In 1930 Alder was appointed reader for chemistry at Kiel, and promoted to lecturer in 1934. In 1936 he left Kiel to join I G Farben Industrie at Leverkusen, where he worked on synthetic rubber. In 1940, he was appointed Professor of Experimental Chemistry and Chemical Technology at the University of Cologne and Director of the Institute of Chemistry there. Throughout this time and despite the many obstacles to original research in Europe at the time, he continued a systematic program of investigations of his particular interests in the synthesis of organic compounds. In all he published more than 151 papers in this field. 