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环丙烯
早就被制造出来了
Early synthesesThe first confirmed synthesis of cyclopropene,carried out by Dem'yanov and Doyarenko,involved the thermal decomposition of trimethylcyclopropylammonium hydroxide over platinized clay at 320-330 °C under a CO2 atmosphere.This reaction produces mainly trimethylamine and dimethylcyclopropyl amine,together with about 5% of cyclopropene.Cyclopropene can also be obtained in about 1% yield by thermolysis of the adduct of cycloheptatriene and dimethyl acetylenedicarboxylate.
[edit] Modern syntheses from allyl chloridesAllyl chloride undergoes dehydrohalogenation upon treatment with the base sodium amide at 80 °C to produce cyclopropene in 10% yield.[2]
CH2=CHCH2Cl + NaNH2 → C3H4 (cyclopropene) + NaCl + NH3
The major byproduct of the reaction is allyl amine.Adding allyl chloride to sodium bis(trimethylsilyl)amide in boiling toluene over a period of 45-60 min.produces the targeted compound in about 40% yield with an improvement in purity:[3]
CH2=CHCH2Cl + NaN(TMS)2 → C3H4 (cyclopropene) + NaCl + NH(TMS)2
1-Methylcyclopropene is synthesized similarly but at room temperature from methallylchloride using phenyllithium as the base:[4]
CH2=C(CH3)CH2Cl + LiC6H5 → CH3C3H3 (1-methylcylopropene) + LiCl + C6H6
[edit] Syntheses of derivativesTreatment of nitrocyclopropanes with sodium methoxide eliminates the nitrite,giving the respective cyclopropene derivative.The synthesis of purely aliphatic cyclopropenes was first illustrated by the copper-catalyzed additions of carbenes to alkynes.In the presence of a copper sulfate catalyst,ethyl diazoacetate reacts with acetylenes to give cyclopropenes.1,2-Dimethylcyclopropene-3-carboxylate arises via this method from 2-butyne.Copper has proved to be useful as a catalyst in a variety of cyclopropene syntheses.Copper sulfate and copper dust are among the more popular forms of copper used.