Researchers develop biomass alternative of chemical used in production of PET bottles

The research uses the same chemical, p-xylene that is currently used to produce polyethylene terephthalate (PET) but produces it with the added benefit that it can be plant-based and renewable unlike the current method of using petroleum.

The process creates the chemical p-xylene with a current yield of 75% and utilization of most of the biomass feedstock according to project leader Paul J Dauenhauer.

The discovery could lead to the chemical being used to make PET without having any noticeable effect on the end product, say the researchers at the University of Massachusetts Amherst.

Work to achieve higher yield​

The project, started early last year, is ongoing as the researchers look to achieve a higher yield and look for a company to help take the process to test plant stage, Dauenhauer explained to FoodProductionDaily.com.

“The first benefit is it is more sustainable as the p-xylene and PET market keeps going up which leads to the second benefit, being cost  advantageous ​and the production rate of biomass and PET providing a market advantage.​

“The trends are clear. We are making the same product and the consumer or company will not be able to tell the difference in terms of quality and supply.​

“Hopefully it will keep packaging costs to a minimum or stop them growing and it is a more sustainable process.” ​

P-xylene is used to make terephthalic acid, which in turn is made into PET for products including beverage bottles and food packaging.

The new process transforms glucose into p-xylene in a three-step reaction within a high-temperature biomass reactor.

In the reaction, glucose is converted to dimethylfuran and ethylene, which undergoes a reaction at 300°C, before a dehydration step which produces p-xylene, also known as para-xylene.

Dauenhauer said: “If we got the yield up to 99% we would be very happy.​

“We are in the stage of development, as we have made the discovery in the laboratory we need to go to the pilot plant test stage next but we are still a couple of years away from that.​

“Our technology is cheaper and produces a higher yield than alternatives but price and yield are not synonymous.” ​

Catalyst design​

Dauenhauer added that they had to design a zeolite catalyst as the reaction didn’t want to happen when the two chemicals were mixed together.

“To go through the process of seeing it doesn’t work at first to the breakthrough in a year, which isn’t a lot in research terms, is very exciting,” ​he added.

The research, funded by the US Department of Energy Catalysis Center for Energy Innovation as part of the Energy Frontiers Research Center (EFRC), combined more than 20 faculty members.

Dauenhauer’s team included UMass Amherst Professor Wei Fan and doctoral students in chemical engineering C. Luke Williams and Chun-Chih Chang.

Professors Raul F. Lobo, Dionisios G. Vlachos and Stavros Caratzoulas, doctoral student Nima Nikbin, and postdoctoral fellow Phuong Do of the University of Delaware, were part of the research team.