US3429909A - Secondary aminoalcohol-boric acid reaction product and production thereof - Google Patents

Description

Feb. 25, 1969 D. scHusrER 3,429,909

SECONDARY AMINOALCOHOL-BORIC ACID REACTION PRODUCT I AND PRODUCTION THEREOF 1 1 I 1 l I I I I l T I l l l I I I l l I I l I I I /234557di/0///2/3/4/5/6/7/.5/y2a2/2223w2525272d2y @ff/az, Na/ML FIG.I

IN V EN T 0R. /Er/P/r/f 5a/afrik? BYUM/Lgr Feb. 25, 1969 D. scHusTr-:R 3,429,909

SECQNDARY AMINOALCOHL'BORIC ACID REACTION PRODUCT AND PRODUCTION THEREOF Filed April 25, 1966 Sheet Gowuom umm Sheet I 3 of 5 Feb. 25, 1969 D. SCHUSTER SECONDARY AMINOALCOHOD-DORIC ACID REACTION PRODUCT AND PRODUCTION THEREOF Filed April 25, 196e United States Patent O 2 Claims ABSTRACT F THE DISCLOSURE Boronand nitrogen-containing reaction product is obtained by reacting boric acid and a secondary aminoalcohol, and then reacting the resulting product with a carboxylic acid, under specified conditions. Products are bacteriocidal, non-corrosive and biodegradable, and can be dissolved, dispersed or emulsied in water.

The present application is a continuation-in-part of my prior application Serial Number 413,366, filed November 23, 1964, now abandoned, and entitled Rust Preventing, Wetting and Emulsifying Agent.

The present invention relates to compositions, and to a process for the manufacturing of such substances, which are bacteriocidal, non-corrosive, act as wetting agents, and are bio-degradable upon dilution with water. The new compositions are particularly useful as cooling and lubricating agents, for example, as cutting fluids in the metal working industry, but also have desirable cleaning properties and can thus be used as detergent concentrates.

Recently, efforts have been made to improve the working of metal, particularly metal cutting and metal forming, by better cooling and lubrication. Synthetic substances, based on water as a coolant have decided advantages over hydrocarbon or oil derivative products. The cooling properties of water are far superior to those of other products, particularly when the surface tension of the water is decreased by the use of wetting agents. Water alone is however not useful due to its corrosive action, particularly when known wetting agents have been added, as well as due to its lack of lubricating effectiveness.

Various proposals have been made to develop cutting uids based on water by use of additives. For example, soaps added to water have been used, particularly soaps which are derived from amino alcohols, with additives of higher sulfonated, or unsulfonated fatty acids or naphthenic acids, or from carboxylic acids, obtained from the oxidation of hydrocarbons.

The use of ethanolamine based soaps is particularly advantageous because, in a watery solution, a pH value of above 9 is readily obtainable, and thus they do have some corrosion inhibiting effect. The corrosion inhibiting effect can be increased by adding other acids or salts, in order to increase the buffering action. Additives described in the literature include, for example, alkylsulfoneamidocarboxylic acid, and its salts; and boric acid and its salts.

The corrosion resistant effect of such aqueous cooling and lubricating substances is further improved by adding sodium nitrite which is recommended as an additive for almost all aqueous products. Unfortunately, sodium nitrite is extremely poisonous. In actual practice, sodium 3,429,909 Patented Feb. 25, 1969 ice nitrite is usually added in quantities of from l to l0 percent to the concentrates used for cutting liuids. From the point of view of the health of the worker at the machine, in which the fluids are used, this is an undesirable additive. The lethal dosage for an adult human is only four grams of sodium nitrite. Lethal poisonings in adults are observed primarily in connection with food and food preservation; nevertheless, cutting uids used on the machines do leave a spray or a mist from time to time which are inhaled by the machine operators and may cause anaemia and low blood pressure, as well as damage to the blood circulatory system, and even in small doses may cause or contribute to liver damage due to the formation of nitro compounds.

Known substances, in many variations and in combinations with bulfering agents and sodium nitrite as a corrosion inhibiting agent, have substantial disadvantages, entirely apart from the poisonous aspect of the sodium nitrite itself. One of these disadvantages is that fatty acids used in such soaps form salts which are difficult to dissolve in combination with alkali metals, and may cause precipitates which eventually cloud the solutions or result in scum; at its worst, they may interfere with the disposition of the colloidal solutions themselves. Therefore, and in order to stabilize such precipitates, various proposals have been made to stabilize such aqueous solutions. One of such proposals is to add a non-ion forming emulsifier, in order to disperse the difcultly soluble calcium salts. These non-ionic emulsiers or wetting agents are, chemically, condensation products of alkyloxides with various organic substances, for example polyetheralcohols, fatty alcohol polyglycolethers, fatty acid amido polyglycolethers or fatty acid polyglycolesters. Typical examples are: octylphenylpolyetheralcohol mixed in with the above-identified substances; a non-ion forming condensation product derived from amines with ethylene oxide; and a monobutylether of a condensation product of an alkyloxide with ethanolamine.

The above described mixtures have good wetting and dispersion properties and also impart good corrosion resistance. Further additives are used in order to increase the lubricating effectiveness to provide for bacteriocidal and fungicidal effect and to prevent foaming. Non-aromatic oil distillates are often added in order to improve the lubricating effectiveness. In order to provide for bacteriocidal and fungicidal properties, and particularly in order to suppress the growth of anaerobic bacteria, additives consisting of phenol, cresol, or triazine derivatives are used, or highly antiseptic chlorine compounds. Yet, bacteriocidal and fungicidal additives at times contribute to dermatological disease. Some investigators, active in industrial medicine, regard these additives as a most usual cause of industrial dermatosis. Entirely apart from the susceptibility of several operators to these additives, they are undesirable because they inhibit the growth of bacteria not only in the material itself, but also in settling tanks and in the streams and rivers to which industrial wastes are often, unfortunately, conducted, since they prevent biological degradation and cause pollution.

The compositions according to the present invention are inherently not poisonous. Thus, they have the property of bacteriocidal and fungicidal effect in the concentrations used in the metal working industry; these bacteriocidal and fungicidal effects are lost, however, when the compositions are diluted to the extent customary in a settling tank. Upon such substantial dilution, they become biologically degradalble. Further, the compositions of the present invention have insecticidal and insect repellent effects so that not only the agents causing decomposition and dermatosis are inhibited, but the carriers of bacteria, that is primarily flies, are not found in the environment where the new compositions are used. Nevertheless, the compositions are non-toxic to humans and do not cause skin irritations.

It is an object of the present invention to provide compositions which are bacteriocidal and non-corrosive and which have the desirable lubricating properties of oilbased cutting uids while retaining the desirable cooling properties of Water-based cutting fluids, without any of the disadvantages of either fluid.

It is further an object of the present invention to provide cutting fluids which are medically acceptable to the operator of the machine on which the uids are used, that is fluids which are bacteriostatic, fungicidal and yet non-poisonous. It is a further object of the present invention to provide a metal working fluid which is Ibiologically degradable so that it will not present disposal problems but may be discharged into public rivers and streams without causing pollution or endangering fish or plant life.

It is yet another object of the present invention to provide compositions which have detergent and cleaning properties, are readily soluble, bacterie-static, and yet biologically degradable when sufliciently diluted.

Briefly, in accordance with the present invention, at least two molar proportions of a secondary aminoalcohol are reacted with one molar proportion of boric acid (H3BO3) or are -analog thereof (preferably 3:1 to 5:1) at a temperature varying from about 130 C.; water formed in the reaction is removed from the resulting reaction system, whereby a boronand nitrogen-containing reaction product is obtained. This reaction product can then be reacted with a carboxylic -acid at a temperature of from about 150 C. to about 230 C., With water being again removed from the reaction system, whereby a -bacteriocidal, non-corrosive, boronand nitrogen-containing reaction product is obtained. The latter reaction product is also a wetting agent and is characterized by the propcrty of being biodegradable when diluted with a substantial quantity of water.

The yreaction of the aminoalcohol with the boric acid may be done in the presence of glycols in the range of from 0.1 or less, to about molar proportions of the glycol for each molar proportion of aminoalcohol. The product thus obtained is less viscous, easier to dilute with water to a working cutting fluid solution and, by suit-able choice of the glycol, provides smoother cut surfaces when used as a cutting uid in a machine tool operation.

As indicated, molar proportions of secondary aminoalcohol -and boric acid and reaction temperatures are important factors in the production of the desired reaction products. The exact composition of the said products is not fully clear at this time, such that exact chemical formulae/ cannot be ascribed to them. However, it appears that -by careful control of reaction temperature within the ranges given above, and by using certain acids, it is possible to form piperazine compounds and to isolate the same from the remainder of the reaction products. This represents a further embodiment of the present invention. Reaction temperatures are controlled to from `about 160 C. to about 230 C., and saturated or unsaturated carboxylic acids having a chain length of C12 to C22 are used in the reaction of aminoalcohol, preferably diethanolamine, and boric acid. This is illustrated below in the examples.

Water is formed in the initial reaction stage between a secondary aminoalcohol and boric acid. For each mol of boron compound used, at least one and not more than three mols of water are formed. And water is also formed during the second reaction stage in which Ia carboxylic acid participated. It is a characteristic of this second stage that there is formed at least one mol of water for each mol of fatty acid charged.

As contemplated herein, analogs of boric acid include: HBO2, H2B4O7 and B203, as Well as their corresponding salts, esters and halogen compounds. Preferred, however, is boric acid (H2BO3).

Aminoalcohols used herein are represented by the general formula wherein R and R' are either the same or different bivalent aliphatic groups (-CH; CH2-CHF, ete), which may have one or more side chains or substituents therein. Preferably, the length of the chains R and R' are similar and contain from 1-6 carbon atoms. Typical compounds are diethanolamine and diisopropanolamine. Particularly preferred is diethanolamine.

It is also contemplated that a tertiary aminoalcohol, as triethanolimine, can also be used together with a secondary aminoalcohol. In all such instances, the secondary compound is used in greater quantity than the tertiary compound.

Carboxylic acids of a wide variety can be used in forming reaction products coming within the framework of this invention. The acids can be saturated or unsaturated and contain at least about 8, preferably from about 12 to about 22, carbon atoms per molecule. Typical acids are lauric, myristic, palmitic, stearic, oleic, and all oil acids, naphthenic acids and phthalic acid. Generally, from about 0.5 to about 3 molar proportions of carboxylic acid are used per molar proportion of boric acid.

The invention is illustrated by the following examples.

Example 1 Production of an intermediate reaction product containing boron and nitrogen is illustrated by this example.

945 g. (9 mols) of di-beta-hydroxyethylamine (diethanolamine) are mixed at a temperature of about C. with 122 g. (2 mols) of pulverized or `granular boric acid (H3BO3) in a retort of about 2 liter capacity. The retort is connected with a descending cooler and provided with an electrical mixer. Mixing is continued until the entire boric acid is dissolved. Thereafter, under strong heating, a condensation reaction is started, which begins at a temperature of about C., at which the reaction mixture begins to boil and water is split off. The water of reaction is collected in the descending cooler in a measuring vessel. With a period of about 45 minutes to one hour, the temperature of the reaction mixture is raised to a temperature of about 230 C., and about 100 to 108 ml. of water is formed and is distilled off. This corresponds to approximately 6 moles of reaction water; that is, approximately 3 mols of water are obtained per mol of boric acid.

Thereafter, the reaction mixture is subjected to vacuum distillation in order to determine how much di-beta-hydroxy-ethylamine are obtained, having a boiling point of about -165 C. This indicates that the condensation reaction according to the example provides a composition in which one mol boric acid has reacted with two mols of di-beta-hydroxyethylamine.

The reaction product obtained after the vacuum distillation is a clear, honey-colored substance which, as it cools, becomes glassy. If this substance is heated to the point of just melting, and stirred with a glass rod, the crystalline form of the reaction product is obtained.

The product showed the following analytical composition (carbon and hydrogen determination according to Liebig):

Carbon, 42.1-42.5 percent,

Hydrogen, 8.8-9 percent,

Nitrogen, 11.7-12 percent (Dumas); 12.2 percent (Kjeldahl),

IBoron, 4.5-4.8 percent (determined as boric acid after saponitication with hot, fuming hydrochloric acid).

Example 2 1260 g. (12 mols) of di-beta-hydroxyethylamine (diethanolamine) are mixed with 244 g. (4 mols) of boric acid in powder or granular form in a 2.5 liter retort, provided with a heating jacket, a distillation head and a descending cooler, and an electrical stirring mechanism. Mixing temperature is about 100 C. and mixing is continued until all of the boric acid is dissolved. Thereafter, the condensation reaction is started under substantial heating as in Example 1, which reaction begins at about 130 C. Water is split off. The Water of reaction is condensed over the descending cooler and collected in a measuring vessel. As before, in about 45 minutes to one hour the reaction temperature is raised to about 230 C., and about 210 to 216 ml. of Water are split and distilled off. Thereafter, heating is discontinued and the reaction mixture is permitted to cool to a temperature of about 160 C. Heating is commenced again and at the same time 280 g. of tall oil (a mixture of fatty acids) at a temperature of 160 C. are added to the reaction mixture, for example through a separate tube. Mixing is started rapidly in order to provide for quick intermingling of the substances in the retort. After addition of the tall oil, the inlet through which it was added is closed. When the mixture reaches 180 C., the second step of the condensation reaction starts. Within a period of about two hours, 65 to 72 m1. of water are split off. The temperature should not exceed 230 to 240 C.

The thus obtained reaction mixture is permitted to cool to a temperature of about 80 to 120 C., and is then poured into a vessel containing 1350 g. of distilled water. The reaction mixture and the water are mixed and a thick honey-like liquid, similar to an emulsion and having a pleasant smell, similar to esters, is obtained. A nonaromatic hydrocarbon fraction, in accordance with the 4following specilication, is added to this emulsion under constant stirring, until a completely clear viscous, yellow, pleasantly fruity smelling liquid is obtained. For complete clearing of the solution which is initially similar to an emulsion, 80 to 160 g. of the hydrocarbon are necessary.

Specification of the hydrocarbon fraction is: specific gravity, C., 0.805; boiling point: 244-332D C.; refractive index, 1445; ash point, 106 C.; iodine number, 0.03; aniline point, 91 C.

Instead of this hydrocarbon fraction, other mineral oil fractions, glycols, polyglycols, fatty acid amides, polyesters, polyethers, silicones, or other substances which are capable of changing the emulsion to a clear liquid with an addition of at the most percent of such material, may be used.

The concentrate according to Example 2 is completely soluble in any proportion with water, remains clear, hardly foams, and does not form precipitates with hard water. It is an ideal cooling-lubricant-and detergent concentrate which can be used, diluted in water, up to 0.05 percent.

Example 3 First reaction step: the rst reaction step is carried out as in Examples 1 and 2, reacting: 630 g. diethanolamine (6 mols) and 122 g. boric acid, H3BO3 (2 mols); with formation of 108 g. water (6 mols).

Second reaction step: the second reaction step is carried out as in Example 2, lauric acid (200 g.; l mol) is added. Water of reaction split oft" comprised 54 g. (3 mols).

The reaction product is soluble in water, is clear, and has strong wetting properties. Preferably it is thinned in a proportion of about 1:1 with distilled water and forms a clear, water-soluble, cooling, lubricating and detergent concentrate. In order to improve the buffering action, two percent of the hydrocarbon described in Example 2, or

6 an organic or inorganic acid with a dissociation constant of less than 5 10-4 can be added.

Example 4 First reaction step: as in Example 3.

Second reaction step: similar to Example 3, however, utilizing 288 g. of myristic acid, during 20 minutes and at a temperature of 225 C. 58 g. of Water (3.2 mols) are condensed out.

The reaction product thus obtained is soapy and solid. When heated and thinned with distilled water in the proportion of 1:1, it is a stable emulsion which can be further diluted with water. The product, diluted with water 1:1, has good cooling, lubricating, and detergent properties, and good corrosion inhibiting effects.

A clear, water soluble product, can be lmade by adding (in parts by weight): 90 parts of the product diluted 1:1 in the above Example 4; 25 parts oil and 10 parts fatty acid polydialkylamide.

Example 5 First reaction step: as in Example 3.

Second reaction step: addition of 256 g. (l mol) of palmitic acid at 200 C., within thirty minutes; and condensing otf 58 g. (3.2 mols) water.

The product has a soapy character, and is soluble in water up to C. giving a clear solution. At further cooling, the substance becomes a stable pasty emulsion, which can be diluted further as a cooling, lubricating or detergent substance.

In order to make the product easier to handle, a stock solution thinned with water, 1:1, may be mixed with 70 parts (by weight) of oil.

Example 6 Step l: as in Example 3.

Step 2: starting mixture-300 g. of a mixture of saturated CM-Cgz carboxylic acids (l0 parts). To the starting mixture are added 53 parts of saturated C18 carboxylic acid and 35 parts of saturated C20-C22 carboxylic acid, at 220 C. during 50 minutes, and 67 g. (3.7 mols) of water are condensed off.

The reaction product is soapy, is soluble up to 80 C. in a 1:1 proportion in Water forming a clear solution. If cooled further, a stable pasty emulsion results, which can be diluted with Water to form a cooling, lubricating or detergent substance.

Example 7 Reaction step 1: as in Example 3.

Reaction step 2: 280 g. (l mol) of puried oleic acid is added at 220 C. in a period of 25 minutes. 50 g. of Water (2.8 mols) are condensed off.

The reaction product, when solidifying, becomes a honey-like substance which, when diluted with distilled water in a proportion of 1:1, forms a concentrate for cooling, lubricating, and detergent use, and can be further diluted with water in any proportion.

Example 8 Reaction step l: as in Example 2.

Reaction step 2: similar to Example 2; however, instead of tall oil, 280 g. (l mol) of purified oleic acid is added during a period of 60 minutes at 200 C. and 94 g. (5.2 mols) of water are formed and removed.

The above product is a particularly useful concentrate for cooling, lubricating and cleaning use, when diluted 1:1 with water. Ten percent of a hydrocarbon fraction, as described in Example 2, may be added.

Example 9 630 g. (6 mols) diethanolamine are mixed with 180 g. (3 mols) boric acid, at approximately 100 C., and then 420 g. (approximately 1.5 mols) of tall oil, mixed fatty acids, are added.

The reaction between the diethanolamine and the boric acid starts at 130 C. While adding heat, the temperature is driven during a period of about 30 minutes, to 220 C.; 192 g. (10.6 mols) of water are condensed off. In another vessel, a hot mixture of 315 g. (3 mols) of diethanolamine and 300 g. (2 mols) of triethanolamine, at a temperature of 220 C., is added to the first reaction product. Reaction is continued for about 30 minutes, and 70 g. (3.9 mols) of water are split off.

The reaction product is dissolved in distilled water in a proportion of 1:1 and forms, either in its pure form or if mixed with a hydrocarbon fraction, according to Example 2, an excellent, lubricating and detergent concentrate.

As mentioned above, one embodiment of the invention involves preparation of reaction products, the complete composition of which is not known but which contain piperazine compounds. Careful control of reaction temperature and inclusion of a carboxylic acid in the reaction of aminoalcohol and boric acid makes this possible. This feature is illustrated below in Examples and 11.

Example 10 840 g. (8 mols) diethanolamine are mixed with 247 g. (4 mols) of boric acid, at approximately 100 C. 560 g. (approximately 2 mols) of tall oil are added. The resulting mixture is carefully heated to a temperature of about 135 C. Heating is then slowed, and controlled such that the mixture reaches a temperature of 150 C. in approximately 30 minutes. Thereafter, the mixture is heated substantially so that it reaches a temperature of 230 C. within a further period of about 60 minutes. 310 g. (17.3 mols) of water are condensed out.

The reaction product is soluble in water in a proportion of 1:1 and forms an excellent cooling, lubricating and detergent concentrate. Isolation of 1,4-di-beta-hydroxyethylpiperazine from the reaction product, by repeated recrystalizing from methoxy-hexanol (4-methoxy- 4-methyl-pentanol-2) can be done, to obtain it in its pure form.

Example 11 50 g. of the pure, undissolved reaction product of Example 10 are digested with 200 g. methoxyhexanol at 100 C. for 15 minutes and are decanted off while hot from the undissolved resinous residue. The hot solution is permitted to cool, and a sticky mass is separated out which cannot be filtered. After 24 hours, the remainder of the solution is poured off, and is reduced to about half volume in vacuum. Double the amount of benzene ether is added; after about 2 hours the layer forming on the bottom, and the solvent are decanted off, and the first, contaminated crystalline fraction is obtained. By recrystallizaton it can be purified. From the top layer, a very pure fraction is obtained. About 6 g. of the material, having a melting point of 130 C. are obtained. Analysis and infra-red spectrum determination conrm the identity of the product as 1,4-di-beta-hydroxyethylpiperazine.

Example 12 Using apparatus as described in Example 2: 840 grams (8 mols) diethanolamine are dissolved at about 100 C. in 244 grams (4 mols) boric acid, until a clear solution is obtained.

Thereafter, 240 grams (2 mols) ethyleneglycol monoethylether is added and the resulting reaction mixture is heated while being stirred well. This reaction starts at about 130 C. while water is being split off. The split-off water is collected in a descending measuring cooler vessel. After about 45 minutes to an hour, the reaction temperature is raised to S-210 C., until a total amount of 210- 216 ml. water is split off. Without interrupting the heating, 280 grams (1 mol) fatty acid, e.g. oleic acid, at a temperature of about 130 C. are added, for example through a tube; (it is observed that the temperature in the reaction vessel will fall to about 190 C.). As stated, heating is continued and the reaction with the fatty acid will start at about 195 C.; in a period of about 20 minutes, 54 ml. (3 mols) water are condensed off, and a iinal temperature of 220 C. is reached.

The product thus obtained is honey yellow, pours easily and may be used as a ready, Water soluble, clear, cooling and lubricating substance.

To provide a cutting fluid concentrate, fifty parts of the product obtained in accordance with Example 12 are mixed with parts water and 5 parts of hydrocarbon, as described above in connection with Example 2. The product has excellent rust-inhibiting characteristics and all the other characteristics heretofore described.

Example 13 Starting ingredients and steps are as above in Example 12 until the point at which, at 205 C., 216 m1. water are split off (same reaction conditions and quantities of diethanolamine, boric acid, and diethyleneglycol monoethylether) Then, one mol of hot triethanolamine is added and thereafter at least one mol water is condensed off. As above described, one mol (280 g.) of oleic acid is added and 3 mols (54 ml.) water are condensed out. Final temperature is approximately 200 C. The product obtained is thick and honey-like, and is an excellent emulsier.

Example for a cutting fluid concentrate: parts of the product in accordance with Example 13 are mixed with 20 parts of spindle oil and 30 parts of water. The resulting product is a clear, easily mobile liquid which easily dilutes clear in water to form working solutions and has excellent rust-inhibiting properties.

Example 14 Similar to Example 13, but instead of one mol of triethanolamine, one mol (6l g.) of monoethanolamine is added. All other conditions are the same, even the water being split off and the nal temperature.

The product is slightly opaque when dissolved in water, and can be used as such as a cutting fluid.

Example 15 A mixture of diethanolamine and boric acid, in the same quantities as in Example l2; thereafter, 360 grams (3 mols) of diethyleneglycol monoethylether is added. The mixture is heated to about 205 C., and 216 ml. water are distilled olf. Without interrupting the heating, as described, 280 grams of oleic acid (l mol) are added, heated in about 30 minutes to 220 C. and kept at that temperature for about 30 minutes. 4 mols of water (72 ml.) are distilled off.

The product without addition of hydrocarbons is liquid, clearly soluble and may be used directly in water as a concentrate; and further it is readily thinned with water in proportions of 1:30 to 1:50 to give a viscous clear working solution. The product has particularly good cutting fluid properties, that is, it is particularly good as a lubricant coolant and leaves a smooth cut.

Example 16 Quantities of diethanolamine and boric acid, as described in Example 12, are dissolved when hot. Thereafter, 268 grams (2 mols) of diethyleneglycol monoethylether are added and heated as above described. After 50 minutes a temperature of 200 C. is reached. 216 ml. water are distilled off. Then, as described, 560 gram (2 mols) of oleic acid are added and, in a period of 20 minutes, 4 mols water are condensed olf at a temperature of between C. and 210 C. The resulting product is liquid and is an excellent emulsiier.

To form a concentrate, 50 parts of the resulting product are mixed with 30 parts water and 20 parts hydrocarbon, as described in connection with Example 2. There is formed a clear, honey-yellow thin liquid which can be further diluted with water to form working solutions, remains clear, and has excellent rust-inhibiting properties.

9 Example 17 Proceeding exactly as in Example 16 above, but instead of diethyleneglycol monoethylether, 236 grams (2 mols) of diethyleneglycol monobutylether are used. A concentrate may be made as above described in connection with Example 16.

Example 18 1,260 grams (12 mols) of diethanolamine are mixed with 244 grams (4 mols) of boric acid, as described, an initial reaction temperature is 130 C.; thereafter, the resulting mixture is heated to a temperature of 240 C. and 216 ml. water are condensed off. The reaction mixture is left to cool and, when at 180 C., a mixture of 280 grams (1 mol) of oleic acid, and 320 grams (2 mols) of diethyleneglycol monobutylether, are added. The combined reaction mixture is heated again. The reaction starts at about 250 C. The reaction temperature is kept during a period of time of about 11/2 hours at 220 C. by regulating the heating. In this period, 125 g. water (7 mols) are condensed olf.

The product is liquid and clearly soluble in water, and in this form provides an excellent cooling and cutting uid concentrate.

Other glycols which, by experiment, have been tested for suitability are: ethyleneglycol mono isopropylether, ethyleneglycol mono butylether, ethyleneglycol mono ethylether, dieth-yleneglycol mono ethylether, trioxypropane, sorbtol.

The characteristics of the reaction products obtained according to the examples above will now be described, with reference to the accompanying drawings in which:

FIG. 1 is a family of titration curves in which the ordinate represents pH values and the abscissa 0.1 normal hydrochloric acid;

FIG. 2 is `an illustration of a testing apparatus to test broad area lubricating eiectiveness; and

FIGS. 3 and 4 are tables explaining experimental results.

The compositions of the present invention have substantial buffering action7 and may be referred to as broad spectrum buffers. They are distinguished from known mixtures of buffering agents in that they do not cause precipitates with calcium-containing water even in a one percent water solution. With a pH range between 9 and 7, they are still capable of capturing 21 milliliters of 0.1 normal hydrochloric acid, as shown by titration curve A1 of FIG. 1. A different product, the formula of which is indicated in FIG. 1 of the drawing with respect to curve C, having molecular proportions of 2:1 of triethanolamine and boric acid salts could capture only 13.5 milliliters of N/ 10 hydrochloric acid.

Referring again to the curves of FIG. 1, and particularly to titration curve B: a desired reaction product obtained in accordance with Formula II of the boric acid salt of the 1,4-di-beta-hydroxyethylpiperazine can capture twelve milliliters of 0.1 normal hydrochloric acid at the neutral point of pH 7, or 0.1 normal of sodium h-ydroxide, without any change in pH value. This is also seen by extreme position of the two titration curves A and B. Titration curves C, D and E illustrate the results achieved with different compounds, the composition of which is indicated on the right hand of FIG. 1.

In general it may be stated that the pH value of the solutions is below 9, which is particularly important to prevent skin irritation. The rust inhibiting effect of the broad spectrum buffering substances of the present invention is conjoined with the buffering eiect itself, which can be shown by experiments to be described.

The corrosion inhibiting effect of boric acid triethanolarnine salts, in a molecular proportion of 2:1, is compared with the reaction product obtained in Example 1, as well as with boric acid salts of the l,4-di-betahydroxy ethylpiperazine.

Test conditions: milling machine chips of cast iron,

for example of 3.47 percent carbon, 2.33 percent silicon, 0.77 percent manganese, 0.29 percent phosphorus and 0.116 percent sulphur are obtained by dry machining. The chips are approximately 5-7 mm. long and have a thickness of about 1 mm. A small heap of about 40 mm. (1.6 inches) diameter and about 8-10 mm. high is placed on a watch glass of about 1() cm. (4 inches) diameter.

A solution of the substance to be tested, in distilled water, is prepared and poured over the heap of the chips so that the chips are completely wetted. Thereafter, excess solution is poured olf by tilting the watch glass, so that only so much of the solution remains as is coated on the chips. -T his little heap of chips is left alone at a temperature of about 18 to 20 C. and in ordinary humidity of to 60 percent. The test for rusting is done by rst considering the aspect of the chips from the top, to determine if there has been any rust formation; if there is then Table I (FIG. 3) will indicate Yes; if not then No. If no rust is formed, a further inspection is done by observing the chips from below, through the watch glass and making the following determination:

No rust-No.

Below 5 spots-Minimal.

Below 25 spotsSmall.

About 25 spots-Yes.

Table I (FIG. 3) clearly shows that the corrosion inhibiting eifect of the products to be compared is parallel with the buifering effect described in connection with the curve of FIG. 1. Substance No. 3 (rst column Table I) is the reaction product obtained in Example I; this does not show any rust formation even in a dilution of 1 percent with a pI-I below 9. Rusting occurs even at the 4 percent solution of triethanolamine and boric acid, when the pH value of 9 is exceeded. Even the 1,4-di-beta-hydroxyethylpiperazine, although it has a lower pH value, has a better corrosion inhibiting eifect than triethanolamine, which is particularly apparent when the acid salts of the bases with boric acid are compared, that is the results of Substances Nos. 4 and 8 of Table I. The substances, which are compared, have an alkaline N-atom corresponding to one each acidic boron atom. In spite of the lower pH value, the use of l,4-dibetahydroxyethyl piperazine salts improves the rust inhibiting eifect (Substance No. 8).

The unusual character of a reaction product such as that obtained in Example I is indicated by titration curve A in FIG. 1. It is seen that the titration curve does not change, even when the solution has been yboiled for two hours. If the product would hydrolyze, then titration curve A would change to have the shape of titration curve B, which shows the behaviour of a watery solution, of equal percentage contents, of diethanolamine and boric acid (mol proportion 2: l). This, however, is not the case. The reaction product of Example I is saponified only by very strong acids, for example smoking hydrochloric acid. If the reaction conditions are properly arranged, boric acid can be obtained again practically quantitatively in cnystalline form. This method can be used in order to determine the boric acid content in the compound.

The substances of the present invention have desirable biological characteristics; they are bacteriostatic, and fungicidal, when in the concentration under which they would normally be used; but when diluted substantially with water, they become bacteria-degradable.

Tapping fluids, based on mineral oils, may cause dermatalogical irritations, for example causing oil-acne (LE. Dalton, J. American Medical Association, 1951, pages 147 et seq.; and W. Morris and C. M. Maloof, New England Medical Journal, 1952, pages 247 and 440). Besides the oil itself, additives often added to oil base cutting fluids cause additional irritation; such additives may be alkaline soaps, petroleum sulfonates, or other emulsiiers to make the mineral oil products water emulsiiiable or water soluble. Experiments have shown, that the reaction products of the examples given above, do not cause irritation to the human skin when diluted to the extent useful in the metal working industry. The experiments were made with persons working in the industry, and who already were sensitized to metal working cutting fluids. The following solutions were prepared:

(1) A l-percent solution according to Example 1;

(2) A l-percent solution according to Example 2;

(3) A 1-percent solution of pure 1,4-di-beta-hydroxyethylpiperazine made according to Examples l and ll.

Small patches were applied to the skin of the persons testing the material; the patches were permitted to remain for 24 hours. The test volunteers, before having the patches applied, were subject to the following dermatological diseases; dermatitis; eczema; mycotic eczema and infective eczema; sporyasis; lichen ruber and pityriasis rosea.

After 24 hours, no reaction was noted in any one of the patches; no irritation to the skin under the patches could be determined.

Bacteriostatic effects Cooling lfluids prepared on the basis of emulsied hydrocarbons are particularly subject to bacterial attack, which occur primarily in the form of anaerobic bacteria, which attack the sulfone groups of the emulsifiers. These sulfone groups are reduced and poisonous, foul smelling hydrogen sulfide is liberated. This also, of course, de composes the cooling oil. In order to prevent decomposition, air can be bubbled through the solution continuously, or buffering additives may be used. The use of additives, or air, is costly. In contrast, the reaction products of the present invention do not contain any sulfur, or sulfur compounds, and thus such anaerobic bacteria do not have any medium to grow on. Reaction products of the present invention have bacteriocidal, fungicidal and insect repellant (and to some extent insecticidal) properties; they are effective against gram-positive, as well as against gram-negative bacteria. They inhibit the growth of bacteria, as well as parasitic fungi, and are repellants for the carrier of these bacteria and fungi, mainly insects and particularly flies. The bacteriocidal, fungicidal and insecticidal properties are obtained without the addition of chemical compounds usually used for such purposes, such as halogens, phosphorus, or metal-containing compounds.

Experimental basis for tests for bacteriocidal effect A growing medium of blood agar is infected with bacteria, as listed below, by applying thereon small bits of filter paper, of about 9 mm. diameter. The growing medium was left for 24 hours at 30 C. The test solution was prepared according to Example 2.

Dilution of reaction Results Product according to Example 2 Staphylococcus Bacterium Prodgiosum (Gram-positive) (Gram-negative) Effective Inhibition..." Effective Inhibition. 17 do Do. 1/l0% Little Inhibition Little Inhibition.

TABLE II Percent dilution of Limit of Growth The dilution limit at which growth still occurs is less than with bacteria, namely at between 0.02 and 0.01 of the concentrate.

It has been found that concentrations of the reaction product down to 0.5% have insecticidal effect, and at even greater dilutions the reaction product still acts as an insect repellent. Thus, the carriers of disease and irritation, particularly flies, are not attracted -to equipment utilizing a cooling fluid according to the present invention. The data of Table II, and the experiments show that a reactive product of the present invention, without any additives :used in the insecticidal or fungicidal field, and without any poisons, inherently has bacteriocidal, fungicidal and insecticidal effects when used in the concentrations best suited for `metal working, for example, as a cutting fluid. When the substance is, however, diluted, as for example in a settling tank, or in a disposal system, that is when it is present in concentrations below 0.02%, and for example 0.001%, if not only loses all its bacteriocidal effects, but on the contrary becomes bacteriologically degradable. It thus can be disposed of without causing pollution of rivers, lakes, or waterways.

Metal-workin g utility For practical use as a cooling lubricating and detergent concentrate for use in the metal working industry, for example as a cutting fluid, as a fluid for use in lubrication for rolling or drawing of sheet, or wire, for lathe turning, drilling and boring, tapping, and grinding, a concentrate of reaction product is diluted with water. The separate machines are preferably supplied from a central storage system, as is well known in the art, in which the proper dilution for the use of the machinery can be maintained. It has been found that, as cutting fluids, for example for use in a lathe, the reaction products of the present invention made according to the above Examples 2 to l1, are best utilized in a concentration which is above 0.1% and preferably in a region of from 1 to 3% of the substance, with the remainder water. The high degree of dilution of the cencentrate permits efficient utilization of the cutting fluid.

yIn order to test the lubricating effectiveness, various lubrication tests have been devised. Since the reaction products of the present invention are particularly useful in lathe cutting and grinding, where the contact of the tool with the work piece is not ordinarily along a point but rather over a broader area, for example ideally a line, a test apparatus to test lubricating effectiveness under simulated conditions is described. Reference may also be had to Schmiertechnik No. 4, pages 184-191; 1956, article by Bartel et al.

Referring now to PIG. 2: a test bolt 6 is inserted into a holding ring 4. Test bolt 6 is supported within the holding ring 4 on a pair of flattened pins 5, which are held against rotation within the holding ring 4. The test bolt 6 is arranged to be rotated, Holding ring 4, with its pins 5, is suspended by means of a steel band 1 from a holder 10. The relative pressure of pins 5 against the test bolt 6 can be adjusted as indicated schematically by arrows 2, 20. Holding ring 4 is provided with a lever 8, which bears against a scale schematically indicated at 9.

The suspension by steel band 1 is such that the pins 5 are exactly parallel to the axis of test bolt 6. The test bolt is made a carbon steel C-15, with about 0.1 micron roughness; it may have a diameter of about an inch and a hardness of 63 Rockwell. The pins 5 are offset 45 from either side of a vertical center line; the pressure of the pins against the test bolt, that is the forces schematically indicated by arrows 2, 20, are about 4,500 kg./cm.2; the relative speed 0.2 meter/ per sec. (for a l-inch test bolt, this corresponds to a speed of about 150 r.p.m.).

At the beginning of the test, a pure line contact is obtained between the pins and the test bolt. The test is carried out for a period of about 3 hours. The sliding contacts between pins 5 and bolts 6 are flooded with lubricating-cooling substances. During the test, vibration is considered; the friction at the beginning (nA) and at the end (aE) is measured. The temperature at the test stand at the beginning (TA) and at the end (TE) of the test is determined. After the test, the track made by the pins 5 is inspected.

If the surface is smooth and does not show any groove, then the lubricating efectiveness is good. A decreasing sliding friction (,uE /LA) shows a good lubricating film. Comparison of the temperature at the beginning and at the end of the experiment indicates the cooling effectiveness. The temperature difference should -be small.

The data of Table III, FIG. 4, show the results of the test, and comparison with known cooling iluids. Table III, FIG. 4, shows decreasing sliding friction, which is further indicated by the small degree of wear and the good aspect of the track made by the pins 5. Mineral oil based cutting oils, activated by additives, are initially better lubricants; but the much higher degree of heating, due to the smaller thermal capacity and cooling effectiveness of oils also decreases lubricating eiciency. In actual machining operation, heating of tools causes dulling and increases the necessity for resharpening.

The commercial cutting uid of Table III (FIG. 4) item 2, is a water dispersable fluid in which the dilution of l to 40 is the limit of the recommended use; the lubricating eiectiveness at this dilution is already impaired.

The present invention thus provides reaction products which are Water-soluble, water-emulsiable and dispersable. They are corrosion inhibiting and useful as `a cutting fluid in a metal working eld, they combine the advantages of high lubricating eiectiveness and corrosion inhibition of the mineral oil base cutting fluids with the high cooling eiciency of the water base cutting uids. They do not have any of the disadvantages of either, however, namely, subject to decomposition or a necessity for poisonous additives. Additionally, the reaction products of the present invention provide cutting uids which are bacteriostatic, and yet biologically degradable so that they can be disposed of readily Without causing pollution. When used as detergents, the reaction products have excellent cleaning properties and are efficient emulsiers and buffering agents. The property of biologic degradability, thus providing for ease of disposal, likewise obtains when they are used as detergents.

I claim:

1. A boronand nitrogen-containing reaction product is formed by:

reacting at least two molar proportions of a secondary aliphatic aminoalcohol with one molar proportion of a boron-containing compound selected from the group consisting of boric acid, HBO2, H2B4Oq and B203, at a temperature from about C. to about 230 C., and removing Water of reaction as it forms, whereby a boronand nitrogen-containing reaction product is obtained.

2. Process for the production of a boronand nitrogen-containing reaction product comprising:

reacting at least two molar proportions of a secondary aliphatic aminoalcohol with one molar proportion of a boroncontaining compound selected from the group consisting of boric acid, H1302, H2B4O7, and B203, at a temperature from about 130 C. to about 230 C., and removing Water of reaction as it forms, whereby a boronand nitrogen-containing reaction product is obtained.

References Cited UNITED STATES PATENTS 2,441,063 5/1948 Gilmann 260-462 X 2,408,332 9/1946 Morgan 260-462 X CHARLES B. PARKER, Primary Examiner.

R. L. RAYMOND, Assistant Examiner.

U.S. C1. X.R.

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