英文版实验报告

preparation of aspirinpurpose of experimentunderstand principles and methods of preparation of aspirinlaboratory suppliesacetic anhydride salicylic acid strong phosphoric acid cold water ice water distilled water graduated cylinder dryer distillation flasks alcohol lamp tripod asbestos nets thermometer rubber plugs condenser tube rubber hose horn tube erlenmeyer flask glue applicator beaker filter paper buchner funnel smoke filter vacuum pump filter glass rods pallet scalesexperimental principle and stepsstep one :take 20ml acetic anhydride in the dry distillation of the distillationflask.takethesteamoutof 138c abovethefractionsof6mlandtherestof the collection.as figure :phenomena:136 c began to slip out of the liquid, to 138c will be able to collect the required fraction.精品资料of aceticstep two :take 4 grams of salicylic acid in the erlenmeyer flask placed in adry, 6ml new distilled acetic anhydride, and then add 10 drops of concentrated phosphoricacid drops, control heating at 75c water bath for 20 minutes.after this heat, pour the hotwater 5ml, full shock, then poured into the 60ml cold water, in the ice water to cool for 15minutes and see.phenomena:water-bathheatingfinishes,powderreactionof salicylicacidout,onlyto seetheclarificationof liquids.coolin icewater,youcanseethesolutionbecomes a white cloudy, with significant crystallization.chemical equation:discussion.:new distilled acetic anhydride, as long the acetic anhydride may contain acetic acid, will affect the response. the distillation is not using oil-bath heating,discussion:concentratedphosphoricacidas a catalyst.water-bathheating afterthehotwater5mlisdesignedtoremoveexcessaceticanhydride.becausethematerial is 0.06 mol of acetic anhydride, salicylic acid is 0.03 mol of substance, it is clear that acetic anhydride is excessive, so the water drop.becomes cloudy and a large numberof crystallization, because aspirin builds.stepthree:these turbid pour liquid as it cools in place in a buchner funnel filter paper, cloth under the funnel to pick afilter.filter received a decompression filter,opendecompressionfilterswitch,thepumpingfilterandobserve.50mldistilledwater wash each time, then pumping filter, glass rods, gently stirring constantly.after you finishpumping filter, remember to pull the rubber hose, and then turn off the switch.phenomena:when the switchis open,fluidflow from the pumpfilter, with large numbers of crystallization on the filter paper in the funnel.after adding distilled waterwash, white cloudy smoke filtered and white crystal precipitation.discussion:finalanalysisofthepurecrystalaspirin,aspirinisan anti-inflammatory.aspirinsmokefiltersasdryaspossibleandavoidaffecting experimental results.stepfour:aspirincrystalsafterthefilterusingfilterpaperabsorb,onthe balance on the tray, called a mass of 4.2 grams.aspirin yieldin theory, aspirin, salicylic acid should be equal to the amount of material generated by the amount of substance, but the actual yield will be less than the theoretical yield.las