Reducing the carbon footprint of this common chemical could reduce air pollution

Researchers unveiled an alternative approach for producing epoxide chemicals that are extensively used to make various products. The electricity-based technique does not require extreme temperatures and pressures. It also does not emit the air pollutant carbon dioxide, resulting in a much-reduced carbon footprint.

The industrial manufacture of iron, steel, plastics, and similar products account for the lion’s share of the energy spent around the world. Many of these processes also give off carbon dioxide.

The Massachusetts Institute of Technology (MIT) research team looked for a way to save energy and reduce air pollution. They chose to improve the method of producing epoxides.

“What isn’t often realized is that industrial energy usage is far greater than transportation or residential usage,” explained MIT researcher Karthish Manthiram, the senior author of the paper. “This is the elephant in the room, and there has been very little technical progress in terms of being able to reduce industrial energy consumption.”

While waiting on the patent, Manthiram and her team are refining their new method for scaling up to industrial levels of usage. (Related: New study shows cities have double the carbon footprint previously thought; one from within their borders, and an equally sized one from supply chains.)

The manufacture of epoxides uses tons of energy and gives off lots of carbon dioxide

Epoxides are used in the manufacture of all kinds of products. Antifreeze, detergents, and polyesters are just some of the items that rely on these chemicals.

Unfortunately, several epoxides emit considerable amounts of carbon dioxide. Ethylene oxide, for example, accounts for the fifth most significant carbon footprint among chemical products.

The synthesis of ethylene oxide and other epoxides involves many chemical reactions. Many of these manufacturing processes consume a lot of energy, and most of that electricity comes from fossil fuel power plants.

In the production of ethylene oxide, an ethylene molecule receives an oxygen atom. The chemical reaction requires a temperature of 572 F (300 C) and air pressure 20 times stronger than atmospheric pressure at sea level.

Synthesizing ethylene oxide also produces carbon dioxide. The byproduct is released into the atmosphere as air pollution, increasing its carbon footprint.

Other epoxides are worse. Some of them require even more complex methods. They also need dangerous chemicals like inflammable peroxides and calcium hydroxide that damages the skin.

Water oxidation-based technique can produce epoxides cheaply and cleanly

The MIT researchers turned to water oxidation, a chemical reaction that uses electricity to break down water molecules into oxygen, protons, and electrons. They took the oxygen atom and attached it to an olefin, an organic compound that serves as a building block for epoxides.

Normally, olefins and water do not react with each other. However, applying an electric voltage – such as the one used in water oxidation – enables chemical reactions between the two substances.

The researchers devised a reactor that broke down water into oxygen, hydrogen ions, and electrons. They used tiny particles of manganese oxide to catalyze the oxidation process. The nanoparticle catalysts also attached the oxygen atoms to olefins, thereby producing an epoxide called cyclooctene oxide.

Meanwhile, the reactor’s cathode attracted hydrogen protons and electrons. The cathode converted these particles into hydrogen gas, a clean fuel used in fuel cell systems.

The entire process needed just one volt of electricity. A standard AA battery would provide more than enough power for the job. Using renewable energy from solar and wind sources might reduce the carbon footprint even further.

The researchers are modifying their new process to produce other epoxides. They also hoped to increase its efficiency at converting olefins into epoxides, which would make the process even cheaper and cleaner.

Sources include:

ScienceDaily.com

Pubs.ACS.org