CS276405B6 - Process for producing triethylamine borane (3) - Google Patents

Abstract

Method for producing triethylamine-borane /3/ by pressure hydrogenation of a mixture of aluminum, triethylamine trifluoroborane /3/ and triethylamine in the presence of isopropylamine and sodium at a temperature of 130 to 180 C and a hydrogen pressure of 5 to 20 MPa* The reaction is carried out in molar ratios BFg : CgHyNHg : Na = 1 · 0.4 to 1 with 0.1 to 0.4. The product is used as a reducing agent in organic syntheses and as a basic raw material for the synthesis of higher boranes.

Description

(57)

Process for producing tristhylamine borane (3) by pressure hydrogenation of a mixture of aluminum, triethylamine trifluoroborane (3) and triethylamine in the presence of isopropylamine and sodium at a temperature of 130 to 180 C and a hydrogen pressure of 5 to 20 MPa.

Na = 1 · 0.4 to 1 with 0.1 to 0.4. The product is used as a reducing agent in organic syntheses and as a basic raw material for the synthesis of higher boranes.

(13) Type of document: B6 (51) Int. Cl. ⁵ :

OJ C 07 F 5/02

CS 275405 B6

The present invention relates to a process for the production of triethylamine borane (3) by pressure hydrogenation of aluminum in the presence of a boron compound.

Trialkyamine boranes (3) are used as reducing agents in organic syntheses and as a raw material base for the preparation of higher boranes (Kirk-Othmer: Encyclopedia of Chemical Technology vol. 3, p. 728, Interscience Publishers and Division of 3ohn Wiley and Sons, Inc. New York 1967. Sodium tetrahydroborate is used most frequently as a base material and reacted with the appropriate trialkylammonium chloride, and water is added to the reaction mixture in a trialkyl amine. After filtration of the resulting sodium chloride, the product is isolated by distillation (Bonham Drago RS: Inorganic Syntheses 9,8 (1967). From the ammonium cadmium or zinc borohydride complexes triethylamine borane (3) can be obtained in triethylamine by reaction with hydrogen sulfide (US Pat. 2,294,698 /.

For the synthesis of triethylamine borane (3), reduction reactions of boronic esters or boron halides can be used. Lithium aluminum hydride (US) is used as reducing agent. U.S. Pat. No. 3,257,455], sodium aluminum hydride (Baton Rouge: O.Organometal.Chem.

(5), 371 (1965)] or sodium borohydride (U.S. Pat. U.S. Pat. 3,153,671 /.

Using eilane as the reducing agent, the ee reaction is carried out at a pressure of 6 MPa (British Pat. 927 652).

The reduction takes place at elevated temperatures under hydrogen pressure even in the presence of activated magnesium or aluminum. The activation of the aluminum is carried out with triethylaluminum at 140 ° C under a hydrogen pressure of 7 MPa. The actual reduction is then carried out in a second stage at 220 ° C and 35 MPa.

On the other hand, the object of the attached drawing is a process for the production of triethylamine borane (3) by pressure hydrogenation of a mixture of aluminum and triethylamine trifluoroborane (3) in a triethylamine environment at a temperature of 130 to 180 ° C and a hydrogen pressure of 5 to 20 MPa. the presence of isopropylamine and sodium in the molar ratios of BF ₃ : C 8 H 4 NH ₃ ; Na 1: 0.4 to 1: 0.1 to 0.4.

The process according to the invention is also suitable for the preparation of triethylamine borane (3) with a boron isotope (R) B from a starting boron trifluoride with a boron isotope (* B).

An example of an embodiment of the method according to the invention is described below.

Exemplary embodiment

In a 200 ml shaking autoclave containing 3 steel mixing balls of n diameter

1.2 cm, 4 g of 98% aluminum in the form of grits having a surface of 0.180 m / g (0.145 mol) were introduced,

16.9 g of BFgNEtg (0.1 mol), 5.9 g of CgHyNHg (0.1 mol), 0.5 g of Na (0.02 mol) and 30 ml of triethylamine. The autoclave was pressurized to 20 psi at 20 ° C and then heated at 170 ° C with shaking for 18 h at which time the maximum pressure was reached. The pressure increase was 1.48 MPa (calculated to 0 ° C). Over the next 12 h heating and shaking, the pressure drop was 1.00 MPa (calculated to 0 ° C). After cooling, the contents of the autoclave were poured into a flask and after filtering off the excess aluminum, washing the filter cake twice with 5 ml of triethylamine, the combined filtrates were distilled through a 20 cm packed column and a 6.7 g fraction collected at 103 ° C. N, C: H: N = 6.03: 17.98: 1. The yield of the synthesis for the present BFgNEtg was 58.25%.

PATENT CLAIMS

Claims (1)

Process for the preparation of triethylamine borane (3) by pressure hydrogenation of a mixture of a boron compound with triethylamine in the presence of aluminum at a temperature of 130 to 180 ° C under a hydrogen pressure of 5 to 20 MPa, characterized in that hydrogenation is carried out in triethylamine with triethylamine trifluoroborane. in the presence of 1 to 1.4 moles of isopropylamine and 0.1 to 0.4 moles of sodium, calculated per 1 mol of triethylamine trifluoroborene (3).