Heterogeneous process copper reactor

Mitsui Toatsu Chemical, Inc. disclosed a similar process usiag Raney copper (74) shortiy after the discovery at Dow, and BASF came out with a variation of the copper catalyst ia 1974 (75). Siace 1971 several hundred patents have shown modifications and improvements to this technology, both homogeneous and heterogeneous, and reviews of these processes have been pubHshed (76). Nalco Chemical Company has patented a process based essentially on Raney copper catalyst (77) ia both slurry and fixed-bed reactors and produces acrylamide monomer mainly for internal uses. Other producers ia Europe, besides Dow and American Cyanamid, iaclude AUied CoUoids and Stockhausen, who are beheved to use processes similar to the Raney copper technology of Mitsui Toatsu, and all have captive uses. Acrylamide is also produced ia large quantities ia Japan. Mitsui Toatsu and Mitsubishi are the largest producers, and both are beheved to use Raney copper catalysts ia a fixed bed reactor and to sell iato the merchant market. 

On the other hand, studying the influence of the surface material on the DMTM process in one [140] of a series of works, where a very high selectivity of methanol formation (P = 30 atm, T = 350 °C, tj- > 100 s) was observed, revealed no significant differences in the selectivity and yield of methanol in reactors with different surfaces, such as Pyrex, Teflon, stainless steel, silver, and copper. In these experiments, the selectivity of methanol formation on all surfaces reached values close to 90% or more, whereas the methanol yield was as high as 10.7%. However, the authors do not exclude the possibility of influence of the surface material on the temperature and reaction time. In particular, it was found that the maximum selectivity in reactors with metal surfaces was achieved at temperatures higher by nearly 50 °C. This is probably due to the fact that, at lower temperatures in the presence of a metal surface, the oxidation occurs mostly in the heterogeneous mode with the formation of mainly deep-oxidation products. 

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