ITMI20121343A1 - USEFUL COMPOSITIONS AS FUELS INCLUDING GLYCERINE DERIVATIVES - Google Patents

Description

COMPOSITIONS USEFUL AS FUELS INCLUDING GLYCERINE DERIVATIVES

The present invention relates to a composition comprising a hydrocarbon mixture and one or more hydrophobic derivatives of glycerin. The above composition can be advantageously used as a fuel for diesel and petrol engines. The present invention also relates to the use of said hydrophobic derivatives of glycerin as a component for fuels.

It is known that the emissions produced by the combustion of fossil fuels containing carbon dioxide (CO2), carbon monoxide (CO), nitrogen oxides (NOx), sulfur oxides (SOx), unburnt hydrocarbons (HC), volatile organic matter and particulate matter (PM), are the cause of environmental problems such as, for example, the production of ozone, the greenhouse effect (in the case of nitrogen and carbon oxides), acid rain (in the case of sulfur oxides) and nitrogen).

In recent years, the increase in the cost of crude oil and a matured awareness of the environmental problems described above have strengthened the need to identify alternative, biodegradable and renewable energy sources.

Consequently, the progressive replacement of fuels deriving from fossil energy sources such as, for example, coal, oil, natural gas, with fuels deriving from alternative energy sources, such as, for example, vegetable oils, animal fats, biomass, algae, is becoming , worldwide, of increasing interest and efforts have therefore been made in the art in order to obtain new fuels from renewable energy sources.

An oxygenated compound, also obtainable from renewable sources, commonly added to fuels is ethanol, which however has the defect of being miscible with water, hygroscopic, and immiscible with diesel over a wide temperature range: yes it can therefore have phase separation and the mixtures obtained are unstable as described, for example, by Lapuerta and others in the article â € œStability of diesel-bioethanol blends for use in diesel enginesâ €, published in â € œFuelâ € (2007) , Vol. 86, pg. 1351-1357. Another alcohol, also obtainable from renewable sources, that can be used as a component to be added to fuels is butanol, which has a better miscibility with diesel than that of ethanol: however, it is still not satisfactory. In fact, at low temperatures, the butanol-diesel mixtures are not homogeneous. A further problem linked to the use of these alcohols is the low cetane number of the alcohol-diesel mixture which causes a high ignition delay in internal compression diesel engines.

It is also known the use of biodiesel and hydrotreated vegetable oils [â € œhydrotreated vegetable oilsâ € (HVO)] as they are, or mixed with diesel, as well as gas oil mixtures including alcohols of biological origin. Biodiesel generally comprises a mixture of alkyl esters of fatty acids, in particular a mixture of fatty acid methyl esters [â € œfatty acid methyl estersâ € (FAME)] and can be produced from raw materials of natural origin containing triglycerides ( generally triesters of glycerin with long alkyl chain fatty acids). Said raw materials as such, or the triglycerides obtained after having subjected said raw materials to separation, are subjected to a transesterification process in the presence of an alcohol, in particular methanol, and a catalyst, so as to obtain said esters alkyls of fatty acids, in particular called fatty acid methyl esters [â € œfatty acid methyl estersâ € (FAME)].

However, the use of said methyl esters of fatty acids (FAME) as they are, or in a mixture with gas oil, presents some problems with regard to the stability of oxidation and furthermore during the synthesis of FAME there is the formation, as a by-product, glycerin (about 10% by weight) whose use is an important aspect for the enhancement of the biodiesel production process.

It is also known the use of â € œhydrotreated vegetable oilsâ € (HVO), also called â € œgreen dieselâ €, which are produced by hydrogenation / deoxygenation of a material deriving from renewable sources such as, for example, soybean oil , rapeseed oil, corn oil, sunflower oil, including triglycerides and free fatty acids, in the presence of hydrogen and a catalyst as described, for example, by Holmgren J. and others in the article â € œNew developments in renewable fuels offer more choicesâ €, published in â € œHydrocarbon Processingâ €, September 2007, pg. 6771. This article highlights the best characteristics of these â € œhydrotreated vegetable oilsâ € (HVO), compared to the methyl esters of fatty acids (FAME), in particular, in terms of better oxidation stability and better properties cold. Furthermore, these â € œhydrotreated vegetable oilsâ € (HVO) do not present the problem of higher emissions of nitrogen oxides (NOx). However, due to the lack of oxygen atoms in these â € œhydrotreated vegetable oilsâ € (HVO), their use in diesel engines mixed with diesel in quantities of less than 5% by volume with respect to the total volume of said mixture, does not bring significant benefits regarding particulate emissions (PM).

The need is therefore felt to find new compositions useful as fuels in which there is a component deriving from renewable energy sources. The need is also felt to exploit glycerin, whose market is currently saturated, as a starting material to obtain compounds of biological origin that can provide high performance as fuel components. Currently one of the possible uses of glycerin is to make it react by means of an etherification reaction with olefins to give the corresponding ethers, useful as oxygenated components for petrol and diesel. The olefin used mainly and the subject of numerous patents is isobutene. The reaction with isobutene leads to the formation of tert-butyl ethers of glycerin, of which the most interesting is di-tert-butyl ether. In these ethers, however, the biological component is clearly minority since they consist of two, or rather three, molecule of isobutene per molecule of glycerin: consequently their contribution to the achievement of the share of biological origin is not sufficiently high. US2007 / 0283619 describes a process for the production of biofuels by transforming triglycerides into at least two families of biofuels containing monoesters of fatty acids and soluble ethers or acetals of glycerin. However, said ethers and acetals of the known art have a high affinity to water and low miscibility with the hydrocarbon phase: this is a serious limitation for their use as a component of fuels as not negligible quantities of water can be dissolved in the mixture of fuels that contains said acetals, with serious damage to the motor vehicle engine due to corrosion phenomena. Furthermore, the presence in gasoline of substances miscible with water leads to the formation of formaldehyde, a carcinogenic substance, in the emissions (B. Strus et al., Fuel 87 (2008), 957-963, ELSEVIER).

The Applicant has now found that the addition of particular hydrophobic derivatives from glycerin allows to obtain a composition which can be advantageously used as a fuel, in particular as a fuel for both diesel and gasoline engines.

Therefore, an object of the present invention are compositions useful as fuels, or as components of fuels, containing:

- at least one hydrocarbon mixture

- at least one compound of formula (I)

X- CH (Y) -CH2OR (I)

where is it

R is a C1-C8 alkyl, linear or branched

X is chosen between H and OCH (CH2OR) and Y is CH2OR

or

X and Y together correspond to the substituent = CH-OR.

Preferably R is selected from CH3, C2H5, C3H7, C4H9, C5H11. More preferably R can be selected from ethyl, n-propyl, iso-propyl, n-butyl, isobutyl, sec-butyl, tert-butyl, 3-methyl-1-butyl and 2-methyl-1-butyl. It is a particularly preferred aspect that R is ethyl or n-butyl.

The composition of the present invention can therefore contain one or more of the following glycerin derivatives, where R has the meanings described above:

RO-CH = CH-CH2-OR (Ia)

RO-CH2-CH2-CH2-OR (Ib)

(RO-CH2) 2CH-O-CH (CH2-OR) 2 (Ic)

The glycerin derivatives of formula (I) provide high performance as fuel components overcoming the problems of the known glycerine ethers concerning their high affinity with water and low affinity with the remaining hydrocarbon component of the fuel. The compounds of formula (I) have high characteristics such as octane number (or cetane), high calorific value, complete miscibility with the hydrocarbon phase and very low affinity with the aqueous phase, they are therefore not hygroscopic and therefore reduce the problems related to miscibility. and corrosion of engine parts due to the presence of traces of water. The compounds of formula (I), individually or in mixture with each other, can therefore be advantageously used as components for fuel, in particular diesel, especially for automotive use, and as additives for petrol, and their addition to diesel or petrol allows, among other things, to significantly reduce particulate emissions. The composition that contains them is less sensitive to the presence of water and consequently the corrosion phenomena in engines strongly decrease. Furthermore, the addition of the compounds of formula (I) has no negative influence on the characteristics of the starting gas oil such as, for example, the cold properties, the cloud point [â € œcloud pointâ € (CP)] and the point clogging of the filter [â € œcold filter plugging pointâ € (CFPP)], nor does it negatively affect the demulsibility characteristics and lubricating properties (â € œlubricityâ €) of the composition, nor does it negatively affect the stability to oxidation of the starting diesel.

In particular, the compounds of formula (Ic) are new and are a particular aspect of the present invention.

In accordance with a preferred embodiment of the present invention, said compounds of formula (I) can be present in said composition in quantities ranging from 0.5% by volume to 15% by volume, preferably between 1% by volume and 10% by volume, with respect to the total volume of said composition, where said quantities, when at least two compounds of formula (I) are present, refer to the sum of their volumes.

For the purpose of the present invention, any hydrocarbon mixture that can be used as a fuel can be used. In particular, the hydrocarbon blend can be chosen from diesel, petrol, biodiesel, green diesel, and their blends. In particular, said diesel oil can be chosen both among the diesel oils that fall within the specifications of the diesel fuel for motor vehicles according to the EN 590: 2009 standard, and among the diesel oils that do not fall within these specifications. Generally, diesel is a mixture containing hydrocarbons such as, for example, paraffins, aromatic hydrocarbons and naphthenes, typically having from 9 to 30 carbon atoms. Generally, the distillation temperature of gas oil is between 160 ° C and 450 ° C. In accordance with a preferred embodiment of the present invention, said gas oil can have a density, at 15 ° C, determined according to EN ISO 12185: 1996 / C1: 2001, between 780 kg / m <3> and 845 kg / m <3>, preferably between 800 kg / m <3> and 840 kg / m <3>. In accordance with a further preferred embodiment of the present invention, said gas oil can have a flash point, determined according to the EN ISO 2719: 2002 standard, greater than or equal to 55 ° C, preferably greater than or equal to 65 ° C. According to a preferred embodiment of the present invention, said gas oil can have a cetane number, determined according to the EN ISO 5165: 1998 standard, or the ASTM D6890: 2008 standard, greater than or equal to 47, preferably greater than or equal to 51.

Diesel oils that can be used well in the compositions of the present invention can therefore be all those known and can also derive from the mixing of diesel cuts of different origin and composition. Preferably the sulfur content of these diesel cuts is between 2000 and 50 mg / kg, and even more preferably between 50 and 3 mg / kg.

Typical diesel cuts can be middle distillates, preferably having a boiling point between 180 and 380 ° C. Examples of these cuts can be gas oils from primary distillation, gas oils from vacuum distillation, and from thermal or catalytic cracking, such as the desulfurized gas oil from catalytic fluid bed cracking (light cycle oil (LCO)), fuels from a Fischer-Topsch or synthetic origin process. Cuts obtained from these after hydrogenation treatment are also usable.

In the case in which the hydrocarbon mixture is a gasoline, the gasolines characterized by a T95 (ASTM D86) not higher than 250 ° C, preferably not higher than 240 ° C, where T95 means the temperature at which 95 distils % by volume of gasoline. Preferably, gasolines with T95 lower than 250 ° C, in particular lower than 240 ° C, having a density between 855 and 910 kg / m <3> are used. Well usable gasolines are those deriving from catalytic processes, preferably deriving from fluidized bed catalytic cracking (FCC) processes, from reforming processes, and their mixtures. In particular, therefore, HCN gasolines are used, i.e. heavy gasolines (initial boiling point 150 ° C) from FCC as such or desulphurized, and gasolines called Heavy reformate, i.e. heavy gasolines (initial boiling point 150 ° C) from reforming, or their blends.

Preferably the sulfur content of these petrol cuts is between 2000 and 50 mg / kg, and even more preferably between 50 and 1 mg / kg.

In the event that the composition contains a biodiesel called biodiesel, as previously mentioned, it will include a mixture of alkyl esters of fatty acids, in particular a mixture of fatty acid methyl esters [â € œfatty acid methyl estersâ € (FAME)] and can be produced starting from raw materials of natural origin containing triglycerides (generally triesters of glycerin with long alkyl chain fatty acids) such as, for example, crude vegetable oils obtained by pressing the seeds of oil plants such as, for example, rapeseed, palm, soy, sunflower, mustard, as well as from other sources of triglycerides such as, for example, algae, animal fats, or used or waste vegetable oils. Said raw materials as such, or the triglycerides obtained after having subjected said raw materials to separation, are subjected to a transesterification process in the presence of an alcohol, in particular methanol, and a catalyst, so as to obtain said esters alkyls of fatty acids, in particular called fatty acid methyl esters [â € œfatty acid methyl estersâ € (FAME)]. More details regarding biodiesel production are for example described in Hanna et al., In the review â € œ Biodiesel production: a reviewâ €, published in â € œBioresource Technologyâ € (1999), vol. 70, pp. 1-15. Preferably said biodiesel can be chosen among those that fall within the specifications of biodiesel for automotive according to the EN 14214: 2008 standards.

The composition may contain â € œhydrotreated vegetable oilsâ €, called â € œgreen dieselâ €,: they are produced by hydrogenation / deoxygenation of a material deriving from renewable sources such as, for example, soybean oil, rapeseed oil, corn oil, sunflower oil, including triglycerides and free fatty acids, in the presence of hydrogen and a catalyst as described, for example, by Holmgren J. and others in the article â € œNew developments in renewable fuels offer more choicesâ €, published in â € œHydrocarbon Processingâ €, September 2007, pg. 67-71.

The compositions of the present invention are prepared by mixing the individual components. Any other additives present in the final composition can be introduced both in the final composition itself and in the hydrocarbon mixture before their mixing.

The compounds of formula (I) are prepared starting from glycerin by means of a process in several stages, the first of which corresponds to the transformation of glycerin into 1,3-dialkoxy-2-propanol of formula (Ix):

RO-CH2-CHOH-CH2-OR (Ix)

Said etherification step can be carried out according to any of the known methods for the preparation of ethers. For example, glycerin can be reacted in the presence of alcohol and an acid catalyst. Well usable acid catalysts are, for example, acid exchange resins, acid zeolites, silico aluminas, supported phosphoric acid. Well usable solvents are preferably the same alcohols with which the corresponding ether is to be formed. Preferably the reaction is carried out at a temperature comprised between 50 and 200 ° C, and at a pressure comprised between 1 and 20 atmospheres. The space velocity is preferably between 0.1 and 20 hours <-1>. The molar alcohol / glycerin ratio is preferably between 2 and 10.

ROH alcohols which can be used well to prepare the alkoxides of step (1) are alcohols in which R is a linear or branched alkyl containing from 1 to 8 carbon atoms, preferably from 2 to 5 carbon atoms. Well usable alcohols are therefore ethanol, isopropanol, n-propanol, n-butanol, iso-butanol, secbutanol, tert-butanol, 3-methyl-1-butanol, 2-methyl-1-butanol. Ethanol or nbutanol are preferred.

Preferably, alcohols will be used that are also obtainable biologically, i.e., for example, obtainable by fermentation of biomass or biomass derivatives, or by fermentation of biomass deriving from agricultural crops rich in carbohydrates and sugars, or by fermentation of biomass lignocellulosic, or by fermentation of algal biomass. Ligninocellulosic biomass can derive from agricultural crops rich in carbohydrates and sugars such as, for example, corn, sorghum, barley, beet, sugar cane, or their mixtures. For example, the lignocellulosic biomass can be chosen from:

- products of crops specifically cultivated for energy use (such as, for example, miscanthus, panic, rods, common reeds), including waste, residues and waste from these crops or their processing;

- products of agricultural crops, forestry and forestry, including wood, plants, residues and waste from agricultural processing, forestry and forestry;

- waste from agro-food products intended for human consumption or zootechnics;

- the residues, not chemically treated, from the paper industry;

- waste from the separate collection of solid urban waste (such as, for example, urban waste of vegetable origin, paper, etc.);

or their mixtures.

The alcohol used can, for example, also derive from the fermentation of at least one algal biomass grown for energy purposes, or by fermentation of residues or derived from the cultivation of said biomass.

Fermentation can be carried out in accordance with methods known in the art. For example, said fermentation can be carried out in the presence of natural microorganisms, or genetically modified microorganisms in order to improve said fermentation. Any of the known methods of obtaining ethanol from biomass is suitable for providing ethanol usable in the present invention. Production processes of ethanol from biomass are for example described in US 5562777; US 2008/0044877; â € œ Ethanol from ligninocellulosic biomass: technology, economics and process for the production of ethanolâ € F. Magalhaes, R.M. Vila Cha-Baptista, 4 <th> International Conference on Hands-on Science Development, Diversity and Inclusion in Science Education 2007; â € œ Ethanol fermentation from biomass resources: current state and prospectsâ € Y. Lin, S.Tanaka, Appl. Microbiol. Biotechnol. (2006) 69: 627-642; â € œHydrolysis of ligninocellulosic materials for ethanol production: a reviewâ € Y. Sun, J. Cheng, Bioresource Tecnology, volume 83, Issue 1, May 2002, pages 1-11.

It is another aspect of the present invention to use propanol, preferably iso-propanol, as the alkylating agent. According to a preferred aspect, in accordance with what is reported above in general for bio-alcohols, propanol of biological origin is used, preferably obtained by fermentation of biomass, as described for example in US2009 / 0246842.

It is another aspect of the present invention to use butanol, preferably n-butanol, as the alkylating agent, in accordance with what is reported above in general for bio-alcohols. According to a preferred aspect, biobutanol is used, i.e. butanol of bio origin, preferably prepared by fermentation of biomass, according to the A.B.E. (acetone / butanol / ethanol). The A.B.E. uses the bacterium Clostridium acetobutylicum and was first described in US 1315585. From this process acetone, butanol and ethanol are obtained which can then be separated by subsequent distillations. Changes and improvements of the A.B.E. process they are described for example in US 5753474, US 5192673, and in Chang-Ho Park, Biothecnol.Bioprocess Eng. 1996, 1, 1-8.

The 1,3-dialkoxy-2-propanol (Ix) is then subjected to dehydration to obtain the compound of formula (Ia), 1,3-dialkoxy-propene: the dehydration is carried out in the presence of a suitable catalyst, according to one any of the known methods for dehydrating compounds containing hydroxyl groups. For example, the catalyst can be chosen from silica, silica-alumina, zeolites, acid exchange resins, acid clays, heteropolyacids supported on silica or activated carbon. High boiling linear alkanes, for example hexadecane, can be well used as solvents. The dehydration reaction can be carried out at a temperature between 150 ° C and 350 ° C, at a pressure between 0 and 2 atmospheres.

More details relating to dehydration processes usable in the preparation process of the present invention are described, for example, in K. Mori, Y. Yamada, S. Sato, Appl. Catal. A, 336, 2009, 304-8.

By operating under milder dehydration conditions than those described above by 1,3-dialkoxy-2-propanol (Ix), the compound of formula (Ic), 2,2â € ™ -oxybis (1,3-dialkoxypropane) is obtained,: in particular, one operates at a temperature between 100 and 200 ° C, and at a pressure between 3 and 20 atmospheres. Catalysts and solvents are the same as reported above for the dehydration of (Ix) to give the compound (Ia).

The compound of formula (Ib), 1,3-dialkoxy-propane can be obtained from 1,3-dialkoxy-propene (Ia) by hydrogenation: said hydrogenation is carried out with hydrogen in the presence of a suitable catalyst, according to any of the methods known for the hydrogenation of double bonds. For example, it is possible to react 1,3-dialkoxy-propene with hydrogen in the presence of a hydrogenation catalyst; all the hydrogenation catalysts known to the expert can be used, and for example the catalyst can be chosen from platinum on carbon, platinum on alumina, palladium on carbon, metal VIII supported group.

High boiling aliphatic hydrocarbons, for example hexadecane or octadecane, can be well used as solvents. The hydrogenation reaction can be carried out at a temperature between 25 ° C and 250 ° C, under hydrogen pressure between 1 and 80 atmospheres,

The fuel composition object of the present invention may possibly include conventional additives known in the art such as, for example, â € œflow improversâ €, â € œlubricity improversâ €, â € œcetane improversâ €, antifoam, detergents, antioxidants, anticorrosives, additives antistatic agents, dyes, or mixtures thereof. Generally, if present, said additives are present in quantities not exceeding 0.3% by volume with respect to the total volume of said composition taken equal to 100.

In order to better understand the present invention and to put it into practice, some illustrative and non-limiting examples thereof are reported below.

EXAMPLE 1 - Synthesis of 1,3-diethoxy-2-propanol (Ix, with R = CH2CH3)

A catalyst consisting of a commercial acid resin (Amberlyst 36) is charged into a fixed bed reactor heated to a temperature of 180 ° C and a mixture of glycerin and ethanol in a molar ratio 1/10 is fed, at a temperature of 180 °. C and at the space velocity of 0.5 hours <-1>. A conversion of glycerin equal to 85% is obtained with a selectivity to 1,3-diethoxy-2-propanol of 20%.

The diethoxypropanediol thus obtained from the monoethoxy-propanediol and the unreacted glycerin is separated by distillation.

EXAMPLE 2 - Synthesis of 1,3-diethoxy-propene (Ia, with R = CH2CH3)

In a fixed bed reactor, filled with zeolite Y in acid form with a molar ratio of SiO2 / Al2O3 equal to 10, previously heated to 180 ° C, a flow of 1.3 diethoxy- 2 propanol obtained in example 1. The samples are collected at regular time intervals and analyzed by gas chromatography. A conversion of 1,3-diethoxy-2-propanol equal to 90% is obtained, with a selectivity to the desired product equal to 95%.

EXAMPLE 3 - Synthesis of 2,2â € ™ -oxy-bis (1,3-diethoxypropane) (Ic, with R = CH2CH3) 50 g of 1,3-diethoxy-propene (Ia ), prepared as described in the previous example and add 4 g of Amberlyst 36 acid exchange resin. The autoclave is closed and heated to 130 ° C, stirring for 3 hours. At the end of this period the autoclave is cooled down to room temperature and, after having opened it, the reaction products are analyzed. A conversion of 80% of the 1,3-diethoxy-propene initially present is determined with a selectivity to 2,2â € ™ -oxy-bis (1,3-diethoxypropane) equal to 85%, with the complement to 100 consisting of mono -ethoxy-propanediol and 1,2,3 triethoxy-propane.

The desired product 2,2â € ™ -oxy-bis (1,3-diethoxypropane) is easily separated from the reaction mixture by distillation.

Claims (9)

CLAIMS 1) Composition containing: - at least one hydrocarbon mixture - at least one compound of formula (I) X- CH (Y) -CH2OR (I) where is it R is a C1-C8 alkyl, linear or branched X is chosen between H and OCH (CH2OR) and Y is CH2OR or X and Y together correspond to the substituent = CH-OR. 2) Composition according to claim 1 containing one or more of the following compounds (I): RO-CH = CH-CH2-OR (Ia) RO-CH2-CH2-CH2-OR (Ib) (RO-CH2) 2CH-O-CH (CH2-OR) 2 (Ic) where R is a C1-C8 alkyl, linear or branched. 3) Composition according to claim 1 or 2 wherein in the compounds of formula (I) R is selected from CH3, C2H5, C3H7, C4H9, C5H11. 4) Composition according to claim 3 wherein R is selected from ethyl, npropyl, iso-propyl, n-butyl, isobutyl, sec-butyl, tert-butyl, 3-methyl-1-butyl and 2-methyl- 1-butyl. 5) Composition according to claim 4 wherein R is ethyl or n-butyl. 6) Composition according to claim 1 wherein the compound of formula (I) or the compounds of formula (I) are present in an amount comprised between 0.5% by volume and 15% by volume, with respect to the total volume of the composition. 7) Composition according to claim 6 wherein the compound of formula (I) or the compounds of formula (I) are present in an amount comprised between 1% by volume and 10% by volume, with respect to the total volume of said composition . 8) Composition according to claim 1 in which the hydrocarbon blend is chosen from diesel, petrol, biodiesel, green diesel, and their blends. 9) Use of the composition according to claim 1 as fuel or fuel component 10) Use as a fuel component of compounds of formula (I) X- CH (Y) -CH2OR (I) where is it R is a C1-C8 alkyl, linear or branched X is chosen between H and OCH (CH2OR) and Y is CH2OR or X and Y together correspond to the substituent = CH-OR. 11) Use in accordance with claim 9 or 10 in which the fuel contains a hydrocarbon mixture chosen from diesel, petrol, biodiesel, green diesel and their blends. 12) Compound of formula (Ic): (RO-CH2) 2CH-O-CH (CH2-OR) 2 (Ic) where R is a C1-C8 alkyl, linear or branched.