NEW CATALYST FOR ETHYLENE PURIFICATION AND OPTIMAL INDUSTRIAL PRODUCTION

Ethylene is the number one organic compound produced worldwide - around 100 million tonnes per year - and is the basis for many commonly used chemicals, such as polyethylene. Bags, toys or kitchen cling film are made of polyethylene. To obtain it, ethylene needs to be purified using a catalyst. Ethylene is the first organic compound produced worldwide - around 100 million tonnes per year - and is the basis for a multitude of commonly used chemicals, such as polyethylene. Bags, toys or kitchen cling film are made of polyethylene. To obtain it, ethylene needs to be purified using a catalyst. The selective semi-hydrogenation reaction of acetylene in ethylene streams is one of the largest volume processes in the petrochemical industry. The ethylene needs to be purified before polymerisation to avoid poisoning of the polymerisation catalyst by acetylene. Ethylene purification is mainly performed in so-called ‘front-end’ reactors, where acetylene is hydrogenated to ethylene. Although this hydrogenation reaction is thermodynamically favoured (ΔH°298 = -30 172 kJ/mol), a catalyst is needed, not only to overcome kinetic barriers, but also to control the selectivity of the process. The current industrial catalyst for the semi-hydrogenation of acetylene in ethylene streams is composed of Pd and Ag species, together with other additives (such as Na, Ca), and the resulting output stream must contain < 1 ppm acetylene and < 2% ethane to be industrially acceptable. In addition, a reaction temperature < 60 °C and a space velocity (WHSV) > 50,000 ml・g-1・h-1 are required to avoid over-hydrogenation reactions and unwanted polymerisations (green oil and coke formation, for example), which deactivate the catalyst. It is difficult to find any catalyst in the state of the art that meets the industrial requirements discussed above. The present invention consists of a new catalyst, embedded in a solid metal-organic framework (MOF), which allows much better control of the temperature range of the reaction and stops any secondary reactions, allowing the reaction to be carried out under industrial conditions in a safer and more efficient way, avoiding the safety and cost problems associated with the current industrial process.