Chemical Technology Multiple Choice Questions on “ C3 Compounds – Acrylonitrile”.
1. Which method is used for the manufacture of industrial acrylonitrile?
a) Propylene-ammonia-air oxidation process
b) Catalytic dehydrogenation of isopropanol
c) Propylene alkylation of benzene
d) Contact process
Answer: a
Clarification: A C3 refinery is introduced along with ammonia and air via sprangers into a fluidized bed catalytic reactor. Acetone is manufactured by Catalytic dehydrogenation of isopropanol. Cumene is manufactured by propylene alkylation of benzene. Contact process is to produce sulfuric acid.
2. Reaction kinetics is the major engineering problem in the manufacture of acrylonitrile.
a) True
b) False
Answer: a
Clarification: This chemical reaction is one of the few commercialized where three reactants and a solid catalytic surface are all necessary involved in producing only a single major product.
3. Which catalyst is used in the manufacture of acrylonitrile from propylene-ammonia-air oxidation process?
a) Molybdenum-bismuth
b) Molybdenum
c) Silver
d) Iron
Answer: a
Clarification: Molybdenum-bismuth is used because it has excellent attrition resistance. Also, it provides more than an adsorptive surface in furnishing oxygen by surface reaction and transfer.
4. What are the by products produced in the manufacture of acrylonitrile from Propylene-ammonia-air oxidation process?
a) Cumene and acetone
b) Cumene and acetonitrile
c) Acetonitrile and hydrogen cyanide
d) Cumene and hydrogen cyanide
Answer: c
Clarification: Hydrogen cyanide and acetonitrile are produced in the product stripper reactor which further goes into a purifying column. For one ton as basis around 0.09 and 0.08 tons of acetonitrile and hydrogen cyanide is produced respectively.
5. What are the impurities present in the acrylonitrile column in the manufacture of acrylonitrile from propylene-ammonia-air oxidation process?
a) Saturated alcohol
b) Saturated carboxylic isocyanide
c) Saturated carboxylic cyanohydrin
d) Dust particles
Answer: c
Clarification: Impurities in the final acrylonitrile column which give trouble are saturated carboxylic cyanohydrins (HO-R-CN). These dissociate to form volatile contaminants.