CZ296047B6 - Process for preparing alkali salts of 7,8-dicarba-nido-undecaborate - Google Patents

Abstract

The present invention relates to a process for preparing alkali salts of 7,8-dicarba-nido-undecarborate by degradation of 1,2-dicarba-closo-dodecarborate (o-carborate) at elevated temperature in alkaline medium wherein the preparation process is characterized in that the degradation of o-carborate is carried out at a temperature ranging from 50 to 90 degC in a heterogeneous mixture of 2 to 5 molar aqueous solution of lithium or sodium or potassium hydroxide and 8 to 16 percent by volume of heptane or toluene, in which there is dissolved 5 to 8 % percent by volume of piperidine, or diethylamine and/or primary amine having 3 or 4 carbon atoms.

Description

BACKGROUND OF THE INVENTION The present invention relates to a process for the preparation of alkali salts of 7,8-dicarbabenido undecaborate by the decomposition of 1,2-dicarbbalanco-dodecaborane (o-carborane) at elevated temperature in an alkaline environment.

BACKGROUND OF THE INVENTION

The salt of 7,8-dicarbabenido-undecaborate 7,8-C ₂ B ₉ Hi ₂ - is the starting material for the preparation of Cesium commo-3,3-cobalta-bis (1,2-dicarba-closo-dodecaborane) atu (- 1) [(C ₂ B ₉ H ₁₁ ) ₂ CO] Cs (COSAN.Cs) and its derivatives, which form the basis of prospective extraction agents of radionuclides from spent nuclear fuel elements and it is at the same time very versatile synton for the preparation of countless biologically interesting substances .

The first synthesis of 7,8-C ₂ B ₉ H ₁₂ - from 1,2-dicarbba-closo-dodecaborane C ₂ Bi ₀ Hi ₂ (o-carborane) was carried out in Wiesboeck and Hawthome anhydrous alcohol (Wiesboeck RA, Hawthorne MF: J. Am. Chem. Soc., 1964, 86, 1642). In the Institute of Anatomical Chemistry of the ASCR it was later found that the reaction was most easily carried out in methanol and that the reaction rate significantly influenced the presence of water, until it was completely stopped in 90% alcohol. With potassium hydroxide the reaction proceeds about 2 times faster than with sodium hydroxide, which in turn is about 2 times more effective than lithium hydroxide. The reaction proceeds according to equation (1):

C ₂ B ₁₀ H ₁₂ + 2MOH CH 2 OH ». (C ₂ B ₉ H ₁₂ ) M + MOBO + H ₂

An alternative route is the degradation of o-carboran by secondary amines according to equation (2):

C ₂ B | ₀ H ₁₂ + 3 R ₂ NH benzene (C ₂ B ₉ H ₁₂ ) H ₂ NR ₂ + (R ₂ N) ₂ BH + H ₂ (2) (Zakharkin LI Kalinin VN: Tetrahedron Lett. 1965, 407). In this case, a slurry of solids in benzene is formed. Subsequent solvolysis, e.g. with ethanol, decomposes the bis dialkylamino borane into hydrogen, the boronic ester and releases the dialkylamine used. Some primary amines and especially hydrazine are also effective.

However, both processes are relatively disadvantageous and expensive for large-scale synthesis of COSANs. In the first case, a large amount of anhydrous alcohol is consumed, in the second case it is necessary to convert primary ammonium salts to alkaline salts - and in both cases there is a great problem not only of removing all cosolvents, but also their virtually economically impracticable recovery and subsequent disposal problems.

Both of these disadvantages are overcome by the new manufacturing method according to the invention.

SUMMARY OF THE INVENTION

SUMMARY OF THE INVENTION The present invention provides a process for the production of alkali salts of 7,8-dicarbabenido-undecaborate by degradation of 1,2-dicarbbalancedododecaborane (o-carborane) at elevated temperature in alkaline

The environment according to the invention is characterized in that the degradation of the o-carborane is carried out at temperatures of 50 to 90 ° C in a heterogeneous mixture of a 2 to 5 molar aqueous solution of lithium, sodium or potassium hydroxide and 8 to 16% by volume of heptane; toluene in which 5-8% by volume of piperidine or diethylamine and / or a primary amine with 3 C or 4 C is dissolved.

Preferably, n-butylamine dissolved in toluene can be used as the primary amine.

The preparation of the salts of the 7,8-dicarbabenido-undecaborate according to the invention takes place in the organic layer of the heterogeneous mixture, while the alkaline aqueous layer serves to continuously regenerate the amine and convert the ammonium salt to the alkali salt. Thus, the reaction proceeds at an almost constant rate. Upon completion of the reaction, the organic layer contained virtually all the amine and traces of unreacted o-carboran, but also no C2B9H12M salts, which were easily extracted from the aqueous layer into a solution of the amine in toluene. Therefore, it is preferable to distill out all the auxiliaries at normal pressure as azeotrope after the reaction (the boiling point of the toluene / water azeotrope is e.g. 85 ° C and contains 0.975 mol of toluene and 1.120 mol of water). The distillate is used as the degradation medium in the following batch. The remaining alkaline aqueous solution can be used without further treatment to further synthesize COSAN.

This represents a significant simplification of the technology. The advantages can be summarized as follows: a) there is no need to prepare anhydrous alcohol, b) there is no lengthy vacuum distillation of alcohol, addition of water and new distillation, so that the reaction mixture does not contain residual alcohol and no regeneration thereof, c) no water is needed except water and alkaline hydroxide other solvents, except for a small amount of heptane or toluene and the corresponding amine, but which are constantly recycled; d) the rate of reaction can be controlled by the choice of the amine and its initial amount; e) the Li, Na or K salt is prepared as easily.

This makes the production technology waste-free and environmentally friendly. This production process should generally be applicable to all o-carborane derivatives.

DETAILED DESCRIPTION OF THE INVENTION

The invention is further illustrated by the following examples.

Example 1

In a 250 ml round bottom flask equipped with a magnetic stirrer, reflux condenser and dosing adapter was added 100 ml of water, in which 17 g of KOH (300 mmol), 10 ml of toluene and 5 ml of piperidine (50 mmol) were dissolved and 14 ml. 5 g of o-carborane (100 mmol). The reaction mixture was heated with stirring at 90 ° C for 6 hours (cessation of hydrogen evolution). Without vacuum, toluene and piperidine were distilled off with some water (ca. 30 ml). This distillate is useful for the next operation after making up to 100 ml with water and adding new o-carborane and KOH. The product was pure C ₂ B ₉ Hi ₂ - by TLC in min. 99%, determined by gravity using Ν (ΟΗ ₃ ) ₄ - salt precipitated from the measured portion of the solution. The prepared solution can be used directly for the synthesis of COSAN.

Example 2

The apparatus of Example 1 was charged with 100 mL of water in which 12 g of NaOH (300 mmol), 10 mL of piperidine (100 mmol) and 20 mL of heptane were dissolved and 14.5 g of o-carborane (100 mmol) were added. The reaction was complete in 3 hours. After distilling off piperidine, heptane and about 30 ml of water, a solution of the product suitable for the synthesis of COSAN was obtained. The reaction yield was min. 99%.

-2GB 296047 B6

Example 3

To the apparatus of Example 1 was added 100 ml of water, in which 12 g of NaOH (300 mmol), 15 ml of n-butylamine and 10 ml of toluene were added, and 14.5 g of o-carborane (100 mmol) were added. The reaction mixture was stirred at 80 ° C. After 1 hour, o-carborane was not found in the reaction mixture by TLC. The reaction was complete after 2 hours. Without stirring under stirring, the toluene / n-butylamine azeotrope was distilled off and the distillation was terminated at 100 ° C in the vapor phase. The heterogeneous distillate was used to break down further o-carboran (after adding water to 100 ml, adding 12 g of NaOH and 14.5 g of o-carboran), while the hot aqueous solution of C ₂ B9Hi ₂ salt was used directly after distilling the azeotrope. for the synthesis of COSAN.Na (yield of this whole 2 step synthesis was 82.5%).

Industrial applicability

The process according to the invention can be used in the chemical industry, for example, in the preparation of extraction agents for radionuclides and in general all compounds for which the anion nido-7,8-C ₂ B ₉ Hi ₂ "precursor.

Claims (2)

A process for the production of alkali salts of 7,8-dicarbabenido undecaborate by degradation of 1,2-dicarbacloso-dodecaborane or o-carborane at elevated temperature in an alkaline medium, characterized in that the degradation of o-carborane is carried out at temperatures of 50 to 90 ° C in a heterogeneous mixture of a 2 to 5 molar aqueous solution of lithium or sodium or potassium hydroxide and 8 to 16% vol. Of heptane or toluene in which 5 to 8% vol. Of piperidine or diethylamine or a primary amine with 3 C or 4 C. 2. The process of claim 1 wherein the primary amine is n-butylamine dissolved in toluene.