AMMONIUM SALT OF AN ALKENYLSUCCINIC HALF-AMIDE AND THE USE THEREOF AS CORROSION INHIBITOR IN OIL AND/OR GAS PRODUCTION TECHNOLOGY

SEL D'AMMONIUM D'UN DEMI-AMIDE D'ACIDE ALCENYLSUCCINIQUE ET SON UTILISATION COMME AGENT ANTICORROSION DANS LA PRODUCTION D'HYDROCARBURES LIQUIDES ET (OU) GAZEUX

English Abstract

An ammonium salt of an alkenylsuccinic half-amide of formula (I) below
<IMG>
in which
R1 denotes H or a C6-C18-alkenyl radical, provided that the radicals R1 are
not both H or both C6-C18-alkenyl,
X denotes a group of the formula -NHR2 or -NR2R3, in which
R2 and R3 denote C1-C6-alkyl, cycloalkyl or a heterocyclic ring attached
to the nitrogen atom via an alkylene chain,
and
A denotes XH or a different primary, secondary, or tertiary amine, for
example an alkanolamine or a polyamine,
and the use thereof as a corrosion inhibitor in oil and/or gas production
technology.

Claims

9
WHAT IS CLAIMED IS:
1 . An ammonium salt of an alkenylsuccinic half-amide of formula (I)
below
<IMG>
in which
R1 denotes H or a C6-C18-alkenyl radical, provided that the radicals R1 are
not both H or both C6-C18-alkenyl,
X denotes a group of the formula (II):
<IMG>
in which q is an integer from 1 to 4, r and p are
independently 1 or 2, and Y denotes CR8 2, NR8 (where R8 is
H or C1-C3-alkyl), O or S, and
A denotes XH or a different amine of the formula
<IMG>
in which
R4, R5 and R6 independently denote H, C1-C6-alkyl (in
which case R5 and R6 may together, form a heterocyclic
ring including the nitrogen atom to which they are
connected), C1-C10-hydroxyalkyl or

10
<IMG>
in which R7 denotes H or C1-C3-alkyl,
n is an integer from 2 to 4, and
m is an integer from 1 to 5.
2. An ammonium salt of the general formula (I) as set
forth in claim 1, in which:
X denotes a group of formula (III)
<IMG>
3. A process for the preparation of an ammonium salt of an alkenyl-
succinic half-amide as claimed in claim 1, wherein
a) a C6-C18-alkene is reacted in an endothermic reaction with maleic
anhydride at a temperature of from 150° to 250°C under standard
pressure conditions or at a temperature of from 150° to 300°C in
an
autoclave,
b) the resulting alkenylsuccinic anhydride is reacted with an amine XH at a
temperature of from 50° to 150°C; over a period of from 1 to 8
hours to
form an alkenylsuccinic half-amide, and
the alkenylsuccinic half-amide is neutralized with an amine A.
4. An anticorrosive agent containing an ammonium salt as
claimed in claim 1 and a dispersing agent.
5. An anticorrosive agent as claimed in claim 4 wherein
the dispersing agent contained therein is a low molecular-
weight or polymeric anionic surfactant, selected from the

11
group consisting of an alkylsulfonic acid, alkylaryl-
sulfonic acid, an arylsulfonic acid and a salt of said
acids.
6. An anticorrosive formulation as defined in claim 4,
where X denotes a group of the formula below:
<IMG>
7. A method of inhibiting corrosion in metals which are
in contact with corrosive oil/water or gas/water mixtures
found in the production, transport and storage of petroleum
and natural gas which comprises: injecting into the
corrosive mixture a corrosion inhibiting amount of an
ammonium salt of an alkenyl succinic half amide of the
formula (I) as defined below,
<IMG>
in which:
R1 denotes H or a C6-C18-alkenyl radical, provided
that the radicals R1 are not both H or both C6-C10-alkenyl,
X denotes a group of the formula (II):
<IMG>

12
in which q is an integer from 1 to 4, r and p are
independently 1 or 2, and y denotes CR8 2, NR8 (where
R8 is H or C1-C3-alkyl), O or S, and
A denotes XH or a different amine of the formula:
<IMG>
in which
R4, R5 and R6 independently denote H, C1-C6-alkyl (in
which case R5 and R6 may together form a heterocyclic
ring including the nitrogen atom to which they are
connected), C1-C10-hydroxyalkyl or
<IMG>
in which R7 denotes H or C1-C3-alkyl,
n is an integer from 1 to 4, and
m is an integer from 1 to 5.
8. A method of inhibiting corrosion in metals which are
in contact with corrosive oil/water or gas/water mixtures
found in the production, transport and storage of petroleum
and natural gas which comprises: injecting into the
corrosive mixture a corrosion inhibiting amount of an
ammonium salt of the formula (I) as defined in claim 7,
where X denotes a group of the formula (III);
<IMG>

13
9. A method as defined in claim 7, wherein the corrosive
medium contains CO2 and/or H2S.
10. A method as claimed in claim 9, wherein the corrosive
medium also contains elemental sulfur.

Description

I~~~~ AKTIENfiESELLSChIAFT O.Z. ooso/42171
~rnr~toniur~ Spit of an Aikeny6suc~inic i°9~If-~nnid~
end the lJse Thereof as corrosion inhibitor
in ail and/or has production ~e~hnol~gy
The inventian relates to ammonium salts of alkenyl :>uccinic half-amides and
to the use thereof as corrosion inhibitors in oil andlor gas production tech-
nology to combat corrosion by media containing CCf2 and HZS and possibly
elemental sulfur.
In the production of petroleum and natural gas there usually occurs an
oil/water or gas/water mixture which in the case of oil may contain up to
about 98% of water.
,° The salinity of the entrained water may be extremely low or
conversely, the
water may comprise a saturated salt solution. HZS and/or C02 are also
present.
The combination of HZS and/or COZ and the water has a strong corrosive
,5 action on metals used in petroleum and natural gas plants. This action is
intensified by the presence of elemental sulfur.
It is common practice to inject a solution or dispersion of corrosion
inhibitor
into the corrosive medium to be handled in the production, transport aad
z° storage of petroleum or natural gas. By this means the surface of
the metals
contacted by the medium is coated with a protective film.
Hitherto, certain imidazoline salts have been proposed for this purpose (cf.
EP 0,065,191 and EP 0,103,737), but these have an unsatisfactory
z5 anticorrosive effect against C02 and/or hlzS, especially in the presence of
elemental sulfur, as discussed in Environment Treatment ~ Control, Feb.
1990, pp. 43 to 52.
Neither do amine salts of maleamide acids, as described in ~P 0,106,234,
3° possess adequate anticorrosive properties for this purpose.
Oil-soluble amidoamine salts of alkenylsuccinic acids and the use thereof as
corrosion inhibitors in water-in-oil emulsions such as occur in oil production
are described in EP 0, 359, 043.
~IVater-soluble alkanolamine salts of alkenyisuccinic acids, described in DE

~~~~ AKTIEN~ESELLSCHAFT 2 O.Z, ooso/42171
2,943,963-C2 as being effective as corrosion inhibitors in metal working,
also show inadequate anticorrosive action in the systems under consideration
here.
It is thus an object of the invention to provide improved, preferably water-
soluble inhibitors for use in corrosive media such as occur in petroleum
and/or natural gas production, to counteract the corrosive action of CrJ~
and/or H2S, especially when elemental sulfur is present.
,o We have now found that ammonium salts of alkenylsuccinic half-amides of
formula (I) below
o
R~ C-O~A~-H
NCH/ (I)
,s
/CH ~
R~ C=0
I
X
in which
ZU
30
R~ denotes H or a Ce-C~~-aikenyl radial, provided that the radicals R' are
not both H or both Cg-C~e-alkenyl,
X denotes 'a group of the formula -i~HR2 or -fVR2R3, in which
R2 and R3 denote C~-CB-alkyl, cycloalkyi or a heterocyclic ring attached
to the nitrogen atom via an alkylene chain,
and
A denotes XH or a different amine of the formula
R5
Rn-~ /
ERs
in which
R4, R5 and Rg independently denote H, C~-Cs-alkyl (in which case R5
and R6 may together form a heterocyclic ring enclosing
the nitrogen atom), C~-Cao-hydroxyaikyl or
b

CA 02060580 2002-10-29
3
--~(CH2)~-~N--~(CH2)~-~1H2 ,
R~
in which R~ denotes H or C~-C3-alkyl,
n is an integer from 2 to 4, and
m is an integer from 1 to 5,
are particularly well suited for use as water-soluble corrosion inhibitors in
oil
and/or gas production plants.
A particularly suitable representative of the group X is a group of the
formula (1l> below
H
--N\ / (CH2)r \
(CH2)Q--N~ ~Y (1l),
(CH2)p
in which q is an integer from 1 to 4, r and p are independently 1 or 2, and
Y denotes CRa2, NR$ (where R$ is H or C~-C3-alkyl), O or S.
The present invention also concerns a method of inhibiting
corrosion in metals which are in contact with corrosive
20 oil/water or gas/water mixtures found in the production,
transport and storage of petroleum and natural gas which
comprises: injecting into the corrosive mixture a corrosion
inhibiting amount of an ammonium salt of an alkenyl
succinic half amide of the formula (I) as defined below,
0
R ~ /C-O~A~-H
i H (I)
/CH ~
R~ C=0
X

CA 02060580 2003-03-31
a
in which:
Rl denote; H or_ a C6--c~'1g-alkenyl radical, provided
that the radicals R~- :ire not both H or both C6-Cl0-alkenyl,
X denotes a grc.-~.y> of t:he formula ( I I )
H
-i~J~ (CH2)r v
(CH2)q ~~~, j Y ( I I ),
(CH2)p
in which q is a.n integer from 1 to 4, r and p are
independently J cr ?, and Y denotes CR8~, NR8 (where
R8 is F~ or C~_-C j--alkyl) , O or S, and
A denotes XH or a d.i.ff_erent amine of t-me formula:
R5
R4-N ,,
,,~Rs
in which:
R4, R-'' and R6 independe~zt'_y denote H C1-C6-alkyl (in
which case R5 <:~n.d RE~ may toger_iner form a heterocyclic
ring including the nit:rc~g~n atone to which they are
connected) , Cl--':1,,~-iaydro~:ya:lk:~,r:l- or
..-~-ICH2)n~(CH2)n.-NH2
R7
in which R~ der~ot--cps H c>r ~l--C'_s--a~~.kyl,
n is an integer from .L to 4, and
m is an inl~ege.r ,=rom 1 to I.
It is part:~cularly adlrantagec~Lr~~ whc_n the group X or the
above formLa=La ( T ) i- a rad:icai c>f fo:rrnula ( I I I ) below

CA 02060580 2003-03-31
3b
H
CH2--~H2--~l\ ~N H ( I I I ).
The counterion A°-H is derived either from the amine XH used to
form the
half-amide or from a different amine of the formula
R5
R4-N.
.v
Rs
~U
in which R4, R' and Rs have the meanings stated above. Such amines are
NH3 or primary, secondary, ar tertiary amines, eg butylamine or dibutylamine,
or alkanolamines, eg ethanolamine, diethanolamine, or triethanolamine, or
they are polyamines such as diethylenetriamine or dipropylenetriamine.
The alkenylsuccinic amides forming the basis of the salts of the invention
are obtained by the following method:
,.'
,r

~~SF AKTIENLiESELLSCHAFT n O.Z, ooso/n2171
1. The endothermic reaction, known per se, between malefic anhydride and
the appropriate olefin is carried out at a temperature of from 150° to
250°C under standard pressure conditions or at a temperature of from
150° to 300°C in an autoclave das described in, say, DE A 3,
411, 53 ~ )
and
2. the alkenylsuccinic anhydride thus obtained is reacted with the amine XH
to form the aikenylsuccinic half-amide at a temperature of from 50° to
150°C, preferably from 50° to 120°C, for example in
substance or in an
,o aromatic solvent.
The amide/ammonium salts of the invention are obtained therefrom by
reaction with the amines A, preferably also at a temperature of from
50° to
120°C. When the same amine components are used for XH and A, the
,3 preparation of the amide/ammonium salt may be effected directly by
reacting the alkenylsuccinic anhydride with the amine in a ratio of 1:2.
Particularly noteworthy examples of amines XH are aminoalkylpiperazines and
aminoalkylmorpholines, for example aminoethylpiperazine.
2a
The inhibitors thus obtained exhibit excellent anticorrosive action against
HZS
and COa, and in particular, no impairment of this action is caused by the
presence of elemental sulfur.
25 The efificacy of the inhibitors, particularly in the presence of elemental
sulfur,
can be increased by formulating the products with surface-active
substances.
Suitable dispersing agents are: low molecular-weight or polymeric anionic
3o surfactants and dispersing agents, particularly alkylsuffonic acids,
alkylarylsul
fonic acids, arylsulfonic acids, and the salts thereof.
The corrosion inhibitors of the invention are used in amounts varying from 3
to 1000 ppm depending on the composition of the corrosive modium. To
3s combat corrosion by COx or C02/H2S only, the addition of inhibitor formula-
tion is preferably from 5 to 50 ppm, and in the presence of elemental sulfur
it is preferably from 100 to 300 ppm.
The invention is illustrated by the following Examples.

;p~ 20~~~~Q
~~~F AKTIENOESELLSCHAFT 5 O.Z.0050/42171
1. Ammonium salt synthesis
Example 1
2.3 g of phenothiazine were added to a reaction mixture o~f eguimolar
amounts of tetrameric propylene (463 g) and malefic anhydride (269.5 g),
and the whole was stirred at a temperature of from 180° to 200°C
over a
period of from 25 to 30 hours. Unconverted educts were then distilled off at
175°C under a high vacuum.
,0
A mixture of 342 g of the resulting alkenylsuccinic anhydride and 400 mi of
xylene was heated to 80°C, and 368 g of aminoethylpiperazine were added
dropwise at this temperature. Stirring was continued 'for 3 hours at the same
temperature, and a portion of the solvent was removed under a water jet
,5 vacuum. There was obtained a black viscous product in a yield of 608 g
and having a content of 85% of active ingredient.
The tetrameric propylene used was the C12 cut from the olefin oligomer-
ization.
z0
as
35
Composition (GC/MS analysis): C9 0.5%; Clo 5.8%; C11 20.7%; C12 70.9%;
C13 2.1 %.
The composition and isomer ratio may vary slightly from batch to batch.
The IR spectrum clearly indicates that the reaction product obtained from
the alkenylsuccinic anhydride and aminoethylpiperazine is an ammonium salt
of the alkenylsuccinic half-amide, since it shows both characteristic amide
bands and -C02 bands. Imide formation is also indicated.
Characteristic IR bands:
Amide: 1680 to 1630 and '1570 to 1515 cm~l
C00-: 1610 to 1550 cm°1
Imide: approx. 1770 to approx. 1700 cm-' .
The ammonium salts of the invention can be isolated from the reaction
solution by conventional means.
Exarr~pBe 2
387 g of trimeric butylene (prepared by trimerization of n-butane) and 225 g
b

II~~~~AKTIENQESELLSCHAFT ' 6 ~',~ O.Z.005p/~2~~~
of malefic anhydride were placed in an autoclave. A nitrogen pressure of 5
bar was established, and the reaction mixture was stirred for 10 hours at a
temperature of 200°C.
595 g of the reaction product were dissolved in 300 ml of xylene, and the
solution was heated to 80°C. 578 g of aminoethyipiperazine were added
dropwise at this temperature. The reaction mixture was stirred for 4 hours
at the same temperature, after which a portion of the solvent was removed
under a water jet vacuum to give the desired corrosion inhibitor as a dark
,° colored viscous oil.
Example 3
Example 2 was repeated except that a linear C»-olefin was used in place
,5 of trimeric butylene.
Exxaraiple ~
An alkenyisuccinic anhydride was prepared frorr~ trimeric butylene and
Zp malefic anhydride as described in Example 2. Unconverted olefin and
anhydride were removed at 100°C/30 mbar.
198 g (0.75 mole) of this product were dissolved in xylene, and the solution
was heated to 100°C. 97 g (0.75 mole) of aminoethylpiperazine were
slowly
25 added dropwise at this temperature. The reaction solution was then stirred
for about 5 hours at 90-100°C. The solvent was then removed to give 290
g of a black viscous reaction product.
3o In order to neutralize the free carboxyl groups, 101 g (0.2 mole) of this
product wore reacted with 26 g (0.2 mote) of diethylenetriamine in xylene at
80°C. The product was concentrated in a rotary evaporator to about 83%
to
give the corrosion inhibitor of the invention in the form of a black viscous
oil.
2. Examples of application
The inhibitor formulations were tested dynamically using the "wheel-test"
described, for example, in EP A 0,359,048, which is a common method of
4° testing corrosion inhibitors in petroleum and natural gas production
plants.
The test coupons were large steel plates of ST 37 which had previously
been thoroughly ground with emery, degreased with toluene, and weighed.

I~~~FAKTIENQESELLSCHAFT 7 0.2.0050/42171
The coupons were then placed in the corrosive medium and were agitated
therein for 16 hours at 80°C (40 rpm via a shaft coupled to rotate the
test
vessel). The specimens were then cleaned with an inhibited acid, degreased,
dried, and weighed in order to determine the weight loss. The results were
compared with reference values obtained in a test carried out without the
addition of inhibitor.
,°
The anticorrosive factor Z in percent was calculated from the weighings
using the following equation:
z = ~° G G~ x 100 [~o~
0
where G° is the rate of corrosion without inhibitor and G~ is the rate
of
corrosion with inhibitor.
The results are listed in the Tables below.
TABLE 1 - Anticorrosive factor Z [%J
Medium:
z 10% white 90% brine (3! NaCI?; and/or H25
spirit, saturated with C02
Saturated with:C02/CO2 CO2/H2S
Inhibitor dosage:3 ppm 7.5 ppm 3 ppm 7.5 ppm
Product from
Example 1 46 78 68 79
Example 2 51 75 74 80
F.~cample 3 61 64 76 81
Example 4 80 80
b

~~~FAKTIENQESELLSCHAFT 8 - O.Z.0050/421%1
TABI_~ 2
Medium: approx. 6.5 ml of brine saturated with H2S, approx. 193,5 ml
of brine saturated with C02 , 0.5 g of ground sulfur
Inhibitor dosage:150 ppm
Product from Dispersing agent Anticorrosive
factor Z L%J
Example 1 - 50
Example 1 10! oiigomeric aryl sulfonate 82
(Tamol 941 Oa)
Example 1 15% alkylbenzene sulfonate 78
(ALBS)
,0 Example 2 10% oligomeric aryl sulfonate 85
Example ~ 15% ALBS 78
Example 3 15% ALBS 80
Example 3 10% oligomeric aryl sulfonate 75
Examale 4 15% ALBS 80
,5
Comparative Examples
Medium: approx. 6.5 ml of brine saturated with H2S, approx. 193.5 ml of
brine saturated with C02, 0.5 g of ground sulfur
Z° Inhibitor dosage: 150 ppm
Product Dispersing agent Anticorrosive factor [%7
1. acetate of a long-chain - 17
imidazoline
2. amido-imidazoline plus - 33
Z5 dimerized/trimerized
fatty acid
3. amido-imidazoline - 25
4. as for 1 10% oligomeric aryl 0
sulfonate
3° 5. as for 1 15% alkylbenzene 12
sulfonate
It can be seen from the above results that the commercially available
corrosion inhibitors are distinctly less effective and that the addition of
35 dispersing agents to said prior art corrosion inhibitors has no
advantageous
effect.
By comparison, the ammonium salts of the invention are found to be highly
effective corrosion inhibitors.

Representative Drawing