Corrosion inhibitors with improved water solubility and improved film persistence
The invention relates to an additive and to a method of corrosion inhibition on devices for the recovery and transportation of hydrocarbons in crude oil recovery and processing by adding an effective amount of an inhibitor. The inhibitor comprises an alkoxylated quaternary compounds of the formula 1 where R 1 , R 2 are independently groups of the formula —(B)—(O—A) n —O—CO—R 5 or —(A—O) n —(C)—CO—O—R 5 , R 3 is C 1 — to C 30 -alkyl or C 2 — to C 30 -alkenyl, R 4 is an organic radical with 1 to 100 carbon atoms optionally containing heteroatoms, R 5 is an alkyl or an alkenyl, n is a number from 1 to 20, A is an alkylene group, B is an alkylene group, C is a C 1 — to C 6 -alkylene group and X is an anion, used as corrosion inhibitors.
1. A method of inhibiting corrosion at metal surfaces comprising the steps of:
providing a corrosive system which is in contact with a metal surface;
providing compounds of the formula 1
in which
R 1 , R 2 , is a radical of the formula
—(A—O) n —(C)—CO—O—R 5 (3)
R 3 is C 1 - to C 30 -alkyl or C 2 - to C 30 -alkenyl
R 4 is an organic radical having 1 to 100 carbon atoms which optionally contains heteroatoms
R 5 is C 1 - to C 30 -alkyl or C 2 - to C 30 -alkenyl
n is a number from 1 to 20
A is a C 2 - to C 4 -alkylene group,
C is a C 1 - to C 6 -alkylene group and
X is an anion; and
adding said compound of formula (I) to said corrosive system as corrosion inhibitors.
2. The method as claimed in claim 1 , in which A is an ethylene or propylene group.
3. The method as claimed in claim 1 , in which C is a C 2 -to C 4 -alkylene group.
4. The method as claimed in claim 1 , in which n is a number between 2 and 6.
5. The method as claimed in claim 1 , in which R 5 is an alkyl or alkenyl group having 2 to 24 carbon atoms.
6. The method as claimed in claim 1 , in which R 3 is an alkyl or alkenyl group having 2 to 12 carbon atoms.
7. The method as claimed in claim 1 , in which R 4 corresponds to a radical of the formula (4)
in which R 6 is a radical of the formula
—(A—O) n —(C)—CO—O—R 5 (3)
or C 1 - to C 30 -alkyl or C 2 - to C 30 -alkenyl and k is 2 or 3.
8. The method as claimed in claim 1 , in which compounds of the formulae (5) or (8)
are used.
9. A compound of the formula (1),
in which
R 1 , R 2 , is a radical of the formula
—(A—O) n —(C)—CO—O—R 5 (3)
R 3 is C 1 - to C 30 -alkyl or C 2 - to C 30 -alkenyl
R 4 is an organic radical having 1 to 100 carbon atoms which does not contain a heteroatoms
R 5 is C 1 - to C 30 -alkyl or C 2 - to C 30 -alkenyl
n is a number from 1 to 20
A is a C 2 - to C 4 -alkylene group,
C is a C 1 - to C 6 -alkylene group and
X is an anion.
10. The method as claimed in claim 1 , in which said metal surfaces are iron-containing metals.