ETD system

Electronic theses and dissertations repository

 

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
Commissione
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-<br><br>free alkylating agents or bio-based feedstocks.<br><br>A systematic study of viscosities and refractive indices has been carried out on 1-alkyl- 3-<br><br>methylimidazolium based ionic liquids (alkyl = methyl, butyl and hexyl) combined with three<br><br>phosphorous containing anions, i.e. dimethylphosphate, methyl methylphosphonate and<br><br>methylphosphonate. Despite the structural similarity of these anions, the resulting ILs show<br><br>significantly different viscosities which increase on increasing alkyl chain length on cation. On the<br><br>contrary, no correlation between refractive index and IL structure was observed. Ab initio<br><br>theoretical calculations have been carried out to rationalized the observed behavior. These ILs have<br><br>been employed with success in essential oil extraction from different matrices (cinnamom cortex,<br><br>fennel seeds and cumin seeds) using different techniques (microwave, ultrasound). We also report a<br><br>detailed study on the application of dimethylimidazolium methylphosphite as phosphorilating agent<br><br>in carbohydrate chemistry.<br><br>Furthermore, chiral ILs and Bio-based ILs have been prepared in high yield and high purity using<br><br>commercial propylene oxide and natural chiral alcohols as building blocks. The impact of alkyl<br><br>chain length and the chiral center in cation on the physico-chemical properties of the resulting salts<br><br>has been evaluated. Circular Dichroism (CD) and X-ray Photoelectron Spectroscopy (XPS) have<br><br>been used to demonstrate the assembly and layering of these ionic liquids. The self-assembly at the<br><br>interface IL/vacuum, investigated for some couples of enantiopure and racemic CILs, show that the<br><br>presence of a chiral centre on the cation side chain and the enantiomeric purity of the related<br><br>imidazolium based CILs can affect the orientation and layering of the liquid components in the<br><br>outmost regions of the interface.<br><br>Furthermore, we have studied the influence of the obtained bio based ionic liquids as solvents<br><br>and/or directing morphology agents in the synthesis of some metal oxides. The influence of the<br><br>employed ILs over the morphology and crystal structure of the nanoarchitectures was investigated<br><br>by TEM, STEM-EDX measurements.
File