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DIMERIZATION &
OILGOMERIZATION
Homogeneous Catalysis- Major Industrial
Processes
Processes/Products
Production, MTA
Terephthalic acid & Poly(Ethylene Terephthalate)
9
Acetic acid & acetyl chemicals
7
Aldehydes and alcohols- Hydroformylation
6
Adiponitrile- Hydrocyanation
1
Detergent-range alkenes- SHOP- Oligomerization
1
Alpha Olefins (C4- C20)- Dimerization &
4
Oligomerization
Total fine chemicals manufacture
<1
Olefins Polymerization (60% uses Ziegler-Natta)
60
Oligomerization & Dimerization – Key homogeneous processes
Dimerization & Oligomerization Processes
Dimerization of ethylene to Butene-1- Co-monomer in
LLDPE- IFP & SABIC processes
Dimerization of propylene- Methyl pentenes & HexenesGasoline additives- DIMERSOL- IFP Sumitomo & BP
processes
Dimerization of Butadiene- 1,5 Cyclo-octadieneCyclooctene- (ROP)- Vestenamer-Hulls process
Trimerization of Butadiene-Cyclododecatriene- (ROP)Vestamid-Hulls process
Butadiene+ Ethylene co-polymerization-EPDM rubberDuPont-Process
Oligomerization of ethylene to Linear Alpha Olefins- LAO
- Chevron-Phillips,(Gulf Oil)-GULFTENE, Ineos (Ethyl),
Idemitsu, Conaco, Shell (SHOP), SABIC ( -SABLIN)
Basis for the production of wide range of useful olefins & monomers
Alpha Olefins-Applications
C4 to C6
Co-monomers in polyethylene (4-12%)
C8 to C10
C10 to C12
Plasticizer alcohols
Synthetic lubricants
C12 to C16
Detergents - Linear Alkyl Benzene (LAB)
Alpha Olefin Sulphonates (LAO)
C16 to C18 Lube oils, Surfactants
C20 to C30+ Oil field Chemicals, Wax replacements
Alpha Olefins via Ziegler Process
100 C, 10MPa
300 C, 1MPa
Gulf Oil (1966) / Chevron (1983) Process
• One step process with simultaneous chain growth & elimination
• At 200 C & 25 Mpa ethylene pressure, with heptane as solvent
• 0.4 wt% AlET3 w.r.t ethylene
• Ethyl’s process is an improved version of Gulf’s
Processes for
Processes →
Products↓
- Olefins - Comparison of product quality
Wax
Cracking
Chevron
Ethyl
SHOP
-Olefins
83-89
91-97
63-98
96-98
Branched
olefins
3-12
2-8
2-29
1-3
Paraffins
1-2
1.4
0.1-0.8
0.1
Dienes
3-6
-
-
-
Mono olefins
92-95
99
>99
99.9
Shell Higher Olefins Process (SHOP)
Involves four processes
1.
Oligomerization of ethylene to C4-C20+ α- olefins 80 to 120 °C
and 70 to 140 bar (7 to 14 MPa) with a nickel phsophine
complex (C6H5)2P(CH2)2COONi- Homogeneous
2.
Isomerization of α-olefins to internal olefins- Heterogeneous
3.
Metathesis of C20+olefins with C4-C8 olefins- Heterogeneous
4.
Isomerization, hydroformylation & hydrogenation to αalcohols- Homogeneous
Shell’s SHOP Process-Stepwise conversions
Step. 1- Oligomerization
H2C=CH2 -----------→ H (CH2-CH2)n-CH=CH2 n= 1 to 19
Ni complex
Step.2- Fractionation of alpha-olefins
C10-C14 - Olefins
C4-C10 - Olefins
C16-C40 - Olefins
Step.3 – Hydroformylation of C10-C14 Olefins
C10-C14 Olefins ------------→C11-C15 alcohols
H2+CO
CH3(CH2)7-CH=CH2-------------→CH3(CH2)7-CH2- CH2 –CHO
Co(Co)6
↓ H2
CH3(CH2)7-CH2- CH2 –CH2- OH
Shell’s SHOP Process-Stepwise Conversions
Step.4 – Isomerization
Catalyst Na/K on Al2O3 or Mgo
C4-C10 - Olefins ------------→ C4-C10 Internal olefins
C16 –C40 - Olefins ------------→ C16 –C40 Internal olefins
CH3-CH2-CH=CH2 ------------→ CH3-CH=CH-CH3
CH3 (CH2)17 -CH=CH2-------------→ CH3-(CH2)8-CH=CH-(CH2)8-CH3
Step.5- Metathesis of C4-C10and C16-C40 internal olefins
Catalyst Mo/W/Re on Al2O3
CH3-CH=CH-CH3 + CH3-(CH2)8-CH=CH-(CH2)8-CH3
(i-C4)
↓ (iC20)
2 CH3-CH=CH –(CH2)8-CH3
Step.6 – Fractionation of internal olefins
C10-C14 Internal Olefins
C4-C10 Internal Olefins
C16-C40 Internal Olefins
Separation of C10-C14 olefins & Hydroformylation to alcohols
Shell’s SHOP Process- Stepwise conversions
Step.7 – Hydroformylation of C10-C14 Olefins
C10-C14 Olefins ------------→C11-C15 alcohols
H2+CO
CH3(CH2)7-CH=CH2-------------→CH3(CH2)7-CH2- CH2 –CHO
Co(Co)6
↓ H2
CH3(CH2)7-CH2- CH2 –CH2- OH
Step.8 – Repeat of steps 5,6 & 7 to exhaustion
Shell’s SHOP Process- Block flow diagram
Flow scheme of Shell’s SHOP Process
Ethylene Oligomerization- Ni Complex catalyst
Oligomerization-Addition of ethylene
Dimerization of Propylene & Butadiene, Trimerization of Butadiene &
Co-polymerization of Butadiene & ethylene to yield EPDM rubber
Conversions with butadiene
Olefin metathesis-Process steps
Step.1
Formation of metal alkylidene complexes
Step.2
Formation of metallocyclobutanes
Step.3
Opening of metallocyclobutane to form products
• Majority of metathesis reactions involve heterogeneous
catalysis, Mo/W/Re supported on alumina
• Homogeneous systems are also known
Olefin Metathesis- Mechanism
Alkene Metathesis-General cycle
Different types of Olefin metathesis reactions