Acrylonitrile Process

Fig. 2. Acrylonitrile process showing integration of waste heat from reactor and off-gas incinerator. The reaction in the reactor is...

Figure 8-2. A flow diagram of the Montedison-UOP acrylonitrile process. ...

Fig. 2. Acrylonitrile process showing integration of waste heat from reactor and off-gas incinerator. The reaction in the reactor is C3H6 + NH3 + 1.5 02 — C3H3N + 3 H20 + heat in the off-gas incinerator, C3H8 + 5 02 — 3 C02 + 4 H20 + heat.

Power consumers in the acrylonitrile process are the air compressors, as well as the compressors of the refrigeration units for HCN condensation. These can be largely covered by HP steam produced in the reactor in combined heat and power cycles. 

Figure 11.9 Final flowsheet for acrylonitrile process by the ammoxidation of propene.

Fig. 10.21. Simplified diagram of the Sohio acrylonitrile process (a) fluidized-bed reactor (b) absorber column (c) extractive distillation column (d) acetonitrile stripping column (e) lights fractionation column (f) product column. (Patrick IV. Langvardt, Ullmann s Encyclopedia of Industrial Chemistry, IV. Gerhartz (Ed.), 5lh ed. Vol. A1, p.179, 1985. Copyright Wiley-VCH Verlag GmbH Co KG. Used with permission of the copyright owner and the author.)...

Six processes are presently of economic significance the Andrussow process is currently the principal HCN manufacturing process in the world, the BMA process is practiced by two companies and provides high yield and selectivity by using a complex reaction system, the Fluohmic process is of interest in locations where electricity is inexpensive, the formamide process is useful for sites with inexpensive carbon monoxide, the BP (British Petroleum) acrylonitrile process produces HCN as a byproduct, and the methanol process. 

Acrylonitrile Process. The Standard Oil Company of Ohio (now BP Amoco) commercialized in 1960 a fluidized bed process in which the catalytic oxidation of a mixture of propylene and ammonia produces acrylonitrile (ACRN). Byproducts from this reaction are HCN and acetonitrile. The yields of HCN depend on the process conditions and on the catalyst system.131 The reactions are ... 

In the case of the VPO catalyst for the butane oxidation process and the MCM catalyst for the acrylonitrile process, the preferred precursor of the peripheral hard phase is polysilicic acid (PSA). The term "polysilicic acid" is generally reserved for those "silicic acids that have been formed and partially polymerized in the pH range 1-4 and consist of ultimate silica particles generally smaller than 3-4 nm diameter" (4). Small, discrete particles of colloidal silica also migrate to the periphery of the droplet, but they do not coalesce as extensively as PSA in drying. The larger the particle size, the lower the mechanical strength of the coalesced dry product. 

I am grateful to my colleagues at the Du Pont Experimental Station listed below for their help and support to apply the novel concepts described in this report to produce viable catalysts. Brian S. Malone and Rashmi M. Contractor conducted the attrition resistance and activity/selectivity measurements of the VPO-PSA catalysts in apparatuses of their own design. William J. Linn tested catalytic performance of the MCM-PSA products in the acrylonitrile process. EPMA micrographs were obtained by Joseph W. Brennan. SEM pictures were taken by Michael L. Van Kavelaar. The late Gunther Teufer conducted the X-ray diffraction and electron diffraction analysis. 

A new current challenge is the shift from propene to propane as feedstock. Since the early 1990s it has been necessary to develop new generations of multi-component catalysts to improve the performance. However, both technical and economic conditions (the price differential between propane and propene) now exist for the commercial introduction of direct propane to acrylonitrile processes. Initial exam-... 

Schonbeck, R OSW Newest acrylonitrile process", Hydrocarbon Processing, 46 (8) 124-126 (1967). 

Caponfi. G Montecatim Edison s acrylonitrile process, AICHE 65th National Meeting Texas, (20 23 Feb. 1972k... 

Application The IN EOS acrylonitrile technology, known as the SOHIO acrylonitrile process, is used in the manufacture of over 95% of the world s acrylonitrile. INEOS Technologies licenses the acrylonitrile process technology and manufactures and markets the catalyst that is used in the acrylonitrile process. 

As noted, ABS is produced by a combination of the three monomers acrylonitrile, butadiene, and styrene. Each of the monomers impart different properties hardness, chemical and heat resistance from acrylonitrile processability, gloss and strength from styrene and toughness and impact resistance from butadiane. Morphologically, ABS is an amorphous resin. 

Propylene Ammoxidation. The possibility of producing acrylonitrile by the reaction of propylene and ammonia was first revealed in 1949 in a patent assigned to Allied Chemical (1). However, the reaction when catalyzed by a V-Mo-P-0 mixed oxide produced acrylonitrile in less than 10% yield. The commercialization of a propylene-to-acrylonitrile process only became possible with the invention of catalysts that effectively change the mechanism from that dictated by gas-phase kinetics to one in which the surface reaction provides a pathway, giving a higher yield of acrylonitrile than is possible from the uncatalyzed thermal reaction. 

Other Acrylonitrile Processes. Processes rendered obsolete by the propylene ammoxidation process (42) include the ethylene cyanohydrin process (43-45) practiced commercially by American Cyanamid and Union Carbide in the United States and by I. G. Farben in Germany. The process involves the production of ethylene cyanohydrin by the base-catalyzed addition of HCN to ethylene oxide in the liquid phase at about 60°C, and subsequent dehydration. 

The Sohio Acrylonitrile Process Ameriean Chemical Society National Historic Chemical Landmarks Washington, DC, November 17, 2007. 

The reaction network of propylene ammoxidation is not fully understood, but a kinetic model can be approximated by the network shown in Fig. 18. For decades, the Sohio acrylonitrile process has utilized turbulent fluidized beds for propylene ammoxidation... 

Sohio Acrylonitrile Process. This process, developed in the late 1950s by Standard Oil Company of Ohio, produces hydrogen cyanide and acetonitrile as by-products of acrylonitrile production. Ironically, the manufacture of acrylonitrile used to be the largest consumer of HCN until the Sohio process became the principal source of acrylonitrile in the 1960s. The by-product from the Sohio process was estimated to have supplied 20 percent of the HCN demand in 1990. The chemistry involves ... 

The Sohio lliridized bed acrylonitrile process has proved to be extremely successful and provides most of the worldwide acrylonitrile demand. During operation the catalyst temperature is controlled by circrrlatmg water through vertical tubes within Ac catalyst bed. 

---