Elimination, direction hydrogen cyanide

Grigg et a/.472,473 reported the first examples of the elimination of hydrogen cyanide and nitriles in retrocycloaddition reactions. The oxazoles 4 (R = H or Me) with DMAD in cold ether led directly to the furan 6 and the appropriate nitrile the expected intermediate 5 could not be isolated. The less reactive oxazole 7 was converted by DMAD into the furan 8 (69%) and benzonitrile only in boiling toluene about 10%... 

Another acrylonitrile plant supplied by-product hydrogen cyanide to various other units. An inventory of 350,000 pounds of hydrogen cyanide was eliminated by having the other units draw directly from the acrylonitrile plant. This required considerable work to resolve many issues related to acrylonitrile purity and unit scheduling. 

Sulfide, cyanide, and ammonia interfere with the determination by reacting directly with the measuring membrane of the electrode. After acidification with sulfuric acid the hydrogen cyanide and hydrogen sulfide can be carefully purged out (imder hood), eliminating their interfering effect. 

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