DE909022C - Process for the production of inorganic, water-soluble chromates containing, soap-containing, emulsifiable mineral oils - Google Patents

Description

Process for the production of inorganic, water-soluble chromates containing, soap-containing, emulsifiable mineral oils, water-soluble mineral oils find in the form of their aqueous emulsions because of the resulting lubricating and cooling effect multiple uses in metalworking, e.g. B. when drilling, Milling, drawing, grinding etc. The water solubility of the oils is determined by incorporation a soap, such as B. of petroleum sulfonates, fatty acid soaps, resin soaps achieved. The aqueous emulsions are also required to be used in the Metalworking have good anti-corrosion properties. There is also on So-called anti-corrosion oils made on the basis of soap-containing mineral oils, their actual purpose in preventing corrosion in metals lies. To give these oils the desired corrosion protection properties, it has already been proposed that the oils or their aqueous emulsions be an inorganic Incorporate chromate. The incorporation of inorganic chromates in mineral oils is however, with difficulties because of the low solubility of the chromates in mineral oils tied together.

A method for incorporating a water-soluble one already has Chromates, especially sodium chromate, in the soapy base oil before it Emulsification in water has been suggested, but this method is pretty laborious; in addition, a concentrate of an oil-soluble petroleum sulfonate is used required in a mineral oil with a petroleum sulfonate content of 3o to 70%. An aqueous solution of the chromate is mixed with this concentrate and the Mixture emulsified by stirring. After emulsification has taken place, will carefully stir the mixture to drive the water out of the emulsion heated. The concentrate obtained in this way is then riding the Base oil diluted, whereby the chromate-containing, water-soluble oil is obtained.

It has now been found that inorganic, water-soluble chromates in can easily be incorporated into soap-containing, emulsifiable mineral oils by using small amounts of an aliphatic compound with q. to io, in particular 6 to 8 carbon atoms and two alcohol groups or one alcohol group and one Carbonyl group as a solubilizer. After this procedure it is possible in simpler Way to make real solutions of chromate in mineral oil. The procedure also has the advantage that you do not need to have a sulfose soap concentrate, because one can also use less concentrated solutions of petroleum sulfonates or others Use soaps in a mineral oil.

The invention therefore relates to a method of manufacture Soap-containing, emulsifiable ones containing inorganic, water-soluble chromates Mineral oils, which is characterized in that the mineral oils have a low Amount of aliphatic compounds with q. to 10, in particular 6 to 8 carbon atoms and two alcoholic hydroxyl groups or one alcoholic hydroxyl group and incorporated into a carbonyl group and a small amount of inorganic, water-soluble Adds chromates.

As examples of dihydric aliphatic alcohols, which have proven to be excellent as solubilizers, octanediols, such as 2-ethylhexanediol-i, 3 and hexanediols, such as hexanediol-i, 6 or 2-methylpentanediol-2, q., Are mentioned. As an aliphatic compound having a hydroxyl group and a carbonyl group; Which is suitable as a solubilizer, diacetone alcohol should be mentioned. The amount of Solubilizer can vary between fairly wide limits. In general is the solubilizer in amounts of i to io percent by weight, based on the Total mixture, used. It has been shown to be useful, the weight-based Quantity ratio between the chromates to be dissolved and the solubilizers to choose between the limits of i: i and i: io.

The inorganic, water-soluble chromates are potassium and sodium chromate Most appropriate. If desired, however, other inorganic, water-soluble ones can also be used Chromates such as ammonium chromate can be used. The amounts of weight used the chromates can fluctuate between fairly wide limits and are generally in the range between 0.1 and 10%, preferably between 0.5 and 2%, based on the total mixture. The chromates are advantageously in the form of a concentrated aqueous solution the mineral oils which already contain the solubilizer in whole or in part, admitted. For example, a solution of 1 part by weight of potassium chromate in 2 parts by weight is Water is very suitable for incorporation into the oils.

It has also been shown that the emulsifiable mineral oils, advantageously in combination with a water-soluble, inorganic chromate, also include water-soluble, inorganic nitrites, in particular an alkali metal nitrite. If desired, other nitrites, such as e.g. B. ammonium nitrite can be used. The combination of a chromate with a nitrite provides better protection against corrosion than a chromate or a nitrite on its own. Excellent results are achieved e.g. B. obtained by incorporating 0.5 to 1 percent by weight of potassium chromate in combination with 1 to 2 percent by weight of sodium nitrite.

The excellent effect of the combination of a chromate and one Nitrite shows up particularly clearly when you look at the preparation of the emulsifiable Mineral oil petroleum sulfonates used, which tend to the so-called black spots, d. H. Metals, which with aqueous emulsions from such petroleum sulfonates containing come into contact with emulsifiable mineral oils, color dark. It is also with Incorporation of a chromate, such as potassium chromate, in itself represents a certain degradation the black spots otherwise caused by certain petroleum sulfonates, but the occurrence of black spots is reduced to an even greater extent, when the emulsifiable mineral oils containing the petroleum sulfonates in addition to a nitrite such as sodium nitrite is added to the chromate, such as potassium chromate. For the sake of completeness, it should be noted that it can also be used without using a chromate or a combination of a chromate with a nitrite is possible to suppress the black spots by using the emulsifiable mineral oils in addition to the petroleum sulphonates which cause black spots, there is also a considerable one Amount of tall oil soaps incorporated; but it may be beneficial To be able to do without the use of tall oil soaps. This is achieved according to the invention by the fact that the emulsifiable mineral oils, which have a tendency to black spots Contain petroleum sulfonates, an inorganic, water-soluble chromate appropriate incorporated in combination with an inorganic, water-soluble nitrite. Be it but pointed out that the - invention in no way applies to the production of emulsifiable mineral oils, which are petroleum sulfonates with a tendency to black spots included, is limited. It is also important for other emulsifiable mineral oils to that a means is given by the method according to the invention, inorganic, to incorporate water-soluble chromates into the mineral oils in a simple manner. The inventive Process for incorporating a chromate, optionally in combination with one Nitrite, can therefore be used for any emulsifiable mineral oils.

The base oil from which the emulsifiable mineral oils are made Any mineral oil that can be used for emulsifiable mineral oils can be used be. It is advisable to use a light, refined mineral oil as the base oil, z. B. spindle oil.

The soaps dissolved in the base oil to bring about emulsifiability can be of various kinds be. Generally all come for them Preparation of emulsifiable mineral oils useful soaps into consideration. Examples such soaps are the oil-soluble petroleum sulfonates, tall oil soaps, fatty acid soaps, Naphthenic acid soaps, resin soaps.

The petroleum sulfonates which are suitable as soap can be used as by-products in the refining of mineral oils, e.g. B. spindle oil, with sulfuric acid or oleum can be obtained. To obtain the petroleum sulfonates one can proceed in such a way that one acid oil containing free sulphonic acids obtained during the acidification of the mineral oil neutralized with alcoholic lye and the aqueous alcoholic solution, which then contains sulfose soap Separate the solution from the deacidified neutral oil. By driving off the alcohol and one Part of the water from the solution containing sulfose soap is obtained as the thickened one Raw potash sludge. This sludge can then be cleaned in concentrated, z. B. about 85% alcohol are absorbed, with part of the sludge undissolved remains and is separated. The solution is made by distilling off the alcohol the purified petroleum sulfonate obtained, which is used to produce the desired water-soluble Oil can be dissolved in the mineral oil.

On the basis of the aforementioned raw potassium soap sludge, however, one can the desired emulsifiable mineral oil can also be obtained by using the raw sulfose soap sludge without further cleaning with mineral oil, e.g. B. spindle oil, mixed and this mixture with a mineral acid, e.g. B. sulfuric acid, treated with the petroleum sulfonates be converted into the free sulfonic acids. Two layers are formed here, which are separated. After the separated oil layer has been neutralized, it forms a suitable emulsifiable mineral oil.

The desired emulsifiability of the mineral oils can also be achieved by a Combination of two or more soaps of different types. For example, you can combine a petroleum sulfonate with a tall oil soap. The co-use A tall oil soap is beneficial if the petroleum sulfonate causes the black speckle tends and the chromate on its own, d. H. without using a nitrite, for Use. Another advantageous combination is the combination of one Petroleum sulfonates with resin soap and oleate.

The amounts of soaps incorporated in the mineral oils can be within limits fluctuate fairly wide. It is advisable to use amounts of soap from 5 to q.o percent by weight, based on the total mixture.

In some cases it has proven to be useful to use the emulsifiable To adjust mineral oil slightly acidic. The weakly acidic setting can, for. B. thereby caused that one of the mineral oils containing the neutral soap adding a small amount of tall oil. The acidic setting can also be used instead of tall oil any other weak acid or acidic salt, z. B. resin acids are also very suitable. It turned out that Aqueous emulsions made from slightly acidic mineral oils provide better protection against corrosion result as aqueous emulsions from the corresponding mineral oils, which however are adjusted to be weakly alkaline instead of weakly acidic. Also tend to be aqueous Emulsions made from the slightly acidic mineral oils are much less likely to foam than the emulsions obtained from the slightly alkaline mineral oils.

When tall oil is either for the acidic setting or in the form of a If soap is used as an emulsifier, it is advisable to distill the tall oil beforehand. It has also proven to be advantageous to make the tall oil distillate by heating to drive off about 3 to 5 percent by weight of the distillate in a vacuum with steam, which removes most of the unpleasant odorous substances.

In the manner indicated, it is not only possible to use the chromate, if appropriate in combination with a nitrite, in a simple way oil-soluble mineral oils Incorporate yourself, so the extra work of adding these ingredients to the emulsions is avoided by consumers, but according to the invention The mineral oils obtained have particular advantages that were not foreseen could become.

Through the combined use of a chromate and, if necessary a nitrite with a solubilizer of the type mentioned is namely in emulsification of the oil results in a reduction in the size of the oil particles and thus an increase the emulsion stability achieved. This effect is of particular importance for the production of transparently soluble mineral oils, which z. B. as grinding oil Find application.

The use of the solubilizer of the type described also has nor the special advantage that they are otherwise caused by soaps, such as petroleum sulfonates, caused strong increase in the viscosity of the mineral oil, thereby reducing the use of mineral oils is facilitated. This reduction in the The increase in viscosity caused by soaps is reinforced by the addition of chromate, such as potassium chromate, optionally together with a nitrite, such as sodium nitrite, in combination with the mentioned solubilizers. One can use the viscosity-lowering The effect of the solubilizer also advantageously evaluate in such a way that one the solubilizer, divided into different stages of the manufacturing process of the water-soluble mineral oils.

To increase the emulsifying properties of the mineral oils described you can still small amounts, z. B. Add o, z to 5%, of a stabilizer. Numerous substances are suitable as stabilizers, e.g. B. alcohols such as ethanol and Glycol, esters of higher alcohols, higher ethers, organic bases and organic salts Bases. Further examples of suitable stabilizers are the monomethyl ether des Ethylene glycol, the monoethyl ether of diethylene glycol, triethanolamine, triethanolamine oleate and diisopropylnaphthalene sodium sulfonate.

If desired, the mineral oils can also be foamed preventive means, like for example 13. Add ozokerite or montan wax. Slack wax obtained by dewaxing cylinder oil fractions is also very effective as an anti-foaming agent.

Leave the mineral oils obtained by the process according to the invention emulsify excellently with water, d. H. they go to practically ioo ° / a in Emulsion. Even very dilute emulsions (e.g. 0.5 to 2% oil-in-water) show practically no creaming even after standing for days. The emulsions, e.g. B. those derived from spindle oils containing alkali or ammonium petroleum sulfonates have been obtained are eminently suitable for metalworking, e.g. B. Drilling, milling, drawing, etc., mainly because they are very strong Ensure corrosion protection. Show even when used in 100% concentration Machined workpieces from the very corrosion-sensitive malleable cast iron, even for days Do not store any signs of rust. Generally used for metalworking Emulsions which contain i to io percent by weight, in particular i to 5 percent by weight, contain emulsifiable mineral oils.

Due to their good corrosion protection properties, the The mineral oils described are also excellent as anti-corrosion oils in water systems, For example, car coolers, press water circulations, etc., with additions of the described Mineral oils are suitable for water in quantities of 0.5 to 5%. Even if these water systems are heated to boiling temperature, the emulsions still remain flawless stable.

The invention is illustrated by the following examples. example i Made by treating a naphthenic spindle oil with 15 percent by weight Sour oil obtained oleum were after removal of the sour tar formed in this way and blowing out the sulfur dioxide formed with air, the oil-soluble sulfonic acids extracted with alcoholic-aqueous sodium hydroxide solution. As alcoholic-aqueous sodium hydroxide solution a solution of 6 parts by weight of sodium hydroxide in 100 parts by weight of 50% Ethanol used. From the extract solution thus obtained, the alcohol and a Part of the water distilled off, and it remained a soda crude sulfose soap sludge.

45 parts by weight of this raw sulfose soap sludge, which is 37 percent by weight Contains water and 45 percent by weight petroleum sulphonates, calculated as pure sulphonates, were at 40 ° with 55 parts by weight of a paraffinic spindle oil with a Viscosity Ego = 2.4 and a density d2o - o.885 mixed. To this in one The mixture contained in the leaded agiteur was passed through with vigorous stirring of air, 12 parts by weight of 96% sulfuric acid are slowly added, the temperature rose to 60 °. After one hour of mixing and eight hours of sitting, it was the lower aqueous layer, which contained sulfuric acid and sodium bisulfate in solution, deducted. To the supernatant acid oil were now by means of vigorous stirring Passing air through, 8 parts by weight of 96% sulfuric acid were added. After mixing and settling, the aqueous layer formed was again drawn off. After complete Peeling off the aqueous layer and the small amount of a dark gray sludge at the boundary of the layer the clear sour oil was blown with air until all sulphurous acid was driven out. The neutralization number (milligrams of KOH consumption per gram of substance) of the sour oil was 32.

The sour oil was neutralized with vigorous mixing at 50 ° in the manner that first two thirds of the neutralization number with 50% potassium hydroxide solution and then the remainder was saturated with 45% sodium hydroxide solution in such a way that it was neutralized Oil had an alkaline neutralization number of 0.5. Immediately after adding the last amount of caustic was 3 percent by weight, based on the neutralized oil, 2-Ethylhexanediol-i, 3 and o, i weight percent ozokerite added.

Then 0.5 percent by weight of potassium chromate was added to the oil, which was contained in the twice the amount by weight of water had been dissolved.

After mixing briefly, the oil was then 1.3 percent by weight a clear mixture of 75 parts by weight of tall oil distillate and 25 parts by weight of the above-mentioned spindle oil is set acidic. The neutralization number of the oil was 0.8 acidic after adding the tall oil / spindle oil mixture.

Finally, 2 percent by weight sodium nitrite, which was found in twice the amount by weight of water had been dissolved, was added.

The obtained mineral oil was easily emulsifiable in water, and the Emulsion had good resistance to hard water. The emulsion was very useful as Drilling oil and was characterized above all by good corrosion protection during processing by casting.

Emulsifiable mineral oils with equally good properties could also when using 2-methylpentanediol-2,4 instead of the aforementioned 2-ethylhexanediol-i, 3 can be obtained. Example 2 To illustrate the fact that the use of the Combination of an inorganic, water-soluble chromate with an inorganic, Water-soluble nitrite is particularly beneficial for lowering otherwise through Certain petroleum sulfonates caused black spotting were some comparative tests executed. In doing so, the properties were brought about with reference to those on metals Corrosion of some samples of emulsifiable mineral oils in the table below The specified composition was tested using the so-called Herbert corrosion test. (The Herbert corrosion test is described in the Journal of the Institute of Petroleum, Volume 36 [195o], pp. 152 to i54.) This test was carried out in the following manner, which something deviates from the original Herbert rule. on the Herbert plates were exactly four piles of about 2 g of steel filings applied in a flat layer. The four piles of chips were with every 2 cc of a 5% aqueous emulsion of the emulsifiable emulsifiable under test Soaked in mineral oil. The plates were then placed in a desiccator with the following dimensions brought: height 65 cm, diameter 36 cm, volume 641.

In the lower part of the desiccator there were 2143% sulfuric acid. For the sake of completeness, it should be noted that according to the original Herbert rule a saturated sodium bisulfate solution, which is mixed with undissolved sodium bisulfate in Touch stands instead of sulfuric acid.

The plates were 20 cm above the surface of the sulfuric acid.

A small fan was located 20 cm above the plates, which circulated the air inside the desiccator and thus ensured a relatively quick equalization of the humidity. The air humidity was measured by means of a hygrometer installed in the desiccator at the height of the fan. The air humidity was 50% before the plate was installed, rose to 65 to 70 % when two plates were installed and at the end of the test, which was carried out over a period of 24 hours, had again approximately returned to the initial value.

The evaluation of the corrosion or black spots caused on the plates happened with the notes i (no rust, no black spots, i.e. practically bare Plates) up to 5 (very strong rust or very strong black spots). The subdivision for the evaluation of results lying between the two mentioned extreme cases happened after half notes. The grade 3 roughly indicates the limit of usability.

The table below shows the results obtained in this way for some emulsifiable oils of the composition also given in the table. It should be noted that all oils were made slightly acidic with tall oil. The neutralization number of the oils before their emulsification in water is mentioned in the fourth column of the table. Tabel Emulsifier content content in weight in the finished percent of the emulsifying- neutral- manufacturing Herbert- Testable oil sation- emulsifiable test No. petroleum tall oil number of oil on note sulfo soap sour nat in in Na- potassium- Wt. Wt. Trium chromate Proc. Proc. Nitrite i 20 - o, 8 2 - 4 2 20 - o, 9 -. o, 5 2 to 3 3 20 - o, 6 ii 2 4 20 - 0.5 2 0.5 1 to 2 5 io io o, 8 2 - 2 As can be seen from the table, with those emulsifiable oils which only contain petroleum sulfonates as emulsifier, better corrosion properties are obtained through the use of potassium chromate than through the use of sodium nitrite. Excellent properties are obtained with the simultaneous use of potassium chromate and sodium nitrite. If 0.5% potassium chromate and 2% sodium nitrite are incorporated into the finished emulsifiable oil, which contains only petroleum sulfonate as an emulsifier, the corrosion properties measured according to the Herbert test are even better than for the oil, which is a mixture of the same Parts of petroleum sulfonate and tall oil soap as an emulsifier, but only contains sodium nitrite as an inorganic salt.

The base oil for all of the samples in the table above consisted of one Spindle oil with a viscosity E2 "° = 2.4. The incorporation of the inorganic salts (Potassium chromate and / or sodium nitrite) was done using 3 percent by weight 2 Ethylhexanediol-i, 3, based on the total amount of the finished emulsifiable oil.

Claims (7)

PATENT CLAIMS: i. Process for the production of inorganic, water-soluble chromates containing, soap-containing, emulsifiable mineral oils, characterized in that a small amount of aliphatic compounds with 4 to 10, in particular 6 to 8 carbon atoms and two alcoholic hydroxyl groups or with one alcoholic hydroxyl group and one carbonyl group are incorporated into the mineral oils and adding a small amount of inorganic, water-soluble chromates, especially potassium or sodium chromate. 2. The method according to claim i, characterized in that that as an aliphatic compound with two alcoholic hydroxyl groups 2-methylpentanediol-2, 4 or 2-ethylhexanediol-i, 3 is used. 3. The method according to claim i, characterized characterized in that as an aliphatic compound having an alcoholic hydroxyl group and a carbonyl group, diacetone alcohol is used. 4. The method according to claim i to 3, characterized in that the weight ratio between the chromates and the aliphatic compounds are chosen between i: i and i: io will. 5. The method according to claim i to 4, characterized in that the aliphatic Compounds in an amount of 1 to 10 percent by weight, based on the total mixture, be used. 6. The method according to claim i to 5, characterized in that the chromates are used in an amount of o, i to zo, in particular 0.5 to 2 percent by weight, based on the total mixture. 7. The method according to claim i to 6, characterized in that the chromates are in the form of a concentrated aqueous Solution can be added to the mineral oils. B. The method of claim = to 7, characterized in that the mineral oils also have a small amount water-soluble, inorganic nitrites, in particular an alkali metal nitrite, added. G. Method according to claim 8, characterized in that the nitrites in the form concentrated aqueous solutions are added to the mineral oils. ok procedure according to claims i to g, characterized in that the mineral oils used are petroleum sulfonates and / or other soaps, such as tall oil soaps, fatty acid soaps, naphthenic acid soaps and resin soaps. ii. Method according to claims i to io, characterized in that that the mixture is adjusted slightly acidic, expediently by means of a small Amount of weak acids or acidic salts.