[jones005]

First of all i am sorry for my bad english!

I have made a synthesize of 1,2-dibromo-4,5-dimethoxybenzene.
This was done by adding Br2 to 1,2-Dimethoxybenzene.

My question is, if it is necessary to add the bromine to the 1,2-Dimethoxybenzene to get 1,2-dibromo-4,5-dimethoxybenzene or can the order of addition be reversed? And if so which catalyst for this reaction is needed? 

[AWK]

http://www.oc-praktikum.de/nop/en/instructions/pdf/1005_en.pdf

[OCSaviour]

Do you mean that you want to obtain 1,2-dibromo-4,5-dimethoxybenzene from 1,2-Dibromobenzene?

If yes, then try introducing two ONa groups at 4th and 5th position.

[jones005]

No like what i mean is. Do i have to add the bromine to 1,2-dimehoxybenzene or can i add 1,2-dimethoxybenzene? Because as far as i know the bromine need to be added to the 1,2-dimethoxybenzene to avoid that the bromine adds to the other positions.

[OCSaviour]

"or can I add 1,2-Dimethoxybenzene?" add it to what?

[critzz]

He means exactly what he says about the order of addition  . He wonders if he can add 1,2-dimethoxybenzene to a flask containing bromine, instead of adding bromine to a solution of 1,2-dimethoxybenzene.

[jones005]

Exactly   

[kriggy]

Itmight matter, it might not. Its likely that by adding the dimethoxybenzene into excess of bromine, you get more side products than vice versa

[orgopete]

If the bromine reacted at the rate of addition of bromine to an excess of dimethoxybenzene, what would happen if dimethoxybenzene were added to an excess of bromine? I don't know, but it certainly seems possible that additional reactions might take place. I used to keep, "Stick to what you know works!" On my hood in case I wanted to try for a miracle. (I was in industry and wasted time was wasted money.)

[OCSaviour]

He means exactly what he says about the order of addition  . He wonders if he can add 1,2-dimethoxybenzene to a flask containing bromine, instead of adding bromine to a solution of 1,2-dimethoxybenzene.

i asked him that, he denied it. Well, it's good that his query has been resolved, so it doesn't matter.

[critzz]

Do you mean that you want to obtain 1,2-dibromo-4,5-dimethoxybenzene from 1,2-Dibromobenzene?

He was still right to deny your question . Because you were giving a suggestion involving a different starting material. But he only asked if the order of addition mattered of the same two components. (addition A to B or addition B to A)
 

He wonders if he can add 1,2-dimethoxybenzene to a flask containing bromine, instead of adding bromine to a solution of 1,2-dimethoxybenzene.