PNC or Toray Process

Preparation ofnitrosylsulfuric acid from nitrous gases obtained from combustion of ammonia and sulfuric acid  

Preparation ofnitrosyl chloride by reaction with hydrogen chloride  

In the reaction of Eq. (21.17) a gas mixture consisting of HC1 and NOC1 is fed into cyclohexane at a temperature below 20°C. The reaction (which is initiated by Hg light) results in the formation of cyclohexanone oxime with 86% selectivity (based on benzene)46. 

Rene 2L3. Tony PNC caprolactam production process. (Reproduced by permission of Wiley-YCH) 

The industrial PNC process is based on the development of efficient photoreactors. Toray designed an immersion lamp with a high radiation efficiency and capacity as well as long life. In order to remove the short-wave radiation below 365 nm (which contributes to tar formation on the lamps) either an absorbent is added to the cooling water, or the light source is surrounded by a glass filter264. 

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