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Tesi etd-12222016-185224


Thesis type
Tesi di dottorato di ricerca
Author
MARGARI, PIERO
URN
etd-12222016-185224
Title
From bio-based to halide-free, greener ionic liquids: synthesis and application.
Settore scientifico disciplinare
CHIM/06
Corso di studi
SCIENZA DEL FARMACO E DELLE SOSTANZE BIOATTIVE
Supervisors
tutor Prof.ssa Chiappe, Cinzia
commissario Prof. Martinelli, Adriano
Parole chiave
  • green chemistry
  • Ionic Liquids
Data inizio appello
05/01/2017;
Consultabilità
Parziale
Data di rilascio
05/01/2020
Riassunto analitico
During this PhD thesis we focused on the possibility to obtain greener ionic liquids using halide-

free alkylating agents or bio-based feedstocks.

A systematic study of viscosities and refractive indices has been carried out on 1-alkyl- 3-

methylimidazolium based ionic liquids (alkyl = methyl, butyl and hexyl) combined with three

phosphorous containing anions, i.e. dimethylphosphate, methyl methylphosphonate and

methylphosphonate. Despite the structural similarity of these anions, the resulting ILs show

significantly different viscosities which increase on increasing alkyl chain length on cation. On the

contrary, no correlation between refractive index and IL structure was observed. Ab initio

theoretical calculations have been carried out to rationalized the observed behavior. These ILs have

been employed with success in essential oil extraction from different matrices (cinnamom cortex,

fennel seeds and cumin seeds) using different techniques (microwave, ultrasound). We also report a

detailed study on the application of dimethylimidazolium methylphosphite as phosphorilating agent

in carbohydrate chemistry.

Furthermore, chiral ILs and Bio-based ILs have been prepared in high yield and high purity using

commercial propylene oxide and natural chiral alcohols as building blocks. The impact of alkyl

chain length and the chiral center in cation on the physico-chemical properties of the resulting salts

has been evaluated. Circular Dichroism (CD) and X-ray Photoelectron Spectroscopy (XPS) have

been used to demonstrate the assembly and layering of these ionic liquids. The self-assembly at the

interface IL/vacuum, investigated for some couples of enantiopure and racemic CILs, show that the

presence of a chiral centre on the cation side chain and the enantiomeric purity of the related

imidazolium based CILs can affect the orientation and layering of the liquid components in the

outmost regions of the interface.

Furthermore, we have studied the influence of the obtained bio based ionic liquids as solvents

and/or directing morphology agents in the synthesis of some metal oxides. The influence of the

employed ILs over the morphology and crystal structure of the nanoarchitectures was investigated

by TEM, STEM-EDX measurements.
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