EP0191952B1 - Salts of alkenylsuccinamic acids, process for their preparation and their use as corrosion inhibitors - Google Patents

Description

The problem of corrosion arises in all processes of oil production and processing in which metals containing iron or iron come into contact with aqueous systems. The problems associated with exposure to salt water, carbonic acid and hydrogen sulfide are particularly serious. Amines or quaternary ammonium compounds are mostly used as corrosion inhibitors. However, the protective effect of the known commercial products is often inadequate or deteriorates after a short time, since the composition of freshly extracted crude oil is constantly changing. In particular, the corrosive components increase in the course of funding if, for. B. is flooded with salt water to increase the field yield. There is therefore a need worldwide for new, better-acting anti-corrosion agents and the demands are increasing.

It has now been found that by using the amidamine salts of alkenylsuccinic acid halamides described below, an excellent corrosion protection effect for water-in-oil emulsions, such as are present in petroleum, can be achieved.

Various succinic acid derivatives are already known as anti-corrosion agents. So z. B. alkyl or alkenylsuccinic acid semi-ester described in US Patent 4,053,426, which are used in the form of the amine salts for lubricants and aqueous metalworking fluids. US Patent 4,235,874 describes alkenyl succinic acid or anhydride and triesters of triethanolamine as corrosion inhibitors for refined petroleum products. For the same fields of application, US Pat. No. 4,148,605 describes ester dicarboxylic acids which are obtained by reacting alkenylsuccinic anhydride with hydroxycarboxylic acids.

Certain succinic acid half-amides are also known: for example, US Pat. No. 2,490,744 lists reaction products of alkenylsuccinic anhydrides with primary amines in a molar ratio of 1.25 to 2: 1 as rust inhibitors in lubricating oils, the total number of carbon atoms in the reaction product being said to be between 28 and 50 .

In addition, the German Offenlegungsschrift 3,300,874 alkanolamine salts of alkenylsuccinic acid half-amides are described as corrosion inhibitors for aqueous systems; these compounds are prepared by reacting alkenylsuccinic anhydrides with primary C ₁ -C ₁₀ amines and subsequent neutralization with C ₂ -C ₄ alkanolamines. Further alkenylsuccinic acid halamides and their use as anti-corrosion agents are known from German Offenlegungsschriften 3319183 and 3341 013. The use of succinic acid halamides as corrosion inhibitors in petroleum production and processing is not yet known.

From US-A 4332737 rust inhibitors are known which are obtained by reacting dicarboxylic acids with acylated polyalkylene polyamines. However, these products are not salts of dicarboxylic acids and polyalkylene polyamines, but the dicarboxylic acid is bound here to the amino group solely by acylation.

wobei R¹ C₆-C₁₀₀-, vorzugsweise C₉-C₂₂-Alkenyl, A den protonierten Rest eines Amidamins der Formel II

R² C_S-C₂₂-, vorzugsweise C₁₀-C₁₈-Alkyl, C₅-C₂₂-, vorzugsweise C₁₀-C₁₈-Alkenyl oder Cycloalkyl, R³ eine Gruppe der Formel

R⁴ entweder eine Gruppe der Formel -COR² und gleichzeitig R₅ Wasserstoff oder R⁴ und R⁵ gleichzeitig die gleiche Bedeutung wie R³ haben, Y Wasserstoff oder Methyl, n eine Zahl von 0 bis 12 und x eine Zahl von 1 bis 3 bedeuten. Cycloalkyl unter R² bedeutet vorzugsweise solche Gruppen, die sich von den Naphthensäuren herleiten.The invention relates to salts of alkenylsuccinic acid halamides of the formulas

where R ^{1 is} C ₆ -C ₁₀₀ , preferably C ₉ -C ₂₂ alkenyl, A is the protonated residue of an amidamine of the formula II

R ² C _S -C ₂₂ -, preferably C ₁₀ -C ₁₈ alkyl, C ₅ -C ₂₂ -, preferably C ₁₀ -C ₁₈ alkenyl or cycloalkyl, R ^{3 is} a group of the formula

R ^{4 is} either a group of the formula -COR ² and simultaneously R _{5 is} hydrogen or R ⁴ and R ^{5 are} simultaneously the same as R ³ , Y is hydrogen or methyl, n is a number from 0 to 12 and x is a number from 1 to 3 mean. Cycloalkyl under R ² preferably means those groups which are derived from the naphthenic acids.

The salts of the formulas Ia and Ib are prepared by first reacting an alkenylsuccinic anhydride with excess ammonia, giving the ammonium salts. The reaction can be carried out in an inert organic solvent such as petroleum ether or toluene with gaseous ammonia, the ammonium salt crystallizing out; however, the reaction can just as well be carried out with aqueous ammonia, the ammonium salt being obtained in the form of an aqueous solution.

The salts according to the invention are then prepared from these alkenylsuccinic acid-half-amide ammonium salts by heating in aqueous solution at about 100 ° C. with an amidamine of the formula II, ammonia escaping. The amidamines are prepared by amidation at about 150 to 160 ° C. of carboxylic acids with amines such as diethylene triamine, triethylene tetramine or tetraethylene pentamine and optionally subsequent oxyalkylation with ethylene oxide or propylene oxide under customarily known reaction conditions.

The solutions of the compounds according to the invention obtained in the synthesis can be used directly without isolation of the end product. These solutions are expediently diluted with a suitable solvent, for example with a low alcohol, and adjusted to a concentration of about 30 to 50% of active substance. A good corrosion protection effect is obtained by adding this commercial product in quantities of 5 to 100, preferably 10 to 50 ppm to the petroleum or petroleum products.

General working instructions for Examples 1-4

2 moles of ammonia are placed in the form of an approximately 25% aqueous solution in a reaction vessel. 1 mol of an alkenylsuccinic anhydride is then slowly added dropwise with stirring, the internal temperature being kept at 0-5 ° C. by cooling. The mixture is then stirred for a further 2 hours at room temperature, whereupon 1 mol of an amidamine (formula II) is added. The temperature is then raised to 100 ° C., ammonia escaping and water being distilled off. After 2 hours, the mixture is allowed to cool and the desired solvent (for example isobutanol or methanol) is added and the mixture is filled off.

example 1

According to the general working procedure, 136 g (2 mol) 25% ammonia are first reacted with 224 g (1 mol) tripropenylsuccinic anhydride. Then 607 g (1 mol) of amidamine II (made from 2 mol of tallow fatty acid and 1 mol of diethylene triamine) are added

R = alkyl chain of tallow fatty acid and proceeds as described in the general instructions. After the end of the reaction, 848 g of isobutanol are added and a yellow solution with an active substance content of 50% is obtained.

Example 2

According to the general procedure, 136 g (2 mol) of ammonia (25%) are reacted with 266 g (1 mol) of tetrapropenyl succinic anhydride. 780 g (1 mol) of amidamine II ₂ (prepared from 2 mol of naphthenic acid, 1 mol of diethylene triamine and 3 mol of ethylene oxide) are added

R = alkyl skeleton of naphthenic acid and proceeds as described in the general instructions. Finally, put 1 060 g Methanol, whereupon one contains a brown solution which contains 50% of the active substance.

Example 3

• R = Alkylkette der Tallölfettsäure x + y = 6
  und verfährt weiter wie in der allgemeinen Vorschrift beschrieben. Nach Zusatz von 1 255 g Methanol erhält man eine braune Lösung mit einem Wirkstoffgehalt von 50 %.

According to the general procedure, 136 g (2 mol) of ammonia (25% aqueous) are first reacted with 224 g (1 mol) of tripropenylsuccinic anhydride. Then 1,020 g (1 mol) of amidamine 11 ₃ (prepared from 2 mol of tall oil fatty acid, 1 mol of triethylene tetramine and 6 mol of propylene oxide) are added

• R = alkyl chain of tall oil fatty acid x + y = 6
  and continues as described in the general regulation. After adding 1 255 g of methanol, a brown solution with an active substance content of 50% is obtained.

Example 4

• R = Alkylkette der Talgfettsäure x + y + z = 12
  und verfährt weiter wie in der allgemeinen Vorschrift beschrieben. Nach Zugabe von 1 600 g Isobutanol erhält man eine braune Lösung, die die Wirksubstanz zu 50 % enthält.

According to the general procedure, 136 g (2 mol) of ammonia (25% aqueous) are first reacted with 350 g (1 mol) of octadecenylsuccinic anhydride. 1,250 g (1 mol) of amidamine 11 ₄ (prepared from 2 mol of tallow fatty acid, 1 mol of tetraethylene pentamine and 12 mol of ethylene oxide) are then added

• R = alkyl chain of tallow fatty acid x + y + z = 12
  and continues as described in the general regulation. After adding 1,600 g of isobutanol, a brown solution is obtained which contains 50% of the active substance.

Example 5

• R = Alkylgerüst der Naphthensäure
  und verfährt weiter wie in der allgemeinen Vorschrift beschrieben. Nach Reaktionsende werden 625 g Toluol zugesetzt und man erhält eine braune Lösung mit einem Wirkstoffgehalt von 50 %.

According to the general procedure, 136 g (2 mol) of ammonia (25%) are first reacted with 224 g (1 mol) of tripropenylsuccinic anhydride. Then 385 g (1 mol) of amidamine 11 ₅ (prepared from 1 mol of naphthenic acid and 1 mol of diethylene triamine) are added

• R = alkyl skeleton of naphthenic acid
  and continues as described in the general regulation. After the end of the reaction, 625 g of toluene are added and a brown solution with an active substance content of 50% is obtained.

The test described below shows the excellent corrosion protection properties of this connection class. For comparison, the commercial products Visco 938 and Servo CK 378 were also tested.

A dynamic test (so-called “wheel test”) was used to test the inhibitor compositions, a method with which the corrosion inhibitors for oil and gas production are tested.

Steel sheets measuring 130 mm x 10 mm x 1 mm were chosen as test coupons. These strips of metal were sanded, degreased with toluene and weighed. Kerosene, which contained salt water with 5% by weight NaCl, based on water, was used as the test medium. The emulsion contained 90% by weight of salt water and was saturated with H ₂ S or Co ₂ .

Then 10, 20 and 50 ppm - based on the weight of the emulsion - of inhibitor were added.

The degreased and weighed sheets were then introduced into the emulsions and subjected to a mechanical movement (40 rpm by means of a shaft rotating the test vessels) at 70 ° C. for 24 hours. subjected.

The test sheet strips were then cleaned with an inhibiting acid, degreased and weighed after drying to determine the weight loss. The corrosion rates are given in mpy (mills per year) (39.4 mpy = 1 mm / year). For comparison, the blank value (test without addition of inhibitor) was determined.

The results obtained with this test method are summarized in the following table.

(See table on page 6 f.)

Claims (3)

1. A salt of an alkenylsuccinic acid monoamide of the formulae

wherein R¹ is C₆-C1₀₀-alkenyl, preferably C₉-C₂₂-alkenyl, A is the protonized radical of an amidoamine of the formula II

R² is C₅-C₂₂-alkyl, preferably C₁₀-C₁₈-alkyl, C₅-C₂₂-alkenyl or cycloalkyl, preferably C₁₀-C₁₈-alkenyl or cycloalkyl, R³ is a group of the formula

R⁴ is either a group of the formula -COR², R⁵ at the same time being hydrogen, or R⁴ and R⁵ at the same time have the same meaning as R³, Y is hydrogen or methyl, n is a number from 0 to 12 and x is a number from 1 to 3.

2. A process for the preparation of the compounds as claimed in claim 1, wherein an alkenylsuccinic anhydride of the formula

is reacted with ammonia and the resultant alkenylsuccinic acid monoamide ammonium salts are further reacted with an amidoamine of the formula

3. Use of the compounds as claimed in claim 1 as corrosion inhibitors in water-in-oil emulsions.