博文
(2022-12-23 08:47:00)
Chloroformformsaverypoisonouscompoundcalledphosgene(COCl2)whenstoredforalongtimebyreactingwithoxygeninpresenceofsunlight.
CHCl3+1/2O2→COCl2+HCl
Inordertoconsumethatphosgenegasandmakechloroformsafe,itismixedwithethanol.
OCCl2+2HOC2H5→O=C(OC2H5)2+2HCl
Asaresult,ifyourcompoundcontainsalcoholaensitivegroup,suchasacidchlorid,donotuseusechlorformassolvent.
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(2022-12-17 21:16:27)
Eschenmoser断裂反应（埃申莫瑟断裂），又称Eschenmoser-Tanabe断裂反应，是对甲苯磺酰肼使α,β-环氧酮断裂生成含炔基和酮基化合物的反应。也译为碎片化反应、碎裂反应。反应以瑞士化学家埃尔伯特·埃申莫瑟（AlbertEschenmoser）的名字命名。原料α,β-环氧酮可通过α,β-不饱和羰基化合物与过氧化氢在碱性条件下反应得到。首先α,β-环氧酮1与芳基磺酰[阅读全文]
(2022-12-17 21:00:21)
Eschweiler(埃施韦勒)–Clarke反应TheEschweiler-Clarkereactionisanorganicreactionusedtoconvertaprimaryorsecondaryaminetoatertiaryamineusingformaldehydeandformicacid.Thisisessentiallyanaminemethylationprocesswhichbeginswiththereactionoftheaminestartingmaterialwiththeprotonatedformaldehydetoprovideanintermediateiminiumion.Theiminiumionthenreactswiththeformicacidtogiveamethylatedammoniumionandrele...[阅读全文]
(2022-12-15 19:59:52)
TheStobbecondensationisamodificationspecificforthediethylesterofsuccinicacidrequiringlessstrongbases.Anexampleisitsreactionwithbenzophenone:Areactionmechanismthatexplainstheformationofbothanestergroupandacarboxylicacidgroupiscenteredonalactoneintermediate(5):[阅读全文]
(2022-12-14 18:48:39)
TheNozaki–Hiyama–Kishireactionisanickel/chromiumcouplingreactionforminganalcoholfromthereactionofanaldehydewithanallylorvinylhalide.Intheiroriginal1977publication,TamejiroHiyamaandHitoshiNozakireportedonachromium(II)saltsolutionpreparedbyreductionofchromicchloridebylithiumaluminiumhydridetowhichwasaddedbenzaldehydeandallylchloride:ComparedtoGrignardreactions,thisreactionisveryselective...[阅读全文]
(2022-12-11 14:18:30)
TheStaudingersynthesis,alsocalledtheStaudingerketene-iminecycloaddition,isachemicalsynthesisinwhichanimine1reactswithaketene2throughanon-photochemical2+2cycloadditiontoproduceaβ-lactam3.Thereactioncarriesparticularimportanceinthesynthesisofβ-lactamantibiotics.TheStaudingersynthesisshouldnotbeconfusedwiththeStaudingerreaction,aphosphineorphosphitereactionusedtoreduceazidestoamines.Thefirs...[阅读全文]
(2022-11-20 17:44:23)
Removingpollutantsfromtheairinyourhomemeansyouandyourfamilycanbreathecleaner.Italsomeansyoucanbreatheeasierknowingthatyourheatingandcoolingsystemisn'tbeingoverworkedandraisingyourutilitybills.That'sbecausedirtcancausefurnaceorairconditionerfailureandanACorfurnacefilter'smainjobistostopdirtanddustfromenteringyourequipment. Unfortunately,filtershaveashortlifespanbecausetheyfillupquick...[阅读全文]
(2022-11-14 18:09:33)
氢是构成有机化合物的重要元素，核磁共振氢谱通过相关氢的化学位移、耦合裂分以及积分等为有机化合物的结构解析提供了大量有价值的信息。烷氢、烯氢、炔氢、芳香氢以及醛基氢等常规氢在氢谱里的表现特征性很强归属较容易。相对这类氢原子，活泼氢的解析就要复杂得多。所谓活泼氢是指有一定的酸性，容易离去或容易发生交换的氢，一般在其周围有强吸电子基团。[阅读全文]
(2022-11-13 18:48:18)
Ifyourfurnaceisgivingyouheatingissues,thegasvalvemaybetheculprit. Thegasvalvemanifoldinsidethefurnaceopensandclosestoallowyourfurnacetoburngastocreateheat. Althoughmosttimesthereareotherthingsthatyoushouldcheckbeforeyoutroubleshootthegasvalve. Firstthingsfirst-checkthatthegassupplytoyourfurnaceisopen. Anotherthingtocheckistheswitchonthegasvalvebodyinsidethefurnace. Mostgasvalves...[阅读全文]
(2022-11-02 17:12:25)
柱层析是有机合成最常用的纯化方法之一，当然也是耗时较长的纯化方法。如何用最快的速度过完一根柱子呢，今天小编给大家介绍快速柱色谱法
快速柱色谱(FlashColumnChromatography)是一种快速而且（通常是）容易的分离复杂混合物的方法。柱色谱和薄层色谱的原理一样，但它可以用于制备量物质的分离。因为我们是用压缩空气将溶剂推过柱子，故称其为快速柱色谱。这[阅读全文]
