DE1216301B - Process for the preparation of alkyl compounds of the elements Sn, Pb, As, Sb and Bi - Google Patents

Description

Process for the production of alkyl compounds of the elements Sn, Pb, As, Sb and Bi It is known to use organometallic compounds according to O r i g n a r d to manufacture. While this method works well in the laboratory, it is hers Difficult to carry out on an industrial scale. Therefore one already has alkyl mercury halides from mercury halides by reaction with organoaluminum compounds manufactured. It is also known to carry out boron trialkyl compounds from boron trifluoride Reaction with alkylaluminum halides to produce, the alkyl radical being any Chain length can have.

Finally, it should be mentioned that, according to patent 977 309, fluorides are also used of Zn, Cd, Hg, Sn, P, As and Sb with the help of organoaluminum compounds has converted into the alkyls of the elements mentioned.

It has been found that organoaluminum compounds are also used for Replacement of halogen by alkyl groups in other metal chlorides, bromides or -iodides are suitable. Implementations of this type have so far been carried out with Grignard compounds, organic zinc or organic alkali compounds.

The present invention relates to a method of production of alkyl compounds of the elements Sn, Pb, As, Sb and Bi, which is characterized is that the chlorides, iodides or bromides of the elements mentioned with organoaluminum Reacts compounds of the type Alu3, AlR2Hal, AlRHal2 or Al2R3Hal3, in which R in each case denotes an alkyl radical and Hal denotes C1, Br or J.

In general, this is the use of alkyl aluminum sesquichlorides (AlaR3Cl3) the most economical, as these are the easiest to manufacture, at least when R = CH3 or C2H5. If R is to be a higher alkyl group, it is advisable to Use aluminum trialkyl compounds.

It was not to be expected that the chlorides, iodides or bromides of the Elements Sn, Pb, As, Sb and Bi can be alkylated by means of organoaluminum compounds be; because it is known to the person skilled in the art that in mercury compounds both in with respect to halogen and also to alkyl radicals, special bond ratios, namely few polar bonds are present, the stability of which makes the production of alkyl mercury halides relieved.

It was the same with knowledge of the above-mentioned reaction of boron trifluoride it is not to be expected that the organometallic compounds of the elements will be higher Can produce atomic weight in such a simple way.

The reactions with organoaluminum compounds bindings run fundamentally analogous to the known procedures. One can use the organoaluminum alkylating agent exploit in all cases until it is converted into aluminum trihalide, however it is often convenient to use an excess of alkylating agent. Generally The following equations apply: 3 MeHaln t nAIR3 + 3 MeRn t nAlHal3 2 MeHal, t AlR2Hal + 2 MeRn t nAlHal3 MeHaln + nAlRHal2 + MeRn t nAlHal3 3 MeHaln t nAl2R3Hal3 + 3 MeRn + 2n AlHal3 Herein Hal and R have the above meaning.

For some elements, the alkylation proceeds exclusively according to these Equations up to the replacement of all halogen atoms by an alkyl group. With others Elements it is possible to produce halogen-containing metal alkyl compounds if accordingly fewer organoaluminum compounds are used. As an an example the preparation of the alkyl tin compounds is mentioned.

The use of methylene chloride as a solution or. Suspending agent is particularly advantageous in carrying out the instant reaction. One works then expediently at temperatures between 0 and 42 ° C. The solutions of the organoaluminum Alkylating agents in this solvent are without special precautions to handle, because the vapor pressure of the methylene chloride at ordinary temperatures offers adequate protection against atmospheric oxygen. Also is methylene chloride unlike any other in question indifferent solvents, d. H. mainly hydrocarbons, non-flammable, what when working with the spontaneously flammable aluminum organic substances is beneficial.

In general, the solid halides are converted, such as PbCl2 or BiCl3 advantageously as a suspension in an inert solvent, preferably in methylene chloride; the soluble halides become advantageous in such Solvent dissolved.

However, the reactants can also act directly on one another let, e.g. B. if you carefully the metal halides in the Al-alkyl compounds stirs in.

You can also start the reaction in a solvent first, the latter then distill off and the reaction at higher temperatures, e.g. B.

80 to 100 "C, complete in the absence of solvents.

The separation of the desired process product from the resulting Aluminum trihalide or the unreacted excess organoaluminum Connection can be made by decomposing the aluminum compounds with ice or water, because the desired compounds are resistant to water or dilute acids.

The organotin compounds are easiest to work up since you only have to add water to the reaction solution, the aluminum trihalide and the excess alkylating agent is hydrolyzed and in the aqueous Phase go into solution. The separated organic phase is dried and the Solvent distilled off from the organotin compound. This will eventually purified by distillation.

It is possible to control the reaction itself by choosing the amount of said To control alkylating agent so that one of the compounds of the type SnRHal3, SnR2Hal2, SnR3Hal or SnR4 is practically the only product that is created. Proceeds more expediently however, by using the alkylating agent in excess, that is now analyzed and alkylated products beyond the desired alkylation stage by briefly heating with the calculated amount of tin tetrahalide immediately the pure product of the desired alkylation stage is obtained.

The tin compounds are stabilizers in plastics chemistry and are intermediate products for pesticides containing tin.

Also the organic lead compounds of tetravalent lead are resistant to water and air.

If one starts with lead (II) halides and the lead (II) -aWyl compound necessary amount of aluminum alkyl halide, then disproportionation of the occurs bivalent to tetravalent lead and metal one; 2 PbCla + 2 Al (C2H6) 2Cl = 2 AlC13 + Pb + Pb (C2H5) 4 In this way, halogen-containing substances are never produced Lead alkyl compounds.

In general, one works in such a way that the finely powdered lead (II) chloride is used suspended in an inert solvent and the solution of the alkylating agent lets run in with stirring. If you want to produce tetraalkyl lead, it is advisable to to work at higher temperatures, e.g. B. in boiling cyclohexane, so the reaction time is abbreviated. This is where disproportionation leads of what is undoubtedly the first to arise Dialkyl lead completely to tetraalkyl lead.

Obtaining the first in solution together with aluminum trichloride or tetraalkyl lead formed with alkyl aluminum chlorides takes place in the same way in the tin compounds. The resulting elemental lead is very fine-grained and can be used for reactions of lead that require fine distribution will. So you can at the same time alkyl chloride, z. B. ethyl chloride, initiate and the resulting lead z. B. in the presence of the alkylating agent in Convert Pb (C2H5) 3Cl: 2 Pb + 4 C2H5Cl + Al (C2H5) 2Cl 2 Pb (C2H5) 3Cl + AlCl3 Man can also produce compounds that contain various alkyl radicals.

Arsenic trihalides settle, preferably dissolved in methylene chloride, very lively with organoaluminum compounds. This implementation leads to Arsenic trialkyl compounds, but not to alkyl arsenic dihalides, which are known to be used can be obtained by alkylation with mercury dialkyl compounds. The extraction the arsenic trialkyl compounds happen, for. B. by decomposition of the resulting at the same time Aluminum compounds using ice and distillation in the absence of air.

There is one each of the trivalent and pentavalent antimony Range of stable halogen compounds. Both series react with organoaluminum Compounds with the replacement of 3 halogen atoms by one alkyl group each, so that the antimony trialkyl compounds are obtained from the antimony trihalides and the antimony pentahalides the trialkylantimony dihalides.

In the bismuth trihalides, all 3 halogen atoms become organoaluminum Compounds replaced by alkyl groups. One works expediently in such a way that one can finely powdered bismuth halide suspended dry in an inert solvent and flowing in a solution of said alkylating agent. The reaction leaves accelerate by heating and is finished when all bismuth halide has reacted is. Since bismuth trialkyl compounds are insensitive to water, they are also decomposed resulting aluminum compounds by adding air-free water and distilling the solvent is removed from the separated, non-aqueous phase. The bismuth trialkyl compounds remain behind and are in the absence of oxygen by vacuum distillation cleaned.

Example 1 Tetraethyltin SnCl4 + 2 Al (C2Hj2Cl Sn (C2H5) 4 + 2 AlCl3 In a solution of 550 g of aluminum ethyl sesquichloride in 11 methylene chloride with stirring 500 g of tin tetrachloride added dropwise so quickly that the on the flask attached reflux condenser the heat of reaction by condensation of the evaporating Can remove methylene chloride. The methylene chloride is then distilled off and the contents of the flask were kept at 100 "C for 4 hours.

After the methylene chloride has gone back, the reaction product is with Ice and hydrochloric acid are added, the organic phase is separated off and washed with water. By shaking with potassium fluoride solution becomes some triethyltin chloride deposited. The remaining solution of tetraethyltin becomes the methylene chloride distilled off and the tetraethyltin then purified by distillation.

Kr.13 = 78 "C, yield 360 g.

Example 2 triisobutyl tin chloride In a solution of 240 g of tri (isobutyl) aluminum in 0.5 1 of methylene chloride, 260 g of tin tetrachloride are added dropwise with stirring in the same way as in Example 1. After the methylene chloride has been distilled off, the contents of the flask are kept at 100 ° C. for 3 hours, then If, after returning the methylene chloride, ice and hydrochloric acid are added, the separated methylene chloride phase is dried and the solvent is distilled off. The residue is distilled in vacuo (at 13 torr from 140 to 145 ° C.).

245 g of a liquid are obtained, the analysis of which has a chlorine content of 9.7 0! o and that by briefly heating with 7 g of tin tetrachloride in pure Triisobutyltin chloride is transferred.

Example 3 Tetraethyl lead 2 PbCl2 + 2 Al (C2H5) 2Cl Pb + Pb (C2H5) 4 + 2 AlCla 278 g of finely powdered lead (II) chloride are dissolved in 0.5 l of methylene chloride suspended. 140 g of diethylaluminum chloride are added to the boiling liquid while stirring. dissolved in 300 cc of methylene chloride, drop in. After 10 hours at 42 "C, everything is there Lead chloride reacted to form a suspension of black metallic lead. The supernatant liquid is transferred to another flask, the existing one Aluminum compound decomposed with ice and hydrochloric acid and the methylene chloride phase dried.

After distilling off the methylene chloride by vacuum distillation 120 g of a liquid boiling at 13 torr and 80 to 84 ° C. was obtained.

Lead deposition occurs during distillation, which indicates a content of Hexaäthyldiblei indicates.

After another distillation, 100 g of pure tetraethyl lead are obtained obtain.

Example 4 Triethyl arsenic To a solution of 150 g of diethyl aluminum chloride in 0.5 1 of methylene chloride is left under Stir a solution of 121 g of arsenic trichloride at 40 ° C pour in 0.2 l of methylene chloride in the course of 30 minutes. The reaction solution is kept at 42 ° C. for 2 hours, cooled, and ice is carefully added The methylene chloride phase is dried over calcium chloride and the methylene chloride is distilled off.

Triethyl arsenic remains, which is purified by distillation will. 80 g are obtained, b.p. = 140 to 142 "C.

Example 5 Triethyl bismuth BiJ3 + Al2 (CH5) 3Cl3 Bi (C2H5) g + AlCl3 + AlJ3 To a suspension of 100 g of dry, powdered bismuth iodide in 300 ccm 50 g of ethylaluminum sesqnichloride are added to methylene chloride.

After 9 hours of heating at 42 ° C. with stirring, all of the bismuth iodide is present implemented. The existing aluminum compounds are slowly added dropwise decomposed by water under nitrogen blanketing, the methylene chloride solution becomes drained and dried. After the methylene chloride has been distilled off, the product becomes distilled in vacuo with a nitrogen blanket.

At 30 Torr and 95 to 98 "C, 27 g of triethyl bismuth pass over.

Example 6 Triethylantimony dichloride 2 SbCl5 + 3 Al (C2H5) 2Cl = 2 Sb (C2H5) 2Cl + AlCl3 To a solution of 189 g of diethyl aluminum chloride in 0.5 1 of methylene chloride 300 g of antimony pentachloride are added dropwise at 42 "C. with stirring over the course of 90 minutes. The reaction solution is mixed with ice and washed with water until in the organic Phase no more precipitation occurs.

After filtering and drying the solution and distilling off 100 g of triethyl antimony dichloride remain behind of the methylene chloride in the vacuum of the water jet pump as weakly colored 01.

Claims (1)

Claim: Process for the preparation of alkyl compounds of Elements Sn, Pb, As, Sb and Bi, d u r c h g e k e II n z e i c h n e t that the chlorides, iodides or bromides of the elements mentioned with organoaluminum Reacts compounds of the type Alu3, AlR2Hal, AlRHal2 or Al2R3Hal3, in which R in each case is an alkyl radical and Hal is Cl, Br or I. Older patents considered: German Patent No. 977 309.