organic synthesis Flashcards

Question

reactions of acid anyhydrides

Answer 1

react in similar way to acyl chlorides ``` -react with: phenols water amines ammonia ```

Answer 2

HYDROLYSIS acid hydrolysis - H+/H2O - reflux alkaline hydrolysis (saponification) - NaOH/H2O - reflux - irreversable forms a salt and alcohol

Answer 3

Hydrolysis H2O/ HCl

Answer 4

electrophilic addition HNO3/H2SO4 nitronium ion, NO2+ electrophile HNO3 + H2SO4 ——> NO2+ + HSO4- +H20 FOR SINGLE SUBSTITUTION 50 °C FOR TWO SUBS - 1,3-dinitrobenzene 70 °C excess ammonia

Answer 5

NEED HALOGEN CARRIER - AlCl₃ , FeBr₃ halogen Br₂ + FeBr₃ —-> FeBr₄- + Br+ FeBr₃ benzene + Br₂ ——> bromobenzene + Hbr

Answer 6

HALOGEN CARRIER/ETHANOYL CHLORIDE ALCl₃/CH₃COCl phenylethanone + HCl

Answer 7

Buchner flask Buchner funnel pressure tubing filter paper access to filter or vacuum pump. 1. Connect one end of the pressure tubing to the vacuum outlet or to the filter pump whilst attaching the other end of the rubber tubing to the Buchner flask. 2.Fit the Buchner funnel to the Buchner flask ensuring that there is a good tight fit. This is usually obtained using a Buchner ring or a rubber bung 3.Switch on the vacuum pump, or the tap, to which your filter pump is attached. 4.Check for good suction by placing your hand across the top of the funnel. 5.Place a piece of filter paper inside the Buchner funnel and wet this with the same solvent used in preparing your solid. You should see the paper being sucked down against the holes in the funnel. 6.To filter your sample, slowly pour the reaction mixture from a beaker into the centre of the filter paper. 7.Rinse out the beaker with the solvent so that all of the solid crystals collect in the Buchner funnel. 8.Rinse the crystals in the Buchner funnel with more solvent and leave them under suction for a few minutes so that the crystals start to dry

Answer 8

Recrystallisation The solid product obtained after filtration will contain impurities which can be removed by carrying out recrystallisation. Purification by recrystallisation depends upon the desired product and the impurities having different solubilities in the chosen solvent. 1 Pour a quantity of the chosen solvent into a conical flask. If the solvent is flammable, warm the solvent over a water bath. If the solvent is water, place the conical flask on a tripod and gauze over a Bunsen and warm the solvent. 2 Tip the impure sample into a second conical flask or beaker. 3 Slowly add the solvent to the impure sample until it dissolves in the solvent. You should add the minimum volume of solvent needed to dissolve the solid. 4 Once the solid has dissolved, allow the solution to cool. Crystals of the desired product should form in the conical flask or beaker When no more crystals form, filter the crystals under reduced pressure to obtain the dry crystalline solid