Catalytic hydrogenations hexamethylene diamine

Figure 5.28. In situ wet-ETEM of real-time catalytic hydrogenation of nitrile liquids over novel Co-Ru/Ti02 nanocatalysts, (a) Fresh catalyst with Co-Ru clusters (arrowed at C). The support is marked, e.g., at u. (b) Catalyst immersed in adiponitrile liquid and H2 gas in flowing conditions growth of hexamethylene diamine (HMD) layers (at the catalyst surface S in profile, arrowed) at 81 °C, confirmed by composition analysis and mass spectrometry, (c) ED pattern of HMD in (b) in liquid environments. Further growth is observed at 100 °C. The studies show that wet-ETEM can be used to design a catalytic process (after Gai 2002). (d) Scaled up reactivity data for novel Co-Ru/Ti02 nanocatalysts confirming wet-ETEM studies of high hydrogenation activity of the nanocatalyst (2). Plots 1 and 3 are the data for Raney-Ni complexes and Ru/alumina catalysts, respectively.

The synthesis of l-aza-l-cyeloheptene and the study of its reactivity allows us to propose this compound as an important intermediate for the generation of secondary amines in the course of the catalytic hydrogenation of adiponitrile to hexamethylene diamine. 

Hexamethylene diamine (mp=42°C bpl 013 = 204oC) is obtained by the catalytic hydrogenation of adiponitrile or through 1,6-hexanediol as an intermediate. 

The commercial diamines used for nylon manufacture are usually best made by hydrogenation of the corresponding dinitriles. Hexamethylene-diamine is made by hydrogenation of the adiponitrile. Adiponitrile is now commercially produced by several methods. In the oldest method, ammonium adipate was catalytically dehydrated to the dinitrile. In a method developed since World War II, butadiene is treated with chlorine to produce mixture of dichlorobutenes. Reaction with hydrogen cyanide in the prewnce of cuprous halides yields l,4-dicyanobutene-2 exclusively. Hy-dn enation produces adiponitrile. 

In nylon 6,6 the peptide bonds are formed from the condensation of adipic acid with hexamethylene diamine. The latter could be made from adiponitrile (see Section 5.6) by catalytic hydrogenation. 

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