If you need to avoid the potential carcinogenicity, use a substituted benzaldehyde. If appropriate, the use of benzaldehyde can serve as an example of how to handle a carcinogenic substance in the lab. The hydroxide ion exchange resins are listed as eye irritants, but are much less hazardous than the concentrated NaOH solutions used in solution methods. If you convert the chloride form of the resin, aqueous NaOH will be required. It is recommended that the conversion be done by lab assistants or the faculty in charge.
Ethanol is a toxic, flammable liquid.
The used ion exchange resins can be recycled and should not be considered as waste. This will regenerate any ion exchange sites that may have been exchanged. The most probable cause of the exchange is the formation of the benzoate anion resulting from aldehyde oxidation. Some reactants seem to discolor the resins but that should not affect their behavior as catalysts. After a sufficient amount of catalyst is recovered it should be filtered on a sintered glass funnel, washed to neutrality, and used again.