Pine tree painkillers? Upcycling paper industry waste for fossil-free paracetamol and ibuprofen

12 Jul 2023 --- Two of the world’s most common painkillers can be made from a compound found in pine trees, a waste product from the paper industry. Scientists from the University of Bath’s Department of Chemistry and Institute for Sustainability, UK, have discovered how to create paracetamol and ibuprofen precursors from biorenewable β-pinene, a component of turpentine.

The component is a waste by-product from the paper industry, with an annual production of over 350,000 metric tons. Everyday painkillers are produced at approximately 100,000 metric ton scales annually. Many common pharmaceuticals are manufactured using chemical precursors derived from crude oil. 

“By adopting a biorefinery approach, the paper industry could generate a broad array of products from turpentine (a low-value waste product), including drugs such as paracetamol and ibuprofen, biofuels or polymers,” Dr. Josh Tibbetts, research associate in the University’s Department of Chemistry, tells Packaging Insights. 

“This will increase the sustainability of the process as these biorenewable products could replace the oil-derived products currently on the market. In addition, it will allow the paper industry to generate added value from a waste product that is often burned for energy recovery.”

Many drugs like paracetamol and ibuprofen are made using crude oil products, reports the University of Bath.Minimizing oil and geopolitical dependencies
The research goal is to avoid extracting more oil from the ground with a “bio-refinery” model alternative. The turpentine compound is the precursor of drugs – including beta-blockers and the asthma inhaler drug salbutamol – and others widely used for making perfumes and cleaning products.

“Our turpentine-based biorefinery model uses waste chemical by-products from the paper industry to produce a spectrum of valuable, sustainable chemicals that can be used in a wide range of applications from perfumes to paracetamol,” says Tibbetts. 

Instead of putting chemicals in a large reactor to create separate batches of product, the method uses continuous flow reactors, meaning production can be uninterrupted and easier to scale up. The scientists aim to replace the chemical industry’s need for crude oil products with their “biorefinery” approach.

“It is estimated that between 250,000 to 350,000 metric tons of crude sulfate turpentine are produced annually, a significant proportion of which is beta-pinene. If a large amount of this was diverted to making painkillers and other bio-based products as part of a biorefinery, there could be a huge saving in terms of waste,” adds Tibbetts. 

“Using oil to make pharmaceuticals is unsustainable – not only is it contributing to rising CO2 emissions, but the price dramatically fluctuates as we are greatly dependent on the geopolitical stability of countries with large oil reserves, and it is only going to get more expensive.”

The cost of sustainabilityResearchers are looking to make everyday drugs and cleaning products more environmentally sustainable.  
However, the process of using β-pinene found in pine trees in its current form is more expensive than using oil-based feedstocks. The researchers believe that consumers may be prepared to pay a higher price for more sustainable pharmaceuticals that are plant-derived. 

“Wherever possible, we have used scalable processes and sustainable solvents and reagents in the chemical reactions used to convert beta-pinene to painkillers, including using flow chemistry for several steps. These should allow an easy transition from our current lab scale to an industrially relevant process,” asserts Tibbetts. 

The research, funded by the Engineering and Physical Sciences Research Council, is published in ChemSusChem.

“This work is part of a larger research program to utilize the terpenes in crude sulfate turpentine. We have published a series of other papers including the direct use of crude sulfate turpentine from a paper mill to make various bio-based chemical products including terephthalic acid (a monomer used to make PET plastic bottles),” Tibbetts concludes. 

By Sabine Waldeck