Page 81 - Chemical and process design handbook

Speight_Part II_A 11/7/01 3:16 PM Page 2.22

2.22 MANUFACTURE OF CHEMICALS
of the rich solvent in a column (packed), where the acetylene is fractionated
out, giving a >99% by volume pure product with a 30 to 40 percent yield
from the carbon in the natural gas.
Acetylene is principally used as a chemical intermediate. Acetylene
reacts:

1. With chlorine, to form acetylene tetrachloride (CHCl CHCl ) or acetylene
2
2
dichloride (CHCl=CHCl
2. With bromine, to form acetylene tetrabromide (CHBr CHBr ) or acetylene
2
2
dibromide (CHBr=CHBr)
3. With hydrogen chloride (hydrogen bromide or hydrogen iodide), to form
ethylene monochloride (CH =CHCl) (monobromide, monoiodide), and
2
1,1-dichloroethane (ethylidene chloride (CH CHCl ) (dibromide, diio-
3
2
dide)
4. With water in the presence of a catalyst such as mercuric sulfate
(HgSO ) to form acetaldehyde (CH CHO)
4
3
5. With hydrogen, in the presence of a catalyst such as finely divided nickel
(Ni) heated, to form ethylene (CH =CH ) or ethane (CH CH )
2
3
3
2
6. With metals, such as copper (Cu) nickel (Ni), when moist, also lead (Pb)
or zinc (Zn), when moist and unpurified; tin (Sn) is not attacked but
sodium yields, upon heating, sodium acetylide (CH≡CNa) and disodium
acetylide (NaC≡CNa)
7. With ammoniocuprous (or silver) salt solution, to form cuprous (or sil-
ver) acetylide (HC≡CCu or HC≡CAg) which is explosive when dry and
yields acetylene by treatment with acid
8. With mercuric chloride (HgCl ) solution, to form trichloromercuric
2
acetaldehyde [C(HgCl) · CHO], which yields acetaldehyde (CH CHO)
3
3
plus mercuric chloride when treated with hydrogen chloride