Cellulose Pyrolysis Catalyzed using [bmim][BF4] and [bmim][TFSI] Ionic Liquids Supported on Silica and ZrO2 & TiO2

DOI: 10.5176/2251-189X_SEES17.19

Authors: Michael Behrens, Hiroki Akasaka, Naoto Ohtake, and Jeffrey S. Cross

Abstract: Biomass based liquid chemicals have become attractive due to dwindling petroleum reserves. Pyrolysis is a common thermochemical process for obtaining high yields of products containing a range of useful chemicals from biomass. Catalyst reactions are being pursued to produce desired chemicals. In this research, cellulose is pyrolyzed and the vapors are catalyzed using supported ionic liquid catalysts. The ionic liquids [bmim][BF4] and [bmim][TFSI] were supported on silica and ZrO2&TiO2 materials using the incipient wetness method. The catalysts were analyzed with TG-DTA to confirm the synthesis and determine the operating temperature of the supported ionic liquid. The affects of the catalyst were determined and had a significant impact on the levoglucosan and levoglucosenone concentration in the pyrolysis products as measured by GC-MS. The silica support had an average of 1{6e6090cdd558c53a8bc18225ef4499fead9160abd3419ad4f137e902b483c465} GC-MS area for levoglucosan while ZrO2&TiO2 had an average of 10{6e6090cdd558c53a8bc18225ef4499fead9160abd3419ad4f137e902b483c465}. The [bmim][BF4] coating had an average of 0.4{6e6090cdd558c53a8bc18225ef4499fead9160abd3419ad4f137e902b483c465} GC-MS area for levoglucosenone while the [bmim][TFSI] increased the GC-MS area of levoglucosenone to an average of 1.6{6e6090cdd558c53a8bc18225ef4499fead9160abd3419ad4f137e902b483c465}. Increasing the [bmim][TFSI] coating thickness also showed to increase further the levoglucosenone concentration up to 2.5{6e6090cdd558c53a8bc18225ef4499fead9160abd3419ad4f137e902b483c465}. This paper discusses the interactions between the ionic liquid and pyrolysis vapors as well as the mechanism for the formation of levoglucosenone.

Keywords: Pyrolysis, cellulose, pyrolysis, [bmim][BF4], [bmim][TFSI], supported ionic liquid phase, levoglucosan, levoglucosenone