RU2482064C1 - Method of producing niobium or tantalum pentafluoride - Google Patents

Abstract

FIELD: chemistry.

SUBSTANCE: invention relates to material science and metallurgy and specifically to methods of producing niobium or tantalum pentafluoride. The method involves reaction of niobium or tantalum metal with a fluorinating agent which is copper fluoride in ratio of not more than 4 moles of copper fluoride per mole of niobium or tantalum metal, heating the reactor to 500°C and thermal or vacuum distillation of the formed niobium or tantalum pentafluorides.

EFFECT: technology of producing niobium or tantalum pentafluoride, which does not require complex implementation and use of chemically active and highly toxic substances.

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Description

The invention relates to the field of chemical technology and can be used to obtain catalytically active niobium or tantalum pentafluoride.

A known method for producing anhydrous niobium and tantalum pentafluorides by the interaction of oxides or oxyhalides of niobium and tantalum with hydrogen fluoride in an amount of at least 5 moles per mole of starting material and a dehydrating agent (phosgene, thionyl chloride or sulfuryl chloride) at a temperature of 50-200 ° C [Pat. RF №2089505].

The disadvantages of this method is the use of corrosive hydrogen fluoride and potent toxic substances (phosgene).

A known method of producing anhydrous niobium and tantalum pentafluorides by the interaction of niobium and tantalum petachloride with hydrogen fluoride [Chemistry and technology of rare and trace elements. Part III. Under. ed. K.A.Bolshakova. Textbook manual for universities. M., "Higher. School". 1976. p. 44 and 56].

The disadvantages of this method is the use of corrosive hydrogen fluoride and pre-synthesized pentachloride niobium and tantalum.

A known method of producing niobium and tantalum pentafluorides [Chemistry and technology of rare and dispersed cements. Part III. Under. ed. K.A. Bolshakova. Textbook manual for universities. M., "Higher. School". 1976 p. 44 and 56], selected as a prototype, consists in the interaction of fluorine elements with metallic niobium plantantalum at a temperature of 300 ° C.

The disadvantage of this method is the use of elemental flora, which requires special equipment to reduce the corrosion caused by fluorine, which leads to the fact that the niobium or tantalum fluorides obtained by this method are very expensive.

An object of the present invention is to provide a cheap and reliable method for producing niobium or tantalum pentafluoride from niobium metal or tantalum.

The problem is achieved in that as a fluorinating agent, copper (II) fluoride CuF _{2 is used} . The production method includes the steps of mixing the starting niobium or tantalum with copper fluoride, initiating the reaction by heating the reactor to 500 ° C and vacuum or thermal distillation of the resulting niobium idantanth pentafluorides. The process proceeds according to the reactions:

The amount of copper fluoride used for the reaction with metallic niobium or tantalum should be no more than 4 mol of copper fluoride per 1 mol of metal according to equations (1; 2) for the formation of niobium pentafluoride or tantalum. Using more copper fluoride can lead to the formation of copper fluorobiobates and fluorotantalates (CuNbF ₆ , CuNbF ₇ , CuTaF ₆ , CuTaF ₇ ), resulting in a decrease in the yield of niobium or tantalum pentafluorides and an increase in the number of by-products, thereby increasing the cost of niobium or tantalum pentafluorides .

Example 1

To a cylindrical stainless steel reactor equipped with external heating, pre-mixed copper fluoride in the amount of 11.81 g (116.3 mmol) with niobium metal powder in the amount of 2.7 g (20.0 mmol) in the ratio Nb: CuF ₂ = 1: 4 is added . Then the reactor is equipped with a volumetric desublimator and a vacuum system. The system is evacuated and the reactor is heated to 500 ° C to initiate the reaction. The niobium pentafluoride released as a result of the reaction is sublimated and transferred to a volumetric desublimator, where it is condensed. The yield of niobium pentafluoride was 4.5 g, which corresponds to 83% of the theoretical (5.46 g).

Example 2

In a cylindrical stainless steel reactor equipped with external heating, pre-mixed copper fluoride in the amount of 8.0 g (87.3 mmol) with niobium metal powder in the amount of 2.7 (29.0 mmol) in the ratio Nb: CuF ₂ = 1: 3 was added. Then the reactor is equipped with a volumetric desublimator and a vacuum system. The system is evacuated and the reactor is heated to 500 ° C to initiate the reaction. The niobium petafluoride released as a result of the reaction is sublimated and transferred to a volumetric desublimator. where does its condensation take place. The yield of niobium pentafluoride was 5.0 g, which corresponds to 92% of the theoretical yield (5.46 g).

Example 3

In a cylindrical stainless steel reactor equipped with external heating, pre-mixed copper fluoride in the amount of 6.4 g (63.0 mmol) with tantalum metal powder in the amount of 3.8 g (21.0 mmol) in the ratio Ta: CuF ₂ = 1 is added : 3. Then the reactor is equipped with a volumetric desublimator and a vacuum system. The system is evacuated and the reactor is heated to 500 ° C to initiate the reaction. The tantalum pentafluoride released as a result of the reaction is sublimated and transferred to a volumetric desublimator, where it is condensed. The yield of tantalum pentafluoride was 5.2 g, which corresponds to 90% of the theoretical yield (5.8 g).

The use of this method allows to reduce the cost of production of niobium or tantalum fluoride through the use of a cheaper fluorinating agent that does not require the use of specific reagents and specialized equipment.

Claims (1)

A method of producing niobium or tantalum pentafluoride, comprising reacting metallic niobium or tantalum with a fluorinating agent, characterized in that copper fluoride is used as a fluorinating agent in a ratio of not more than 4 mol of copper fluoride per 1 mol of niobium or tantalum metal, the reactor is heated to 500 ° C and thermal or vacuum distillation of the resulting niobium or tantalum pentafluorides.