DE102011079556A1 - Use of carboxylic acid esters, which are esters of polybasic carboxylic acid and/or esters of hydroxy-carboxylic acid, e.g. as energy carrier, preferably as propellant or fuel and as lamp oil, and for operating device and machines - Google Patents

Abstract

Use of carboxylic acid esters, which are esters of a polybasic carboxylic acid and/or esters of a hydroxy-carboxylic acid, as energy carrier, preferably as propellant or fuel, is claimed. Independent claims are also included for: (1) driving a vehicle, a machine, or a device, comprising (a) producing (i) carboxylic acid esters containing polyvalent carboxylic acids, preferably at least one carboxylic acid ester comprising tributyl aconitate, triethyl aconitate, triethyl citrate and tributyl citrate, (ii) carboxylic acid esters of hydroxy-carboxylic acids, preferably at least one ester comprising ester of gluconic acid, isoascorbic acid and/or lactic acid, and/or (iii) the above carboxylic acid esters, (b) incinerating the carboxylic acid ester in a combustion engine, and (c) using the obtained energy for driving the vehicle or operating the machine or the device; and (2) heating or storing the energy, comprising the steps (a), (b) and (d) using the obtained energy for heating, or storing in a suitable storage medium; and (3) generating electrical power, comprising the steps (a), (b), (e) converting carboxylic acid ester (s) into electrical power in a biofuel cell, and the step (c).

Description

The invention relates to the use of carboxylic acid esters as energy carriers.

There is a need for new energy sources. Energy sources are chemical substances whose chemical energy can be easily converted into other forms of energy by oxidation, for example by combustion. The fuels include fuels and fuels. The chemical energy of fuels is used to propel vehicles such as shipping and aerospace. The chemical energy of fuels is converted into internal combustion engines and used for example for driving motor vehicles. In addition, the energy of energy carriers can also be converted into electricity in fuel cells.

In the prior art, a variety of energy sources are known, for example, fossil fuels such as oil, coal and natural gas and energy from renewable resources, such as wood, biofuels and biogas.

Biogas is a combustible gas, which is produced by fermentation of biomass. The resulting gas is often used directly on site in a combined heat and power plant to generate electricity and heat. After removal of the CO2 content, so-called biomethane or biomethane can be used as fuel.

The use of a mixture of ethyl acetate, ethyl propionate and ethyl butyrate as a fuel and their analysis by means of the homogeneous charge compression ignition (HCCI) method was used by Contion F., et al. ((2011) Energy Fuels, 25 (4), 1497-1503 ).

It is the object of the present invention to provide a new energy source.

The invention relates to the use of carboxylic acid esters as energy carriers, in particular as fuel or fuel, characterized in that the carboxylic acid ester is the ester of a polybasic carboxylic acid and / or the ester of a hydroxy carboxylic acid. In particular, the invention relates to the use of esters of polybasic carboxylic acids as fuel.

Esters of polybasic carboxylic acids are known in the art. The use of esters of polybasic carboxylic acids as an energy source (or fuel) or fuel has not been described. Esters of polybasic carboxylic acids and / or the underlying carboxylic acids are obtained as by-products or wastes in various industrial processes. The stored in these substances chemical energy can be used by the inventive use. This is advantageous because the esters of polybasic carboxylic acids are formed during biodegradation processes and have a high energy content. As a result, they are non-toxic and easily biodegradable. The esters of polybasic carboxylic acids have a high flash point and are therefore safe to handle. In addition, esters of polybasic carboxylic acids are storage stable even at high temperatures, whereas at very low temperatures they still have a low viscosity. This is especially in comparison to known energy sources, such. B. diesel advantageous. Furthermore, the properties of the energy carrier z. B. when used as fuel in the automotive sector in many parts to meet the requirements. Combustion in conventional internal combustion engines can be carried out without further intervention in the engine technology by adapting the fuel properties of the energy carrier to the respective internal combustion engine (diesel or gasoline) during esterification by a suitable choice of an alcohol-acid mixture.

In a preferred embodiment of the invention, the carboxylic esters are used as lamp oil.

A particular embodiment of the invention relates to the use wherein the carboxylic acid is a dicarboxylic acid or tricarboxylic acid. Another particular embodiment of the invention relates to the use wherein the carboxylic acid is an alpha-hydroxy carboxylic acid. Another embodiment of the invention relates to the use wherein the carboxylic acid is simultaneously an alpha-hydroxy carboxylic acid and a di- or tricarboxylic acid.

In a preferred embodiment of the invention, a low molecular weight carboxylic acid is used, i. H. a carboxylic acid having a maximum of 10 carbon atoms, for example having 2, 3, 4, 5, 6, 7, 8 or 9 C atoms.

A particular embodiment of the invention relates to the use, wherein the carboxylic acid is selected from the series of carboxylic acids comprising lactic acid, glycolic acid, gluconic acid, malic acid, tartaric acid, gallic acid, isocitric acid, citric acid, alpha-hydroxycaprylic acid, ascorbic acid, isoascorbic acid and aconitic acid.

A further particular embodiment of the invention relates to the use, wherein the carboxylic acid is selected from the series of polybasic carboxylic acids comprising oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, Pimelic, suberic, fumaric, maleic, phthalic, isophthalic, terephthalic, aconitic, citric, isocitric and tartaric acids.

Another particular embodiment of the invention relates to the use wherein the carboxylic acid with one or more of the alcohols selected from the series of alcohols comprising methanol, ethanol, propanol, butanol, pentanol, hexanol, heptanol, octanol, nonanol and decanol and / or a polyhydric Alcohol is esterified. The alcohol may be a primary, secondary or tertiary alcohol. A preferred embodiment relates to the esterification with alcohols having either 2, 3, 4, 5, 6, 7, 8, 9 or 10 C atoms.

A particularly preferred embodiment of the invention relates to the use, wherein the carboxylic acid ester is selected from the series of carboxylic acid esters comprising tributylaconitate (TBA), triethylaconitate (TEA), triethyl citrate (TEC) and tributyl citrate (TBC).

The invention also relates to the use, wherein the energy carrier is a mixture comprising various carboxylic acid esters, preferably carboxylic acid esters of a di- or tricarboxylic acid and carboxylic acid esters of an alpha-hydroxy acid and preferably wherein at least one of the esterified carboxylic acids is an unsaturated carboxylic acid.

One embodiment of the invention relates to the use wherein the energy carrier comprises at least 70% by volume or 80% by volume of carboxylic acid ester, preferably at least 85% by volume or 90% by volume, particularly preferably at least 95% by volume or 97% by volume .-%.

One embodiment of the invention relates to the use, wherein the fuel comprises not more than 10% by volume, preferably not more than 5% by volume, particularly preferably not more than 3% by volume of water.

The composition may vary due to manufacturing. In particular, if no particular purity is required for the energy conversion, the isolated or prepared carboxylic acid esters can be used directly, which then optionally comprise further substances, for example by-products or impurities.

An advantageous embodiment of the invention relates to the use, wherein the energy carrier Oxinate for soot reduction and to improve the exhaust gas quality.

The invention relates to the use of esters of polybasic carboxylic acids and / or hydroxycarboxylic acids for driving vehicles, for operating equipment and machines, for heating and for converting into storable forms of energy with the aid of suitable storage media, for example batteries.

• a) Carbonsäureester von mehrwertigen Carbonsäuren, insbesondere ein oder mehrere Carbonsäureester ausgewählt aus der Reihe der Carbonsäureester umfassend TBA, TEA, TEC und TBC, und/oder
• b) Carbonsäureester von Hydroxycarbonsäuren, insbesondere ein oder mehrere Ester ausgewählt aus der Reihe der Ester der Gluconsäure, der Isoascorbinsäure und/oder der Milchsäure, und/oder
• c) Carbonsäureester ausgewählt aus der erfindungsgemäßen Verwendung,
• d) isoliert oder hergestellt sind und
• e) die Carbonsäureester oder Mischungen von Carbonsäureestern in einem Verbrennungsmotor verbrannt werden und
• f) die dabei freiwerdende Energie zum Antrieb eines Fahrzeugs oder zum Betrieb einer Maschine oder eines Geräts verwendet wird.

The invention also provides a method for driving a vehicle or a machine or a device

• a) carboxylic acid esters of polybasic carboxylic acids, in particular one or more carboxylic acid esters selected from the series of carboxylic acid esters comprising TBA, TEA, TEC and TBC, and / or
• b) carboxylic acid esters of hydroxycarboxylic acids, in particular one or more esters selected from the group of the esters of gluconic acid, isoascorbic acid and / or lactic acid, and / or
• c) carboxylic acid esters selected from the use according to the invention,
• d) are isolated or manufactured and
• e) the carboxylic acid esters or mixtures of carboxylic acid esters are burned in an internal combustion engine and
• f) the energy released is used to drive a vehicle or to operate a machine or a device.

• a) Carbonsäureester von mehrwertigen Carbonsäuren, insbesondere ein oder mehrere Carbonsäureester ausgewählt aus der Reihe der Carbonsäureester umfassend TBA, TEA, TEC und TBC, und/oder
• b) Carbonsäureester von Hydroxycarbonsäuren, insbesondere ein oder mehrere Ester ausgewählt aus der Reihe der Ester der Gluconsäure, der Isoascorbinsäure und/oder der Milchsäure und/oder
• c) Carbonsäureester ausgewählt aus der erfindungsgemäßen Verwendung,
• d) isoliert oder hergestellt sind und
• e) die Carbonsäureester oder Mischungen von Carbonsäureestern verbrannt werden und
• f) die dadurch freiwerdende Energie zum Heizen verwendet wird oder in einem geeigneten Speichermedium gespeichert wird.

The invention also provides a method for heating or for storing energy

• a) carboxylic acid esters of polybasic carboxylic acids, in particular one or more carboxylic acid esters selected from the series of carboxylic acid esters comprising TBA, TEA, TEC and TBC, and / or
• b) carboxylic acid esters of hydroxycarboxylic acids, in particular one or more esters selected from the series of the esters of gluconic acid, isoascorbic acid and / or lactic acid and / or
• c) carboxylic acid esters selected from the use according to the invention,
• d) are isolated or manufactured and
• e) the carboxylic acid esters or mixtures of carboxylic acid esters are burned, and
• f) the energy released thereby is used for heating or stored in a suitable storage medium.

• a) Carbonsäureester von mehrwertigen Carbonsäuren, insbesondere ein oder mehrere Carbonsäureester ausgewählt aus der Reihe der Carbonsäureester umfassend TBA, TEA, TEC und TBC, und/oder
• b) Carbonsäureester von Hydroxy-Carbonsäuren, insbesondere ein oder mehrere Ester ausgewählt aus der Reihe der Ester der Gluconsäure, der Isoascorbinsäure und/oder der Milchsäure und/oder
• c) Carbonsäureester ausgewählt aus der erfindungsgemäßen Verwendung,
• d) isoliert oder hergestellt sind und
• e) die Carbonsäureester oder Mischungen von Carbonsäureestern in einer Biobrennstoffzelle in elektrischen Strom umgewandelt werden und
• f) die dadurch freiwerdende Energie zum Antrieb eines Fahrzeugs oder zum Betrieb einer Maschine oder eines Gerätes verwendet werden kann.

The invention also provides a method for generating electric current

• a) carboxylic acid esters of polybasic carboxylic acids, in particular one or more carboxylic acid esters selected from the series of carboxylic acid esters comprising TBA, TEA, TEC and TBC, and / or
• b) carboxylic acid esters of hydroxy carboxylic acids, in particular one or more esters selected from the group of the esters of gluconic acid, isoascorbic acid and / or lactic acid and / or
• c) carboxylic acid esters selected from the use according to the invention,
• d) are isolated or manufactured and
• e) the carboxylic acid esters or mixtures of carboxylic acid esters in a biofuel cell are converted into electric current and
• f) the energy released thereby can be used to drive a vehicle or to operate a machine or a device.

Polyvalent carboxylic acids have at least two carboxylic acid groups (dicarboxylic acids). The invention relates to the use of esters of polybasic carboxylic acids, wherein the carboxylic acid is selected from the group of carboxylic acids comprising oxalic acid (ethanedioic acid), malonic acid (propanedioic acid), succinic acid (butanedioic acid), adipic acid (hexanedioic acid), pimelic acid (heptanedioic acid), suberic acid (octanedioic acid) , Azelaic acid (nonanedioic acid), sebacic acid (decanedioic acid), tartronic acid, tartaric acid, alpha-ketoglutaric acid, oxaloacetic acid, phthalic acid, isophthalic acid, terephthalic acid, glutamic acid, aspartic acid, citric acid, maleic acid, malic acid, fumaric acid, gluconic acid.

In a particularly preferred embodiment of the invention, the carboxylic acid has three carboxylic acid groups (tricarboxylic acids), such as citric acid or aconitic acid. In each case only one carbonyl group may be esterified in the di- or tricarboxylic acid or else two or three carbonyl groups. A mixture of fully and partially esterified carboxylic acids may also be used.

Citric acid is the common name for 2-hydroxypropane-1,2,3-tricarboxylic acid, d. H. Citric acid has three carboxylic acid functions and is saturated. Aconite acid is the common name for 1,2,3-propentricarboxylic acid, d. H. Aconite acid has three carboxylic acid functions and is unsaturated and therefore occurs in a cis and a trans form. In a preferred embodiment of the invention, esters of trans aconitic acid are used. In another preferred embodiment of the invention esters of cis-aconitic acid are used.

In a further particularly preferred embodiment of the invention, the polyvalent carboxylic acid has at least one double bond (unsaturated carboxylic acid), such as aconitic acid.

The invention relates to the use of esters of hydroxy carboxylic acids. Carboxylic acids are preferably used in which the hydroxy group is in the vicinity of the carbonyl group, preferably alpha-hydroxy carboxylic acids. The hydroxy carboxylic acids used may also be unsaturated.

Both the polybasic carboxylic acids and the hydroxy carboxylic acids all stereoisomers can be used (cis, trans, R, S).

It is a particular advantage of the present invention that the starting compounds can be obtained from renewable resources or waste.

For example, aconitic acid occurs in high concentrations in sugar cane. The recovery of trans aconitic acid from sugarcane is for example in Saska, M. et al. ((2006) International Sugar Journal, Vol 108, No. 1288, 203-209) described.

Alpha-hydroxy carboxylic acids (AHA) are also referred to as fruit acids, as they occur naturally in various fruits and other foods. Carboxylic acid esters based on alpha-hydroxy carboxylic acids can therefore also be obtained from renewable raw materials. Glycolic acid, for example, also from sugarcane juice.

It is a particular advantage of the invention that the carboxylic acid esters used according to the invention are formed during the fermentation. The carboxylic esters used are produced, for example, in biogas plants or can be easily produced in biogas plants.

The fuel can contain impurities and residues, especially impurities and residues that are created during the production process in biogas plants. Optionally, pure carboxylic acid esters or mixtures of carboxylic acid esters can be prepared and used.

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited non-patent literature

• Contion F., et al. ((2011) Energy Fuels, 25 (4), 1497-1503 [0005]
• Saska, M. et al. ((2006) International Sugar Journal, Vol 108, No. 1288, 203-209) [0032]

Claims (15)

Use of carboxylic acid esters as energy carrier, in particular as fuel or fuel, characterized in that the carboxylic acid ester is the ester of a polybasic carboxylic acid and / or the ester of a hydroxy carboxylic acid. Use according to one of the preceding claims, wherein the carboxylic acid is a di- or tricarboxylic acid and / or an alpha-hydroxy carboxylic acid. Use according to any of the preceding claims wherein the carboxylic acid is selected from the group of carboxylic acids including lactic acid, glycolic acid, gluconic acid, malic acid, tartaric acid, gallic acid, isocitric acid, citric acid, alpha-hydroxycaprylic acid, ascorbic acid, isoascorbic acid and aconitic acid. Use according to any one of the preceding claims wherein the carboxylic acid is selected from the group of polybasic carboxylic acids including oxalic, malonic, succinic, glutaric, adipic, pimelic, suberic, fumaric, maleic, phthalic, isophthalic, terephthalic, aconitic, citric, isocitric and tartaric acids , Use according to one of the preceding claims, wherein the carboxylic acid is esterified with one or more of the alcohols selected from the group of alcohols comprising methanol, ethanol, propanol, butanol, pentanol, hexanol, heptanol, octanol, nonanol, decanol and / or a polyhydric alcohol , Use according to any one of the preceding claims wherein the carboxylic acid ester is selected from the group of carboxylic acid esters comprising tributylaconitate (TBA), triethylaconitate (TEA), triethyl citrate (TEC) and tributyl citrate (TBC). Use according to any one of the preceding claims, wherein the energy carrier is a mixture comprising various carboxylic acid esters, preferably carboxylic acid esters of a di- or tricarboxylic acid and carboxylic esters of an alpha-hydroxy carboxylic acid and preferably at least one of the esterified carboxylic acids is an unsaturated carboxylic acid. Use according to one of the preceding claims, wherein the energy carrier comprises at least 70% by volume or 80% by volume of carboxylic acid ester, preferably at least 85% by volume or 90% by volume, particularly preferably at least 95% by volume or 97% by volume .-%. Use according to one of the preceding claims, wherein the operating material comprises not more than 10% by volume, preferably not more than 5% by volume, particularly preferably not more than 3% by volume of water. Use according to any one of the preceding claims, wherein the energy source comprises oxinates for reducing soot and improving the quality of the exhaust gas. Use of esters of polybasic carboxylic acids and / or esters of hydroxy-carboxylic acids, in particular selected from the use according to one of claims 1 to 10, for driving vehicles, for operating equipment and machines, for heating and for converting into storable forms of energy by means of suitable storage media. Use according to one of the preceding claims, wherein the use of the energy carrier is selected from the use as lamp oil. Method for driving a vehicle or a machine or a device wherein a) carboxylic acid esters of polybasic carboxylic acids, in particular one or more carboxylic acid esters selected from the series of carboxylic acid esters comprising TBA, TEA, TEC and TBC, and / or b) carboxylic acid esters of hydroxy carboxylic acids, in particular one or more esters selected from the group of the esters of gluconic acid, isoascorbic acid and / or lactic acid, and / or c) carboxylic acid esters selected from the use according to one of claims 1 to 10, d) are isolated or manufactured and e) the carboxylic acid esters or mixtures of carboxylic acid esters are burned in an internal combustion engine and f) the energy released thereby is used to drive a vehicle or to operate a machine or a device. A process for heating or storing energy wherein a) carboxylic acid esters of polybasic carboxylic acids, in particular one or more carboxylic acid esters selected from the series of carboxylic acid esters comprising TBA, TEA, TEC and TBC, and / or b) carboxylic acid esters of hydroxy carboxylic acids, in particular one or a plurality of esters selected from the group of esters of gluconic acid, isoascorbic acid and / or lactic acid, and / or c) carboxylic acid esters selected from the use according to any one of claims 1 to 10, d) are isolated or prepared and e) the carboxylic acid esters or mixtures be burned by carboxylic acid esters and e) the energy released thereby is used for heating or stored in a suitable storage medium. Method for generating electric current wherein a) carboxylic acid esters of polybasic carboxylic acids, in particular one or more carboxylic acid esters selected from the series of carboxylic acid esters comprising TBA, TEA, TEC and TBC, and / or b) carboxylic acid esters of hydroxy carboxylic acids, in particular one or more esters selected from the group of the esters of gluconic acid, isoascorbic acid and / or lactic acid and / or c) carboxylic acid esters selected from the use according to one of claims 1 to 10, d) are isolated or manufactured and e) the carboxylic acid esters or mixtures of carboxylic acid esters in a biofuel cell are converted into electric current and f) the energy released thereby can be used to drive a vehicle or to operate a machine or a device.