How is DEET (N,N-Diethyl-Meta-Toluamide) made on an industrial scale? Where can I find any information about the process besides this two patents: "Production of N,N-di(ethyl)-meta-toluamide from meta-toluic acid by liquid phase catalytic reaction with diethylamine" and "Process for the manufacture of N,N-diethyl-m-toluamide by aqueous caustic procedure"?