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ByGraduateSchoolofPharmaceuticalSciences,FacultyofPharmaceuticalSciences,TheUniversityofTokyo [閱讀全文]
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磁子表麵通常塗有耐用的化學惰性聚四氟乙烯,其對絕大數反應並沒有影響。但當磁子持續使用數月甚至數年後,表麵微小的劃痕裏可就藏了不少難以清潔的痕量活性物質,特別是鈀,金,鉑,鈷,銅或鐵等金屬納米顆粒或微粒,這些活性微粒對一些反應具有催化效果。 研究人員對60個使用過的磁子進行觀察分類,這些磁子大部分都有損耗:有顏色變化的,有劃痕的,有凹[閱讀全文]
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說起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較高的沸點,是有機合成中常用的有機溶劑之一,有萬能溶劑之稱。通常DMF在空氣中和加熱至沸點的溫度下都很穩定,但在反應體係中卻可能不那麽穩定了。 事實上,DMF在堿性和酸性條件下都可以分解產生二甲胺,這可以看成是一個酰胺的水解反應。純DMF是沒有氣味的,有時會在反應體係中聞到魚腥味,[閱讀全文]
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(2022-05-21 07:23:54)

當酸水解然後用陰離子交換樹脂中和。最終產品通過燒結漏鬥過濾蒸除溶劑拿到。結果發現產品中有不溶於水的固體顆粒。固體顆粒應該來自於樹脂。所以過濾時用膜過濾應該比較好。 [閱讀全文]
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(2022-05-21 07:14:34)
Palladiumoncarbon(Pd/C)frequentlyigniteswhenitfirstcomesincontactwithmethanol(andtoalesserextent,anyflammableorganicsolvent)andassuchrepresentsasignificantsafetyrisk.TheseproceduresarerecommendedwheneverPd/Cisusedinconjunctionwithhydrogengas. Hydrogenationusingaballoon: 1)Evacuatethereactionvessel(thisshouldhaveatleasttwoopenings)andbackfillwithaninertgas(nitrogenorargo...[閱讀全文]
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Hazards:Hydrogenationreactionsposeasignificantfirehazardduetotheuseofflammablereagentsandsolvents.Suchreagentsincludepalladiumoncarbon(Pd/C),whichishighlyflammableandcanignitesolventsandhydrogen.Itisespeciallydangerousafterhavingbeenusedforthehydrogenation.Thepresenceofhydrogengasincreasestheriskofexplosion.閱讀全文]
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Donotpouranychemicalsintothesink.[閱讀全文]
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(2022-05-21 07:10:15)
ThebehaviourofaminsonTLCsometimeisweird.Evenonepurecompound,anaminecanshowmorethanonespotwhenaneutraleluentsystemisemployed.Inthissituation,abasiceluentsystembyaddingbasesuchammoniaortriethylaminewillredresstheproblem.[閱讀全文]
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(2022-05-21 06:49:43)
nonereaction,mCPBAhasbeenusedforconvertingonealkenetooneepoxide.Afterthereaction,theexcessmeta-Chloroperoxybenzoicacidshouldnotbepouredintotheorganicwastebarrel.[閱讀全文]
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(2022-05-21 06:48:46)
Formonitoronereaction,TLCshouldbethefirstconsideration.DonotrelayonNMRformonitoringonereaction.[閱讀全文]
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