Reactions that may produce dangerous products (by-products) (4)

3.

example 1

Application process: Add A to B in batches at 0℃

Remarks: HCI gas is generated in this reaction, which can be clearly seen after the reaction formula is expanded;

ArH+2HSO ₃ Cl=ArSO ₂ Cl+H ₂ SO ₄ +HCl↑

Calculating the amount of the reaction substrate, you can calculate how many moles of HCl gas is generated.

Example 2

Application process: omitted

Remarks: BBr ₃ and its reaction by-products are strongly corrosive.

Example 3

For a certain reaction, it is reported in the literature that the benzyl group (Bn) can be debenzyl (Bn) only when hydrogenation is pressurized and hydrochloric acid is added

Application process: need to pressurize with hydrogen and react under strong acid conditions of 2mol/L HCl

Remarks: After the reaction is de-Boc, the free amine will be toxic to palladium, which will inactivate the palladium and thus lose the debenzylation activity, so it must be carried out in a strong acid environment

Example 4

Application process: Add phosphorus tribromide to the ether solution with compound A dissolved at 0°C

Remarks: ①The heat of reaction is large, and the heat capacity of ether is small.