JPH0344076B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates generally to organosilicon compounds, and more particularly to selected carboxy-substituted organosilicon compounds useful in silicate-containing antifreezes. Corrosion-inhibiting thermally conductive compositions in aqueous alcoholic solutions have traditionally been widely used in heat exchange systems associated with internal combustion engines, solar systems, etc., to lower the freezing point of refrigerants, increase their boiling points, and prevent corrosion. have provided. Because common alcohol-based heat transfer liquids, such as automotive antifreeze, have a tendency to corrode heat transfer metal (e.g. aluminum, copper, iron, steel, and solder) surfaces, these liquids are generally Contains corrosion inhibitors to minimize corrosion. Two US patents are of particular interest because their primary aspects are believed to represent antifreeze technology. That is, US Pat. Nos. 3,341,469 and 3,337,496 use organosiloxane/silicate copolymers,
Disclosed are hydroalcoholic compositions in which the siloxane can contain a polyethyleneoxyorganosilicon species. As a further example, U.S. Pat.
No. 3,198,820 discloses a hydroalcoholic antifreeze containing a carboxylorganosiloxane/silicate copolymer. Corrosion-inhibiting thermally conductive compositions of the type described in the '469 and '496 patents are widely used. This type of composition typically has an excellent shelf life, does not attack rubber parts in cooling systems, is characterized by a low degree of foam formation, and has a wide temperature range even after long-term use. Useful for many years. In addition to providing corrosion protection for cooling system metals, the art has also recognized the need to provide non-gelling antifreeze in concentrated form. That is, U.S. Pat. No. 4,149,985 teaches that the timing of addition of silicates to such antifreeze concentrates to minimize stability problems of concentrated silicates during storage.
It teaches that the PH should be between 9.5 and 10.5 (giving a final concentrate PH of about 11). Unfortunately, these antifreeze concentrates, although they offer reasonable flexibility in manufacture and use, can exhibit gelation problems over time. Many previous patents in this field, such as the '469, '496, '985 and '820 patents mentioned above, relate to non-gelling and gel formation in ethylene glycol concentrates. This suggests that a large number of silicates are useful in producing stable polymers from inorganic silicates that are free from manufacturing and undesirable problems. These previous patents also suggest that the PH can be varied widely, disclosing that the typical range is from about 7.0 to 12.0. Previous work in this area also suggests that relatively large amounts of silicates (as high as 5000 ppm Si) can be adequately stabilized. However, these prior art suggestions have not been found to be particularly useful in predicting the suitability of silanes for stabilizing silicates in aqueous antifreezes. For example, the invention disclosed in commonly assigned U.S. patent application Ser. It has been discovered that compared to cryogens, it protects aluminum from corrosion very effectively and makes silicates resistant to gelation in concentrates when selected silanes are used. Further previous work in this area includes UK patent no.
2018266A and U.S. Patent No. 4333843 and No.
This is reflected in No. 4386154. In general, this prior work has proposed the use of a wide variety of siliconate/phosphonate compounds as stabilizers against gel formation of silicates in antifreeze agents. The use of alkali metal and tetraalkylammonium derivatives is also disclosed. In addition to the above, the prior art is replete with attempts to provide antifreeze formulations that are resistant to gelation and provide the desired protection to the engine's cooling system. The essentially homogeneous focus, in the opinion of the applicant, has been on the ability of concentrates of antifreeze formulations to avoid undesired gelling. However, for antifreeze manufacturers, the technology is to dilute the antifreeze concentrate with water to obtain an antifreeze for use at 50% by volume (i.e., dilute the antifreeze concentrate with an equal volume of water). It is actually true. We now demonstrate that many silicone stabilizers that are satisfactory in providing stability in antifreeze concentrates destabilize the silicates in the water-diluted or as-used antifreeze and that silicate corrosion inhibitors It has been discovered that a portion of the molecule appears to become an insoluble species in solution. Although very unlikely, this would result in a substantial loss of corrosion inhibition efficiency. Thus, destabilization in providing antifreeze for use at this dilution is a significant obstacle that must be overcome. The stability of antifreeze concentrates in concentrate form ensures that the concentrate retains the desired corrosion protection intended for silicate antifreeze formulations upon preparation of using antifreeze by dilution with water. does not provide any guarantee that it will. In addition to the potential loss of corrosion protection, destabilization often precipitates silicates and causes blockages in the radiator tubes of automotive cooling systems. It has also been discovered that many silicates are at least aggressive towards aluminum surfaces, ie, such silanes tend to promote corrosion of aluminum. Therefore, to provide a useful antifreeze for systems with aluminum surfaces,
It would be highly desirable to use a silane that is at least relatively passive toward aluminum. Furthermore, it would be highly desirable to provide an antifreeze agent that can have greater flexibility in formulation while retaining adequate stability. For example, antifreeze agents with high RA (ie, reverse alkalinity) are often desirable. This allows the desired working pH to be maintained over a long period of time. However, such high RA compositions generally tend to reduce the desired stability. Similarly, although it is often desirable to incorporate supplementary corrosion inhibitors, many of which are ionic in nature, the presence of ionic supplementary corrosion inhibitors tends to exacerbate silicate stability problems. be. The synthesis of certain alkoxy derivatives is also described in the literature. That is, the Journal of American Oil Chemists Society (Jo
−urnal of American Oil Chemists’ Society),
In volume 51, pages 363-367, August 1974 issue,

[wherein R is selected from the group consisting of alkyl, aryl, alkoxyalkyl, alkoxyaryl and mixtures thereof]

It is an ester included in When diluted with water in use, such esters have a relatively low pH
It is believed that smaller silicate agglomerates are formed in the range, which in turn exhibits greater ability as compared to inorganic silicates in inhibiting metal corrosion. Furthermore, as is known for such organosilicates, any R groups selected should not sterically hinder the silicate so that hydrolysis to silanols cannot occur. Likewise, the R group that would render the silicate insoluble in the alcohol used as an antifreeze agent should not be used. Potassium and sodium silicates are suitable as examples of useful inorganic silicates. Useful organosilicate esters include alkyl silicates such as methyl silicate, ethyl silicate, butyl silicate and amyl silicate; aryl silicates such as benzyl silicate and tolyl silicate; mixed alkyl silicates such as methyl ethyl silicate; mixed aryl silicates such as benzyl tolyl silicate; mixed alkylaryl silicates. Silicates such as methylbenzyl silicate and ethyl tolyl silicate; glycol silicates such as hydroxyethyl silicate and hydroxypropyl silicate; and polyhydroxyalkyl silicates such as glycerol silicate and pentaerythritol silicate; oxyalkylene silicates such as methoxydiethylene glycol silicate,
i.e. methyl carbitol (METHYL)
CARBITOL) silicates; and mixtures of the above. A preferred organic silicate is tetrahydroxyethyl orthosilicate. Partially condensed orthosilicate esters of the well-known type are also useful. The amount of silicate in the concentrate used to make the antifreeze can vary over a wide range, but preferably ranges from 40 to 1000 ppm Si equivalent, preferably at least about 100 ppm, more preferably from 300 to 1000 ppm Si equivalent.
Present in an amount of 700ppm. Below 40 ppm there is generally insufficient silicate to minimize corrosion of metals in automotive cooling systems;
At 1000 ppm or more, gelation of silicate may occur in the antifreeze thickener and the antifreeze used. It should be understood that the amount of silicate used will depend somewhat on the PH range used. Thus, for lower PH ranges, the maximum silicate amount will preferably be at most about 700 ppm Si equivalent to minimize undesirable silicate gelation. Optional Components The antifreeze compositions that can be used with the novel compounds of the present invention can be used in the cooling systems of internal combustion engines having any metallic internal surface typically used or contemplated. Currently, many cooling systems are so-called "mixture" systems that include, in addition to iron surfaces, other metal surfaces such as aluminum. The present antifreeze compositions can be used in such hybrid systems as well as, of course, in essentially ferrous systems. In hybrids and often in ferrous systems, as with past antifreeze compositions, sometimes suboptimal corrosion resistance to ferrous and other non-aluminum metal surfaces is encountered. It is therefore preferable to use supplementary corrosion inhibitors in such systems for the particular metal surfaces involved. A wide variety of such additives are known and can be used. Additionally, such auxiliary inhibitors and other optional additives may be included as desired, regardless of the type of metal surface in the particular cooling system. In any case, they should be used in small amounts, ie up to about 50% by weight of the antifreeze concentrate, preferably not more than about 10%. Typical optional additives include, for example, known corrosion inhibitors for metals such as molybdates, tungstates, selenates, chromates, borates, organic phosphates, carbonates and bicarbonates, sebacates and other dicarboxylic acids, benzoates, hydroxybenzoates or the like. acid,
Contains acrylic acid polymers and their graft copolymers, silicones, alkali metal nitrates, alkali metal nitrites, tolyltriazole (hereinafter referred to as "TTZ"), mercaptobenzothiazole, benzotriazole, etc., or mixtures thereof. When one or more known inhibitors are used, the sum of all inhibitors is the "inhibitory effective amount," i.e., sufficient to provide a measurable degree of corrosion inhibition with respect to the metal surfaces of the cooling system to be protected. should be used in quantity. Other typical optional additives that may be used are wetting agents and surfactants, such as known ionic and nonionic surfactants such as poly(oxyalkylene) adducts of fatty alcohols; defoamers and and/or lubricants such as the well-known polysiloxanes and polyoxyalkylene glycols, as well as other minor ingredients known in the antifreeze art. Antifreeze concentrates may contain limited amounts of water, such as from about 0.1 to about 10% by weight water, based on the weight of the concentrate. The water present may be derived from commercially available alcohols often used in the manufacture of antifreeze concentrates. Antifreeze agents used as referred to herein typically include
It will contain at least about 20% water by volume based on the total weight of the antifreeze. To provide a commonly used antifreeze, the antifreeze concentrate is diluted by the addition of about 25 to about 90% water, based on the weight of the concentrate, and introduced into the cooling system of an internal combustion engine. Corrosion-inhibiting thermally conductive composition suitable for Alternatively, concentrates (which may be anhydrous) may be used as functional liquids or antifreeze agents, if desired.
Furthermore, although it is currently practiced to dilute antifreeze concentrates with water to obtain used antifreeze, it is not considered essential. Novel substituted organosilicon carboxylates and novel precursors thereof According to the present invention, novel substituted organosilicon carboxylates have the formula wherein the various symbols and values are as described above in connection with the claims of the invention. More particularly, with respect to the monovalent cation M, any of a variety of cations can be used. The main functional group requirements are that it provides solubility and that the selected component is of course ionizable. Useful examples include sodium, potassium, lithium, rubidium, and tetraorganoammonium (eg, tetramethylammonium) cations, with sodium and potassium being preferred. Regarding the R ¹ component, any of a wide variety of monovalent hydrocarbon groups can be used. A requirement for this functionality is that the selected group should not render the silane or silicone/silicate copolymer insoluble. Therefore, relatively large alkyl chains should be avoided. The hydrolyzable residue Z can be any hydrolysable group bonded to silicon, such as halogen such as F, Cl, Br and I; hydrogen; hydrocarbonoxy such as -OCH ₃ , -OCH ₂ CH ₃ , - _{OCH2CH2OH ,}
-OCH ₂ CH ₂ O-, -O (CH ₂ CH ₂ O) ₂ H, -O
(CH ₂ CH ₂ O) ₇ CH ₃ ,

【formula】

[Formula] Oximinate

[Formula] However, R is a monovalent hydrocarbon group such as methyl or ethyl), an organic amino

[Formula] Acylamide

[Formula] and haloalkoxy e.g. Chlorisopropoxy

[Formula] Hydroxyl (-OH) and siloxy including. The symbols and values in the above formula are as described in connection with the claims of the present invention. A wide variety of useful residues Z include, for example, acyloxy-containing species,
Alkyloxy-containing species, aryloxy-containing species, aralkyloxy-containing species, alkyloxy-containing species, alkyleneoxy-containing species, hydroxyalkyloxy-containing species, hydroxypolyalkyleneoxyalkyloxy-containing species, alkoxypolyalkyleneoxyalkyloxy-containing species, acyloxypoly alkyleneoxyalkyloxy-containing species, alkoxyalkyloxy-containing species, acyloxyalkyloxy-containing species, cyanoalkyloxy-containing species, cyanopolyalkyleneoxyalkyloxy-containing species, aminoalkyloxy-containing species, dialkylaminoalkyloxy-containing species,
Includes alkanolaminoalkyloxy-containing species, dialkanolaminoalkyloxy-containing species, carboxyalkyloxy-containing species, carboxypolyalkyleneoxyalkyloxy-containing species, carbalkoxy-containing species, and carbalkoxyalkyloxy-containing species. That is, there is a substantial range in the selection of the hydrolyzable group Z. The main requirement is that the selected groups do not interfere with the solubility of the silane in the alcohol used. The novel carboxylates of the present invention can be synthesized using known techniques. For example, intermediates with olefinic ends (e.g.

The conventional hydrosilylation of CH=CH ₂ is first carried out using a platinum catalyst and chlorosilane. The resulting trichlorosilane intermediate adduct can subsequently be esterified in a known manner. Continuous removal of by-product HCl may occur during the esterification step. The desired metal carboxylate is then obtained using a base such as sodium hydroxide, potassium hydroxide, sodium methoxide in methanol. The amount of base used is determined by the amount of metal carboxylate expected in the final product. The amount of base used can range from the amount needed to neutralize any remaining Si-Cl to the amount needed to convert the alkyl carboxylate to the metal carboxylate. An excess of base over the amount necessary for conversion to the metal carboxylate may also be used. Synthesis of carboxylates containing alkyleneoxy residues can be performed using known techniques. For example, a base-catalyzed polymerization of an alkylene oxide is first carried out using an initiator such as allyl alcohol. After termination with an acrylate (eg ethyl acrylate), conventional hydrosilylation is carried out. Further processing is then performed as described herein. According to the invention, a formula that can be hydrolyzed or saponified to give the desired carboxylate Useful substituted organosilicon carboxylates can be derived by using precursors of . The symbols and numbers in the formulas herein are the same as those described in connection with the organosilicon carboxylates of the present invention. Examples of useful residues for Y include

【formula】

[Formula] N=C-,

【formula】

【formula】

【formula】

【formula】 as well as

[Formula] and M is an alkali metal. Other similar groups that are hydrolyzable or sufficiently saponifiable to carboxylate bases may also be used. For many of the precursors, the alkoxy intermediate can be converted by conventional transesterification. For cyano and amide precursors, cyanoolefin compounds can be used. These compounds can be subsequently converted using hydrosilylation as described above. The amide precursor is then obtained by hydrolyzing the cyano precursor. As can be seen, the end of a substituted organosilicon carboxylate molecule that can be hydrolyzed to a silanol is
Upon reaction with the silicate used, a copolymer, as commonly termed in the art, is produced. It is therefore particularly suitable to utilize carboxylates or precursors thereof which give silane triols upon hydrolysis. In other words, it is particularly preferred to use carboxylates in which c is O in the structural formulas shown herein. It is further believed that the active species for corrosion protection are monomeric silicates. Therefore, superior performance results and optimized effectiveness can be provided by using systems with less chance of forming undesirable and inert silicate polymers. Achieving this objective requires the use of silanes that can effectively stabilize the silicate species that generate the silicate monomers. One aspect of this is that the monomeric silane triol species may be primarily and preferably entirely in monomeric form, or if in polymeric or low polymeric form, during the preparation of the antifreeze concentrate, upon addition of base and alcohol. using a silane starting material that can be selectively and rapidly reverted to In other words, the formation of irreversible silane polymers reduces the stabilization efficiency of the silane by reducing the number of molecules present for reaction with the silicate, leading to the formation of undesirable precipitates. Close. Another aspect is to preferably use a soluble silane starting material in the antifreeze concentrate (where the concentrate appears clear to the naked eye). In this preferred embodiment, the soluble silane disperses rapidly into the alcohol component, and it is advisable to avoid localized relatively high concentrations of silane, which may result in undesired polymerization occurring more easily. Therefore, when using a carboxylate precursor, the Y residue used must be a carboxylate precursor that can be easily dispersed therein and readily provides solubility, if not confers solubility in the concentrate of the silane. It is necessary that it can be hydrolyzed or saponified. According to the most preferred embodiment of the invention, the substituted organosilicon carboxylate is in glycolized form.
It has been discovered that optimal performance is obtained using glycolized forms of antifreeze. As an example to obtain the glycolized form, hydrosilylation is first carried out by using a platinum catalyst and chlorosilane: It is then reacted with an excess amount of ethylene glycol (or any of the other alcohols described herein) to ideally The glycolized form is prepared by obtaining. Glycolation reaction products generally remain in small amounts
Since it contains Si-Cl, it may be desirable to neutralize the reaction product with a base. Since the presence of water promotes polymerization of the silane, it is more desirable to use an anhydrous base such as solid sodium methoxide in methanol. However, KOH etc. can also be used.
The amount of base used can range from that needed for neutralization to the amount that converts the glycolated carboxylate end of the molecule to the metal carboxylate. The main species obtained (relative amounts depending on the degree of neutralization) are

[Formula] and Will. When producing antifreeze concentrates by addition to base and alcohol, the aforementioned precursors are active species, i.e.

The reaction products of the precursors are generally also present in varying amounts. Complete conversion to the active species can be achieved by complete saponification during the synthesis. It should be understood that this is an idealized structure and some amount of silane polymer will be present. The amount can be determined by using ²⁹ Si nuclear magnetic resonance. Other methods may be used to generate the glycolized form. Many methods are known for this. The use of glycolized forms appears to provide optimized performance. The extent of silane polymer formed is thus minimized and the tendency to form undesirable precipitates (either due to insoluble silane polymer or insoluble polymer upon reaction of the silane polymer with the silicate) is substantially reduced. decreases to Furthermore, although I do not want to be bound by any particular theory,
The more useful substituted organosilicon carboxylates of this invention are believed to be characterized by a suitable glycolophilicity/glycophobicity balance as well as satisfactory molecular weight. Without proper molecular weight and balance, organosilicon carboxylates appear to tend to destabilize silicates in the antifreezes used. This destabilization is evident by the formation of gel within the cold pole system of the vehicle. These gels, in turn, clog the radiator tubes of the cooling system and, importantly, aggregate the silicates, rendering them inactive as metal corrosion inhibitors. It is envisioned that the above balance is necessary to provide what is termed a suitable driving force that effectively increases the likelihood that the organosilicon carboxylate will reach the silicate to give the desired copolymer. The result is determined as negatively charged silicate particles (silicates are considered to be microcolloidal in shape), thus the particles are stabilized in the antifreeze. Considering the molecular weight, silane molecules that are too low have a greater potential to homopolymerize, thus starving the stabilizer and resulting in a loss of control in silicate chemistry. It seems that it will be. More particularly, in the absence of suitable stabilization, silicate particles grow excessively to undesirable sizes. The function of stabilization is to at least minimize and preferably eliminate excessive silicate particle growth which ultimately reduces the amount of active monomeric silicate species present in the antifreeze used. On the other hand, a molecular weight that is too high will give a molecule that contains what can be described as excessive bulk. This would tend to disturb the kinetic equilibrium or actually produce insoluble non-equilibrium products, unsatisfactorily reducing the required solubility. Generally, the proper balance to provide the desired driving force is beneficial in that achieving this proper balance likewise results in the proper molecular weight for both the silane stabilizer and the resulting silicone/silicate copolymer. It was discovered that In other words, carboxylate silicones with excessively short chain lengths can be expected to produce high molecular weight homopolymers. In contrast, longer chain length silicone carboxylates have an inherent bulk that limits the extent of homopolymerization. However, when silicone carboxylates of excessive chain length are used and homopolymerization is minimal, undesirable precipitation of the silicate copolymer in the antifreeze used becomes a major concern. The appropriate balance and molecular weight of the polymer can be determined in a simple manner. In particular, the "boiling beaker" test (described below) may be used to measure precipitation during this test. Of course, it is most preferred that essentially no precipitate forms in the boiling beaker test. Performance of one that meets that criteria should provide a very stable antifreeze. Indeed, using the most preferred embodiment of the invention, approximately 10
Only less than mg of precipitate is produced. The use of the antifreeze compositions of the present invention will also provide improvements in this regard in relation to antifreeze compositions using other silanes. Therefore, the use of organosilicon carboxylates of the present invention produces only 60 mg or less of precipitate. According to a preferred aspect of the invention, organosilicon carboxylates are used in which in the above formula a is 0, b is 1, c is 0, m is about 7 to 15, and M is potassium or sodium. . Most preferably m is 10 and a, b, c and M are as described in the preferred embodiments. Other useful carboxylates include a between about 5 and 13 (more preferably between about 5 and 13).
approximately 9), b is 1, c is 0, n is 2, and m is 3
It can be shown according to the formula. From the standpoint of known synthesis technology, a is 0 in the formula
Otherwise m will be either 3 or 4. Therefore, and in order to give a conceptually optimal glycolic (hydrophilic)/glycolic (hydrophobic) balance, an alkyleneoxy moiety containing, for example, synthetically derived (CH ₂ ) ₃ groups, i.e. -(C _o H _2o O) _a should be equal for a compound with an additional CH ₂ chain length of 7 from a balance standpoint. As is also known, the character of the alkyleneoxy chain becomes more hydrophobic with larger alkyleneoxy groups. More particularly, propyleneoxy groups are relatively more hydrophobic than ethyleneoxy groups. In a more general sense, when a is other than 0 and thus one or more alkylene oxy groups are present, suitable compounds have the same glycolic affinity as that given when a is 0. (hydrophilic)/glycophobic (hydrophobic) balance, ie, the same balance as having about 7 to about 15 methylene chains. More particularly, the balance properties of propyleneoxy residues appear to be essentially the same as those of methylene residues. Thus, when 3 methylene chains are derived from the synthesis, about 4 to 12 propyleneoxy chains should provide useful material. In all ethyleneoxy systems with three methylene chains from synthesis, an average of 7.5 ethyleneoxy chains has a degree of hydrophilicity slightly greater than the optimum. Approximately 5 ethyleneoxy chains should provide a suitable balance. Also, and generally, it will be desirable to use approximately two ethyleneoxy groups to one methylene group (in all methylene systems) to obtain a molecule with the desired balance. This same general relationship is true for the ethyleneoxy-propyleneoxy system. All butyleneoxy systems tend to be somewhat more hydrophobic than molecules with only methylene groups. In this system, as well as in other alkylene oxy systems, the suitability of the balance for a particular case can be easily determined by simple experimentation, ie, by synthesizing the compound and boiling beaker testing. The above description is based on the use of essentially linear aliphatic compounds. However, it should be understood that branched compounds can be used, as well as the introduction of aryl groups, if desired. The suitability of such substituted compounds can be determined using the boiling beaker test as described herein. It should be understood that the silane carboxylates of the present invention are most preferably synthesized in a manner that maximizes the amount of run monomer and minimizes the amount of silane low polymer that may be formed. . In particular, two silane monomers react to form Si-O-Si.
It may form a low weight polymer with bonds, or three and more molecules may react to form higher weight polymers.
It is the higher, lower weight forms that are to be avoided, as the silane dimers will ultimately revert to monomers, at least in large part, upon addition to the alcohol. Maximization of silane monomer is achieved by avoiding the presence of water during the synthesis. The carboxylates of the present invention can optionally be placed in an excess of alcohol, such as ethylene glycol, to further minimize the formation of undesirable underweights. The desired product is therefore a base in an amount ranging from that needed to neutralize any residual Si-Cl from the synthesis to an amount adequate to convert the carboxylate to the metal carboxylate. comprising the glycol form described herein with added . The amount in alcohol in glycol form is approximately 20% as desired for the application.
It may range from as little as 75% by weight or less. Amounts of active species of about 50-75% by weight are considered more desirable. The total silicone portion of the silicone/silicate polymer used, of course in an effective amount to stabilize the amount of silicate used, preferably ranges from about 10 to 100 ppm silicon equivalent based on the weight of the antifreeze concentrate, more preferably about It is used in amounts corresponding to 25 to about 100 ppm. Generally silane is about 10 (by weight) of silicone
It is desirable to use it in an amount of %. however,
The amount can be varied as desired consistent with desired economic and performance requirements. Silicone/Silicones made by mixing silanes and silicates useful in the compositions of the present invention
Preferably the silicate polymer is from about 0.01 to about 10% by weight, based on the weight of the concentrate, more preferably about
0.05 to about 5% by weight, most preferably about 0.05 to about 3% by weight
Used in amounts of % by weight. Below about 0.01% by weight, this amount of silicone/silicate is expected to be insufficient for functional protection against metals, while about 10%
Above a weight percent, the silicone/silicate cost becomes excessive. The polymers useful in this invention can be pre-prepared prior to antifreeze formulation, or they can be incorporated into antifreeze formulations by mixing with silicate in the presence of an alcohol using an organosilane. It may be generated on the spot. Suitable methods are well known in the art and are disclosed, for example, in US Pat. Nos. 3,337,496 and 3,312,622, which are incorporated herein by reference. Performance of Antifreeze Concentrates Antifreeze concentrates by using the novel organosilicon carboxylates (and their precursors) of the present invention are characterized by satisfactory stability against gelation before use. When preparing antifreezes for use in dilution, the use of these antifreeze concentrates is characterized by an exceptional resistance to gelation and no formation of undesirable precipitates. The relative amount of active monomeric silicate present in the antifreeze used should likewise be maximized. In other words, the improved stability resulting from the use of the novel organosilicon carboxylates of the present invention substantially reduces, perhaps even essentially, the formation of inert polymeric silica in particularly preferred embodiments. It should give the ability to exclude. The present invention provides additional advantages when an optional corrosion inhibitor is used in the formulation. Thus, the introduction of optional ionic inhibitors tends to worsen the solubility and stability aspects of the system, especially at low PH values. Antifreeze compositions using the novel organosilicon carboxylates of the present invention, which impart superior stability to the antifreeze used, provide less sensitive and more efficient systems. Indeed, the given high quality should provide greater freedom in formulations than was hitherto possible. Other Applications The previous description has illustrated the use of the novel organosilicon carboxylates (and their precursors) of the present invention as stabilizers in silicate-containing antifreezes. In such applications, the novel compounds of the present invention are believed to have substantial utility and confer highly desirable performance properties. however,
It should also be understood that these new organosilicon carboxylates may be utilized in any other applications where their properties are useful. For example, as described in US Pat. No. 4,370,255, silanes are useful for stabilizing aqueous silicate compositions for use in suppressing school in heat exchange systems, geofuel power plants, and the like. Other similar applications include the treatment of metals to provide protective coatings. Still other uses include those described in US Pat. No. 4,157,978. The silanes of the invention can be used to stabilize silicates used in the detergent field. Further applications include silicate-containing drilling materials used for oil recovery.
(mud) stabilization. Other uses for silanes include U.S. Patent No. 3,816,152
silane used as a coupling agent, with a silicate to chain-extend it. Somewhat similar applications include the preparation of silicone/silicate copolymers to formulate sizing agents and the like to impart improved properties to various glass fiber composites. Such copolymers can also be used to treat a variety of fibers used in a variety of applications. Silanes are also useful for stabilizing silylated organic polymers. Particles of such organic polymers in water-based systems may thus use silane stabilizers. Thus, the novel carboxylates of the present invention have utility as novel silicone/silicate copolymers for several applications. These new copolymers can be made in a wide range of proportions, depending on the intended use. That is, the weight ratio of silane:silicate can vary from about 0.1:99.9 to about 99:1, with a weight ratio of 1:99 to about 99:1 perhaps being more preferred. The silicate used will depend on the application and economics used. However, the silicates used may generally be any of those described herein. The following examples are merely illustrative and are not intended to limit the invention. Example 1 This example illustrates the preparation of a preferred class of intermediates for the carboxy-substituted organosilicon stabilizers of the present invention. In a three-necked flask equipped with a thermometer, magnetic stirrer, distillation tower with receiver, and electric heating mantle,

[Formula] 130.0g (0.40mol), HOCH ₂ CH ₂ OH198.6g (3.2mol) and 85
0.5 g of %KOH pellets (15% _H2O ) were charged.
This stirred mixture was heated from 79°C to 149°C for 6 hours.
℃, during which time 49.6 g of methanol distillate (theoretical amount of 51.3
%) was collected. Product residue (279.5g) was heated to ^13C
NMR analysis confirmed complete exchange of methoxy groups. Mainly in ethylene glycol A clear solution of 77.4% by weight was produced. This intermediate can then be converted to the metal carboxylate by treatment with base. For example, this conversion reaction may be carried out by reaction with sodium methoxide, suitably in methanol. Suitable conditions are to heat the mixture for 2 hours at 100%
Including heating to ℃. Example 2 This example illustrates the selection of various types of silanes in stabilizing silicates in aqueous (50% by volume) antifreeze under elevated temperature test conditions. A standard base solution for formulating each antifreeze concentrate was prepared as follows. Basic liquid A ^* Ingredient weight% ethylene glycol 93.5062 Na ₂ B ₄ O ₇・5H ₂ O 3.7200 NaOH, 50% aqueous 1.4745 Sodium silicate, 40% clear ^** 0.3663 NaNO ₃ , 40% aqueous 0.5000 Sodium tolyltriazole 0.2330 Water 0.2000 Total Weight% = 100.0000 * PH of base liquid, 50% by volume aqueous = 8.7 ASTM Reverse Alkalinity (RA) = 56.6 ** Manufactured for applications requiring solids content of 38.3% by weight and high transparency. Diamond
Shamrock Corp.) liquid sodium silicate products. Each silane, as shown in the table below, was added to Base Liquid A in an amount sufficient to provide 45.2 ppm Si in the Base Liquid A concentrate. Prior to addition to Base Liquid A, each silane was saponified with the number of moles of potassium hydroxide specified in the table. This saponified silane ester has a specific number of moles of KOH.
Prepared as a 25.8% by weight solution. The remainder was added by volume as a mixture of 1/3 ethylene glycol and 2/3 deionized water. The saponification method used was as follows: 1. Silane, ethylene glycol and water were weighed into a suitable container. 2 Add the specified amount of KOH and stir with a magnetic stirrer until dissolved. 3 The resulting solution was poured into a glass bottle, the weight was recorded, and the solution was loosely covered and placed in an oven at 100°C. 4 After 16 hours at this temperature, the solution was brought up to its original weight with water to replace evaporation losses and mixed well to produce a saponified silane. The "boiling beaker test" was used to mimic the high test temperature conditions experienced by automotive antifreeze in the laboratory. This test is for 100ml of antifreeze concentrate
was placed in a 300 ml Pyrex beaker and 100 ml of deionized water was added to the beaker. The beaker was then covered with a watch glass and equipped with a magnetic stirrer. The aqueous antifreeze in the beaker was heated to 108°C for 1 hour until boiling.
The aqueous antifreeze was then cooled to room temperature and the resulting precipitate was washed with deionized water and dried to constant weight in a 180° oven. The weight of the dried precipitate is reported in the table as mg of solids. The test results are presented in the table.

Table 1 The results shown in Table 1 demonstrate that silane (D), the preferred species of organosilicon carboxylate of the present invention, is particularly effective compared to the other silanes tested.
Comparison with (F) and (F) shows that it has exceptional silicate stabilization ability. This superior performance is readily apparent, especially on the basis of the lower sediment weight of formulations containing silane (D) compared to the sediment weights for the structurally similar silanes (B), (C) and (E). . The carbon chain length of the silane (D) is optimized for glycolophilic (hydrophilic)/glycophobic (hydrophobic) silicone/silicate polymers in both antifreeze concentrates and diluted aqueous antifreezes. ) seems to provide balance. Example 3 This example illustrates the differences in the silicate stabilizing ability of various silanes in an aluminum disk test using a cold finger. This example results from a different and less severe test environment than the boiling beaker test shown in Example 2. Standard test methods used in the antifreeze industry were used to determine the inhibition results of formulated antifreeze compositions for various silicones on heat rejecting aluminum surfaces. This test method is described in "Laboratory Method for Determining Corrosion Rates under Heat Reflux Conditions" in Corrosion, 15257T in 258T (1959), which is incorporated herein by reference. Also, a symposium sponsored by ASTM Committee D-15 entitled “Engine Refrigerant Testing: State of the Art”
It is described on pages 17-19 (May 1980, ASTM Publishing). The following is a summary of the test equipment and techniques used: The equipment consists of a condenser, a thermometer, a cold finger, a temperature regulator, a 1 1/2 inch diameter x 1/4 inch thick cast aluminum 319 alloy (herein referred to as "aluminum"). 1 with a soldered iron heat source
It came from a flask. An antifreeze solution diluted with water (antifreeze/
900 ml of water (volume ratio: 1/3) was charged and heated on the surface of an aluminum disk until it boiled, maintaining the solution temperature at about 80°C. Each water diluted antifreeze solution was prepared by adding silane to Base Liquid B as shown in the table below.

【table】

Table: Silane was added at a concentration of 0.1% by weight based on the total weight of base liquid + silane. When described as saponification in the table, the saponification method shown in Example 2 was followed. The test period was 168 hours. The weight loss from aluminum discs of aluminum was determined and served as a measure of the effectiveness of the corrosion inhibitor expressed in % inhibition. The results are shown in Table 1.

TABLE As can be seen from the table, saponification to give organosilicon carboxylates shows improved performance compared to the unsaponified compounds used. That is, although saponification occurs at least in part due to the water present in the base liquid used, saponification prior to addition of the base liquid improves the performance of test number 2 (unsaponified) according to the present invention in test number 3 (saponified).
This can be determined by comparing it with that of . Additional aluminum plate tests were conducted using the base fluids shown in the table. The silane used was
Si was incorporated into the formulation at 45 ppm. The results of the aluminum disk test are shown in the table:

TABLE Results show that saponified C ₁₀ carboxylates, which are the preferred species of the present invention, as measured by low amounts of cold finger deposits of less than 0.1 mg, with respect to minimizing silicate destabilization. Showing outstanding performance of silane (Test No. 17). The cold finger deposits were analyzed to be essentially all silica deposits. The identification data of the compounds of the present invention shown in Examples are as follows. NMR analysis average composition mole% of ¹³ C and ²⁹ Si K ^+- OOC (CH ₂ ) ₁₀ Si (OH) x (OK) _3- x 14±2 K ^+- OOC (CH ₂ ) ₁₀ Si (OH) x ( OK) _2- x (O1/2) ₁
61±2 K ^+- OOC (CH ₂ ) ₁₀ Si (OH) x (OK) _1- x (O1/2) ₂
25±2 K ^+- OOC (CH ₂ ) ₁₀ Si (O1/2) ₃ 3±2 Measured physical properties Appearance Amber transparent odor Weak specific gravity (25/25℃) 1.23 Flash point (Seta-closed cup, 〓)＞125 Chloride Physical ion (meq/gm) <0.01 Freezing point (℃) -20

Claims (1)

[Claims] 1 formula [wherein a is 0, b is 1, c is 0, n is an integer from 2 to 4, m is 10,
M is a monovalent cation selected from sodium and potassium, R ¹ is selected from the group consisting of hydrogen, monovalent hydrocarbon groups and substituted monovalent hydrocarbon groups, and Z is hydroxy or -OCH _{3 , -OCH2CH3 , -OCH2CH2OH , -OCH2CH2O-} and _-O ( _CH2CH2O ) _2H ] .