张好古 - 博客

(2022-05-23 09:50:35)

说起N.N-二甲基甲酰胺（DMF）大家一定很熟悉，因其良好的溶解性和较高的沸点，是有机合成中常用的有机溶剂之一，有万能溶剂之称。通常DMF在空气中和加热至沸点的温度下都很稳定，但在反应体系中却可能不那么稳定了。事实上，DMF在碱性和酸性条件下都可以分解产生二甲胺，这可以看成是一个酰胺的水解反应。纯DMF是没有气味的，有时会在反应体系中闻到鱼腥味，[阅读全文]

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Syringe Filters

(2022-05-21 07:23:54)

当酸水解然后用阴离子交换树脂中和。最终产品通过烧结漏斗过滤蒸除溶剂拿到。结果发现产品中有不溶于水的固体颗粒。固体颗粒应该来自于树脂。所以过滤时用膜过滤应该比较好。 [阅读全文]

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Hydrogenation

(2022-05-21 07:14:34)

Palladiumoncarbon(Pd/C)frequentlyigniteswhenitfirstcomesincontactwithmethanol(andtoalesserextent,anyflammableorganicsolvent)andassuchrepresentsasignificantsafetyrisk.TheseproceduresarerecommendedwheneverPd/Cisusedinconjunctionwithhydrogengas. Hydrogenationusingaballoon: 1)Evacuatethereactionvessel(thisshouldhaveatleasttwoopenings)andbackfillwithaninertgas(nitrogenorargo...[阅读全文]

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SOP: How to Run an Atmospheric-Pressure Hydrogenation Reaction

(2022-05-21 07:12:37)

Hazards:Hydrogenationreactionsposeasignificantfirehazardduetotheuseofflammablereagentsandsolvents.Suchreagentsincludepalladiumoncarbon(Pd/C),whichishighlyflammableandcanignitesolventsandhydrogen.Itisespeciallydangerousafterhavingbeenusedforthehydrogenation.Thepresenceofhydrogengasincreasestheriskofexplosion.阅读全文]

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Do not pour any chemicals into the sink

(2022-05-21 07:11:12)

Donotpouranychemicalsintothesink.[阅读全文]

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TLC of amine

(2022-05-21 07:10:15)

ThebehaviourofaminsonTLCsometimeisweird.Evenonepurecompound,anaminecanshowmorethanonespotwhenaneutraleluentsystemisemployed.Inthissituation,abasiceluentsystembyaddingbasesuchammoniaortriethylaminewillredresstheproblem.[阅读全文]

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mCPBA

(2022-05-21 06:49:43)

nonereaction,mCPBAhasbeenusedforconvertingonealkenetooneepoxide.Afterthereaction,theexcessmeta-Chloroperoxybenzoicacidshouldnotbepouredintotheorganicwastebarrel.[阅读全文]

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Monitor One Reaction

(2022-05-21 06:48:46)

Formonitoronereaction,TLCshouldbethefirstconsideration.DonotrelayonNMRformonitoringonereaction.[阅读全文]

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More Haste, Less Speed

(2022-05-21 06:47:43)

Hastebringsnosuccess;hastemakeswaste;morehaste,lessspeed.[阅读全文]

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Don't Make Any Decision When You Are Angry.

(2022-05-21 06:46:16)

Don'tMakeAnyDecisionWhenYouAreAngry. [阅读全文]

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