Extraction of safrole either by distillation or using sodium bisulfite is simple enough, but the fact your asking this here leads me to believe you're in over your head.
Safrole is pretty easy to extract from sassafras essential oil, IF you have a proper vacuum distillation rig. If you can't figure out how to get the safrole out of the oil, then you will have no chance of being able to make anything interesting from the safrole anyway.
Actually one can take take good cymbarum ocotea (or high quality brown camphor) at > 90% safrole and proceed with the reactions without distillations until you get the final product freebase oil....it will affect yield somewhat...
or you could get a hold of some synthetic vanilla (3-methoxy-4-hydroxybenzaldehyde), alkylate the phenolic moeity with methylsulfate, and go from there. at that point, de-methylate both groups, heat to about 55-60ÂșC in the presence of catalytic amounts of acid, and presto..you'll have 3,4-methylenedioxybenzaldehyde which you can work with.