In 2004, the United States Department of Energy published a landmark report titled “Top Value Added Chemicals from Biomass,” in which they highlighted a dozen molecules as the most promising framework molecules that could potentially replace commonly used petroleum-based molecular building blocks. These 12 biobased value-added chemicals would provide prospective routes for everything from biofuels to less toxic paints and adhesives, which can be seen in Figure 1. Despite the fact that these innovations took almost 13 years to garner attention and be developed on an industrial scale, these molecules now embody the promising future of the biobased economy. The following update features four biobased chemicals with recent innovations on the market: Itaconic Acid, Glucaric Acid, 3-Hydroxybutryolactone, and 5-Hydroxymethylfurfural.
Itaconic Acid
The basic chemical composition of itaconic acid is similar to the petrochemicals currently derived from maleic acid/anhydride. Maleic anhydride is the basis for many coatings and polymers and is currently produced in large volumes for this purpose. Itaconic acid’s functionality lies in two distinct carboxylic acid groups that allow the molecule to be easily broken down into monomers and rearranged into various chemical structures. However, this production and reconstruction process is often slow and comes at a high economic cost, contributing to a slow uptake from manufacturers over the past decade.
In 2004, the key barrier to commercial success for this biobased chemical was its limited polymerization potential. However, one company has devoted itself to building up the itaconic acid market for the past 20 years, creating biobased polymers for various small-scale industrial and commercial applications. A recent agreement with AkzoNobel expands Itaconix’s economic resources and will likely accelerate the rate at which itaconic-based polymers are commercialized.
Holding 42 current patents, Itaconix sells a multitude of products in the homecare, industrial, and personal care markets. These include: non-phosphate water conditioners for dish detergents, agriculture, and industry; a no-residue odor neutralizer; mineral dispersion polymers; low-VOC paint and coating binders; flexible formaldehyde-free encapsulation technology; and even a bio-based hair styling polymer. The variety of compositions and applications of Itaconix’s products have enormous potential once they achieve commercial-scale production and market equality with conventional petroleum products.
Glucaric Acid (also called Saccharic acid)
This organic sugar comes from inexpensively obtained glucose oxidized with nitric acid, which serves as a conversion catalyst for complex sugar polysaccharide breakdown. The resulting simple sugar monosaccharaides can then be used further in biorefineries. One high value application for glucaric acid is as an intermediate in the production of biobased adipic acid, which is used to produce various polyurethanes, non-phthalate plasticizers and biodegradable polyesters, as well as 100 percent renewable nylon-6,6 fibers. This nylon is widely used in the textile and plastics engineering industries. Glucaric acid is a key feedstock that could make the process more sustainable and is currently being developed by Rennovia Inc.
Another company investing in glucaric acid technology is Rivertop Renewables, whose commercial production facility manufactured more than nine million dry pounds of sodium glucarate in 2016. Their patented chemical oxidation process fully converts the glucose feedstock by utilizing every carbon atom and adding oxygen weight, allowing for greater acid production compared to C6 sugar feedstock input. The process also allows for reagent recovery, leading to low energy consumption throughout the manufacturing process.
3-Hydroxybutryolactone (3-HBL)
As a cyclic C4 sugar compound, 3-HBL requires multiple chemical transformations during production and, therefore, is not considered to be an economically viable option as a chemical building block. However, various high value derivatives, such as gamma-butenyl-lactone and acrylate-lactone, can result from dehydration and esterification respectively. Such derivatives have potential applications in the formation of new polymers. Considering that 3-HBL is labeled a specialty chemical with fairly high value uses, not much research has been done on commercialization or potential as a commodity chemical intermediate. However, a small startup called Kalion Inc. is challenging convention by producing 3-HBL in high volumes for pharmaceutical applications.
Kalion is providing a low cost and highly efficient production route to 3-HBL, which they intend to commercialize. The main advantage of Kalion’s process is the ability to specify the chirality of the molecule and then use 3-HBL as a pharmaceutical intermediate. The basic core structure, along with the chiral specificity of 3-HBL, may potentially benefit the emerging Oxazolidinone class of antibiotics, with higher purity rates and lower costs than traditional antibiotic production methods.
5-Hydroxymethylfurfural (5-HMF)
Although not among the “Top 12” highlighted in the DOE report, this molecule was identified in the study as a major biobased chemical building block derived from starch and cellulosic C6 sugar feedstocks. 5-HMF can be synthesized from different types of C6 carbohydrates through dehydration. According to Ava Biochem, the special characteristics of 5-HMF make it “a key chemical in biochemistry and an important ingredient in the industrial production of polymers,” including resins and additives. Avalon Industries, the current market leader in 5-HMF production technology and applications, uses a cost-efficient and scalable method of hydrothermal processing to produce 5-HMF. Avalon is currently developing 5-HMF based adhesives of various types, such as phenolic, melamine and urea resins. Avalon’s goal is to create a 100 percent biobased and sustainable non-toxic adhesive in which 5-HMF fully replaces formaldehyde in each of the resin formulations.
5-Hydroxymethylfurfural contains an aldehyde group, as well as an alcohol functional group, which allows for various structural reformations once broken down into furan-monomers and corresponding polymers, leading to more than 175 product derivations and 20 different high-performance polymers. These furan derivatives have been called the “sleeping giants” of renewable chemicals due to their enormous market potential. As a key intermediate between biomass and biochemicals, 5-HMF is primarily seen as a natural, toxin-free formaldehyde replacement, which is also often biodegradable in product form. One key application lies in oxidation with furandicarboxylic acid (FDCA) as a basis for polyethylene furanoate (PEF) manufacturing, currently in commercial-scale production at several companies, including BASF, Avantium and Eastman. PEF made from 5-HMF is a biobased substitute for polyethylene (PET), which is widely, and wastefully, used in soft drink bottles and food packaging. Further applications for 5-HMF currently being developed by Avalon include agrochemicals, pharmaceutical active ingredients, wood composites, paints, and coatings.
These advancements collectively represent the general furthering of the biobased and renewable chemicals economy over the past decade, and reinforce the promise of a biobased future. According to McKinsey & Company, estimated “worldwide production of biobased products is projected to grow from approximately $203.3 billion in 2015 to $400 billion by 2020 and $487 billion by 2024.” Sustainability initiatives, as well as non-toxic alternatives, are gaining priority in the chemical industry, and one can expect an increased number of promising developments from these molecules in the future. Biobased formulations have the potential to replace a majority of petroleum-based chemical feedstocks and derivatives, therefore making everyday products greener on the most basic molecular level.
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