RU2378195C1 - Decahydro-closo-decaborate anion sythesis method - Google Patents

Abstract

FIELD: chemistry.

SUBSTANCE: invention can be used in synthesis of a decahydro-closo-decaborate anion (B₁₀H₁₀ ^2-), the salts of which are used in nickel electroplating metal objects. Said anion is obtained by taking a solution of sodium undecaborate NaB₁₁H₁₄ in diglyme. Tributylamine is added and the obtained solution is boiled at 160°C for 1 hour until the yellow colour of the solution disappears. After that the reaction mixture is cooled to room temperature. Water and glacial acetic acid are added, obtaining a precipitate of tributylammonium decahydro-closo-decaborate, which is then filtered, washed with water and dried in air.

EFFECT: increased output and purity of the end product, avoiding use of decaborane during synthesis.

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Description

The present invention relates to methods for producing an anion of decahydro-closo-decaborate B ₁₀ H ₁₀ ^2- , the salts of which are used as reducing electrolytes in electrolytic nickel plating of metal products.

A known method of producing decahydro-closo-decaborate, where as the starting components for the production of decahydro-closo-decaborate In ₁₀ N ₁₀ ^2- are used sodium borohydride (NaBH ₄ ) and triethylamine borane (C ₂ H ₅ ) ₃ NBH ₃ . In the course of the chemical reaction, in addition to decahydro-closo-decaborate, two other closo-borates are formed [(MVPechersky, VABrattsev, MGKuznetsova, et al., EUROBORON-4, 159, 2007)]:

The disadvantages of the known method for producing decahydro-closo-decaborate are the low yield of the main product, which is about 20-25%, as well as the need for its isolation from a three-component mixture.

The closest in technical essence to the claimed method, selected for the prototype, is a method for producing decahydro-closo-decaborate (B ₁₀ H ₁₀ ^2- ) by the interaction of decaborane (B ₁₀ H ₁₄ ) or its complexes with triethylamine (J. Dupont, M. Hawthorne , A. Petochelli, R. Ettinger, J Am. Chem. Soc., 84, 1057, 1962):

The disadvantage of this method is the expensive and inaccessible feedstock - decaborane, necessary for the implementation of the process.

The problem solved by the claimed technical solution is to create a new simple way to obtain decahydro-closo-decaborate with high yield and high chemical purity of the target product.

The problem is solved due to the fact that in the inventive method for producing decahydro-closo-decaborate, sodium undecaborate (NaB ₁₁ H ₁₄ ) obtained by the method of [G. Dunks, K.Barker, E. Hedaya et al., Inorg . Chem., 20, 1692 (1981)], and tributylamine.

A mixture of the starting reagents dissolved in diglyme is heated to a temperature of 160 ° C; as a result of the reaction, decahydro-closo-decaborate and tributylamine borane [(C ₄ H ₉ ) ₃ NVH ₃ ] are formed. Tributylamine borane is precipitated as [(C ₄ H ₉ ) ₃ NH] ₂ B ₁₀ H ₁₀ , and the obtained decahydro-closo-decaborate is isolated from the reaction mixture.

The yield of decahydro-closo-decaborate reaches 90%.

The inventive method is confirmed by the following examples:

Example 1

Obtaining sodium undecaborate (NaB ₁₁ H ₁₄ ) in diglyme.

В двухлитровую трехгорлую колбу, снабженную мешалкой, термометром, коротким обратным холодильником с газоотводной трубкой и капельной воронкой, загружают 400 мл безводного диглима и 60 г (1,58 моль) боргидрида натрия NaBH₄. Смесь продувают аргоном и при перемешивании нагревают до температуры 105°.

400 ml of anhydrous diglyme and 60 g (1.58 mol) of sodium borohydride NaBH ₄ are charged into a two-liter, three-necked flask equipped with a stirrer, a thermometer, a short reflux condenser with a gas tube and a dropping funnel. The mixture was purged with argon and heated to 105 ° with stirring.

Then, at a temperature of 105 ° C., 240 ml (1.89 mol) of BF ₃ OEt _{2 are} added dropwise from the dropping funnel over 6 hours. After completion of the introduction of BF ₃ OEt ₂ with slow passing of argon and stirring, the reaction mass is kept at a temperature of 105 ° С for 2 hours, then it is cooled to a temperature of 60 ° and filtered through a thick glass filter, the precipitate of NaBF ₄ on the filter is washed twice with absolute diglyme ( 50 ml).

The obtained filtrate - a solution of sodium undecaborate is further used in the synthesis of decahydro-closo-decaborate (B ₁₀ H ₁₀ ^2- ).

Example 2

Obtaining tributylammonium decahydro-closo-decaborate [(C ₄ H ₉ ) ₃ NH] ₂ B ₁₀ H ₁₀

In a one liter three-necked flask pre-purged with nitrogen, equipped with a stirrer, reflux condenser and thermometer, a solution of sodium undecaborate (90 mol) obtained from 30 g of sodium borohydride in 200 ml of diglyme is added, 40 g (216 mol) of tributylamine are added, the resulting solution is boiled at 160 ° C for 1 hour until the yellow color of the solution disappears. After this, the reaction mixture is cooled to room temperature, then 500 ml of water and 100 ml of glacial acetic acid are added, and [(C ₄ H ₉ ) ₃ NH] NaB ₁₀ H _{10 is} converted to tributylammonium decahydro-closo-decaborate, which precipitates. The precipitated crystalline precipitate is filtered, washed with water and dried in air. The yield of crude tributylammonium decahydro-closo-decaborate is 39.8 g (90% based on NaB ₁₁ H ₁₄ ). The resulting tributylammonium decahydro-closo-decaborate is dissolved in 30% acetic acid, recrystallized and dried in air. 35.8 g of the expected product are obtained. The total yield of tributylammonium decahydro-closo-decaborate is 80%.

Example 3

Obtaining decahydro-closo-decaborate potassium (K ₂ In ₂₀ N ₁₀ ).

32 g (65 mol) of tributylammonium decahydro-closo-decaborate [(C ₄ H ₉ ) ₃ NH] ₂ B ₁₀ H ₁₀ are mixed with 67 ml of a 2M KOH hydroxide solution, the resulting mixture is heated to 60 ° C, the liberated tributylamine is extracted twice with toluene ( 70 ml each). The resulting aqueous solution of potassium decahydro-closo-decaborate (K ₂ B ₁₀ H ₁₀ ) is evaporated to dryness, then further dried in an oven to constant weight. The yield of K ₂ B ₁₀ H ₁₀ is 12.6 g (98% based on the starting [(C ₄ H ₉ ) ₃ NH] ₂ B ₁₀ H ₁₀ ).

Claims (1)

A method for producing the decahydro-closo-decaborate anion B ₁₀ H ₁₀ ^2- from a boron compound, characterized in that a solution of sodium undecaborate NaB ₁₁ H ₁₄ in diglyme is taken as a boron compound, tributylamine is added, the resulting solution is boiled at 160 ° C. for 1 h until the yellow color of the solution disappears, after which the reaction mixture is cooled to room temperature, water and glacial acetic acid are added to obtain a precipitate of tributylammonium decahydro-closo-decaborate, which is then filtered, washed with water and dried ayut air.