DE1175233B - Process for the electrolytic production of organic lead compounds - Google Patents

Description

FEDERAL REPUBLIC OF GERMANY GERMAN -WM ^ PATENT OFFICE

EDITORIAL

Boarding school Cl .: C07f;

BOIk
German: 12 ο -26/03

Number: 1175 233

File number: E19443IV b / 12 ο

Filing date: June 9, 1960

Opening day: August 6, 1964

The invention relates to a method for the electrolytic production of organic lead compounds using a lead anode and an organoboron complex as electrolyte, which is characterized is that one uses water as a solution medium for the electrolyte. To be favoured such organoboron complexes used, whose anion consists of a boron atom, which is only attached to carbon Hydrocarbons is bonded, of which at least one of a lower alkyl radical with up to consists of about 8 carbon atoms, especially the ethyl radical, and their cation consists of an alkali ion, especially sodium. The electrolysis can take place at temperatures up to the decomposition temperature of Electrolyte and organic lead compound are carried out. Even if the one according to the invention The electrolyte used in the process has excellent conductivity is sometimes an improvement its conductivity is desirable through the addition of ionizable salts. Among the preferred added, Ionizable salts include the sodium and potassium halides.

The method according to the invention is superior to the known methods in several ways. For example becomes the organic lead product with high yield and purity with little power consumption won. A particular advantage of the new process is that water is used as the solvent used and thereby a system of higher conductivity is created. Another benefit of the Method is that the boron metal is not deposited on the cathode, as with Aluminum and zinc when using the alkyl zinc or alkyl aluminum compounds as electrolytes the case is. In the process according to the invention, there is therefore no need for the difficult separation of Boron from the cathode and the associated difficulties in processing and Reuse of this boron for electrolyte production or other purposes. Another advantage of the invention is that simpler processes for reprocessing the electrolyte available, some of which are detailed below. Another advantage of the invention Process consists in the fact that higher efficiencies and higher conductivities can be achieved in the production of organic lead compounds are.

The boron anion of this complex contains groups bonded to boron, at least one of which consists of a hydrocarbon radical bonded via a carbon atom and having up to about 30 carbon atoms. Process for electrolytic production
of organic lead compounds

Applicant:

Ethyl Corporation, New York, N.Y. (V. St. A.)

Representative:

Dr. phil. G. Henkel, Baden-Baden-Balg,
and Dr. rer. nat. W.-D. Handle,
Munich 9, Eduard-Schmid-Str. ^Y 2,
Patent attorneys

Named as inventor:
Richard Coleman Pinkerton,
Baton Rouge, La. (V. St. A.)

Claimed priority:

V. St. v. America June 23, 1959 (822 215)

consists and the rest of halogen, hydrogen, alcohol residues (-OR) with up to about 18 carbon atoms, Pseudohalides, from organic acid anions with up to about 18 carbon atoms or inorganic anions can exist. The cationic portion of the organoboron complex exists generally from an alkali or alkaline earth metal ion or ammonium. The organic boron complexes can be represented by the following formula:

M (BR ¹ R ² R ³ R ⁴ ).,

in which R ¹ , R ² , R ³ and R ⁴ consist of the groups described above with respect to the boron anion of the complex and y is 1 or 2. Such complexes are usually prepared in such a way that a BR ¹ R ² R ³ compound is reacted with an M (R ⁴ ) ^ .- compound, where R ¹ , R ² and R ³ are as defined above, and M as described above Means cation and χ is equal to the valence of the metal.

In some cases an advantage is obtained by having one of the groups bonded to boron from consists of an alkyl radical with up to 8 carbon atoms and the three other groups are alkyl radicals with up to about 30 carbon atoms are, as a result

409 639/434

i 175 233

a lower-melting electrolyte obtained and the separation of the by-product Organoboron compound is facilitated by the organic lead compound produced at the anode. A similar Effect is achieved when the other three groups consist of branched-chain alkyl radicals, such as isopropyl or isobutyl. Typical examples of these preferred complexes are sodium ethyl trioctylboranate, Sodium ethyl tricyclohexylboranate, sodium ethyl tributylboranate, sodium ethyl triisopropylboranate, Sodium ethyl triphenylboranate and sodium ethyltrioctadecylboranate called.

It goes without saying that mixtures of the aforementioned organoboron complexes are also like a mixture from sodium tetraethylboranate and potassium tetraethylboranate can be used. Other useful mixtures consist for example of Natriumäthyltriphenylboranat and Kaliumtetraäthylboranat as well from sodium ethyl triphenylboranate and potassium ethyl triphenylboranate. When making such mixtures all that matters is that two or more complexes are miscible with one another.

It can be advantageous to add an ionizable salt to the organoboron complexes, because it does this in general, the conductivity of the electrolyte is increased. The main condition for such ionizable salts consists in the fact that they under the electrolysis conditions with the organoboron complex go into solution or deal with it with the formation of a complex or complex mixture specified Implement Art. The alkali and alkaline earth halides and pseudohalides are especially useful for this purpose suitable.

The proportions of the electrolyte components are generally variable within a fairly wide range. In cases in which an ionizable salt is added to the organoboron complex, the proportion can be between about 0.01 and 50 mole percent. The amount of water used is general between that which is just sufficient to dissolve the electrolyte up to about five times Amount thereof.

The electrolysis can be carried out in various ways, but generally requires only the installation of an electrolytic cell with at least one lead anode and a corresponding one Number of suitable cathodes and the input of the electrolyte or its solution. After that, the The cell is heated to the desired operating temperature and electricity is passed through it. During electrolysis further electrolyte can be topped up to replace it, and the organic lead compound is removed from the Peeled off the anode area of the cell. If the anolyte consists of a mixture of the organic lead product and By-products and / or water consists, it is separated according to the usual physical separation methods worked up. In many cases the desired organic lead compound is not compatible with the other system components miscible and can then be removed from the cell in practically pure form. Other Embodiments of the electrolytic process require regeneration, for example of the electrolyte, which will be described in more detail below.

The electrolysis process according to the invention is further illustrated by the following examples: in which all parts are by weight unless otherwise specified.

example 1

An electrolytic cell with a lead anode and a copper cathode was made with 0.432 parts of sodium tetraethylboranate in the form of diethyl ether and 40 parts of water and filled after sealing charged with a current of 10 mA for a total of 3 hours and 53 minutes. During electrolysis Tetraethyl lead formed and collected ίο easily removable on the cell floor. At the end the electrolysis, tetraethyl lead was obtained in 100% yield.

Example 2

Example 1 was the p _H -value of the aqueous solution repeated using Natriumtetraäthylboranat in the form of the diet Herat of Diäthylenglykoldimethyläthers instead of Diäthylätherats and increase by slight addition of alkali 12, and electrolysis carried out at room temperature for 3 hours, whereby the yield of tetraethyl lead 88, 2%.

To further increase the conductivity, even larger amounts of alkali metal hydroxide, up to about 40 percent by weight of the water present can be used.

In a preferred procedure, the electrolysis is carried out at temperatures between about 70 and HO ⁰ C, because the conductivities are then higher. The application of pressure is not necessary unless the work is carried out above the boiling point of the electrolyte components or the product. Autogenous pressure can be used in general and in particular when the electrolysis is not combined with an in-situ work-up of the electrolyte of the type described below.

The voltage applied to the cell is generally up to about 50 V, but is preferably below about 10 V. The current is usually above 10 mA / cm ² for practical reasons and is preferably below 1 A to avoid excessive localized heating and short circuits / cm- 'held.
It is also often advantageous to use chamber cells, ie to insert a diaphragm between the anode and cathode in the usual way in other electrolysis processes.

The cathode can consist of a conductive material that is practically neutral to the electrolyte used. For example, in addition to copper, platinum, nickel, tungsten or nickel-carbon alloys can be used. The cathode can also consist of lead.
The basic electrolyzing process described above is well suited for combination with electrolyte regeneration. Such an electrolyte regeneration process consists of an in-situ process in which hydrogen and a suitable olefin are kept as the atmosphere in the cell or, better still, are introduced into the electrolyte surrounding the cathode. Hydrogen and olefin can be added simultaneously or one after the other, for example by alternately introducing hydrogen and then olefin in each case until nothing is absorbed anymore, as can be seen from the pressure drop, and this change is repeated during the electrolysis. In the case of an alternating feed, the row

follow the other way round, i.e. first olefin and then hydrogen are added in the manner indicated. In this embodiment, the method consists in passing a current through the lead metal and to send the organobor complex through to the cathode and at the same time the hydrogen and / or to introduce the olefin into the cathode region in the manner described.

In carrying out this procedure, the conditions described above with respect to simple electrolysis are used. In the starting electrolyte, however, a boron compound BR ¹ R ² R ^{3 is added} in an amount of - calculated on 1 mole of organoboron complex - about V20 to 1 mole, where R ¹ , R ² and R ^{3 have} the meaning given earlier and the compounds are preferably the boron compound formed together with the organic lead product at the anode are analogous. For example, if a boron halide is generated at the anode in addition to the organic lead, the original addition will be a boron halide. Similarly, in the electrolysis of sodium tetraethyl boronate, triethyl boron is initially added to the electrolyte.

The olefins used are those consumed during electrolysis for the formation of organic lead products Hydrocarbon radical analogous. For example, in the manufacture of tetraethyl lead So the used olefin from ethylene. Because of their easier availability and usability in the regeneration process, the terminally unsaturated olefins with up to about 8 carbon atoms particularly preferred.

Claims (5)

Patent claims: 1. Process for the electrolytic production of organic lead compounds using a lead anode and an organoboron complex as electrolyte, characterized in that, that one uses water as a solution medium for the electrolyte. 2. The method according to claim 1, characterized in that the conductivity of the Electrolytes increased by dissociable salts. 3. The method according to claim 1 or 2, characterized in that the organoboron complex is used Sodium organoboranate used. 4. The method according to claim 1 to 3, characterized in that the electrolyte during the electrolysis in a manner known per se by supplying olefin and hydrogen in the vicinity of the cathode is regenerated. 5. The method according to claim 1 to 4, characterized in that the cathode recovered deposited metal and reacts with hydrogen that is formed at the anode Separating organic lead compound with the boron compound formed as a by-product, this boron compound reacts with the metal hydride to form a complex and it with one of the consumed in the formation of the organic lead compound Brings organic groups corresponding olefin to the reaction. Considered publications:
British Patent No. 797 093.