A series of water-soluble, or at least water-dispersible, corrosion inhibiting solutions are disclosed which contain about 2 ppm to about 70%, preferably about 3 ppm to about 200 ppm, of an ethoxylated, propoxylated alkylphenol amine represented by the formula: ##STR1## wherein R is hydrogen or an alkyl group containing about 5 to about 12 carbon atoms, R' is an alkyl group containing about 5 to about 12 carbon atoms, x equals about 1 to about 20, z equals about 1 to about 20, a equals about 1 to about 20, and b equals about 1 to about 20. The salt reaction products of the instant alkoxylated amine and an organic acid selected from the group consisting of hydroxyacetic acid, a fatty acid, a dicarboxylic acid, a dimer-trimer acid, an acidic phosphorus containing compound, and mixtures thereof are also effective in controlling sour and sweet corrosion. A method is also disclosed for protecting metal from corrosion by contacting the metal with an effective amount of the amine or the amine/acid reaction products, in a continuous or batch treatment.

BACKGROUND OF THE INVENTION 
The invention relates to organic inhibitor treating solutions and a method 
for using such solutions to reduce corrosion from the harsh fluid 
environments encountered in the oil field. More particularly, the 
invention concerns treating solutions containing an ethoxylated, 
propoxylated alkylphenol amine, which are effective in reducing sweet and 
sour corrosion. 
Corrosion that occurs in an oil field environment is extremely complex and 
tends to attack all manner of metal equipment above and below ground. The 
principle corrosive agents found in the well fluids include hydrogen 
sulfide, carbon dioxide, oxygen, organic acids and solubilized salts. 
These agents may be present individually or in combination with each 
other. Valves, fittings, tubing, pumps, precipitators, pipelines, sucker 
rods, and other producing equipment are particularly susceptible. Deposits 
of rust, scale, corrosion byproducts, paraffin and other substances create 
ideal environments for concentration cells. Carbon dioxide and hydrogen 
sulfide induced pitting is encouraged by such deposits. Acidic condensate 
that collects on metal tubing will also cause pitting. Extreme 
temperatures and pressures in downhole environments further accelerate 
corrosion. 
Very often as oil fields mature and enhanced recovery methods such as water 
flooding and miscible flooding are instituted, the concentrations of 
hydrogen sulfide and carbon dioxide in the well fluids increase 
dramatically. This increase in concentration and the resultant increase in 
sweet corrosion or sour corrosion may make older oil fields economically 
unattractive due to excessive corrosion costs. 
Various surfactants have been employed for many years to inhibit corrosion 
or to improve the performance of certain organic corrosion inhibitor 
systems. Surfactants are generally added to inhibitor systems to perform 
the different functions of (1) solubilizing the corrosion inhibitor or 
other active ingredients, (2) clean the surface of the metal to be 
protected or treated, and (3) improving the penetration of the active 
ingredients into the microscopic pores of the metal. 
Ethoxylated alcohols and ethoxylated amines of various structures are 
common sufactants employed in corrosion inhibition systems. Six examples 
of such surfactant compounds are provided by U.S. Pat. Nos. 3,038,856; 
3,110,683; 3,310,496; 3,623,979; 4,435,361 and 4,420,414. No. 3,110,683 
discloses a series of alkylated, halogenated, sulfonated, diphenyl oxides 
and No. 3,623,979 discloses a series of imidazolinyl plymeric acid amides. 
The use of dicyclopentadiene sulfonate salts is disclosed in 4,435,361. 
Ethoxylated tertiary amines represented by the formula 
##STR2## 
wherein x is about 9-11 and the sum of (y+z) is 2-50 are described and 
claimed in No. 4,420,414. The latter four of the above corrosion 
inhibition patents disclose oil-dispersible inhibiting systems which form 
a film over the metal parts to be treated. They are not water soluble 
systems. 
A water-dispersible corrosion inhibiting system disclosed in U.S. Pat. No. 
4,636,256 contains ethoxylated propoxylated alkylphenol amines of the 
formula 
##STR3## 
wherein R is an alkyl chain with 5 to 12 carbon atoms, x is 3 to 15 and z 
is 2 to 10. 
A copending patent application, Ser. No. 07/136,064, filed Dec. 21, 1987, 
also discloses the use of an oil soluble to water-dispersible corrosion 
inhibiting system with alkoxylated alkylphenol amines. It teaches the use 
of amines with the formula 
##STR4## 
wherein R and R' are alkyl chains containing about 5 to about 12 carbon 
atoms, x equals about 1 to 10, and z equals about 2 to 20. 
SUMMARY OF THE INVENTION 
A series of water soluble, or water-dispersible corrosion inhibiting 
solutions are disclosed which contain an ethoxylated, propoxylated 
alkylphenol amine represented by the formula 
##STR5## 
wherein R is hydrogen or an alkyl group containing about 5 to about 12 
carbon atoms, R' is an alkyl group containing about 5 to about 12 carbon 
atoms, x equals about 1 to about 20, z equals about 1 to about 20, a 
equals about 1 to about 20, and b equals about 2 to about 20. It has been 
discovered that the use of these particular alkoxylated alkylphenol amines 
dramatically reduces oil field corrosion rates. 
A preferred corrosion inhibiting solution of the invention contains about 2 
ppm to about 70% by volume of the alkoxylated alkylphenol amine in a 
solvent which may be water, brine, an organic solvent such as alcohol or 
mixtures of organic solvent and water. The alkoxylated alkylphenol amine 
may be used in a continuous treatment wherein the metal to be protected 
from corrosion is contacted with about 3 to about 200 ppm of the amine in 
a continuous treatment or in a batch treatment with higher concentration 
levels. The amine can be stored and shipped in solutions with 
concentrations ranging up to and greater than 70% alkoxylated alkylphenol 
amine by volume. 
It is most preferred to react the alkoxylated alkylphenol amine with an 
organic acid selected from the group consisting of hydroxyacetic acid, a 
fatty acid, a dicarboxylic acid, a dimer-trimer acid, an acidic phosphorus 
containing compound, and mixtures thereof to form a salt and then use that 
salt in a continuous exposure treatment. Simple mineral acids may be 
substituted for the organic acid, but results may not be as good. Unless 
otherwise noted, it should be presumed that a discussion of either the 
acid/amine reaction product or the amine will also apply to the other. Of 
course, the alkoxylated alkylphenol amines may also be combined with other 
organic corrosion inhibiting systems to produce excellent results. 
Metal equipment can be protected through the use of the corrosion 
inhibiting solutions of the present invention by contacting metal with an 
effective amount of inhibiting solution containing the alkoxylated 
alkylphenol amines of the instant formula or the reaction product of said 
amines and an organic acid in a continuous exposure treatment. Solution 
concentration for continuous exposure treatment preferably should be in 
the range of about 3 ppm to about 200 ppm. For batch treatment, solution 
concentrations hould be in the range of about 2% to about 20% by volume. 
DETAILED DESCRIPTION 
Perhaps the most costly problem in an oil field environment is corrosion of 
piping and equipment due to sweet and sour corrosion. It has been 
discovered that the additions of small amounts of a particular group of 
ethoxylated, propoxylated alkylphenol amines effectively inhibits 
corrosion from both carbon dioxide and hydrogen sulfide. 
Although this invention comprises corrosion inhibiting solutions containing 
about 2 ppm to about 70% by volume of the instant amine, the amine is 
preferably delivered to the corrosion sites in a continuous treating 
solution containing about 3 ppm to about 200 ppm of the amine having the 
formula 
##STR6## 
wherein R is hydrogen or an alkyl group containing about 5 to about 12 
carbon atoms, R' is an alkyl group containing about 5 to about 12 carbon 
atoms, x equals about 1 to about 20, z equals about 1 to about 20, a 
equals about 1 to about 20, and b equals about 1 to about 20. A batch 
treating solution with an amine concentration of about 2% to about 20% by 
volume is also effective. 
The instant amines most preferred for use in the invention corrosion 
inhibiting solutions are those amines of the given formula wherein either 
R or R' is an alkyl group containing about 7 to about 10 carbon atoms, x 
equal about 4 to about 10, z equals about 2 to about 5, a equals about 1 
to about 20, and b equals about 1 to about 20. The alkyl groups containing 
about 5 to about 12 carbon atoms are necessary to add non-polar material 
to the compound. The elimination of the alkyl groups makes the compounds 
too hydrophilic. It is believed that there would not be enough non-polar 
material to keep the aqueous phase off the metal, if the alkyl groups were 
absent. When R and R' are both alkyl groups, water solubility dramatically 
decreases. 
The isomeric positions of the alkyl groups and the chain of alkylene oxide 
groups on the aromatic ring are thought to be unimportant. The method of 
synthesis of the amine will most likely determine the positions of 
aromatic ring substituents. 
The structure of the amine may be varied to tailor the compound to 
individual requirements. When few ethylene oxide groups are employed in 
the compound, the compound loses some water solubility. It may be 
necessary to employ a mixed brine and organic solvent. As the number of 
propylene oxide groups increases, the compound becomes more oil soluble 
and less water soluble. 
The amine compounds used in the invention corrosion systems may be prepared 
by the reaction of ethylene and propylene oxide with an alkylphenol in 
varying ratios. The resulting compound is then subjected to reductive 
amination in the presence of ammonia and hydrogen to produce the instant 
amine. 
The invention solution may be employed in both general methods of 
inhibiting solution treatment, continuous injection and batch. Either 
method, continuous injection or batch, permits the organic inhibitor 
solution containing the instant alkoxylated amine to contact the metal to 
be protected and form an organic barrier over the metal. 
The effectiveness of a given organic inhibitor system generally increases 
with the concentration, but because of cost considerations, most solutions 
when fully diluted in their working environment must be effective in 
quantities of less than about 0.01% by weight (100 ppm). The invention 
solution is effective throughout the range of about 3 ppm to about 200 ppm 
in a continuous injection method, with higher concentrations generally 
producing greater protection. Although it may not be cost effective, the 
invention inhibiting solution may be employed in the field with 1% by 
volume of the amine or acid/amine reaction product. 
If a batch method is employed, a slug of inhibiting solution containing the 
instant alkoxylated amine should be injected into a closed system with a 
concentration of preferably about 2% to about 20% by volume of inhibiting 
solution in diluent. The diluted inhibiting solution should be allowed to 
remain in contact with the metal to be protected for sufficient time to 
form a durable film. The contact time period is about 2 to about 24 hours, 
preferably at least 12 hours, most preferably 24 hours. Afterwards, normal 
production or flow of fluids should be resumed, flushing out excess 
inhibitor solution. The batch treatment should be repeated when necessary 
to maintain film durability over the metal to be protected. 
It is desirable to store and transport the invention corrosion inhibiting 
solution with higher amine or organic acid reaction product 
concentrations, such as about 1% to about 70% by volume, preferably about 
15% to about 60% by volume of the solution. The acid/amine reaction 
products are generally less soluble in water than the amines of the 
instant formula. But all are dispersible in water alone at the treating 
concentrations of about 2 ppm to about 20%. The preferred solvent 
environment is a mixed water and organic solvent. Although these corrosion 
inhibitors generally work best in brine or mixed organic and brine 
environments, transportation and storage solutions can be either organic 
solvent or mixed organic and water solvent. 
When higher concentrations are used for storage an transportation, it may 
be necessary to add some alcohol to the water solvent to maintain the 
active ingredient in solution. With only water as a solvent at these 
higher concentrations, settling problems may occur which would make 
dilution and use in the field quite difficult. For handling ease and to 
save volume and shipping costs, concentrations are preferably about 15% to 
about 70% water, about 5% to about 70% alcohol, and about 15% to about 60% 
of active ingredient by volume of solution. 
In higher concentrations of about 15% to about 60% by volume of the instant 
amine, it is preferred tha the solvent contain at least some portion of a 
lower molecular weight alcohol to maintain solubility, or at least 
dispersion, of the amine. This avoids physical handling problems in the 
field. Practically any alcohol may be used as a solvent, but lower 
molecular weight alcohols are preferred, primarily because of their low 
cost. Isopropanol, methanol, and ethylene glycol are three of the most 
preferred alcohol solvents. 
For example, a drum containing a solution of 25% by volume of the instant 
amine in 75% solvent should preferably have a solvent system of at least 
15% alcohol in 85% water. With the water to alcohol ratio of 90/10, 
solubility may be achieved, but phase separation may occur. Thus, a 
water/alcohol ratio of at least 85/15 is desired. 
Isopropanol is a preferred alcohol solvent because of its cost. Methanol, 
ethanol, propanol, butanol and pentanol may all be used. Ethylene glycol 
and propylene glycol are also preferred alcohol solvents because they can 
be mixed with isopropanol or the other alcohols to lower the flash point 
and pour point of the solution. Consequently, a representative 
concentrated solution might be 15% amine in a 75% solvent of 5% 
isopropanol, 15% ethylene glycol and 55% water. Of course, much larger 
amounts of alcohol may be employed, but water is preferred because of its 
cost. 
The ethoxylated, propoxylated alkylphenol amine may be placed in a solvent 
system as is, or reacted with an acid selected from the group consisting 
of hydroxyacetic acid, a fatty acid, a dicarboxylic acid, a dimer-trimer 
acid, an acidic phosphorus containing compound, mineral acids or mixtures 
thereof. Organic acids are preferred. When this acid/amine reaction is 
carried out at ambient temperature, a salt is formed which is effective in 
controlling corrosion when employed in approximately the same 
concentrations as the alkoxylated alkylphenol amine itself, preferably 
about 3 ppm to about 200 ppm in continuous treatment, or about 2% to about 
20% by volume in batch treatment. 
The organic acid and amine are reacted in the stoichiometric proportions of 
about 0.65/1 acid/amine ratio to about 1/0.6 acid/amine ratio, most 
preferably about 0.9/1 to about 1/0.7 acid/amine ratio. Formulations with 
excess acid are preferred because of cost considerations. 
Viscosity problems were encountered with some 1/1 acid/amine reaction 
products and increased as the acid/amine ratio decreased. These can be 
solved by adding a small amount of a viscosity reducing additive to the 
solution, such as a low molecular weight sulfonate. 
The organic acids preferred for reaction with the amine of the instant 
formula are hydroxyacetic acid, fatty acids having about 16 to about 20 
carbon atoms, dicarboxylic acids having about 19 to about 23 carbon atoms, 
various dimer-trimer acids, and phosphate esters having a alkylphenol 
group with about 2 to about 20 ethylene oxide groups which behave like 
acids. Other acidic phosphorus containing compounds such as phosphonates 
may also be used to good effect. 
Examples of the organic acids include: Pamak WCFA, a trademarked fatty acid 
having about 16 to 18 carbon atoms and an acid number of 178 sold by 
Hercules, Inc.; Arizona 7002, a trademarked dimer-trimer acid with an acid 
number of 142 sold by Arizona Chemical Co.; Emery 1022, a trademarked 
dimer-trimer acid having about 80% dimer acid and 20% trimer acid, sold by 
Emery Industries and having an equivalent weight of 291; Diacid 1550, a 
trademarked dicarboxylic acid having about 21 carbon atoms and an 
equivalent weight of about 303 sold by Westvaco Corp.; Century D-75, a 
trademarked dimer-trimer acid with about 16 to about 18 carbon atoms and 
an equivalent weight of 379 sold by Union Camp Corp. (Century D-75 
averages about 24% monomer, 33% dimer, and 43% trimer or higher); Westvaco 
L-5, a trademarked tall oil fatty acid having about 16 to 18 carbon atoms 
and equivalent weight of 295 sold by Westvaco Corp.; Wayfos M-100, a 
trademarked organic phosphate ester with an nonylphenol group having 10 
ethylene oxide groups and an equivalent weight of about 416 sold by 
Phillip A Hunt Chemical corp; Wayfos D-10N, a trademarked organic 
phosphate ester with an equivalent weight of about 625 sold by Phillip A. 
Hunt Chemical Corp.; and glycolic acid. 
The amine of the formula can also be reacted with an acidic phosphorus 
containing compound which at low concentrations of about 3 ppm to about 
200 ppm is effective in controlling scale as well as sour and sweet 
corrosion. Two examples of such compounds are phosphonates and phosphate 
esters. 
A monoalkylphenol amine was reacted with Wayfos M-100, a phosphate ester 
with a nonylphenol group having ten ethylene oxide groups. The reaction 
product gave over 90% inhibition against scale and sour corrosion and over 
85% inhibition against sweet corrosion all at concentrations below 50 ppm. 
In fact, 92% calcium sulfate scale inhibition was achieved at only 13 ppm. 
The amine/phosphate ester salt prevented scale but the amines alone were 
ineffective. 
The corrosion inhibiting solutions of the invention which contain the 
instant ethoxylated, propoxylated alkylphenol amines may be employed in 
different locations in the oil field. Since the solutions offer 
substantial improvement over present inhibitor systems, they may be used 
to protect downhole piping and equipment in situations such as subsurface 
water injection for pressure maintenance, water disposal systems or 
drilling and production applications, as well as in above-ground, oil or 
water flow lines and equipment. 
The invention solution may be employed to inhibit corrosion by continuous 
injection or batch treatment. In a continuous injection treatment, the 
active ingredient of the corrosion inhibiting solution is maintained at 
the required levels of treatment, preferably about 5 ppm to about 300 ppm, 
in areas where corrosive fluids contact the metallic parts desired to be 
protected. In a batch treatment, the instant corrosion inhibiting system 
is injected at a concentration of about 2% to about 20%, and allowed to 
contact the metal to be protected for preferably at least 12 hours, most 
preferably at least 24 hours, before being exposed to production fluids. 
At present, an industry established procedure for testing oil field 
corrosioninhibitors does not exist. because of widely varying corrosion 
conditions in the oil field, it is impractical to establish a universal 
standard laboratory test. but it is desirable to have tests that are 
easily duplicated and can approximate the continuous type of liquid and 
gas exposure that occurs in wells and flow lines in the oil field. One 
test simulating field usage has achieved some following in the industry. 
The continuous exposure procedure set forth in January 1968 issue of 
"Material Protections" at pages 34-35 was followed to test the subject 
invention. The test offers an excellent indication of the ability of 
corrosion inhibitors to protect metals immersed in either sweet or sour 
fluids. 
A second test was generally followed for evaluating scale inhibition 
against gypsum or calcium sulfate deposition. The test is described in 
detail in "Corrosion", Vol. 17 (5), pp 232-236 (1961) with modifications 
described below. 
The following examples will further illustrate the novel corrosion treating 
solutions of the present invention containing said alkoxylated alkylphenol 
amines. These examples are given by way of illustration and not as 
limitations on the scope of the invention. Thus, it should be understood 
that materials present in the corrosion treating solutions may be varied 
to achieve similar results within the scope of the invention.

EXAMPLES 
General Test Procedure 
The metal specimens were immersed in sweet or sour fluid environments for 
seventy-two (72) hours to approximate continuous exposure conditions in 
the oil field. The sweet fluid test environment was established by gassing 
the test solution with carbon dioxide. A sour fluid test environment was 
created by bubbling hydrogen sulfide through the test solution. The 
specimens were tested in both carbon dioxide and hydrogen sulfide 
environments with and without the claimed amines. 
The metal test specimens were cold-rolled, mild steel coupons which 
measured 3 inches by 0.5 inches by 0.005 inches. These coupons were 
initially cleaned in order to remove any surface film, dried and then 
weighted. 
Four ounce glass bottles were filled with two types of test solutions. the 
first simulated an oil-brine environment and consisted of 10 milliliters 
of depolarized kerosene, 90 milliliters of a 10% synthetic brine and 1 
milliliter of dilute (6%) acetic acid. The synthetic brine contained 10% 
sodium chloride and 0.5% calcium chloride by weight. The second test 
solution simulated a brine environment and was composed of 100 milliliters 
of the same 10% synthetic brine and 1 milliliter of dilute acetic acid. The 
oil-brine and brine test solutions were then gassed for 5 to 10 minutes 
with carbon dioxide to create a sweet test environment or hydrogen sulfide 
to create a sour test environment. The solution gassing was designed to 
remove any dissolved oxygen as well as create the sweet or sour 
environment. Next, a measured concentration of the amine or acid/amine 
reaction product was placed in the bottles. 
The steel test coupons were then placed within the bottles. The bottles 
were capped and mounted on the spokes of a 23 inch diameter, vertically 
mounted wheel and rotated for 72 hours at 30 rpm inside an oven maintained 
at 49.degree. C. The coupons were removed from the bottles, washed and 
scrubbed with dilute acid for cleaning purposes, dried and weighed. The 
corrosion rate in mils per year (mpy) was then calculated from the weight 
loss. One mpy is equivalent ot 0.001 inches of metal lost per year to 
corrosion. Additionally, the test coupons were visually inspected for the 
type of corrosive attack, e.g., hydrogen blistering, pitting and crevice 
corrosion or general corrosion. 
The laboratory tests for calcium sulfate scaling were performed with the 
testing apparatus of the "Corrosion" article mentioned above, the 
disclosure of which is incorporated herein by reference. The procedure 
discussed in the Corrosion Article was loosely followed, with some 
differences as noted below. The apparatus deposits scale on heated 
stainless steel rotors that turn in water solutions of the scale forming 
minerals of calcium sulfate. Cylindrical electric heaters were mounted in 
the shafts to fit inside the rotor tubes which are slip fitted onto the 
shafts. A chain and pulley arrangement drove the rotor shafts from the 
variable speed motor. Line voltage for the variable speed motor was 
controlled by a variable transformer and a rheostat was employed to 
control the heaters. 
In preparation for the tests, the rotors were cleaned with steel wool, 
rinsed with deionized water and acetone, and dried. Just prior to use, the 
rotors were filmed with a dilute stearic acid solution (1000 ppm in 
toluene) and dried. Beakers containing the scaling solutions were placed 
in position to submerge the rotors. The surface of the scaling solution 
was finally covered with mineral oil to prevent evaporation. Rotation of 
the rotors was commenced and the test conducted at about 105.degree. F. 
for 10-16 hours. 
Two separate stock solutions were prepared and mixed to yield the final 
scaling test solution. One solution (Solution A) contained 468 g NaCl, 
121.5 g CaCl.sub.2.sup.. 2H.sub.2 O, and 9722 ml of deionized water. The 
second solution (Solution B) contained 130.05 g of anhydrous Na.sub.2 
SO.sub.4 diluted to one liter with deionized water. Utilizing these 
amounts yielded test solutions which contained 50,000 ppm NaCl and 10,000 
ppm CaSO.sub.4. 
Each beaker in a scaling test contained 440 ml of Solution A, 40 ml of 
Solution B and sufficient inhibitor diluted into 20 ml of deionized water 
to yield the desired test concentration. For example, to obtain a 10 ppm 
inhibitor concentration, 5 ml of 1000 ppm inhibitor stock solution and 15 
ml of deionized water would be added to the test beaker. 
Upon completion of the tests, the rotors were removed from the test 
apparatus, rinsed with acetone, and dried. The scale adhering to the 
rotors was scraped off the rotor surface and then weighed. Percent 
inhibition was determined by comparing the amount of deposition in 
uninhibited solutions (blanks) to the amount in inhibited solutions. A 
standard value of 1.5001 g CaSO.sub.4 was used for the blank. 
EXAMPLES 1-4 
An ethoxylated, propoxylated alkylphenol amine of the claimed formula, 
wherein R is hydrogen, R' is an alkyl group containing 9 carbon atoms, x 
equals 4, z equals 2-3, and a+b equals 4.5, was employed to test the 
corrosion inhibition systems of Examples 1-3. The example 1 system 
contained 7.5 ppm of the amine, whereas Examples 2-3 contained 16 ppm of 
the salt reaction products. Two salts were prepared by reacting the above 
amine in a 1/1 ratio with Westvaco L-5 for Example 2 and glycolic acid for 
Example 3. Example 4 runs were made without corrosion inhibitor for 
comparison purposes. The results are listed below in Table I. 
TABLE I 
______________________________________ 
Corrosion Rate (mils per year) 
16 ppm Inhibitor Continuous Treatment 
Sweet Sour 
Example Oil/brine 
brine Oil/brine 
brine 
______________________________________ 
1 (7.5 ppm) 
3.4 2.0 2.8 2.0 
2 4.72 3.40 4.96 2.40 
3 6.16 16.92 4.72 6.04 
4 (Blank) 12.2 13.6 50.8 55.2 
______________________________________ 
The Example 1 amine alone provided excellent sour corrosion inhibition with 
about 95% protection in each test. Good carbon dioxide inhibition of 85% 
was also provided in a brine environment. 
The Example 2 inhibitor salf prepared with Westvaco L-5 performed 
admirably. Hydrogen sulfide corrosion inhibition (sour) was over 90% for 
an oil/brine environment and over 95% for a brine environment. The Example 
3 inhibitor also gave 90% inhibition in sour environments. 
EXAMPLES 5-17 
Examples 5-17 involved inhibitor systems prepared with two different 
ethoxylated, propoxylated alkylphenol amines. Although these are not the 
claimed alkylphenol amines, it has been discovered that the claimed 
alkylphenol amines have behavior analogous to these compounds tested in 
Examples 5-17, except for the fact that amide derivatives cannot be 
prepared from the ethoxylated compounds claimed herein. The addition of 
the ethoxylation groups attached to the nitrogen makes the invention 
compounds more water soluble. 
Inhibitor A in these examples is an amine having a structure similar to the 
instant formula is that R is an alkyl group having 9 carbon atoms, R' is 
hydrogen, x is about 9.5 and z is about 3, but there are no ethoxylation 
groups on the nitrogen. Inhibitor B in the examples denotes an amine of 
the Inhibitor a formula wherein R is an alkyl group with 9 carbon atoms, 
R' is hydrogen, x is about 4 and z is about 3. 
Examples 5-10 were tested in the sweet environment under two different 
fluid conditions, an oil-brine fluid and a brine fluid composed as 
described above. Each inhibitor was reacted with an acid to produce a salt 
or amide which was then placed in the oil-brine or brine fluid at 
concentrations of 8 ppm and 16 ppm. Percentage reduction in corrosion can 
be calculated by subtracting the results of Table II from the corrosion 
rates without any corrosion inhibiting solution (blank) which are given in 
Example 11, dividing the difference by the blank value and multiplying by 
100. Most examples provided greater than 80% protection in the sweet 
environment. 
TABLE II 
______________________________________ 
Continuous Sweet Tests (mpy) 
Oil-Brine Brine 
Inhibitor 8 ppm 16 ppm 8 ppm 16 ppm 
______________________________________ 
Ex. 5 Westvaco L-5 plus 
4.48 2.64 2.60 2.20 
Inhibitor A in a 1/1 
Acid/Amine Ratio 
Ex. 6 Century D-75 plus 
1.48 0.80 3.48 2.40 
Inhibitor A in a 1/1 
Acid/Amine Ratio 
Ex. 7 Diacid 1550 plus 
1.36 1.00 3.24 2.88 
Inhibitor A in a 1/1 
Acid/Amine Ratio 
Ex. 8 Wayfos M-100 plus 
1.96 1.40 4.00 3.84 
Inhibitor A in a 1/1 
Acid/Amine Ratio 
Ex. 9 Westvaco L-5 plus 
6.68 4.28 2.76 2.92 
Inhibitor A in a 
1/0.75 Acid/Amine 
Ratio 
Ex. 10 
Westvaco L-5 plus 
-- 2.80 -- 2.16 
Inhibitor A in a 1/1 
Acid/Amine Ratio 
Ex. 11 
None 12.2 13.6 
______________________________________ 
Examples 12 and 13 were multiple tests performed on two inhibitor systems 
in a sweet corrosion environment at different inhibitor concentration 
levels. All of these tests were performed in a brine environment which was 
comprised of 100 ml brine and 1 ml of dilute acetic acid. The blank 
corrosion rate without any organic inhibitor was 13.6 mpy. Table III lists 
the results. 
TABLE III 
______________________________________ 
Continuous Sweet Tests In Brine (mpy) 
Inhibitor 3 ppm 7 ppm 16 ppm 
33 ppm 
83 ppm 
______________________________________ 
Ex. 12 
Inhibitor A 
5.44 5.00 3.92 3.28 3.20 
Ex. 13 
Westvaco L-5 
4.80 3.48 3.04 2.64 2.24 
plus Inhibi- 
tor A in a 
1/0.75 ratio 
______________________________________ 
Table III indicates that the salt formed by the reaction of the instant 
amine and the tall oil fatty acid was much more effective in preventing 
corrosion in the sweet environment than the amine alone. At 16 ppm the 
protection level for the salt reached 78%. At higher concentrations of 
inhibitor, much greater protection was obtained. 
EXAMPLES 14-16 
The amines identified as Inhibitor A and Inhibitor B were tested in a sour 
environment for inhibition of hydrogen sulfide corrosion. Table IV below 
lists the results. 
TABLE IV 
______________________________________ 
Continuous Sour Tests (mpy) 
Inhibitor 3 ppm 7 ppm 16 ppm 
33 ppm 
83 ppm 
______________________________________ 
Ex. l4 
Inhibitor A 
4.68 2.64 2.60 2.52 2.48 
Ex. 15 
Inhibitor B 
3.00 2.40 4.20 4.08 2.92 
(holes) 
(holes) 
Ex. 16 
None 55.2 mpy 
______________________________________ 
Excellent results were achieved in hydrogen sulfide corrosion control with 
the use of Inhibitors A and B. Once the concentration of the inhibitor was 
raised to 7 ppm or better, hydrogen sulfide corrosion was almost completely 
eliminated. Corrosion protection rates were 95% or better for almost every 
concentration greater than 7 ppm for both Inhibitors A and B. At the 
remarkably low and cost efficient concentration of 7 ppm, 95.2% protection 
was achieved with Inhibitor A and 95.7% protection was achieved with 
Inhibitor B. Problems existed with the tests at 16 ppm and 33 ppm for 
Inhibitor B. Holes and high corrosion rates were observed in the coupons. 
It is believed that air probably contaminated these two test bottles and 
ruined the tests. 
EXAMPLE 17 
Wayfos M-100, a trademarked phosphate ester with a nonylphenol group having 
10 ethylene oxides groups sold by Phillip A. Hunt Chemical Corp., was 
reacted with Inhibitor a to produce a salt compound that was quite 
effective in calcium sulfate scale control The scaling test described at 
the beginning of the examples was followed in the laboratory to produce 
the results of Table V at different concentrations. 
TABLE V 
______________________________________ 
CaSO.sub.4 Scaling Tests (% Inhibition) 
1 ppm 2 ppm 3 ppm 5 ppm 7 ppm 8 ppm 13 ppm 
______________________________________ 
Ex. 0% 0% 27.5% 49.9% 64.3% 82.2% 92% 
17 
______________________________________ 
The combination of Inhibitor A and the organic phosphate produce superior 
calcium sulfate scale control at low concentrations. Ninety-two percent 
protection against calcium sulfate scale was achieved at only 13 ppm 
concentration of inhibitor. Although the compound was only tested for 
calcium sulfate scale inhibition, it is believed to be also effective 
against calcium carbonate scale. Compounds that are this effective against 
calcium sulfate scale are almost always effective in carbonate scale 
control. 
Other variations and modifications may be made in the concepts described 
above by those skilled in the art without departing from the concepts of 
the present invention. Accordingly, it should be clearly understood that 
the concepts disclosed in the description are illustrative only and are 
not intended as limitations on the scope of the invention.