在有機合成中,有一個“寵兒”溶劑,那就是二氯甲烷,很多試劑在二氯甲烷中都有良好的溶解性,由于沸點較低,反應(yīng)結(jié)束后后處理和旋蒸也比較方面。此外,它的性適中,也是一類很好的點板和柱層析的洗脫劑。
In organic synthesis, there is a "favorite" solvent, which is dichloromethane. Many reagents have good solubility in dichloromethane. Due to the low boiling point, the post-treatment and rotary evaporation after the reaction are also relatively good. In addition, it has moderate properties and is also a good kind of eluting agent for spot plate and column chromatography.
然而,正是由于它的討喜性,很多合成人員都選擇用它。導(dǎo)致它的一些負面影響報道的很少。所示的實驗:
However, because of its pleasing nature, many synthesizers choose to use it. There are few reports about its negative effects. Experiments shown:
10%的吡啶二氯甲烷溶液,狀態(tài)隨著靜置時間的變化,從外觀可以看出,隨著時間的不斷推移,溶液體系里面會析出很多的固體。很明顯,吡啶與二氯甲烷發(fā)生了反應(yīng)。
The state of 10% pyridine dichloromethane solution changes with the standing time. From the appearance, it can be seen that with the passage of time, a lot of solid will be precipitated from the solution system. It is obvious that pyridine reacts with dichloromethane.
提出了反應(yīng)的可能機理,由于吡啶氮雜原子具有孤對電子,使其具有親核性,與二氯甲烷進行兩次親核取代反應(yīng),得到二吡啶甲烷鹽酸鹽。因此當(dāng)你的反應(yīng)涉及到吡啶底物時,請謹慎使用二氯甲烷作為溶劑。
The possible mechanism of the reaction is proposed. Because pyridine nitrogen heteroatom has solitary pair electrons, it has nucleophilicity. It undergoes two nucleophilic substitution reactions with dichloromethane to obtain dipyridine methane hydrochloride. Therefore, when your reaction involves pyridine substrate, please use dichloromethane as solvent carefully.
如果你做的反應(yīng)或后處理涉及到疊氮化物,如疊氮化鈉時,那么這個時候如果你是用了二氯甲烷,根據(jù)上面的機理會生成什么?危險性不言而喻,相信很多公司的培訓(xùn)都有講過,疊氮化鈉是禁止與多鹵代烷烴接觸的。
If your reaction or post-treatment involves azides, such as sodium azide, what will be generated according to the above mechanism if you use dichloromethane at this time? The danger is self-evident. I believe that many companies' safety training has said that sodium azide is prohibited from contacting with polyhalogenated alkanes.
當(dāng)然除了氮原子作為親核試劑會參與反應(yīng),氧,硫,膦等親核性較強的雜原子都可能與二氯甲烷反應(yīng)。大家在使用過程中需要充分考慮二氯基烷對我們反應(yīng)和我們自己的帶來的可能的負面影響。更多相關(guān)內(nèi)容就來我們網(wǎng)站
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Of course, in addition to the nitrogen atom as a nucleophilic reagent that will participate in the reaction, oxygen, sulfur, phosphine and other heteroatoms with strong nucleophilicity may react with dichloromethane. You need to fully consider the possible negative impact of dichloroalkanes on our reaction and our own safety during use. Come to our website for more relevant content http://www.laiyanglicheng.com consulting service