions, temperature may be high enough so that the free metal initially introduced is in the liquid phase. But in such a case, the reaction system is still, normally,

 <Desc / Clms Page number 16>

      A heterogeneous system. Batch operations are normally more convenient, but the process is not necessarily sharply limited to any particular form of reaction technique. As noted above, though. one desires continuous work, it is easy to imagine means for the appropriate circumstances.



   The reaction mechanism of the process is not fully known, and there is no question of limiting the invention to any particular explanation. However, it appears that during the reaction, the hydrogen reacts with the initial organometallic compound, releasing a free organometallic radical, which, due to the presence of free metal particles, easily reacts with it before degrading into stable and non-reactive compounds.



   The proportion of reactants in the process according to the present invention, for example the relative amounts of hydrogen and organometallic compound used, determine the proportion of organic radicals which appear in the product. When it is desired, for example, to convert In order to obtain the free or primary metal into a fully converted organometallic compound, that is, all of the valences of the metal satisfied by the carbon-metal bonds, it is desirable to use a substantial excess of the organometallic compound as initial reagent. In such a case, the ordinary course of the reaction will lead to the liberation of the metallic component of the organometallic compound in the form of a partial hydride, ie the remainder of the valences still bearing organic radicals.

   When a reaction is desired to convert the primary metal to an organometallic hydride compound, it will normally be found desirable or convenient to use the organometallic reagent in slightly reduced proportions equal to or slightly less than the stoichiometric amount necessary to give the desired compounds. Thus, by reacting approximately one molar equivalent of aluminum-triethyl with one atom equivalent of metallic lead in the presence of two molar equivalents of hydrogen and four molar equivalents of ethylene, a substantially complete conversion is achieved. to one mole of tetraethyl lead in the reaction mixture.



   However, a little less than one mole of aluminum triethyl can be used because the aluminum cycle can be repeated indefinitely in the presence of excess lead, hydrogen and ethylene.



   The amount of hydrogen should be kept in the proper stoechoometric proportions with respect to the olefin, although excess hydrogen can advantageously be used to give increased reaction pressure and hence to obtain a reaction. However, other inert gases can be used in this way, for example nitrogen, argon, helium, etc., when it is desired to use hydrogen in roughly stable amounts. compared to olefin, and at the same time achieve rapid reaction at high pressure.



   Although in general the process according to the present invention operates in the absence of a catalyst, it is sometimes preferable to use a catalyst. Among those substances which increase the rate of reaction or which can influence the distribution of the product when mixed organometallic compounds are desired, there may be mentioned iodine, alkyl iodides, metal iodides such as lead iodide, amines, ammonium salts, organic and inorganic including chloride d. ammonium and ammonium iodide, and quaternary ammonium salts such as tetraethylammonium chloride;

   aluminum compounds, especially aluminum chloride, alkyl aluminum halides, such as aluminum-ethyl sesquichloride, aluminum iodide, and the corresponding inorganic and organic compounds of polyvalent metals, including gallium trichloride; iodide

 <Desc / Clms Page number 17>

 , ferric, ferric chloride, etc.,. In general, when catalysts are used in the process of the present invention they are preferably used in amounts corresponding to about 0.01 to 1% by weight of the free metal in reaction.



   The time to produce appreciable yields by the process according to the present invention varies with the temperature and pressure applied and with the relative reactivity of the free metal, eg, lead-free, the organometallic raw material, and the olefin used. In general, in the manufacture of lead-tetraethyl, a satisfactory operation can be carried out for a reaction time of about 2 to 15 hours.



   Although the foregoing examples generally involve the use of reaction media, these media are not absolutely essential to the operation, and indeed in many cases they are undesirable and - / OR superfluous. Thus, when the organometallic compound secondary metal initially present, or the organometallic compound of the primary metal formed in the process, are liquid and relatively stable under working conditions, a reaction medium is frequently undesirable because it tends to dilute the reactants and reduces the temperature. the efficiency of the contact between the hydrogen atmosphere and the other constituents of the reaction system. Reaction media, when desired, can be selected from a wide variety of liquids,

  among which the petroleum fractions formed by solvents of the alkane type are generally considered to be the most suitable, for example hexane, mineral oil, lamp oil, naphtha, etc. Ethers are frequently used, although their use is usually avoided if one of the metals involved in the reaction is a Group IIIA metal, because of the known tendency of these metals to form complexes with simple ethers.



  Other suitable types of reaction media are ethers of polyhydroxy compounds, (although these, again, should preferably not be used with metals or compounds of Group IIIA metals), for example glycol ethers, or ethers of trihydroxyl compounds such as glycerin. In addition, types of solvents which are suitable for the present invention include tertiary amines and polyethers.



   Although the examples and descriptions given above relate mainly to the manufacture of corganometallic compounds of the primary metal, in which the substituent organic radicals, if there are several, are identical, the introduction of different radicals is, however, contemplated. on the same primary metals, such material types are zinc-propyl-butyl, tin-trimethyl-ethyl, tin-ethyl-tri-isobutyl, gallium-methyl-diethyl, magnesium-methyl -ethyl and other organometallic compounds bearing different substituents.



  Thus, by reacting a mixture of aluminum-tetramethyl, hydrogen, lead and one equivalent of propylene, the main product is lead-trimethyl-propyl. Likewise, starting with aluminum-tetramethyl first. In the absence of metallic lead and hydrogen, mixed lead compounds, methyl-ethyl, methyl-propyl, methyl-butyl, methyl-amyl, methyl-hexyl, methyl-heptyl, methyl-octyl, etc. can be obtained.

   by simultaneous reaction with ethylene, propylene, butylene, butene, pentene, hexene, oct # ne, etc ... respectively. Generally the proportions of the various alkyl radicals present in the product depend directly on the propor - stoichiometric reactions of the olefin, of the organometallic compound and of the free metal present together in the reaction mixture,

 <Desc / Clms Page number 18>

 
Organic groups of organometallic raw materials.

   are preferably lower alkyl groups, i.e. containing about 2 to 5 carbon atoms. However, organic groups of up to eight carbon atoms can also be easily treated by this method. the chain length of the organic groups increases, the reaction conditions must be carefully controlled to avoid unwanted pyrolysis and degradation.



   CLAIMS
1. Process for the preparation of organometallic compounds, in which an organometallic compound is subjected to hydrogenation in the presence of a metal.


    

Claims (1)

2. The method of claim 1, wherein the metal is the same as the metal substituent of the organometallic compound. 3. The method of claim 1, wherein the metal is loaded as divided particles passing through a 100 mesh screen and retained by a 200 mesh screen. A process for the preparation of an organometallic compound of a primary metal, wherein an organometallic compound of a secondary metal is subjected to the presence of said primary metal, the secondary metal being at a higher degree in the series of potentials of. redox than the primary metal. 5. A method according to claim 3, wherein the secondary metal is an alkali metal. 6. The method of claim 3, wherein the secondary metal is a polyvalent metal. 7. A process for preparing an organometallic compound of a trivalent primary metal. In which an organometallic compound of a divalent secondary metal is subjected to hydrogenation in the presence of the primary metal, the secondary metal being to a higher degree in the process. series of redox potentials that the: primary metal, the organometallic compound of the secondary metal being a dialkyl compound in which the alkyl groups have from 2 to 5 carbon atoms each and the hydrogenation being carried out under a pressure of hydrogen between 50 to 200 atmospheres approximately, and at a temperature between 50 and 150 Co 8. A process for preparing organo-lead compounds, in which an organo-aluminum compound is subjected to hydrogenation in the presence of lead. 9. A process for the preparation of lead-tetra-alkyl compounds, in which an aluminum-trialkyl is reacted with hydrogen and metallic lead in the presence of an olefin. 10. A process for preparing lead-tetraethyl, in which aluminum-triethyl is reacted with hydrogen, lead and ethylene. 11. A process in which an organo-lead compound is subjected to hydrogenation in the presence of lead. 12. A process for the preparation of a tetraorgano-lead compound in which a tetraorgano-lead, hydrogen, active lead and an olefin are reacted, then the obtained tetraorgano-lead compound is recovered, and the resulting compound is recovered. recycles the tetraorgano- lead mentioned at the beginning to the reaction zone <Desc / Clms Page number 19> EMI19.1 13 Process for the preparation of tetraethyl lead, in which a quantity of tetraethyl lead and hydrogen are introduced into a reaction zone containing metallic lead, and once the reaction has started, ethylene is introduced in a stoichiometric proportion and one The reaction proceeds until an appreciable amount of tetraethyl lead is formed. 14. A process for the preparation of aluminum-alkyl hydride, in which an alkylated aluminum compound having at least two substituted alkyl groups is treated with hydrogen in the presence of metallic aluminum. 15. Process for the preparation of a metal, in which at least one compound of a metal of the transition series of the periodic table is brought into contact with a compound metallic organ of a second metal, this second metal being more electropositive than the metal of the transition series. 16. The method of claim 14, wherein the alkylated aluminum compound is aluminum-triethylo. 170 A process for the preparation of triethylated aluminum, in which metallic aluminum, hydrogen and ethylene are contacted under reaction conditions and in the presence of at least a small amount of liquid aluminum-triethyl. 18. The method of claim 17, wherein metallic aluminum is contacted with hydrogen and ethylene at a pressure greater than atmospheric pressure, in the presence of at least a minor amount of aluminum. liquid triethyl and at a temperature between about 30 and 130 C. 19. The method of claim 18, wherein metallic aluminum is contacted with hydrogen and ethylene at a pressure between about 10 and 300 atmospheres. 20. The process of claim 19) wherein the reaction is carried out under a pressure of between about 10 and 150 atmospheres and at a temperature of between about 60 and 90 # C. 21. A process according to any of claims 17 to 20, wherein contact is maintained in the presence of a small proportion of liquid aluminum-triethyl for a period sufficient for the aluminum to react at least. on part of the hydrogen, ethylene is then introduced into the reaction zone and the aluminum-, triethyl formed is recovered therefrom and this low proportion of aluminum-triethyl is subsequently maintained in said reaction zone. 22. A process for the preparation of an aluminum-ethyl compound, in which disproportionate amounts of aluminum-triethyl, metallic aluminum and hydrogen are used. 23. A process for the preparation of aluminum-triethyl, wherein an aluminum-ethyl compound is first formed with disproportionate amounts of aluminum-triethyl, aluminum metal, and hydrogen under pressure. between 10 to 300 atmospheres approximately, and at a reaction temperature between 30 and 180 C approximately, and this compound is then reacted with ethylene, at a temperature between 30 and 130 C approximately, and the aluminum is recovered. triethyl thus formed. 24. Process for the preparation of aluminum-triethyl, in which metallic aluminum, hydrogen, ethylene are reacted. <Desc / Clms Page number 20> and aluminum-triethyl.