Higher chemical yields at reduced production times
Microwaves operating with a frequency of 2.45GHz can drastically reduce chemical reactions time from hours to just minutes. This means more controlled reactions can be produced and can facilitate eco-friendly green chemistry. However, up until now, only a laboratory system could be used for the production of just a few cubic centimetres of chemicals. 'A multipurpose industrial chemical reactor using tuneable frequency microwaves' (Microchem) is a project aiming to develop a prototype chemical reactor that used microwave chemistry for continuous production of bulk chemicals at commercial production rates. The EU-funded project's objectives also included using solvent-free chemistry to avoid waste disposal problems and achieving a 10-fold step change in efficient use of resources. Researchers made progress by combining, for the first time, both microwave spinning disc reactor (MSDR) and microwave continuous flow reactor (MCFR) technologies and microwave sources in order to optimise the reaction temperature. A tuneable frequency allows the microwave process to be optimised at all stages with a view to generating maximum product yield and reducing the time spent on chemical extraction procedures. Project partners successfully designed, constructed and tested chemical microwave reactors operating at between 2 GHz and 26 GHz with various microwave powers, and completed theoretical and electromagnetic modelling for the multipurpose microwave chemical reactors. These efforts allowed for investigating the microwave thermal and non-thermal effects on chemical physical properties before, during and after interacting with the microwave energy. Other microwave reactors, including a true MCFR, were designed, constructed and tested, with a flow chemistry technique being used to optimise reaction, synthesis and scale-up of chemical reactions. A computer control using multiple sensors was designed and constructed for chemical reactions to be carried out in the MSDR and MCFR systems with optimised parameters. Results revealed major breakthroughs in terms of efficiency, energy saving and environmental issues. The size of the designed reactors allows for excellent heat and mass transfer to be achieved, resulting in higher reaction yields compared to traditional chemistry systems. Microchem members managed to drastically reduce production times, producing 200 ml in just a matter of minutes thanks to the microwave spinning disc and flow reactors optimised process. Such experiments have enhanced understanding of how microwave energy can be used to significantly speed up polar chemical reactions. The outcomes of the project stand to benefit the microwave and chemical sectors by consolidating employment opportunities and gaining a technology lead over international competitors.
