Preparation of dibutyltindibromide by the radiation chemical technique

The production process of dibutyltindibromide is based on the interaction of butylbromide with metallic tin at 85-90 °C in the presence of activating additives (butyl alcohol or water) and under the influence of ionising y-radiation  

Raw stock tin (powder of 10-40 pm particles with 99.5% of the main substance) butylbromide ( pure ). The radiation chemical synthesis of dibutyltindibromide is very sensitive towards impurities in parent reactants therefore, they should be thoroughly purified. Thus, before being sent into the reactor, tin powder is washed from organic impurities with acetone, treated with diluted hydrochloric acid to remove oxide film, washed with distilled water and dried. 

The reactor for radiation chemical synthesis with an agitator (about 200 rotations per minute) is located in the operation chamber. Inside the reactor there is a cavity for introducing sources of y-radiation. The role of the radiation source is played by 60Co in airproof stainless steel ampules the activity of 60Co radiation is about 3000 eq Ra. The consumption degree of the energy of radiation when the sources are placed in the cavity, or the radiation coefficient of efficiency, varies from 17 to 19%. The equipment is encased in a special box made of stainless steel and plexiglass the box has intensive ventilation. 

The reactor is draft-loaded with corresponding amounts of butylbromide, tin and butyl alcohol. Then the apparatus is closed with a lid fashioned with an agitator, moved into the operation chamber and connected to all piping. After that the jacket of the reactor is filled with a heat carrier with a temperature of 90-95 °C, the contents of the apparatus are heated at agitation to 85-90 °C, the operation chamber is closed with a protective plug and sources of y-radiation are introduced into the chamber. After certain periods of time the mixture in the reactor is sampled with the help of a special sampler. 8-10 hours after the radiation has started, the reaction is completed and the sources of radiation are taken out of the chamber. The reactive mixture is loaded off and the apparatus is prepared for the next operation. 

The production of dibutyltindibromide by this technique can also be carried out in the so-called pseudocontinious mode. In this case, after the reaction has developed and the concentration of the target product in the mixture is 60-70%, the agitator is periodically stopped for a short time so that tin settles down. Then, part of the reactive mixture is sucked off and the apparatus is loaded with an additional amount of reactants. 

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