we synthesized 3,4-dimethoxythiophene (DMT) from 3,4-dibromothiophene. the yields of product is more than 90% (tested by TLC). But, after its synthesis, the extraction DMT from catalyst was very difficult. We tested different methods such as: separated by separatory funnel, solvent exchange (chloroform, diethyl ether, n-hexane, dichloromethane) and passing from sintered Glass Buchner Funnel. But, the Product remain inside the catalyst and we cannot completely separate it. would you please suggest suitable methods for the product separation without any reduction of efficiency from copper oxide (catalyst) and other remainder materials? the schematic diagram for the synthesis mechanism and synthesis method is below:  Thanks in advance.

To a three-necked flask equipped with an nitrogen purge, sodium methoxide (20.80 g, 28% mass fraction, 107.81 mmol), 3,4-dibromothiophene (5.00 g, 20.67 mmol), copper(ii) oxide (16.50 g, 207.42 mmol), potassium iodide (1.37 g, 8.25 mmol) and methanol (20 mL) were added. The reaction was refluxed for three days. Then, another sodium methoxide (20.80 g, 107.81 mmol) was added, and the solution was refluxed for another one day and was then cooled to room temperature and filtered through a sintered glass fritted funnel. The resulting soiled was then extracted with ether. The organic fractions were combined and dried with magnesium sulfate. After removal of the solvent, the remaining crude product was isolated by flash chromatography (silica gel,

petroleum ether) to give 3,4-dimethoxythiophene (2.62 g, 18.18 mmol) as colorless oil in 87.95% yield.