WO2013072479A1

WO2013072479A1 - Conductive di-tert-butyl peroxide (dtbp) preparation as a diesel additive

Info

Publication number: WO2013072479A1
Application number: PCT/EP2012/072878
Authority: WO
Inventors: Sven Gutewort
Original assignee: United Initiators Gmbh & Co. Kg
Priority date: 2011-11-16
Filing date: 2012-11-16
Publication date: 2013-05-23
Also published as: DE102011086515A1

Abstract

The invention relates to the use of a conductive DTBP preparation as a fuel additive and in particular as an additive for diesel fuel.

Description

CONDUCTIVE DI - ER. - BUTYLPEROXIDE (DTBP) - PREPARATION AS DIESEL ADDITIVE

description

The present invention relates to the use of safely-handled conductive di-tert-butyl peroxide (DTBP) formulations as a fuel additive, and more particularly as an additive to diesel fuel.

The cetane number is a characteristic parameter for the combustion quality of diesel fuel. The cetane number is a measure of the ignition or the ignition delay, ie the time between the start of the fuel injection and the beginning of the combustion. Favorable is a rapid ignition, followed by a uniform and complete combustion as possible. The higher the cetane number, the shorter the ignition delay and the better the combustion quality.

To increase the cetane number, various additives are used. On a commercial scale, almost exclusively 2-EHN (2-ethylhexyl nitrate) is currently used. The problem with this additive is its high toxicity, its poor storage stability, safety-critical properties and considerable additional costs. In particular, due to its explosiveness, the use of 2-EHN is problematic. Furthermore, the nitrogen content can lead to increased, unwanted NOX emissions.

Cetane number increasing additives are also described, for example, in US 2,763,537, including acyl nitrates, nitrites, nitroso compounds, diazo compounds and organic peroxides. Organic peroxides are currently not commercially used as diesel additives with the exception of small amounts of DTBP (di-tert-butyl peroxide). This for cost, security and compatibility reasons. For example, commercially available peroxide preparations often contain substantial amounts of water as phlegmatizers, are thermally or chemically unstable, can not be used commercially as fuel additives because of the raw materials or production processes used, or contain aromatic radicals which negatively influence pollutant emissions. Water-stabilized peroxides are unsuitable as a fuel additive, since water does not mix with the fuel, but forms a two-phase system.

Organic peroxides are thermally labile compounds that decompose exothermically with cleavage of the peroxide oxygen-oxygen bond. Therefore, for safety reasons, organic peroxides often have to be phlegmatized for safe handling or safe transport or are already produced technically in dilution.

DTBP has an extremely low conductivity of <3 pS / m. Safety aspects limit the use of DTBP in larger quantities as a fuel additive.

An object of the present invention was to provide an improved fuel additive, particularly in terms of manageability and safety aspects.

The invention therefore relates to a fuel comprising a conductive di-tert-butyl peroxide (DTBP) preparation as an additive.

The invention also relates to a fuel additive comprising a conductive di-tert-butyl peroxide (DTBP) preparation. DTBP, since it is thermally stable, can be prepared as a pure substance, in particular with a purity of> 98% by weight, more preferably> 99% by weight and even more preferably> 99.3% by weight. In principle, DTBP with a lower content can also be used specifically for combustion processes if this DTBP quality can be produced at lower costs and it is ensured that this DTBP quality has no adverse effects on the fuel, such as increased water or acid content.

According to the invention, a conductive DTBP preparation is used in which a conductivity-improving additive is added to the DTBP. Preferably, the amount of added conductivity-improving additive is at most 10% by weight, in particular at most 5% by weight, preferably at most 1% by weight, more preferably up to 0.5% by weight and even more preferably up to 0.1% by weight %, based on the total weight of the DTBP preparation. The amount of conductivity-improving additive is furthermore preferably at least 0.001% by weight, more preferably at least 0.005% by weight and in particular at least 0.01% by weight, based on the total weight of the DTBP preparation. More preferably, the additive is 0.1 to 100 ppm, more preferably 0.5 to 50 ppm, and most preferably 1 to 10 ppm. According to the invention, it is preferred to add so much conductivity-improving additive that the conductivity of the DTBP preparation is 50 pS / m, more preferably> 500 pS / m and even more preferably> 1000 pS / m.

Suitable conductivity-improving additives are, for example, organic acids and their salts, inorganic acids and salts thereof and mixtures thereof. Suitable organic acids are, for example, polymeric compounds which contain one or more sulfuric acid groups, sulfonic acid groups, carboxylic acid groups, phosphoric acid groups or phosphonic acid groups. Other suitable organic acids are sulfuric acids, sulfonic acids, carboxylic acids, phosphoric acids or phosphonic acids or hydrates thereof, which have at least one Ci-C ₃₀ hydrocarbon radical, in particular one or more _Ci-C2 o alkyl radicals, C ₂ -C ₂₀ - alkenyl, C ₆ -C ₈ -aryl, C ₇ -C ₃ o-aralkyl or C ₇ -C ₃ O-alkaryl radicals. The hydrocarbon radicals may include one or more hydroxy, alkoxy, carboxyamide or ester groups.

Conductivity-improving salts of organic acids are, for example, ammonium or quaternary ammonium sulfates, ammonium sulfonates, ammonium and quaternary ammonium carboxylates, ammonium and quaternary ammonium phosphates or ammonium and quaternary ammonium phosphonates which contain one or more C ₁ -C 30 -hydrocarbon radicals in the anion or / and cation as defined above. Suitable conductivity enhancing salts of inorganic acids are, for example, ammonium or quaternary ammonium halides, which may have one or more CiC ₃ o-hydrocarbon radicals, as defined above. Particularly preferred conductivity-improving additives are para-toluenesulfonic acid monohydrate, dodecylbenzenesulfonic acid, ethoxylated and phosphated nonylphenol, copper or chromium dialkyl salicylate, sodium (sec-C ₃ -C ₇ -alkyl) sulfonate, sodium or calcium dialkylsulfosuccinate, di (hydrogenated tallow) dimethylammonium methosulfate, didecyldimethylammonium chloride, polymeric compounds containing sulfonic acid groups, sulfonate groups and / or sulfone groups or polymeric compounds containing carboxylic acid groups and / or amide groups.

With particular preference the conductive DTBP preparation used according to the invention comprises dodecylbenzenesulfonic acid for

Conductivity improvement. With particular preference, the conductive DTBP preparation according to the invention comprises at least one quaternary ammonium compound for conductivity improvement. The amount of dodecylbenzenesulfonic acid is preferably 0.1 to 100 ppm, more preferably 1 to 10 ppm, based on the amount of DTBP. The amount of quaternary ammonium compound is preferably 0.1 to 100, more preferably 1 to 10 ppm, based on the amount of DTBP.

The conductive DTBP preparation used according to the invention is preferably anhydrous. Anhydrous here means that the content of water in the composition is <5% by weight, in particular less than 1% by weight and even more preferably <0.3% by weight.

Surprisingly, it has been found that a conductive DTBP preparation is suitable as a fuel additive. In particular, the use of DTBP as an additive increases the cetane number of the fuel, and preferably raises it above the base fuel by a value of at least 2, more preferably at least 3, even more preferably at least 4 and most preferably at least 5. The cetane number can be determined, for example, according to ASTM 0613. Increasing the cetane number is a measure of improving the ignitability of the fuel.

Furthermore, it has been found that with the same consumption, the pollutant emission, in particular the hydrocarbon emission and / or the carbon monoxide emission, is significantly lowered, at the same time the NOx emission is not significantly increased. These advantages are obtained in vehicles without catalyst, but surprisingly also in vehicles with catalyst. Surprisingly, reduced pollutant emissions were detected both before a downstream catalytic converter and after a downstream catalytic converter. A reduction of pollutant emissions downstream of the catalytic converter was found especially in Phase 1 (Cycle 1 to 4) of the NEDC drive cycle, in which low speeds of up to 50 km / h are used and in which the catalytic converter has not yet reached the full operating temperature. Thus, conductive DTBP and blends thereof are also of great interest in regions where the catalyst density in the existing vehicle fleets is already very high, such as Europe, since there are a lot of trips with vehicles where the catalyst does not reach full operating temperature , Conductive DTBP and blends thereof as a fuel additive consequently reduce pollutant emissions, particularly hydrocarbon and carbon monoxide emissions, independently of the spread of catalytic converters.

For vehicles operated without a catalytic converter, pollutant emission in phase 1 (cycle 1 to 4) of the NEDC driving cycle is higher than in phase 2 (cycle 5). In Phase 1, the reduction of hydrocarbon and carbon monoxide emissions with fuels containing conductive DTBP as an additive is particularly high. This is the desired effect, especially for short-distance traffic.

In principle, the pollutant emissions of e.g. Hydrocarbons and carbon monoxide in the combustion of low grade fuels higher than higher quality fuels.

It has now surprisingly been found that conductive DTBP as an additive, the pollutant emissions of eg hydrocarbons and Carbon monoxide when using higher quality diesel, such as a commercial Euro4 diesel, more reduced than when using low-grade diesel, such as a commercial US diesel. In this respect, conductive DTBP is also particularly suitable, for example, as a fuel additive for regions in which typically higher quality fuel grades are used.

By using anhydrous DTBP, which is miscible with diesel fuel, it is avoided that forms an undesirable second aqueous phase. It is possible to use DTBP as an additive in an anhydrous organic solvent. Polar and non-polar solvents can be used. Examples of suitable non-polar solvents are alkyls and in particular aliphatic hydrocarbons, preferably aliphatic hydrocarbons having 4 to 16 C atoms, even more preferably having 6 to 14 C atoms, most preferably having 7 to 12 C atoms and in particular isododecane, isooctane, Decane, nonane, n-octane and / or heptane or mixtures of different aliphatics. Examples of polar solvents are, in particular, oxygen-containing solvents, such as, for example, alcohols or / and ethers. Alkyl alcohols are preferably used as solvents, in particular C 1 -C 8 -alkyl alcohols, more preferably C 2 -C 6 -alkyl alcohols, even more preferably butanol and most preferably tert-butanol. By using alcohols, and especially tertiary butanol, the oxygen content in the fuel additive is further increased, which is desirable and contributes to combustion enhanced by oxygen enrichment and thus reduction of pollutant emissions. Particularly preferred are C6-C14 aliphatic hydrocarbons. Further particularly preferred solvents are ethers and polyethers, particularly preferably aliphatic or cyclic ethers and / or polyethers.

The amount of DTBP in the additive is preferably at least 10% by weight, preferably at least 30% by weight and in particular at least 50% by weight. More preferably, the amount of DTBP in the additive is at least 70 weight percent, more preferably at least 90 weight percent, and most preferably at least 99 weight percent. Pure DTBP is preferred, ie in particular a DTBP additive which does not comprise a solvent. However, the amount of DTBP in the additive can also be up to 90% by weight or up to 75% by weight or up to 60% by weight.

The proportion of anhydrous organic solvent is more preferably 0% by weight, but the proportion may also be corresponding to at least 0% by weight, more preferably at least 25% by weight and most preferably at least 40% by weight and up to 90% by weight. , more preferably up to 70% by weight, and most preferably up to 50% by weight.

The fuel according to the invention may contain as base fuel known fuels or fuels, such as gasoline, especially gasoline, super etc., diesel fuels such as diesel, biodiesel or similar, but also very low diesel qualities, such as various marine diesel, rapeseed methyl ester, oxymethylene ethers, kerosene or rocket fuels. Preferably, the base fuel is a diesel fuel. By the additive according to the invention, in particular the ignitability of the fuel is increased. Furthermore, the emission of soot and hydrocarbons in the internal combustion engine is significantly reduced. The conductive DTBP preparation used according to the invention as an additive is also significantly easier to handle in terms of safety than the additives usually used. Compared with the conventionally used 2-EHN, the use of DTBP as additive according to the invention similarly improves the combustion. Further, DTBP contains no nitrogen, so that the associated problems and in particular the problem of the formation of nitrogen oxides are reduced according to the invention. Furthermore, DTBP is significantly safer in terms of safety than 2-EHN, especially in terms of decomposition.

A measure of the rate of decomposition and pressure build-up in the decomposition of a product is the Koenen test. The larger the Koenen value, the more violent the decomposition takes place.

Thus, the Koenen for 2-EHN = 1, 0, while the Koenen for a conductive DTBP is <1.

Also, the energy released in the decomposition of 2-EHN is significantly higher with ΔΗ = 2210 J / g than that of DTBP with ΔΗ = 1370 J / g.

The conductivity of pure DTBP is extremely low at <3 pS / m, so that DTBP replenishment processes are very critical in terms of safety due to possible charge separations, since these charge separations can generate sufficient ignition energy to ignite DTBP since DTBP has only a very low ignition energy of < 0.1 mJ needed. The use of conductive DTBP preparations eliminates this disadvantage. In particular, the conductive DTBP preparations used according to the invention have a conductivity of> 50 pS / m, preferably> 500 pS / m and even more preferably> 1000 pS / m. In the present invention, the fuel is preferably 0.001 wt% to 10 wt%, more preferably 0.05 wt% to 5 wt%, and most preferably 0.01 wt% to 2 wt% DTBP. According to the invention, it has been found that a reduction in pollutants can already be achieved with small amounts of additive. Accordingly, the fuel preferably has up to 0.5 wt% DTBP, more preferably up to 0.3 wt% DTBP and most preferably up to 0.2 wt% DTBP.

Particular preference is given to using an electrically conductive variant of the DTBP (DTBP-S-500 from United Initiators) as an additive which avoids the safety-critical handling of the DTBP with regard to the static charge.

It is also possible according to the invention to combine the additive containing DTBP according to the invention with other additives. Preferred is e.g. the combination with other peroxides and especially with tert-butyl hydroperoxide (TBHP). Particularly preferred is an additive comprising TBHP and DTPB.

The weight ratio of TBHP and DTPB is preferably from 10:90 to 90:10, in particular from 20:80 to 80:20 and particularly preferably from 30:70 to 70:30.

Preference is given to using a conductive DTBP preparation in combination with tert-butyl hydroperoxide (TBHP), in particular with anhydrous TBHP as fuel additive. Anhydrous means that the content of water in the TBHP composition is <5% by weight, in particular <1% by weight, even more preferably <0.3% by weight.

By using anhydrous TBHP, which is miscible with diesel fuel, it is avoided that forms an undesirable second aqueous phase. TBHP is preferably used as an additive in an anhydrous organic solvent. Polar and non-polar solvents can be used. Examples of suitable nonpolar Solvents are alkyls and in particular aliphatic hydrocarbons, in particular isododecane, isooctane, decane, nonane or / and n-octane or mixtures of various aliphatics. Examples of polar solvents are, in particular, oxygen-containing solvents, such as, for example, alcohols and / or ethers and / or polyethers. Alkyl alcohols are preferably used as solvents, in particular C 1 -C 8 -alkyl alcohols, more preferably butanol and most preferably tert-butanol. By using alcohols, and especially tert-butanol, the oxygen content in the fuel additive is further increased, which is desirable.

Especially when using a fuel additive additionally comprising TBHP in tert-butanol (TBA), a significant reduction in soot and pollutant emissions was observed.

Particularly suitable and thus most preferred for combination with a conductive DTBP preparation, an additive has been found, which 10 to 90 wt.%, In particular 30 to 70 wt.% TBHP in 90 to 10 wt.%, In particular 70 to 30 Wt. Contains% tert-butanol. The phlegmatization of TBHP in an oxygenated solvent, and especially in tertiary butanol, increases safety during TB TB technical production, transportation, and further handling.

Based on the phlegmatization with an oxygen-containing solvent, in particular tert-butyl alcohol, the oxygen content of the additive is also increased to reduce pollutants in the exhaust gas.

Furthermore, a fuel additive is also referred to, which contains in addition to DTBP another known fuel additive, such as 2-EHN. The invention further relates to a fuel additive comprising a conductive DTBP formulation as described herein and the use of a conductive DTBP preparation to increase the cetane number. The invention furthermore relates to the use of a conductive DTBP preparation for pollutant reduction, in particular for reducing the emission of hydrocarbons or / and carbon monoxide.

The invention is further illustrated by the following examples.

example 1

Conductive DTBP preparation

To DTBP is added dodecylbenzenesulfonic acid (1 ppm) and a quaternary ammonium compound (1 ppm). The conductivity of the preparation obtained is> 1000 pS / m.

Example 2

A fuel comprising a conductive DTBP formulation A conventional US base diesel fuel has a cetane number of 45.2. To this fuel is added a conductive DTBP formulation (DTBP-S-500 from United Initiators) at a concentration based on DTBP of 0.05% by weight of additive and at a concentration of 0.5% by weight.

Compared to the basic fuel, the addition of the additive significantly increases the cetane number. When using the three fuels mentioned, ie Basic diesel, base diesel + 0.05 wt.% DTBP and base diesel + 0.5 wt.% DTBP, the cetane number is significantly improved without significant increase in consumption at the same engine power in the presence of the additive DTBP and significantly reduces the emission of pollutants. In particular, there is a significant reduction in hydrocarbon emissions and carbon monoxide emissions.

The cetane number of the conventional US base diesel fuel of 45.2 is increased to 47.6 by addition of 0.047 wt% DTBP S-500 and a total of 0.157 wt% DTBP S-500 added to 55.4.

Comparative emission and fuel consumption measurements were taken on a conventional US base diesel fuel (cetane number 45.2) with and without DTBP S-500 additive on a chassis dynamometer according to the standard NEDC driving cycle.

The test vehicle was a Mercedes C 220 CDI, 4 cylinders, 1 10 KW power, built in 2005 with a 5-speed automatic transmission and a mileage of about 140,000 km used. The vehicle is equipped with a particulate filter and catalytic converter. The raw emissions were determined in multiple measurements before and after the catalyst.

By adding 0.193% by weight of DTBP S-500 to a conventional US base diesel with a cetane number of 45.2, it was possible to lower the raw emissions upstream of the catalytic converter as follows, while maintaining average fuel consumption:

US base diesel

Measured values before 0.193% by weight DTBP S-500

Phase 1 Phase 2

the catalyst (cycle 1 - 4 NEDC) (cycle 5 NEDC)

Hydrocarbons (HC) -20.8% -4.4%

Carbon monoxide (CO) -18.0% -8.7%

Carbon dioxide (CO2) 0.0% 0.0% Particularly important and pronounced is the positive influence of emission reduction in phase 1, the cold start phase in NEDC cycle 1 to 4.

Especially in Phase 1 (Cycle 1 - 4 NEDC), a very strong reduction in emissions downstream of the catalyst was also measured, since this does not yet have the required operating temperature:

US base diesel

The ΝΟχ emissions increase below the measurement tolerance.

Example 3

A fuel comprising a conductive DTBP formulation and TBHP as an additive

A conventional US base diesel fuel is admixed with an additive consisting of 27.5 wt% TBHP, 22.5 wt% TBA and 50 wt% DTBP S-500.

Blend 1 contains 0.013 wt% TBHP and 0.024 wt% DTBP S-500. Mixture 2 contains 0.052% by weight of TBHP and 0.094% by weight of DTBP S-500.

The CETAN number of the conventional base diesel fuel is 45.2, that of mixture 1 is 47.9 and that of mixture 2 is 56.7. Compared to the basic fuel, the cetane number is significantly increased by the addition of the additive and, according to the following table, the pollutant emissions are significantly reduced while the consumption remains constant, and even more significantly in phase 1.

US base diesel

US base diesel

The ΝΟχ emissions increase below the measurement tolerance.

Compared to the basic fuel, the addition of the additive significantly increases the cetane number. When using the three fuels mentioned, ie base diesel, base diesel + 0.05 wt.% DTBP and base diesel + 0.5 wt.% DTBP, the cetane number is significantly improved without significant increase in consumption at the same engine power in the presence of the additive and at the same time Pollutant emission significantly reduced. In particular, there is a significant reduction in hydrocarbon emissions and carbon monoxide emissions. Example 4

2-EHN and DTBP were mixed with a US base diesel, the cetane numbers were measured and the exhaust gas behavior was investigated.

For the cetane numbers, the following results have been obtained:

The emissions tests were carried out with the following additive additives:

The following values were determined:

Pollutant fuel analysis values in each case in mg / kg before c Jem nac i the Katal sator Katal ysator phase phase Phase Phase 1 2 1 2

US base diesel 587.4 393.8 101, 6 12.8

Carbon THBP-55 / DTBP S-

454.7 377.3 57.9 14.4 hydrogen 500

Reduction 22.6% 4.2% 43.0% -13.0%

US base diesel 1025.9 533.8 315.2 5.7

THBP-55 / DTBP S-

Carbon monoxide 800.1 470.2 190.6 5.7

500

Reduction 22.0% 11, 9% 39.5% -0.5%

REF - - 79.4 1 18.5

NOX CAND 86.3 122.3 80.9 120.8

Reduction - - -1, 9% -1, 9%

US base diesel 587.4 393.8 101, 6 12.8

Kohlen¬

DTBP S-500 465.0 376.4 62.1 13.0 hydrogens

Reduction 20.8% 4.4% 38.9% -1, 7%

US base diesel 1025.9 533.8 315.2 5.7

Carbon Monoxide DTBP S-500 841, 2 487.5 220.5 6.0

Reduction 18.0% 8.7% 30.0% -4.4%

US base diesel - - 79.4 1 18.5

NOX DTBP S-500 85.0 120.9 79.9 1 19.9

Reduction - - -0.7% -1, 2%

US base diesel 587.4 393.8 101, 6 12.8

Kohlen¬

2-EHN 425.4 343.0 63.0 12.0 hydrogens

Reduction 27.6% 12.9% 38.0% 6.1%

US base diesel 1025.9 533.8 315.2 5.7

Carbon Monoxide 2-EHN 820.2 469.9 243.8 6.0

Reduction 20.0% 12.0% 22.7% -5.2%

US base diesel - - 79.4 1 18.5

NOX 2-EHN 84.8 121, 3 80.2 120.3

Reduction - - -1, 0% -1, 5%

Claims

claims

A fuel comprising a conductive di-tert-butyl peroxide (DTBP) preparation as an additive.

A fuel comprising a conductive di-tert-butyl peroxide (DTBP) preparation as an additive according to claim 1,

characterized in that

the conductive di-tert-butyl peroxide (DTBP) preparation has a conductivity> 1000 pS / m.

A fuel comprising a conductive di-tert-butyl peroxide (DTBP) preparation as an additive according to claim 1 or 2,

characterized in that

the conductive DTBP formulation comprises one or more conductivity enhancing components.

A fuel comprising a conductive di-tert-butyl peroxide (DTBP) preparation as an additive according to any one of the preceding claims, characterized in that

the conductive DTBP preparation has one or more conductivity-increasing components in an amount of 0.1 to 100 ppm.

A fuel comprising a conductive di-tert-butyl peroxide (DTBP preparation as an additive according to any one of the preceding claims, characterized in that

which comprises the conductivity-enhancing component dodecylbenzenesulfonic acid or / and a quaternary ammonium compound.

A fuel comprising a conductive di-tert-butyl peroxide (DTBP) preparation as an additive according to any one of previous claims,

characterized in that

the DTBP is present in an amount of from 0.001% to 10% by weight, based on the total weight of the fuel.

7. A fuel comprising a conductive di-tert-butyl peroxide (DTBP) preparation as an additive,

characterized in that the base fuel is selected from diesel fuel, gasoline and rapeseed methyl ester, kerosene and rocket fuels

8. A fuel comprising a conductive di-tert-butyl peroxide (DTBP) preparation as an additive according to any one of the preceding claims, characterized in that

the fuel is selected from diesel fuel.

9. A fuel comprising a conductive di-tert-butyl peroxide (DTBP) preparation as an additive according to any one of the preceding claims, characterized in that

the fuel comprises a further additive, in particular tert-butyl hydroperoxide (TBHP).

10. A fuel comprising a conductive di-tert-butyl peroxide (DTBP) preparation as an additive according to any one of the preceding claims, characterized in that

the fuel comprises a further additive, in particular anhydrous butyl hydroperoxide (TBHP).

1 1. A fuel comprising a conductive di-tert-butyl peroxide (DTBP) preparation as an additive according to any one of the preceding claims, characterized in that the fuel comprises a further additive, in particular 2-EHN.

12. A fuel additive comprising a conductive di-tert-butyl peroxide preparation. 13. Use of a conductive di-tert-butyl peroxide preparation to increase the cetane number.

14. Use of a conductive di-tert-butyl peroxide preparation for the reduction of pollutant emissions.