博文
(2022-05-21 06:45:33)
OnFridayoneaccidenttookplaceinmyworkduetomystupidmistake.Thereactionwasaboutepoxideringopeningbyusing3-pentanolasnucleophilicreagentcatalyzedbyborontrifluoride.Whenthereactionwascompleted,IstartedtoquenchingthereactionbyaddingaqueoussaturatedsodiumbicarbonatesolutiontothereactionRBF.Becausethesodiumbicarbonatesolutionwasaddedtoofast,lotsoffoamwasgeneratedduetotheformationofcarbondioxidefromsodiumb...[阅读全文]
(2022-05-20 16:40:37)
Reactionincludingmetalreagentusuallygenerateheatandgas!Becareful!LastFridayIhadrunonereactionwhichisaboutthe1,4-Additionof1,3-DiesterstoConjugatedEnonesbyIn/TMSCl.WhenindiumwasaddedtoTHF,nothingtooksplacebutjustleadingtoonesuspension.Whendiethylbromomalonatewasadded,stillnothinghappened.However,whenTMSClwasaddedtotheabovemixture,hugeamountofheatandgaseswereproduced.Sothereactionmixturejustoverflow...[阅读全文]
(2022-05-20 16:39:38)
TodayIhadrunonereaction:nitrosationofdiphenylamine.TlCshowsthereactionworksprettywellandnostartingmaterialsexists.Becausetheproductisoneprecipitate.SoItrytogettheproductbyfiltration.BecausethereisstillproductintheRBFafterthedumping,ItrytowashthereactionRBFusingthefiltratetogetahighyield.HoweverIforgetatthistimethetemperatureofthefiltrateishigherthatthereactiontemperatureof5degree.Becauseofthis,som...[阅读全文]
(2022-05-20 16:38:24)
ThereisonereactionbetweenAandB.TheratioofA/Bintheliteratureis1:1.2,thatis,theoreticallyAisexcess.Butafterthereaction,itwasfoundthattheexcessedAisveryhardtoseparatefromtheproductC.SothereactionratiowasmodifiedtoA/B=0.9:1.Bythis,eventhoughtheyieldwaskindofless,pureproductwasobtainedmuchmoreeasily.[阅读全文]
(2022-05-20 16:36:58)
Becarefultousethecorrectamountofreactionreagent.TodayIuseRed-Altoconvertalkynetoalkene.Theconcentrationofitwas65%byweightintoluene.HoweverIuseitaspureonemistakely.Asaresult,theamountofRed-AlIaddedtomyreactionwasnotenoughandthereactiondidnotworkwell.Fortunately,thereactionisjustinsmallscale.Otherwise,thelostwillbeterriblyhuge.[阅读全文]
(2022-05-20 16:35:43)
Diamagneticanisotropyiscommonlyusedtorationalizetheunusualchemicalshiftsofprotonsinacetyleneandinaromaticandantiaromaticcompounds.[阅读全文]
(2022-05-19 16:31:31)
Becarefultousethecorrectamountofreactionreagent.TodayIuseRed-Altoconvertalkynetoalkene.Theconcentrationofitwas65%byweightintoluene.HoweverIuseitaspureonemistakely.Asaresult,theamountofRed-AlIaddedtomyreactionwasnotenoughandthereactiondidnotworkwell.Fortunately,thereactionisjustinsmallscale.Otherwise,thelostwillbeterriblyhuge.[阅读全文]
(2022-05-19 16:30:09)
Incarbohydratechemistry,ananomerisaspecialtypeofepimer.Itisoneoftwostereoisomersofacyclicsaccharidethatdiffersonlyinitsconfigurationatthehemiacetalorhemiketalcarbon,alsocalledtheanomericcarbon.[1]Putsimply,theanomericcarbonisthecarbonylcarbon,forexampleaketoneoraldehydefunctionalgroup,inacarbohydratemolecule.Anomerizationistheprocessofconversionofoneanomertotheother.Anomerizationistheanomericanalo...[阅读全文]
(2022-05-19 16:22:30)
Inchemistryepimersarestereoisomersthatdifferinconfigurationofonlyonestereogeniccenter.Allotherstereocentersinthemolecules,ifany,arethesameineach.Thusepimericmoleculescanbeeitherenantiomersordiastereomersofeachotherdependingonwhethertherearestereocentersinadditiontotheepimericone. Inchemicalnomenclature,oneoftheepimericpairsisgiventheprefixepi-forexampleinquinineandepi-quinine.Whenthepairsareena...[阅读全文]
(2022-05-19 16:16:27)
任何一个实验，做前要仔细把过程读三遍。比如有个四氢铝锂的还原实验，尽管反应温度是室温一小时回流四小时，可加料却在负78度。而我却在室温加料把负78度忽略了。尽管实验还是成功，可还是不应该啊。[阅读全文]
