DE2429512A1 - CORROSION INHIBITION - Google Patents

Description

Ceramic surfaces are often chemical and electrochemical Exposed to attacks that destroy these surfaces. One can prevent this corrosion on the metal surface with benzotriazole or tetrahydrobenzotriazole a monouolecular one Build up a chelate complex layer that adheres very firmly, chemically is inert and thus removes the metal surface from corrosive water flows.

Ir. In practice, one is usually faced with the problem of protecting machine parts that are related to lubricants, e.g. bearing shell, g ^ .g'en the corrosive effect of the lubricant ( e.g. active sulfur compounds in lubricating oil): n Dissolve the benzotriazole in the lubricant. This is very difficult, however, because benzotriazole dissolves in mineral oil in a practically acceptable time only at higher temperatures, and then only in small amounts. Tetrahydrobenzotriazcl also has a corrosion-inhibiting effect, is slightly more soluble, but here, too, dissolving and mixing into an oil is extremely difficult and time-consuming.

Some of these difficulties can be avoided by using thiodiazple as corrosion inhibitors. These products are liquid at 20 ⁰ C, can be easily in oil interfere s'ind'aber considerably less h / irksam as benzotriazole.

_ A -

RCR 116

509882/0841

The object of the invention is therefore a liquid corrosion agent to make available on a benzotriazole basis can be easily incorporated into lubricant.

The invention accordingly provides a corrosion protection agent for metal surfaces, consisting of a solution of benzotriazole and / or tetrahydrobenzotriazole in an amine salt of a carboxylic acid, an amine salt of a phosphoric acid, a phosphorus acid trialkyl ester, an amine alkylbenzenesulfonate or Mixtures of these, the additional free amines, free carboxylic acid or phosphoric acid mono- or di-esters.

These solutions have a number of unexpected advantages. Benzotriazole or tetrahydrobenzotriazole is easily soluble (up to 40%) in the solvents mentioned, even at room temperature (20 ° C.). The solutions are liquid. They can be incorporated into lubricants at room temperature. Here, too, the solvent acts as a solubilizer and increases the solubility of the benzotriazole or tetrahydrobenzotriazole in oil considerably (about 9 times). At the same time, the solvent also increases the corrosion-inhibiting effect of the benzotriazole, so that a considerably reduced amount is sufficient for the same effect.

The anti-corrosion agent of the invention is particularly effective against the corrosion of non-ferrous metals such as copper and copper alloys by sulfur compounds such as active sulfur-containing lubricating oil additives. That is why it is preferred for this one Purpose used.

Solvents for benzotriazole or tetrahydrobenzotriazole in the context of the invention

RCR 116 - 2 -

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change j

naohträi? A2 B 5 1

geä j

1) Amine salts of carboxylic acids

The carboxylic acids on which the salts are based are in particular aliphatic monocarboxylic acids with 6-18 carbon atoms. Saturated aliphatic monocarboxylic acids having 6-10 carbon atoms and unsaturated ones are particularly preferred aliphatic monocarboxylic acids with 6-14 carbon atoms.

The amines on which the salts are based are aliphatic, cycloaliphatic and aromatic mono-, di- and triamines. Mono-, di- and trialkylamines whose alkyl groups contain a total of 6-18 carbon atoms are particularly preferred.

In addition to these salts, there may also be an excess of the acid, the amine: acid molar ratio preferably 1: does not exceed.

Examples of suitable carboxylic acids are caproic acid, capric acid, Isononanoic acid, isopalinitic acid, oleic acid.

Examples of suitable amines are n-hexylamine, tert.-octylamine, tert-isotetradecylamine, oleylamine, dicyclohexylamine, aniline.

2) amine salts of phosphoric acids

The same amines that are used to form the carboxylic acid salts are suitable here. Phosphoric acids are phosphoric acid themselves or their mono- and dialkyl esters. A neutral salt is preferably formed from these phosphoric acids, i. all acidic hydrogen atoms present are converted. An excess of phosphoric acid is also possible here.

Salts of alkylamines and phosphoric acids or their mono- or dialkyl esters are particularly preferred. .In these salts the total number of carbon atoms in all alkyl groups is preferably 10-40. Examples of suitable compounds are Mono-butyl phosphate, di-butyl phosphate, di-2-ethylhexyl phosphate, Monooctadecenyl phosphate.

* 3 RCR 116

S09882 / 0841

IMSPECTED

3) Trialkyl phosphorate, optionally in a mixture with one of the amines mentioned under (1). The molar ratio of phosphoric acid ester : Amin should not exceed 1: 1. Phosphoric acid trialkyl esters preferably contain a total of 10-40 carbon atoms in the alkyl groups.

Examples of suitable phosphoric acid esters are tributyl phosphate, tri-2-ethylhexyl phosphate, tridodecyl phosphate and dibutyl-2-ethylhexyl phosphate.

4) Amine-alkylbenzenesulfonates are preferably salts of the below (1) named amines with alkylbenzenesulfonic acids containing 1-18 carbon atoms in the alkyl group.

Examples are p-toluenesulfonic acid, isooctadecenylbenzenesulfonic acid.

It is possible to use any combination of these solvents.

All of these solvents dissolve benzotriazole and tetrahydrobenzotriazole to very concentrated solutions at room temperature. These solutions can also easily be used at room temperature be incorporated into the lubricant. In particular, they are added to mineral lubricating oils, which are corrosive Contain ingredients, e.g. active sulfur compounds. In the lubricating oil it is usually sufficient a concentration of the benzotriazole or tetrahydrobenzotriazole from 0.01 to 0.1% by weight to prevent corrosion of copper or copper compounds, that are in contact with the oil. This concentration is considerably lower than that in the absence of the solvent required for the same effect. Because the oil is a liquid corrosion inhibitor are added, the solvent of which increases the solubility of the benzotriazoles or tetrahydrobenzotriazoles in the If the oil increases, there is also no risk of segregation.

RCR 116 - 4 -

509882/0841

In principle, any lubricant can be given a corrosion-inhibiting finish in this way. Examples of particularly suitable lubricants are mineral oils on a paraffinic, naphthenic, aromatic or mixed basis with the usual viscosities of 1.2 - 20 ° E at 50 ⁰ C, synthetic oils, e.g. ester oils, alkylbenzenes and their mixtures with mineral oils, lubricating greases, e.g. lithium greases, Calcium fats.

RCR 116 . - 5 -

509882/0841

242951

subsequently changed

example 1

1) Benzotriazole solution:

400 g iso ^ onanoic acid and 250 g isododecylamine are under Mixing stirring and cooling. 350 g of benzotriazole are slowly dissolved in this mixture and the solution is filtered. It a 35% benzotriazole solution is obtained.

2) solubility in mineral oil

In each 100 g of paraffin-based spindle oil are ^{stirred at 22 0} C:

(A) 10 mg of the solution according to (1)

(B) 30 mg of the solution according to (1)

(C) 10 mg benzotriazole

(D) 10 mg tetrahydrobenzotriazole

(E) 10 mg thiadiazole

The lubricating oils obtained in this way contain:

(A) _0/0 03 _X wt .-% benzotriazole (B) C ₍₀ <1 wt .-% of benzotriazole

Wt% benzotriazole

Wt -.% Tetrahydrobenzotriazole (E) O O ₁ -I _x wt .-% thiadiazole

During production, lubricating oils A, B and E were completely clear after one minute, while with C and D the additive had not yet dissolved even after one hour. In C the additive only dissolved when heated to 70 ^° C., in D when heated to 50 ^° C.

But 0.3% (0.1 wt .- # benzotriazole equivalent) of the solution% benzotriazole, according to (1) - in the same lubricating oil 00:02 wt dissolved at 22 ° C..

RCR 116 - 6 -

509882/0841

3) Corrosion test:

1.) Cu activity according to ASTM-D-130

The test was carried out in a commercially available paraffinic mineral oil with a viscosity of 1.5 ^° E at 50 ^° C.

In this oil, 0.5% thiononylphenyl polysulfide was dissolved with 38 % total sulfur and 26 % active sulfur.

To 100 ml each of this solution were then

a) 30 mg Berizotriazol stirred at 90 ⁰ C in half an hour,

b) 30 mg of product from Example 1 are incorporated at 25 ° C. in 10 minutes

stirs.

These solutions were then tested together with a sample c) = without the addition of corrosion inhibitors according to ASTM-D-130 in the Cu strip test checked. Here, 1a means no corrosion, 4c means severe corrosion.

Solution Cu activity according to ASTM-D-130 at 130 ⁰ C in

2.) V-W-RingrJHentest according to W-P-1401

Testing was carried out again in a commercially available paraffinic

Mineral oil having a viscosity yon 1.5 ⁰ E at 5O ⁰ C.

In every 100 g of this oil were 0.9 g of zinc dialkyldithiophosphate, and

a) 30 mg benzotriazole

b) 30 mg of product from Example 1

stirred in and dissolved and emulsified in 2 g of water.

RCR 116 - 1 -

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3 hours 5 hours 3a 3a 1a - 1b 1b 4c 4c

3b Flat grate 3b Rust spots 4a Surface grate

These emulsions were tested together with a sample c) = without corrosion protection according to VW-P-1401. The evaluation takes place by Cu according to ASTM-D-130, see above, for iron, rust-free, rust spots, surface rust.

Solution Corrosion after 48 hours / 100 ° C

Cu Fe

Examples 2-29:

Using the method of Example 1, the solubility of the benzotriazole in these was determined using various solvents Solvents, the solubility of the solutions obtained in lubricating oils and the effect of these lubricating oils against corrosion checked by copper. The results are shown in Table 1.

The following lubricating oil was used:

Example 1-23 a paraffin-based spindle oil with a 28-30 viscosity of 1.5 ^° E at 50 ^° C. = 6.0 cSt

Examples 24-25 a paraffin-based gear oil with a

Viscosity of 122.6 cSt at 50 ^° C

Examples 26-27 a naphthenic spindle oil with a

Viscosity of 8.22 cSt at 50 ^° C

Example 31 Synthetic oil alkylbenzene with a viscosity

of 17.2 cSt at 5O ⁰ C

Example 32 synthetic oil, commercially available ester oil on sebum

zinsäurebasis having a viscosity of 12.1 cSt at 50 ⁰ C

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Table 1

12 3/4 5 6 7

No. Solvent Molver- Benzotria- solution (4) Benzo- Increase in the

ratio of zol dissolved in oil triazole sensitivity to

%% In oil over pure benzo

% triazole by factor

Corrosion protection effect for copper

Octadecyl phosphate

Di-2-ethylhexylphosphate

Tri-2-ethylhexylphosphate

Tri-n-butyl phosphate

p-toluenesulfonic acid + i-tetradecylamine

i-octadecenylbenzenesulfonic acid + t-octylamine

n-caproic acid + dicy ohexylamine

1 :

1 :

35 0.3 0.105 5.25 35 0.3 0.105 5.25 25th Oo 35 0.088 4.4 35 0.3 0.105 5o25

1: 0.5

0.1

O0I5

0.25

0.04

0.037

0.1

2.0

1.87

Table 1

3 4 5 6 7

No. Solvent Molver- Benzotria- solution (4) Benzo- Increase in the

ratio of zol dissolved in oil triazole sensitivity to

%% In oil over pure benzo

% triazole by factor

Corrosion protection effect for copper

cn
ο I. 9 n-lauric acid
+ Dicyclohexyl-
amine 1 : 0.5 40 0.3 0.12 6th 00
CD O
I. 10 Caproic acid +
t-isooctylamine 1 : 0.5 40 Oo2 0.08 4th ! / 08 11 Lauric acid +
t-iso-octylamine 1 : 0.5 30th 0.2 0.06 3 Ü 12th Caproic acid +
n-hexylamine 1 : 0.5 35 Oo3 0.105 5.25 13th Valerionic acid
+ tert-iso-
tetradecylamine 1 : 0o5 40 0.15 0.06 3

14 caproic acid + tert-iso-tetradecylamine 1

15 lauric acid + tert-iso-tetradecylamine 1

16 isononanoic acid + tert-iso-tetradecylamine 1

: 0.5 40

: 0.5 30

: 0.5 35

0.12 0.09 0 _o 105

4.5

5.25

-t-

σ \

Tabel

1 2 3 4 5 6 7

No. Solvent Molver- Benzotria- solution (4) Benzo- Increase in the

ratio of zol dissolved in oil triazole sensitivity to

%% In oil over pure benzo

% triazole by factor

Corrosion protection effect for copper

an ο to oo

17th Isononanoic acid 1 : 1 30 + t-iso-tetra- decylamine 18th mono-η-butyl phosphate + di- n-butylphosphate 0 .3: 0.3: 0.4 + tert-iso- 40 tetradecylamine 19th Tributylphosphere phat + terto- 0 .9: 0.1 30 Iso-tetradecyl- amine 20th Tr ibutylpho s - phat + tert, - .9 : 0.1 40 Iso-tetrad cylamine 0

21 tributyl phosphate + tert, -iso-tetradecylamine 0.7: 0 "3rd

0.3

0.2

0.5 0.6

0.09

0.08

0o15

0.18

4.5

7.5

Table 1

12 3 4 5 6 7

No. Solvent Molver- Benzotria- Solution (4) Benzo- Increase in the LÖ-

ratio of zol dissolved in oil triazole sensitivity to

%% In oil over pure benzo

% triazole by factor

Corrosion protection for copper

cn
ο
co

Tributyl phosphate + terto-iso-tetradecyl-

amine 0 »7: 0.3

Tributyl phosphate + tert, -Iso-tetradecyl-

amine 0.7: 0..3

Tributylpho sphat + terto-iso-tetradecyl-

amine 0.7: 0.3

Tributyl phosphate + tert-iso-tetradecyl-

amine 0.7: 0.3

Tributyl phosphate + tert-iso-tetradecyl-

amine 0 "7: 0.3

0o12

0.075

0.24

0.15

Table 1

PO

12 3 4 5 6 7

No. Solvent Molver- Benzotria- solution (4) Benzo- Increase in the

ratio of zol dissolved in oil triazole sensitivity to

%% In oil over pure benzo

% triazole by factor

Corrosion protection effect
for copper

27

28

29

30th

Tributyl phosphate + tert-iso-tetradecylamine

0.3

Tributyl phosphate + isononanoic acids Q 70: o ₍ 30

Tributylphosphate + tert, -iso-tetradecylamine + Isononanoic acid

:

Tributyl phosphate + tert _o -isotetradecylamine + isononanoic acid

0.25

30th

0.6 30

i 0.45 30

0 _o 10

0.12

Oo12

0.09

4.5

3 O
0
BB eight D. SB (5 3. O

fs) CD

ίο Table 1

^ 12 34 56 7

No. Solvent Molver- Benzotria- solution (4) Benzo- Increase in the dissolving corrosion

ratio of zol dissolved in oil triazole Liability counter-protective effect

%% In oil over pure copper benzo

% triazole by factor

31 tributylphosphere

J "phat + tert.-

S iso-tetradecyl-

O ₀ amine 0.7: 0.3 40 0.4 0.16

K) 32 tributylphos- in each

* <s phat + tert.- dem

O iso-tetradecyl ratio

00 amin 0.7: 0.3 40 nis -4 40 %

* "* ^ L mixed-

"* . bar

Claims (15)

Claims ; i'1J Corrosion protection agent for metal surfaces, consisting of a solution of benzotriazole and / or tetrahydrobenzotriazole in an amine salt of a carboxylic acid, an amine salt of a phosphoric acid, a phosphoric acid trialkyl ester, an amine alkylbenzenesulfonate or mixtures thereof as a solvent. 2. Corrosion protection agent according to claim 1, characterized in that that an amine salt of a carboxylic acid is used as the solvent which contains an excess of free carboxylic acid. 3. Corrosion protection agent according to claim 1, characterized in that that an amine salt of a phosphoric acid is used as the solvent which contains an excess of phosphoric acid mono- or -dialkyl ester. 4. Corrosion protection agent according to claim 1, characterized in that that a phosphoric acid trialkyl ester is used as a solvent in a mixture with an amine. 5. Corrosion protection agent according to claim 1, characterized in that that the solvent used is an amine-alkylbenzenesulfonate which contains an excess of free amine " 6. Corrosion-inhibiting lubricant, characterized by the addition of a solution of benzotriazole and / or tetrahydrobenzotriazole in an amine salt of a carboxylic acid, an amine salt of a phosphoric acid, a phosphoric acid trialkyl ester, an amine-alkylbenzenesulfonate or mixtures thereof as a solvent. 7. Corrosion-inhibiting lubricant according to claim 6, characterized characterized in that an amine salt of a carboxylic acid is used as the solvent, which has an excess of free carboxylic acid contains. RCR 116 - 15 - 509882/0841 8. Corrosion-inhibiting lubricant according to claim 6, characterized characterized in that an amine salt of a phosphoric acid is used as the solvent, which contains an excess of phosphoric acid mono- or dialkyl ester. 9 ο Corrosion-inhibiting lubricant according to claim 6, characterized in that a phosphoric acid trialkyl ester mixed with an amine is used as the solvent. 10. Corrosion-inhibiting lubricant according to claim 6, characterized in that an amine-alkylbenzenesulfonate is used as the solvent is used which contains an excess of amine. 11. Processes to reduce the corrosion of metal surfaces, characterized in that metal surfaces with a solution of benzotriazole and / or tetrahydrobenzotriazole in an amine salt of a carboxylic acid, an amine salt of a phosphoric acid, a phosphoric acid trialkyl ester, an amine alkylbenzenesulfonate or mixtures thereof as a solvent in contact, the solution optionally containing a lubricant is added. 12. The method according to claim 11, characterized in that an amine salt of a carboxylic acid is used as the solvent, which contains an excess of free carboxylic acid. 13. The method according to claim 11, characterized in that an amine salt of a phosphoric acid is used as the solvent, which contains an excess of phosphoric acid mono- or dialkyl ester. 14. The method according to claim 11, characterized in that a phosphoric acid trialkyl ester in a mixture with an amine is used. RCR 116 - 16 - 509882/0841 15. The method according to claim 11 ,. characterized in that an amine-alkylbenzenesulfonate is used as the solvent, the contained an excess of amine RCR 116 - 17 -