PROCEDURE FOR THE REMOVAL OF FLUORIDATED POLLUTANTS FROM HYDROCARBON EFFLUENTS

Abstract

A process is disclosed for removing fluoridated compounds from any organic medium, for example from alkylation (alkylated) gasoline, which can be applied at the exit of the alkylation process or inside the distillation column of the alkylation process. The process uses extractant chemical agents based on ionic liquids, of general formula C.sup.+A.sup., where C.sup.+ represents an organic or inorganic cation, specifically imidazolium, pyridinium, or ammonium salts, while the anion A represents the halide-type derivatives, iron (III) salts, aluminum (III) salts, acetate, benzoate-acetates, benzoates, hexafluorophosphate, tetra-chloroborate, triflates, bis-triflates and trifluoroacetates. These ionic liquids act as extractant agents to remove fluoridated compounds from the hydrocarbon streams that are produced in the process of alkylation of isubutane with butenes, through a liquid-liquid extraction process, with a reduction of more than 80% in the content of contaminants like organofluoridated hydrocarbons.

Claims

1. A process for removing fluoridated compounds of formula XF, present in hydrocarbon effluents and in alkylation gasoline, where X represents: H, CH.sub.3, C(CH.sub.3).sub.3, (CH.sub.2).sub.7CH.sub.3, C(CH).sub.2(CH.sub.3).sub.4, CH.sub.2(CH.sub.2).sub.10CH.sub.3, (CH.sub.3).sub.3CCH.sub.2CH(CH.sub.3).sub.2, CH.sub.3CH.sub.2C(CH.sub.3)CH.sub.2, CH.sub.3(CH.sub.2).sub.4CH(CH.sub.3).sub.2, or (CH.sub.3).sub.5(CH.sub.2).sub.3, said process comprising: 1. synthesizing an ionic liquid; and 2. contacting the ionic liquid with the alkylation effluent or gasoline to effect a liquid-liquid extraction.

2. The process according to claim 1, wherein the ionic liquid consists of a) a 5- or 6-membered nitrogenous heterocyclic cation containing one or two nitrogen atoms inserted in the ring, as represented by ##STR00028## or a cation formed by a quaternary ammonium group, as represented by ##STR00029## wherein R.sub.1, R.sub.2, R.sub.3 and R.sub.4 represent a hydrogen atom, an alkyl substituent, or organic group functionalized with a chain of 1 to 10 carbon atoms; and b) an organic or inorganic anion including: halogens, transition metal salts, acetates, benzoates, hexafluorophosphate, tetrafluoroborate, triflates, bistriflates and trifluoroacetates.

3. The process according to claim 1, wherein a ratio of ionic liquid to hydrocarbon is between 1:1 and 1:100.

4. The process according to claim 1, wherein a temperature is between 25 C. and 45 C. during the extraction.

5. The process according to claim 1, wherein an extraction capacity of fluoridated compounds is between 50% and 99%.

6. The process according to claim 5, wherein a number of extraction cycles performed to obtain the extraction capacity is from 1 to 50.

7. The process according to claim 5, wherein the extraction capacity is obtained in an extraction time of 1 to 60 minutes per extraction.

8. The process according to claim 1, wherein an extraction capacity of fluoridated compounds is 50% or more, wherein the process includes a batch mode with vigorous agitation or a continuous process mode that emulates an extraction column at an exit of a separation process for removal of the fluoridated compounds in line, from a liquid hydrocarbon stream that results from a process of alkylation of isobutanes with butenes.

9. The process according to claim 3, wherein the ratio of ionic liquid to hydrocarbon is between 1:5 and 1:50.

10. The process according to claim 9, wherein the ratio of ionic liquid to hydrocarbon is 1:10.

11. The process according to claim 6, wherein the number of extraction cycles is between 1 to 20.

12. The process according to claim 7, wherein the extraction time is 1 to 30 minutes per extraction.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0012] The present disclosure is related to the application of ionic liquids with effective properties to remove contaminating fluoridated compounds that are found in the organic phase, in particular those present in gasolines obtained by the process of alkylation of isobutanes with butenes. The disclosure relates to a process for effecting the removal of fluoridated compounds by liquid-liquid extraction (ionic liquid-fluoridated species), which is based on a greater chemical affinity of the fluoridated compounds for the medium containing the ionic liquid, with respect to the hydrocarbon continuous medium in which they are dissolved, without detriment of the hydrocarbon continuous medium. The extraction with vigorous agitation of the two phases, followed by a separation process, causes the transfer of the phase formed by the ionic liquid and, as a result, the total fluorine content is considerably reduced in the hydrocarbon phase, thus releasing the latter of the contaminants that affect its specification as a product.

[0013] The ionic liquids used in this disclosure have the general formula C.sup.+A.sup., where C.sup.+ represents an organic cation, specifically of the following types: alkyl pyridinium, dialkyl imidazolium and tetraalkylammonium; while the anion A.sup. may be of the inorganic type, for example, but not exclusively, halides, nitrates, phosphates, sulfates, salts of some transition metals especially iron and aluminum and other anions of the organic type, such as, for example, but not exclusively, triflates, acetates, benzoates, trifluoroacetate, hexafluorophosphate and tetrafluoroborate.

[0014] The present disclosure uses the synthesis of ionic liquids by two methods. The first is based on the synthesis by a Radziszewski type reaction, from which primary amines, aldehydes and a mineral or organic acid react exothermically in a single step, producing an ionic liquid by condensation [Arduengo III et al., U.S. Pat. No. 5,077,414 (1991), Arduengo III et al., U.S. Pat. No. 6,177,575 B1 (2001)]. The second method consists of two stages, the first stage is based on using the alkylation process of amines by a heating process, both conventional and unconventional, for example through the use of a microwave or ultrasound source, which offer significant advantages as are the elimination of conventional solvents during the alkylation stage, as well as in the purification, hence obtaining products of greater purity and with a more rapid formation, hence increasing the yield of the reactions; it is possible to synthesize stoichiometric quantities, avoiding the excessive use of reagents and decreasing the reaction time, as well as the cost of manufacturing and, subsequently, the second stage consists of exchanging anions, which is obtained by means of a metathesis reaction of the halogenated anion or through the exchange of ion with salts or acids that contain the desired anion.

[0015] In addition, the amounts of the ionic liquid are optimixed, in relation to the amount of hydrocarbon to be treated, thus obtaining outstanding results in the removal of fluoridated compounds with 1:10 ratios of ionic liquid to hydrocarbon, hence being able to reach optimal relations from 1:20 to 1:50, in a temperature range between 25 and 45 C.

EXAMPLES

General Procedure

[0016] The evaluation of the performance of ionic liquids (LIs) to remove fluoridated compounds from alkylation gasoline was evaluated through the liquid-liquid extraction process, using separation funnels made of the highest quality laboratory grade polypropylene copolymer (PPCO), with a capacity of 250 mL and by extraction with vigorous stirring of the ionic liquid and gasoline, in a 1:10 ratio (1 g of LI: 10 g grams of alkylate) at room temperature and 15 minutes extraction, with a stirring speed of 900 rpm and with a phase separation time of 60 minutes. Subsequently, the gasoline and the ionic liquid are separated by decanting, quantitatively determining the amount of HF, using the method 8007-AK Philips Petroleum Co.

[0017] Table 1 shows the removal percentages obtained from alkylation gasoline contaminated with fluoridated compounds, e.g., >150 ppm (HF).

[0018] Some additional benefits in accordance with this disclosure are the optimization of the amounts used in the process of removal of fluoridated compounds, on the use of the ionic liquid in relation to the amount of hydrocarbon, thus obtaining optimum results with 1:10 ratios of ionic liquid to hydrocarbon, thus being able to reach ratios of 1:20 and up to 1:50.

[0019] Once the extraction time and the molar ratio of alkylate/ionic liquid to obtain the highest extraction efficiency of HF were defined, the following extractions were made as illustrated in Tables 5 to 8, with the ionic liquids reported in Table No 0.1; the extraction time was 15 minutes, with a molar ratio of 1/100 Ionic Liquid/Alkylate, respectively; Tables No. 5, 6, 7, 8 show the results corresponding to the percentage of HF extracted, as well as the percentage of extraction after the ionic liquid was regenerated.

Example 1

[0020] A mixture of 1-methylimidazole (0.086 mol) and 1-bromobutane (0.086 mol) was placed in a ball flask with approximately 30 ml of toluene, the flask was fitted with a magnetic stirrer and a reflux system on an electric plate to maintain the temperature of the reaction at 60 C. for 48 hours until two phases are present. The upper phase contains the raw material that did not react, decanted, while the lower phase is the product, which was washed with approximately 60 ml of ethyl acetate. The ethyl acetate and the product are stirred vigorously and separated by means of a separating flask (60 ml2). The residual ethyl acetate is removed by heating the product [BMI] [Br] in a rotary evaporator at 70 C. The pure product is a clear viscous yellow liquid. Performance 95.5%. IR (film): 2963.1575, 1152, 760, 613 cm.sup.1. .sup.1H NMR (300 MHz, D.sub.2O, ppm): 0.92 (t, J=7.4.3H), 1.31 (sx, 2H), 1.86 (q, 2H), 3.92 (s, 3H), 4.22 (t, 2H), 7.49 (dd, 2H), 8.8 (s, 3H). .sup.13C NMR (75 MHz, D.sub.2O, ppm): 13.1, 19.2, 31.7, 36.2, 49.7, 122.7, 123.9, 136.2

[0021] The Ionic liquids are shown in Table 1, which are based on imidazole type rings with different substitutions on the amino groups and having in common the bromide counterion (Table inputs 1-5), were synthesized as indicated in example 1. As shown by Table 1, these liquids have the property for HF removal in the range between 60-70%, which is lower than ionic liquids shown in the following examples of this document.

Example 2

[0022] For the synthesis of [BMI] [NTf.sub.2], 0.01 mol [BMI] [Br] was used, which was transferred to a beaker and dissolved with deionized water, an aqueous solution of 0.01 mol was added to the solution LiNTf.sub.2, and was left stirring for 3 hours. The purification process was followed, by decanting and washing the product with H.sub.2O, since the product is immiscible. The final product is colorless, obtaining a yield of 90%. IR (Film): 3161, 2970, 2878, 1578, 1352, 1196, 1052, 743, 617, 574. .sup.1H NMR (300 MHz, D.sub.2O, ppm): 0.93 (t, 3H), 1.36 (sx, 2H), 1.90 (q, 2H), 4.04 (s, 3H), 4.34 (t, 2H), 7.73 (dd, 2H), 8.99 (s, 1H). .sup.13C NMR (300 MHz, D 2 O, ppm): 12.8, 19.1, 31.9, 35.8, 49.5, 118.1, 122.6, 124.0, 136.6, 206.7

[0023] The list of ionic liquids based on the imidazole ring and type N(Tf).sub.2 counterions follow the synthetic procedures as described above (Table No. 1, entry 23-27). This shows a series of ionic compounds that meet the defined characteristics but are not unique or exclusive to the ionic species mentioned in Table No. 1. These ionic liquids have outstanding properties, as illustrated in Table No. 2, although they are not unique or exclusive to the class of ionic liquids of the present disclosure. EMI.N(Tf).sub.2 liquids have an HF extraction capacity of 86.8%, which decreases to 82.3% in the second extraction cycle, hence reaching 85.5% removal of HF after its regeneration by means of water washing.

Example 3

[0024] The ionic liquids with general formula PMI.N(Tf).sub.2 were synthesized similarly as shown in example 2, and are characterized by having a side chain formed by a propyl radical, with an extraction capacity as illustrated in Table No. 3, wherein it is observed the variation of the percentage of extraction of HF as a function of time, as well as its extraction capacity after regeneration by means of water washing.

[0025] The variation of the extraction capacity with the contact time (10, 15 and 30 minutes) is illustrated in Table No. 4, without limiting the type of extractants of the present disclosure, on the contrary, the ionic liquids EMI.N(Tf).sub.2 and PMI.N(Tf).sub.2 show increasing rates for removal of HF from the alkylated product, as a function of contact time, thus reaching 90% removal when the IL's side chains are shorter, i.e., EMI.N(Tf).sub.2; the HF removal can reach up to 96.7% when the side chain is longer, i.e., PMI.N(Tf).sub.2. The percentage of extraction increases with the contact time for both types of ionic liquids, thus reaching values of 90 and 96% removal after 30 minutes of contact time, respectively.

Example 4

[0026] The synthesis of the ionic liquid [BMI]Cl, was carried out by adding 37% formaldehyde (1 mole) and hydrochloric acid (1 mole) in a 37% aqueous solution to a ball flask with constant agitation for 30 minutes at room temperature. Then, it is left to cool down using an ice bath until temperature is below 10 C., then butylamine (1 mol) and methylamine (1 mol) are added and when the addition is over, it is allowed to reach room temperature, hence it is kept stirring for 30 minutes more, then glyoxal is added slowly in 40% aqueous solution, thus leaving it 30 minutes more, with both mixtures at room temperature. Then, the temperature is increased to 35-40 C. for 5 hours. Hence, this is placed in the roto-evaporator at 70 C. at 50 mbar. In these conditions the yield is 96%. IR (film) 3311, 3123, 2910, 1658, 1561, 1159, 1067 cm-1; .sup.1H NMR (300 MHz, DMSO-d.sub.6, ppm) 3.7-3.3 (m, 4H), 4.4 (m, 4H), 7.8 (d, 2H), 9.23 (s, 1H); .sup.13C NMR (300 MHz) (ppm) 51.66, 58.0, 122.6, 136.6.

[0027] The ionic liquids synthesized by this procedure are shown in Table 1, entry 7-10, varying only the type of amine, in the same Table the percentage of hydrocarbon HF extraction is shown according to the general procedure described in the first section.

Example 5

[0028] For the synthesis of [BMI]CF.sub.3SO.sub.3, 0.01 mol of [BMI][Cl] was synthesized according to example 4, then was transferred to a beaker and dissolved with deionized water, mixed with an aqueous solution 0.01 mol LiCF.sub.3SO.sub.3, hence was kept under stirring for 3 hours. The purification process is followed by washing with deionized H.sub.2O (20 ml2). The product is colorless and not very viscous; the yield was 94%. IR (film): 161, 2970, 2878.1578, 1352, 1196, 1052, 743, 617, 574. .sup.1H NMR (300 MHz, D.sub.2O, ppm): 0.93 (t, 3H), 1.36 (sx, 2H), 1.90 (q, 2H), 4.04 (s, 3H), 4.34 (t, 2H), 7.73 (dd, 2H), 8.99 (s, 1H). .sup.13C NMR (300 MHz, D.sub.2O, ppm) 12.8, 19.1, 31.9, 35.8, 49.5, 118.1, 122.6, 124.0, 136.6, 206.7.

[0029] According to the data shown in Table 1 (entry 16) an ionic liquid with anion CF.sub.3SO.sub.3 presents an HF extraction capacity of 83%.

[0030] The ionic liquids that are not described in this section were synthesized according to example 4, using different types of amines and acids.

[0031] As shown in Table 1, the removal capacity of fluoridated compounds is between 50% and 99% extraction, as well as in Tables 2-8 it is shown that the extraction capacity of the fluoridated compounds with ionic liquids can be determined in a contact time range, as well as the number of extractions per batch of each extraction.

TABLE-US-00001 TABLE 1 Ionic liquids synthesized and evaluated for the removal of HF Total Ionic Liquid Fluoride Acronym cation anion Removal (%) 1 BMIBr [00001] Br.sup. 57 2 MOIBr [00002] Br.sup. 60 3 BVIBr [00003] Br.sup. 67 4 ABIBr [00004] Br.sup. 57 5 2AlBr [00005] Br.sup. 60 6 BPyBr [00006] Br.sup. 73 7 BMICl [00007] Cl.sup. 58 8 HMICl [00008] Cl.sup. 70 9 MOICl [00009] Cl.sup. 70 10 BzMICl [00010] Cl.sup. 78 11 BPyCl [00011] Cl.sup. 66 12 BMIOH [00012] OH.sup. 88 13 BPyOH [00013] OH.sup. 75 14 MHIBF.sub.4 [00014] BF.sub.4.sup. 98 15 BMIN(CN).sub.2 [00015] N(CN).sub.2.sup. 65 16 HMICF.sub.3SO.sub.3 [00016] CF.sub.3SO.sub.3.sup. 83 17 2BICF.sub.3COO [00017] CF.sub.3COO.sup. 99 18 BMICF.sub.3COO [00018] CF.sub.3COO.sup. 98 19 BPyCH.sub.3COO [00019] CH.sub.3COO.sup. 97 20 BMICH.sub.3COO [00020] CH.sub.3COO.sup. 99 21 HMIPhCOO [00021] PhCOO.sup. 99 22 MOIPhCOO [00022] PhCOO.sup. 99 23 EMIN(Tf).sub.2 [00023] N(Tf).sub.2.sup. 87 24 PMIN(Tf).sub.2 [00024] N(Tf).sub.2.sup. 89 25 BMIN(Tf).sub.2 [00025] N(Tf).sub.2.sup. 99 26 HMIN(Tf).sub.2 [00026] N(Tf).sub.2.sup. 98 27 DMIN(Tf).sub.2 [00027] N(Tf).sub.2.sup. 99

TABLE-US-00002 TABLE No. 2 Percentage of HF extraction by the ionic liquid EMI.N(Tf).sub.2 No. of Extractions % of Removal of HF 1 86.8 2 82.3 Regenerated (after 2 cycles) 85.5

TABLE-US-00003 TABLE No. 3 Percentage of extraction of HF by the ionic liquid PMI.N(Tf).sub.2 No. of Extractions % of Removal of HF 1 (10 minutes) 79.1 2 (15 minutes) 88.6 Regenerated (after 2 cycles) 87.8

TABLE-US-00004 TABLE No. 4 Percentage of extraction of HF by by the ionic liquids EMI.N(Tf).sub.2 and PMIN(Tf).sub.2. IL/Extraction time % of Removal of HF EMI.N(TF).sub.2 10 minutes 82.26 EMI.N(TF).sub.2 15 minutes 86.8 EMI.N(TF).sub.2 30 minutes 90.0 PMI.N(TF).sub.2 10 minutes 79.1 PMI.N(TF).sub.2 15 minutes 88.6 PMI.N(TF).sub.2 30 minutes 96.7

TABLE-US-00005 TABLE No. 5 Percentage of extraction of HF by the ionic liquid BMI.N(Tf).sub.2 No. of Extractions % of Removal of HF 9 (15 minutes) 99.7% Regenerated (after 9 cycles) 99%

TABLE-US-00006 TABLE No. 6 Percentage of HF extraction by the ionic liquid HMI.N(Tf).sub.2 No. of Extractions % of Removal of HF 9 (15 minutes) 97.9% Regenerated (after 9 cycles) 97%

TABLE-US-00007 TABLE No. 7 Percentage of extraction of HF by the ionic liquid DMI.N(Tf).sub.2 No. of Extractions % of Removal of HF 14 (15 minutes) 99% Regenerated (after 14 cycles) 97%

TABLE-US-00008 TABLE No. 8 Percentage of extraction of HF by the ionic liquid HMI.CF.sub.3SO.sub.3 No. of Extractions % of Removal of HF 3 (15 minutes) 83% Regenerated (after 3 cycles) 81.3%