Hydrodeoxygenation (HDO) is a
hydrogenolysis
Hydrogenolysis is a chemical reaction whereby a carbon–carbon or carbon–heteroatom single bond is cleaved or undergoes lysis (breakdown) by hydrogen.Ralph Connor, Homer Adkins. Hydrogenolysis Of Oxygenated Organic Compounds. J. Am. Chem. Soc. ...
process for removing
oxygen
Oxygen is the chemical element with the symbol O and atomic number 8. It is a member of the chalcogen group in the periodic table, a highly reactive nonmetal, and an oxidizing agent that readily forms oxides with most elements as ...
from oxygen-containing compounds. Typical HDO catalysts commonly are sulfided
nickel
Nickel is a chemical element with symbol Ni and atomic number 28. It is a silvery-white lustrous metal with a slight golden tinge. Nickel is a hard and ductile transition metal. Pure nickel is chemically reactive but large pieces are slow ...
-
molybdenum or
cobalt
Cobalt is a chemical element with the symbol Co and atomic number 27. As with nickel, cobalt is found in the Earth's crust only in a chemically combined form, save for small deposits found in alloys of natural meteoric iron. The free element, p ...
-molybdenum on gamma
alumina. An idealized reaction is:
:
R2O + 2 H2 -> H2O + 2 RH
The first review on HDO was published in 1983. HDO is of interest in producing
biofuels, which are derived from oxygen-rich precursors like sugars or lipids. An example of a biomass refining process employing hydrodeoxygenation is the
NEXBTL process.
HDO of biomass fast pyrolysis vapors under low hydrogen pressures have recently attracted a lot of attention. Bulk molybdenum trioxide (MoO3) was used as catalyst and found to completely deoxygenate cellulose, corn stover, and lignin pyrolysis vapors and produce a stream of hydrocarbons including aromatics, alkenes, and alkanes.
[{{Cite journal, last=Shanks, first=Brent H., last2=Saraeian, first2=Alireza, last3=Nolte, first3=Michael W., date=2017-07-31, title=Hydrodeoxygenation of cellulose pyrolysis model compounds using molybdenum oxide and low pressure hydrogen, journal=Green Chemistry, language=en, volume=19, issue=15, pages=3654–3664, doi=10.1039/C7GC01477E, issn=1463-9270] From an economic viewpoint, only aromatics and alkenes should ideally be produced to enable product incorporation into the existing infrastructure.
References
Chemical processes
Petroleum technology