Novel Compounds and Methods for Upgrading Biomass to Produce Premium Biofuels

Simple Methods for the Direct Umpolung Self-Condensation of HMF into DHMF

At a Glance

HMF (5-hydroxymethylfurfural) has been identified as an important chemical intermediate in a proposed biorefining pathway. Known to be derivable from biomass, HMF can be a feedstock chemical for conversion into biofuels and other value-added chemicals.

Biofuels such as ethanol are already in use as alternatives to fossil fuels. These man-made fuels help to offset carbon dioxide emissions and are a sustainable source of power. Unfortunately, they are generally made from materials that could be used as food; therefore, researchers are investigating means to turn inedible biomass sources, like sawdust, into biofuels. While methods to upgrade HMF into biofuel exist, they currently require the addition of other carbon-rich chemicals to create a usable fuel, which increases fuel production costs. A definite need exists for biofuels with greater energy density for use as jet fuels or kerosene, yet there are currently few viable and cost-effective methods to create such a biofuel.


While alternative fuels from biological sources are currently in use, these first-generation biofuels are derived from edible crops that divert from the global food supply resulting in higher food costs and global food shortages. It is widely recognized that the future of biofuels is in the conversion of inedible sources of biomass (e.g., sawdust, straws, grasses, forest wastes, and other plant matter – collectively referred to as lignocellulosic biomass or plant biomass). The global supply of such naturally renewable biomass is enormous and inexpensive.

It is well known within the biofuel industry that biorefining of value-added chemicals is an essential component to any successful operation. Analogous to oil refining within the petroleum industry, biorefining allows for the production of chemical feedstocks and an array of value-added products that nicely complement biofuel production.

HMF (5’-hydroxymethylfurfural) has been identified as a key and versatile biorefining building block for sustainable chemicals, materials, and liquid fuels. The HMF pathway is highly desirable as the conversion of cellulose to HMF can be achieved through chemical, biological, and hydrothermal pathways.

Nevertheless, several challenges and opportunities exist with the HMF chemical pathway. Methods suitable for the industrial scale conversion of cellulose to HMF have not been developed. Furthermore, although the easiest accessible biofuel from HMF (dimethylfuran, DMF) is twice as energy dense as ethanol, it is still only a six carbon (C6) fuel and therefore, not as energy dense as higher carbon forms of fuel, such as jet fuel or (bio)diesel. Upgrading of HMF to a higher carbon fuel without the use of additional carbon sources is a particularly difficult challenge for which no industrially acceptable solutions exist.

Accordingly, new methods are needed for upgrading HMF into useful intermediates and products.


Researchers in the Chemistry department at Colorado State University have developed a novel means by which the biofuel intermediate HMF may be upgraded into a kerosene or jet fuel intermediate (DHMF). This upgrading process enhances the energy density of the fuel by adding additional carbon atoms and is compatible with any known biomass-to-HMF technologies. This technology has the potential to be part of a one-pot biofuel production method wherein biomass is converted to HMF, then HMF to DHMF without the need for purification between steps. The resulting DHMF need only undergo further trivial processing—hydrogenation or hydrogenolysis—to become useful jet or kerosene (C12) biofuel. This technology may also allow for the upgrading of HMF to diesel (C24) biofuel.

This HMF-to-DHMF process offers many advantages that will help biofuel compete with its petroleum equivalent. The catalyst upgrades HMF to DHMF at room temperature or under industrially preferred conditions (60° to 80°C). Yields in excess of 86% have been realized under industrial settings. The conversion catalyst is nontoxic and rapidly upgrades HMF to DHMF: conversion times range from 1 to 24 hours depending on temperature.

This technology will be especially interesting to biofuel producers. It offers the potential for a one-pot jet biofuel (C12) production method, as well as the possibility of diesel (C24) biofuel production. The reaction is most efficient in industrial conditions and offers a nontoxic alternative to other HMF-upgrading methods.


  • Rapid, high yield conversion process
  • Nontoxic catalyst operates efficiently under industrially-preferred conditions
  • Compatible with known biomass-to-HMF processes
  • Potential one-pot biofuel synthesis
  • Reduces biofuel production costs and steps by eliminating additional carbon-rich chemicals


  • Jet fuel and kerosene (C12) generation
  • Chemicals for synthetic chemistry
Last Updated: June 2023
Novel Compounds and Methods for Upgrading Biomass to Produce Premium Biofuels

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Eugene Chen
Dajiang Liu

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