Process for preparing trialkylgallium compounds

摘要

The invention relates to a process for preparing trialkylgallium compounds of the general formula R3Ga. The process is based on the reaction of gallium trichloride (GaCh), optionally in a mixture with partially alkylated products, with an alkylaluminium compound of the type RaAICIb (where R═C1-C5-alkyl, a=1, 2 or 3, b=0, 1 or 2 and a+b=3) in the presence of at least two alkali metal halides (e.g. NaCI and KCI) as auxiliary base. Preference is given to using alkylaluminium sesquichloride (R3AI2CI3) or trialkylaluminium (R3AI). The reaction mixture is heated to a temperature in the range from 120° C. to 250° C. and the trialkylgallium compound formed is separated off via a separator which is operated at a temperature which is more than 30° C. below the boiling point of the most volatile partially alkylated product. Complete alkylation is achieved here and partially alkylated products are recirculated to the reaction mixture. In a further step, the reaction mixture can be heated to a maximum of 350° C. and the remaining fully alkylated and partially alkylated products can be separated off. The process provides a high yield of trialkylgallium compound and displays high gallium utilization; the products are used, e.g., as precursors for MOCVD processes.

主权项

1. Process for preparing trialkylgallium compounds of the general formula
R3Ga where R is a C1-C5-alkyl group, which comprises the steps: a) reaction of gallium trichloride (GaCl3) with an alkylaluminium compound of the type RaAlClb (where R is a C1-C5-alkyl group, a=1, 2 or 3, b=0, 1 or 2 and the sum a+b=3) in the presence of at least two alkali metal halides as auxiliary base; b) heating of the reaction mixture to a temperature in the range from 120 to 250° C. with simultaneous separation of the trialkylgallium compound (R3Ga) formed from the reaction mixture via a separator, where the separator is operated at a temperature which is more than 30° C. below the boiling point of the most volatile partially alkylated product of the type RcGaCld (where R is a C1-C5-alkyl group, c, d=1 or 2 and c+d=3) formed in the reaction mixture.