They scale linearly, so half of everything.Reflux is not obligatory to happen for reaction to take place, if you control the reaction properly in an appropriate flask with a beefy condenser it won’t reach reflux even, especially aith 5g.If you reaction is not starting at all however with the addition of your propene, I would maybe check : if amalagam was done correctly, the purity of my raw materials (especially the propene).And ffs use distilled.