Purification of aqueous, protic ionic liquid by distillation
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Kemian tekniikan korkeakoulu |
Master's thesis
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Authors
Date
2020-08-18
Department
Major/Subject
Chemical engineering
Mcode
CHEM3027
Degree programme
Master's Programme in Chemical, Biochemical and Materials Engineering
Language
en
Pages
82 + 58
Series
Abstract
Protic ionic liquid (PIL) is an equimolar mixture of a superbase and a carboxylic acid. Acetate-based PILs have been developed to dissolve cellulose for fiber production. However, the high price of PILs currently is one of the barriers to the industrial application of PILs on a large scale. The recovery and recycling processes are essential to increasing the application of PILs. Purification is the last step of the recovery process of the fiber manufacturing process. Short path distillation is a potential purification method for thermo-sensitive materials like PILs. In this study, short path distillation experiments were conducted to study whether it is possible to distill pure PIL. The operating pressure and the evaporator jacket temperature were varied to test the separation efficiency of PIL. The recovery yield of the base was 97 wt.% at 1.3 mbar and 160°C. The maximum base yield in the distillate was 94 wt.%. The minimum base yield in the residue was 1 wt.%. By-product was lower in the distillate than in the residue. The discoloration of PIL in the distillate product indicated the removal of chromophores as impurities from the initial material. The residual water was found in the cold trap. The base was possible to trap partly in the cold trap. There is still insufficient data on the thermodynamic properties of PILs. Batch distillation experiments were implemented to study the evaporation behavior of pure acetate- based PIL. The purity of the base was 99 wt.% in the first fraction with mass fraction less than 20 wt.% of the initial material. By-product was found only in the residue.Description
Supervisor
Oinas, PekkaThesis advisor
Uusi-Kyyny, PetriKeywords
protic ionic liquid, purification, distillation, short path distillation