Detergents 133
FIGURE 4.9 Idealized structures of neutral salts (soaps).
R
SO 3 )xM
R R
SO 3 )xM
R R
R
R
O)xM
Metal salt of alkylbenzenesulfonic acid Metal salt of alkylnapthalenesulfonic acid Metal salt of alkylphenol
O
O
M
R
OH
O)xM
O O
or
Metal salt of alkylsalicylic acid
Sulfur and methylene-bridged phenates
Y
M
O O
R R
Y
O O
M M
or
X = 1 or 2
Y = S or CH 2
M = Na, Mg, Ca
O
O
O
R
M
P O
O
S
R
M
P S
OO
O O
R R
M
PP
Metal phosphonate Metal thiophosphonate Metal thiopyrophosphonate
FIGURE 4.10 Processes to make basic detergents.
Substrate + metal oxide or hydroxide
MxO M(OH)y
Base
Stoichiometric amount
Neutral salt
Base CO 2 or no CO 2
Basic or overbased salt
Basic or overbased salt
One-step process:
Two-step process:
Substrate + metal oxide or hydroxide
CO 2
or no CO 2
MxO M(OH)y
Excess base
Basic salts = neutral salts MxO, M(OH)y, or MxCO 3
M = Na, Mg, Ca, or Ba
x = 1 and y = 2 for Mg, Ca, and Ba (divalent metals)
x = 2 and y = 1 for Na (monovalent metal)
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