250+ TOP MCQs on Isoprene and Answers

Chemical Technology Multiple Choice Questions on “C3 Compounds – Isoprene”.

1. Which among the following methods is not used for the manufacture of isoprene?
a) Isomerization of propylene dimer
b) Isobutylene formaldehyde reaction
c) Methyl ethyl ketone formaldehyde reaction
d) Ethylene cyanohydrin pyrolysis

Answer: d
Clarification: Ethylene cyanohydrin pyrolysis is done for the manufacture of industrial acrylonitrile whereas Isomerization of propylene dimer, Isobutylene formaldehyde reaction and Methyl ethyl ketone formaldehyde reaction is done for the manufacture of isoprene.

2. Which catalyst is used in the manufacture of isoprene by isomerization of propylene dimer?
a) Triethyl aluminium
b) Trimethyl aluminium
c) Triphenyl aluminium
d) Tripropyl aluminium

Answer: d
Clarification: A compressed propylene is reacted with tripropyl aluminium catalyst along with a carrier solvent at 200atms pressure in a reactor filled with heat transfer surface to remove exothermic heat of reaction.

3. Isoprene can be polymerized with a stereospecific catalyst. True or false?
a) True
b) False

Answer: a
Clarification: Isoprene can be polymerized with a stereospecific catalyst and a range of cis-4-polybutadiene-polyisoprene elastomer bends can be manufactured.

4. What are the series of chemical reactions in manufacture of isoprene from isomerization of polypropylene dimer?
a) Dimerization-Isomerization-Pyrolysis
b) Pyrolysis-Isomerization-Dimerization
c) Dimerization-Pyrolysis-Isomerization
d) Pyrolysis-Dimerization-Isomerization

Answer: a
Clarification: Initially propylene is dimerized using tripropyl aluminium as catalyst which forms 2-methyl-1-pentene which further on isomerization forms 2-methyl-2-pentene and finally undergoes pyrolysis to form isoprene.

5. What kind of a catalyst is used in the packed bed reactor of isomerization section in the manufacture of isoprene from isomerization of polypropylene dimer?
a) Neutral type catalyst
b) Solid catalyst
c) Acid type catalyst
d) Gas type catalyst

Answer: c
Clarification: Isomerization occurs in a packed bed reactor containing an acid type catalyst. Process conditions range from 150-300 ° with liquid velocity of 15 to .5 m/s.

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