DE2341145B2 - Process for the production of aluminum - Google Patents

Description

Bringing amount of ethyl aluminum compound into the reaction.

correspond, where χ + y = 5, but can be as small as “1, and is preferably 3 to 5. (In the

indicates that the catalyst is in situ ao formula means TÄA triethylaluminum and DÄAH forms, for which one should sodium and a small amount of diethylaluminum hydride.) In summary the should

Complex catalyst used have at least one ethyl group, which of course is different from the alkyl groups the main reactants, which are propyl and isobutyl, are different.

Although the preferred catalysts, as indicated, only sodium, aluminum, alkyl groups and Contain hydrogen, halides, alkoxy groups. Cyanide or alkoxide groups partially for some of the leftovers are used.

The advantages of the invention are apparent from the detailed results given below and from FIG accompanying drawing, which graphically explains the advantages.

In practicing the invention by a preferred method of operation, an aluminum-silicon alloy is used in the form of chips or other

The present invention relates to an improved process for the production of aluminum and im a particular process stage in which alkylaluminum compounds, their alkyl groups three

their similarly comminuted particles into an autoclave together with a 50% with stirring

have up to four carbon atoms, with aluminum 40 excess over the stoichiometric amount or aluminum alloys to form the ent- an triisobutylaluminum and a small amount speaking alkyl aluminum compounds by means of a liquid sodium ethyl aluminum hydride. a well-known reaction. The autoclave is heated to 120 ° C. and pressed

In the patent 22 26 160 an overall method is to reduce it to 105 kg / cm ² with hydrogen. The total description, in which aluminum is obtained from a reaction time of 15 hours, alloy, which apart from aluminum, silicon,
Titanium, and optionally limited amounts of
Contains iron, all in controlled amounts. After this
In the process, the aluminum content is selectively implemented by treating the alloy at elevated temperatures with hydrogen and a trialkyl, a solution or dispersion of the same in a liquid aluminum compound, its alkyl group-containing medium and a liquid alkyl aluminum branch to four May have carbon atoms. binding in a reaction vessel and leads water

It has now been found that superior raw materials, with or without an olefin, can be added to the vessel to produce results can be achieved by using the aluminum compound of the corresponding alkylaluminum compound

The aluminum-containing metal to be processed should be used in any small-sized form will.

When performing the procedure one brings

a. The activation of the aluminum alloy takes place at a low temperature of around 100 to 200 ° C.
The olefins can, if desired, alpha-olefin

minium containing the alloy with alkyl aluminum compounds, hydrogen or with hydrogen
and an olefin, if desired, reacting, wherein
this reaction is sometimes called hydroalumination
designated. The improvement consists in the implementation of three or four carbon atoms, propylene, and the formation of alkyl aluminum compounds l-butene or isobutylene, with three or four carbon atoms in the alkyl groups, and these include tri-n-propyl aluminum, triisobutyl aluminum and the corresponding

The activating or catalyst agent is used in proportions of at least about 0.01% based on the aluminum content. If desired,

Alkyl hydrides, which are almost always in changing men- 65 the Akiminiummaterial with the catalyst

genes occur in the trialkylaluminium compounds, these being for example di-n-propylaluminium hydride and diisobutyl aluminum hydride.

treated before the reaction.

The mixture is thoroughly stirred during the reaction. An inert hydrocarbon or an organic

Chemical solvents such as hexane, heptane, benzene, toluene, kerosene or the like can be used.

The invention is illustrated by the following examples.

Example A.

A number of studies have been carried out to determine the effect of the various catalysts or activating agent on the yield or depletion of the aluminum-silicon alloy to be determined in the hydroalumination reaction. The aluminum-silicon alloy used contained 92 weight percent aluminum and 8 weight percent silicon and became more suitable by melting Quantities of commercially available pure aluminum and silicon prepared in a graphite crucible. The molten alloy was allowed to cool and solidify and turned out of the graphite crucible in the form of a small bar about 2.5 cm in diameter by about 5 cm in length.

The ingot was then placed in a lathe and the outer skin removed to remove any Remove carbide contaminants from the graphite crucible. Two different alloy samples A. and B with 92 Al-8 Si were used in the trials used. The actual compositions determined by fluorescent x-ray analysis (XRF) are given below in the footnotes of Tables I and II.

The hydroalumination reaction was carried out in a 300 ml autoclave with stirring, triisobutylaluminum (TIBA) being carried out as aluminum alkyl for the reaction with hydrogen at a pressure of 106 kg / cm ² at 120 ^° C. for 15 hours.

The data from the first series of experiments are summarized in Table I. It was under the following Experimental conditions worked: In a 30 ml / utoclave, which was stirred, was given:

1. 100 ml (79 g) TIBA. The same TIBA approach was used in all experiments. The diisobutyl aluminum hydride (DIBAH) is used was 8%.

2. 4.00 g of alloy A in the form of chips were tipped from an ingot with a hard metal Saw blade cut off (3.89 g for experiments 13 and 14). The chips were 1 to 2 mm wide, 2 to 4 mm long and on average about 0.1 mm thick. Each alloy charge was formed by quartered the batch sample so that the sample was representative. The TIBA to Al molar ratio was ε ^ 3, which is about a 50% excess at TIBA compared to the stoichiometric requirement.

3. A suitable amount of catalyst, sodium ethoxide, was added to Experiment 5 as a solid and added to Experiments 6 and 7 as a dilute solution in toluene. In experiments 1, 2 and 3, 5 ml of liquid sodium alkylaluminum hydride were used. This was prepared by one Natriummctal Diäthylaluminiumhydrid ¹ and containing about 70 '/ 0 DÄAH-30 "/ o TAA (triethyl aluminum) that converts the filtered and Aiuminiummetall formed. Analysis of the liquid sodium ethylaluminum hydride complex formed showed a sodium content of 8.1%.

The autoclave was _{pressure tested with H 2} gas and emptied. It was then ^{heated to 120 °} C. and charged with 106 kg / cm ² H ₂ . The pressure was held at 98.1-106 kg / cm ² for 5 hours, after which it was increased to 124 kg / cm ² . Timers were used to turn on the heater and stirrer for an additional 10 hours. Pressure maps showed that when switched off the pressure dropped to 96-106 kg / cm ² (unexpectedly). The total reaction time was 15 hours.

The reaction mixtures were worked up under nitrogen with particular care, to collect all of the solid residue. The solids adhering to the agitator were in washed off the reactor with a stream of benzene from a washing vessel. Similarly, were transfer the solids to a medium-sized fritted Buchner funnel. Of the The residue was washed well with benzene, petroleum ether, dried under vacuum for 30 minutes and weighed. The amount of aluminum reacted from the alloy was determined from the difference in weight the starting alloy and the residue weighed.

A second series of tests is given in Table II, an alloy B having a very similar composition being produced. The charge consisted of 100 ml TIBA, 4.00 g Alloy B and the appropriate amount of catalyst. The alloy was reshipped, but the fines smaller than 0.84 mm in size were removed. Furthermore, these chips were thicker than those of Alloy A and averaged about 0.15 mm. The TIBA used was the same batch as in the first run and all alloy charges were divided by dividing the batch into four. All catalyst loads were weighed, including the liquid catalyst used in Run 10. All other test details correspond to the first test series, with the exception that in this test series the heating was carried out at a pressure of 71 kg / cm ² .

The values given in Table I show that the aluminum removals obtained are dependent on both the nature and the concentration of the catalyst used. The sodium ethylaluminum hydride complex gave yields or depletions of 82 to 90 ° / Ό; if no catalyst is used, a yield of 38% is obtained. Sodium ethoxide gives a 46 to 48 per cent depletion at a low concentration, and a depletion of 68 ⁰ zo at a high concentration. Similar results are obtained in the second series of tests. The sodium ethyl aluminum hydride provides the best depletion. Sodium ethoxide, sodium fluoride and sodium diisobutylaluminum dihydride were roughly equivalent overall and gave better yields than when no catalyst was used. The lower yields of the second series of experiments are due to the use of stronger chips than were used in the first series of experiments.

Table I.

Depletion of alloy A

attempt catalyst Concentration') Residue Alloy Depletion ¹ ) No. weight loading ⁵ ) Art Vo G G Vo 1 NaH-XTAA-YDAAH .5Na 0.71 3.89 90 2 NaH-XTAA-YDAAH .5Na 0.70 3.89 90 3 NaH-XTAA-YDAAH .5Na 1.03 4.00 82 4th no catalyst 2.62 4.00 38 5 NaOAt .7Na 1.55 4.00 68 6th NaOÄt (.01 Na) ² ) 2.34 4.00 46 7th NaOÄt ! oiNa 2.27 4.00 48

') The total concentrations are given in percent by weight of the specified type of catalyst, based on TIBA,

except for experiment 6.

*) 0.01 weight percent NaOEt, based on Al in the alloy.

') Alloy A, produced with a content of 92% Al, 8 · / «Si. Analysis (XRF) 90.4 Vo Al, 71.0 Vo Si, 0.3%. Fe, 0.0 Vo Ti. *) The depletion or yields were calculated as follows:

Depletion =

Alloy charge - residue weight alloy charge ■ ° / o Al

Table II

Depletion of alloy B

attempt catalyst Concentration') Residue Alloy Depletion ') No. weight loading ² ) Art Vo G G Vo 8th no catalyst 2.97 4.00 28 9 NaOÄt 0.6 2.07 4.00 53 10 NaH XTAA-YDAAH 0.6 1.46 4.00 70 11 NaF 0.6 1.97 4.00 56 12th NaH ₂ AK-I-Bu) ₂ 0.6 1.98 4.00 56

') AUe concentrations are given as percent by weight Na, based on TIBA.

^J ) Alloy B was made with a content of 92Vo Al and 8Vo Si. Analysis (XRF) 90.8 Vo Al, 8.1 Vo Si, 0.3 Vo

Fe, <0.1 Vo Ti.
³ ) Depletions, calculated with regard to the total aluminum weight loss.

Example B.

40

Hydroaluminations of TNPA were performed with and without TAA and with and without sodium using a similar device as described in Example A. The results of the investigations are shown in FIG. 1 of the drawing explained. Curve A is the result of the hydroalumination of TNPA with and without TÄA. In the test procedures, according to which curve A was formed, the autoclave was charged with 100 ml of TNPA and 14 g of aluminum alloy, screen size less than 0.149 mm, the alloy 53.6 ^fl / o aluminum, 35.2% silicon, 4 , 6% iron and 2.0% titanium. A similar series of experiments was carried out in which 10 ml of TÄA were replaced by 10 ml of TNPA, whereby essentially the same curve as curve A was formed. Curve A therefore serves to explain two series of experiments, ie one series of experiments with 100 ml of TNPA and the other with 90 ml of TNPA and 10 ml of TAA.

Curve B illustrates the result of the hydroalumination of TNPA in the presence of sodium without TAA or any other alkyl aluminum compound. In the experiment which gave curve B , 90 ml of TNPA, 14 g of the same alloy plus 10 ml of a solution were added to the autoclave, the solution being prepared by dissolving 8 g of sodium in 100 g of TNPA and then the aluminum metal formed is filtered.

Curve C is obtained by hydroaluminating TNPA with both sodium and TAA. Curve C corresponds to the reaction in which 80 ml of TNPA, 10 ml of TÄA, 14 g of the same alloy and 10 ml of the same catalyst solution are fed into the autoclave.

In each series of tests, the autoclave was ^{pressure-tested to 71 kg / cm 2} with hydrogen and drained. The autoclave was then heated to 140 ° C and the temperature was maintained at 140 ± 1 ° C for 1 hour. The agitator was stopped and hydrogen was topped up to a pressure of 89 kg / cm ² . Stirring was then started and the pressure time curve recorded.

The invention includes all changes and changes from the examples, which merely increase Purposes of explanation have been given, insofar as the deviations from the general invention * make use of thoughts.

1 sheet of drawings

Claims (3)

Claims: It has been found that superior results are obtained when the hydroalumination process is carried out in the presence of a reaction catalyst which is a complex of an alkali metal, aluminum and alkyl groups, or alkyl groups and hydrogen, at least one of the alkyl groups being an ethyl group. Preferred catalysts include sodium triethylaluminum hydride, sodium tetraethylaluminum and sodium 1. Process for the extraction of aluminum according to Patent 2226160, characterized in that that a liquid alkylaluminum compound is reacted, the essentially tri-n-propylaluminum, tri-isobutylaluminum, di- n-propyl aluminum hydride, diisobutyl aluminum io diethyl aluminum dihydride. Preferred catalysts containing hydride or mixtures thereof, and that can, for example, of the formula one uses a catalyst which at least
contains an ethyl group. 2. The method according to claim 1, characterized in that the catalyst is characterized prepares that one sodium and a mixture of diethyl aluminum hydride and triethyl aluminum implements. 3. The method according to claim 1, characterized NaH * TÄA - yDÄAH