DE102005008856A1 - Use of ethercaroxylic acid amide compound as corrosion inhibitors in mechanisms for promoting and transporting hydrocarbons in the petroleum promotion and petroleum processing - Google Patents

Abstract

Use of ethercaroxylic acid amide compound (I) as corrosion inhibitors. Use of ethercaroxylic acid amide compound of formula (I) as corrosion inhibitors. R1>1-30C alkyl, 2-30C alkenyl, -CH2-CO-NR2>R3> or aryl (substituted by 1-12C aryl); either R2>, R3>H, 1-6C alkyl or 5-7C cycloalkyl; or NR2>R3>4-8 ring; A : 2-4C alkylene; and n : 1-20. Provided that the ring contains oxygen or nitrogen except carbon, and R2>, R3> is not hydrogen at the same time. [Image].

Description

The The present invention relates to the use of biodegradable Ethercarbonsäureamiden as corrosion inhibitors, in particular in facilities for the promotion and transport of hydrocarbons in oil production and processing.

In technical processes involving metals with water or even with oil-water two-phase systems come into contact, there is a risk of corrosion. Especially in Saltwater systems, as used in oil production and processing occur, this danger is particularly pronounced. Without special additives to protect the equipment used are the exploitation of a deposit and the processing of the oil not possible.

Such Although corrosion inhibitors have long been known, however in many ways not yet optimal. Many products, e.g. Amides / imidazolines from fatty acids and polyamines are too oil soluble and thus in the corrosive water phase due to poor distribution equilibria (Partitioning) only in low concentration available. Accordingly, these are as corrosion inhibitor only slightly or only at high dosage effective.

DE-A-199 30,683 describes amidamines / imidazolines obtained by reaction of polyglycol ether carboxylic obtained with polyamines, and due to their structure a have very good water solubility and thus by good partitioning improved corrosion protection have.

Quaternary alkyl ammonium compounds (Quats) represent alternative anticorrosion agents of the prior art Technique, in addition to the corrosion-inhibiting and biostatic Own properties. Despite improved water solubility show the quats, for example compared to the imidazolines, a significantly reduced film persistence and therefore also lead only in higher Dosing to an effective corrosion protection. Furthermore, the limited poor biodegradability their use in environmentally sensitive Applications.

task Accordingly, it was the object of the present invention to provide new corrosion inhibitors to find, with constant good or improved corrosion protection also an improved biodegradability compared to the Provide corrosion inhibitors of the prior art.

As now, surprisingly has been found, modified polymeric glycol ether have an excellent Effect as corrosion inhibitors and a good biodegradability.

worin
R¹ C₁-C₃₀-Alkyl, C₂-C₃₀-Alkenyl oder eine Gruppe der Formel -CH₂-CO-NR²R³ oder ein C₆-C₁₈-Arylrest, der mit einer C₁-C₁₂-Alkylgruppe substituiert sein kann
R², R³ unabhängig voneinander Wasserstoff, C₁-C₆-Alkyl oder C₅-C₇-Cycloalkyl, oder R² und R³ unter Einschluß des Stickstoffatoms, an das sie gebunden sind, einen Ring von 4 bis 8 Ringatomen bilden, wobei außer Kohlenstoffatomen auch Sauerstoff- oder Stickstoffatome im Ring enthalten sein können, mit der Maßgabe, dass nicht R² und R³ gleichzeitig für Wasserstoff stehen,
A ein C₂-C₄-Alkylenrest
n eine ganze Zahl von 1 bis 20 bedeuten als Korrosionsinhibitoren.The invention therefore relates to the use of compounds of the formula (1)

wherein
R ^{1 is} C ₁ -C ₃₀ -alkyl, C ₂ -C ₃₀ -alkenyl or a group of the formula -CH ₂ -CO-NR ² R ³ or a C ₆ -C ₁₈ -aryl radical which is substituted by a C ₁ -C ₁₂ Alkyl group may be substituted
R ² , R ^{3 are} independently hydrogen, C ₁ -C ₆ -alkyl or C ₅ -C ₇ -cycloalkyl, or R ² and R ³ , including the nitrogen atom to which they are attached, form a ring of 4 to 8 ring atoms in which, apart from carbon atoms, oxygen or nitrogen atoms may also be present in the ring, with the proviso that R ² and R ^{3 are not} simultaneously hydrogen,
A is a C ₂ -C ₄ -alkylene radical
n is an integer from 1 to 20 as corrosion inhibitors.

One Another object of the invention is a method for inhibition corrosion on metal surfaces, in particular of ferrous metals, by a corrosive System in contact with the metal surfaces, at least a compound of formula 1 is added.

R ¹ is preferably C ₄ -C ₁₈ alkyl or C ₈ -C ₁₈ alkenyl. R ² and R ³ are preferably hydrogen, but not simultaneously, or C ₁ -C ₄ alkyl. A is preferably an ethylene radical, n is preferably an integer from 2 to 10.

corrosive Systems according to this invention are preferably liquid / liquid or liquid / gaseous multiphase systems consisting of water and hydrocarbons in free and / or dissolved form contain corrosive components such as salts and acids. The corrosive Ingredients can also gaseous such as hydrogen sulfide and carbon dioxide. hydrocarbons For the purposes of this invention are organic compounds, the ingredients of crude oil / natural gas are, and their derivatives.

The compounds of formula (1) are accessible from polyalkylene glycol monoalkyl ethers or polyalkylene glycols by first converting the polyalkylene glycol into the corresponding alkylated carboxylic acid. This can be done by oxidation of the terminal CH ₂ OH group to the carboxylic acid function or reaction of the alkylene glycol with chloroacetic or acrylic acid derivatives in literature known ways.

Examples of suitable alkylene glycol ethers from which the compounds of the formula 1 are obtainable are polyethylene glycols having molecular weights of 100-1000 g / mol, ethylene oxide / propylene oxide copolymers (block or random copolymers), methyl polyglycols, butyl polyglycols, isobutyl polyglycols, but also glycol ethers based on octanol , 2-ethylhexanol, decanol, isodecanol, dodecanol, tetradecanol, hexadecanol, octadecanol, oleyl alcohol or synthetic or native fatty alcohol cuts. Also suitable are glycol ethers based on alkylphenols having a C ₁ -C ₁₂ -alkyl group.

The obtained ether carboxylic acids then, with elimination of water, the corresponding mono- or dialkylamines to the corresponding ether carboxamide around. The amidation can be used with and without the use of catalysts Reaction temperatures between 80 and 200, preferably between 100 and 180 ° C done.

Suitable amines are amines having 1-10 carbon atoms such as methylamine, ethylamine, propylamine, n-butylamine, isobutylamine, sec-butylamine, pentylamines, hexylamines, dimethylamine, diethylamine, dipropylamine, dibutylamine, diisopropylamine, diisobutylamine, pyrrolidine, piperidine, morpholine, or also substituted amines such as ethanolamine or diethanolamine. Particularly suitable are amines having C ₃ -C ₅ -alkyl radicals or cyclic amines having 5 to 7 chain members, particular preference is given to diethylamine, isopropylamine, isobutylamine, isopentylamine, piperidine and pyrrolidine.

The Compounds of the invention can alone or in combination with other known corrosion inhibitors be used. In general, so much of the corrosion inhibitor of the invention insert that under the given conditions a sufficient Receives corrosion protection. Preferred use concentrations based on the pure compounds according to the invention are 5 to 5000 ppm, preferably 10 to 1000, in particular 15 to 150 ppm.

Especially also suitable as corrosion inhibitors are mixtures of the products according to the invention with other corrosion inhibitors known in the literature, such as amidamines and / or imidazolines from fatty acids and polyamines and their salts, quaternary ammonium salts, ethoxylated / oxpropylated Amines, amphoglycinates and propionates, betaines or compounds described in DE-A-19930683.

example 1

Butyl polyglycol ether carboxylic isobutylamide:

In a 250 ml four-necked flask with stirrer and distillation bridge were under nitrogen atmosphere 92.0 g (0.27 mol, molar weight determined by acid number, via Williamson ether synthesis obtained from this precursor) of an ether carboxylic acid based on butanol + 3.5 Submitted ethylene oxide and at 150 ° C. distilled off the amount of water contained 11.6 g. Well were a total of 29.6 g (0.40 mol) of isobutylamine over a period of 6 h added dropwise and in each case an amine-water mixture distilled off. Final reaction water was at 135 ° C / 25 mbar distilled off and the sample is then filtered hot. This gives 101 g a clear, brownish Liquid, acid number 7.9 mg KOH / g, amide nitrogen 4.1% by weight, which dissolves opaque in water.

Example 2

Butyl polyglycol ether carboxylic pyrrolidine:

Analogous Example 1 was prepared from 350 g (1.00 mol) of an ether carboxylic acid Butanol + 3.5 ethylene oxide and 142 g pyrrolidine (2.00 mol) base 327 g of a brown, clear oil isolated, acid number 7.4 mg KOH / g, amide nitrogen 3.9 wt .-%, which is clear in water solves.

Example 3

PEG 400-ether dicarboxylic acid bis-isobutylamide:

Analogous Example 1 was prepared from 243 g (0.259 mol) of a dietherocarboxylic acid Based on polyethylene glycol 400 (contains water, approx. 58% active substance) and 87.9 g of isobutylamine (1.20 mol) 170 g of a brown, clear oil isolated, acid number 20.9 mg KOH / g, amide nitrogen 4.4% by weight, which is clear in water solves.

Example 4

Methylpolyglycol-ether carboxylic acid isobutylamide

Analogous Example 1 was prepared from 150 g (0.40 mol) of an ether carboxylic acid Base of a medium molecular weight methyl polyglycol of 350 g / mol (anhydrous) and 34.3 g of isobutylamine (0.47 mol) 156 g of a brown, clear oil isolated, acid number 3.0 mg KOH / g, amide nitrogen 3.1% by weight, clear in water solves.

Example 5

Emulsogenic COA 070-isobutylamide

Analogous to Example 1 were from 329.4 g (0.50 mol by acid number) an ether carboxylic acid based on C14 / 15-oxoalcohol + 7 ethylene oxide and 55.1 g of isobutylamine (0.75 mol) 303 g of a brown, clear oil with acid number 2.3 mg KOH / g and amide nitrogen 1.93 wt .-% isolated.

Example 6

Analogous Example 1 was prepared from 538 g (1.00 mole by acid number) of an ether carboxylic acid Base n-octanol + 8 ethylene oxide and 82.8 g isobutylamine (1.13 mol) 511 g of a brown, clear oil with acid number 3.2 mg KOH / g and amide nitrogen 2.34 wt .-% isolated.

Example 7

Analogous Example 1 was prepared from 787 g (1.00 mole by acid number) of an ether carboxylic acid Base oleyl / cetyl alcohol + 8 ethylene oxide and 87.8 g isobutylamine (1.20 mol) 715.4 g of a brown, clear oil with acid number 2.1 mg KOH / g and amide nitrogen 1.78 wt .-% isolated.

effectiveness the compounds of the invention as corrosion inhibitors

The compounds according to the invention were tested as corrosion inhibitors in the Shellwheel test. Carbon steel coupons (DIN 1.1203 with 15 cm ² surface) were immersed in a salt water / petroleum mixture (9: 1.5% NaCl solution with acetic acid to pH 3.5) and at a rotational speed of 40 rpm at 70 ° C for 24 hours exposed to this medium. The dosage of the inhibitor was 50 ppm of a 40% solution of the inhibitor. The protective values were calculated from the mass decrease of the coupons, based on a blank value.

In In the following tables, "comparison" refers to a residue amine quat Base dicocoalkyl dimethyl ammonium chloride (corrosion inhibitor of the prior art).

Table 1: (SHELL wheel test)

The Products were as well tested in the LPR test (test conditions analogous to ASTM D 2776).

Table 2: (LPR test)

As can be seen from the above test results, show the products of the invention very good corrosion protection properties at low dosage on. The compounds are biodegradable, as follows will be shown.

Table 3: (according to OECD 306)

Claims (6)

Use of compounds of the formula (1)

wherein R ^{1 is} C ₁ -C ₃₀ -alkyl, C ₂ -C ₃₀ -alkenyl or a group of the formula -CH ₂ -CO-NR ² R ³ or an aryl radical which is substituted by a C ₁ -C ₁₂ -alkyl radical R ² , R ^{3 are} independently hydrogen, C ₁ -C ₆ alkyl or C ₅ -C ₇ cycloalkyl, or R ² and R ³ , including the nitrogen atom to which they are attached, form a ring of 4 to 8 ring atoms, wherein Besides carbon atoms, oxygen or nitrogen atoms may also be present in the ring, with the proviso that R ² and R ^{3 are not} simultaneously hydrogen, A is a C ₂ -C ₄ -alkylene radical n is an integer from 1 to 20 as corrosion inhibitors. Use according to claim 1, wherein R ^{1 is} C ₄ -C ₁₈ alkyl. Use according to claim 1, wherein R ^{1 is} C ₈ -C ₁₈ alkenyl. Use according to claim 1 to 3, wherein R ² and R ³ independently of one another are hydrogen or C ₁ -C ₄ -alkyl. Use according to claim 1 to 4, wherein A is for a Ethylene radical is. Use according to claim 1 to 5, wherein n is a number from 2 to 10 means.