US3553137A - Corrosion inhibitor for methoxypropanol - Google Patents

Corrosion inhibitor for methoxypropanol Download PDF

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Publication number
US3553137A
US3553137A US671588A US3553137DA US3553137A US 3553137 A US3553137 A US 3553137A US 671588 A US671588 A US 671588A US 3553137D A US3553137D A US 3553137DA US 3553137 A US3553137 A US 3553137A
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Prior art keywords
methoxypropanol
corrosion inhibitor
piperazine
composition
alkali metal
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US671588A
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Conrad D Woods
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Dow Chemical Co
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Dow Chemical Co
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    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09K—MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
    • C09K5/00—Heat-transfer, heat-exchange or heat-storage materials, e.g. refrigerants; Materials for the production of heat or cold by chemical reactions other than by combustion
    • C09K5/20—Antifreeze additives therefor, e.g. for radiator liquids

Definitions

  • Antifreeze fluid is usually essentially ethylene glycol, though lower alkanols are used to some extent.
  • a combination of several corrosion inhibitors is added because a typical engine contains a variety of metals in contact with the fluid and no one inhibitor will protect all these metals.
  • a great variety of inhibitors has been suggested in the art; these include the metal borates, phosphates, arsenates, arsenites, molybdates, chromates, nitrates, nitrites, amines, piperazines, benzothiazole, and benzotriazole, and some of their combinations.
  • Methoxypropanol has also proven to be suitable as a heat transfer agent but, in itself, it is corrosive to the commonly used cooling system metals.
  • the corrosiveness of methoxypropanol on the common metals of construction is inhibited by dissolving in the methoxypropanol a small but effective amount of a corrosion-inhibiting composition comprising an alkali metal nitrite, a piperazine, and benzotriazole.
  • the alkali metal nitrite can be sodium nitrite, potassium nitrite, or the other alkali metal nitrites.
  • the piperazine compound can be piperazine itself, an alkylpiperazine wherein the alkyl group contains up to eight carbon atoms, or an amino-alkylpiperazine wherein the alkyl group contains up to eight carbon atoms.
  • alkyl or amino-alkylpiperazines which are useful are Z-methylpiperazine, N-butylpiperazine, N-(2- aminoethyl)piperazine, and N-(3-aminopropyl)piperazine.
  • an inhibited composition such as one suitable for use as a heat-transfer medium
  • the above inhibitor system is dissolved in the methoxypropanol in an effective concentration, suitably about 0.5 to 3.0% by weight. This is an especially small weight percent of inhibitor and thus presents an economical concentrate.
  • an effective concentration suitably about 0.5 to 3.0% by weight.
  • the above composition may be diluted with water, suitably to a concentration of from 30 to by volume, for use as an automotive antifreeze.
  • the undiluted material is also useful as a heattransfer medium.
  • An inhibited methoxypropanol composition was prepared by blending the following ingredients. The concentration is given in weight percent based on the total mixture.
  • composition was tested for corrosiveness according to the standard glassware test procedures for automotive antifreezes described in the following methods: ASTM D1384, General Motors Corp. GM 1899M, and Ford Motor Co. BLl-l, each sample being diluted to 33 /3 by volume, as specified in the methods.
  • composition was tested according to the General Motors Corp. simulated service test (G.M. 1899M) procedure.
  • the corrosion loss in mg./ sq. in. is reported 'below in Table II.
  • a corrosion inhibitor comprising:
  • Component Percentage by weight (a) Benzotriazole 1-20 (b) Alkali metal nitrite 1-20 (c) Piperazine, alklypiperazine or aminoalkylpiperazine wherein the alkyl or aminoalkyl moiety contains 1-8 carbon atoms Balance all percentages being based upon the total weight of (a), (b) and (c).
  • a corrosion inhibitor as defined in claim 1 comprising:
  • Component Percent by weight (a) 8-12 (b) 8-12 Balance 3.
  • a corrosion inhibitor as defined in claim 1 wherein the piperazine compound is an amino-alkylpiperazine compound having up to eight carbon atoms in the alkyl group.
  • An anticorros-ive composition consisting essentially of methoxypropanol containing a small but effective proportion of a corrosion inhibitor as defined in claim 1.
  • composition as defined in claim 7 wherein the corrosion inhibitor comprises from 0.5 to 3.0% by weight of the composition, based on the methoxypropanol.
  • composition as defined in claim 8 wherein the corrosion inhibitor comprises:
  • Component Percent by weight (a) 8-12 (b) 8-12 (c) Balance 10.
  • An antifreeze composition consisting essentially of the composition as defined in claim 2 and water wherein the water comprises from 30 to by volume of the fluid.

Abstract

THE CORROSIVE EFFECT OF METHOXYPROPANOL IS INHIBITED BY A THREE COMPONENT MIXTURE OF (1) AN ALKALI METAL NITRITE, (2) A PIPERAZINE, AND (3) BENZOTRIAZOLE.

Description

United States Patent O 3,553,137 CORROSION INHIBITORS FOR METHOXYPROPANOL Conrad D. Woods, Midland, Mich., assignor to The Dow Chemical Company, Midland, Mich., a corporation of Delaware No Drawing. Filed Sept. 29, 1967, Ser. No. 671,588 Int. Cl. C09k 3/02; C2315 11/14, 11/18 US. Cl. 252-75 10 Claims ABSTRACT OF THE DISCLOSURE The corrosive effect of methoxypropanol is inhibited by a three component mixture of (1) an alkali metal nitrite, (2) a piperazine, and (3) benzotriazole.
BACKGROUND OF THE INVENTION Antifreeze fluid is usually essentially ethylene glycol, though lower alkanols are used to some extent. A combination of several corrosion inhibitors is added because a typical engine contains a variety of metals in contact with the fluid and no one inhibitor will protect all these metals. A great variety of inhibitors has been suggested in the art; these include the metal borates, phosphates, arsenates, arsenites, molybdates, chromates, nitrates, nitrites, amines, piperazines, benzothiazole, and benzotriazole, and some of their combinations. Methoxypropanol has also proven to be suitable as a heat transfer agent but, in itself, it is corrosive to the commonly used cooling system metals.
SUMMARY OF THE INVENTION It has now been discovered that a three component system comprising an alkali metal nitrite, a piperazine and benzotriazole is a very effective corrosion inhibitor for methoxypropanol. By the latter term I means to include both Z-methoxy-l-propanol and 1-methoxy-2-propanol. The commercially available material is predominantly the latter but contains a small proportion of the former.
According to this invention, the corrosiveness of methoxypropanol on the common metals of construction, particularly those used in heat-exchangers, is inhibited by dissolving in the methoxypropanol a small but effective amount of a corrosion-inhibiting composition comprising an alkali metal nitrite, a piperazine, and benzotriazole.
The alkali metal nitrite can be sodium nitrite, potassium nitrite, or the other alkali metal nitrites.
The piperazine compound can be piperazine itself, an alkylpiperazine wherein the alkyl group contains up to eight carbon atoms, or an amino-alkylpiperazine wherein the alkyl group contains up to eight carbon atoms. Examples of alkyl or amino-alkylpiperazines which are useful are Z-methylpiperazine, N-butylpiperazine, N-(2- aminoethyl)piperazine, and N-(3-aminopropyl)piperazine.
"ice
TABLE I.-CORROSION INHIBITOR COM- POSITION Percent by weight Useful Preferred Components Plperazine compound Benzotriazole Alkali metal nitrite In formulating an inhibited composition, such as one suitable for use as a heat-transfer medium, the above inhibitor system is dissolved in the methoxypropanol in an effective concentration, suitably about 0.5 to 3.0% by weight. This is an especially small weight percent of inhibitor and thus presents an economical concentrate. As optional additives there may also be included dyes, acidbase indicators, water-pump lubricants, antifoam agents, or other conventional inhibitors or additives but this invention does not concern them. The above composition may be diluted with water, suitably to a concentration of from 30 to by volume, for use as an automotive antifreeze. The undiluted material is also useful as a heattransfer medium.
DESCRIPTION OF PREFERRED EMBODIMENTS The practice of our invention is illustrated by the following example.
An inhibited methoxypropanol composition was prepared by blending the following ingredients. The concentration is given in weight percent based on the total mixture.
Component: Weight percent Methoxypropanol 98.3 Piperazine 1.0 Benzotriazole 0.1 Sodium nitrite 0.1 Water 1 0.5
Water was added so as to facilitate the solubility of the nitrite; its presence is not necessary in the antifreeze concentrate. I
The above composition was tested for corrosiveness according to the standard glassware test procedures for automotive antifreezes described in the following methods: ASTM D1384, General Motors Corp. GM 1899M, and Ford Motor Co. BLl-l, each sample being diluted to 33 /3 by volume, as specified in the methods.
Also, the composition was tested according to the General Motors Corp. simulated service test (G.M. 1899M) procedure. The corrosion loss in mg./ sq. in. is reported 'below in Table II.
TABLE II.CORROSION TESTS Corrosion loss mgs./sq. in.
Observed G.M. simulated G.M. glassware service Allowable Observed Ford glassware Allowable ASTM
Observed Observed Coppen S d A1uminum-- 3 I clairn.: v. 1. A corrosion inhibitor comprising:
Component: Percentage by weight (a) Benzotriazole 1-20 (b) Alkali metal nitrite 1-20 (c) Piperazine, alklypiperazine or aminoalkylpiperazine wherein the alkyl or aminoalkyl moiety contains 1-8 carbon atoms Balance all percentages being based upon the total weight of (a), (b) and (c).
2. A corrosion inhibitor as defined in claim 1 comprising:
Component: Percent by weight (a) 8-12 (b) 8-12 Balance 3. A corrosion inhibitor as defined in claim 1 wherein the piperazine compound is an alkylpiperazine having up to eight carbon atoms in the alkyl group.
4. A corrosion inhibitor as defined in claim 1 wherein the piperazine compound is an amino-alkylpiperazine compound having up to eight carbon atoms in the alkyl group.
5. A corrosion inhibitor as defined in claim 1 wherein the piperazine compound is piperazine.
6. A corrosion inhibitor as defined in claim 1 wherein the alkali metal nitrite is sodium nitrite.
7. An anticorros-ive composition consisting essentially of methoxypropanol containing a small but effective proportion of a corrosion inhibitor as defined in claim 1.
8. A composition as defined in claim 7 wherein the corrosion inhibitor comprises from 0.5 to 3.0% by weight of the composition, based on the methoxypropanol. I
9. A composition as defined in claim 8 wherein the corrosion inhibitor comprises:
Component: Percent by weight (a) 8-12 (b) 8-12 (c) Balance 10. An antifreeze composition consisting essentially of the composition as defined in claim 2 and water wherein the water comprises from 30 to by volume of the fluid.
References Cited UNITED STATES PATENTS 1,780,927 11/1930 Jordan 25273 2,164,564- 7/1939 Britton, et a1. 25277 3,291,741 12/1966 Monroe, et a1. 252-76 3,414,519 12/1968 Beynon 252-75 US. Cl. X.R.
US671588A 1967-09-29 1967-09-29 Corrosion inhibitor for methoxypropanol Expired - Lifetime US3553137A (en)

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US67158867A 1967-09-29 1967-09-29

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BE (1) BE721578A (en)
DE (1) DE1771985A1 (en)
FR (1) FR1588954A (en)
GB (1) GB1243081A (en)
NL (1) NL6811906A (en)

Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4098720A (en) * 1973-10-25 1978-07-04 Chemed Corporation Corrosion inhibition
US4160740A (en) * 1977-10-17 1979-07-10 The Dow Chemical Company Inhibited aqueous, methoxypropanol coolant adjusted to a pH between about 6 and 9
US4382870A (en) * 1981-07-06 1983-05-10 Northern Petrochemical Company Antifreeze corrosion inhibitor composition for aluminum engines
US4426309A (en) 1981-07-06 1984-01-17 Northern Petrochemical Company Antifreeze corrosion inhibitor composition for aluminum engines
US4719035A (en) * 1984-01-27 1988-01-12 The United States Of America As Represented By The Secretary Of The Air Force Corrosion inhibitor formulation for molybdenum tungsten and other metals
US6119713A (en) * 1998-11-04 2000-09-19 Pino; Wilton J. Apparatus to prevent rapid multiple flushing
US6265667B1 (en) 1998-01-14 2001-07-24 Belden Wire & Cable Company Coaxial cable
US6469078B1 (en) * 1999-05-21 2002-10-22 Ciba Specialty Chemicals Corporation Molecular weight increase and modification of polycondensates
US20110309274A1 (en) * 2002-06-24 2011-12-22 Parsons Natan E Electrically operated valve for delivering water

Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4098720A (en) * 1973-10-25 1978-07-04 Chemed Corporation Corrosion inhibition
US4160740A (en) * 1977-10-17 1979-07-10 The Dow Chemical Company Inhibited aqueous, methoxypropanol coolant adjusted to a pH between about 6 and 9
US4382870A (en) * 1981-07-06 1983-05-10 Northern Petrochemical Company Antifreeze corrosion inhibitor composition for aluminum engines
US4426309A (en) 1981-07-06 1984-01-17 Northern Petrochemical Company Antifreeze corrosion inhibitor composition for aluminum engines
US4719035A (en) * 1984-01-27 1988-01-12 The United States Of America As Represented By The Secretary Of The Air Force Corrosion inhibitor formulation for molybdenum tungsten and other metals
US6265667B1 (en) 1998-01-14 2001-07-24 Belden Wire & Cable Company Coaxial cable
US6119713A (en) * 1998-11-04 2000-09-19 Pino; Wilton J. Apparatus to prevent rapid multiple flushing
US6469078B1 (en) * 1999-05-21 2002-10-22 Ciba Specialty Chemicals Corporation Molecular weight increase and modification of polycondensates
US20110309274A1 (en) * 2002-06-24 2011-12-22 Parsons Natan E Electrically operated valve for delivering water

Also Published As

Publication number Publication date
GB1243081A (en) 1971-08-18
DE1771985A1 (en) 1972-02-10
FR1588954A (en) 1970-03-16
BE721578A (en) 1969-03-27
NL6811906A (en) 1969-04-01

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