Molecules and Markets

This blog will focus on the chemical process that NileRed took which turned plastic gloves into grape soda, and the possible option of using this method to not only reduce our waste products but also solve the world hunger issues.

One of the biggest issues faced currently with regards to sustainability is the plastic waste which often lands in landfills, incineration, or the ocean. However, chemically speaking these molecules are far from useless. Most plastics such as polyethylene are composed entirely of hydrocarbons (only hydrogen and carbon), arranged in long polymer chains, not entirely different from crude oil. Meaning that under the right conditions, plastic can theoretically be broken down and processed into entirely different organic compounds. Economically, this may not be the most efficient way, however, it is something that could be worth exploring.

This concept caught my eye from a well-known chemistry experiment by NileRed, which showed that plastic gloves could be chemically converted into a compound responsible for the characteristic flavor of grape soda.In the experiment, NileRed took plastic gloves made of polyethylene (PE) , a hydrocarbon polymer – a long chain of carbon and hydrogen atoms – that broke it down and converted it into other organic molecules.

The first step was to break the plastic down by pyrolysis (thermal decomposition). When polyethylene is heated to temperatures between 400–700°C, the carbon–carbon bonds along the polymer backbone undergo homolytic cleavage, producing highly reactive free radicals. These free radicals produced by the initial supply of high energy sources such as UV or in this case heat, are highly reactive and therefore initiate the whole process of initiation, propagation, and termination. In essence, the plastic is chemically “cracked” into a mixture that resembles petrochemical feedstock, similar to products obtained from oil refineries. Some of the smaller hydrocarbons undergo secondary reactions: cyclisation (formation of chemical rings) and aromatization (planar) , forming aromatic ringed compounds such as benzene (C6H6) and toluene (C6H5CH). These aromatic molecules are extremely important in organic synthesis because they provide stable frameworks that can be chemically modified through substitution reactions. These aromatic molecules serve as starting points to synthesizing more complex molecules such as methyl anthranilate (C8​H9​NO2​), simply put; making it taste and smell like grape flavour.

Methyl anthranilate (C8​H9​NO2​), structurally consists of a benzene ring, an amine group and an ester functional group. The industrial process usually begins with anthranilic acids which are converted into the ester through a reaction with methanol. However, in this case, the carbon atoms required for constructing this molecule originate indirectly from the hydrocarbons produced during plastic pyrolysis. Through several intermediate reactions, the carbon skeleton derived from plastic is reorganized into the aromatic structure needed for the final compound.

While the chemistry is entirely possible, industrial viability on a large scale solely depends on the economics efficiency rather than the chemical possibilities. As such, other factors must be taken into account in order to weigh the opportunity costs of scientific reach and economic viability. 

Firstly, the energy costs required during pyrolysis requires temperatures of up to 700°C, meaning large energy inputs are needed to break the polymer chains. On an industrial scale, the energy costs of keeping the most basic step operational could very well outweigh the benefits of this process. The energy input needed and the fossil fuels burnt could definitely be larger than the costs of leaving the plastic as it is. Existing industrial pyrolysis plants already exist which convert plastics into fuels, but even these processes struggle to compete economically with conventional petroleum refining. With the goal of producing a relatively flavor compound like methyl anthranilate, the energy cost alone can exceed the value of the final product. More importantly, any compound intended for human consumption requires extremely high levels of purification. The purification and separation costs of the mixture of shorter hydrocarbons require extensive distillation, chromatography, and filtration, dramatically increasing production costs. 

Experiments like NileRed’s highlight an interesting economic paradox. Plastic waste contains valuable carbon atoms that can theoretically be transformed into useful chemicals, yet the cost of recovering that value often exceeds the value of the products produced. 

The real question of converting plastic waste into food for human consumption already has such complications. The focus of NileRed’s experiment shouldn’t be on the refinery to scale industrially, but rather to focus on the principle of using our plastic waste as hydrocarbon material rather than garbage. This growing field of chemical recycling has been one of the forefronts of solutions to the global plastic waste crisis. This matters because the world’s plastics problem is already enormous: OECD estimates global plastics production rose from 234 million tonnes in 2000 to 460 million tonnes in 2019, while plastic waste reached 353 million tonnes in 2019, with only 9% ultimately recycled after losses in the system. Under current policies, OECD projects plastic waste will nearly triple by 2060, with plastic leakage to the environment projected to double to 44 million tonnes per year.

This scale explains the focus on chemical recycling instead of mechanical recycling which generally melts and remoulds plastic and often suffers from downcycling, chemical recycling aims to break polymers back down into smaller molecules such as oils, monomers, gases, or aromatic building blocks which can re-enter the chemical economy. Reviews of plastic pyrolysis note that it can convert mixed plastic waste into liquid products, gases, char, and wax, and under suitable conditions fast pyrolysis can generate liquid yields in the 60–80% range, with some systems reporting yields up to 85%. In other words, the chemistry needed to recover usable hydrocarbons from plastic is not speculative; it is already technically established.

However, difficulty arises in the “glove to grape soda” idea as the human factor is added in. Not excluding that, the mixture still has to be separated, purified, and then routed through multiple steps of fine organic synthesis to produce a target molecule such as methyl anthranilate. But the safety of consumption and the societal shift that has to occur before people actually start “eating” plastic waste is too long of an investment for any profit driven business. Every extra stage of sorting waste, cleaning feedstock, running high-temperature reactors, distilling products, removing contaminants, then carrying out selective aromatic chemistry, adds capital cost, energy demand, labour, and quality-control burden. This experiment is chemically elegant, and demonstrates the abilities of man to manipulate the world around us, but commercially it resembles taking a low-value, contaminated input and forcing it through an extremely high-specification production chain.

More realistically, the industrial use of plastic pyrolysis focuses on fuels, crackers feedstock, and bulk petrochemicals. Recent reviews describe pyrolysis as promising for producing fuels and high-value-added chemical building blocks from waste plastics, and major industry analyses argue that advanced recycling could become strategically important if scale, feedstock quality, and downstream demand improve. McKinsey has argued that high-quality recycled content in packaging could reach 20–25 million tonnes per annum by 2030, suggesting that there is a real economic prize in recovering chemical value from waste plastics.

Summatively, NileRed’s experiment pushes the boundaries of chemistry and should be seen as a proof of concept for molecular reallocation. However, the most viable commercial future for that idea is unlikely to be edible products. It is far more likely to be in advanced recycling, where plastic waste is converted into fuels, feedstocks, and industrial chemicals that help reduce dependence on virgin fossil inputs. So the business verdict is not that plastic-to-grape-soda is viable. It is that the underlying chemistry is viable, while the specific food application is not commercially attractive under current technological and regulatory conditions. 

However, NileRed’s experiment could serve as a benchmark for future generations of chemical engineers with better technology and more elegant methods of refinery.