BASF adiponitrile process

The application of electrochemistry in organic synthesis had already served to bring on stream in the United States in 1965 Monsanto s first industrial adiponitrile process from acrylonitrile. This was followed in 1977 by a similar installation in Seal Sands, England, which was later bought up by BASF. 

Like in the first example of the BASF acetal process, a unique feamre of organic electrochemistry is employed. In this case the desired product is elegantly generated at the cathode in one step with only one substrate and water as proton source. The first main developments have been conducted at Mmisanto by M. M. Baizer and his colleagues [24, 25]. Therefore, this adiponitrile process is often referred to as Monsanto process. As the electrohydrodimerization appeals by its atom efficiency, the realization of this efficiency has not been easy. The electrohydrodimerization takes place at quite negative potential [26]. In addition the needed proton source delivers at the... 

Adiponitnle (hexanedinitnle, dicyanobutane, ADN), NC(CH2)4CN, is manufactured principally for use as an intermediate for hexamethylenediarnine (1,6-diaminohexane), which is a principal ingredient for nylon-6,6. However, in 1996, BASF aimounced the development of a process to make caprolactam from adiponitrile (44,45). Caprolactam is used to produce nylon-6. The implementation of this technology could increase the demand for adiponitrile dramatically. 

Uses. The principal use of adiponitrile is for hydrogenation to hexamethylene diamine leading to nylon-6,6. However, as a result of BASF s new adiponitrile-to-caprolactam process, a significant fraction of ADN produced may find its way into nylon-6 production. Adipoquanamine, which is prepared by the reaction of adiponitrile with dicyandiamide [461-58-5] (cyanoguanidine), may have uses in melamine—urea amino resins (qv) (see "Benzonitrile, Uses"). Its typical liquid nitrile properties suggest its use as an extractant for aromatic hydrocarbons. 

In terms of sustainability, the process starting from propene would be preferable, since it avoids the risks connected with the use of HCN in the butadiene route, even if produced on demand. However, the butadiene route to produce adiponitrile (ADN) is more cost-effective, owing to the need to use an electrochemical reaction for acrylonitrile dimerization. The problem of cost, however, is highly dependent on several factors, including sensitivity to natural gas prices (which influences butadiene cost), the market for acrylonitrile, and soon. The acrylonitrile route is used by Solutia, BASF and Asahi Kasei. New plants to make caprolactam, using ADN as intermediate, are under construction in Asia. 

Trickle-bed reactors are used by Du Pont (18) and by B/BF (19) A scheme of the BASF process is shown on Figure 7 (20). Adiponitrile and ammonia are mixed with recirculated liquid products before entering the trickle-bed. Hydrogen flows concurrently with the liquid. At the exit of the reactor, the gas and the liquid are separated successively in a hot and in a cold separator. Part of the cooled liquid is recirculated to limit the increase of temperature in the catalytic bed. 

Also other companies like Asahi and BASF have applied this electrohydrodimerization of acryloifitrile to adiponitrile and have searched for the optimum process [18, 25]. Over many years, the electrosynthesis of adiponitrile has been the electroorganic process with the highest... 

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