Gas-Phase Synthesis of Hydrocyanic Acid through Oxidation of N2

This project aims at revisiting the synthesis of hydrocyanic acid on an industrial scale to address two main challenges:

1. Sustainability/CO2-footprint: The current synthetic pathway starts with activating nitrogen from air via the Haber-Bosch-process and converting it in a series of chemical conversion steps to hydrocyanic acid. In synthesizing ammonia, much H2 is required, which is the reagent that accounts for the greatest carbon-footprint in chemical industry.

However, this hydrogen is not required in the final product, but it is converted to water in the subsequent steps. We therefore propose to create a novel, more sustainable process option for the synthesis of hydrocyanic acid that likely involves activation of nitrogen from the air through oxidation rather than with hydrogen. As this will be a heterogeneously catalyzed gas-phase process, continuous processing is the only reasonable mode of operation - and a gas-phase flow-chemistry process will be required to carry out R&D on this topic.

2. Distributed manufacturing: HCN is one of the most hazardous and toxic compenents that is handled in the chemical industry at large scale. Therefore, in big "Verbund" sites hydrocyanic acid is produced in one plant and directly transported to the next plant via pipelines, where it is consumed.

However, transportation on roads or rivers to other sites is undesired and almost impossible. Therefore, it is simply not available at smaller sites without a designated world-scale hydrocyanic acid plant, limiting the range of synthetic options at the smaller site and the flexibility of planning production within a company. It would be attractive to come up with a flow chemical process that can be operated at smaller sites produces just the required (small) amount.

A continuous (flow chemistry) process would be of advantage from a safety perspective (in-situ generation) and because of the specific investment in setting up the plant (in Euros per ton and year).

In its conception phase, this project will be holistically assess various processing alternatives based on sustainability and techno-economical aspects. It will require chemical engineering skills to operate gas-phase processes in a safe way. We expect a large fraction of the experimental work to deal with heterogeneous catalysis as this determines yield and selectivity of the process.