RU2370512C1 - Cooling liquid - Google Patents

Abstract

FIELD: chemistry.

SUBSTANCE: cooling liquid contains, wt %: sodium nitrite 0.1-0.2, sodium nitrate 0.2-0.3, benzotriazole 1.0-2.0, ethanolamine borate 2.0-3.0, ethyleneglycol 50.0-60.0 and water - the rest.

EFFECT: improved protective properties of the liquid towards steel, cast-iron and aluminium.

1 cl, 4 tbl

Description

The invention relates to low-freezing coolants and can be used to cool internal combustion engines (ICE) of automobiles, agricultural machinery, special equipment, and also as a coolant in heat exchangers.

The liquids used in the cooling system of the internal combustion engine of automotive vehicles are subject to stringent requirements for the lower limit of the operating temperature, as well as for the corrosive and chemical effects on metal and rubber engine parts.

Known coolant, including, wt.%: Ethylene glycol 93.0-93.5, alkali metal benzoate 2.90-3.10, alkali metal salicylate 0.08-0.12, alkali metal hydroxide 0.20-0, 30, sodium tetraborate (anhydrous) 0.65-0.75, cyclohexanone 0.28-0.32, alkali metal salt of 2-mercaptobenzthiazole 0.01-0.02, benzotriazole 0.27-0.28, N-benzylidenecyclohexylamine 0.28-0.32, alkali metal nitrite 0.15-0.20, silicone defoamer 0.02-0.03, dye 0.0015-0.035 and the rest of the water (RU 2050396 C1, class C09K 5/10, C23F 11/12, 11/14, 12.20.1995).

The disadvantage of this coolant is a multicomponent complex composition, including 9 anti-corrosion additives with a total content of 4.82 to 5.41 wt.%, Which greatly complicates the technology for producing coolant.

The closest analogue of the proposed technical solution is a coolant, including, wt.%: Sodium nitrite 0.1-0.2, sodium nitrate 0.1-0.2, sodium benzoate 0.5-5.0, sodium tetraborate 0, 1-0.5, hexamethylenediamine phosphate 0.1-5.0, benzotriazole 0.20 or 2-mercaptobenzthiazole sodium salt (captax) 0.80-0.95, ethylene glycol 79.8-98.1 and the rest water. If necessary, antifoam and dye are introduced into the composition of the coolant. (UK application No. 1397792, class C09K 5/00, 06/18/1975).

The disadvantage of this composition is that it is quite aggressive towards ferrous metals and aluminum.

The technical result of the invention is to increase the protective properties of the liquid with respect to steel, cast iron and aluminum.

This result is achieved in that the coolant, including sodium nitrite, sodium nitrate, benzotriazole, ethylene glycol and water, additionally contains ethanolamine borate in the following ratio, wt.%:

Sodium nitrite 0.1-0.2 Sodium nitrate 0.2-0.3 Benzotriazole 1.0-2.0 Ethanolamine Borate 2.0-3.0 Ethylene glycol 50.0-60.0 Water rest

A distinctive feature of the proposed technical solution is that the introduction of ethanolamine into the borate at the stated ratio of the components allows to obtain a coolant with high protective properties with respect to ferrous and non-ferrous metals.

Atanolamine borates (BEAs) are the products of the reaction of boric acid with mono-, di- or triethanolamine. Monoethanolamine borate (BMEA) is prepared according to the following scheme:

H ₂ NCH ₂ CH ₂ OH + H ₃ BO ₃ → H ₂ NCH ₂ CH ₂ OB (OH) ₂

Diethanolamine borate (BDEA) is prepared according to the scheme:

HN (CH ₂ CH ₂ OH) ₂ + H ₃ BO ₃ → HN (CH ₂ CH ₂ O) ₂ BOH

Triethanolamine borate (BTEA) is prepared according to the scheme:

N (CH ₂ CH ₂ OH) ₃ + H ₃ BO ₃ → N (CH ₂ CH ₂ O) ₃ V

The introduction of BEA in the composition of the coolant in an amount of less than 2.0 wt.% Does not significantly increase the anticorrosive properties of the fluid with respect to ferrous metals. The introduction of BEA in an amount of more than 3.0 wt.% Is impractical, since there is no further increase in protective properties.

The technology for obtaining BEA is as follows:

In a flask equipped with a mechanical stirrer, a thermometer and a Dean-Stark nozzle, 2 moles of EA (121 g of MEA, 210 g of DEA or 298 g of TEA) are loaded. After heating the EA to 100-110 ° C, 62 g (1 mol) of boric acid is introduced into the flask and a condensation reaction is carried out at a temperature of 160-180 ° C until the water evolution ceases. After cooling to 70-80 ° C, 132 g of water are added to the resulting product. Ethanolamines borates are clear, light yellow solutions with a pH of 10-11 and an amine number of 185-195 mg Hcl / g.

Benzotriazole - 1,2,3 formulas C ₆ H ₅ N ₃ (TU 6-09-1291-87) is a white crystalline powder with a pink, cream or yellowish tint, melting point 96-99 ° C, mass fraction of volatile substances not more than 0.15%.

The technology for preparing the coolant is as follows.

The calculated quantities of water (softened), sodium nitrite and sodium nitrate, BEA obtained as described above, and benzotriazole are successively loaded into a container with a stirrer. After stirring for 10-15 minutes, ethylene glycol is added to the resulting aqueous solution, and the mixing process is continued for another 30-40 minutes. If necessary, any neutral dyes can be added to the coolant, in particular Na-fluorescein for light green color and others.

The compositions of the samples of the proposed coolant are presented in table 1.

Tests of liquids for corrosion on metals at 88 ± 2 ° С for 336 h were carried out according to the methods described in GOST 28084-89, which are in full accordance with ASTM methods.

The results of corrosion tests of the compositions of the proposed coolant in comparison with the composition of the prototype are presented in table.2.

Tests of rubber for swelling in the proposed liquid was carried out according to GOST 9.030 at a temperature of 100 ° C for 70 hours

The results of the rubber test for swelling in coolants are given in table.3.

The main physico-chemical properties of the proposed coolant are given in table 4.

The use of the proposed coolant in internal combustion engines of automotive, agricultural and special equipment will protect components and components of internal combustion engines made of ferrous and non-ferrous metals from corrosion damage.

Table 1
The compositions of the proposed coolant Components The content of the components according to the examples, wt.% one 2 3 four 5 Sodium nitrite 0.10 0.15 0.20 0.05 0.25 Sodium nitrate 0.20 0.25 0.30 0.15 0.35 Benzotriazole 1,0 1,5 2.0 0.5 2.5 BMEA 3.0 - - - 3,5 BDEA - 2.5 - 1,5 - BTEA - - 2.0 - - Ethylene glycol 60.0 55.0 50,0 45.0 65.0 Water 35.7 40.6 45.5 52.7 28,4

table 2
Results of corrosion tests of coolants Compositions of coolants Material copper brass solder cast iron steel aluminum weight loss, g / m ² . day Example 1 0.02 0,03 0.04 0.02 0.01 0.04 Example 2 0.01 0.02 0,03 0.01 0.008 0.02 Example 3 0.02 0.02 0.04 0,03 0.02 0,03 Example 4 0.05 0.04 0.06 0.08 0,07 0.08 Example 5 0.04 0.04 0.05 0.05 0.05 0.06 Prototype 0.05 0.04 0.06 0.1 0.09 0.08 Requirements GOST 28084-89 no more than 0.1 no more than 0.1 no more than 0.2 no more than 0.1 no more than 0.1 no more than 0.1

Table 3
Coolant swelling rubber test results Indicators The value of the indicator for example Prototype GOST norm one 2 3 four 5 Rubber swelling,%:
standard samples of rubber brand 57-5006
standard samples of rubber brand 57-7011 no more 1.4 1,2 1.3 2.0 1.7 3,5 5 no more 0.9 0.7 0.8 1,5 1,2 2.7 5

Table 4
The main physico-chemical properties of the proposed coolant Indicator BMEA Coolant Coolant with BDEA BTEA coolant Density at 20 ° C, g / cm ³ 1,068 1,070 1,074 Boiling point at a pressure of 110.3 kPa (760 mm Hg), ° С 108,5 110 112.5 Hydrogen index (pH) at a temperature of 20 ° C 10.3 10.0 9.01 Alkalinity reserve, cm ³ 23.8 23.6 20.8 The temperature of the onset of crystallization, ° C -40 -44 -45

Claims (1)

Coolant, including sodium nitrite, sodium nitrate, benzotriazole, ethylene glycol and water, characterized in that it additionally contains ethanolamine borate in the following ratio, wt.%:
Sodium nitrite 0.1-0.2 Sodium nitrate 0.2-0.3 Benzotriazole 1.0-2.0 Ethanolamine Borate 2.0-3.0 Ethylene glycol 50.0-60.0 Water rest