BR102012033512B1 - USE OF 2H-HOLE DERIVED MOLECULES [3,2-B] BENZOPIRAN-2-ONAS, FLUORESCENT, AS FUEL MARKERS FOR ADULTERATION DETECTION - Google Patents

Abstract

application of molecules derived from 2h-bore [3,2-b] benzopyran-2-ones, fluorescent, as fuel markers for identification of adulteration. the following work consists of the summary for the presentation of the patent proposal for fluorescent markers in automotive liquid fuels (gasoline, diesel oil and alcohol) using the fluorescence spectrophotometry technique. fuel marking in brazil is applied for product customization, such as identification of the manufacturer or supplier (distributor, flag); as well, in order to identify adulteration of these - a problem that still affects the whole country and brings many economic losses, both for the consumer and for the union. currently, the methodology officially applied by the national oil, natural gas and biofuels agency (anp - resolution anp no. 13, of June 9, 2009; resolution anp no. 3, of January 19, 2011) for the identification of gasoline adulteration uses the gas chromatography technique for analysis of markers that, if present in it, verifies adulteration through the use of marked solvents. this methodology presents some unfavorable aspects, such as the heavy logistics for collecting samples and the use of gas chromatography, which is an expensive, slow technique, requiring highly trained technicians and specialized laboratories and identifies only some types of adulteration. the proposed technique for identifying fuel adulteration, fluorescence spectrophotometry with new fluorescent molecules, has the advantages of being cheaper, more robust and able to identify any type of adulteration and be carried out at the sampling site. Keywords: liquid fuel, marker, adulteration, analysis

Description

USE OF 2H-HOLE DERIVED MOLECULES [3,2-B] BENZOPIRAN-2-ONAS, FLUORESCENT, AS FUEL MARKERS FOR ADULTERATION DETECTION Field of the Invention

The present invention deals with the use of polyaromatic molecules, derived from 2H-bore [3,2-b] benzopyran-2-ones (Figure 1), containing a furan-derived ring and with substituents (eg, phenyl and halogens), in marking of liquid fuels and petroleum-based solvents, detection of possible adulteration of these fuels, using the fluorescence spectrophotometry technique to detect these molecules.

More specifically, in the use of molecules derived from 2H-bore [3,2-b] benzopyran-2-ones as markers of gasoline, diesel oil (with or without biodiesel) and hydrated ethyl alcohol, used as automotive fuels, and in the identification of adulteration of these fuels, using the fluorescence spectrophotometry technique to detect these molecules.

The present invention relates to a method for preparing and detecting markers for automotive fuels and petroleum-based solvents, using these fluorescent organic compounds, never used as this type of marker, which, when added to the fuel or solvent sample used as adulterants, they can be detected using a fluorescence spectrophotometric method. The marker, pure or in solution, is added to the fuel or petrochemical solvent in sufficient quantity to correspond to a final concentration in the order of ppm, as normally recommended by the National Agency of Petroleum, Natural Gas and Biofuels (ANP).

• I- Desenvolvimento do método analítico espectrofluorimétrico para detecção e quantificação destes marcadores nos combustíveis.
• II- Avaliação da intensidade da fluorescênciados respectivos marcadores nos combustíveis (álcool etílico hidratado, gasolina e óleo diesel) através das curvas analíticas;
• III- Avaliação da intensidade da fluorescência dos respectivos marcadores nos combustíveis (álcool etílico hidratado, gasolina e óleo diesel), através das curvas analíticas,após a adulteração deste combustíveis.

In this sense, the present invention encompasses the following steps:

• I- Development of the analytical spectrofluorimetric method for detecting and quantifying these markers in fuels.
• II- Evaluation of the fluorescence intensity of the respective markers in the fuels (hydrated ethyl alcohol, gasoline and diesel oil) through the analytical curves;
• III- Evaluation of the fluorescence intensity of the respective markers in the fuels (hydrated ethyl alcohol, gasoline and diesel oil), through the analytical curves, after the adulteration of these fuels.

The methodology used took into account the requirements of the application of the molecular fluorescence spectrophotometry technique, in order to determine the specific absorption and emission wavelengths (λ) for each marker.

Fundamentals of the Invention

In Brazil, adulteration of fuels is a very recurrent and relevant problem, generating losses not only for the consumer, in terms of engine performance and damage, but also for the environment (due to the increase in pollutant emissions, as a result of reduction of fuel quality) and for the country, in terms of tax collection evasion, due to adulteration by the addition of solvents with less tax impact, damaging the collection by governments. Monitoring of fuel quality is carried out by the ANP, which has been operating, since 2002, in the inspection and monitoring of fuels in Brazil, where periodic samplings are carried out at gas stations throughout the country, stratified in each state, by defined regions, and the samples are taken to accredited laboratories for analysis, requiring a very complex and expensive logistics structure and transportation.

Officially, markers are used to identify “flags” of fuel distributors and markers in solvents to enable the characterization of adulteration of fuels, generally identifiable by the chromatography technique (ANP). In this invention, we apply molecules derived from 2H-bore [3,2-b] benzopyran-2-ones, with phenyl and halogen substituents, in the marking of liquid fuels and solvents, for the detection of possible adulteration of these fuels, using the fluorescence spectrophotometry technique.

Related technique

Several types of markers have already been developed for hydrocarbons, including benzaldehydes (Use of Benzaldehydes to Mark hydrocarbons BG101156 (A) 1997-08-29), aromatic 'beta' dicarbonyl or orthohydroxycarbonyl, leucotriarylmethanes (Use of Leucotriarylmethanes for marking hydrocarbons MX9700119 (A) 1997-04-30; MX9700116 (A) 1998-01-31), free and complexed phthalocyanines and naphthalocyanines, composed of aromatic amines and acid pigments (US Patent No. 5,525,516; Method for tagging petroleum products, 1996), derivatives of morpholino (YU181180 (A) 1985), etc.

There are several techniques applied to identify the marking of petroleum products and fuels. Next, the main techniques and markers and the respective considerations will be presented.

Various forms of marking fuel and oil are carried out by color development. Rhodamine B is used in the development of color on silica to detect adulteration in gasolines, Method for determining adulteration of gasolines US5358873 (A) 1994-10-25. As well as, the use of two agents, as in the Method for the marking of mineral oil patent US2004110302 (A1), 06/10/2004 and in the patent Marker for petroleum products and Method for marking and detecting petroleum products KR20020033033 (A) 2002- 05-04, using a bisphenylisobenzofuranone derivative and a tetraalkylammonium derivative. In other cases, color is developed through acid or basic extraction: Method for detecting acid- and base-extractable markers EP0887644 (A1) 1998-12-30. A not very common way is the marking by adding a soluble and low evaporation marker that will be detected in the gasoline evaporation residue, as in the patent Tagging materials for gasoline US5512066 (A) 1996-04-30. Solid phase extraction techniques are also used, with formation of a colored complex to detect gasoline adulteration, US19890326720; as well as extraction in liquid phase, with chromophoric reaction for marking petroleum fuels, patent Process for preparing a solution of water immiscible solvent, petroleum fuel marked with a compound and process for marking an oil fuel PI9701916-0 B1 , 04/23/1997.

UV / Vis spectrophotometry is also a technique widely used to identify the marking of oil and fuels, represented by the patents here: Method for marking liquid hydrocarbons CN1504739 (A) 2004-06-16, anthraquinone, as a marker; pyrazinoporphyrazine compounds with maximum absorption of 700 nm and 900 nm KR20040007273 (A) 2004-01-24; Dicetone-derived marker for petroleum-based fuels and combustible alcohols PI0803126-6 A2, 07/08/2008; diketones as fuels, Chemical tracer for marking liquid automotive fuels and tracer quantification method PI0801672-0, 06/04/2008; Automotive gasoline marker and method of preparation, detection and quantification of automotive gasoline marker PI0702092-9, 03/29/2007.

The technique of spectrophotometry in the infrared region is also applied for the detection of petroleum derivatives marking. The Method and Apparatus for marking and identifying liquids patents KR20010020591, 2001-03-15; System for detection of adulterated fuel by optical to capacitive method and equipment PI0800351-3 A2, 10/03/2008; Process for marking liquid hydrocarbon, marker composition for identifying liquid hydrocarbon, process to assist in the identification of said liquid, as well as apparatus to assist in that identification PI9810639-2 B1 06/30/1998, present a system with two agents, for analysis of fuel marking, using the ratio of the concentrations of these markers. Phthalocyanines and free and complex naphthalocyanines, composed of aromatic amines and pigments absorb in the region between 600 and 1200nm (US Patent No. 5,723,338; Tagging hydrocarbons for subsequent identification, 1998; US Patent No.5,843,783; Tagging hydrocarbons for subsequent identification, 1998) and can be identified by spectroscopy in the infrared region (US Patent No.6.340.745. Metallic phthalocyanines (IA), metallized (de) naphthalocyanines (IB), Nidithiolene complexes (IC), CPDS aminium. (ID) of aromatic amines, methin dyes (IE) or azulene-aquaric acid dyes (IF), patent Use of compounds which absorb and / or fluoresce in the IR region as markers for liquids ZA9305300 (A) 199501-23, are useful to distinguish fuel oil from diesel oil with very strong absorption in the infrared region, to allow detection with standard photometers.

The mass spectrometry technique is also present among the techniques applied in the identification of gasoline adulteration, coupled with the chromatography technique; but also directly in the identification of solvent marking. Examples of patents: Process for the identification of gasolines adulterated by solvents for the detection of chemical markers by mass spectrometry with atmospheric pressure ionization PI0503345-4 10/05/2005 e A sensitive and selective sensor for the “In situ” detection of adulteration of gasoline with solvents PI0307653-9 A2 28/01/2003.

Other alternative techniques that use several physical-chemical and other properties, such as impedance, radiofrequency, density and specific mass, NMR (Nuclear Magnetic Resonance), electrical conductivity, etc., for the identification of petroleum derivatives marking appear in patents such as: PI0703564- 0 A2; PI0204519-2; MU8200991-0; PI0605247-9; PI0105205-5 A2; PI0800351-3 A2, respectively. Another form that is not very common is the formation of polymers (polymerization) Polymerizable dyes as taggants US6007744 (A).

Fluorescent markers for various liquids, phthalocyanine, naphthalocyanine, nickel-dithiolene complexes, amino compounds of aromatic amines, metinoazulene dyes, metinoazulenoesquaric and cyanine acid dyes, are presented, respectively, in the patents NO20003811 (A), US5998211 (A), US5808247 (A) ), ZA9508247 (A), 1996-04-24 and PI0005843-2 A2. The fluorescence of the markers in liquids can be stimulated by means of a semiconductor laser or a semiconductor diode, as they have a maximum emission wavelength in the gamma region (US Patent No. 5,998,211; Use of compounds which absorb and / or fluoresce in the IR region as markers for liquids, 1999).

There are patents already registered using fluorescence to indicate the marking of petroleum or fuel US5879946 (A). JP2009507782 (A) discloses ester groups, with double bond, in the marking of petroleum derivatives; however, it needs a second agent for the development of fluorescence, as also occurs in the patent GR3034049 (T3). Phosphines or fluorescent porphyrin derivatives also appear as gasoline or mineral oil markers, patent GB2354070 (A). An interesting case is that of a marker that can be detected by measuring the fluorescence generated from the selective ester hydrolysis, by action enzyme, US2004092738 (A1) patent.

However, some considerations must be made in relation to the various methodologies presented for the identification of tampering. The main markers and methods using UV-Visible molecular absorption spectrophotometry, generally require an extraction step with an organic solvent or even by chemical reaction with inorganic compounds. Often, the solvent used in the extraction has high toxicity (US Patent No. 5,755,832, Fuel additive concentrate containing tagging material, 1998; US Patent No. 6,482,651, Aromatic esters for marking or tagging petroleum products, 2002), in addition to require a lot of manipulation on the part of the technical analyst.

Some organic markers containing groups of hydroxiftaleins, such as phenolphthalein, for example, had the use proposed in 1994, as a fuel marker by the North American Environmental Protection Agency; however, the attempt was unsuccessful due to the fact that phenolphthalein has inadequate solubility in petroleum products, leading to partial crystallization in the fuel and because it is particularly sensitive to alkalinity, which makes it difficult to extract petroleum fuels. Thymolphthalein and cresolphthalein have also been proposed as markers, by adding fuels in a preferred range of 0.5 to 100 ppm (U.S. Patent No. 6,002,056; Colorsless petroleum markers, 1999) and a reagent to promote color development; however, for the quantification of this marker, molecular absorption spectrophotometry is used in the visible region, which requires a certain amount of time, due to the necessary pre-treatment, in addition to the marker presenting toxicity to the human organism.

Radioactive substances and a variety of slightly colored or colorless markers are also found, which require selective reagents to produce intensely colored derivatives. Radioactive markers, (US Patent No. 3,682,187; US Patent No. 3,687,148; US Patent No. 6,808,542, Photoluminescent markers and methods for detection of such markers, 2004; US Patent No. 6,312,958, Method for marking liquids with at least two marker substances and method for detecting them, 2001, EP 1,191,084, Colorless petroleum marker dyes, 2002), in particular, have not been well accepted due to the need to work with special equipment and handling preventive, to avoid occurrences of human physiological disorders.

There are also proposals to use more than one marker simultaneously in gasoline. In this case, the molecular mass distributions of the markers must not be superimposed, each of them must be present in concentrations below 1 ppm in the fuel, and must not vaporize or decompose at temperatures below 120 ° C. As an example, we have the copolymers (U.S. Patents No. 3,682,187 and No. 3,687,148) of high molecular weight.

The need to use a chromatograph or other separation device makes the procedure difficult, due to the cost of the analytical technique and the time dedicated to it (US Patent No. 5,710,046; Tagging hydrocarbons for subsequent identification, 1998). Another major problem is related to the fact that the absorption scale of one marker overlaps that of the other marker.

Phenylazophenols (U.S. Patent No. 5,156,653; Silent markers for petroleum, method of tagging, and method of detection, 1992) can be detected after extraction using a strong alkaline solution. The color developed by the markers is unstable and not very intense, reducing the possibility of good quantitative determinations with simple field equipment, making the use of sophisticated equipment mandatory.

Amine markers for gasoline, consisting of nitrogenous compounds (Polysobutylamine, Poly (oxyalkylene) aminocarbamate, Polybutenesuccinimide), called concentrated additives, in addition to the need for a solvent, at least they need another substance with a sufficient marker function so that detected (US Patent No.5,755,832; Fuel additive concentrate containing tagging material, 1998). The naphthylamine marker selected consists of (naphthylamino) - (naphthylamino) -propane 1- (4-morpholino) -3-alpha and (naphthylamino) - (naphthylamino) -propane 1- (4-morpholino) -3-beta.

In other cases, to detect trademark violations, the marker manufacturer recommends a typical concentration level of around 20 ppm. However, the costs of the marker and reagents for these concentration levels are relatively expensive and can be prohibitive for many applications (U.S. Patent No.5,229,298; Method of analyzing marker dye concentrations in liquids, 1993).

Diazo markers, another example of markers used in petroleum products (US Patent No.4,049,393; Colored Petroleum-Derived Product, 1977), present the difficulty of extracting them from the matrix for later quantification and identification (US Patent N ° 3,862,120; Disazo Dye Resistant to Adsorption, 1972).

Furfural, quinizarin and diphenylamine (U.S. Patent No. 4,735,631, Colored petroleum markers, 1988; Kalligeros, S. et al; Fuel adulteration Issues in Greece, 2003) are examples of widely used markers. However, these have not been accepted in Western countries as they require special equipment and precautionary measures associated with their control for use in fuels. Quinizarin and diphenylamine are very sensitive markers, with simple detection procedures, but they have the disadvantage of low solubility in nonpolar solvents.

• a - requer pessoal técnico bastante especializado, pois a técnica exige bastante capacitação; como também, os equipamentos e insumos são bastante caros, além da análise demandar um tempo relativamente grande e geralmente ser realizada apenas em laboratórios especializados;
• b - grande dificuldade de ser aplicada em campo;
• c - a metodologia identifica apenas alguns tipos de solventes que também são empregados comumente como adulterantes e por isso são marcados para possibilitar a identificação da adulteração.

Currently, the methodology officially applied in Brazil by the National Agency of Petroleum, Natural Gas and Biofuels (ANP - Resolution ANP No. 13, of June 9, 2009; Resolution ANP No. 3, of January 19, 2011) for the identification of adulteration of gasoline uses the gas chromatography technique for analysis of markers which, if present in it, verifies adulteration through the use of marked solvents. Chromatography is also applied in US Patent No. 5,229,298 Method of analyzing marker dye concentrations in liquids, \ 993 and Phthalocyanine and use of phthalocyanine as a marking agent, 2002. This methodology has some unfavorable aspects:

• a - requires highly specialized technical personnel, as the technique requires a lot of training; as well, equipment and supplies are quite expensive, in addition to the analysis taking a relatively long time and generally being carried out only in specialized laboratories;
• b - great difficulty to be applied in the field;
• c - the methodology identifies only some types of solvents that are also commonly used as adulterants and therefore are marked to enable the identification of adulteration.

As seen, the official identification of the fuel adulterant in Brazil presents difficulties due to the technique used and the restrictive application due to the fact that only a few solvents are marked and possible to be identified.

Summary of the invention

The fluorescent organic molecules derived from the 2H-hole [3,2-b] benzopyran-2-ones, from substituted polyaromatic rings, synthesized in a simple process that uses water as a solvent, can be used directly in fuels, or added in the form of solutions, in ppm or ppb concentrations, as markers for quick detection of adulteration of fuels in loco, through the analytical technique of fluorescence spectrophotometry. In addition, it allows the custody of fuel samples for a long period for later reanalysis, due to the great stability of these additives (markers).

These polyaromatic molecules, synthesized in the laboratory of the Department of Organic Chemistry of the Institute of Chemistry at the Federal University of Bahia, have a high degree of fluorescence. Thus, they were applied in the preparation of analytical curves relating the concentrations and their respective fluorescences in gasoline, diesel oil and fuel alcohol, as matrices. It was found that samples of the fuels marked by these molecules, and which were later adulterated, had different fluorescence intensity than the original marked samples.

Brief description of the Figures

Figure 1 shows the general structure of molecules derived from 2H-bore [3,2-b] benzopyran-2-ones. Figure 2 shows the analytical curve of the marker 1-bromo-2-iodo-2H-hole [3,2- b] benzopyran-2-one in alcohol, relating the concentration and intensity of fluorescence. Figure 3 shows the analytical curve of the marker 1-bromo-2H-hole [3,2- b] benzopyran-2-one in gasoline, relating the concentration and intensity of fluorescence. Figure 4 shows the analytical curve of the marker 1-phenyl-2H-hole [3,2- b] benzopyran-2-one in diesel, relating the concentration and intensity of fluorescence.
Figure 5 shows the analytical curve of the adulteration of the labeled alcohol (with 1 ppm of 1-bromo-2-iodo-2H-hole [3,2- b] benzopyran-2-one), relating% of adulteration with water and intensity fluorescence; Figure 6 shows the adulteration analytical curve to obtain the Detection Limit (LD). Figure 7 shows the analytical curve of the adulteration of the labeled alcohol (with 1 ppm of 1-bromo-2-iodo-2H-hole [3,2- b] benzopyran-2-one), relating% of adulteration with methanol and intensity fluorescence; Figure 8 shows the adulteration analytical curve to obtain the Detection Limit (LD).
Figure 9 shows the analytical curve of adulteration of marked gasoline (with 1 ppm of 1-bromo-2H-bore [3,2- b] benzopyran-2-one), relating% of adulteration with toluene and fluorescence intensity; Figure 10 shows the adulteration analytical curve to obtain the Detection Limit (LD). Figure 11 shows the analytical curve of adulteration of marked gasoline (with 1 ppm of 1-bromo-2H-bore [3,2- b] benzopyran-2-one), relating% of adulteration with diesel and fluorescence intensity; Figure 12 shows the adulteration analytical curve to obtain the Detection Limit (LD). Figure 13 shows the analytical curve of adulteration of marked gasoline (with 1 ppm of 1-bromo-2H-bore [3,2- b] benzopyran-2-one), relating% of adulteration to turpentine and fluorescence intensity; Figure 14 shows the adulteration analytical curve to obtain the Detection Limit (LD). Figure 15 shows the analytical curve of adulteration of marked gasoline (with 1 ppm of 1-bromo-2H-bore [3,2- b] benzopyran-2-one), relating% of adulteration with kerosene and fluorescence intensity and, also, to obtain the Detection Limit (LD).
Figure 16 shows the analytical curve of the adulteration of the marked diesel (with 1 ppm of 1-phenyl-2H-bore [3,2- b] benzopyran-2-one), relating% of adulteration with kerosene and fluorescence intensity; Figure 17 shows the analytical curve of adulteration to obtain the Limit of Detection (LD). Figure 18 shows the analytical curve of the adulteration of the marked diesel (with 1 ppm of 1-phenyl-2H-bore [3,2-b] benzopyran-2-one), relating% of adulteration with turpentine and fluorescence intensity; Figure 19 shows the adulteration analytical curve to obtain the Detection Limit (LD). Figure 20 shows the analytical curve of the adulteration of the marked diesel (with 1 ppm of 1-phenyl-2H-bore [3,2- b] benzopyran-2-one), relating% of adulteration with residual cooking oil and intensity of fluorescence; Figure 21 shows the analytical curve of adulteration to obtain the Limit of Detection (LD).

Detailed description of the invention

Molecules derived from 2H-bore [3,2-b] benzopyran-2-ones, from polyaromatic rings with halogen, phenyl (and / or substituted phenyl) substituents, are added directly (or solubilized) to fuels, in ppm levels or ppb. It was decided to solubilize the markers in some solvents, which are not used as adulterants, before adding them to the fuels, for a greater guarantee of solubility, homogeneity and stability of the markers in the respective fuels. In addition, the concentration of 1 ppm of the marker in each fuel was considered. After several tests with possible markers, and solvents, with the respective fuels, the most efficient results follow.

• I- para o álcool etílico, adicionou-se ao combustível um volume de solução de1-bromo-2-iodo-2H-furo[3,2- b]benzopiran-2-onaem acetato de etila, de modo que o volume da solução do marcador atingiu apenas cerca de 0,15%, do volume final, e o marcador com concentração final de 1 ppm no combustível; Figura 2 apresenta a curva analítica, relacionando concentração e intensidade de fluorescência, com comprimentos de onda de excitação (λex) em 356 nm e emissão (λem) em 426 nm.
• II- Para a gasolina, adicionou-se ao combustível um volume de solução de 1-bromo-2H-furo[3,2-b]benzopiran-2-ona em acetato de etila, de modo que o volume da solução do marcador atingiu apenas cerca de 0,15%, do volume final, e o marcador com concentração final de 1 ppm no combustível; Figura 3 apresenta a curva analítica, relacionando concentração e intensidade defluorescência, com comprimentos de onda de excitação (λex) em 378 nm e emissão (λem) em 428 nm.
• III- Para o óleo diesel, adicionou-se ao combustível um volume de solução de 1-fenil-2H-furo[3,2-b]benzopiran-2-ona em acetato de butila, de modo que o volume da solução do marcador atingiu apenas cerca de 0,15%, do volume final, e o marcador com concentração final de 1 ppm no combustível; Figura 4 apresenta a curva analítica, relacionando concentração e intensidade de fluorescência, com comprimentos de onda de excitação (λex) em 412 nm e emissão (λem) em 454 nm.

Preparations of each marker, in the respective fuel:

• I- for ethyl alcohol, a volume of solution of 1-bromo-2-iodo-2H-hole [3,2- b] benzopyran-2-one in ethyl acetate was added to the fuel, so that the volume of the solution the marker reached only about 0.15% of the final volume, and the marker with a final concentration of 1 ppm in the fuel; Figure 2 presents the analytical curve, relating concentration and fluorescence intensity, with excitation wavelengths (λex) at 356 nm and emission (λem) at 426 nm.
• II- For gasoline, a volume of a solution of 1-bromo-2H-bore [3,2-b] benzopyran-2-one in ethyl acetate was added to the fuel, so that the volume of the marker solution reached only about 0.15% of the final volume, and the marker with a final concentration of 1 ppm in the fuel; Figure 3 presents the analytical curve, relating concentration and fluorescence intensity, with excitation wavelengths (λex) at 378 nm and emission (λem) at 428 nm.
• III- For diesel oil, a volume of a solution of 1-phenyl-2H-hole [3,2-b] benzopyran-2-one in butyl acetate was added to the fuel, so that the volume of the marker solution it reached only about 0.15% of the final volume, and the marker with a final concentration of 1 ppm in the fuel; Figure 4 presents the analytical curve, relating concentration and fluorescence intensity, with excitation wavelengths (λex) at 412 nm and emission (λem) at 454 nm.

Due to the fluorescent characteristics of these molecules, acting as markers, their presence in fuels (or, alternatively, in solvents used as adulterants) is identified from the respective fluorescences, defined in the absorption and emission wavelengths (λ), identified by fluorescence spectrophotometry equipment, in the 200 to 800 nm range. Thus, it is possible to detect the adulteration of the marked fuel, considering the change in the fluorescence intensity of the original marked fuel with the addition of the adulterant. The following are the most efficient results.

• I- Para o álcool etílico, marcado com 1 ppm de 1-bromo-2-iodo-2H-furo[3,2- b]benzopiran-2-ona, com comprimentos de onda de excitação (λex) em 356 nm e emissão (λem) em 426 nm: adulterante, água; curva analítica da fluorescência, y = -155x + 151, ou seja, decaimento com a adulteração (Figura 5); limite de detecção 2% (Figura 6). Adulterante, metanol;curva analítica da fluorescência, y = -153x + 158, ou seja, decaimento com a adulteração (Figura 7); limite de detecção 2% (Figura 8).
• II- Para a gasolina, marcado com 1 ppm de 1-bromo-2H-furo[3,2-b] benzopiran-2-ona, com comprimentos de onda de excitação (λex) em 378 nm e emissão (λem) em 428 nm: adulterante, tolueno; curva analítica da fluorescência, y=78,1x+51,4, ou seja, aumento com a adulteração (Figura 9); limite de detecção 2% (Figura 10); obs.: a partir de 30% do adulterante já se observa nítida variação da intensidade da cor do combustível, já indicando anormalidade. Adulterante, diesel; curva analítica da fluorescência, y= 1165x + 45, ou seja, aumento com a adulteração (Figura 11); limite de detecção 1% (Figura 12); obs.: a partir de 30% do adulterante já se observa nítida variação da intensidade da cor do combustível. Adulterante, aguarrás; curva analítica da fluorescência, y = 61x + 31, ou seja, aumento com a adulteração (Figura 13); limite de detecção 5% (Figura 14); obs.: a partir de 30% do adulterante já se observa nítida variação da intensidade da cor do combustível. Adulterante, querosene; curva analítica da fluorescência descreve uma parábola, com um aumento da fluorescência até 40%, a partir disto, começa a decair (Figura 15); obs.: a partir de 30% do adulterante já se observa nítida variação da intensidade da cor do combustível, já indicando anormalidade.
• III- Para o óleo diesel, marcado com 1 ppmde 1-fenil-2H-furo[3,2-b]benzopiran-2-ona, com comprimentos de onda de excitação (λex) em 412 nm e emissão (λem) em 454 nm: adulterante, querosene; curva analítica da fluorescência, y = -303x2 + 9,60 + 297, ou seja, diminuição exponencial com a adulteração (Figura 16); limite de detecção 1% (Figura 17). Adulterante, aguarrás; curva analítica da fluorescência, y = -305x + 26,9x + 283, ou seja, diminuição exponencial com a adulteração (Figura 18); limite de detecção 1% (figura 19). Adulterante, óleo residual de fritura; curva analítica da fluorescência, y = -277x + 301, ou seja, diminuição com a adulteração (Figura 20); limite de detecção 1% (Figura 21);

Results of adulteration tests of fuels marked with 1 ppm of marker:

• I- For ethyl alcohol, marked with 1 ppm of 1-bromo-2-iodo-2H-hole [3,2- b] benzopyran-2-one, with excitation wavelengths (λex) at 356 nm and emission (λem) at 426 nm: adulterant, water; analytical fluorescence curve, y = -155x + 151, that is, decay with adulteration (Figure 5); detection limit 2% (Figure 6). Adulterant, methanol, analytical fluorescence curve, y = -153x + 158, that is, decay with adulteration (Figure 7); detection limit 2% (Figure 8).
• II- For gasoline, marked with 1 ppm 1-bromo-2H-bore [3,2-b] benzopyran-2-one, with excitation wavelengths (λex) at 378 nm and emission (λem) at 428 nm: adulterant, toluene; analytical fluorescence curve, y = 78.1x + 51.4, that is, increase with adulteration (Figure 9); detection limit 2% (Figure 10); note: from 30% of the adulterant there is already a clear variation in the intensity of the color of the fuel, already indicating an abnormality. Adulterant, diesel; analytical fluorescence curve, y = 1165x + 45, that is, increase with adulteration (Figure 11); detection limit 1% (Figure 12); note: from 30% of the adulterant there is already a clear variation in the color intensity of the fuel. Adulterant, turpentine; analytical fluorescence curve, y = 61x + 31, that is, increase with adulteration (Figure 13); detection limit 5% (Figure 14); note: from 30% of the adulterant there is already a clear variation in the color intensity of the fuel. Adulterant, kerosene; analytical fluorescence curve describes a parabola, with an increase in fluorescence of up to 40%, from which point it begins to decay (Figure 15); note: from 30% of the adulterant there is already a clear variation in the intensity of the color of the fuel, already indicating an abnormality.
• III- For diesel oil, marked with 1 ppm of 1-phenyl-2H-bore [3,2-b] benzopyran-2-one, with excitation wavelengths (λex) at 412 nm and emission (λem) at 454 nm: adulterant, kerosene; analytical fluorescence curve, y = -303x2 + 9.60 + 297, that is, exponential decrease with adulteration (Figure 16); detection limit 1% (Figure 17). Adulterant, turpentine; analytical fluorescence curve, y = -305x + 26.9x + 283, that is, exponential decrease with adulteration (Figure 18); detection limit 1% (figure 19). Adulterant, residual frying oil; analytical fluorescence curve, y = -277x + 301, that is, decrease with adulteration (Figure 20); detection limit 1% (Figure 21);

Therefore, these marker molecules demonstrated the ability to detect adulterations in the respective fuels, by varying the intensity of fluorescence, just considering that, for gasoline, in the case of kerosene as an adulterant, the behavior of the upward curve begins to change from about 40% adulteration, keeping above the original fluorescence value up to about 60% adulteration; however, the simple visualization of color can already indicate abnormality, from 30% of adulteration.

In addition, the fluorescence spectrophotometry technique is simple, easy to operate, inexpensive, requiring no reagents or inputs and can be performed at the site, that is, at the point of sample collection, which makes it possible to avoid the need for transport of samples, avoiding the high costs of logistics and transportation.

Claims (4)

Use of molecules derived from 2H-bore [3,2-b] benzopyran-2-ones, containing a ring derived from furan and with the presence of halogen and phenyl group (and / or substituted phenyl) as substituents, as markers, characterized for use in powder form, or in solution (solvents: ethyl acetate or butyl acetate), for detecting adulteration of fuels Use of molecules derived from 2H-bore [3,2-b] benzopyran-2-ones as markers, according to claim 1, characterized by using these markers in concentration in ppm levels, in fuels Use of molecules derived from 2H-bore [3,2-b] benzopyran-2-ones as markers, characterized by using measurements of the fluorescence intensity of these molecules, considering excitation wavelengths (λex) in the range between 300 to 450 nm and emission wavelengths (λem) in the range between 350 to 500 nm, to detect adulteration of fuels Use of molecules derived from 2H-bore [3,2-b] benzopyran-2-ones as markers, according to claim 3, characterized by using these fluorescence intensity measurements to detect adulterations of ethyl alcohol, gasoline and diesel, in the adulteration range from 1 to 100%, with detection limits (LD) between 1 and 5%

Images