Preparation of triisobutylaluminum

Like the synthesis of triethylaluminum, the direct synthesis of triisobutylaluminum can be carried out in two stages, releasing diisobutylaluminum hydride  

The synthesis is carried out at 5-6 MPa and the temperature not exceeding 150 °C the reaction speed is much higher than in the synthesis of triethylaluminum. The processes can be carried out in tower apparatuses and in a cascade of reactors (Fig. 86). 

A suspension of toluene solution of triisobutylaluminum and activated aluminum powder is made in apparatus 4. The ready suspension is sent by nitrogen flow into collectors 5. For a continuous dosage of the suspension, there are two collectors the suspension enters one and is continuously pumped out of the other with pump 6 through collector 8 for synthesis. 

The synthesis is carried out in a cascade of three consequtive reactors 9 of the same type. The parent substances are continuously sent through collector 8 into first reactor 9 from there, the products of the reaction flow into the second and the third reactors. The given level in the first two reactors is supported by pouring the products through the piping for the third, a pressure regulator is used with a gate located on the outlet pipe. Strict observance of the level is necessary to keep the calculated synthesis time. 

This technique gives a high yield of triisobutylaluminum the degree of aluminum conversion can reach up to 90% in case of a cascade of four reactors equal in volume. 

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