Researchers at Freie Universität Berlin developed new approach for producing phosgene
Scientists at Freie Universität Berlin have developed a new type of process for the industrial production of basic chemicals. They found a new approach to phosgene, opening up completely new possibilities in the production of raw materials. Carbonyl chloride - also known as phosgene - is one of the most important basic substances in the chemical industry. For example, it is the raw material for polymers, agrochemicals, and medicines. Alone the production of polyurethanes and polycarbonates, i.e., plastics that are used as insulating materials, in CDs, or in lenses for eyeglasses, utilizes around 12 million tons of phosgene annually. This figure is estimated to rise to 18.6 million tons per year by 2030. The new process was developed by Sebastian Hasenstab-Riedel from the Institute of Chemistry and Biochemistry at Freie Universität along with scientists from Technische Universität Berlin and the Covestro company. The findings were published in the latest issue of the journal Science Advances.
Due to its high toxicity, carbonyl chloride is only produced on a large scale by a few specialized companies. In the process, carbon monoxide and chlorine are reacted at very high temperatures and high pressures with the aid of a catalyst. This is very energy intensive and requires a comprehensive safety concept.
The scientists led by Sebastian Hasenstab-Riedel were able to show that chloride ions (in the same form as they occur in table salt) in combination with special cations are very efficient catalysts for the synthesis of carbonyl chloride. As Professor Hasenstab-Riedel explains, "Chlorine and chloride ions initially form polychlorides, which in turn react with carbon monoxide to form carbonyl chloride at room temperature and normal pressure. This new process could prove to be far more efficient on a large scale than the one previously used. In addition, the polychlorides can be used as efficient, new types of chlorine storage systems that are liquid at room temperature. This could lead to a more sustainable production of chlorine in the future."