Liquid phase reaction with integrated separation in continuous chromatographic and membrane reactors
The project generated 3 results in the field of esterifications and chromatography: -A monolithic column for reaction with integrated separation and for chromatography. -Esterification process in Simulated Moving Bed Reactors (SMBR) with commercial exchange resins. -Modified cation exchange resins as acid catalyst. In the field of oxidations, a hollow fiber membrane reactor was successfully operated in solvent-free conditions, but the expected run length and conversions could not be reached. All tried catalysts and reactions showed problems due to inactivation of the catalyst by the products formed. The project has however yielded a wealth of insight in the phenomena involved, not previously available in literature. The partners are actively pursuing the exploitation of some of the results, both by offering licenses and implementation in their own production. Exploitation plans POLIMI/SISAS: A fixed bed reactor in the transient pulse mode has been realized both at the laboratory and pilot scale. This constitutes the basic unit for a SMBR unit operated continuously. This operation has been investigated by simulation models validated with the fixed bed units. The advantage of this technology is to couple reaction with a low temperature separation. This involves significant energy savings; in fact considering the high energy consumption of the conventional production process, even modest performance of the novel reactor/separation unit should yield a significant reduction of energy consumption (a factor of 2 to 5 reduction if the expected performance from present knowledge can be obtained). The strongly positive economic impact from the drastically reduced energy consumption is augmented by additional benefit such as: better use of raw materials and smaller compact equipment, environmental benefits (reduction of side products formation, waste streams and the possibility to avoid strong acid and toxic salt solutions). No unusual social or employment impacts are expected that are specific to these process. The realization of 6/8 beds and their dynamic operation required by the SMBR process need the collaboration of engineering companies which were not included in the project. Potential other applications are reactions with two products which can be separated by adsorption. In particular we refer to acid-catalyzed processes which both have equilibrium reaction and quite different polarity of the reaction products. These include several reaction families: esterifications, transesterifications, etherifications, acetilations, dehydration. The technology can also be successful when reactive distillation is not viable. This is the case for thermo-sensitive products (fine chemicals, food, pharmaceutics) or when the required reaction temperature has to be lower than the distillation temperature due to selectivity or equilibrium limitations. Different processes of acid functionality of styrene-DVB resins have been widely investigated in order to obtain products with a better catalytic activity and lower by-products formation. At present it is be necessary to use lab-chromatographic reactors to check the applicability of these resins for suitable esterification reactions which show by-products and low reaction rate. Polimi has developed the know-how to design and realize an optimised resin (in term of sulfonation degree and intra-particle profile) for specific reactions. Partners are sought in the direction of chemical producers willing to change their current technology based on homogeneous sulphuric acid or partners invested in the marketing of tailor mode catalytic resins. Potential application of these resins is the change of the current technology based on the homogeneous catalysis (with sulfuric acid or other soluble acids). It is convenient to get tailor mode resins in the case where the desired reaction exhibits selectivity problems. Another feature of these resins is the possibility of being easily regenerated after water adsorption. Exploitation plans TUCL: The Institute for chemical process engineering of the TUCL-group will contribute with the know-how of the preparation and operation of the monolithic columns. Introducing the described technology on the market offers the opportunity of a new product with advantages not reached by commercially available products of the state of art so far. The exploitation potential of the monolithic column can be concluded as follows: -Application in high pressure/performance liquid chromatography. -Application in the analytical and chemical industry. -Low pressure drop, high throughput, short analysing times. -Short diffusion path length because of small polymer particles and enhanced mass transfer. -Integration of reaction and separation possible. -So far no potential barriers are known. Basic information of the new product was made accessible to a potential manufacturer who is the manufacturer of the raw material (carrier material). Interest was produced, but no decisions were made so far. Further partners for the commercial production and marketing are actively looked for. Exploitation plans VUB / DUPONT: Unfortunately, as the system developed does not have the required performance, no direct exploitation is possible. We will continue the work on analysing this solution and look out for more favourable systems, even out of the oxidation area. There might be applications for the type of membrane developed in other fields. The results will be written up in papers and published as was already done with intermediate results. This might give contacts for further work.