CZ69193A3 - Corrosion inhibiting preparations - Google Patents

Abstract

The present invention relates to corrosion inhibitors which are characterised by a content of amine-free salt of a half-ester of an alkylsuccinic or alkenylsuccinic acid, the alkyl or alkenyl substituents thereof containing 8 to 30 carbon atoms, preferably 9 to 15 carbon atoms.

Description

Technical field

The invention relates to anti-corrosion agents for use in many metal processing fields where it is concerned to protect used metal parts from rust.

BACKGROUND OF THE INVENTION

Conventional anticorrosive agents include components such as petroleum fraction sulfonates, alkylsulfonamidocarboxylic acid salts, and amine salts of alkyl succinic acid or alkenylsuccinic acid semi-ester.

DE-A-26 40 854 discloses lubricant formulations having anticorrosive properties based on the amine salts of the alkyl succinic acid or alkenylsuccinic acid semi-halide.

EP-A-336 467 discloses anti-corrosion agents based on alkylarylsulfonic acids, alkanolamine and a semi-ester of alkyl succinic or alkenylsuccinic acid.

It has been shown that sulfur-containing compounds such as alkylarylsulfonic acids, petroleum fraction sulfonates or alkylsulfonamidocarboxylic acid salts can be readily degraded by microorganisms such as sulfur reducing bacteria. Nitrogen-containing corrosion protection agents, in particular secondary amines, can, for example, be chemically converted into health-threatening nitrosamines.

-2.With regard to the use of non-corrosive anti-corrosion agents, it is important to prepare non-nitrogen-containing, non-nitrogen-containing, non-nitrogen-containing agents in particular,

The essence of the invention

SUMMARY OF THE INVENTION It is an object of the present invention to provide amine-free anti-corrosion agents which prevent the formation of health hazards such as nitrosamines.

It has surprisingly been found that salts, in particular alkali metal salts and alkaline earth metal salts of alkyl succinic or alkenyl succinic acid semi-esters can be used as anticorrosion agents and thus the risk of nitrosamines can be avoided.

The present invention provides anti-corrosion agents comprising salts of alkyl succinic or alkenylsuccinic acid semi-esters whose alkyl or alkenyl substituents contain 8 to 30 carbon atoms, preferably 9 to 15 carbon atoms, and which do not contain an amino group.

Salts which do not contain an amino group, in particular alkali metal salts and alkaline earth metal salts, are obtained by esterification of an alkyl succinic or alkenyl succinic anhydride with an alcohol, preferably in equimolar amounts, optionally using a catalyst additive such as an alcoholate solution at temperatures up to the boiling point , preferably 20 ° C to boiling point, particularly preferably 40 to 80 ° C. The reaction is preferably carried out in a protective manner

-3atmosphere of nitrogen. A preferred embodiment is to stir the solution after addition of the alcohol at a temperature of up to the boiling point of the solution, preferably 60 ° C to the boiling point of the solution. The semi-esters obtained are then treated with dilute lye to pH greater than 7. around 9.

The semi-ester is derived from an alkylsuccinic or alkenylsuccinic acid in which the alkyl or alkenyl substituent contains 8 to 30 carbon atoms, preferably 9 to 15 carbon atoms. Examples of such succinic acids are octenyl antaric, dodecenyl antaric, hexadecenyl antaric isooctadecenylsuccinic or triacontenylsuccinic acid The substituent groups may also be polyolefinic groups such as a tripropenyl, tetrapropenyl or pentapropenyl radical.

The alcohol used to form the semi-ester preferably has 1 to 15 carbon atoms and preferably contains an alkyl alcohol (alkanol) such as methanol, ethanol, propanol or butanol.

The lyes to which the substituted succinic acid semi-esters react are preferably aqueous hydroxide solutions such as sodium hydroxide or potassium hydroxide. Aqueous solutions of polyvalent metal hydroxides such as alkaline earth metal hydroxides are also suitable.

The aqueous solutions of the salts of alkylsuccinic or alkenylsuccinic acid which do not contain an amine group can be used directly as anti-corrosion agents without further purification.

Salts which do not contain an amino group are

Applicable as aqueous anti-corrosion agents, they are preferably used in a concentration of 0.5 to 65% by weight, particularly preferably 1 to 10% by weight, based on the aqueous solution. The pH of the aqueous anti-corrosion agents is higher than pH 7, preferably having a pH of about 9.

Salts which do not contain an amino group can also be used as anti-corrosion agents in admixture with other compounds.

Such anticorrosion agents consist, for example, of up to 80% by weight to 1% by weight to 1% by weight to 0% by weight, of a salt of an alkylsuccinic acid or an alkenylsuccinic acid, an oxethylate of the formula -0-O- (CH ₂ CH ₂ O) _n H, ¹ is alkyl having a carbon number of ^C io ~ ^c 22 ^{'and l-en-yl having a} carbon number _of C ₁₀ -C ₂₂ or aIkary1 n is 1 to 10, preferably 1-5 fatty acid of the formula R ² -COOH wherein R ² means an alkyl having a carbon number of C ₁₀ -C ₂₂ or an alkenyl having a carbon number of ^C 10 ^-C 30 of an ether carboxylic acid of the formula

R ³ -O- (CH ₂ CH ₂ O) _n -CH ₂ -COOH, where R ³ is alkyl having a carbon number of ^C io ^"c 22" ^alkene yl

With a number of carbons of C ₁₀ -C ₂₂ or alkaryl and n is 1 to 10, preferably 1 to 5.

Such anti-corrosion agents are characterized by excellent solubility in combination with water. When mixed with water, they form finely dispersed emulsions, which may be clear (opaque), opal or milky.

Mixtures of the aforementioned non-amine salts of alkyl succinic or alkeynylsuccinic polyesters with oxethylates, fatty acids and optionally ether carboxylic acids are preferably used with mineral oils in an amount of up to 70% by weight of the mineral oil based on the total weight and exhibit good anti-corrosion properties.

Suitable mineral oils are mineral oils which consist of paraffin, naphthenes as well as partially aromatics and usually have a viscosity of 25 to 30 mm ² / s, measured at 20 ° C.

The foregoing mixtures of amine-free salts, oxethylates, fatty acids and optionally ether carboxylic acids exhibit an emulsifying and corrosion-inhibiting effect in aqueous mineral oil processing aids.

The term metal processing aids also includes cooling and lubricating agents.

Aqueous solutions of salts not containing an amine group

-6 to a concentration of 0.1 to 10% by weight, preferably 1 to 5% by weight, of polyesters of alkyl succinic or alkenyl succinic acid with oxethylates, fatty acids and, optionally, ether carboxylic acids and mineral oils, are preferably used as anticorrosive agents, with particular regard to good stability in hard water environment show good results.

The test results below show that the amine-free salts of the invention are effective as anti-corrosion agents.

Table 1 shows the corrosion inhibiting effects of an aqueous alkaline solution of amine-free salts.

Table 2 shows the corrosion inhibiting effect of the composition.

The corrosion inhibiting effect was determined based on the Herbert test (DIN 51360/1) and the filter paper test (DIN 51360/2).

DETAILED DESCRIPTION OF THE INVENTION

Example 1

Sodium tripropenylsuccinic acid monomethyl ester

224.0 g (1.0 mol) of tripropenylsuccinic anhydride and 0.5 g (30% by weight) of sodium methanolate solution are used as feed. At a temperature of 45-55 ° C, 35.2 g (1.1 mol) of methanol (technical) are added dropwise over 15 minutes under a nitrogen atmosphere. It is then stirred for 5 hours at 65

-11 ° C. At a pressure of about 40 µm Hg, excess methanol (distillate: 3.3 g) is distilled off at an internal temperature of up to 100 ° C. 250.0 g of an orange-colored product are obtained, which is converted to the sodium salt by addition of a 33% aqueous sodium hydroxide solution (pH ca. 9).

Example 2

Sodium triphenylsuccinic acid monoisobutyl ester

224.0 g (1.0 mol) of tripropenylsuccinic anhydride are introduced and preheated to 80 ° C. At 80 ° C, dropwise dropwise over 30 minutes under a nitrogen atmosphere

74.1 g (1.0 mol) of isobutanol. Subsequently, it is stirred for 5 hours at 105 ° C. 297.4 g of an orange-colored clear liquid are obtained, which is converted to the sodium salt by addition of a 33% aqueous sodium hydroxide solution (pH ca. 9).

Example 3

Tetrapropenylsuccinic acid monoisopropyl ester sodium

266.0 g (1.0 mol) of tetrapropenylsuccinic anhydride are introduced and preheated to 80 ° C. At 80 ° C, dropwise dropwise over 30 minutes under a nitrogen atmosphere

60.1 g (1.0 mol) of isopropanol. It is then stirred for 12 hours at 80 ° C. 299.2 g of a clear oily substance are obtained, which is converted to the sodium salt by addition of a 33% aqueous sodium hydroxide solution (pH ca. 9).

-8Example 4

Tetrapropenylsuccinic acid monoisobutyl ester sodium salt

266.0 g (1.0 mol) of tetrapropenylsuccinic anhydride are introduced and preheated to 80 ° C. At 80 ° C, dropwise dropwise over 30 minutes under a nitrogen atmosphere

74.1 g (1.0 mol) of isobutanol. It is then stirred for 5 hours at 105 ° C. 338.4 g of a clear oily substance are obtained, which is converted to the sodium salt by addition of a 33% aqueous NaOH solution (pH ca. 9).

Example 5

Pentapropenylsuccinic acid monomethyl ester sodium salt

348.0 g (1.0 mol) of pentapropenylsuccinic anhydride and 0.5 g (30% by weight) of sodium methanolate solution are introduced as catalyst. At 50 ° C, 26.9 g (0.84 mol) of methanol (technical) are added dropwise (slightly exothermic reaction) under nitrogen atmosphere over 30 minutes. Subsequently, it is stirred for 4 hours at 105 ° C. 372.4 g of a brown clear oily liquid are obtained, which is converted to the sodium salt by addition of a 33% aqueous sodium hydroxide solution (pH ca. 9).

Example 6

Pentapropenyl antaric acid monoisopropyl ester sodium salt

348.0 g (1.0 mol) of pentapropenyl succinic anhydride are introduced. At 80 ° C under nitrogen atmosphere

509 g (0.84 mol) of isopropanol are added dropwise over 40 minutes. It is then stirred for 12 hours at 80 ° C. 394.6 g of a brown clear oily liquid are obtained, which is converted to sodium salt by addition of a 33% aqueous NaOH solution (pH ca. 9).

Example 7

Monomethyl sodium C _12/14 -alkenyljantarové

138.0 g (0.5 mol) of O 2/ _4- alkenylsuccinic anhydride and 0.5 g (30% by weight) of sodium methoxide solution are introduced and heated to 50 ° C. At 50 ° C, 16.1 g (0.5 mol) of methanol are added dropwise over 15 minutes under a nitrogen atmosphere. It is then stirred for 5 hours at 65 ° C. 148.2 g of a yellowish clear liquid are obtained, which is converted to the sodium salt by addition of a 33% aqueous NaOH solution (pH ca. 9).

Example 8

Sodium salt of _C12 / _14- alkenyl antaric acid monoisopropyl ester

414.0 g (1.5 mol) of 012/14-alkenylsuccinic anhydride are introduced and heated to 80 ° C. At 80 ° C, dropwise dropwise over 30 minutes under a nitrogen atmosphere

90.2 g (1.5 mol) of isopropanol. It is then stirred for 12 hours at 80 ° C. 503 g of a yellow clear product are obtained, which is converted to the sodium salt by addition of a 33% aqueous NaOH solution (pH ca. 9).

-10Table 1

Example 1 2 3 4 Appearance / 20 ° C red red red red Brown Brown Brown Brown clear clear clear clear kapa- kapa- kapa- kapa- lina lina lina lina pH value 9.0 9.1 9.1 8.9 1 wt. solution v dest. H ₂ 0 Emulsion stability 3 wt. solution 0 ° dH instantaneous clear clear clear clear 0 ° dH after 24 h opal opal opal opal 20 ° dH instantaneous strongly strongly strongly strongly opal opal opal opal 20 ° dH after 24 hr. dairy dairy dairy dairy Protection against co- none none none none rozi podle rust, rust, rust, rust, DIN 51360/1 none none none none 2 wt. black black black black spots spots stains stains DIN 51360/2 none none none none 2 wt. rust rust rust rust

-11Table 1 (completion)

Example 5 6 7 8 Appearance / 20 ° C red red yellow- yellow- Brown Brown Brown Brown clear boat paste paste kapa- kapa- lina lina pH value 9.0 9.0 9.1 8.9 1 wt. solution v dest. H ₂ O Emulsion stability 3 wt. solution 0 ° dH instantaneous clear clear clear clear 0 ° dH after 24 h opal opal clear clear 20 ° dH instantaneous strongly strongly opal opal opal opal 20 ° dH after 24 hr. dairy dairy opal opal Protection against co- none none none none rozi podle rust, rust, rust, rust, DIN 51360/1 none none none none 2 wt. black black black black spots spots stains stains DIN 51360/2 none none none none 2 wt. rust rust rust rust

-12—

Table 2

Example 1 2 3 4 Emulgovaný končen- Brown, Brown, Brown, Brown, - loss of 30% by weight cira clear clear clear %, 5 wt. kapa- kapa- kapa- kapa- oleyl alcohol + 2 mol lina lina lina lina EO, 5 wt% acid , 60% mas.naft.mineral. oils Emulsifiability spon- spon- spon- spon- tánní tánní tánní tánní Emulsion stability 3 wt. solution 0 ° dH instantaneous dairy, dairy, dairy, dairy, opales- opales- opales- opales- kuj ící kuj ící kuj ící kuj ící emulsion emulsion emulsion emulsion 0 ° dH after 24 h nezrně- nezrně- unchanged- unchanged- unaffected unaffected unaffected unaffected 20 ° dH instantaneous dairy, dairy, dairy, dairy, opales- opales- opales- opales- kuj ící forging forging forging emulsion emulsion emulsion emulsion 20 ° dH after 24 hr. nezrně- unchanged- unchanged- unchanged- unaffected unaffected unaffected unaffected Protection against co- none none none none rozi podle rust, rust, rust, rust, DIN 51360 / 1.3% none none none none black black black black spots spots spots spots DIN 51360 / 2.3% none none none none rust rust rust rust

-13Table 2 (completion)

Example 5 6 7 8 Emulgovaný končen- Brown, Brown, yellow- yellow- - loss of 30% by weight clear clear Brown, Brown, %, 5 wt. kapa- kapa- clear clear oleyl alcohol + 2 mol lina lina kapa- kapa- EO, 5 wt% acid lina lina , 60% mas.naft.mineral. oils Emulsifiability spon- spon- over over tánní tánní stage stage gel gel Emulsion stability 3 wt. solution 0 ° dH instantaneous dairy, dairy, dairy, dairy, opales- opales- opales- opales- kuj ící forging kuj ící kuj ící emulsion emulsion emulsion emulsion 0 ° dH after 24 h nezrně- nezrně- nezrně- nezrně- néná néná néná néná 20 ° dH instantaneous dairy, dairy, dairy, dairy, opales- opales- opales- opales- forging kuj ící forging kuj ící emulsion emulsion emulsion emulsion 20 ° dH after 24 hr. nezrně- nezrně- nezrně- unchanged- néná . néná néná néná Protection against co- none none none none rozi podle rust, rust, rust, rust, DIN 51360 / 1.3% none none none none black black black black spots spots spots spots DIN 51360 / 2.3% none none none none rust rust rust rust

- 14 -

Industrial applicability

The anticorrosion compositions of the present invention based on salts of the alkyl ester of alkali succinic acid or alkenylsuccinic acid which do not contain an amine group and can be used as corrosion inhibitors in aqueous metal working aids, as cooling and lubricating liquids, while showing good stability and no health hazard.

-15PATENT CLAIMS

Claims (10)

PATENT CLAIMS CLAIMS 1. Corrosion agents, characterized in that they contain salts of alkyl esters of alkyl succinic or alkenylsuccinic acid which do not contain an amino group, the alkyl or alkenyl substituents of which contain 8 to 30 carbon atoms, preferably 9 to 15 carbon atoms. 2. A composition according to claim 1 wherein the salt is an alkali metal or alkaline earth metal salt. Composition according to claim 1 or 2, characterized in that the semi-ester is a semi-ester of an alkyl or alkenylsuccinic acid and an alcohol having 1 to 15 carbon atoms, preferably 1 to 4 carbon atoms. Composition according to one of Claims 1 to 3, characterized in that the succinic acid semi-ester consists of a polyolefin-succinic acid polyester, preferably tri-, tetra- or pantapropenyl antaric acid. Composition according to one of Claims 1 to 4, characterized in that it contains 0, 5 to 65% by weight, preferably 1 to 10% by weight, of the salt not containing the amine group of alkyl or alkenylsuccinic acid semi-esters, based on the aqueous solution. - 16 - The composition of claim 1 comprising 40 to 80% by weight 30 to 1% by weight 30 to 1% by weight 30-0% by weight of a salt of a monoester of alkyl or alkenylsuccinic acid, oxethylátů formula wherein R ¹ is alkyl having a carbon number of ^C 10 ^_C 22 'alkenyl having a carbon number _of C ₁₀ -C ₂₂ alkaryl and n is equal to 1-10, preferably 1-5, fatty acid of formula R ² -COOH wherein R ² is alkyl having a carbon number _of C ₁₀ -C ₂₂ alkenyl or a carbon number of ^C 10 ^"C 30 ether carboxylic acids of formula R ³ -0- (CH2CH2O) n-CH2-COOH, wherein R ³ is alkyl having a carbon number of C 10 -C _22, alkenyl having a carbon number _of C ₁₀ -C ₂₂ alkaryl and n is equal to 1-10, preferably 1-5 . 7. A composition according to claim 6 comprising up to 70% by weight of the mineral oil, based on the total weight. Composition according to claim 6 or 7, characterized in that it comprises 0.1 to 10% by weight, preferably 1 to 5% by weight 8. Mixtures of an amine-free oxethylate salt, fatty acids and, optionally, ether carboxylic acid and a mineral oil, based on an aqueous solution. 9. Use of amine-free alkyl- or alkenylsuccinic acid salts of alkyl or alkenylsuccinic acid salts of which the alkyl or alkenyl substituents contain 8 to 30 carbon atoms as cooling lubricants or metal processing aids. Use of the compositions according to claims 6 to 8 as cooling lubricants or auxiliary agents in the process