DE3826797A1 - FUEL COMPOSITIONS CONTAINING POLYCARBONIC ACIDIC LOW-CHAIN ALCOHOLS - Google Patents

Description

The invention relates to fuels for internal combustion engines with improved properties containing esters of aromatic Di-, tri- or tetracarboxylic acids and long-chain alcohols.

In particular, the invention relates to fuel compositions for Otto Engines.

It is known that by adding various additives to the gasoline the Cleanliness of carburetors, injectors, intake manifolds and intake valves improve and reduce the emissions of undesirable components of the exhaust gases can thereby reduce. In general, so-called gasoline is used Additive packages in quantities up to 2500 mg / kg. These exist in the general from detergents, corrosion inhibitors, oxidation inhibitors, anti-icing agents, carrier oils and solvents.

Carrier oils have the main task, the so-called valve plug prevent and improve the distribution of detergents. In addition, polyethers and esters as carrier oils are said to increase the Octane requirement of engines with increasing number of operating hours to decrease.

The use of esters as a gasoline additive has long been known. Your Use as a gasoline additive is e.g. described in DE-OS 21 29 461. The esters mentioned there are, as in the cited patent expressly mentioned, thermally unstable.

It has now surprisingly been found that thermally stable esters with high molecular weight excellent carrier oils, which up to 30%, the usual detergents can be saved without the Gasoline quality, i. the cleansing effect in the intake and mixture education system, worsened.

Accordingly, the invention provides fuel compositions, the a low content, e.g. 0.005 to 0.2% by weight, based on the total to esters of aromatic di-, tri- and tetracarboxylic acids with long-chain aliphatic, only carbon, hydrogen and oxygen containing alcohols, wherein the total carbon number of the Esters at least 36 carbon atoms and the molecular weight 550 to 1500, preferably 600 to 1200.  

The esters to be used are prepared in a conventional manner by esterification or transesterification. Suitable aromatic di-, tri- or tetracarboxylic acids are o-phthalic acid, isophthalic acid, terephthalic acid, trimesic acid, trimellitic acid and pyromellitic acid. Of these, o-phthalic acid is preferred. As alcohol components are alcohols with usually more than 13 carbon atoms, especially oxo alcohols from higher olefins, for example, oligomers of butene such as tetrameric to octameric, ds C₂₁-, C₂₅-, C₂₉- and / or C ₃₃ -oxo alcohols and oxo oils, The residues of Oxoalkoholdestillation the production of higher alcohols such as nonanol to pentadecanol.

Fuel for combustion engines is understood to mean organic, mostly predominantly hydrocarbon-containing liquids used for the Operation of petrol, Wankel and diesel engines are suitable. Next Fractions of crude oil processing are also hydrocarbons of coal hydrogenation, alcohols of various origin and composition and Ethers such as e.g. Methyl tertiary butyl ether contained therein. The permissible Mixtures are usually nationally determined worldwide.

The inventively used esters are the fuels generally together with detergents such as amides of oleic acid, ethylenediamine tetraacetic acid according to EP-A-6 527 or polyisobutenylsuccinic, and in particular polybutene with NH ₃ , aminoethylethanolamine, Di methylaminopropylamin, triethylenetetramine, tetraethylenepentamine, such as They are described in US-A-32 75 354, DE-A-21 25 039, EP 2 44 616, corrosion inhibitors, ds usually low molecular weight compounds having amide and / or ammonium and / or amine and / or acid groups or triazole - As well as imidazole derivatives, phenolic or amine antioxidants, such as di-tert-butylphenol or paraphenylenediamine and anti-icing agents, such as alcohols or diols added. In this case, the combination of the esters to be used according to the invention with polybutene amines is preferred, wherein the quantitative ratio of the esters to the polybutene amines is generally from 1: 2 to 3: 1. A carrier oil combination with polyethers or mineral oil comes into consideration; this allows for a reduction in the proportion of ester relative to the polybutene amines or amides.

Although the reasons for the effect of the esters to be used are not in the Individual can be found that the effectiveness itself increased with increasing molecular weight. As a result, the lower one Molecular weight limit is not sharp and the upper limit alone by the Viscosity, handling and availability of the alcohols are determined.

In the following examples, the preparation and use of some representative ester explained.

Production Example A

1180 g of oxo-oil from the cobalt-catalyzed preparation of iso-nonanol, having an acid number of 8, an OH number of 138, a saponification number of 62 and a CO number of 1.2, are treated with 163 g of phthalic anhydride, 0.25 g of tetrabutyl orthotitanate and 150 g of toluene are refluxed for 20 h on a water separator. This 22 ml of water are separated. The acid number drops to 1.1. The mixture is cooled, neutralized with 5% Na ₂ CO ₃ solution and added dropwise at 130 ° C and 70 mbar 1 kg of water in 3 hours (steam distillation). This gives 908 g of an ester mixture having the following properties:

Acid value | 0.3 OH number 9.4 saponification 170 Refractive index at 20 ° C 1.4730 Density at 20 ° C 0.9349 g / cm³ Viscosity at 20 ° C 179 mm² / s decomposition beginning 215 ° C decomposition end 325 ° C

Production Example B

1150 g of oxo oil from the cobalt-catalyzed preparation of iso-decanol with an OH number of 154, an acid number of 0.76, a saponification number of 36 and a CO number of 1.8, with 208 g of phthalic anhydride, 0.2 g Tetrabutylorthotitanate and 150 g of toluene for 36 h at Wasserauskreiser below Reflux heated. This separates 28 g of water and the acid number decreases to 2. After neutralization, washing and steam distillation 1043 g of an ester mixture are obtained, which are characterized as follows:

Acid value | 0.1 OH number 5.4 saponification 166 Refractive index at 20 ° C 1.4777 Density at 20 ° C 0.9370 g / cc Viscosity at 20 ° C 603 mm² / s decomposition beginning 245 ° C decomposition end 330 ° C

In the same way, the esters for experiments 8 and 11 were prepared.  

In the following table is the effect of known carrier oils and the Esters to be used according to the invention also in combination with known Detergents in gasoline for combustion engines shown. The in the Table indicated amounts of the esters were unleaded premium gasoline (RON 95, DIN 51607) added and test bench tests with a 1.2 l Opel cadet engine according to CEC-F-02-T-79 performed. As engine oil was the reference oil RL 51 used.

Table 1

The table shows one increasing with the molecular weight of the ester Effect on the inlet valves of the 1.2 liter Opel cadet.

Experiments 2 through 4 of the table show a gradual reduction in intake valve deposits versus operation with no addition fuel (Experiment 1). For Run 2, a Solvent Neutral 500 with a viscosity of 17 mm ² / s at 100 ° C was used. In Experiment 3, a polypropylene glycol having a viscosity of 100 mm ² / s at 40 ° C was used. The esters, some of which have significantly lower viscosities, alone show a far better effect. Experiments 4 to 8 are esters of high purity, ie OH number less than 1, acid number less than 0.1 and ash less than 1 mg / kg. The C₂₅-phthalate was prepared with an alcohol obtained by hydroformylation of a hexa-iso-butene from the preparation of reactive polyisobutene according to DE-AS 27 02 604. The viscosity of this ester is 31 mm ² / s at 100 ° C.

For the Oxoölester no molecular weights are given, since it is chemically is not a uniform substance. Rather, lie Substance mixtures, which still Monocarbonsäureester, ethers and coals low molecular weight hydrogen. The main effect However, it starts from the diesters of higher alcohols, which are in the Oxoölen are included.

The combination of the carrier oils to be used according to the invention with commerce conventional polybutene amine prepared from polybutene MG 1300 and aminoethyl ethanolamine, active substance content 50% shows the synergistic effect of Ester formulations compared to a polyether formulation. The recommended dosage of commercial polybutene-amine is for Formulations with mineral oil 350 mg / kg. In contrast, the inventive esters a saving of about 30%, of polymeric Detergent. Results with other detergents of higher viscosity comparable.

Claims (4)

1. fuels for internal combustion engines containing 0.005 to 0.2 wt .-%, based on the fuels, on esters of aromatic di-, tri- or Tetracarboxylic acids with long-chain aliphatic alcohols, wherein the Total carbon number of the esters at least 36 C-atoms and the Molecular weight is 550 to 1500. 2. fuels according to claim 1, characterized in that the esters as alcohol component C₂₁-, C₂₅-, C₂₉- and / or C₃₃-oxo alcohols Oligomerbutenen or polyisobutenes with high vinylidene content contain. 3. fuels according to claim 1, characterized in that the esters as alcohol component distillation residues of the hydroformylation of olefins. 4. fuels according to claim 1, characterized in that they are next the esters detergents, anti-icing agents, corrosion inhibitors and antioxidants.