Page 7 - Academic Press Encyclopedia of Physical Science and Technology 3rd Organic Chemistry

P1: GLQ Revised Pages
Encyclopedia of Physical Science and Technology EN001F-4 May 7, 2001 16:19

Acetylene 59

Fixed-bed or fluidized-bed reactors; t = 240–460 C; typ- 2. Replacement Process: Oxyacetylation
◦
ical catalysts, Bi–P–Mo (Sohio), Mo–Vo–Bi (Snam), of Ethylene
Mo–Te–Ce (Montedison–UOP), Se–CuO (BP-Dist.)
1
H 2 C CH 2 + CH 3 CO 2 H + O 2 −−−−−→
2
175−200 C
◦
C. Chloroprene (Neoprene,
H 2 C CHOCOCH 3 + H 2 O
2-Chloro-1,3-Butadiene)
Fixed-bed or fluidized-bed reactors; catalyst, palladium or
1. Acetylene–Vinylacetylene–Hydrogen Chloride
mixture of noble-metal salts deposited on supports.
(Nieuwland–Carothers Process)
CuCl
2C 2 H 2 −−−→ H 2 C CH C CH −−→ F. Vinyl Chloride
NH 4 Cl HCI
1. Acetylene–Hydrogen Chloride
H 2 C CH CCl CH 2 + HCl
(Hydrochlorination)
◦
Liquid-phase process; t = 50–75 C; atmospheric
pressure. C 2 H 2 + HCl −−−−→ H 2 C CHCl
90−140 C
◦
Fixed-bed reactor; catalyst, 10% mercuric chloride on
2. Replacement Process: High-Temperature
carbon.
Chlorination of Butadiene
. 2. Balanced Ethylene–Acetylene (Chlorination–
Cl 2 → 2Cl
Dehydrochlorination)
600 C
◦
.
H 2 C CH CH CH 2 + 2Cl −−−→
C 2 H 4 + Cl 2 → ClCH 2 CH 2 Cl → H 2 C CHCl + HCl
H 2 C CH CCl CH 2 + HCl
C 2 H 2 + HCl → H 2 C CHCl
Overall: C 2 H 4 + C 2 H 2 + Cl 2 → 2H 2 C CHCl
D. Chlorinated Hydrocarbons (Solvents)
1. Chlorination of Acetylene Followed by
Dehydrochlorination 3. Replacement Process: Oxychlorination
of Ethylene
−HCl
C 2 H 2 + Cl 2 → CHCl 2 CHCl 2 −−−→ 1
C 2 H 4 + 2HCl + O 2 → ClCH 2 CH 2 Cl + H 2 O
2
CHCl CCl 2 −→ CHCl 2 CCl 3
Cl 2 C 2 H 4 + Cl 2 → ClCH 2 CH 2 Cl
↓

Cl 2 C CCl 2 ClCH 2 CH 2 Cl → H 2 C CHCl + HCl
1
2HCl + O 2 → Cl 2 + H 2 O
2
2. Replacement Process 1
Overall: 2C 2 H 4 + Cl 2 + O 2 → 2H 2 C CHCl + H 2 O
2
This includes the chlorination of hydrocarbon feedstocks
(methane, ethane, propane, ethylene, propylene), which Fixed-bed or fluidized-bed reactors; oxychlorination,
◦
requires multiproduct technology. t = 450–500 C (atmospheric pressure); catalyst, CuCl 2 –
KCl on Kieselguhr; chlorination of ethylene, t = 50–
◦
140 C(P = 4–10 atm); pyrolysis of ClCH 2 CH 2 Cl,
E. Vinyl Acetate t = 470–540 C(P = 24–25 atm).
◦
These acetylene-based processes are well-tested, high-
1. Acetylene–Acetic Acid
yield, and high-selectivity operations, averaging well over
90% of theory. The extensive use of these processes is
C 2 H 2 + CH 3 CO 2 H −−−−−→ H 2 C CHOCOCH 3 + H 2 O likely once oil-based feedstocks become more expensive
◦
180−210 C
than coal, which will be the preferred raw material for
Fixed-bed reactor; catalyst, zinc acetate on carbon. acetylene production.