DE2320856B2 - Solutions of iron carbonyls in gasoline hydrocarbons stabilized with organoaluminum compounds - Google Patents

Description

R ₁ -C-CH-R ₃ OR ₂

contain, where Ri is a hydrogen atom or a An alkyl group with up to 8 carbon atoms or an aryl or aralkyl group with up to 10 Carbon atoms or an alkoxy group with up to 8 carbon atoms or an aryloxy or Aralkoxy group with up to 10 carbon atoms or a group of the formula

-CH-CR ₅

i I!

R ₄ O

denotes, where the radicals R & R% R * and R ₅ independently of one another represent hydrogen atoms, alkyl groups with up to 8 carbon atoms or aryl or aralky groups with up to 10 carbon atoms, the organoaluminum compounds mentioned being contained in an amount that corresponds to one Part by weight of aluminum corresponds to 50 to 200 parts by weight of iron of the iron carbonyls contained.

2. Stabilized iron carbonyl solutions according to claim 1, characterized in that they additionally contain a hydrocarbon-soluble manganese or cobalt salt in an amount that is a maximum of about 0.04 g of metal per liter of ready-to-use dilute iron carbonyl gasoline hydrocarbon solution

The invention relates to stabilized solutions of iron carbonyls in gasoline hydrocarbons.

The technical application of metal carbonyls has in the last 3 decades in gained considerable importance in various fields of chemistry. Are under metal carbonyls as is known, compounds of Metalla'omen and carbonyl groups understood in which the carbon atoms partly by covalent bonds and partly are coordinated with the metal atom. Some known metal carbonyls form complex cyclic ones Systems which also contain some different metals are difficult to handle and often difficult to achieve interpretive binding relationships exist.

The oldest known metal carbonyls include, in particular, the carbonyls of metals from the VIII. Group of the periodic table, such as nickel tetracarbonyl. Iron pentacarbonyl and cobalt tetracarbonyl. These three metal carbonyls have a considerable amount metallurgical importance as it given their low boiling points are fractionally distilled which enables the production of chemically pure metals. Nickel tetracarbonyl and iron pentacarbonyl are also used, for example, as catalysts by technical ■> Meaning, as they have certain key syntheses, such as the oxo synthesis and the Reppe synthesis, make possible.

In the field of engine technology, too, these were Metal carbonyls are used sporadically, since they, for

ίο Fuel added, increase the octane number significantly. In However, this connection shows a serious deficiency of these compounds, namely theirs Instability, which is why so far none fuels containing metal carbonyl are produced

is that could have been shown to be storable. So starts z. B. an originally clear dilution of iron pentacarbonyl in motor gasoline hydrocarbons with a degree of dilution corresponding to 0.5 g Iron per liter already after 2 hours as a result of a Excretion of iron pentacarbonyl breakdown products that are insoluble in motor gasoline gradually settle as a thick reddish-brown sediment. This process continues until the remaining motor gasoline does not contain any iron in the form of Pentacarbonyl contains more and its octane rating the same value as before the addition of the pentacarbonyl has decreased. This degradation process is accelerated by light, which makes the case even more difficult This behavior is in contrast to the Eigen shafts of motor gasoline, in which lead tetraethyl or Tetramethyl lead can be used as a means of increasing the octane number.

The aim of the invention is now to make available Solutions of iron carbonyls in petrol hydrocarbons substances in which the iron carbonyls are no longer in Decomposition products are converted, which are insoluble in gasoline hydrocarbons and as a result form disturbing suspensions with deposits of a sludge-like sediment. Of course, introduces Such a degradation process not only means that such solutions for purely mechanical reasons or from Reasons of consistency are no longer usable for the intended technical purpose, but the decomposition naturally also has the consequence that the Iron carbonyl content of the solutions - which is the prerequisite for their technical usefulness for certain Purposes forms - rapidly becomes lower and lower, so that the solutions in this way are their desired ones lose technical properties.

The solution to the problem mentioned is with Organoaluminum compounds stabilized solutions of iron carbonyls in gasoline hydrocarbons proposed that the stabilizing organoaluminum compounds are reaction products of aluminum

«Trialkoxides with one or more carbonyl compounds of the general formula

R ₁ -C-CH-R,

Il I

O Rj

contain, wherein Ri is a hydrogen atom or a An alkyl group with up to 8 carbon atoms or an aryl or aralkyl group with up to 10 carbon atoms or an alkoxy group with up to 8 Carbon atoms or an aryloxy or aralkoxy group of up to 10 carbon atoms or one

Group of the formula —CH — C-Rs R ₄ O

means, where the radicals R2, R3, R4 and Rs independently from each other for hydrogen atoms, alkyl groups with up to 8 carbon atoms or aryl or aralkyl groups with up to 10 carbon atoms, where the said organoaluminum compounds in one Amount contained are one part by weight of aluminum to 50 to 200 parts by weight of iron Corresponds to iron carbonyls

According to a further embodiment of the invention, the iron carbonyl solutions stabilized as above can contain, in addition to the organoaluminum compound mentioned, a hydrocarbon-soluble manganese or cobalt salt in an amount which is at most corresponds to about 0.04 g of metal per liter of ready-to-use, dilute iron carbonate / gasoline hydrocarbon solution

Active organoaluminum compounds which can be used according to the invention can in the simplest manner Case by implementing z. B. acetone can be obtained with aluminum triethoxide; however, are preferred Aluminum tripropoxide or aluminum butoxide used Instead of acetone, methyl ethyl ketone or high molecular weight ketones can also be used will. Diketones are also useful and especially advantageous when their carbonyl groups are in the "," - position stand to each other (i.e. separated by a CHr group), since in this Fr'.l they have a so-called have acidic methylene groups, d. H. a group with two easily mobile or exchangeable hydrogen atoms, the simplest being acetylacetone The ketones can be of a mixed aliphatic-aromatic character, so that acetophenone, for example, can be used with advantage. Among the aldehydes are formaldehyde and acetone

aldenyd is less suitable, but its usefulness increases with longer chain length, e.g. with propionaldehyde or especially butyraldehyde or isobutyraldehyde. Bring even greater chain lengths no advantages. Also in the case of aldehydes is closed mention that they are of aromatic or blended aromatic-aliphatic character can be what means that benzaldehyde or phenylacetaldehyde are useful.

Insofar as the structure of the .inventive organic

aluminum compounds esters are used, the formic acid esters prove to be less Advantageously, on the other hand, esters of acetic acid, propionic acid or butyric acid can be used with advantage will. However, high molecular weight esters do not result

special advantages. Ethyl acetate or methyl acetate are preferred.Also aromatic esters, such as phenylethyl formate or acetate or ethyl cinnamate can be reacted with the aluminum alkoxides.

In the reaction to be carried out to build up the stabilizing organoaluminum compounds according to the invention, the ratio between the alkoxide and the compounds to be reacted with it not to be stoichiometric. That means

jo z. B. for a simple case, i.e. H. the implementation of Aluminum tributoxii with acetone, in which 1 mol of tributoxide reacts stoichiometrically with 1 mol of acetone wherein the metal forms an enolic bond with the tautomeric form of acetone to form

Γ) of 1 mole of butanol according to the equation

AI (OQH.,)., + CHj-CHj-CH-C = _C-2 CHj + C ₄ H ₉ OH

.O

I OAH OC ₄ H,),

Connection B A

that it is more advantageous to use a ratio of less than 1: 1 instead, since compound A according to the above formula for the production of the stabilizers, taking into account the temperature and pressure conditions and mainly the fact that the reaction products are in contact with a optimally large metal surface are present, reacts with itself to form complex reaction products, the structure of which to a large extent is unknown. "Real" organometallic compounds with metal-carbon bonds are also present within these products. These secondary processes run with additional regression of the original butanol, which is then available for the implementation of additional amounts of aluminum.

The reaction is carried out at temperatures between 80 and 300 ⁰ C, warpage & we ^ e between 120 and 200 ⁰ C, carried out at normal or elevated pressure and in the presence of aluminum metal in such an amount and in such a degree distribution in the reaction vessel, so that an optimally large contact area between metal and liquid reaction compound can be maintained during the course of the reaction. With regard to the technically advantageous 4 ") first embodiment, this means that the metal in the Reaction vessel in the form of a loose layer of metal particles, the particle size (diameter) of which should lie between approximately 0.5 and 5 mm, preferably between 0.5 and 2 mm, i.e. H. in the form of grains

"> o is present. An even smaller particle size makes it difficult to obtain the strongly exothermic Control process. An optimal contact area between metal and liquid reaction mass is preferably through a layer of solid metal

V) ensures that the highest liquid level of the Reaction compound or mass reached in the course of the process. These conditions in the reaction vessel require that with the reaction compound or metal in reaction contact

ho surface area does not suffer any significant reduction during the reaction process (viewed as a percentage). In most cases a colloidal metal suspension is formed, which together with a rising Porosity of the surface of the metal particles not only

ii "> the surface cluster due to the relatively small The proportion of metal that disappears during the reaction is compensated for, but also an increase in the entire activated metal surface.

Stabilization systems prepared according to the above description are used in iron carbonyl solutions in Petrol brought in. It is advisable to use petrol in the first step of mixing Concentrations chosen that the iron carbonyl - for reasons of reaction kinetics - in one not too diluted state is combined with the aluminum compounds of the stabilization system.

For example, it has proven to be expedient to prepare standard stock solutions in which the iron carbonyl is present in an amount of 20 percent by volume is present and the amount of organically bound aluminum metal is about 5 to 30 g of metal per liter This does not in principle mean any restriction on the concentration conditions of the stock solutions. Because such Standard stock solutions can be stored for practically an unlimited period of time without the carbonyls Showing any signs of deterioration, they can be used as a beneficial way to store the Metal carbonyls are considered with regard to a later metering.

For ready-to-use motor gasoline with an increased octane number due to the addition of iron carbonyl, it was found that that a suitable stabilizing amount in the stabilizing system according to the invention an amount from about 1 part by weight of aluminum to 50 to 100 parts by weight of iron of the added iron carbonyl Corresponds to Higher additives are also effective, but less economically useful. Minor additives also have a stabilizing effect, but it is clear that this effect is reduced with decreasing content until it is no longer sufficient

However, it can happen that an aluminum stabilization system according to the invention does not give a sufficiently long stabilization, especially if the z. B. up to an iron carbonyl content of 0.2 to 0.6 g per liter of motor gasoline solution in addition dilute solutions of iron carbonyl in gasoline hydrocarbons, e.g. B. in tanks, barrels, etc. with Iron surfaces are in contact. You can then use small amounts of petrol-soluble organic salts of manganese or preferably cobalt in these diluted ready-to-use iron carbonyl solutions bring in, the amount of these metals per liter of diluted finished motor petrol not exceeding 0.04 g Metal should go out. Acids suitable for the synthesis of these metal salts can be aromatic as well as aliphatic or naphthenic Be acids. The use of salts of 2-ethylhexanecarboxylic acid has proven to be particularly advantageous proven.

Although it is already earlier than an iron pentacarbonyl Motor gasoline containing anti-knock agents with an addition of aluminum isopropoxide and this Mixture has been tested in a single-cylinder gasoline engine (US-PS 25 46 421). With this only to For comparison purposes, it was found that such a mixture had a 3.36ma! causes more abrasion on the piston rings in the cylinder than a gasoline containing iron pentacarbonyl alone. The one created by this result Prejudice has led away from the development of the present invention.

Other proposals, in motor fuels containing iron pentacarbonyl, decompose iron pentacarbonyl by adding certain metal-free ones Stabilizers, such as neutral alkyl ester alkyl amides of saturated aliphatic hydroxypolycarboxylic acids (U.S. Patent 2,493,714) or phosphatides ^, e.g. Lecithin or cephalin (US-PS 23 65 377) to prevent and thereby improve their shelf life sern, have brought no practically significant successes; those stabilized with such additives Iron pentacarbonyl hydrocarbon solutions remained clear at most from 1/2 to a maximum of 26 days and then inevitably occurred the - indicating decomposition -

to cloudiness on.

In contrast, the solutions of iron carbonyls stabilized with the organoaluminum compounds defined according to the invention in gasoline hydrocarbons have such a high level of stability and storage resistance to that even after storage of no sign of instability or instability for up to 2 years

Decomposition - recognizable by any deposits

- occurred

So was z. B. a unleaded gasoline, starting octane

number about 92, with a StammIö ^c Mng, which had been prepared from 20% by volume of iron pentacarbonyl and 80% by volume of a stabilizer prepared according to the above Example 1 using acetone and ethyl acetate, added in such an amount that the gasoline 0, 4 g Iron per liter of gasoline, corresponding to 4.8 ml of stock solution per liter. After a storage several samples of the gasoline stabilized in this way at room temperature did not show any after 100 days Excretions or any other chemical

Changes in the gasoline samples were detected and

even after storage for 2 years there was none

Excretion and only a slight darkening

watch.

The invention is illustrated by the following examples

explained in more detail

Example i To make an aluminum stabilizer was

A 4 liter flask equipped with a reflux condenser with gas outlet and a calibrated addition funnel was used. The flask was loaded with 2 kg Aluminum metal in the form of pellets with a diameter of about 3 to 8 mm and with 100 ml of n-butanol charged and heated to about 8O ^{0 C.} At this temperature the reaction between metal and alcohol started. The aluminum metal can be activated beforehand with iodine. The heat supply was continued until the temperature reached about 120 ⁰ C. Thereafter the supply of heat was interrupted and preferably with a continuous addition of n-butanol started at a rate of 100 ml / 10 min. This alcohol addition was continued until the total amount of alcohol was 2 liters. During this Addition time, the temperature of the reaction mixture rose continuously and finally reached about 135 to 145 ° C.

Provided that the alcohol intake was controlled at the above rate, he one kept a reaction system in which the reaction product was not dissolved in an excess of n-butanol, but was in the form of a melt. In a certain amount of aluminum was colloidally suspended in this melt, and therefore the surface of the

h ") Aluminum metal very large. Two liters of n-butanol converted about 196 g of aluminum into an aluminum tributoxide melt, in which more Aluminum metal was colloidally suspended.

A mixture of 500 ml of acetone and 500 ml of ethyl acetate was continuously fed into this melt at about 135 to 145 ° C. for 45 minutes. The reaction now taking place was exothermic, so that there was no rapid decrease in temperature. The final temperature of the reaction mass should not be lower than 110 ⁰ C. The liquid reaction mass was drawn off or allowed to run off and diluted with a mixture of hydrocarbons, the boiling range of which corresponded to that of ordinary car gasoline, in such a way that a total volume of the reaction mass of 4 liters was obtained.

The solution obtained is referred to here as an "aluminum stabilizer". With this aluminum stabilizer became a standard solution of iron pentacarbonyl by mixing 30 ml of stabilizer, 50 ml conventional unleaded car gasoline and 20 ml of iron pentacarbonyl, making 100 ml of stan-

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UQI UIUSUIIg nut i \ jl \ 3 aiauiuaici ifclit ι_.ιοι.ΐιμι ~ ιιιαν.αι wiijt

were obtained.

This standard solution, designated Type A, had the following quantitative composition:

Iron per 100 ml
Aluminum per 100 ml
Ratio Fe: Al

8311g
0.150 g
55.4: 1.

This type A standard solution could be obtained without any separation of solid ferrous Decomposition products are stored that would otherwise occur after a few hours with a standard solution with the same iron pentacarbonyl content - but without the addition of organically bound aluminum - occurs and causes a rapid decrease in the iron content in the solution.

By diluting 6.0 ml of type A standard solution with 1 liter of conventional unleaded car gasoline Octane number 89.1, corresponding to an iron content of 0.5 g per liter, was a car gasoline with a Obtained octane number of 983. This diluted motor gasoline solution could do without any deposits of decomposition products of iron carbonyl, which of course cause a very rapid decrease in octane number would have caused to be stored.

Type B: A standard iron pentacarbonyl solution with a content of 20% was made by reacting (mixing) 10 ml of the aluminum stabilizer this example with a solution of 20 ml of iron pentacarbonyl in 70 ml of conventional unleaded car gasoline prepared to obtain 100 ml of stabilized iron carbonyl solution having the following properties became:

Iron content per 100 ml 8311 g

Aluminum content per 100 ml 0.050 g
Ratio Fe: Al 166.22: 1.

This stabilized 20% iron pentacarbonyl standard solution had the same shelf life as variant A.

When 6.0 ml of this standard solution is diluted with 990 ml of unleaded conventional car gasoline and 10 ml of a 2 g metallic cobalt per liter in the form of the cobalt salt solution containing 2-ethylhexanecarboxylate were added in the motor gasoline, a motor gasoline was obtained with the following metal contents:

iron

aluminum

cobalt

Op g / l
0.003 g / l
0.020 g / l.

This gasoline mixture could be used without any cleavage

formation of decomposition products of iron carbonyl!

be stored, and also the addition of iron ore Copper shavings did not cause any decomposition de;

■> added iron carbonyl.

Example 2

In the same apparatus as in Example I, di < half the amount of n-butanol, d. H. 1 liter, with the same

ίο amount of aluminum and under the same temperature Conditions implemented as in Example I with the formation of half the amount of aluminum tributoxide. This conn The mixture was then mixed with a mixture of 500 ml of acetor and 500 ml of ethyl acetate at the same temperature conditions brought to reaction. During the addition of these carbonyl compounds, no dei the same temperature rise or course observed as under the conditions of Example 1, where none additional heat supply was not required. in the example 2, the temperature had to be increased to 150 ° C after the addition of the Carbonylver bond and constant for 2 hours be held before the reaction product was cooled abge.

Thereafter, the cooled reaction liquid wedge was withdrawn and used with such an amount of motor petrol hydrocarbons diluted that the solution had a volume of 3.2 l. It could then with dei the same amount of organically bound aluminum metal per liter as in Example 1 can be calculated

JO which amount is usually around 50g per l.itei Stabilizer lies. While in Example 1 a molar ratio of hydroxyl to ketone or carbonyl groups of 1384: 1 was used, this ratio in this example was 0.692: 1. It is clear that the crowd

of organically bound aluminum in the amount of ai butyl alcohol originally used - calculated ii Moles of OH - is not proportional. With the stabilization according to this example, the amount of organize! bonded aluminum, d. H. Al metal in an enolate bond and bonded directly to carbon Shape, relative to the hydroxyl-bonded metal, be larger than in Example 1.

With the aluminum stabilizer according to example: 2 stabilized iron pentacarbonyl standards j solutions prepared in a manner analogous to Example 1

Type A:

30 ml of aluminum stabilizer according to Example 2 were dissolved in 50 ml of unleaded car gasoline, and this solution was mixed with 20 ml of iron pentacarbonyl so that 100 ml of stabilized standard solution was obtained. 6 ir this standard solution were diluted with 1 l of unleaded motor gasoline A solution containing 0.5 g of iron and 0.150 g of aluminum per liter of gasoline is obtained, in which the ratio of Fe: Al be 55.4: 1 was.

The storage stability of this mixture was mi that of the mixture according to Example 1 type / comparable.

Type B:

The stabilizing standard solution of iron carbonyl was prepared analogously to Example 1 De The difference to this was that the cobalt saline used was cobalt naphthenate with the same metal content det wure. The shelf life in the presence of voi Iron or copper filings were also satisfactory here.

Example 3

In the same apparatus as in Example 1, 17MoI (1498.6 g or 1836.5 ml) of isoamyl alcohol (optically active form) were reacted with the stoichiometric amount of metal in the presence of 2 kg of aluminum pellets. Since this alcohol reacts more slowly than n-butanol, the addition had to be made more slowly, preferably at a rate of 100 ml per 15 minutes. A constant temperature of about 150 ° C. was maintained during this process. After all of the alcohol was added, a mixture of 500 ml of ethyl acetate (450.5 g) and 500 ml of acetylacetone (488 g) was added. This addition was extended over 3 hours, the temperature being kept constant at 150 ° C. Thereafter, the temperature was increased atf 170 ⁰ C and 2 hours long held constant, after which the mixture was cooled. After the cooled reaction mass was allowed to run off or drawn off, it was diluted with so much unleaded automotive gasoline that a volume of 3500 ml was obtained. The amount of organically bound aluminum was found to be 50 g / l.

Starting from this stabilizing solution, two stabilized iron pentacarbunyl solutions were again made as standard solutions with 8.311 g of iron per 100 ml of standard solution, corresponding to an iron pentacarbonyl content of 20%.

Claims (1)

Patent claims: 1. Solutions of iron carbonyls in gasoline hydrocarbons stabilized with organoaluminum compounds, characterized in that they are reaction products of aluminum trialkoxides with one or more carbonyl compounds of the general formula as stabilizing organoaluminum compounds