Lubricant Additives

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)

·