DE822030C - Knock-proof mixture for engine fuel - Google Patents

Description

Engine Fuel Anti-Knock Mixture This invention relates to anti-knock compounds for engine fuel, the anti-knock lead compounds and Bromocarbons or B: hydrocarbons and chlorinated hydrocarbons included as cleaning agent.

Detergents are substances made with anti-knock lead compounds find use in fuels for internal combustion engines and during combustion generate volatile lead compounds that are expelled by the engine. cleaning supplies reduce the amount of less volatile lead compounds that are otherwise during from combustion and accumulate in the engine parts. For satisfactory Working with a blistered gasoline engine is using one Detergent is essential. Commercially available cleaning agents are ethylene dibromide and ethylene dichloride.

It was generally believed that detergents could be used during the Combustion process decompose or burn and hydrogen halides in freedom that react with the lead compounds and as in the American patents r 592 954 and Z 668 022 was shown, is the amount of halogen alone with tetraethyl lead is used, which is important from the point of view of operation of the motor. From this point of view, all detergents are given a given Amount of a given halogen is considered to be equally effective. It was on the contrary found that the effectiveness of a given amount of halogen in the engines to a large extent: can vary in degree if the fuel is in different chemical Compounds is fed and that the various factors responsible for the relative The value of various compounds is crucial, from their molecular structure depend.

Of the cleaning agents known so far, only have ethylene dibromide and ethylene dichloride found successful commercial use for years. Even though they generally meet the requirements well Cleaning agents, do not satisfy them for some work requirements of modern internal combustion engines completely, especially with machines that are used for high performance.

Efforts have been made to address this particular problem by choice of various compounds used as detergents to dissolve those in their boiling point came close to that of tetraethyl lead. However, the selection of a halide was in order Improvement of one property leads to a decrease in other properties. For example, it has been found that dibromochlorobutane, which because of its low Volatility was chosen when storing in a commercial manner with tetraethyl lead was far too unsustainable to be used in retail. Some detergents, the sufficient evaporation properties in engines and sufficient stability in knock-resistant liquids have insufficient miscibility with tetraethyl lead. Other detergents that have been suggested show im general deficiencies with regard to one or more of the above properties.

The object of the invention is to provide cleaning agents, which not only have a good cleaning effect, but also others for possess the properties required for trade.

In accordance with the invention, a knock-resistant mixture for engine fuel has been made elaborated, which consists of a non-knocking lead compound and one or more bromohydrocarbons consists of two or three bromine atoms and three to eight carbon atoms, with no more than one bromine atom attached to each carbon atom, and one Have a vapor pressure of 0.2 to 6 mm of mercury at 50 °. The mix also closes a chlorinated hydrocarbon with a vapor pressure of about 0.2 to 6 mm of mercury at 5o °. Due to a further improvement of the invention is called a bromohydrocarbon a dibromoalkane with four or five carbon atoms used if desired, with a dichloroalkane of four or five carbon atoms. Because of Another improvement of the invention is dibromotoluene as a bromohydrocarbon used, if desired, with a chlorinated hydrocarbon, preferably trichlorobenzene, together.

A typical group of bromohydrocarbons of our invention, with their vapor pressures in millimeters of mercury at 50 °, is the following: Approximately Bromocarbons vapor pressure at 5o ° 1, 3, 4-tribromopentane ............ 0.2 0.2 4,5-Dibromo-i, 3-dimethylbenzene ... i, 6-dibromohexane ............... 0.3 i, z, 5-tribrompentene-i .......... 0.3 1, 2, 3-tribromopentane ........... 0.4 Dibromotoluenes (mixed) ........ 0.5 1, 2, 3-tribromobutane ............. 0.7 3, 4-dibromomethylcyclohexane ..... 0.7 Approximately Bromocarbon vapor pressure at 5o " 6-Bromo-4- (bromomethyl) -hepten-i. . i, 2-dibromocyclohexane .......... 0.8 1, 2, 3-tribromo-2-methylpropane ... o, 8 1,2-dibromoheptane ....... ........ o, 8 1, 2, 3-tribromopropane ............ i, () 1,2-Dibromobenzene ............... i, 0 2, 5-Dibrompenten-i ............. 2.6 i, z-dibromohexene-i .............. 4.0 i, 2-i-bromocyclopentane. . ........ 4.6 1, 3-dibromo-2, 2-dimethylpropane. 5.5 2,3-Dibromo-2-methylenepentane .... I 6.3 Among the dibromoalkanes that can be used in the invention are i, i-Dibromobutane i, 3-Dibromopentane i, 2-Dibromobutane i, 4-Dibromopentane i, 3-dibromobutane i, 5-dibri) mpentane 1, 4-dibromobutane 2, 2-dibromopentane 2, 2-dibromobutane 2, 3-dibromopentane 2,3-Dibromobutane 2,4-Dibromopentane i, i-Dibromp2ntane 3, 3-Dil) rompentane i, 2-Dibromopentane i,, j-Dlbromo-2, 2- <Ii- mcth`Ilpropane. Mixtures of these compounds can of course be used; this is often more economical, since manufacturing processes result in mixtures and the challenges of isolating one compound from the other can be avoided.

Those for the implementation with (learn lead to form lead halide theoretically required amount of detergent containing two atoms of halogen per Atom is lead, one unit is called halogen.

One unit of any of the above compounds gives with tetraethyl lead good results in gasoline in vehicle engines.

The above list is only an example and does not include all Bromocarbons of our invention.

A typical group of hydrocarbons used with our hydrobromic hydrocarbons and their vapor pressure at 50- is as follows: Approximately Chlorinated hydrocarbons Vapor pressure at 5o i-chloronaphthalene ............... 0.2 (5-chloramyl) benzene ............ 012 i-Chlorundecane ................. 0.5 i, 8-dichloroctane ............. ... 0.5 1, 2, 3, 4-tetrachlorc5, clol) eritan .... 1,5 Hexachloropropylene .............. 1.6 i, 2, 4-trichlorobenzene ............ 2.0 1,2-dichloroheptane .............. 2.4 5, 6-dichloro-3, 3-dimeth @ -llie - \, ari ... 2.8 2,4-dichlorotoluene ............... 3.2 1,2-dichlorocyclohexane ........... 4.6 i-chlorooctane .................... 5, f> 3-chloro-2, 2, 3-trimethyl-lliexane ..... 5.8 Among the dichloroalkanes which can be used in this invention, there may be mentioned i, i-dichlorobutane 1,3-dichloropentane i, 2-dichlorobutane 1,4-dichloropentane i, 3-dichlorobutane 1,5-dichloropentane i, 4-dichlorobutane 2, 2-dichloropentane 2,2-dichlorobutane 2,3-dichloropentane 2,3-dichlorobutane 2,4-dichloropentane i, i-dichloropentane 3, 3-dichloropentane i, 2-dichloropentane i, 3-dichloro-2, 2-di- methylpropane. Half a unit of 1, 2, 3-tribromopropane and one unit of hexachloropropylene with tetraethyl lead in motor fuel give good results in road vehicles.

The above list is only one example of the chlorinated hydrocarbons, which can be used.

Our cleaning agents mixed with a non-knock lead compound were added to a wide variety of gasoline. The resulting fuels were in extensive tests in the laboratory and on the road on numerous engines used, including vehicle, high-performance aircraft engines and single cylinder engines, of the kind commonly used to test aircraft fuels. After completion of each work step, the examination of such engine parts showed that in the absence of a cleaning agent, our connections are adversely affected Always proven to be effective cleaning agents and with low work performance at least as good as those now on the market.

Current commercial practice is to have a unit Use bromine in aircraft fuels, while for ordinary motor fuels half a unit of bromine is used with one unit of chlorine. For those described below In engine tests, the detergents were used in amounts expressed in number of the units of halogen as used in commercial practice.

On the street, our cleaning agents are carried along with work high load used on a series of commercial trucks. 1, 2, 3-tribromopropane, in connection with hexachloropropylene, was mixed with tetraethyl lead and a Gasoline added, which was used in part of the series. A fuel that consisted of the same gasoline, and tetraethyl lead and a mixture of ethylene dibromide and ethylene dichloride as a detergent was included in the remainder of the series used. As the conditions except for the composition of the detergent were the same, there was some difference in lead deposition and corrosion of the engine to the diversity of the detergent. With each of the Trucks were worked 24 hours a day with a load of about 16,000 kg. The life of the exhaust valve, expressed in miles to the first two valve failures on each engine was, on average, 300.! o greater in the Trucks working with a fuel that contained our detergents, than with a fuel that is the commercial mixture of ethylene dibromide and ethylene dichloride contained. In operations with high loads of this type, the durability of the exhaust valves is a critical factor and improvements to the above size are of great concern to truck and bus owners as a result of reduction the maintenance costs and the longer usability of the vehicles in traffic in the street.

One of our cleaning agents was also mixed in the road service compared to a chlorine detergent containing ethylene dibromide and ethylene dichloride. 1, 4-dibromobutane, in connection with the chlorine cleaning agent hexachloropropylene, was mixed with tetraethyl lead and added gasoline. There were comparisons with the same gasoline that is a mixture of tetraethyl lead, ethylene dibromide and ethylene dichloride included, employed when driving on the road. The fuels were on trucks of the same standard make in operation with heavy loads many thousands of miles used. Our detergent had a good cleaning effect, as shown by measurements the deposits in the engine, by inspection and by increasing the service life of the exhaust valves, which amounted to approximately 150 per cent.

Our detergents have also been made with greatly improved effectiveness used in commercial aircraft engines that ran in conditions similar to those of were comparable when flying. For example, air-cooled high-performance aircraft engines worked with three different cleaning agents, namely ethylene dibromide, 1, 2, 3-tribromopropane and mixed dibromotoluenes; the last two are our detergents Invention. Each test duration was 120 hours with a fuel that was 4.6 cc Tetraethylene volume per 3.785 l and i, o unit of one of the abovementioned bromohydrocarbon cleaning agents contained. Checking the valves and spark plugs at the end of each trial period showed that achieved noticeably better results with our cleaning agents became. When ethylene dibromide was used the exhaust valves were very burned. When our detergents were used, no valve was burnt.

Also ethylene dibromide and dibromotoluene in concentrations of one Unit of bromine in a fuel containing 46 cc of tetraethyl lead were in an air-cooled High-performance aircraft engine compared with a test duration of 120 hours. Because Burns of the exhaust valves made it necessary to try out the fuel Containing ethylene dibromide, terminate after 10 hours. A tour of the engine showed significant debris, cavities and burns on all exhaust valves. On the other hand, when a fuel containing dibromotoluene was used, it ran the engine for the full 120 hours and the inspection after the end of the experiment showed no valve burns and only minor deposits. When running with Ethylene dibromide it was necessary to change the spark plugs every 10 to 12 hours, whereas when running with dibromotoluene there is no replacement the spark plugs was required and the spark plugs were still in good condition at the end of the run was.

We believe that the better results are partly the higher internal ones Cleaning effect, partly the distribution ratio within the various cylinders of the molor, which is denser than that of tetraethyl lead. These The assumption is corroborated by the results of two other types of engines. One type of engine related to the comparison of the internal cleaning effect and the other to the comparison the distribution properties of our detergents with those previously known Cleaning agents, especially cleaning agents previously used commercially.

In single cylinder laboratory engines, commonly used for studies on aircraft fuels and spark plugs, where no spreading problem can arise, a comparison has been made of the dry weight of the combustion deposit after prolonged operation with a unit of different bromine cleaners. This deposit weight may serve as a measure of the internal degradation effect. The following table shows the results obtained: deposit Detergents related to Ethylenedi- bromide = 100% 1, 3-dibromo-2, 2-dimethylpropane 9i i, 6-dibromohexane ............ 78 i, 2-dibromocyclohexane ........ 84 1, 2, 3-tribromopropane ... 79 1, 2, 3-tribromobutane .......... 88 1, 2, 3-tribromo-2-methylpropane. 80 Even when working with single-cylinder aircraft engines, 1,4-dibromobutane or 2,3-dibromobutane of all cleaning agents produced only 80 and 95% of the deposits in the combustion chamber, as found with ethylene dibromide, under the same conditions. A reduction in deposits on the exhaust valves and spark plugs was also found.

We believe that the superiority of our detergents in trucking and aircraft engine not only because of the higher internal cleaning effect, but rather is also due to improved evaporation characteristics. Sometimes in certain Types of engines a poor distribution of the tetraethyl lead within the various Cylinder encountered. While this poor distribution is more so in aircraft engines occurs, it creates a problem for people under certain working conditions and heavy-duty motor vehicles. If the distribution doesn't matter is, as is well known, a reduced durability of the engine is the result if the Used fuel either too little or too much detergent in proportion to the existing tetraethyl lead. Low durability of the engines occurs, if a cylinder has an excess or insufficient amount of detergent with respect to the tetraethyl lead present. Each of these moments can be a and can cause premature failure of the spark plugs if there is a lack of detergents be accompanied by excessive lead deposition.

The distribution ratio of the detergent in the engine cylinders can be quite different from that of tetraethyl lead. We found through measurements that even if the tetraethyl lead is in the flowing along the manifold Liquid is present in high concentration, our detergents the lead accompany more closely than the cleaning agents previously used.

To illustrate the relative amounts of the various bromohydrocarbons present in the liquid portion of the fuel flowing along the walls of the manifold, a currently manufactured, upside-down 8-cylinder motor vehicle was used with the liquid flowing along the walls of the branches of the manifold was collected from each pair of cylinders. This liquid was analyzed to determine its tetraethyl lead and detergent content. In all cases the same gasoline was used with 3 cc of tetraethyl lead per 3, 785 liters with one unit of bromine, and each operation was carried out under the same conditions as possible. The following tables give the units of bromine in relation to the lead present in the liquid for a typical group of our cleaning agents and, for comparison, the same list for various cleaning agents that do not belong to our invention. Unit: Bromine for <read lead Steam in the Cleaning agent pressure v`nn our invention mm H Ve'ro is r- g red with so 'total melt Fluid- speed i, 6-dibromohexane ............ 0.3 1.5 Dibromotoluenes (mixed) ..... 0.5 1.8 1, 2, 3-tribromobutane .......... 0.7 i, i 1,2-dibromocyclohexane ........ o, 8 i, i 1, 2, 3-tribromo-2-methylpropane. o, 8 1.2 1, 2, 3-tribromopropane ......... 1.0 o, 8 i, 2-dibromohexane-i ........... 4.0 0.7 1,3-dibromo-2, 2-dimethylpropane 5.5 o, 5 Cleaning agent a_ ß @ rhall> our invention t-bromocetane ................. 0.005 4.1 1, 2, 3, 4-tetrabromocyclopentane (), 03 3.8 1, 3-dibromopropane ....... .... 11.0 o, i Ethylene dibromide ............. 40.2 0.05 We use chlorinated hydrocarbons with a vapor pressure that is comparable to that of our bromine hydrocarbons in order to obtain a comparable distribution ratio. We found that these chlorine compounds are generally more stable than the corresponding bromine compounds, and we believe that the molecular Stn @@ a @. @ R is not such an important factor in the selection of chlorine cleaning agents.

Provisions were also made of the distribution of lead and tetraethyl the cleaning agent is made on the individual cylinders of a multi-cylinder engine. Half a unit of ethylene dibromide plus one unit of ethylene dichloride were used with half a unit of one of our bromine cleaners, i, 2, 3-tribromopropane, plus one unit of one of our chlorine cleaners, hexachloropropylene. The maximum difference in units of bromine among the cylinders was called Ä ethylene dibromide and ethylene dichloride containing -n mixture on average 22 °% o and in units of chlorine 150,! o. When mixed with our detergents it was the maximum difference in units of bromine only 8% and in units of chlorine only 6% / a. The difference between the cylinders in the ratio of our detergents to lead can be greater or lesser than in the above specification, depending on the : Engine, the working conditions of the engine and the specific cleaning agents used. Our cleaning agents give cheaper products under the most varied of working conditions Results.

The improved distribution ratio of our cleaning agents in in relation to that of the anti-knock lead compounds supports the assumption that the better, relative distribution in part for the better durability of the engines when in use of our detergents in truck and high-performance aircraft engines, where disruptions related to the distribution have occurred is responsible.

We found that the boiling point of a detergent was not a reliable one 'Measure of its evaporation in relation to the tetraethyl lead in the manifold of the Engine is. For example, of 1, 2, 3-tribromopropane, the one would be 20 higher Boiling point than tetraethyl lead, normally assume that it is less vigorously evaporates and an accumulation of bromine in the liquid on the walls the manifold would result in more than one unit. During operation of the engine, however, contains the liquid flowing on the walls of the manifold mainly less than one unit of bromine.

In addition to the above, further properties are listed, the cleaning agents should have commercial suitability. The durability when storing anti-knock liquids that contain detergents is extreme important for the loading and storage of such liquids, either on their own alone or mixed with petrol. Under normal storage and loading conditions Anti-knock liquids that contain lead compounds can be reduced to a small extent Dimensions decompose even if they contain highly stable detergents. If knock-resistant, leaded liquids or fuels containing them are be stored over a period of several years, especially at elevated levels Temperatures, a high stability of the anti-knock liquids is desirable.

When the anti-knock liquid decomposes, either lead salts will fall out or remain in solution in the liquid from which they can separate out, when the liquid is mixed with gasoline. The decomposition is from gas evolution that creates pressure that affects the drums and tankers. in the Case of more serious decomposition due to significant instability of the anti-knock liquid the pressure can rise to such a high level that leakage or The result is tearing of the container. Decomposition destroys some of the anti-knock properties the lead compounds in the liquid and therefore has the anti-knock effect, the anti-knock liquid when a certain volume is added to the gasoline expect is unsure.

If desired, the shelf life of the anti-knock liquid mixture can be increased by adding certain antioxidants such as e.g. B. the alkyl-substituted phenol of the American patent 2 361 3 77 can be improved over time. In contrast to the good stability of our cleaning agents, many of the bromohydrocarbons whose molecular structure does not match our patent description, such as B. 1, i, 2, 2-tetrabromoethane, so unstable with tetraethyl lead, even after the addition of antioxidants, that they are unsuitable for use in trade as cleaning agents.

Another required property for commercial cleaning agents is complete miscibility with the anti-knock lead compounds even at low levels Temperatures so that the mixture will not separate when exposed to cold weather is stored or processed. If desired, the lowest temperature can be used for complete miscibility by adding one in common. -n solvent next reduce. The same effect can also be achieved by using a mixture of two or more more detergents can be obtained instead of a single one.

Our cleaning agents can contain other lead compounds than tetraethyl lead be used, e.g. B. Tetrapropylblei, Dimethyldiäthylblei and Methyltriäthylblei. Where a mixture of anti-knock lead compounds is used, the detergent can be used from one of our bromocarbons or a mixture of two or more consist of them. It is common to use a mixture of anti-knock lead compound and making detergents and then adding this mixture to gasoline. However, the detergent and the anti-knock compound can also be used separately Fuel can be added.

For the purpose of comparison, the proportions are those in the above Examples of cleaning agents used have always been the same, e.g. B. a unit Bromocarbon for the lead compounds in jet fuel and a mixture from half a unit of hydrobromic hydrocarbon and one unit of chlorinated hydrocarbon for the lead compounds in engine fuels. The use of our cleaning agents however, it is not critical and therefore not through this information limited. For aircraft fuels, the best results have been obtained with proportions from 0.8 to 1.5 units and further deviations can be made will. For engine fuels, we recommend proportions of cleaning agents, as set out in U.S. Patent 2,398,281.

Claims (9)

PATENT CLAIMS: i. Anti-knock compound for engine fuel, which contains a lead compound which prevents knocking, characterized in that, that it contains one or more bromohydrocarbons, the two or three bromine atoms as well as three to eight carbon atoms, with no more than one bromine atom associated with each carbon atom, and having a vapor pressure of predominantly Have 0.2 to 6 mm of mercury. 2. Mixture according to claim i, characterized in that that they also have one or more chlorinated hydrocarbons with a vapor pressure of predominantly 0.2 to 6 mm of mercury at 5o '. 3. Mixture according to the claims i or z, characterized in that the bromine hydrocarbon is a saturated, aliphatic bromohydrocarbon, a cycloaliphatic bromohydrocarbon or an aromatic bromohydrocarbon. 4.: Mixture according to claim i, characterized characterized in that the bromohydrocarbons are composed of one or more dibromoalkanes consist of four or five carbon atoms. 5. Mixture according to claim 4, characterized characterized in that they also contain one or more chloroalkanes having four or five carbon atoms contains. 6. Mixture according to claims 4 or 5, characterized in that it contains i, 4-dibromobutane. Mixture according to claim i, characterized in that the bromohydrocarbon is dibromotoluene. B. Mixture according to claim 7, characterized characterized in that they also contain a chlorinated hydrocarbon, preferably trichlorobenzene, contains. 9. Mixture according to claims i to d, characterized in that the the anti-knock lead compound is tetraethylene lead.