Hydro(deoxygenation) Reaction Network of Lignocellulosic Oxygenates

In situ hydro-deoxygenation onto nickel-doped HZSM-5 zeolite catalyst for upgrading pyrolytic oil

Global energy demand has drastically increased due to urbanization and industrialization; thus, developing alternative renewable energy sources is urgently required. In the present work, upgrading the pyrolytic oil (PO) derived from fresh palm fruit was performed by the catalytic in situ hydrodeoxygenation (in situ HDO) process. Preparation of nickel-doped HZSM-5 zeolite (SiO2/Al2O3 = 40) was achieved by incipient wetness impregnation techniques using different weight percents of nickel dopant into HZSM-5. Nickel-doped HZSM-5 zeolite (Ni-HZSM-5) was further subjected to chemical reduction for 5 h in the oxygen-free environment (10% H2 and 90% N2) at 550 °C. The structural properties showed a potential reduction of NiO-HZSM-5 to Ni-HZSM-5, enhancing the catalytic potential. The morphological characterizations showed spherical-shaped Ni agglomerated onto HZSM-5. Acidity and oxygen contents in the pyrolytic oil were achieved by catalyst-aided HDO process at 220 °C for 6 h using methanol as a hydrogen donor. The catalytically upgraded pyrolytic oil (UPO) was analyzed for density, HHV, CHNO, and TGA. The best upgrading oil was distilled following ASTM D86 to separate gasoline, kerosene, and diesel. The acidity, density, HHV, and viscosity were measured before and after the upgradation processes. The results showed the potential impact of Ni with 10% doped on HZSM-5 on HDO reaction and illustrated the lowest oxygen content in upgraded pyrolytic oil products. Considerable decrease in viscosity and density level indicated that in situ HDO not only reduced oxygen content but also cracked pyrolytic oil to small molecules. The distilled product of upgrading oil was higher than pyrolytic oil by approximately 15% in volume. The viscosity, density, and HHV were under standard specifications of kerosene and diesel, except for acidity. However, the acidity was reduced by over 60% compared with raw material.

Selective Biocatalytic Defunctionalization of Raw Materials

Biobased raw materials, such as carbohydrates, amino acids, nucleotides, or lipids contain valuable functional groups with oxygen and nitrogen atoms. An abundance of many functional groups of the same type, such as primary or secondary hydroxy groups in carbohydrates, however, limits the synthetic usefulness if similar reactivities cannot be differentiated. Therefore, selective defunctionalization of highly functionalized biobased starting materials to differentially functionalized compounds can provide a sustainable access to chiral synthons, even in case of products with fewer functional groups. Selective defunctionalization reactions, without affecting other functional groups of the same type, are of fundamental interest for biocatalytic reactions. Controlled biocatalytic defunctionalizations of biobased raw materials are attractive for obtaining valuable platform chemicals and building blocks. The biocatalytic removal of functional groups, an important feature of natural metabolic pathways, can also be utilized in a systemic strategy for sustainable metabolite synthesis.

Titania-supported molybdenum oxide combined with Au nanoparticles as hydrogen-driven deoxydehydration catalyst of diol compounds

A heterogenous catalyst for deoxydehydration (DODH) reaction was developed using less expensive Mo than Re as the active center. Combination of Mo with anatase-rich TiO2 and Au as the support...

Homogeneous Catalyzed Valorization of Furanics: A Sustainable Bridge to Fuels and Chemicals

The development of efficient biomass valorization is imperative for the future sustainable production of chemicals and fuels. Particularly, the last decade has witnessed the development of a plethora of effective and selective transformations of bio-based furanics using homogeneous organometallic catalysis under mild conditions. In this review, we describe some of the advances regarding the conversion of target furanics into value chemicals, monomers for high-performance polymers and materials, and pharmaceutical key intermediates using homogeneous catalysis. Finally, the incorporation of furanic skeletons into complex chemical architectures by multifunctionalization routes is also described.

Selective Hydrogenolysis of Erythritol over Ir-ReOx /Rutile-TiO2 Catalyst

Partial hydrogenolysis of erythritol, which can be produced at large scale by fermentation, to 1,4-butanediol (1,4-BuD) is investigated with Ir-ReO_x /SiO₂ and Ir-ReO_x /rutile-TiO₂ catalysts. In addition to the higher conversion rate over Ir-ReO_x /TiO₂ than over Ir-ReO_x /SiO₂ , which has been also reported for glycerol hydrogenolysis, Ir-ReO_x /TiO₂ showed higher selectivity to 1,4-BuD than Ir-ReO_x /SiO₂ , especially at low conversion levels, leading to high 1,4-BuD productivity of 20 mmol_1,4-BuD  g_Ir ^-1  h^-1 at 373 K (36 % conversion, 33 % selectivity). The productivity based on the noble metal amount is higher than those reported previously, although the maximum yield of 1,4-BuD (23 %) is not higher than the highest reported values. The reactions of various triols, diols and mono-ols are tested and the selectivity and the reaction rates are compared between catalysts and between substrates. The Ir-ReO_x /TiO₂ catalyst showed about twofold higher activity than Ir-ReO_x /SiO₂ in hydrogenolysis of the C-OH bond at the 2- or 3-positions in 1,2- and 1,3-diols, respectively, whereas the hydrogenolysis of C-OH at the 1-position is less promoted by the TiO₂ support. Lowering the loading amount of Ir on TiO₂ (from 4 wt % to 2 or 1 wt %) decreases the Ir-based activity and 1,4-BuD selectivity. Similarly, increasing the loading amount on SiO₂ from 4 wt % to 20 wt % increases the Ir-based activity and 1,4-BuD selectivity, although they remain lower than those for TiO₂ -supported catalyst with 4 wt % Ir. High metal loadings on the support seem to be important.