New Way to Make Dyes From Plant-Based Chemicals

Red dye created from plant-based chemicals
Red crystals created from plant-based molecules.

A new method for making vibrant dyes from plant-derived chemicals could help solve the clothing industry’s toxic waste problem.

“The dye and pigment manufacturing industry is one of the most polluting in the world,” said Mark Mascal, professor of chemistry in the UC Davis College of Letters and Science. That’s because the commercial dyes and pigments that color everything from clothes to currency are made from petrochemicals, and the process also results in a lot of waste, including heavy metals. 

Mascal and students at UC Davis have discovered a more sustainable way to create vibrant yellow, orange and red synthetic dyes. Adapted from earlier work by Mascal’s lab, the researchers first turned plant cellulose into 5-(chloromethyl)furfural (CMF), an organic platform molecule. Then, they combined CMF with barium carbonate and hot water, forming a yellow oil. When cooled, the oil solidified into a mass of deep yellow, needle-like crystals that can dye natural and synthetic clothing fibers. 

Fabric colored with synthetic dye
Fabric colored with a plant-based dye developed at UC Davis.

Although Mascal’s research specialty is sustainable chemistry, this is the first time his group has explored creating bio-based dyes. The experiment was inspired by research done more than 100 years ago, Mascal said. While investigating possible applications for CMF, which can be used to make everything from biofuels to pharmaceuticals, Mascal’s team noticed a 1911 report of yellow crystals formed from a similar molecule, 5-(bromomethyl)furfural. Tweaking the original approach resulted in the production of yellow, orange and red compounds from CMF.

Mascal’s team hasn’t explored whether the manufacturing CMF-based dye can be scaled up for industrial applications; however, the CMF molecule is already in commercial use. “In theory, this could lead to totally sustainable wearables,” Mascal said.  

The study was published Sept. 26 in the journal Angewandte Chemie, International Edition.

Becky Oskin, content strategist in the College of Letters and Science

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