RU2213119C2 - Cooling fluid - Google Patents

Abstract

FIELD: chemical engineering. SUBSTANCE: invention relates to compositions of low-freezing cooling fluids designed for internal combustion engine cooling systems and, as heat carriers, in heat-exchanging apparatuses and temperature-control systems operated at low and moderate temperatures. Cooling fluid contains (i) as base (50.0-97.2%), ethylene glycol or mixture thereof with di-, or triethylene glycol and/or with C1-C2- polyoxyalkylene glycol monoalkyl ethers with average molecular weight 90-120 having general formula:

, wherein R is methyl or ethyl, R₁ methyl or hydrogen, and n=1-9; (ii) as anticorrosive additives (wt %): sodium tetraborate nonahydrate 0.5-8.0; benzotriazole and/or its derivatives, and/or 2-mercaptobenzothiazole sodium or potassium salt 0.05-4.5; acids: boric, adipic, sebacic, benzoic, or triazinotiyl-triiminopolyhexanoic, 2- ethylhexanoic, 2- mercaptobenzothiazolesuccinic, or mixture of these acids 0.1-7.0; and (iii) water, 2.0-49.0%. Fluid may further contain following additional anticorrosive additives, wt %: alkali metal phosphate 0.1-6.0 and/or high-ratio liquid glass and/or Trilon B 0.01-0.5%, and/or dextrin 0.04-0.8, as well as dye (0.001-0.02%) and/or organosilicon foam suppressor (no more than 0.005%). EFFECT: improved anticorrosive properties and increased alkalinity capacity. 2 cl, 3 tbl, 22 ex

Description

 The invention relates to the field of chemical technology, in particular to compositions of low-freezing coolants (coolants) intended for cooling internal combustion engines, as well as used as heat transfer fluids in heat exchangers and thermal control systems operated at low and moderate temperatures.

 To give the coolant the required specific properties, anticorrosion, anti-foaming, coloring and other additives are introduced into their compositions.

 The most common coolants both abroad and on the domestic market are liquids based on aqueous solutions of glycols, mainly ethylene glycol.

 A known composition of the coolant, containing, wt.%: Ethylene glycol 90-95; sodium or potassium tetraborate 0.1-4.0; di- or triethanolamine phosphate 0.1-5.0; sodium salt of 2-mercaptobenzthiazole 0.05-0.5; defoamer 0.0005-0.05; dye and water (the rest) (UK patent 1210370, CL 09/02, publ. 1970).

 The disadvantages of this coolant are its high toxicity, due to the presence in the composition of the amine, instability to hard water and low anticorrosion properties with respect to solder and non-ferrous metals.

 Known coolants based on ethylene glycol or polyglycol containing alkali metal salts of phosphoric acid (4.0-50.0 wt.%), Disodium salt of ethylenediaminetetraacetic acid (0.1-1.0 wt.%), Sodium carbonate (0, 1-2.0 wt.%), Non-ferrous metal inhibitor (0.1-44.0 wt.%), Antifoam (0.1-1.0 wt.%), Dye (0.01-0.5 wt. .%) (RF patent 2125074, publ. 1999; RF application 97107961, publ. 1998). However, this antifreeze is not without a number of disadvantages, such as instability in hard water, due to the high content of phosphates, and high corrosiveness in relation to solder, cast iron.

Known coolant based on ethylene glycol (25-75 wt.%), Containing, wt.%: Sodium tetraborate 0.1-5.0; sodium hydroxide 0.1-5.0; sodium silicate 0.1-5.0; aliphatic monobasic C ₆ -C ₁₂ acids 0.1-5.0; triazole derivatives 0.1-5.0; sodium molybdate 0.1-5.0; water and antifoam (rest) The presence in (US patent 4759864, class C 09 K 5/00, publ. 1988) of antifreeze composition of high concentrations of monobasic aliphatic C ₆ -C ₁₂ acids and sodium metasilicate reduces the antifreeze stability during storage and the formation of sediment In addition, this composition does not improve the anticorrosion properties of known coolants.

Closest to the technical nature of the claimed composition of the coolant is a coolant based on an azeotropic mixture of ethylene glycol and ethylcarbitol, containing, wt.%:
Ethyl Carbitol - 30-76.5
Ethylene glycol - 30-13.5
Sodium tetraborate - 1.0-1.5
Mercaptobenzthiazole - 0.19-0.22
Sodium silicate - 0.001-0.0005
Water - Else
(USSR author's certificate 1658205, class C 09 K 3/18, publ. 1991)
The use of a triple system of ethylene glycol-ethylcarbitol-water can reduce the freezing temperature to -77 ^o With, however, this antifreeze exhibits low anticorrosion properties in relation to steel, aluminum and has a low alkalinity reserve.

 An object of the present invention is to improve the anticorrosive properties of a coolant and increase the alkalinity reserve.

где R - метил (-СН₃) или этил (-С₂H₅);
R₁ - метил (-СН₃) или Н;
n=1-8,
а в качестве антикоррозионных присадок - тетраборат натрия десятиводный, бензотриазол и/или его производные, и/или натриевая или калиевая соль 2-меркаптобензтиазола, и/или гидроксид и/или карбонат щелочного металла, и/или борная, или адипиновая, или себациновая, или бензойная, или триазинотриилтрииминополигексановая, или 2-этилгексановая, или сорбиновая, или 2-меркаптобензотиазоилянтарная кислоты или смесь этих кислот при следующем соотношении компонентов, мас.%:
Этиленгликоль или смесь этиленгликоля с ди-, триэтиленгликолем и/или с моноалкиловыми эфирами (C₁-₂) полиоксиалкиленгликолей средней молекулярной массы 90-210 ед. общей формулы (I) - 50-98
в качестве присадок:
Тетраборат натрия десятиводный - 0,5-8,0
Бензотриазол и/или его производные, и/или натриевая или калиевая соль 2-меркаптобензтиазола - 0,02-2,5
Гидроксид и/или карбонат щелочного металла - 0,05-4,5
Борная, или адипиновая, или себациновая, или бензойная, или триазинотриилтрииминополигексановая, или 2-этилгексановая, или сорбиновая, или 2-меркаптобензотиазоилянтарная кислоты или смесь этих кислот - 0,1-7,0
Вода - 2-50
Кроме того, заявляемая охлаждающая жидкость может дополнительно содержать в качестве антикоррозионных присадок: фосфат щелочного металла 0,1-6,0 мас. %, и/или высокомодульное жидкое стекло и/или трилон Б 0,01-0,5 мас.%, и/или декстрин 0,04-0,8 мас. %, а также краситель в количестве 0,001-0,02 мас. % и/или кремнийорганический пеногаситель в количестве не более 0,005 мас.%
Смесь моноалкиловых эфиров полиоксиэтиленгликоля средней молекулярной массы 90-210 ед. получают методом полиприсоединения оксида этилена, или оксида пропилена, или их смеси к метанолу или этанолу в присутствии щелочного катализатора.The problem is achieved in that the coolant contains a poly (alkylene) glycol base, anti-corrosion additives and water, characterized in that ethylene glycol or a mixture of ethylene glycol with di-, triethylene glycol and / or monoalkyl ethers is used as a poly (alkylene) glycol base C ₁ -C ₂ ) polyoxyalkylene glycols of average molecular weight of 90-210 units. general formula (I)

where R is methyl (—CH ₃ ) or ethyl (—C ₂ H ₅ );
R ₁ is methyl (—CH ₃ ) or H;
n = 1-8,
and as anticorrosion additives, sodium tetraborate, ten-sodium, benzotriazole and / or its derivatives, and / or the sodium or potassium salt of 2-mercaptobenzthiazole, and / or alkali metal hydroxide and / or carbonate, and / or boric, or adipic, or sebacin, or benzoic, or triazinotriyl triiminopolyhexanoic, or 2-ethylhexanoic, or sorbic, or 2-mercaptobenzothiazoyl succinic acid or a mixture of these acids in the following ratio of components, wt.%:
Ethylene glycol or a mixture of ethylene glycol with di-, triethylene glycol and / or monoalkyl ethers (C ₁ - ₂ ) of polyoxyalkylene glycols of average molecular weight of 90-210 units. general formula (I) - 50-98
as additives:
Sodium tetraborate decahydrate - 0.5-8.0
Benzotriazole and / or its derivatives, and / or the sodium or potassium salt of 2-mercaptobenzthiazole - 0.02-2.5
Alkali metal hydroxide and / or carbonate - 0.05-4.5
Boric, or adipic, or sebacic, or benzoic, or triazinotriyl triiminopolyhexanoic, or 2-ethylhexanoic, or sorbic, or 2-mercaptobenzothiazoyl succinic acid or a mixture of these acids - 0.1-7.0
Water - 2-50
In addition, the inventive coolant may additionally contain as anti-corrosion additives: alkali metal phosphate 0.1-6.0 wt. %, and / or high-modulus liquid glass and / or Trilon B 0.01-0.5 wt.%, and / or dextrin 0.04-0.8 wt. %, as well as dye in an amount of 0.001-0.02 wt. % and / or silicone defoamer in an amount of not more than 0.005 wt.%
A mixture of monoalkyl ethers of polyoxyethylene glycol of an average molecular weight of 90-210 units. obtained by polyaddition of ethylene oxide or propylene oxide, or a mixture thereof to methanol or ethanol in the presence of an alkaline catalyst.

Polyaddition of oxides to lower alcohols is carried out in batch or continuous reactors at temperatures above 100 ^o C and under pressure.

 According to the present invention, a mixture of monoalkyl ethers obtained as a by-product in the production of brake fluid can be used as said mixture of monoesters.

The use of such a mixture of monoesters with ethylene glycol or di-, triethylene glycol and water can reduce the freezing temperature to minus 75 ^o C. In addition, typical coolants based on ethylene glycol when boiling water sharply reduce the negative working temperature, since ethylene glycol freezes at minus 13 ^o C. The proposed coolants do not have this drawback. When boiling water, they remain operational, since the mixture of monoalkyl ethers has a freezing point of minus 50-55 ^o C.

 Derivatives of benzotriazole are tolyltriazole, (methyl-1H-benzotriazol-1-yl) methyliminobisethanol.

 Organosilicon liquids, for example, EAP-40, PMS-200 A, etc., are used as antifoam.

 As a dye, alcohol-soluble is used, for example, dye N3 acid bright blue.

 The composition claimed in this invention provides properties that are manifested only in this technical solution, namely: high corrosion stability of the composition relative to structural materials (copper, brass, solder, steel, cast iron, aluminum) while maintaining resistance to hard water and low toxicity, high reserve alkalinity. The high alkalinity reserve of a carefully selected combination of highly effective anti-corrosion additives ensures a longer service life of the coolant.

Preparation of a coolant of this composition is carried out by sequential mixing of the components at a temperature of 40-70 ^o C followed by filtration of the resulting solution.

 Example 1

92.85 g of ethylene glycol is placed in a container and 1.3 g of ten-sodium sodium tetraborate, 2.0 g of a 35% NaOH solution, 1.0 g of triazinotriyl triiminopolyhexanoic acid, 0.7 g of sebacic and 0.5 g of benzoic are gradually dissolved in it. acids, 0.05 g of sodium salt of 2-mercaptobenzthiazole and 0.002 g of dye, 0.1 g of high-modulus water glass with silicate module 2.9 in 2 g of distilled water. The mixture is stirred at a temperature of 50-65 ^o C for 1.5 hours until all components are completely dissolved.

 Table 1 (examples 1-10) presents the compositions of the proposed antifreeze.

Corrosion tests are carried out on 50% solutions according to ASTM D-1384 for 336 hours at 88 ± 1 ^o C with aeration by air.

Example 11
73.89 g of ethylene glycol are placed in a container and 7 g of ten-sodium sodium tetraborate, 23.2 g of a 10% NaOH solution, 5.0 g of 2-mercaptobenzothiazoyl succinic acid, 0.8 g of adipic acid, 0.2 g are gradually dissolved in it. sebacic acid, 1.5 g of benzotriazole and 0.01 g of dye. The mixture is stirred at a temperature of 60-70 ^o C for 1.5 hours until all components are completely dissolved.

 From the obtained concentrated composition of additives and similar ones shown in table 1 (examples 11-19, 21), antifreeze samples are prepared for testing for corrosion activity by diluting it with ethylene glycol in a ratio of 1: 5 to 1: 6.

Corrosion tests are carried out on 50% solutions according to ASTM D-1384 for 336 hours at 88 ± 1 ^o With aeration with air
Comparative results of corrosion testing of samples according to the invention and the prototype are shown in table 2.

The prepared compositions are tested for resistance to hard water according to GOST 28084-89. To do this, they are diluted in a volume ratio of 1: 1 with hard water with a salt content, mg / l:
Calcium Chloride - 275
Sodium Sulfate - 148
Sodium Chloride - 165
Sodium Carbonate - 138
heated to 88 ± 2 ^o C and left for 24 hours in a dark place. As a control sample, a 50% solution of antifreeze in distilled water is tested. The criterion for the resistance of antifreeze to hard water is the absence of sediment and separation of the liquid phase. Other formulations are prepared similarly.

 The determination of the alkalinity reserve is carried out according to the method of ASTM-1121. The pH value is measured in 50% solutions of antifreeze samples according to ASTM-1287.

 As can be seen from tables 1 and 2, the compositions 1-4 and 11-14 have a fairly high anti-corrosion properties.

 With a decrease in the concentration of sodium tetraborate less than 0.5 wt.%, The corrosion of ferrous metals increases (example 5), an increase in its content of more than 8.0 wt. % does not improve the protective properties of the composition (example 15) and causes it to precipitate, which can cause clogging of the radiator.

 A decrease in the content of the sodium salt of triazinotriyl triiminopolyhexanoic acid of less than 0.1 wt.% Leads to an increase in the corrosion effect on the solder (example 6), and an increase in its content of more than 7.0 wt.% Is impractical, since it does not affect the corrosive properties of the liquid (example 16 )

 The decrease in the sodium salt of 2-mercaptobenzthiazole less than 0.02 wt. % causes rubber swelling and corrosion of non-ferrous metals increases (example 7), and with an increase in its content more than 2.5 wt.% the protective properties do not improve (example 17).

 When the content of benzotriazole or its derivatives is less than 0.02 wt.%, The corrosion of non-ferrous metals is enhanced (example 8), and an increase in its content of more than 2.5 wt.% Does not increase the positive effect (example 18).

 A decrease in the content of high-modulus liquid glass of less than 0.02 wt.% Causes an increase in the corrosive effect of the liquid on aluminum (Example 9), and an increase in its content of more than 0.5 wt.% Is undesirable, since it increases the density and viscosity of the coolant and promotes the formation of sol, which will worsen heat transfer processes in the radiator.

 A decrease in water content of less than 2.0 wt.% Causes glazing of sodium metasilicate and precipitation of salts, and an increase in its content of more than 50 wt.% Leads to a decrease and non-compliance with the requirements of GOST 28084-89 temperature characteristics.

 A decrease in dye content of less than 0.001 wt.% Weakens the color intensity of the coolant, which reduces the possibility of quick control of leakage of the cooling system, and an increase in dye content of more than 0.02 wt.% Is not economically feasible.

 The concentration limits of alkali metal hydroxide and carbonate determine the optimal pH range of the coolant composition. An increase in the content of Trilon B above the upper limit leads to a decrease in the corrosion resistance of non-ferrous metals (Example 19), and a decrease in its concentration below 0.01 wt.% Causes precipitation upon dilution with hard water (Example 10). Trilon B is added to the coolant only if disodium or dipotassium phosphates are used in the additive system.

 A decrease in the concentration of alkali metal phosphate enhances the corrosion of ferrous metals (example 21), and when its concentration exceeds the upper limits, the positive effect is not enhanced (example 22).

 Thus, coolants obtained on the basis of poly (alkylene) glycols and anticorrosion additives have high protective properties with respect to structural materials of internal combustion engines, are resistant to hard water, have a high alkalinity reserve and low toxicity.

Claims (1)

1. The cooling liquid containing poly (alkylene) glycol-based, anticorrosive additives and water, characterized in that the poly (alkylene) glycol-based, ethylene glycol is used or a mixture of ethylene glycol di-, triethylene glycol and / or a mono-alkyl esters (C ₁ - With ₂ ) polyoxyalkylene glycols of an average molecular weight of 90-210 units. general formula (I)

where R is methyl (—CH ₃ ) or ethyl (—C ₂ H ₅ );
R ₁ is methyl (—CH ₃ ) or H;
n = 1-8,
and as anticorrosion additives, sodium tetraborate, ten-water sodium, benzotriazole and / or its derivatives, and / or sodium or potassium salt of 2-mercaptobenzthiazole, and / or alkali metal hydroxide and / or carbonate, and / or boric, or adipic, or sebacin or benzoic or triazinotriyl triiminopolyhexanoic, or 2-ethylhexanoic, or sorbic, or 2-mercaptobenzothiazoyl succinic acid, or a mixture of these acids, in the following ratio, wt. %:
Ethylene glycol or a mixture of ethylene glycol with di-, triethylene glycol and / or monoalkyl ethers (C ₁ -C ₂ ) of polyoxyalkylene glycols of average molecular weight 90-210 of the general formula (I) - 50.0-97.2
as additives:
Sodium tetraborate decahydrate - 0.5-8.0
Benzotriazole and / or its derivatives, and / or the sodium or potassium salt of 2-mercaptobenzthiazole - 0.02-2.5
Alkali metal hydroxide and / or carbonate - 0.05-4.5
Boric, or adipic, or sebacic, or benzoic, or triazinotriyl triimino-polyhexanoic, or 2-ethylhexanoic, or sorbic, or 2-mercaptobenzothiazoyl succinic acid, or a mixture of these acids - 0.1-7.0
Water - 2.0-49.0
2. The cooling fluid according to claim 1, characterized in that it may additionally contain as anticorrosion additives: alkali metal phosphate 0.1-6.0 wt. %, and / or high modulus liquid glass, and / or Trilon B 0.01-0.5 wt. %, and / or dextrin 0.04-0.8 wt. %, as well as dye in an amount of 0.001-0.02 wt. %, and / or silicone defoamer in an amount of not more than 0.005 wt. %

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