Typical experimental procedures can be found for each catalytic reaction. Please note that these procedures are the starting suggestions meant to be starting points. Sometimes, optimization steps need to be undertaken to optimize yields and increase selectivity. Various parameters can be changed, one at a time or simultaneously, to improve results.
Number of mol % of SiliaCat Catalysts
For each new experiment, we suggest using a molar percent of SiliaCat with respect to the substrate. This quantity has to then be optimized in order to obtain a good catalytic activity with the lowest consumption of the SiliaCat. For initial experiments we suggest to use an higher mol % of SiliaCat Catalyst in respect to the substrate and then decrease the quantity if yield and kinetics are already in line with your needs. During development applications work at SiliCycle, we always start using 1 mol % of catalyst.
SiliaCat can safely be used in a wide range of organic and aqueous solvents commonly used in laboratory and in process work, such as DMF, DMSO, THF, ACN, alcohols, ethers, chlorinated solvents, water, etc. The nature of the solvent does sometimes influence the catalytic efficiency, however. If yield is low or kinetics are too slow, changing solvent or adding a co-solvent should be considered.
At low substrate concentration, the activity of the catalyst will be directly proportional to the number of moles of substrate available. If you increase the concentration of the substrate, the activity will increase until the active sites become saturated. So the substrate concentration is a parameter that needs to be optimized to develop your catalytic conditions.
A catalyst’s purpose is to enhance the kinetics of a reaction, so we recommend running the experiments at room temperature. In the optimization step, the temperature could be adjusted, if it is needed.
In the case that the TOF is low, and increasing the temperature to increase the kinetics is not possible, we recommend increasing the contact time with the catalyst to complete the reaction. Also, in this case, increasing of the amount of catalyst is an option.