Most polymers and plastics require six-carbon ring structures. Sugars (such as glucose and xylose) derived from cellulose and hemicellulose are converted into five-atom ring structures called furans, which consist of four carbons and one oxygen. In order to make the right carbon atom ring, CCEI has introduced technology for the production of aromatics from furans by combining reactor experiments and first-principles computations. The overall chemistry combines cycloaddition and dehydration chemistries. In one example, glucose derived from biomass is initially reacted to produce dimethylfuran (DMF), which is then reduced and reacted to make para-xylene with 90% yield. Para-xylene can be used for the production of terephthalic acid and eventually for polyester PET.
Sugars to Furans
CCEI introduced an iconic technology for the isomerization of aldoses to ketoses production via Sn-beta zeolite and other related heterogeneous and homogeneous Lewis acid catalysts in water and demonstrated that this technology is broadly applicable to the conversion of C6 and C5 sugars. Researchers discovered the first single-pot process that combines heterogeneous Lewis acidity with Bronsted acidity to carry out isomerization and dehydration reactions for the production of C6 and C5 furans and developed intrinsic kinetics, reaction mechanisms, and fundamental models for these processes. In addition, we introduced various novel processes (e.g., reactive adsorption) and chemistries (e.g., combination of isomerization with dehydration and etherification) toward the production of fuels and chemicals.
Bio-oil and oxygenated intermediates derived from sugars are oxygen rich. In order to be transformed to fuels and chemicals, selective oxygen removal is required. CCEI develops the hydrodeoxygenation science to improve product yields, introduce new chemicals, and reduce catalyst cost with optimal hydrogen management. We have developed the first high-yield catalytic transfer hydrogenation technology to reduce furans without external H2, a high-yield diesel-grade fuels technology from HMF using a single inexpensive catalyst without external H2, inexpensive and selective catalysts for production of propylene from C3 bio-oil oxygenates, and catalytic reforming technologies.
CCEI has a growing portfolio of novel classes of materials with tunable micro-, meso-, and/or hierarchical pores and functional groups, including:
(1) three-dimensionally ordered mesoporous (3DOm) carbons, titanias, and zirconias
(2) 3DOm-imprinted zeolites
(3) hollow mesoporous carbons
(4) hierarchically porous MFI and MEL zeolites
These materials hold exciting implications for realizing both adsorption and reaction selectivity, enhancing hydrothermal stability, and reducing transport limitations specific to complex biorefinery streams. As such, the materials themselves and the strategies for their facile synthesis represent a unique and versatile capability of the center that cuts across various research areas and holds broader implications for impacting general chemicals processing.
Major developments have taken place in first-principles-based prediction of reforming and hydrodeoxygenation catalysts for key biomass derivatives. These developments can eventually assist in catalyst and process design for bio-oil upgrade and conversion of furan-based compounds into fuels and value-added chemicals. In addition, first-principles multiscale simulations of Lewis acid catalyzed isomerization and epimerization of aldoses to ketoses and dehydration chemistry using homogeneous and heterogeneous catalysts have been performed for the first time. Solvent effects on spectroscopic signatures, molecular solvation, and reaction chemistry are being explored. First-principles semi-empirical methods are being developed for predicting thermochemistry and kinetics on catalysts and separation performance (adsorption, extraction, etc.).
CCEI’s technology is based on electrolytes that are ceramic oxygen-ion conductors, such as cubic zirconia. It uses molten antimony (Sb) as the fuel electrode. Inside the fuel cell, Sb is oxidized at the electrolyte interface to Sb2O3, producing electrical power. The Sb2O3 is in turn reduced by carbon-based fuels to regenerate the Sb, allowing the cycle to start again.
The next generation of biofuels will be produced by high-temperature (>1000 °F) pyrolysis or gasification of lignocellulosic biomass. At these temperatures, large biopolymers (such as cellulose) thermally fracture to smaller fragments, which can evaporate and be collected as bio-oil. Subsequent upgrading of bio-oil then produces gasoline, diesel and jet fuel. Thus, the future of biofuels depends on the production of high-quality, low-cost bio-oil. CCEI develops techniques for measuring and modeling intrinsic kinetics (e.g., thin film pyrolysis, co-pyrolysis, Car-Parrinello molecular dynamics) for the first time. Fundamental kinetic models can then be used for scale-up.