MOPA (Methoxypropylamine)

MOPA (Methoxypropylamine)

MOPA (Methoxypropylamine)

Description: 3-Methoxypropylamine (MOPA) is a colorless to yellow liquid with an aminelike odor. It is miscible in water.

Synonyms: 3-Aminopropyl methyl ether, 3-Methoxy-1-propanamine, 1-Amino-3-methoxypropane, 3-Methoxy-n-propylaminl

Applications: Intermediate used in the production of: Corrosion inhibitor and Dyestuff

Methoxypropylamine is a clear colourless chemical in liquid form with an ammonia-like odour. It is completely miscible in water and common organic solvents. Methoxypropylamine is used in the manufacture of amine soaps, which are used to make synthetic and natural resins and wax dispersions and emulsions. These products are used in water-based paints and floor and fabric finishes. Methoxypropylamine also finds application as a corrosion inhibitor. It is used for preparing waxes which are not sensitive to water, since it displays volatility in the presence of water and leaves behind an insoluble wax film. It is also used as an intermediate for chemicals used to treat water and floor waxes. Methoxypropylamine reacts with acrylonitrile polymers to produce polyelectrolytes, which are soluble in water and hence, find applications as flocculating agents.

These multiple applications and favourable reaction characteristics of methoxypropylamine make the study of the global methoxypropylamine market an important read.

EC / List no.: 226-241-3
CAS no.: 5332-73-0
Mol. formula: C4H11NO

For more than a decade, multiple component boiler water treatment programs based on “polyamine” chemistry have been applied commercially in the global boiler water treatment marketplace. These programs have been used in both high and low-pressure systems. 1-11 Although there is a considerable body of literature that reports on the results obtained from the application of polyamine programs in operating boilers, there is a lack of detailed research comparisons between a “traditional” boiler water treatment program and a polyamine program. A traditional boiler treatment program for the purpose of this discussion would include a dissolved oxygen scavenger appropriate to the operating pressure of the boiler to protect the system against dissolved oxygen corrosion. Examples of oxygen scavengers employed for boiler corrosion protection would include sodium sulfite, hydrazine and various hydroxylamines, such as diethylhydroxylamine (DEHA), hydroquinone, ascorbic/erythorbic acid and carbohydrazide, among others. A traditional treatment would also include a neutralizing amine component or a blend of such amines for pH elevation of the boiler feedwater and condensate. Common examples used in traditional boiler water treatment would include amines such as cyclohexylamine, morpholine, diethylaminoethanol (DEAE), methoxypropylamine (MOPA) and monoethanolamine (MEA), among others. The polyamine program, in contrast, does not employ a traditional dissolved oxygen scavenger, but rather a long-chain fatty diamine corrosion inhibitor that is combined with a traditional blend of neutralizing amines for pH elevation in a similar manner to the traditional approach described above. Polymeric dispersant may be added to either the traditional or polyamine program for internal boiler deposit control. The pH control ranges targeted in the boiler feedwater and condensate would be identical for the traditional and polyamine programs, thus the difference in the polyamine program is the presence of the polyamine corrosion inhibitor and the absence of traditional dissolved oxygen scavenger. For more than a decade, multiple component boiler water treatment programs based on “polyamine” chemistry have been applied commercially in the global boiler water treatment marketplace. These programs have been used in both high and low-pressure systems. 1-11 Although there is a considerable body of literature that reports on the results obtained from the application of polyamine programs in operating boilers, there is a lack of detailed research comparisons between a “traditional” boiler water treatment program and a polyamine program. A traditional boiler treatment program for the purpose of this discussion would include a dissolved oxygen scavenger appropriate to the operating pressure of the boiler to protect the system against dissolved oxygen corrosion. Examples of oxygen scavengers employed for boiler corrosion protection would include sodium sulfite, hydrazine and various hydroxylamines, such as diethylhydroxylamine (DEHA), hydroquinone, ascorbic/erythorbic acid and carbohydrazide, among others.
A traditional treatment would also include a neutralizing amine component or a blend of such amines for pH elevation of the boiler feedwater and condensate.
Common examples used in traditional boiler water treatment would include amines such as cyclohexylamine, morpholine, diethylaminoethanol (DEAE), methoxypropylamine (MOPA) and monoethanolamine (MEA), among others. The polyamine program, in contrast, does not employ a traditional dissolved oxygen scavenger, but rather a long-chain fatty diamine corrosion inhibitor that is combined with a traditional blend of neutralizing amines for pH elevation in a similar manner to the traditional approach described above. Polymeric dispersant may be added to either the traditional or polyamine program for internal boiler deposit control. The pH control ranges targeted in the boiler feedwater and condensate would be identical for the traditional and polyamine programs, thus the difference in the polyamine program is the presence of the polyamine corrosion inhibitor and the absence of traditional dissolved oxygen scavenger.

Methoxypropylamine is a neutralizing amine used in the water treatment industry.

Methoxypropylamine is a Film-Forming Amine in Steam/Water Cycles which influences corrosion and deposition processes

3-Methoxy Propyl Amine (MOPA)
CAS: 5332-73-0
METHOXYPROPYLAMINE (MOPA)
CAS#: 5332-73-0
Synonyms: 3-Methoxy-1-Propaneamine, 3-Methoxy Propyl Amine
Molecular Weight: 89.1 gm/mole

Methoxypropylamine (MOPA) is a clear, colorless liquid. It typically and an ammonia like odor.
It has properties typical of primary amines and is miscible with water, ethanol, toluene, acetone, hexane and other standard solvents.
Methoxypropylamine  can be used in making amine soaps that can be used in dispersions and emulsions of natural and synthetic waxs used in flowing, textiles, water-based paints etc. Methoxypropylamine  volatilizes with water and leaves behind an insoluble wax film. Further, methoxypropylamine in dilute solutions does not have an objectionable odor.

Methoxypropylamine can be used in the following applications:
Emulsifier in anionic coatings and wax formulations
Methoxypropylamine is commonly used in water treatment applications as a flocculating agent, and it is can be used to inhibit corrosion in steam condensate systems. It can also reduce presence of carbon dioxide in water.
Morpholine substitute
Insecticide emulsions
Dye solvents, textile assistants
Adhesion promoter for aluminum and aluminum alloy surface coatings
When reacted with bis(2-carbamoylphenyl) disulfides it can be used to help control mildew fungi in latex and alkyd paints
Methoxypropylamine is used in the manufacture of polyamide resins
It is used as a corrosion prevention additive in oil drilling equipment etc

1-Propanamine, 3-methoxy-
Other
IUPAC names
3-methoxypropan-1-amine
MOPA
3-Methoxypropylamine
MOPA
3-methoxypropylamine
MOPA
3-Methoxypropylamine (MOPA)

Methoxypropylamine

Methoxypropylamine
MOPA
MOPA
MOPA
Trade names
.gamma.-Methoxypropylamine
MOPA
1-Amino-3-methoxypropane
MOPA
1-Propanamine, 3-methoxy- (9CI)
MOPA
3-Aminopropyl methyl ether
MOPA
3-Methoxy-1-propanamine
MOPA
3-Methoxy-n-propylamine
MOPA
3-Methoxypropylamin
MOPA
3-Methoxypropylamine
MOPA
Propanolamine methyl ether
MOPA
Propylamine, 3-methoxy- (6CI, 7CI, 8CI)

Methoxypropylamine finds abundant use in insecticide emulsions, textiles, and dye solvents. The chemical is utilized in places where mild volatility is required. In the process of manufacturing of dyes, it is also utilized in the modification of polybutadiene-based isocyanates. In its diluted form, the chemical is utilized in the treatment of aluminum surfaces and aluminum, which assists in enhancing the adhesive capacity of various types of coating that could be utilized on various aluminum surfaces.

Methoxypropylamine reacts with 2-carbamoylphenyl disulfides to make substances that are utilized in the restricting the growth of the mildew fungi in latex paints and alkyd.
Methoxypropylamine comes with several specialized uses, which is likely to play an important role in the growth of the global methoxypropylamine (MOPA) market

Methoxypropylamine (MOPA) Market: Key Trends, Drivers

It has been observed that in dilute solution forms, methoxypropylamine does not emanate any foul odour, and hence is a suitable replacement for morpholine. This replacement characteristic is expected to drive the market growth of methoxypropylamine.

Methoxypropylamine also finds applications in dye solvents, textiles and insecticide emulsions. It should be mentioned that methoxypropylamine is used where mild volatility is preferred. It is also used to modify polybutadiene-based isocyanates in the manufacture of dyes. Methoxypropylamine, in its dilute form, is used to treat aluminium and aluminium surfaces. This is done in order to enhance the adhesive capability of different coating types, which could be applied to aluminium surfaces.

It is noteworthy that methoxypropylamine reacts with bis (2-carbamoylphenyl) disulfides to produce substances which are used in limiting the growth of mildew fungi in alkyd and latex paints. Methoxypropylamine also reacts with carbamates, quinones, benzothiazole and other substrates to obtain similar products. It can react with styrene-maleic anhydride copolymer and a diamine to produce compounds which could prove to be effective against silicosis. Such specialised applications have been propelling growth for the global methoxypropylamine market.

Plant growth regulators and phenol-free paint removers can be produced from methoxypropylamine, and hence, their demand has been driving the market. Also, it has been observed that methoxypropylamine is used to manufacture a fluorescent brightener for cellulosic textiles, and that the brightener showed high effectiveness at low temperatures and did not cause discolouration of washing powders; thereby making methoxypropylamine a preferred raw material in the manufacture of brighteners.

Methoxypropylamine is also used to prevent corrosion in steam condensate systems. The addition of methoxypropylamine in these systems is shown to hinder the corrosion process, which occurs due the presence of carbon dioxide in water. Methoxypropylamine finds application as an additive to restrict the process of corrosion in oil refining equipment since crude oil can contain acidic materials, which in turn may corrode the equipment. Growth of the crude oil industry, hence, is expected to indirectly boost the demand for methoxypropylamine in the next few years.

However, methoxypropylamine is found to be flammable, and is also known to cause skin irritation and burning in case of skin contact. It could also prove to be harmful in case of accidental ingestion. These factors may prove to be detrimental to the market growth of methoxypropylamine.

High frequency of exposure to high concentrations of methoxypropylamine can cause respiratory problems and temporary vision distortion. Specific locations, where occurrence of methoxypropylamine leaks could potentially take place need to be properly ventilated. The U.S. regulatory body OSHA (Occupational Safety and Health Administration) has mentioned specific regulations to be followed while handling and storing methoxypropylamine and for protecting oneself from methoxypropylamine. Such stringent regulations, in turn, could also dampen the market growth of methoxypropylamine in the near future.

Other names: Propylamine, 3-methoxy-; γ-Methoxypropylamine; 1-Amino-3-methoxypropane; 3-Aminopropyl methyl ether; 3-Methoxy-n-propylamine; 3-Methoxy-1-propanamine; 3-Methoxypropylamine; 3-Methyoxypropylamine; 3-Methoxy-1-propylamine; 3-MPA; 1-Methoxy-3-aminopropane; NSC 552; Propanolamine methyl ether

3-Methoxypropylamine (MOPA) is colorless transparent liquid. This chemical is soluble in water and alcohols, ethers, acetone etc.

3-Methoxypropylamine is mainly used in the manufacture of disperse blue 60 and other dyes. 3 methoxy propyl amine could also be used in pharmaceutical intermediates, the anticorrosion of petroleum, detergent

Methoxypropylamine refers to a clear, colorless chemical that is found in the form of a liquid with an odor resembling ammonia.
Methoxypropylamine  is totally miscible in common organic solvents and water.
Methoxypropylamine is utilized in the making of amine soaps, which are utilized in the making of natural and synthetic resins, emulsions, and wax dispersions.
These products find abundant use in floor and fabric finishes and water-based paints.
Flourishing paints industry is likely to play an important role in the expansion of the global methoxypropylamine (MOPA) market

Methoxypropylamine also finds use as corrosion inhibitor.
Methoxypropylamine is utilized in the preparation of waxes that are not sensitive to water and thus exhibit volatility in the presence of water and leaves behind an insoluble film of wax.
Methoxypropylamine also finds use as chemicals for the treatment of floor waxes and water.
Once methoxypropylamine gets into reaction with acrylonitrile polymers for the production of polyelectrolytes that are soluble in water and thus finds use as flocculating agent.
All these uses of the product is expected to bolster growth of the global methoxypropylamine (MOPA) market in the years to come.

Market Size Split by Application:
Dyes (Disperse Blue 60)
Pharmaceutical Intermediates
Corrosion Inhibitor
Others

Name: 3-Methoxypropylamine
Synonyms: 1-Amino-3-methoxypropane; 3-Methoxy-1-aminopropane; 3-Methoxypropyl-1-amine

3-Methoxypropylamine is a liquid C3-Aminoether. 3-Methoxypropylamine (MOPA) is used mainly as a corrosion inhibitor.

Chemical Properties
CLEAR COLOURLESS TO FAINTLY COLORED LIQUID

Uses
Organic intermediate, emulsifier in anionic coatings and wax formulations.

Hazard
Flammable, moderate fire risk. Toxic by ingestion and inhalation.

Safety Profile
Poison by intravenous route. Irritating to skin, eyes, and mucous membranes. Dangerous fire hazard when exposed to heat or flame; can react with oxidizing materials. To fight fire, use CO2, dry chemical. When heated to decomposition it emits toxic fumes of NOx. See also AMINES.
3-Methoxypropylamine Preparation Products And Raw

On the basis of application type, the global methoxypropylamine market is segmented as follows:

Corrosion inhibition
Dyestuffs
Anti-scaling agents
Agrochemical uses
Functional fluids (closed systems)
Functional fluids (open systems)
Intermediates
Processing aids
Water treatment
Power generation

3-methoxypropylamine (methoxypropylamine) is a clear, colorless liquid with an ammonia-like odor. This chemical is totally miscible in organic solvents and water. The application of this compound is as flocculants in water treatment systems and also as a solvent in the dye and textile industries.

3-methoxypropylamine APPLICATIONS
3-methoxypropylamine is used in the production of amine soaps and fatty acids and some natural resins and products that are used in paint and other industries.
In making waxes that are insensitive to water MOPA is used and because of its volatility characterization it volatile with water.
Moreover, this material does not have a recognizable odor in solutions and in comparison with morphine it might be an awesome substitute.
In applications which the volatility of component is important 3-Methoxypropylamine finds its way like dye solvents, textile, and emulsions
In the synthesis of polyamide resins and dyes
Because 3-Methoxypropylamine improves the adhesion properties of coatings so that it is used in aluminum and aluminum alloy surfaces treatment because.
By the reaction of 3-Methoxypropylamine and sodium hydroxide, a new useful material for paint removal is obtained. ( phenol-free paint removers)
In the production of brighteners for cellulosic textile materials
In washing powders and to improve their function in low temperatures
By reacting this material and some polymers like acrylonitrile water-soluble flocculants will obtain
As a corrosion inhibitor – the corrosion that is result of the presence of carbon dioxide may reduce by adding this chemical
On the other hand, in oil refining equipment’s adding Methoxypropylamine has been reported to prevent corrosion due to the equipment’s acidic media

Toxicity of 3-Methoxypropylamine
For workers who are at the risk of exposure of 3-Methoxypropylamine well-ventilated areas must be designed and they must use goggles with face shields, special suits, and rubber boots. Repeated exposure of workers to the vapors could cause eye irritation. The oral dosage for methoxypropylamine is 0.69 g/kg and it is, therefore, and in case of swallowed it grouped as relatively toxic . for Skin, the dermal LD50 dosage for rabies is >3.0 g/kg that present slight toxicity in case of skin contact.

Regulatory process names
3-methoxypropylamine
EC Inventory, REACH pre-registration, Other
Translated names
CAS names
1-Propanamine, 3-methoxy-

IUPAC names
3-methoxypropan-1-amine
3-Methoxypropylamine (MOPA)
Methoxypropylamine
MOPA

Trade names
.gamma.-Methoxypropylamine
1-Amino-3-methoxypropane
1-Propanamine, 3-methoxy- (9CI)
3-Aminopropyl methyl ether
3-Methoxy-1-propanamine
3-Methoxy-n-propylamine
3-Methoxypropylamin
Propanolamine methyl ether
Propylamine, 3-methoxy- (6CI, 7CI, 8CI)

3-Methoxypropylamine
5332-73-0
3-methoxypropan-1-amine
1-Propanamine, 3-methoxy-
1-Amino-3-methoxypropane
3-Aminopropyl methyl ether
3-Methyoxypropylamine
3-Methoxy-n-propylamine
3-Methoxy-1-propanamine
Propylamine, 3-methoxy-
3-MOPA
Propanolamine methyl ether
gamma-Methoxypropylamine
NSC 552
1-methoxy-3-aminopropane
UNII-VT819VO82Z
CCRIS 6178
3-methoxy-propylamine
3-Methoxy-1-propylamine
EINECS 226-241-3
.gamma.-Methoxypropylamine
BRN 0878144
AI3-25438
VT819VO82Z
DSSTox_CID_7596
DSSTox_RID_78522
DSSTox_GSID_27596
3-Methoxypropylamine, 99+%
3-methoxypropyl amine
3-methoxy-1-aminopropane
CAS-5332-73-0
[3-(methyloxy)propyl]amine
3-(methyloxy)-1-propanamine
methoxypropylamine
3-methoxyproylamine
3-metoxypropylamine
3-Methoxypropylamin
methoxy propyl amine
MFCD00014831
3-methoxylpropylamine
3-methoxy propylamine
(3-methoxypropyl)amine
3-methoxy propyl amine
PubChem16804
3-methoxy-n-propyl-amine
3-Methoxypropane-1-amine
ACMC-1B1QS
EC 226-241-3
3-Methoxypropylamine, 99%
KSC497S7T
WLN: Z3O1
NSC552
CHEMBL3186458
DTXSID7027596
CTK3J7979
NSC-552
PROPANE,1-AMINO,3-METHOXY

MOPA is Methoxypropylamine which is a clear, colorless liquid with an ammoniacal odor.

CAS#: 5332-73-0
Functions: Primary amine
Product Applications: Alkalinity control, Corrosion inhibitor
Product Classes: Amine, Lubricants, Metalworking & Grease, Primary

Methoxypropylamine is a clear colourless chemical in liquid form with an ammonia-like odour. It is completely miscible in water and common organic solvents. Methoxypropylamine is used in the manufacture of amine soaps, which are used to make synthetic and natural resins and wax dispersions and emulsions. These products are used in water-based paints and floor and fabric finishes. Methoxypropylamine also finds application as a corrosion inhibitor. It is used for preparing waxes which are not sensitive to water, since it displays volatility in the presence of water and leaves behind an insoluble wax film. It is also used as an intermediate for chemicals used to treat water and floor waxes. Methoxypropylamine reacts with acrylonitrile polymers to produce polyelectrolytes, which are soluble in water and hence, find applications as flocculating agents.

These multiple applications and favourable reaction characteristics of methoxypropylamine make the study of the global methoxypropylamine market an important read.

ChemSpider 2D Image | 3-Methoxypropylamine | C4H11NOSave3DZoom
3-Methoxypropylamine
Molecular FormulaC4H11NO
Average mass89.136 Da
Monoisotopic mass89.084061 Da
ChemSpider ID1609

Names and SynonymsDatabase ID(s)
Validated by Experts, Validated by Users, Non-Validated, Removed by Users
1-Amino-3-methoxypropane
1-Propanamine, 3-methoxy- [ACD/Index Name]
226-241-3 [EINECS]
3-Methoxy-1-propanamin [German] [ACD/IUPAC Name]
3-Methoxy-1-propanamine [ACD/IUPAC Name]
3-Méthoxy-1-propanamine [French] [ACD/IUPAC Name]
3-methoxypropan-1-amin [German]
3-Methoxypropan-1-Amine
3-Methoxypropylamine
5332-73-0 [RN]
γ-Methoxypropylamine
(3-methoxypropyl)amine
[5332-73-0]
1-methoxy-1-propanamine [ACD/IUPAC Name]
1-Methoxy-3-aminopropane
3 -Methoxypropylamine
3-​methoxypropylamine
3-AMINOPROPYL METHYL ETHER
3-Methoxy-1-propylamine
3-Methoxy-n-propylamine
3-Methoxy-propylamine
3-Methyoxypropylamine
3-MOPA
MOPA
PROPANE,1-AMINO,3-METHOXY
Propanolamine methyl ether
Propylamine, 3-methoxy-
STR00952
WLN: Z3O1
γ-Methoxy propyl amine
γ-methoxypropylamine
γ-Methoxypropylamine

Thermal Decomposition of 3-Methoxypropylamine as an Alternative Amine in PWR Secondary Systems
Masafumi DOMAE  and Kazutoshi FUJIWARA Central Research Institute of Electric Power Industry,
2-6-1 Nagasaka, Yokosuka, Kanagawa 240-0196, Japan (Received July 1, 2008 and accepted in revised form October 12, 2008)

The secondary coolant of pressurized water reactors is buffered to slightly alkaline pH by ammonia or amines in order to suppress corrosion.
3-Methoxypropylamine (MOPA) is one of the promising alternative amines.
The thermal decomposition of MOPA was studied under two conditions:
(i) a dissolved oxygen (DO) concentration of less than 5 ppb at 280C for 1.5 h and
(ii) a DO concentration of 20 ppb at 70C for 2 h.

The initial MOPA concentration was 10 ppm.
After the tests, concentrations of MOPA and carboxylic acids were measured.
Approximately 9 to 15% of MOPA was decomposed after the tests.
Carboxylic acid concentrations were as follows:
(i) formate 110 ppb, acetate 260 ppb and propionate 400 ppb at 280C, and
(ii) formate less than 2 ppb, acetate 60 ppb and propionate 1270 ppb at 70C.

The reaction mechanism of MOPA decomposition was estimated from the present experimental results.
At 280C, the hydrolysis of the ether bond initiates the decomposition, and the subsequent bond cleavage of C-N and/or C-C occurs.
At 70C, hydrogen abstraction by an oxygen molecule is the initiation reaction. MOPA radicals and HO2 or C1 compounds propagate a chain reaction and result in a relatively high yield of propionate. KEYWORDS: 3-methoxypropylamine, thermal decomposition, carboxylic acid, dissolved oxygen, temperature, pressurized water reactor, secondary systems

In secondary systems of pressurized water reactors (PWRs), reduction in iron concentration in feedwater is one of the most important subjects.
Iron oxides are carried into stream generators (SGs) and deposited on SG tubing.
Then, the degradation of heat exchange efficiency, the reduction in the cross-sectional area of secondary coolant flow and the oscillation of water level, and so on may occur.
Iron is generated through the corrosion of piping.
It is considered that a reducing and slightly alkaline condition prevents the corrosion of the piping.
In most PWR plants, secondary water chemistry is controlled by hydrazine as an oxygen scavenger and a weak base.
In Japan, the pH of the secondary coolant has been adjusted by the addition of ammonia.
However, ammonia is volatile and tends to transfer to a gas phase during boiling.
As a result, it is difficult to control the pH of the secondary coolant by ammonia addition in a sufficiently alkaline region under two-phase flow conditions.
To overcome this phenomenon, ammonia concentration should be increased or ammonia should be substituted by a less volatile base.
Higher concentration ammonia is effective for suppressing corrosion, but concern about the dissolution of copper ions may arise.
Copper-containing materials should be removed before increaseing the ammonia concentration.
As alternative amines, 2-ethanolamine has recently been used in Japan,and in overseas, several amines have been used.

Some candidate amines are listed in Ref.
Among the amines, 3-methoxypropylamine (MOPA) is promising.
It is a slightly strong base, and a lower concentration is required to adjust a constant pH.
Its volatility is moderate, and it is expected that MOPA can adjust pH with tolerance even under boiling conditions without concentration in a local area, such as a crevice.
In the US, MOPA has been added to secondary systems of commercial PWR plants.
In order to evaluate the applicability of MOPA as a pH modifier in PWR secondary systems, many test results must be accumulated: the thermal decomposition behavior of MOPA, the coMOPAtibility of MOPA with materials in secondary systems, the distribution of MOPA and pH in secondary circuits, the integrity of turbine materials in the presence of MOPA, the integrity of SG tubing in the presence of MOPA, the effect on the scale deposition behavior, and so on.
In the present paper, the thermal decomposition of MOPA was examined.
In particular, the production of carboxylic acid was considered from the aspect of material issues.
In the previous work, only decomposition rate of MOPA was reported.
Concentrations of the carboxylic acids were measured after thermal decomposition tests of MOPA in an autoclave, and the reaction mechanism of the MOPA decomposition was discussed

Methoxypropylamine and hydrazine steam condensate corrosion inhibitor compositions and methods
Abstract
Use of methoxypropylamine as a neutralizing amine in combination with hydrazine to prevent corrosion in steam condensate systems or in other low solids aqueous systems.
US4192844A
United States

3-Methoxypropylamine (MPA) is one of the promising alternative amines to control pH value of the secondary coolant of pressurized water reactors.
Several carboxylic acids may be generated through thermal decomposition of the amine, and possibly brings about acidic environment for turbines.
Therefore, it is important to evaluate yields of the carboxylic acids resulted from the thermal decomposition of the amine.
The thermal decomposition of MPA was investigated under two conditions: (1) dissolved oxygen (DO) concentration less than 5 ppb at 553 K and (2) DO concentration of 20 ppb at 343 K.
Initial MPA concentration was 10 ppm.
After the tests, concentrations of MAP and carboxylic acids were measured with ion chromatography.
Approximately 9 to 15% of MPA was decomposed after the tests.
Carboxylic acid concentrations were as follows: (1) formate 110 ppb, acetate 260 ppb and propionate 400 ppb at 553 K, (2) formate less than 2 ppb, acetate 60 ppb and propionate 1270 ppb at 343 K.
Reaction mechanism of the MPA decomposition was estimated based on the present experimental results. (author)

For more than a decade, multiple component boiler water treatment programs based on “polyamine” chemistry have been applied commercially in the global boiler water treatment marketplace.
These programs have been used in both high and low-pressure systems.
Although there is a considerable body of literature that reports on the results obtained from the application of polyamine programs in operating boilers, there is a lack of detailed research comparisons between a “traditional” boiler water treatment program and a polyamine program.
A traditional boiler treatment program for the purpose of this discussion would include a dissolved oxygen scavenger appropriate to the operating pressure of the boiler to protect the system against dissolved oxygen corrosion. Examples of oxygen scavengers employed for boiler corrosion protection would include sodium sulfite, hydrazine and various hydroxylamines, such as diethylhydroxylamine (DEHA), hydroquinone, ascorbic/erythorbic acid and carbohydrazide, among others.
A traditional treatment would also include a neutralizing amine component or a blend of such amines for pH elevation of the boiler feedwater and condensate.
Common examples used in traditional boiler water treatment would include amines such as cyclohexylamine, morpholine, diethylaminoethanol (DEAE), methoxypropylamine (MOPA) and monoethanolamine (MEA), among others.
The polyamine program, in contrast, does not employ a traditional dissolved oxygen scavenger, but rather a long-chain fatty diamine corrosion inhibitor that is combined with a traditional blend of neutralizing amines for pH elevation in a similar manner to the traditional approach described above.
Polymeric dispersant may be added to either the traditional or polyamine program for internal boiler deposit control.
The pH control ranges targeted in the boiler feedwater and condensate would be identical for the traditional and polyamine programs, thus the difference in the polyamine program is the presence of the polyamine corrosion inhibitor and the absence of traditional dissolved oxygen scavenger.

There are several different neutralizing amine components typically used in the treatment of boiler feedwater and/or condensate.
Neutralizing amines each have different chemical properties, and it is important to understand the differences so that the correct components can be applied.
Neutralizing amines typically applied in power plant systems are cyclohexylamine (CHA), methoxypropylamine (MPA), monoethanolamine (ETA), and morpholine.

Neutralizing amines are weak bases that are typically classified in terms of their “neutralizing capacity,” “basicity,” and “distribution ratio.”
The neutralizing capacity is a measure of how much amine it takes to neutralize a given amount of acid.
Usually it is expressed as the ppm of CO2 (or carbonic acid) neutralized per ppm of neutralizing amine.
Once the acid has been neutralized, each amine has a different ability to boost pH, which is accomplished by the hydrolysis of the amine to form hydroxyl (OH-) ions.

Distribution ratio refers to the volatility of the amine, which is one factor that helps determine how each amine component will partition between the liquid and steam phases.
The distribution ratio of a particular amine also influences how much amine is recycled throughout the system, and how much amine will be lost from the system via boiler blowdown and steam venting.

While neutralizing amine chemistry may appear to be relatively straightforward, it is in fact quite complex.
For example, the distribution ratio for a given amine is actually a function of pressure, temperature and pH.
This means if you feed more or less neutralizing amine in a given system and affect the pH, the distribution of the amine between the liquid and steam phases will change as well.

In addition, the chemistry of neutralization is actually based on equilibrium chemistry of weak acids and weak bases.
In many cases, there are multiple neutralizing amine components and acid components present so it becomes even more difficult to predict the amine distribution and pH profile across the system without using sophisticated computerized modeling techniques or without performing extensive empirical in-plant analyses.

The thermal stability of the neutralizing amine must also be considered when designing a treatment program to control FAC.
Most amines degrade to some degree in an aqueous, alkaline, high temperature environment to form carbon dioxide, organic acids and ammonia.
Morpholine, CHA, ETA, and MPA are considered the most thermally stable amines and are routinely employed in high-pressure power plant applications.

Practically all steam generators in power plants use some type of neutralizing amines or a blend of neutralizing and filming amines to prevent corrosion in the secondary water system.
Neutralizing amines such as cyclohexylamine, methoxypropylamine, ethylamine, ethanolamine, morpholine, and dimethylaminoethanol, work by controlling pH (normally in the range 9.2 < pHRT < 10) and thus minimizing the source term of corrosion release.
Film forming amines, on the other hand, form a continuous layer between the metal and the coolant, thus preventing the attack of corrosive agents.
When they attach to the corroded metal surface, they modify it, reducing the apparent corrosion rate.
It has been observed that corrosion inhibitors adsorb better on iron-based materials in the active state than in the passive state.
The adsorption behavior on iron oxides is not very sensitive to the chemical structure of the adsorbing molecule, but is due to the nature of the surface and chemical effects of the oxidized surface.
At high temperatures the decomposition of organic amines can induce the formation of amine compounds and or nitrile functional derivatives

It has been observed that in dilute solution forms, methoxypropylamine does not emanate any foul odour, and hence is a suitable replacement for morpholine. This replacement characteristic is expected to drive the market growth of methoxypropylamine.

Methoxypropylamine also finds applications in dye solvents, textiles and insecticide emulsions. It should be mentioned that methoxypropylamine is used where mild volatility is preferred. It is also used to modify polybutadiene-based isocyanates in the manufacture of dyes. Methoxypropylamine, in its dilute form, is used to treat aluminium and aluminium surfaces. This is done in order to enhance the adhesive capability of different coating types, which could be applied to aluminium surfaces.

It is noteworthy that methoxypropylamine reacts with bis (2-carbamoylphenyl) disulfides to produce substances which are used in limiting the growth of mildew fungi in alkyd and latex paints. Methoxypropylamine also reacts with carbamates, quinones, benzothiazole and other substrates to obtain similar products. It can react with styrene-maleic anhydride copolymer and a diamine to produce compounds which could prove to be effective against silicosis. Such specialised applications have been propelling growth for the global methoxypropylamine market.

Plant growth regulators and phenol-free paint removers can be produced from methoxypropylamine, and hence, their demand has been driving the market. Also, it has been observed that methoxypropylamine is used to manufacture a fluorescent brightener for cellulosic textiles, and that the brightener showed high effectiveness at low temperatures and did not cause discolouration of washing powders; thereby making methoxypropylamine a preferred raw material in the manufacture of brighteners.

Methoxypropylamine is also used to prevent corrosion in steam condensate systems. The addition of methoxypropylamine in these systems is shown to hinder the corrosion process, which occurs due the presence of carbon dioxide in water. Methoxypropylamine finds application as an additive to restrict the process of corrosion in oil refining equipment since crude oil can contain acidic materials, which in turn may corrode the equipment. Growth of the crude oil industry, hence, is expected to indirectly boost the demand for methoxypropylamine in the next few years.

However, methoxypropylamine is found to be flammable, and is also known to cause skin irritation and burning in case of skin contact. It could also prove to be harmful in case of accidental ingestion. These factors may prove to be detrimental to the market growth of methoxypropylamine.

High frequency of exposure to high concentrations of methoxypropylamine can cause respiratory problems and temporary vision distortion. Specific locations, where occurrence of methoxypropylamine leaks could potentially take place need to be properly ventilated. The U.S. regulatory body OSHA (Occupational Safety and Health Administration) has mentioned specific regulations to be followed while handling and storing methoxypropylamine and for protecting oneself from methoxypropylamine. Such stringent regulations, in turn, could also dampen the market growth of methoxypropylamine in the near future.

Corrosion control method using methoxypropylamine (MOPA) in water-free petroleum and petrochemical process units
Abstract
A method of inhibiting corrosion in separation units of waterfree petroleum and petrochemical hydrocarbon processing systems which comprises adding a compound corresponding to formula I below either alone or in combination with a film-forming amine corrosion inhibitor to the hydrocarbon being processed: formula I r-o-(Ch2)nnh2, wherein N is 2 or 3 and R is a lower alkyl radical of not more than 4 carbon atoms.
Inventors:
Maynard, T C; White, J A
Publication Date:
1980-10-21
OSTI Identifier:
6581065
Illustrative of compounds falling within composition 1 are methoxypropylamine (MOPA), ethoxypropylamine, methoxyethylamine and the like. The most preferred compound is MOPA. To simplify further discussions herein of the invention, it will be illustrated by using MOPA although it is understood that the other compounds falling within Formula I are also operative.
A very important aspect of the present invention is the discovery that MOPA will control or prevent corrosion without forming significant or troublesome deposits over either short or prolonged periods of time. In contrast to MOPA, other presently known corrosion inhibitors tested in water-free systems cause significant deposit formation. MOPA is thus far superior to the known corrosion inhibitors.
The explanation for this outstanding characteristic of MOPA may lie in the apparent ability to MOPA to form liquid hydrochloride salts under dry conditions at ambient temperature. Although the salts may separate from the hydrocarbon stream, they do not form significant solid deposits.
MOPA can be added to the separation unit at any convenient point after the hydrocarbon leaves the reactor portion of the system for treatment in the separation unit. A convenient point of addition would be just before the hydrocarbon passes through the distillation column. The inhibitor can also be pumped directly into the gaseous overhead line. The particular point at which MOPA is added will depend largely on the design of the particular equipment and the point where greatest corrosion problems are manifested.
The dosage level of MOPA will depend on system parameters as well as the nature of the hydrocarbon. Corrosion inhibiting amounts will have to be determined on a case by case basis. Generally, the dosages will lie in the range of 5-500 ppm. Since the corrosion is caused by the acid content of the hydrocarbon, a useful dosage approach may be to adjust the pH of the first condensate. In this case, the pH should be adjusted to above pH 4.0 and preferably above pH 5.0. Unlike systems utilizing ammonia as a corrosion inhibitor, it is not essential that the pH be maintained below a given point–upper limits depend largely upon economic considerations.
As noted earlier, MOPA may readily be used to control corrosion in conjunction with film-forming corrosion inhibitors. Such film-forming inhibitors operate most economically at a pH above 4.5. Since MOPA is particularly effective in increasing the pH of the initial condensate, the amount of film former that is required is thus substantially lessened.
Among the film-forming corrosion inhibitors which can be used in conjunction with MOPA to provide an overall system of protection are compounds formed by reacting certain aliphatic monoamines with polymerized fatty acids under salt-forming conditions.
The aliphatic monoamines used in preparing film-forming inhibitors are those amines having the general structural formula: ##STR1## where R is an aliphatic hydrocarbon radical of 8 to 22 carbon atoms in chain length and both R2 and R3 are selected from the group consisting of hydrogen and an aliphatic hydrocarbon radical of 1 to 22 carbon atoms in chain length.
The above structural formula includes both primary and secondary aliphatic monoamines as well as the tertiary aliphatic monoamines. Illustrative compounds coming within the above general formula include such primary amines as n-dodecyl amine, n-tetradecyl amine, n-hexadecylamine, lauryl amine, myristyl amine, palmityl amine, stearyl amine, and oleyl amine. Other commercially available primary amines include coconut oil amine, tallow amine, hydrogenated tallow amine and cottonseed oil amine. Useful secondary amines are dilauryl amine, dimyristyl amine, dipalmityl amines, distearyl amine, dicoconut amine and dihydrogenated tallow amine. In the case of many of the above amines, it will be noted that the source of alkyl substituent on the organic nitrogen is derived from a mixed vegetable oil or animal fat. For purposes of convenience, these compounds have been named from the derivative alkyl-containing components. This system of nomenclature, particularly in the case of alkyl substituents derived from naturally occurring products such as fats, oils and the like, is used for purposes of simplification. It is believed that those familiar with the art will readily understand that the alkyl substituent varies in the case of a coconut substituent with the alkyl groups containing from 8 to 18 carbon atoms in chain length. Similarly, in the case of hydrogenated tallow, the alkyl substituent will vary from about 12 to 20 carbon atoms in chain length.
In addition to using primary or secondary amines as exemplified above, tertiary amines such as octyl dimethyl amine, octadecyl dimethyl amine, octadecyl methyl benzyl amine, hexyldiethylamine, trilaurylamine, tricoconut amine, tricaprylyl amine, and similar type compounds also may be used.
Preferred aliphatic primary monoamines are amines having the general structural formula:
R–NH.sub.2
wherein R is an aliphatic hydrocarbon radical of from 8 to 22 carbon atoms in chain length. A preferred material of this type is the commercial product “Armeen SD” sold by the Armour Industrial Chemical Company which is known generically to the art as Soya amine. As applied to the above formula the R group is mixed aliphatic radical which has the following components:
______________________________________               Percent______________________________________Hexadecyl             10Octadecyl             10Octadecenyl           35Octadecadienyl        45______________________________________
Out of the group of tertiary amines listed above, one of the most effective is dimethyl hydrogenated tallow amine. This preferred species may be considered as an ammonium molecule which has had its three hydrogen atoms replaced by three alkyl groups. Two of these alkyl groups are methyl and the third is a mixed alkyl substituent derived from hydrogenated tallow.
A representative analysis of the mixed radicals of the hydrogenated tallow group is as follows:
______________________________________              Percent______________________________________  Myristic      2  Palmitic      29  Stearic       68  Oleic         1______________________________________
One of the preferred commercial sources of this tertiary amine is “Armeen M2 HT” sold by Armour Industrial Chemical Company.
The polymerized fatty acids are well known and have been described in numerous publications. Excellent descriptions of these materials may be found in Industrial and Engineering Chemistry, 32, page 802 et seq. (1940), and in the text “Fatty Acids” by Klare S. Markley, published by Interscience Publishers, Inc., New York City, 1947, pages 328 to 330. A specific example of such a polymer which has been found to be particularly useful is one which is prepared as a by-product of the caustic fusion of caster oil in the manufacture of sebacic acid. This material is composed primarily of dicarboxylic acids derived by bimolecular addition in an olefinic polymerization where linkage occurs through the opening of at least two unsaturated bonds. Typical properties of a material so obtained are as follows:
______________________________________Acid value               150Saponification value     172Unsaponifiable matter, percent                    3.7Iodine No                36Moisture content, percent                    0.86______________________________________
The material is, of course, not pure but predominantly contains dicarboxylate polymers having about 34 to 36 atoms. A suitable commercial source of this dimer acid is Harchem Division of Wallace and Tiernan, Inc., and is known as “Century D-75 Acid.”
A typical film-forming corrosion inhibitor useful in conjoint activity with MOPA may be prepared by combining 1 weight part of “Armeen SD” with 2.57 weight parts of a polymerized fatty acid obtained as the residue of a dry distillation of caster oil with sodium hydroxide and reacting the mixture with stirring at a temperature of 60° C. for 20 minutes. The final reaction product is then dispersed in equal weight parts of a heavy aromatic solvent.
Another useful film-forming corrosion inhibitor composition is prepared by heating 14 parts of “Armeen M2 HT” to the melting point and adding thereto 36 parts of “Century D-75 Acid.” The mixture was reacted for 10 minutes at 130°-150° F. and the resultant product added to a heavy aromatic solvent in equal proportions by weight of product to solvent.
______________________________________Distillation range  mm        760Initial boiling point               °C.                         171Percent:10                  °C.                         18450                  °C.                         23090                  °C.                         260End point           °C.                         278______________________________________
In reacting the above recited amines with polymerized fatty acids to obtain the film-forming compositions, care should be taken to maintain salt-forming conditions. This is done primarily by using reaction temperatures of from 20° to 100° C., and by avoiding the presence of materials which cause the splitting out of water. This environment is sometimes referred to as “neutralizing conditions”. It is the salt producible from the above listed reactants which is of primary interest in the instant invention. Further care must be taken in conducting the reaction to eliminate the possibility of the presence of free amines in the final reaction product. Reaction proportions conducive to accomplishing this typically include the above recited use of a weight ratio of typical polymer to typical monoamine of 2.57:1.
Additional film-forming compositions that can be used in conjunction with the subject inhibitor include those disclosed in U.S. Pat. No. 3,003,955.
EXAMPLESExample 1
The ability of MOPA to prevent initial condensate corrosion in water-free separation units without forming significant deposits was determined as set forth below. Testing was carried out with MOPA along with other neutralizing amines to determine relative efficacy from the standpoint of preventing corrosion. Also, the ability of MOPA to perform without forming deposits under normal conditions of use was investigated.
A laboratory test unit was constructed to evaluate the invention. The unit consisted of a two-inch diameter, fifteen-tray, glass Oldershaw column fitted with a reboiler and overhead system similar to crude distillation units. Preheated naphtha was charged into the column at Tray 5 where it cascaded downward and mixed with hot vapor rising from the reboiler. Usually, small sidecuts were taken from Tray 10. Warm reflux was pumped from the overhead receiver back to Tray 15 (top tray) to partially cool the hot vapors coming up the column and going overhead.
Either a dipropylene glycol (DPL) and hydrochloric acid complex or dry HCL gas provided hydrochloric acid vapor for the test unit. The acid vapor was injected into the top section of the reboiler. 50 ppm or less of water were present in the unit feed overall (dissolved in the naphtha charged to the unit).
Generally, heated corrosion inhibitor was fed into the reflux line to neutralize the acid vapor coming up the column. Deposit formation was observed visually and by chloride analysis of the charge and effluent streams. At the end of each run, the column head was removed and wash water was poured into the column. This wash water was partially refluxed overhead to remove deposits in the overhead line. The two samples of wash water resulting from washing the column and overhead were analyzed for chlorides obtained from each source and compared with the amount of chlorides charged to the unit.
In order to provide a satisfactory test in a limited amount of time, the test unit was operated on a continuous basis and the amount of hydrochloric acid charged was 50 ppm active basis overhead product–about 15-20 times the level usually observed in a separation unit. Operating conditions were selected to provide a satisfactory test in a 20-24 hour-period.
To evaluate the invention and compare it against a typical wet system amine, the following compositions were tested:
Composition 1: 40% MOPA in heavy aromatic solvent;
Composition 2: 40% Morpholine in heavy aromatic solvent;
Composition 3: 40% 2-methoxyethylamine
The results obtained are reported in Table I.
The key quantitative data relating to inhibitor effectiveness and deposit formation reported is residual chloride in both the column and the overhead. Analysis of Table I shows superior performance for MOPA and methoxyethylamine.

TABLE I__________________________________________________________________________
EVALUATION OF NEUTRALIZERS IN DRY SYSTEMS (HEAVY NAPHTHA CHARGE)RUN
1        2          3        4         5__________________________________________________________________________Amine Inhibitor Composition           1        2          1        2         3Hours Run      20       10         16        8        10Water, %        0        0          0        0         0HCl Injection  DPG/HCl  DPG/HCl    Dry HCl gas                                       Dry HCl gas                                                 Dry HCl gasChlorides Charged, PPM          50       50         50       50        50Basis OH (Overhead)Chlorides in Column, %          18       45         24       39        31Chlorides in OH, %          14       17         35       39        24Chlorides in Solution, %          68       38         36       22        41Flooding       No       Yes        No       Yes       NoVisual Inspection          Clean, Light Oily                   Heavy Deposits                              Clean, Light Oily                                       Tray 15 Plugged,                                                 Clean, Light Oily          Liquid Trays                   Trays 14-15, Walls,                              Liquid Trays                                       Heavy Deposits                                                 Liquid Trays          14-15, Walls, OH                   OH, Condenser                              14-15, Walls, OH                                       Walls, OH,                                                 14-15, Walls, OH                                       Condenser__________________________________________________________________________
EXAMPLE 2
Tests were run to determine the effect of reducing the amount of water present in the overhead upon deposit formation. The laboratory test unit described in Example 1 was used in this experiment. The amine corrosion inhibitor used was 40% morpholine and heavy aromatic solvent. The data is reported in Table II.
Examination of quantitive chloride data and the quantitative visual inspection results indicates that reducing the amount of water present in the overhead from about 4% to about 2% greatly increases the amount of deposits remaining in the column and overhead portion of the test unit. Thus, deposit problems in water-free systems are much more severe than those in wet systems.
TABLE II______________________________________EFFECT OF WATER CONCENTRATIONON DEPOSIT FORMATION (EXXON VM&P NAPHTHA)Amine Inhibitor______________________________________Hours Run*  7           16          20Water, %, Basis OH       2           4.4         4.7Chlorides Charged,       100         100         50PPM Basis OHChlorides in Column, %       64          60          38Chlorides in Column OH, %       6           2           6Chlorides in Solution, %       16          38          52Flooding    Yes         No          NoVisual Inspection       Heavy Deposits                   Heavy Deposits                               Moderate       Tray 15 & Wall                   Tray 15 & Walls                               Deposits                               Tray 15                               & Walls______________________________________ *Not continuous runs
Claims (9)
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We claim:
1. A process for controlling corrosion in water-free petroleum and petrochemical hydrocarbon processing system separation units consisting essentially of adding a corrosion inhibiting amount of a composition having the formula R–O–(CH2)nNH2 wherein n is 2 or 3 and R is a lower aklyl radical of not more than 4 carbon atoms to the hydrocarbon being processed in the separation unit.
2. The method of claim 1 wherein the compound is chosen from the group consisting of methoxypropylamine, methoxyethylamine and ethoxypropylamine.
3. The process of claim 1 wherein the compound is methoxypropylamine.
4. The process of claim 1 wherein the compound is added to the hydrocarbon before said hydrocarbon is passed through the distillation column of the separation unit.
5. The process of claim 1 wherein the compound is added to the overhead line of the separation unit.
6. The process of claim 1 wherein the amount of the compound added to the hydrocarbon is sufficient to raise the pH of the initial condensate to above 4.0.
7. A process for controlling corrosion in water-free petroleum and petrochemical hydrocarbon processing system separation units consisting essentially of adding to the hydrocarbon a corrosion inhibiting amount of a film-forming amine along with a composition having the formula R–O–(CH2)nNH2 wherein n is 2 or 3 and R is a lower alkyl radical of not more than 4 carbon atoms in an amount sufficient to raise the pH of the initial condensate to above 4.0.
8. The method of claim 7 wherein the compound is chosen from the group consisting of methoxypropylamine, methoxyethylamine and ethoxypropylamine.
9. The method of claim 7 wherein the compound is methoxypropylamine.

The effect of hydroquinone and methoxypropylamine on the pitting corrosion behaviour of A-470 low alloy turbine disc steel
VOtieno-AlegoaG.AHope∗H.JFlitt†D.PSchweinsberga
Abstract
Electrochemical techniques have been used to study the pitting corrosion behaviour of A-470 turbine rotor disc low alloy steel (LAS) in a simulated aggressive turbine environment containing 2 ppm NaCl + 2 ppm Na2SO4 + 2 ppm NaOH + 5 ppm SiO2 (30°C) in the presence of hydroquinone (HQ) and methoxypropylamine (MPA), alone or in combination.
Addition of HQ to N2 purged solutions shifts the corrosion potential in the positive direction and spontaneous passivation is observed at concentrations of approximately 100 ppb. HQ concentrations as low as 150 ppb can induce pitting and Scanning Electron Microscopy studies revealed these pits to have been formed primarily at MnS inclusions.
Potentiodynamic polarization has been used to determine the pitting potential (Epit) of the alloy in N2 purged solutions containing different concentrations of MPA between 1 × 10−4 and 1 × 10−3 M. Epit increased with increasing MPA concentration and immunity to pitting corrosion is evident at concentrations above 4 × 10−4 M.
Surface analysis studies show this inhibition to be due to the chemisorption of MPA on the metal.
In case of HQ/MPA mixtures, the pitting corrosion of the alloy by 200 ppb HQ is completely inhibited by 2 × 10−4 M MPA.
The normal practice of adding amines to adjust the pH of turbine feed water acts to counteract the pitting characteristics of HQ at higher concentrations.

A novel anti-corrosive solution was recently patented (US patent 20160024311), which contains methoxy propyl amine (3-methoxypropyl-amine) (MOPA).
MOPA is a colourless and clear liquid with ammoniacal odour, which is soluble in water and other organic solvents (23).
MOPA has been used as a corrosion-inhibitory solution in steam condensate systems. The anti-corrosive effect of MOPA is due to its amine content (24).
The present study aimed to evaluate the effect of different environments including deionised water, blood, PBS and MOPA on the cyclic fatigue resistance of endodontic NiTi rotary instruments. We determined whether MOPA can increase the fatigue resistance due to its anti-corrosive potential under in vitro conditions.

 

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