JPH0437810B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to gelation-resistant aqueous glycol or glycol ether compositions containing phosphorus-modified silanes. Antifreeze compositions containing glycols and various corrosion inhibitors have been described in the prior art, e.g.
Ordelt U.S. Patent No. 3,362, issued on May 9,
No. 910. These patents detail the relatively inexpensive and effective use of borax and silicates in the formulation of glycols.
In this technology, a concentrated composition of glycol is typically produced and sold to the end user for dilution with water and injection into the radiator of an automobile as a coolant. In the past, glycol-rich compositions using common corrosion inhibitors such as borax and silicates were known to have a tendency to form irreversible silicate gels when left in warehouses or shops for periods of time. . When an end user injects a glycol-rich composition into an automobile radiator, the concentrated composition may form slugs or gels that do not allow for easy injection or result in liquid and lumps being thrown out.
The present invention was developed to eliminate this gel formation. Wilson, U.S. Pat. No. 4,149,985, issued April 17, 1979, describes that gelling-resistant glycol compositions containing borate and silicate additives can be prepared. However, in order to produce a gelling-resistant composition, it was necessary to strictly control the order of addition of additives and the pH of the solution. This is difficult to control during manufacturing. Wing, U.S. Pat. No. 4,287,077, issued September 1, 1981, describes gelation-resistant glycol compositions to which are added an effective amount of silicone having polyoxyalkylene functionality. There is. While these silicone compounds are certainly effective, the process for making glycol compositions containing these compounds requires the addition of alkali metal silicates, which are always added to glycol compositions, to increase the corrosion resistance of the composition. The limitation is that these silicone compounds must be added before the process. In the present invention, phosphorus-
It is more effective in that a silane compound can be added. In UK Patent No. 2018266A of 17 October 1979:
The use of alkali metal salts of polymers of silylalkylphosphonates as corrosion inhibitors for metals in alcoholic or glycolic compositions is described. No. 4,333,843 to Wing et al., issued June 6, 1982, (RO) ₃ Si-(CH ₂ ) _o -O-P
Chemical formula of (O)(CH ₃ )-OR, where R is 1 carbon number
A gelation-resistant glycol composition is described by using an effective amount of a hydrolysis product of a compound having ~4 alkyl groups, n being an integer from 1 to 4;
This hydrolysis product is believed to be identical to the polymer of the UK patent. However, since these polymers are expensive, there are severe restrictions on their use in commercial production. Morehouse et al., U.S. Pat. No. 3,121,692 (columns 18 and 19), issued February 18, 1964, describes a gelling-resistant glycol composition formulation containing sodium silicate and aminosilanes. . However, it has been found that the compounds used in the present invention have far superior performance as anti-gel additives than the aminosilanes of the above-mentioned patents. The following patents relate to storage-stable related compositions containing siloxanes, but do not disclose the use of alkali metal silicates, glycols, and anti-gelling agents. U.S. Patent No. 3,234,144 (issued March 26, 1962)
Column 12 U.S. Patent No. 3248329 (issued April 26, 1966)
Column 19 U.S. Patent No. 3312622 (issued April 4, 1967)
Columns 21 and 22 U.S. Patent No. 3,337,496 (issued April 22, 1967)
Column 9: U.S. Patent No. 3,341,469 (issued September 12, 1967)
Column 9 The present invention relates to a glycol composition having gelation resistance comprising the following composition. (A) Alkylene glycol, alkylene glycol ether, or a mixture of both 85 to 98wt
%; (B) Effective amount for reducing corrosion of alkali metal silicates; (C) Effective amount of any of the following; () (RO) _3-n (R ¹ ) _n Si−R ² −O −P (O) (OR ³ ) (R ⁴ ) () [(RO) _3-n (R ¹ ) _n Si−R ² −O] ₂ P(O)
(R ⁴ ) and a mixture of () and where m is 0 to 2 R, R ³ and R ⁴ are alkyl groups having 1 to 4 carbon atoms R ¹ is an alkyl group having 1 to 4 carbon atoms, a phenyl group and an aralkyl group having 7 to 10 carbon atoms, and R ² is an alkylene group having 1 to 4 carbon atoms. The present invention also provides gelation resistance by adding to a glycol composition containing an alkali metal silicate or other corrosion inhibitor an effective amount to improve the gelation resistance of a compound represented by the formula: The present invention includes a method for producing a glycol composition having the following. () (RO) _3-n (R ¹ ) _n Si−R ² −O −P(O) (OR ³ ) (R ⁴ ) () [(RO) _3-n (R ¹ ) _n Si−R ² −O〕 ₂ P(O)
(R ₄ ) and a mixture of () and where m is 0 to 2 R, R ³ and R ⁴ are alkyl groups having 1 to 4 carbon atoms R ¹ is an alkyl group having 1 to 4 carbon atoms, a phenyl group and an aralkyl group having 7 to 10 carbon atoms, and R ² is an alkylene group having 1 to 4 carbon atoms. Examples of compounds falling within the above range where m is zero include methyl 3-(trimethoxysilyl)propyl methylphosphonate, butyl 2-
(Triethoxysilyl)ethylmethylphosphonate, propyl 3-(tripropoxysilyl)propylmethylphosphonate, and methyl 4-(trimethoxysilyl)butylmethylphosphonate. Examples of compounds falling within the above range where m is 1 include methyl 3-(methyldimethoxysilyl)propylmethylphosphonate, methyl 3-(methyldimethoxysilyl)propylmethylphosphonate,
-(methyldiethoxysilyl)propylmethylphosphonate, methyl 3-(dimethoxymethylsilyl)propylethylphosphonate, butyl 2-
(dimethoxymethylsilyl)ethylpropylphosphonate, propyl 3-(dipropoxymethylsilyl)propylmethylphosphonate and methyl 4-(dimethoxymethylsilyl)butylethylphosphonate. Examples of compounds falling within the above range where m is 2 include methyl 3-(dimethylmethoxysilyl)propylmethylphosphonate, methyl 3-(dimethylethoxysilyl)propylmethylphosphonate, and methyl 3-(methoxydimethylsilyl). ) Propyl butyl phosphonate, butyl 2
-(methoxydimethylsilyl(ethylethylphosphonate), propyl 3-(ethoxydiethylsilyl)propylmethylphosphonate, and ethyl 4-(methoxydimethylsilyl)butylethylphosphonate. Examples of compounds falling within the above range include bis -[3-(trimethoxysilyl)propyl]methylphosphonate, bis-[2-(trimethoxysilyl)ethyl]methylphosphonate, bis-[3-(tripropoxysilyl)propyl]methylphosphonate, bis-[4-( trimethoxysilyl)butyl]methylphosphonate, bis-[3-
(methyldimethoxysilyl)propyl]methylphosphonate, bis-[3-(methyl-diethoxysilyl)propyl]methylphosphonate, bis-
[3-(dimethylmethoxysilyl)propyl]methylphosphonate, and bis-[3-dimethylethoxysilyl)propyl]methylphosphonate. Examples of mixtures falling within the above range include one of trialkoxysilane, dialkoxyalkylsilane, or alkoxydialkylsilane having an omega haloalkylene group;
There is a crude product of the reaction with the dialkylalkylphosphonate. These compounds were published on June 6, 1978.
It can be prepared by the catalytic process shown in Plueddemann, US Pat. No. 4,093,641, or it can be readily prepared by the processes shown in column 1 of the above patent.
Other non-contact processes are shown below. These subgel resistant additives may be combined with other well-known corrosion inhibitors normally present in glycol compositions of this type, such as alkali metal borates, mercaptobenzotriazole compounds, nitrates, nitrites,
It is also effective in the presence of phosphates, benzoates, etc. Accordingly, the present invention relates to a single phase composition of the following composition: (A) 85-98 wt alkylene glycol, alkylene glycol ether or a mixture of both;
(B) an effective amount of an alkyl metal silicate; (C) an effective amount of any one of the following substances; () (RO) _3-n (R ¹ ) _n Si-R ² -O -P(O ) (OR ³ ) (R ⁴ ), () [(RO) _3-n (R ¹ ) _n Si−R ² −O] ₂ P(O)
(R ⁴ ), or a mixture with (), where m is 0 to 2, R, R ³ and R ⁴ are alkyl groups having 1 to 4 carbon atoms, and R ¹ is an alkyl group having 1 to 4 carbon atoms. , a phenyl group, an aralkyl group having 7 to 10 carbon atoms, and R ² are an alkylene group having 1 to 4 carbon atoms. Particularly preferred additive compounds have the following formula: () (RO) ₃ Si—(CH ₂ )— _o O −P(O)(CH ₃ )—OR, () [(RO) ₃ Si— (CH ₂ )) - _o O-] ₂ -P(O)CH ₃ , or a mixture of () and Here, R is an alkyl group having 1 to 4 carbon atoms, n
is an integer from 1 to 4. Glycols and glycol ethers that can be used in this composition include (1) glycols such as ethylene glycol, diethylene glycol, propylene glycol, and dipropylene glycol; (2) glycol monoethers such as methyl, ethyl, propyl, and butyl ethers of ethylene glycol; ,(3)
Glycol diethers such as the methyl and ethyl diethers of ethylene glycol, diethylene glycol, and dipropylene glycol.
Ethylene glycol, propylene glycol and the monomethyl ester of propylene glycol, ie methoxypropanol, are particularly suitable. Examples of known corrosion inhibitors and additives used in combination with the above-mentioned silane in the present invention are as follows: alkali metal silicates such as sodium metasilicate, potassium metasilicate, lithium metasilicate, sodium tetraborate, Alkali metal borates such as potassium tetraborate, sodium metaborate, potassium metaborate, alkali metal salts of mercaptobenzothiazole, alkali metal salts of tolyltriazole, alkali metal nitrates such as sodium nitrate, potassium nitrate, sodium nitrite, potassium nitrite, etc. There are alkali metal nitrites, alkali metal phosphates such as sodium phosphate and potassium phosphate, alkali metal benzoates, and various dyes. In the process of making the compositions of the present invention, one or more of the above-mentioned glycols are added to the non-silicate corrosion inhibitors mentioned above and other inhibitors such as mercaptobenzothiazole, tolyltriazole, nitrates, phosphates, etc. necessary for corrosion protection. Mix with sufficient quantity.
Next, set the desired pH of the solution, i.e. a value of 5 to 12,
It is preferably adjusted to 8 to 11 by adding an aqueous solution of an inorganic salt such as an alkali metal hydroxide, carbonate or phosphate. Furthermore, the above-mentioned alkali metal silicate is added to form a glycol composition having corrosion and gel resistance. The silane or mixture thereof can be added in an effective amount at any point during the manufacturing process. The effective amount of the silane that can result in a glycol composition having gelation resistance to achieve the objects of the present invention is about 0.001 to 5.0 wt%, preferably
0.002 to 0.5wt%, most preferably 0.005 to 0.5wt%
It is in the range of 0.2wt%. Effective amounts for corrosion protection of the above-mentioned corrosion inhibitors are well known in the prior art and will of course vary depending on the particular additive. Generally, the amount of silicates and borates used is 0.025 to 1.0 wt% for silicates and 0.1 to 1.0 wt% for borates based on the weight of the total solution.
2.0wt%, preferably 0.05 to 0.05% for silicate
0.5 wt%, ranging from 0.5 to 1.6 wt% for borate. In the present invention, when the amount of borate added is large within the desired amount range (1.0 to 2.0 wt%), the amount of silicate added is within the desired amount range (0.025 to 2.0 wt%).
0.3wt%).
In each case, it is not possible to determine the exact amount of silicate, due to its complex effects with other corrosion inhibitors, such as the aforementioned triazoles, nitrates, nitrites and phosphates. . Accelerated durability (aging) tests were conducted on Examples and Comparative Examples to compare and illustrate the gelation resistance of the compositions. In the test, a glycol composition was placed in a constant temperature bath maintained at 80, 90, and 95°C, and the number of hours or days until gel formation was observed was measured. The invention is illustrated in the following Preparation Methods, Examples and Comparative Examples. Preparation method 1 Put 800.0 g (4 mol) of 3-chloropropyltrimethoxysilane and 1000.0 g (8 mol) of dimethylmethylphosphonate in a 3-liter round-bottomed flask, attach a reflux condenser, and stir with a magnetic stirrer. The mixture was heated to 187°C over 45 minutes.
When a bubbler using mineral oil was attached to the outlet of the reflux condenser, gas generation was observed. The flask contents were held at 187°C for an additional 22.5 hours.
In this case, no gas evolution was observed, and the reaction product was then stopped from heating and cooled to room temperature. After cooling, 1436.9 g of a light tan liquid was obtained. Gas chromatographic analysis of the crude reaction product revealed the following composition: 44.4% dimethylmethylphosphonate; 39.6% methyl 3-(trimethoxysilyl)propylmethylphosphonate;
Two small unidentified peaks were observed at 7.2% bis-[3-trimethoxysilyl)propyl]methylphosphonate. One comes before dimethylmethylphosphonate and the other after bis-[3-(trimethoxysilyl)propyl]methylphosphonate. A portion of this reaction product was distilled under reduced pressure at approximately 2 mmHg to remove unreacted dimethylmethylphosphonate.
Collected as a fraction between 30 and 50℃, and a fraction between 112 and 114℃. Methyl 3-(trimethoxysilyl)propyl methylphosphonate has the structural formula:
Identified by gas chromatography, NMR and mass spectrometry. Gas chromatographic analysis of the fraction at about 160-200℃ shows that this is Bis-[3-(trimethoxysilyl)propyl]
Comparison with a standard sample prepared according to the method described in US Pat. No. 4,093,641 revealed that methylphosphonate must be predominant. Examples 1 to 8 52.0 g of a 25 wt% ethylene glycol solution of sodium metaborate pentahydrate was added to 917.0 g of ethylene glycol. A 331/3% aqueous solution of sodium nitrate (6.0 g) was added and stirred until completely dissolved. Then 50% of sodium tolyltriazole
% aqueous solution was added. Next, the pH of the solution is 8.4~
It was adjusted to 8.5 using a 10% potassium aqueous solution.
Aqueous solution of sodium metasilicate pentahydrate (water 10.0g
(3.0 g dissolved in ) was added to the above mixture. Although this solution and the addition of various stabilizers
Table 1 shows the gel formation prevention properties (stability) at 80°C and 90°C. However, the number of days of stability shown in Table 1 is the number of days until the formation of gel is first observed in the eye.

[Table] Based on the consideration of the data shown in Table 1,
Methyl 3-(trimethoxysilyl)propylmethylphosphonate and bis-[3-(trimethoxysilyl)propyl]methylphosphonate are
It is clear that even at low concentrations of 30 ppm and 20 ppm, these additives are far more effective in increasing gel stability than the comparative examples. An unpurified synthetic reaction mixture is also effective as an antigelation agent, although it is not as effective as the pure silane mentioned above. Examples 9-13 Even if phosphorus-modified silanes are added after silicate or other corrosion inhibitors are added to the glycol composition,
This example shows that it is effective in preventing gel formation. Stability of commercially available antifreeze containing 5 types of silicates
Evaluation was performed at 95°C. Next, add 0.02% of the unpurified synthetic reaction product (mixture) shown in Preparation Method 1 to each sample.
The stability was evaluated under the same conditions. The results are shown in Table 2.

[Table] * Comparative example without preparation method 1
Purify the synthesis reaction mixture
Added 0.02wt%
Examples 14 to 18 Certain commercially available antifreeze products exhibited a stability value of 6 hours in a constant temperature bath at 95°C. Addition of a small amount of methyl 3-(trimethylsilyl)propyl methylphosphonate to this unstable coolant significantly increased the time to gel formation under the same conditions. The results are shown in Table 3.

[Table] Examples 19 and 20 Using the same method as shown in Examples 14 to 18, only the stabilizer added to a specific commercially available antifreeze was bis-
The experiment was carried out by changing to [3-(trimethoxysilyl)propyl]methylphosphonate. In Example 19, the addition of 200 ppm of bis-[3-(trimethoxysilyl)propyl]methylphosphonate improved the gel formation time from 6 hours to 6 days. In Example 20, by adding 1000 ppm of the same compound, the gel formation time was 14 days. Examples 21 and 22 25% ethylene glycol solution of sodium metaborate pentahydrate in 917.0 g ethylene glycol
Added 52.0g. A 331/3% aqueous solution (6.0 g) of sodium nitrate was added and stirred until sufficiently dissolved. Then a 50% aqueous solution of sodium tolyltriazole
2.0g was added. Therefore, the pH of the solution was adjusted to 5.8-5.9 using a 25% caustic aqueous solution. Sodium metasilicate pentahydrate was dissolved in 20.0 g of water, and added with stirring to form a composition with a high silicate concentration and a composition with a low silicate concentration. of these two solutions
Table 4 shows the stability at 80 DEG C. and 90 DEG C. and the stability test results when 0.1%, ie, 1000 ppm of methyl 3-(trimethoxysilyl)propyl methylphosphonate was added as a stabilizer to both.

[Table] From the above results, the gel formation time is short when the sodium silicate concentration is high (7000 ppm), but the gel formation time becomes longer when the silane of the present invention is used. At low silicate concentrations (5000 ppm), the silanes of the present invention have very long gel formation times. Examples 23 and 24 Sufficient amounts of various stabilizers were added to 50 ppm each of commercially available silicate-containing antifreeze solutions. The time required for visible silica gel to form in these solutions was measured at 90-95°C. Table 5 shows the average gel formation time measured three times in each case.

[Table] Nate

Claims (1)

[Scope of Claims] 1. Glycol composition having gelation resistance consisting of the following composition: (A) 85 to 98 wt of alkylene glycol, alkylene glycol ether, or a mixture of both.
%; (B) Effective amount for reducing corrosion of alkali metal silicates; (C) Effective amount of any of the following substances; () (RO) _3-n (R ¹ ) _n Si−R ² −O −P(O)(OR ³ )(R ⁴ ) () [(RO) _3-n (R ¹ ) _n Si−R ² −O] ₂ P(O)
(R ⁴ ), or a mixture of () and; where m is 0 to 2 R, R ³ , R ⁴ are alkyl groups having 1 to 4 carbon atoms, R ¹ is an alkyl group having 1 to 4 carbon atoms, A phenyl group and an aralkyl group having 7 to 10 carbon atoms, and R ² is an alkylene group having 1 to 4 carbon atoms. 2. The composition of claim 1, wherein the alkylene glycol is ethylene glycol. 3. The composition of claim 1, wherein the alkylene glycol is propylene glycol. 4. The composition of claim 1, wherein the alkylene glycol ether is monomethyl ether of propylene glycol. 5. The composition of claim 1, wherein (A) is an alkylene glycol and also contains an effective amount of an alkali metal borate to reduce corrosion. 6. The composition of claim 5, wherein R is a methyl group and m is zero. 7. Glycol compositions having gelling resistance characterized by adding to glycol compositions containing alkali metal silicates and other corrosion inhibitors an effective amount that improves the gelling resistance of a substance of the formula: Manufacturing method: () (RO) _3-n (R ¹ ) _n Si−R ² −O −P(O) (OR ³ ) (R ⁴ ) () [(RO) _3-n (R ¹ ) _n Si −R ² −O] ₂ P(O)
(R ⁴ ), or a mixture of () and , where m is 0 to 2 R, R ³ , and R ⁴ are alkyl groups having 1 to 4 carbon atoms, and R ¹ is an alkyl group having 1 to 4 carbon atoms. , a phenyl group and an aralkyl group having 7 to 10 carbon atoms, and R ² is an alkylene group having 1 to 4 carbon atoms.