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Carbonate based ionic liquids and beyond
No full textIonic liquids appear almost like a different state of matter. Just like mercury, that I enjoyed playing with as a child after bursting thermometers. A liquid metal, and a liquid salt at room temperature are awe-inspiring, as their physical state is counterintuitive. We struggle to accept that a metal may not be hard, and that a salt may be non-crystalline, let alone liquid.
Thus, for sheer curiosity, we started synthesising ammonium and phosphonium ionic liquids. The first hurdle was to make them efficiently, colourless and pure. And this was achieved by using dimethylcarbonate (non-toxic) instead of alkyl halides as quaternarisation reagent. These syntheses were, efficient (100% atom economic), tuneable, halide-free, and produced only CO2 and methanol as by-products.1
But, ionic liquids are not just pretty. So what can we do with them?
Use them as green solvents? Sometimes yes, but often too costly, and not always an elegant or green application.
Unless we can design multiphase solvent systems with other advantages.2-3
It’s might also interesting to take advantage of the chemical properties of their ions,4 or to use them as catalysts,5-6 including for the upgrade of biogenic chemicals.7
The next question might be on how these materials work, e.g. as catalysts,8 and how can these properties be monitored.9 Or whether they can be used to make new devices, e.g. based on their luminescence.10
And why not try to make old compounds, e.g. choline, by these methods?
We will discuss this “genealogy” of applications and of examples, applied to a family of carbonate based ionic liquids.
1. Fabris, M.; Lucchini, V.; Noè, M.; Perosa, A.; Selva, M., Chem. Eur. J. 2009, 15 (45), 12273-12282.
2. Tundo, P.; Perosa, A., Chem. Soc. Rev. 2007, 36 (3), 532-550.
3. Gottardo`, M.`; Selva`, M.`; Perosa`, A. work in progress
4. Noè, M.; Perosa, A.; Selva, M.; Zambelli, L., Green Chem. 2010, 12 (9), 1654-1660.
5. Fabris, M.; Noe, M.; Perosa, A.; Selva, M.; Ballini, R., J. Org. Chem. 2012, 77 (4), 1805-1811.
6. Selva, M.; Noe, M.; Perosa, A.; Gottardo, M., Org. Biomol. Chem. 2012, 10 (32), 6569-6578.
7. Stanley`, J.`; Caretto`, A.`; Perosa`, A. work in progress
8. Lucchini, V.; Noè, M.; Selva, M.; Fabris, M.; Perosa, A., Chem. Commun. 2012, 48 (42), 5178-5180.
9. Lucchini, V.; Fabris, M.; Noe, M.; Perosa, A.; Selva, M., Int. J. Chem. Kinet. 2011, 43 (3), 154-160.
10. Fiorani`, G.; Selva, M.; Perosa`, A.`; Malba, C.; work in progress
Methylphosphonium methylcarbonate, ylide precursor for halyde- and base-free Wittig reactions
No full textThe phosphonium salt triphenylmethylphosphonium methylcarbonate [PΦ,Φ,Φ,1][OCOOCH3] was obtained by methylation of triphenylphosphine (Ph3P) with dimethylcarbonate, adopting a green and sustainable procedure1.
The [PΦ,Φ,Φ,1][OCOOCH3] phosphonium salt was observed to possess significant P-CH3 proton acidity, and deuterium exchange experiments showed the formation of the analogous PhP3-CD3 phosphonium salt. Spontaneous deprotonation of the methyl group lead therefore to formation of the corresponding phosphorus ylide, Ph3P=CH2.
This Ph3P=CH2 ylide was tested for the Wittig reaction with benzaldehyde PhCHO, generating the desired PhC=CH2 olefination product. It was noteworthy that this Wittig reaction protocol did not require an alkyl halide or a strong base for the formation of the ylide, and could be conducted in air, making it a greener procedure.
The scope of the olefination reaction was extended to a number of carbonyl substrates, both aldehydes and ketones, with high conversions and selectivity. It was performed under mild conditions (34 – 80 °C), using a ratio ylide:carbonyl between 1.0 -3.0, in 2-methyl tetrahydrofuran (2-Me-THF) as solvent.
The study was also extended to other alkylphosphonium methylcarbonate ionic liquids ([P8,8,8,1][OCOOCH3] and [P4,4,4,1][OCOOCH3]). It was demonstrated that, depending on the reaction conditions, it was possible to achieve not only the transfer of a =CH2 fragment, but also the selective transfer of the bulkier alkyl group e.g. =CH(CH2)nCH3, giving access to a variety of olefins. Cis-trans selectivity was in the range 20-80
Halide- and base-free Wittig reaction: phosphonium methylcarbonate salts as ylide precursors
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G. Stuparich, Diario di prigionia 1916-1918, a cura di S. Contarini, B. Del Buono, G. Perosa, Trieste, EUT, 2023.
No full textIl volume presenta per la prima volta al pubblico l’edizione commentata del diario di prigionia redatto da Giani Stuparich durante il suo periodo di reclusione nei campi dell’Austria-Ungheria, fra il 1916 e il 1918. Si tratta di un documento di fondamentale importanza per ricostruire il percorso esistenziale e letterario dello scrittore triestino, nel quale la dichiarata «costruzione di sé» nasce dalla rielaborazione delle vicende traumatiche del conflitto e dalla ricerca di una nuova forma espressiva da cui deriveranno i progetti artistici del dopoguerra. Nel volume sono contenuti anche uno studio e un regesto della produzione letteraria durante la prigionia: abbozzi, poesie, saggi e novelle che testimoniano la sperimentazione di generi e stili avviata nel contesto anomalo del lager. Chiude l’edizione un saggio dedicato all’analisi dell’intensa attività onirica di Stuparich e in particolare alla funzione salvifica dei «sogni di guerra» fedelmente trascritti nelle pagine di diario
Transesterificazione di carbonati organici con acetali del glicerolo in condizioni di flusso continuo
No full textLe carte della prigionia: regesto e descrizione dei materiali
No full textRegesto e breve descrizione dei materiali redatti da Stuparich durante gli anni di prigionia
Non Catalytic Continuous-Flow Transesterification of Dialkyl Carbonates with Glycerol Acetals
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