SU1054292A1 - Method for preparing borohydrine x complexes of rare-earth elements - Google Patents

Abstract

A METHOD FOR OBTAINING BORHIDRID COMPLEXES OF RE, COLOR-EARTH ESCHEMENTS The general formula M (VI) ,, s about 1 v .. where M is Gd, Tb, Dy, Ho, Kg, Tm, Lu, solv is a solvating solvent molecule, by interaction of a rare earth element halide alkali metal borohydride in op. ganic-g solvent with after-. dividing the desired product, characterized in that, in order to intensify the process and obtain volatile complexes, 1,2-dimethoxyethane is used as a solvent, and the initial reagents are taken in a molar ratio of 1:

Description

ABOUT

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o The invention relates to the chemistry of coordination compounds, in particular to methods for producing borohydride complexes of rare earth elements, and can be used in the separation of rare earth elements by the method of fractional sublimation, the preparation of catalysts and other compositions containing rare earth elements. A known method of obtaining the volatile borohydride complexes of rare-earth elements of the general formula Ln {BH4} in X THF (Ln-YD Ho, Er X 1.2-1.85) by reacting lithium borohydride with rare-earth chloride in tetrahydrofuran (THF) at a ratio of reagents 1: 2.2, followed by thermolysis of the Reaction Products at 390-450 K and a pressure of 0.5-200 Pa. As a result of thermolysis, the formation and sublimation of oily compounds LnCvn /}) X THF occurs. The yield of products is Low - 6.1 - 12.6%. carrying out thermolysis in the presence of an excess of boron hydride lithium increases the yield to 13.2-25%, however, there is a danger of explosion of the reaction mixture {1. The disadvantages of this method are the low yield of the target product, the use of expensive lithium borohydride and the explosion hazard of the process. The closest to the proposed technical essence and the achievable effect is a method of obtaining borohydride complexes of rare earth elements of the general formula M (BH4) 5 where M is Gd, Tb, .Dy, But, Er, Tm, Lu, solv is the solvent of the solvating solvent , taken by the action of a rare earth halide with alkali-borohydride. metal (sodium borohydride) organic solvent (tetragon furane followed by isolation of the target product by crystallization 2. The disadvantages of this method are the duration of the process (20-40 hours) and the non-volatility of the boron hydride complexes. The purpose of the invention is to intensify the process and get volatile sets. Delivered The goal is to achieve that, according to the method for producing boron hydride complexes of rare-earth elements, 1,2-dimethoxyethane is used as a solvent, and the initial reagents are taken with molar with a ratio of 1: (-4, 5-5.5). The method is carried out as follows. Halides of rare-earth elements are treated with sodium borohydride in 1,2-dimethoxyethane at a ratio of reagents of 1: (4.5-5.5) for 6-10 hours at room temperature with subsequent filtration, distilling off the solvent and thermolysis of the reaction products at 370–460 K and a pressure of less than 20 Pa with distillation of volatile borohydride and (d1C). DME from the reaction mixture. With a smaller amount of reducing agent, chlorine-containing compounds, which leads to a decrease in the yield of the target product. Some excess sodium borohydride (up to 1: 4.5-5.5) is necessary to remove traces of water present in the solvent or REE halide. Using more sodium borohydride than the amount specified in this invention is impractical because it leads to unnecessary consumption of expensive - reagent. Example. A mixture of 0.5 g (0.0018 mol) of lutetium trichloride, 0.35 g {O, 009 mol) of sodium borohydride (the ratio of reagents IABH 1: 5.0) and 50 ml of 1,2-dimethoxyethane (DME) is placed in one-neck round-bottom flask with a capacity of 100 ml and stirred under argon at room temperature for 10 h on a magnetic stirrer. The reaction mixture is filtered, the solvent is distilled off. The residue is placed in a sublimation unit and heated for 6 hours at 420–430 K and a pressure of 20 Pa. On the cooled part of the device, a crystalline product is observed. The output of bb (BH4) udma 0.35 g (63.6% of theoretical). PRI m e p2. - A mixture of 0.5 g (0.0018 ml) of thulium trichloride, 0.30 g (0.008 mol) of borohydride nat {y1 ratio of reagents TmCI |:: NaBH4. 1: 4.44 and 50 ivui, CME :) was placed in a 100 ml single-neck round-bottomed flask and stirred under argon at room temperature for 10 h on a magnetic stirrer. The reaction mixture is filtered, the solvent is distilled off, the residue is placed in a distillation tank. The target product is obtained by thermolysis of the reaction products at 370 K and a pressure of 0.1 Pa for 16 h, which yields 0.32 g of Tm (CC () DME (yield 58% of theory)). EXAMPLE 3. A mixture of 0.5 g (0.0019 mol) of gadolinium trichloride, 0.39 g (0.01 mol) of sodium borohydride (the ratio of reagents CdCl iNaBH4 is 1: 5.2 b) and 50 W. (DME is placed in a single-neck round bottom flask with a capacity of 100 ml and stirred under aiproHOM on a magnetic stirrer at room temperature for 10 h. The solution is filtered, the solvent is distilled off, the residue is placed in a reagent. The target product is Cd (BH4) DME

get vacuum sublimation at 46OK and UPA for 8 hours, at the same time 0.27 g {49% of the theoretical) The table shows the characteristics (volatile borohydride REE complexes and the results of chemical analysis,

- -t. .-. .

Boron hydrides of rare earth elements of the general formula Ln (BHi | () DME are crystalline substances with a density of 1,017,700 kg / m. Their color is determined by the nature of the corresponding Ln (lll) ions (table). These compounds decompose when heated to 460 K in an inert atmosphere, resistant to the action of dry air, carbonyl compounds, acids. They are pacTBopHNOd in dimethoxyethane, diglyme, tetrahydrofuran. The volatility of compounds increases with increasing atomic number of REE.

Claims (1)

METHOD FOR PRODUCING RARE-EARTH BORHYDRIDE COMPLEXES ELEMENTS of the general formula M (ID). Solv. where M is Gd, Tb, Dy, Ho, Er, Tm, Lu, solv is the molecule of the solvating solvent, by the interaction of the rare-earth element halide with alkali metal borohydride in op-. a chemical ·· solvent with after- ', giving the isolation of the target product, characterized in that, in order to intensify the process and obtain volatile complexes, 1,2-dimethoxyethane is used as a solvent, and the starting reagents are taken with a molar ratio of 1: (4, 5-5.5).