DE1642370A1 - Antifreeze - Google Patents

Description

The invention relates to antifreeze, the new corrosion · «· contain inhibitor systems «,

I "Generally water al" wönaeaua swapping it medium door cooling eye tee by internal combustion engines used "However, since many internal combustion engines temperatures below ⁰ O ALND exposed" are largely ¥ roetochutzmittelgemieohe to Herabaetaung the freezing point of '.Taesere used "This? Roet- Protective agents usually contain, as a means to lower the freezing point, a non-fiber-miscible alcohol, such as methanol or ethylene glycol. Ethylene glycol ₁ Diethylene glycol, dipropylene glycol and other polyhydric alcohols are generally referred to as "permanent" antifreeze agents because they

^109819/0258 "β ana» »·

relatively high boiling point the evaporation of the alcohols from the Cooling system lowers »Water-miscible alcohols with not there are generally more than three carbon atoms in the molecule as a means of lowering the freezing point more effective than Alcohols with higher molecular weights

During normal working conditions, the metallic parts of the cooling system, which contain a wide variety of metals, such as copper, solder, brass, steel, cast iron and aluminum, are subject to corrosion. Therefore, the antifreezes usually contain various compounds that inhibit corrosion the Ver ~ application are gradually consumed and the amount required for an internal combustion engine formed in the system impurities "a Prost retardant is therefore only for a limited time used aur maintenance would be reduced if he had a sealed cooling system ,, J) as _p means that the compounds that are added to the prosthesis protection agent to suppress corrosion should be more effective than the known corrosion inhibitors »

It has now been discovered that an improved corrosion inhibitor system made from a heterocyclic benzo compound (as defined below) and either an alkali metal secondary phosphate or an alkali metal tetraborate with a secondary Alkali metal phosphite or an alkali metal tetraborate with an alkali metal phosphite and an alkali metal phosphate or an alkali metal tetraborate with an illkalimetallaetaborate

1098.1.9 / 02 5.8

BATH ORIGINAL

and an alkali metal phosphate "

The invention therefore relates to an antifreeze based on a water-miscible alcohol, which is characterized by a content of either an secondary alkali metal phosphates or an alkali metal tetraborate and a secondary alkali metal phosphite, or an alkali metal tetraborate and an alkali metal phosphite and an alkali metal phosphate »that of a secondary or a tertiary alkali metal phosphate or a Mixture of the two consists of a heterocyclic benzo compound of the general formula

in which the bensol ring is optionally substituted by at least one alkyl radical and B is a C-SH or C-SM group represents * where M is an alkali metal atom when A is an oxygen atom »a sulfur atom or an NH group» or B represents a nitrogen atom or a CH group »when A is a NH group means »and optionally an antifoam agent ·

The secondary alkali metal phosphate can be, for example, secondary potassium phosphate. Of course, a mixture of a secondary alkali metal phosphate and a tertiary Al-

109819/0258

Potassium metal phosphate in a molar ratio of 1: 1 can be used as secondary alkali metal phosphate, The secondary alkali metal _{phosphate can be prepared in situ by adding the calculated amount of alkali metal hydroxide and phosphoric acid to the water-miscible alcohol 0} If desired, the alkali metal hydroxide and phosphoric acid can be added in aqueous form »

For the production of the anti-freeze agent according to the invention the water-miscible alcohol becomes the heterocyclic alcohol

and/
Benao compound / äem secondary alkali metal phosphate or a primary alkali metal phosphate and a tertiary alkali metal phosphate in a molar ratio of 1: 1 or an alkali metal hydroxide and phosphoric acid in a molar ratio of 2: 1 mixed.

According to a further embodiment of the invention, the antifreeze agent contains the water-miscible alcohol an alkali metal tetraboratej a heterocyclic benzo compound of the formula given and either a secondary alkali metal phosphite or a preferably secondary alkali metal allphoephit and an alkali metal phosphate, which consists of one secondary or a tertiary alkali metal phosphate or a mixture of both

The antifreeze is obtained by mixing the specified compounds ₉ whereby the alkali metal phosphate can be generated in situ by adding the theoretically required amounts of phosphoric acid and alkali metal hydroxide »

. 109819/0258

^; BATH ORIGINAL

According to a further embodiment of the invention, the antifreeze contains, in addition to the water-miscible alcohol, an alkali metal tetraborate, an alkali metal metaborate, an alkali metal phosphate, which consists of a primary or secondary alkali metal phosphate or a semicircle of both, and a heterocyclic benzo compound of the general formula, where the alkali metal tetraborate, the alkali metaborate and the alkali metal _{phosphate are present in such amounts 9} that the pH value of a 50 volume solution of the antifreeze in water, determined according to ASTM method B-1237-58, is not greater than 10.0 and the antifreeze is none Precipitation forms when it stands for one month at room temperature «The antifreeze is obtained by mixing the specified compounds, whereby the alkali metal phosphate can also be prepared in situ by adding the theoretically required amounts of alkali metal hydroxide and phosphoric acid«

Ethylene glycol is preferred as the water-miscible alcohol »

Examples of heterocyclic benzo compounds of the given general formula are 2-mercaptobenzoxazole, 2-mercaptobenathiazole, ^ Ethyl ^ -mercaptobenzthlazol, 2-mercapto-4,5-diuiethylbenzthiazol, Sodium-2-mercaptobenzothiazole, potassium-2-mereäptobenzthiazole, 2-mercaptobenzlmidazole, benzotriazole, 4-methylbenztriazole, 5-methylbenztriazole, benzimidazole 4-methylbenziraidazole, 5-methylbenzimidazole and 5,6-diraethylbenz-

imidazole.

If necessary, the antifreeze can be an antifoam agent contain «Examples of suitable antifoam agents are silicone oils, polyglycols, mineral oils, isooctanol, CU-Cg-oxo alcohols, organic phosphates, alkyl lactates and castor oil soaps » Particularly suitable polyglycols are the polyoxypropylene glycols with a nominal molecular weight of about 950 to 1750, which have been reacted with ethylene oxide to form copolymers, which in the molecule up to etvm JO Garo- # ethylene oxide contain «In general, the amount of antifoam agent is not greater than about 1 Gewa-jS» If desired, the Antifreeze still contain an organic dye "

Particularly suitable antifreeze agents contain 1 to 3.5 wt. secondary potassium phosphate ₉ 0.05 to 0.5 by weight of the heterocyclic benzo compound of the formula given, not more than 1% by weight of an antifoam and the remainder to 100% by weight of monoethylene glycol It has been found that the pH value of a solution of 50% by volume of the antifreeze in water depends on the purity of the secondary potassium phosphate; the pH of the solution is above 9.0 when pure secondary potassium phosphate is used, while it is between about 8.5 and 9.0 when using technical secondary potassium phosphate. The pH of a solution produced with technical secondary potassium phosphate can if desired, by adding small amounts of »aB» about 0.05

109819/0258 bathroom original

up to 0.5 wt .- ^, can be increased by tertiary potassium phosphate » When using technical secondary potassium phosphate should the antifreeze preferably benzstriazole or a Gemlsoh of Beriztriazol with 2-Hercaptobenzthiazol or an alkali « contain nietall-2-mercaptobenzothiazole.

Also particularly suitable are antifreeze agents which do not contain more than 4% by weight of an alkali metal tetraborate, 1 to 3% by weight of a secondary alkali metal phosphate. not more than 1 wt .- # a Antischauramittels, 0.05 to 0.5 wt - $ heterocyclic Benz compound (s) of the formula indicated and the balance up to 100 percent by _e - # contain läonoäthylenglykol, Gewünsentenfalle can antifreeze still 0, 5 to 2.5 wt .- ^ of a secondary alkali metal phosphate and optionally contain enough water to dissolve the alkali metal phosphate. The antifreeze agents expediently contain 0.01 to 0.05 wt .- # of an antifoam agent ο

Furthermore, antifreeze agents are particularly suitable that are not over 0.5 wt. 56 sodium or potassium tetraborate, 0.5 to 2 wt .- ^ ( Sodium or potassium metaborate, 0.5 to 2.5 wt .- ^ secondary Potassium phosphate, optionally enough water to dissolve the secondary potassium phosphate, 0.05 to 0.5% by weight of the heterocyclic Benzo compound (s) of the given general formula, not more than 1 wt .- # of an antifoam agent and the remainder up to Weight - # contain monoethylene glycol, the amounts of sodium or Potassium tetraborate, sodium or potassium metaborate and second

109819/0258

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The potassium phosphate is such that the pH value of a 50% solution of the antifreeze in water does not exceed 10.0 and the antifreeze does not precipitate if it is at room temperature for months swreekmäßig 0.01 to 0 _{t o} 05 percent - and the AnM sehatiiaBLLttels contain "*

It will be understood, that the agents according to the invention are normally added to the water in ae & cooling systems of the internal combustion engines to produce an aqueous solution, 2 »B. 20- to 60- $ ig _f to form «

The invention is explained in more detail by the following examples. In these examples, metal samples, such as are usually found in the cooling systems of internal combustion engines, are kept at a temperature of 82.2 + 1 ° C. for 336 hours in an aqueous solution of the antifreeze agent is blown through the air at a rate of 100 + 10 ml / min o, completely submerged The metal samples used correspond to ASTM test method D 1384-61To The aqueous solution of the antifreeze is obtained by mixing 1 part by volume of the antifreeze with 2 parts by volume of water, which is 0 .01 $> chloride ions (as sodium chloride) and 0.03 $> sulfate ions (as sodium sulfate) contains ₉ manufactured »The corrosive properties of the solution containing the antifreeze is calculated from the weight loss the samples suffer during the test» Each test is carried out three times »Table I gives the 4

1098 19/02 50 BAO original

knew the results obtained from prosthetic agents »From it
it can be seen that the solution of the antifreeze agent according to example A towards tin solder and copper and the solution of antifreeze agent according to example B and example O towards cast iron, steel, aluminum, tin solder and copper are highly corrosive »The solution of the mixture according to example I) has a highly corrosive effect on aluminum »These results can be compared with the values given in Tables II to V.
obtained with the solutions of the antifreeze agents according to the invention. Referred to in the examples 1 to 18 Λ antifoam was a polyoxypropylene glycol having a nominal molecular weight of 1750, the ethylene oxide with a copolymer having a content of about 10 weight "- is reacted # Xthylenoxyd in the molecule. The pH value given in the tables relates to a solution of 50 vol .- # of the antifreeze _{mixture in water p} as determined according to ASTM method D 1287-58 »

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TABEL

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example Antifreeze mixture
Gew, - # Cast iron Weight loss mg / 6, stole aluminum solder 45om ² copper pH 0 0 _P 8 0.1 3.4 Brass 4.9 7.5 Λ Sodium benzoate 5.0 0.3 1.1 0.2 6.2 0.7 5.7 Sodium nitrite 0.5 -0.1 0 0.6 7.3 0.6 1.4 lionoethylene glycol 94.5 404 156 10.6 1.5 0.6 4.6 7.4 B. Sodium tetraborate + * 142 129 9.5 1.5 0.7 14.9 Decahydrate 2 ₉ 7 91 163 8.5 4.1 1.9 14.7 lionoethylene glycol 97.5 1.3 Primary potassium 7.7 27.4 8.2 2.2 2.5 7.3 phosphate 0.4 1.1 C. Sec. Sodium = 4.2 44.2 12.0 4.8 6.7 phosphate '. 0.47 7.8 17.8 17.6 1.9 1.9 1.9 Water 3.6 1.2 Antifoam medium ♦ 0.02 läonoethylene glycol 95.51 Sodium metaborate -0.3 0.5 18.1 Ι, β 1.0 9.4 D. Octahydrate 2.0 0.7 Sodium-2-mercaptQ- 0 0.2 17.2 1.7 1.1 benzthiazole 0.25 0.3 0.1. 16.6 1.4 0.8 1.1 Antifoam 0.02 0.9 Monoethylene glycol 97.73

CO

♦ An olyoxypropylene glycol »χι a nominal molecular weight of 1750, which with ethylene oxide

has been implemented in the molecule ÄthyXejioxyä $ _o - a copolymer with a content of about 10 (* ew "

TABLE II

example Antifreeze mixture C Loss of light ms / 6.45cm stole aluminum solder Brass copper pH • 1 Weight .-? & C black iron -0.2
-0.3
-0.2 0
-0.1
0 -0.1
-0.1
-0.1 0.3
0.1
0 0.2
0.2
0.2 9.2 2 Sec. Potassium phosphate 2.5
Water 2.5
Sodium 2-mereaptobenzothiazole 0.25
Antifoam 0.02
Monoethylene glycol 94.73 -0.8
-0.8
-1.0 0.4
0.2
-0.1 2.3
2.1
1.9 0.9
0.6
0.6 2.2
1.9
2.0 iU
1.4 9.3 λ
m
5 3 Sec. Potassium phosphate 1.0
Tert. Potassium phosphate '1.65
Water 3.0
Sodium 2-mercaptobenzothiazole 0.25
Antifoam 0.02
Monoethylene glycol 94.08 0.3
0
0.3 0.8
0.4
0.8 0.6
0.7
0.6 0.1
0.3
0 0.2
0.3
0.5 0.6
0.7
0.4 9.0 4th üeki potassium phosphate ** 2.5
Tert. Potassium phosphate 0.15
Water 2 * 5
Benzotriazole 0.1
Antifoam 0.02
Monoethylene glycol 94.73 0.3
° o, ₃ 0.4
0.2
0.1 0.7
1.0
0.9 O
-0.1
0.2 1.0
1.2
1.0 1.2
0.4
0.9 8.6 5 Sec. Potassium, pho sphat 2.5
Water 2.5
Sodium 2-mercaptobenzothiazole 0.15
Benzotriazole 0.1
Antifoam 0.02
Monoethylene glycol 94.73 -0.4
-0.4
0.9 0.2
0.3
0.1 0.5
0.7
0.4 -0.1
0
0 1.5
1.4
2.1 1.3
1.5
0.9 8.9
mm
C.
I-
C. Sec. Potassium phosphate 2.5
Water 2.5
Sodium 2-mercaptobenzothiazole 0.25
Antifoam 0.02
Monoethylene glycol 94.73 -0.6
-0.5
0.4

* pure

* ♦ technical

*** in situ by adding potassium hydroxide and phosphoric acid Monoethylene glycol produced.

TABLE III

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example Antifreeze mixture Weight loss mg / 6.45 cm stole aluminum solder Brass copper pH fl Cast iron Sodium tetraborate -0.2 0.5 0 0.1 0.4 7.6 Decahydrate 1.5 -0.3 Seko sodium phosphite 0.1 0.6 -0.3 0.2 0.3 6th Pentahydrate 1.0 -0.6 »0.2 0.9 -0.2 0.3 0.5 Sodium 2-mereaptobenzothiazole 0.25 -0.3 Antifoam 0.02 Monoethylene glycol 97.23 Sodium tetraborate 0.1 0.9 0.1 0.4 0.7 7.5 Decahydrate 1.5 0.2 7th Seko Hodium Phosphite 0.2 0.6 0.3 0.7 0.9 Pentahydrate 1.5 0 0.1 0.8 1.0 0.7 1.0 —Ψ ·
T)
J · » Watriussi-2-mercaptobenzothiazole 0.25 0 Antifoam 0.02 Monoethylene glycol 96.73 Iiatrium tetraborate 0 0.5 -0.1 0.2 0.5 7.6 Decahydrate 1.5 0 Sec. Sodium phosphate 0.2 1.0 -0.1 0.2 0.5 θ Pentahydrate 2.0 -0.7 Sodium-2-mercapto- 0 0.7 0 0.2 0.3 benzthiazole 0.25 0 Antifoam 0.02 Monoethylene glycol 96.73

TABLE IV

example Antifreeze mixture weight loss mg / 6 "45 cm stole aluminum solder Brass copper PH l C. iron ( Sodium tetraborate -0.4 -0.1 0 0.6 0.7 7.7 < Deeahydrate 1.0 -0.5 Sec. Fiatrium phosphate 0.1 -0.2 -0.1 1.1 0.7 Pentahydrate 1.0 -0.8 9 Sec * sodium phosphate -0.1 0 -0.1 0.7 0.6 (pure) 1.0 -0.5 Water «1.0
Sodium enzymecaptobenzothiazole 0.25 AntiFfphaupiPiit + - ?! 0.02 10 Monoethylene glycol 95.75 0 0.5 0 0.9 1.1 7.8 "ι ^V as in example 9, only will «0.5 0.4 0.2 0.1 1.2 1.2 commercial secondary -0.5 0.7 0.5 0.1 1.1 1.9 Tj Potassium phosphate used -0.5 -0.4 -0.1 0 0.6 0.7 7.7 as in example 9, only will -0.5 0.1 -0.2 -0.1 1.1 0.7 ti the secondary potassium phosphate -0.0 0.1 0 -0.1 0.7 0.6 O Addition of potassium hydroxide and -0.5 D. Phosphoric acid to aonoethylene glycol made in situ Sodium tetraborate 0.1 0.4 0.5 1.2 0.8 7.7 Bec & hydrate 1, O -0.1 Sec. Sodium phosphite 0.5 0.2 0.5 1.0 0.7 12th Pentahydrate 1.0 -0.2 0.2 0.1 0.2 1.0 0.8 Sec x potassium phosphate 0.4 0 Tert »potassium phosphate 0.66 t Water 1.5 Sodium-2-fflercaptobenzothiazole 0.25 Q Antifoam 0.02 I. Monoethylene glycol 95.27

AH

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4 » i ® I φ 3 I + · C. * -4 OO Il <? ψ " '3 « p4 O ^. '"tr • Η ft ^ * ¹ ^ I Ρ « • Η SO $ Ή fcß I m ί> <? - ϋ I 0 j H • Η I « be. Φ Si CVJ ei? »t I a .sä & ? Γ " m ι- 09 O O O JD 3 W τ- «- 4 ^s d CD
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S. so? = T H · «" 'Cv ■ β «-» » 4 * «rf M4 » 4 »* tß te ns co Hi r ^ Q "ι ** Φ Φ ctS? J ctt VM φ Φ

; Q9819 / 02Sa

BATH ORIGINAL

1 ABELIiS

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example Prost protection agent mixture C. 0.5 0.02 0.5 0.02 0.02 Weight loss ms / 4.65 cm stole aluminum solder BJe α sing copper pH j 8.4 d Wt .- ^ 95.23 1.0 95.67 ruSeisen M. Sodium tetraborate 1.0 as in example 14, just be 1.5 0.5 -0.1 0.3 0 0.6 0.6 ^l > Decahydrate 1 * 5 instead of sodium mercaptobenzothiazole 1.5 0.5 ~ 0 _B 4 8.4 \ 8.2 Sodium taborate 1.5 0.25 wt. ¹ / »benzimidazole used 0.1 2.0 0 0.2 0.2 0.6 0.7 Octahydrate * Sodium 2-mercaptobenzothiazole 0.25 Sodium tetraborate decahydrate 0.02 2.0 -0.4 0.1 0.5 0.1 1.0 1.0 Seko potassium phosphate Antifoam agents Sodium metaborate octahydrate 95.38 Sodium 2- ⁱ mercaptobenzothiazole 0.25 -0.4 14th V / ater Monoethylene glycol Sec. Potassium phosphate ** 0.5 Antifoam agents water 1.0 Monoethylene glycol Benzotriazole 0.4 'fr * "Tüfr ^ f * Πϊ" 1 * ί_ Pit "! Π Ϊ * Ft ^^ Antifoam agents 0.66 0.7 0.6 0.5 0.3 0.4 8 * 3 Monoethylene glycol 1.5 0.2 0 0.0 1.2 0.2 0.5 15th Sodium tetraborate decahydrate Sodium 2-mercaptobenzothiazole Q 25 -0.2 0.2 0.5. 4.3 0.4 0.7 Sodium metaborate octahydrate Antifoam agents 0.4 0.5 0.4 0.1 0.7 0.2 > Sec ο potassium phosphate Monoethylene glycol -0.3 0.4 0.6 0.1 0.7 0.2 ο ierto potassium phosphate Sodium tetraborate decahydrate 0.4 0.1 0.8 0.3 0.3 0.3 O Y / ater Sodium metaborate octahydrate -0.1 J 16 Seko potassium phosphate * D. water 3.2 0.1 , 0.6 0.4 1.9 0.9 0.2 0.2 0.5 0.3 1.7 1.2 0.2 0.1 0.5 0.3 1.8 17th -0.2 -0.1 0.3 0 0.6 -0.5 0 0 0 0.6 0.4 -0.5 0 0.5 0.1 0.9 0.7 18th -0.2 * T01 KlOtJ

Claims (1)

Claims Antifreeze based on a water-miscible alcohol, characterized by a content of either on a secondary alkali metal phosphate or an alkali metal tetraborate and a secondary alkali metal phosphite, or an alkali metal tetraborate and an alkali metal phos ) hit and an alkali metal phosphate, which consists of a secondary or a tertiary alkali metal! phosphate or consists of a mixture of the two, a heterocyclic benzo compound of the general formula in which the benzene ring is optionally substituted by at least one alkyl group and B represents a G-SH or C-SM group, where M is an alkali metal atom when A is an oxygen atom, a sulfur atom or an NH group, or B is a nitrogen atom or GH-group _r represents when a represents an NH group, and optionally an anti-foaming agent. 2. Froetschutcmittel according to claim 1, characterized in that that it is a secondary alkali metal phosphite as an alkali metal phosphite contains. 10 9 819/0258 BATH ORIGINAL In that it contains antifreeze according to claim 1, characterized in that an alkali metal tetraborate, a Alkaliraetallmetaborat and a primary or secondary Alkaliroetallphosphat, these compounds being present in amounts such that the pH of a LöBimg 50 Yoi "- not # of Frostschutzmittelgemiaohes in water over 10 «0, and the frost protection agent mixture does not form any precipitate, it is allowed to stand for 1 month at room temperature. 4 · Antifreeze agents according to claims 1-3 »characterized by that the alcohol which can be mixed with water is ethylene glycol. 5. Antifreeze according to claims 1-4, characterized in that that it is benzotrlazole as a heterocyclic benzo compound. contains * 6. Antifreeze according to claims 1-4, characterized in that that ea as a heterocyclic compound is 2-meroaptobenzothiasol or contains an alkali metal-2-meroaptobensthlazol » 7 antifreeze agents according to claims 1-6, characterized that it contains benzimidazole as a heterocyclic compound. 8 «Antifreeze according to claim 1, characterized in that that there is 1 to 3.5 wt. 56 secondary potassium phosphate, 0.05 to 0.5 wt .- ^ of the heterocyclic benzo compound, not more than Contains 1% by weight of an anti-foam agent and the remainder of ethylene glycol. 109819/0258 ft 9ο antifreeze according to claim 1, characterized in that that it does not exceed 4 wt .- ^ alkali metal tetraborate >> 1 to 3 wt .- ^ secondary alkali metal phosphite, not more than 1 Wt .- ^ of an antifoam agent, 0.05 to 0.5 fiew .- # der contains heterocyclic benzo compound and the remainder ethyl glycol. 10. Antifreeze according to claim 9 »characterized in that it/ that / 0; 5 to 2.5 wt. 5 »contains secondary alkali metal phosphite» 11. Antifreeze according to claim 1, characterized in " that it does not contain more than 0.5% by weight of sodium or potassium tetraborate, 0.5 to 2 wt .; » Sodium or potassium taborate, 0.5 to 2.5 Wt .- # secondary "potassium phosphate, not more than 1 wt .- ^ of one Antifoam agent, 0.05 to 0.5 wt .- ^ of the heterocyclic Benso compound and the remainder ethylene glycol contains ο ÖAD ORIGINAt 109819/0258