ITMI981881A1 - USE OF AMINO AZO DYES AS MERCHANTS OF PETROLEUM DISTILLATION PRODUCTS - Google Patents

Description

Description of the industrial invention in the name:

The present invention relates to the use of azo amine dyes, and of their solutions in organic solvents, as pH dependent marking agents, of gasolines, gas oils and in general for petroleum distillation products.

Petrol and diesel are often added in small quantities, from 5 to 40 ppm, of liquid compositions of arching agents, in order to identify the origin of petroleum products or for fiscal reasons.

The marking agents in many cases consist of liquid compositions of azo dyes in organic solvents, which generally color petroleum products a yellow hue.

It is known that the control and identification of the marker is carried out by treating a small aliquot of the petroleum product, depending on the marking agent, with a hydrophilic solution of a base or an acid, which can optionally contain an organic solvent miscible with water.

The labeling agent under these conditions undergoes a pH dependent reaction with color change. The extraction solutions take on more or less intense colors, with shades ranging from red, to violet, to blue.

Among the extractable commercial markers in an etervbasic environment we can mention Mortrace <®> SB and ST (Morton). Sudan Marker <®> 455 (C.l. Solvent Yellow 124 -BASF) is known among those extractable in an acid environment. The latter marker has a high absorbency as defined below, but has the disadvantage of being synthesized with an industrially very expensive process, which in addition to the diazo-copulation reaction also requires a further process step which consists in the condensation reaction with a vinylether. .

Furthermore, other azoamine markers extractable in an acid medium are known, for example those described in the PCT patent application WO 95/17483. Tests carried out by the Applicant have shown that the azoamine markers in which the nitrogen substituents are aliphatic groups, in the acid solution have specific absorbency E <1%> 1 cm, defined as the absorbance referred to a solution at a concentration of 1% w / v of the dye in a 1 cm cell, not elevated. See the examples.

The need was felt to have available marking agents which in the acid extraction solution had high specific absorbance characteristics E <1%> 1 cm at the respective wavelength of maximum absorption, and which could be obtained with a simplified procedure.

The Applicant has unexpectedly and surprisingly found compounds to be used as markers of petroleum distillation products which overcome the aforementioned disadvantages.

The object of the present invention is the use as markers of petroleum distillation products of amino azo dyes of general formula

(THE)

where is it

R <1> is linear or branched alkyl with a number of carbon atoms from 4 to 20;

R <2> and R <3> are independently H, CH3, C2H5, OCH3, OC2H5;

R <4> and R <5> are independently H, CH3, C2H5;

X is H, OH;

and their concentrated compositions with a high dry content in organic solvents, containing from 40 to 100% by weight of said azo dyes.

For the use which is the object of the present invention, preferably in the compounds of formula (I) R <1> is the aliphatic radical -C12H25 or sec.butyl, the substituents R <2> and R <3> are independently hydrogen, CH3, OCH3; R <4> is hydrogen and X is hydrogen or OH, R <5> is hydrogen.

The organic solvent of the high dry content compositions is selected from aromatic hydrocarbons having a number of carbon atoms ranging from 7 to 15, optionally bearing one or more aliphatic C1-C4 chains, and their mixtures, or solvents with greater hydrocarbon polarity mentioned above, comprising in their molecule one or more oxygen-containing functional groups, in which oxygen is bound by simple covalent bonds, such as e.g. ethers, alcohols, and / or with double bond = 0 such as e.g. esters, ketones etc.

Examples of aromatic hydrocarbons usable as solvents of azo dyes are xylene, alkylnaphthalene, the mixture of aromatic hydrocarbons with a number of carbon atoms between 10 and known as Shellsol <®> AB; examples of solvents having a higher polarity than aromatic hydrocarbons and comprising in the molecule one or more functional groups containing oxygen are 2-butoxyethanol, butylcellosolve acetate and diacetone alcohol.

According to the use object of the present invention, the compounds of formula (I) are extracted from the petroleum product by acid solutions of strong, inorganic and / or organic acids, having the following composition (the percentages are by volume%):

5 to 90% of an aqueous solution of a strong acid, with a molarity equal to or greater than 0.5 M; ·

95 to 10% of a water-soluble organic solvent.

If necessary, the extraction operation can be repeated several times to completely extract the marker.

Examples of strong acids are halogenhydric acids, sulfuric acid, nitric acid, phosphoric acid, mono-, di-, trichloroacetic acid.

Examples of water-soluble organic solvents are alcohols such as methyl, ethyl, isopropyl alcohol; polyols such as mono-, di-, polyethylene glycols, glycerin, - ether alcohols such as methoxy-, ethoxy-, butoxy-ethanol; dimethylformamide, dimethylsulfoxide.

Optionally, an additive, soluble in the mixed aqueous / organic acid phase used for the extraction, can be added to decrease the background color of the extraction solution. For example, a salt in an amount between 5 and 20% w / v can be used. Examples are KC1, CaC12, ZnC12, ZnSO4, A1C13.

In the extraction tests carried out by the Applicant to demonstrate the advantages obtainable with the use of the markers of the present invention, in a first series of tests, solutions obtained by diluting the concentrated liquid compositions of the markers in isooctane up to concentration 5 - were used. 20 ppm. These solutions, colored in yellow, have a wavelength at the absorption peak in the range 395 - 410 nm. The acid extraction solutions have a magenta red color with a range of 530 - 545 nm. The tests reported in the examples show that the markers of the invention in the acid extraction solutions have a specific absorbance E <1%> 1 cm, at the same concentration of the azo compound, which is very high, in particular greater than 50%, with respect to to the azoamine markers mentioned above.

For example, the specific absorbance E <1%> 1 cm of the compound N-ethyl-N- (2-hydroxyethyl) -4 - [(dodecylphenyl) -azo] -m-toluidine, in concentrated liquid composition at concentration 0, 1 mol / 70 g, is 775 (λmax = 538 nm) in the acid hydroalcoholic solution used for the extraction (HC1 lON / ethanol 50/50 v / v), while that of the composition containing N, N-diethyl-4 - [(dodecylphenyl) -azo] -m-toluidine. See Table 1 (In the table the concentrations of the markers in the concentrated liquid compositions are 0.1 mol / 70 g of composition, calculated assuming a synthesis yield of 100%).

In a second series of tests, the concentrated compositions of the markers were added to the petroleum product (diesel fuel, see the examples) to give marker concentrations between 0.5 and 10 ppm. The extraction was carried out as described above. The coloring of the extraction solution shifts towards values lower than the previous ones, up to about 480 nm, towards red and orange when the back-depth color is present. However, the peak corresponding to the wavelength of maximum absorption is clearly identifiable even in these conditions.

Without wishing to be bound by any theory in particular, the Applicant believes that the greater specific absorbance of the marking agents of the present invention is due to the association between the hydroxyl group found in the aliphatic substituent groups of nitrogen of these compounds and the organic solvent in the extraction solution.

The markers of the present invention possess in the extraction solvent a high absorbance comparable, at the same concentration, to that of Sudan Marker <®> 455. However, the markers of the present invention can be obtained with a simpler process, as described below.

It has been found by the Applicant that compounds of formula (I) in which R <1> = C4H9 are extractable also with aqueous acids (eg 5 N HCl). However, the intensity of the coloring of the solution is less than that obtained in an aqueous solution mixed with a water-soluble organic solvent.

The markers of the present invention, or the corresponding compositions in organic solvents with a high dry content, are added to the petroleum distillation products in quantities ranging from 0.5 to 50 ppm.

The markers of the present invention can be used in admixture with other markers and / or dyes used in the sector, which are selected from those which do not interfere with the extraction process described above.

The markers of the present invention are synthesized starting from mono-alkyl primary aromatic amines substituted in the ring and from N, N tertiary aromatic amines disubstituted with alkyl chains bearing at least one hydroxyl group.

Raw materials are readily available on the market. Furthermore, the hydroxylated tertiary aromatic amines used in the present synthesis are not classified as toxic.

The process for obtaining the markers, and which allows to obtain at the same time also the relative concentrated compositions with a high dry content in organic solvents, comprises the following steps:

1) diazotization, in hydroalcoholic solution of isopropyl alcohol, with nitrous acid of the primary aromatic amine having the R1 group and obtaining the corresponding diazonium salt;

2) copulation of the diazonium salt with the aromatic amine N, N disubstituted with alkyl chains bearing at least one hydroxyl group, at 0 ° C and a pH between 2 and 5 buffered with a sodium carbonate solution, in the presence of an aromatic solvent as defined above, in which the product that is formed is extracted,

3) recovery of the solution in the organic solvent with a high dry content ready for use.

As an alternative to step 3), the solvent can be evaporated at reduced pressure and the product is obtained.

At the end of step 2), after recovery of the isopropyl alcohol and elimination of the aqueous phase by siphoning, the organic phase is concentrated under vacuum at 115-120 ° C, and clarified by filtering on a sintered filter of medium porosity (porosity G3). If the final solution is too viscous, filtration clarification is carried out before the concentration step.

Examples illustrating the invention are reported below, which are not to be construed as limiting its scope.

EXAMPLE 1

Synthesis of N-ethyl-N- (2-hydroxyethyl) -4- f (dodecylphenyl) azol-mtoluidine (compound C)

(C)

In a 1 liter 4-necked flask, with stirrer and dripper, 54.8 g (0.21 mol) of dodecylaniline CAS [68411-48-3], 80 ml of isopropyl alcohol, 63 ml of 10 N HCl are loaded and crushed ice.

The diazotization of the aromatic amine is carried out by adding for one hour, under stirring, by means of a dropping funnel, 73 ml of an aqueous solution of NaNO2 at 20% w / v. The temperature of the reaction mixture is maintained at 0 ° C with portions of crushed ice. At the end it is left under stirring for another 20 minutes. The diazonium salt solution has a final volume of 350 ml.

In a 1 liter flask with stirrer, n. 2 dropping funnels, add 35.8 g (0.20 moles) of N-ethyl-N- {2-hydroxyethyl) -m-toluidine, 100 ml of water, 20 ml of HC110 N and 100 ml of Shellsol <® > AB. The solution is cooled to 0 ° C by mixing with crushed ice in portions.

The hydroalcoholic solution containing 0.21 moles of the previously prepared diazonium salt of dodecylaniline is added to this mixture at a temperature of 0 ° C under stirring in one hour and 30 minutes, by means of a dropping funnel. Using the other dropping funnel, 160 ml of 20% Na2CO3 (w / v) solution are added simultaneously in a total time of 2 hours and 30 minutes. The pH is between 2 and 5.

The reaction mixture is kept under stirring for a further 4 hours, allowing the temperature to return to room temperature. At the end, the dripping funnels are removed and replaced with a vigreux column connected to a claisen condenser. The water / isopropyl alcohol azeotrope is distilled.

The stirring stops. The phases separate rapidly and the aqueous phase is siphoned. The organic one is recovered and dehydrated by heating at H 5 ° C in a nitrogen stream, under stirring. The solution is subsequently clarified by filtration on a sintered filter (G3), then concentrated by heating to 115 ° C at the residual pressure of 30 mmHg.

140 g of a solution of the dye in Shellsol <®> AB are thus obtained. The dye solution has a concentration of about 66% by weight.

EXAMPLE the

Extraction test of the concentrated liquid composition of dye C diluted with isooctane.

The following are loaded into a 200 ml separating funnel:

50 ml of isooctane containing 22.90 ppm w / v of liquid composition of product C obtained directly from the synthesis preparation and having a calculated concentration of 0.1 mol / 70 g, assuming a quantitative reaction yield (100%).

50 ml of extracting solution, obtained by mixing 50 volumes of HC110 N with 50 volumes of anhydrous ethanol.

The mass is vigorously beaten for 30 seconds. The funnel is left to rest. Two layers quickly separate. The lower hydroalcoholic acid layer is intensely colored in magenta red.

Table I shows the values of E <1%> 1 cm and of in isooctane and in the extraction solution.

EXAMPLE 2

Synthesis of N.N-bis (2-hydroxyethyl) -4- f (dodecylphenyl) azol-mtoluidine (compound D)

(D)

the compound is synthesized according to the method described in Example 1, using g. 54.8 of dodecylaniline (0.21 moles) as a diazotable base.

in a 1 liter flask with stirrer, n. 2 dropping funnels are loaded with 39 g (0.20 moles) of N, N-bis (2-hydroxyethyl) m.toluidine, 100 ml of water and 20 ml of HC110 N, stirring until complete dissolution. 100 ml of Shellsol <®> AB are then added. The solution is cooled to 0 ° C by mixing with crushed ice.

The same procedure described in example 1 is followed up to the filtration of the organic phase on a sintered filter. After filtration, the phase is diluted with a portion of Shellsol <®> AB solvent used to wash the filter, obtaining a total of 180 g of solution.

The solvent is completely removed by evaporation up to 120-125 ° C and a residual pressure of 30 mm Hg, obtaining a residue with a tarry consistency weighing 95 g, which is taken up with 45 g of acetonalcohol to give a solution (140 g) at a concentration of about 65%.

EXAMPLE 2a

Extraction test of the concentrated liquid composition of dye D diluted with isooctane.

We proceed as described in example la.

Table I shows the corresponding values of E <1%> 1 cm and of in isooctane and in the extraction solution. EXAMPLE 3

Synthesis of N.N-bis (2 - hydroxyethyl) -4-f (dodecylphenyl) azol-aniline (compound B)

(B)

The procedure described in example 2 is followed. Diazotation is carried out on the same basis; the coupling agent is N, N-bis (2-hydroxyethyl) aniline.

The final organic solution in Shellsol <®> AB has a weight of 140 g, the concentration of the dye is about 62%. EXAMPLE 3a

Extraction test of the concentrated liquid composition of dye B diluted with isooctane.

One proceeds as described in example 1a.

Table I shows the corresponding values of E <1%> 1 cm and of λmax in isooctane and in the extraction solution. EXAMPLE 4

Synthesis of N-ethyl-N- (2-hydroxyethyl) -4-f (p-sec.butylphenyl) azol-m-toluidine (compound IB)

(IB)

Operating in the same way as in example 1 and using g. 31.3 of p-sec.butylaniline (0.21 moles) as a diazotable base and g. 35.8 (0.2 mol) of N-ethyl-N- (2hydroxyethyl) -m-toluidine as the coupler base, g. 140 of liquid composition based on the azo dye. The dry title is about 50%.

EXAMPLE 4a

Extraction test of the concentrated liquid composition of IB dye diluted with isooctane.

We proceed as described in example la.

Table I shows the corresponding values of E <1%> 1 cm and of in isooctane and in the extraction solution. EXAMPLE 5 (for comparison)

Synthesis of N.N-diethyl-4 - [(p-sec.butylphenyl) -azol-m-toluidine (compound IC)

(IC)

Operating in the same way as in example 1 and using g. 31.3 of p-sec.butylaniline (0.21 moles) as a diazotable base and g. 32.6 (0.2 mol) of N, N-diethyl-m-toluidine as the coupler base, g. 140 of liquid composition based on the azo dye. The dry title is 48%.

EXAMPLE 5a (comparison)

Extraction test of the concentrated liquid composition of the IC dye diluted with isooctane.

We proceed as described in example la.

Table I shows the corresponding values of E <1%> 1 cm and of λmax in isooctane and in the extraction solution. EXAMPLE 6 (for comparison)

Synthesis of N.N-diethyl) -4 - [(dodecylphenyl) azol-m-toluidine (IF compound)

(IF)

Operating in the same way as in example 1 and using g. 54.8 of dodecylaniline (0.21 moles) as a diazotable base and g. 32.6 of N, N-diethyl-m-toluidine (0.2 mol) as the coupler base, g. 140 of liquid composition based on the azo dye with a dry content of about 65%.

EXAMPLE 6a (comparison)

Extraction test of the concentrated liquid composition of the IF dye diluted with isooctane.

We proceed as described in example la.

Table I shows the corresponding values of E <1%> 1 cm and of λmax in isooctane and in the extraction solution. EXTRACTION TESTS OF THE MARKING PRODUCT C (Ex. 1) FROM DIESEL FOR SELF-TRACTION EXAMPLE 7

In a 200 ml separating funnel 50 ml of diesel fuel for motor vehicles are added with 10 ppm w / v of liquid composition of product C (Ex. 1) having a concentration of 0.1 moles / 70 g, and 50 ml of acid solution of extraction, obtained by mixing 25 volumes of HC110 N, 20 volumes of water and 55 volumes of ethanol.

The mass is vigorously beaten for 30 seconds. The funnel is left to rest. Two layers quickly separate. The lower hydroalcoholic acid layer turns red. The absorption spectrum has a pronounced and evident peak at = 533 nm.

EXAMPLE 8

150 ml of diesel fuel, added with 1 ppm w / v of liquid composition of product C and 40 ml of acid extraction solution of Example 7, are loaded into a 250 ml separating funnel.

From the mass, vigorously beaten, a lower acid hydroalcoholic layer clearly separates, which turns red and has a spectrophotometric peak at λmax = 489 nm. EXAMPLE 9

In a 200 ml separating funnel, 100 ml of diesel fuel, added with 5.25 ppm w / v of liquid composition of product C, are treated and beaten with 3 successive 20 ml aliquots of acid extraction solution containing 70 volumes of dimethylformamide and 30 volumes of HCL 10 N.

The three portions are collected as the lower phase and combined to give a clear solution, colored in red, which has a spectrophotometric peak at = 532 nm.

EXAMPLE 10

In a 200 ml separating funnel, 100 ml of diesel for self-rotation, added with 0.5 ppm of liquid composition of product C, are treated and beaten with 3 successive 10 ml portions of the acid extraction solution of Example 9.

The three portions are collected as the lower phase and combined to give a limpid solution, colored in orange red, having a spectrophotometric peak at = 484 nm.

EXAMPLE 11

In a 200 ml separating funnel, 100 ml of diesel fuel for motor vehicles with the addition of 2 ppm w / v of liquid composition of product C, are treated and beaten with 40 ml of acid extraction solution consisting of 90 volumes of ethylene glycol and 10 volumes of HC110 N.

The clear, red colored extraction solution is separated. It exhibits an absorption peak at - 495 nm.

EXAMPLE 12

In a 200 ml separating funnel, 100 ml of diesel fuel for motor vehicles with the addition of 0.5 ppm w / v of liquid composition of product C, are treated and beaten with 20 ml of the acid solution of example II.

The extraction solution, clear and orange-red colored, is separated. It has an absorption peak at = 485 nm.

Table I.

The concentrations of the markers in the compositions concentrated in organic solvents are 0.1 mol / 70 g of composition, calculated assuming a theoretical synthesis yield (100%)

Table II

Claims (9)

CLAIMS 1. USE as markers of petroleum distillation products of amino azo dyes of general formula (I) where is it : R <1> is linear or branched alkyl with a number of carbon atoms from 4 to 20; R <2> and R <3> are independently H, CH3, C2H5, OCH3, OC2H5; R <4> and R <s> are independently H, CH3, C2H5; X is H, OH; and their concentrated compositions with a high dry content in organic solvents, containing from 40 to 100% by weight of said azo dyes. 2 . Use according to claim 1 wherein in the compounds of formula (I) R <1> is the aliphatic radical -C12H2S or sec.butyl, the substituents R <2> and R <3> are independently hydrogen, CH 3, OCH3; R <4> is hydrogen and X is hydrogen or OH, R <5> is hydrogen. 3. use according to claims 1-2 in which the organic solvent of the compositions with a high dry content is selected from aromatic hydrocarbons having a number of compressed carbon atoms from 7 to 15, optionally bearing one or more C1-C4 aliphatic chains, and their mixtures, or solvents comprising in their molecule one or more functional groups containing oxygen, in which oxygen is linked by simple covalent bonds and / or with double bond = O. 4. Use according to claim 3 wherein the organic solvent is selected from the following: xylene, alkylnaphthalene, the mixture of aromatic hydrocarbons with carbon number between 10 and 11, 2-butoxyethanol, butylcellosolve acetate and diacetonalcohol. 5. Use according to claims 1-4 wherein the compounds of formula (I) are extracted from the petroleum product by acid solutions of strong, inorganic and / or organic acids, having the following composition (percentages by volume%): 5 to 90% of an aqueous solution of a strong acid, with a molarity equal to or greater than 0.5 M; 95 to 10% of a water-soluble organic solvent. 6. Use according to claim 5 wherein the water-soluble organic solvent is selected from alcohols, polyols, ether alcohols, dimethylformamide, dimethylsulfoxide. 7. Use according to claims 5-6 wherein a salt is added in an amount comprised between 5 and 20% w / v. 8. Use according to claim 7 wherein the salt is selected from KCl, CaC12, ZnC12, ZnSO4, A1C13. Use according to claims 1-8 wherein the markers, or their corresponding compositions concentrated in organic solvents, are added to the petroleum distillation products in quantities ranging from 0.5 to 50 ppm.