This paper presents an extensive study on the feasibility of ionic liquids (IL) for the extractive distillation of propene-propane mixtures. A new experimental method for express screening of non-volatile entrainers was elaborated. A series of ILs and their mixtures were screened at ambient temperature and low pressures. The screening results show that every tested IL turns a low boiler propene into a high boiler and the alkene-to-alkane separation factor can be as low as 0.28. The solubility and separation efficiency can be tuned by adjusting the chemical structures of the ions forming the IL. It was found that shortening of the alkyl substituents of the imidazolium ions leads to a decrease in capacity and to an increase in the separation factor. Interestingly, ILs containing nitrile functionalities in either the cation or the anion showed, in our experiments, enhanced separation ability combined with still good capacities. From our thermodynamic measurements, [EMIM] [[B(CN) 4 ] was proved to be the most promising candidate. Binary mixtures of ILs were also tested and resulted in separation factors and capacities between the values for the individual ILs. For the most promising candidates, also autoclave measurements at elevated temperatures and pressures were carried out. These experiments indicate that the separation ability decreases with growing temperature and loading. In general, our study definitely proves the high potential of ILs to act as entrainers in the extractive distillation of propenepropane mixtures or for the separation of any other low-boiling alkene-alkane mixture.
A novel method for the combinatorial finding of multi component reactions involving replacements of oligomerisation participants is introduced. Using this method the new three-component reaction between isoquinoline, gem-diactivated olefins and isocyanides leading to substituted 2,3-dihydro-10H-pyrrolo[2,1a]isoquinoline-1-ones is described.
The comparative reactivity of heterocyclic diazo compounds and the corresponding diazo nium salts in C azo coupling reactions was studied using imidazole, pyrazole, and triazole derivatives as examples. The reactivities of pyrazole and imidazole derived diazonium salts are much lower than those of thiadiazole and 1,2,4 triazole derived diazonium salts but higher than those of pyrrole and indole diazo compounds.
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