In the automatic organic synthesizer, a certain amount of thiophene and concentrated hydrobromic acid were added, the cooling system was started, and dry hydrogen bromide gas was introduced under constant stirring. When the material liquid was reduced to a certain temperature, a certain amount of formaldehyde gas was introduced (formaldehyde gas and hydrogen bromide gas were measured by weighing method). After the end of the reaction with 3 times the volume of anhydrous ether extraction 3 times, the combined extract washed with distilled water, and then dried with anhydrous sodium sulfate. After recovering the ether, the fraction at 75 /2.27 kPa was collected by distillation under reduced pressure, and a colorless oily liquid was obtained, which was analyzed by gas-mass spectrometry (GMS) to verify that the final product was 2-bromomethylthiophene.
