精选优质文档-倾情为你奉上Preparation of n-bromobutane一、Purpose1、Study the principle and method of preparing n-butyl bromide from n-butyl alcohol by treatment with sodium bromide and concentrated sulfuric acid2、Learn the technique of reflux with a gas trap apparatus and washing.二、Principlen-Butyl bromide can be easily prepared by allowing n-butyl alcohto react with sodium bromide and concentrated sulfuric acid.Main reactions ：NaBr + H2SO4 HBr + NaHSO4Secondary reactions：；三、Materialsn-butyl alcohol：4mLSodium bromide：5gConcentrated sulfuric acid：2.5mL/6mLAnhydrous calcium chloride:0.5g10% aqueous sodium hydroxide:5mL四、Primary reagent And Product physical constantsNameRelative molecularmassCharacterRelativedensityMeltingpointBoilingpointRefractiveindexn-bromobutane137.03colorless andtransparentliquid1.299-122.4101.61.4399n-butyl alcohol74.12colorless andtransparentliquid0.8098-89.2117.71.3993五、Apparatus 六、Procedure（1）50mLboiling flask+50mLwater+6mLconcentrated sulfuric acidAdd 4mLn-butyl alcohol+5gSodium bromide bromide Cool downReflux for 30min （2）Assembling equipmentDistill off n-bromobutane(3) Stop and simple distill5mLwater(4) 2.5mL Concentrated sulfuric acidSolutionwashingDistillate5mLwater（crude product）5mL10% aqueous sodium hydroxide5mLwaterDistill（99-103 ）Dry（CaCl2）(5) Dry（CaCl2）Refractive indexWeight and yield七、Experimental records(1) Sulfuric acid soluble in water gives off a lot of heat(2) The solution of the distillation flask become yellow and the sodium bromide dissolve(3) Solution is divided into two layers and liquid of the distillation become clear(4) Liquid layer, upper as the water phase, the lower is positive bromobutane and liquid for the milky haze(5) Liquid at 99 and stable distillation, after rising to 103 , 103 after fractions and the former part of the dont mix.八、Data recordingOutput:1.3g theoretical yield:5.8g productivity:21.7%Character: colorless and transparent liquid Refractive index:1.4372九、Experiment Discussion1、Turbidity is because it contains a variety of organic phase to organic impurities2、Plus the bottle stopper of calcium chloride anhydrous dry battery in order to prevent the water vapor in the air into the conical flask, at the same time prevent product turbidity专心-专注-专业