US3607757A

US3607757A - Corrosion resistant antifreeze compositions

Info

Publication number: US3607757A
Application number: US747093A
Authority: US
Inventors: Harold Mcdonald
Original assignee: Stauffer Chemical Co
Current assignee: Stauffer Chemical Co
Priority date: 1968-07-24
Filing date: 1968-07-24
Publication date: 1971-09-21
Anticipated expiration: 1988-09-21

Abstract

Corrosion resistant antifreeze compositions consisting essentially of at least one antifreeze fluid having from 1 to 4 carbons inclusive and from 1 to 3 hydroxy groups inclusive and a minor but effective amount sufficient to inhibit corrosion of an alkali metal dialkyl phosphate. The alkali metal dialkyl phosphate can be represented by the formula:

D R A W I N G

Description

United States Patent [72] Inventor Harold McDonald Harrington Park, NJ. [21 Appl. No. 747,093 [22] Filed July 24, 1968 [45] Patented Sept. 21, 1971 [73] Assignee Stauffer Chemical Company New York, N.Y.

[54] CORROSION RESISTANT ANTIFREEZE FOREIGN PATENTS 802,347 10/1956 GreatBritain Primary Examiner- Leon D. Rosdol Assistant Examiner-D. Silverstein Atlorneys Donald M. MacKay, Robert C. Sullivan, Daniel C.

Block and Paul J. Juettner ABSTRACT: Corrosion resistant antifreeze compositions consisting essentially of at least one antifreeze fluid having from 1 to 4 carbons inclusive and from 1 to 3 hydroxy groups inclusive and a minor but effective amount sufficient to inhibit corrosion of an alkali metal dialkyl phosphate. The alkali metal dialkyl phosphate can be represented by the formula:

wherein R is an alkyl group containing from about 8 to about 16 carbon atoms inclusive, and M is an alkali metal ion.

CORROSION RESISTANT ANTIFREEZE COMPOSITIONS This invention relates to antifreeze compositions and more particularly to corrosion resistant antifreeze compositions useful in automobile cooling systems.

It is well known that the corrosive action of water is particularly troublesome in automobile cooling systems. This is due to the temperatures prevailing and to the presence of oxygen and carbon dioxide which are introduced by air leaks in the circulatory system or by the normal aeration process that goes on at the top of the radiator tank. One particular corrosive area is the uppermost portion of the radiator. There the solder joints are preferentially attacked causing water leakage.

It has now been discovered that corrosion can be substantially reduced at the solder joints by incorporating in the commonly employed antifreeze fluids, a minor but effective amount sufficient to inhibit corrosion of an alkali metal dialkyl phosphate of the formula:

ll RO-JEf-OR wherein R is an alkyl group containing from about eight to about 16 carbon atoms inclusive, and M is an alkali metal ion. lllustrative of the alkali metal ions are sodium, lithium and potassium. While ammonium is not truly a member of the alkali metal series, it is a clear equivalent for the alkali metal ions and is generally considered to be within the term or an equivalent of alkali metals. It is so considered in the present case. Sodium ions and ammonium ions are preferred in the present invention because of their low cost and efficiency. 11- lustrative of the alkyl groups as represented by the substituent R are octyl, nonyl, decyl, undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl, hexadecyl and the like. Of these substituents represented by R, decyl has been found to be preferred as such compounds provide exceptional corrosion inhibiting properties. Particularly preferred for similar reasons are the branched decyl groups wherein the decyl group is derived from a highly branched primary alcohol.

Illustrative and typical of the antifreeze fluids which can be employed are the volatile monohydroxy compounds as well as the nonvolatile polyhydroxy compounds or mixtures. Preferably the antifreeze fluids will consist essentially of at least one compound having from one to four carbon atoms inclusive, and from one to three hydroxy groups inclusive. Exemplary of the volatile compounds are methanol, ethanol, and isopropanol. Exemplary of the nonvolatile compounds are ethylene glycol, propylene glycol, diethylene glycol, and glycerol.

1n the conduct of this invention, the alkali metal dialkyl phosphate is used in an amount of from about 0.01% to about 5% and preferably from about 0. 1% to about 2.0%

If desired, the alkali metal dialkyl phosphates can be used in combination with other inhibitors to include both organic and inorganic compounds. Among the former are mineral and vegetable oils, their sulfonated products and amines, amides and mercaptans. The inorganic compounds include borates, nitrates, nitrites, phosphates, molybdates, arsenites and carbonates. Exemplary of typical inhibitors employed include borax, sodium nitrites, sodium mercaptobenzothiazole, sodium citrate, triethanoloamine phosphate, hydroquinone. sodium chromate, sodium silicate, sodium sulfite, and sodium benzoate.

The following examples will serve to illustrate the invention and its preferred embodiments. All parts and percentages in said examples are by weight unless otherwise specified.

EXAMPLE 1 Pursuant to ASTM D 1384-65, a standard antifreeze test solution was prepared consisting of the following ingredients:

Ethylene glycol 77.5% Propylene glycol 10.0% Dicthylene glycol 5.0% Borax [0H,0) 2.5% Water 5.0

An identical solution was also prepared but for the addition of 0.10% of sodium didecyl phosphate. Air was introduced into the solutions at approximately ml./min., the test solutions were maintained at F. and agitated. Pursuant to the aforesaid test, specimens of steel, brass, aluminum, copper and solder were suspended in the test solutions for 2 weeks. The air was then shut off, the temperature was reduced to am bient temperature, the agitation was discontinued, and the samples were suspended for an additional week in the test solutions under static conditions. At the end of this period, the test samples were removed, cleaned according to the aforesaid method, and the weight loss calculated. The solder samples immersed in the control solution containing no sodium didecyl phosphate exhibited a weight loss of 46.30%. The solder samples immersed in the sodium didecyl phosphate containing solution exhibited a weight loss of 17.1 1%.

EXAMPLE 2 In accordance with the procedure of Example 1 identical solutions are prepared but for the substitution of sodium dioctyl phosphate for sodium didecyl phosphate. The results found are in general agreement with the previous example.

Although the corrosion resistant antifreeze compositions of this invention will commonly be employed with tap water, these compositions can also be employed in the permanenttype package system which normally contain deionized water.

EXAMPLE 3 Since the alkali metal phosphates form stable emulsion in water they can be used to advantage as corrosion inhibitors in aqueous cooling systems or in general metal chemical apparatus. These phosphates are particularly preferred for inhibiting corrosion of ferrous metals, and solder, and can be used in an amount from about 0.01% to about 5% and preferably from about 0.1% to about 1%.

EXAMPLE 4 An 0.1% aqueous solution of sodium didecyl phosphate was prepared and placed in a 3 litter rectangular container. Sample 1 inch X 2 inch solder and milder steel coupons were placed on a plastic disc. The disc was rotated through the test solutions to permit alternate aqueous and air exposure. The samples were rotated for 60 days, then cleaned according to standard techniques (i.e. the solder samples were immersed in a boiling solution of 1% glacial acetic acid according to ASTM D 1384 and the steel coupons were cleaned by immersion in a boiling solution of 5% ammonium citrate and cleaned with a brush to remove deposits). The cleaned coupons were weighed and the weight loss computed. The test was repeated substituting an 0.1% aqueous solution of sodium chromate for the phosphate solution and the results are compared in the following table with a control solution containing only water.

The water control was rotated for only 24 days.

Sodium dioctyl phosphate is substituted for sodium didecyl phosphate in the above test and the results are in general agreement.

What is claimed is:

l. A corrosion resistant alcoholic antifreeze composition consisting essentially of at least one antifreeze fluid having from one to four carbons inclusive and from one to three hydroxy groups inclusive and a minor but effective amount sufficient to inhibit corrosion of an alkali metal dialkyl phosphate of the formula:

wherein R is an alkyl group containing from about eight to about 16 carbon atoms inclusive, and M is an alkali metal ion.

2. The composition of claim 1 wherein the alkali metal dialkyl phosphate is present in an amount of from about 0.01% to about 5.0%

' 3. The composition of claim 1 wherein the alkali metal dialkyl phosphate is present in an amount of from about 0.1% to about 2.0%.

4. The composition of claim 3 wherein the alkali metal dialkyl phosphate is sodium didecyl phosphate.

5. The composition of claim 3 wherein the alkali metal dialkyl phosphate is sodium dioctyl phosphate.

6. The composition of claim 1 wherein the antifreeze fluid is wherein R is an alkyl group containing from about eight to about 16 carbon atoms inclusive, and M is an alkali metal ion.

10. The composition of claim 9 wherein the alkali metal dialkyl phosphate is present in an amount of from about 0.l0% to about 5%.

11. The composition of claim 9 wherein the alkali metal dialkyl phosphate is present in an amount of from about 0.1% to about 1%.

12. A composition of claim 1 wherein the alkali metal dialkyl phosphate is sodium didecyl phosphate.

It is certified that. error appmzars :in the abmvc-jdanilfir-r7 pntuni: and that said Lctttors Patent are hernby corrected as; shown below:

Claim 10, line 2, "0.10%" should be --O. Ol%-.

Signed and sealed this 21st day ofMarch 1972.

(SEAL) Attest:

EDWARD M.FLETCHER, JR. ROBERT GOTTSCHALK Commissioner of Patents Attesting Officer

Claims

2. The composition of claim 1 wherein the alkali metal dialkyl phosphate is present in an amount of from about 0.01% to about 5.0%
3. The composition of claim 1 wherein the alkali metal dialkyl phosphate is present in an amount of from about 0.1% to about 2.0%.
4. The composition of claim 3 wherein the alkali metal dialkyl phosphate is sodium didecyl phosphate.
5. The composition of claim 3 wherein the alkali metal dialkyl phosphate is sodium dioctyl phosphate.
6. The composition of claim 1 wherein the antifreeze fluid is a mixture of ethylene glycol, propylene glycol, and diethylene glycol.
7. A composition of claim 6 additionally containing a borax corrosion inhibitor.
8. A composition of claim 1 wherein the antifreeze fluid is a mixture of ethylene glycol, propylene glycol, and diethylene glycol and the phosphate inhibitor is sodium didecyl phosphate.
9. A corrosion resistant composition consisting essentially of water and a minor but effective amount sufficient to inhibit corrosion of an alkali metal dialkyl phosphate of the formula:
10. The composition of claim 9 wherein the alkali metal dialkyl phosphate is present in an amount of from about 0.10% to about 5%.
11. The composition of claim 9 wherein the alkali metal dialkyl phosphate is present in an amount of from about 0.1% to about 1%.
12. A composition of claim 1 wherein the alkali metal dialkyl phosphate is sodium didecyl phosphate.