Scaling-up the environmentally friendly production of Perspex®
The research group of Professor Peter Edwards and Doctor Paul Newman of the School of Chemistry in collaboration with Lucite International have developed a new method to produce the essential building block of Perspex® in a way that reduces costs and environmentally harmful processes and waste.
Poly(methyl methacrylate), more commonly known as Perspex® is used widely in industry, however recent years have seen increasing supply constraints begin to limit the supply. Research led by Professor Peter Edwards and Doctor Paul Newman working with Lucite International has created the precursor of Perspex®, Methyl Methacrylate (MMA) using a new method called the ALPHA process. This process has reduced the costs associated with MMA manufacture by 40%, while also replacing an environmentally harmful process.
The history of Perspex®
Perspex® was first created in 1930’s by ICI, now known as Lucite International, since then it’s monomer methyl methacrylate has become a globally traded commodity. In the almost 70 years since the invention of Perspex® the only means of producing the monomer necessary for its manufacture required costly and dangerous amounts of hydrogen cyanide and concentrated sulphuric acid. It also resulted in the production of toxic by-products.
The existing manufacturing methods were also not readily scalable, which limited the size of manufacturing plants. A further advantage of the ALPHA process is that it removes these scale limitations, enabling large manufacturing plants allowing significantly improved economies of scale.
The ALPHA process
The ALPHA process developed by Edwards and Newman is a new and highly efficient means to create a critical catalyst needed to make MMA, however its initial method of creation was prohibitively expensive. Lucite International set the Edwards/Newman group the challenge to develop a cost-effective method to produce this essential catalytic component.
The most important step in this process was identifying the ideal feedstock for the process. The team compared ethylene and acetylene, both of which made for ideal feedstocks on paper. However, only one could be taken forward to pilot testing and eventually production. In tests acetylene was identified as the most efficient feedstock, due to lower cost and greater air stability. Most importantly the reaction mechanism used to turn it into MMA was a single step process. However, an impurity found in acetylene feedstocks, allene, irreversibly poisoned the catalysts rendering them inert. Removing allene from the acetylene feedstocks was unviable, and as such ethylene was selected despite its reaction having a slower, two-step mechanism.
High efficiency manufacture
With continued support from Leucite international the team refined the process to the point that it’s performance could not be matched by competing methodologies. The key to the process is the remarkable efficiency of the catalyst in the addition of carbon monoxide to ethylene, which is very fast. It can produce 13kg of product from 1g of palladium metal per hour of operation. It is also vastly cost efficient with regard to the amount of palladium metal consumed, with 10,000kg of product produced for 1g of metal consumed.
Lucite estimate that the cost of running the ALPHA process is 40% cheaper to operate than their previous manufacturing plants. This resulted in the construction of Alpha 1 and Alpha 2, in Saudi Arabia. These are the largest MMA plants in the world, created with an investment of US$1.1 billion, currently suppling a combined 370,000 tonnes of the worlds MMA supply, around 10% of all annual MMA production worldwide. Due to their success Lucite have broken ground on Alpha 3 on the Gulf of Mexico in the USA with a planned capacity of 350,000 tonnes annually, set to begin operations in 2025.
High demand
With the high demand for high quality Perspex® in the manufacture of mobile phones, tv screens and computer monitors, the ability to increase the supply in a less costly, and environmentally damaging way is of great benefit. Lucite stated that: “MMA derived through the ALPHA process produces the required quality as an end product, removing the significant manufacturing costs involved for this extra step.”
