US20240294836A1

US20240294836A1 - Obtention of random bipolymers based on acrylics with amphoteric fragments for the removal of aqueous dispersion in crude oils

Info

Publication number: US20240294836A1
Application number: US18/480,641
Authority: US
Inventors: César Andrés FLORES SANDOVAL; Flavio Salvador Vázquez Moreno; Gerardo Zavala Olivares; Patricia Pérez Romo; Jorge Alberto García Martínez; Jessica Valeria FUENTES SANTIAGO; Edgar Benedicto ZAMORA GUERRERO; Citlally Janinne Vargas Martínez; Karen Fernanda Tonchez Pérez; Gerardo Nicolas Rodríguez Araujo; Enrique Cevada Maya
Original assignee: Instituto Mexicano del Petroleo
Current assignee: Instituto Mexicano del Petroleo
Priority date: 2023-02-17
Filing date: 2023-10-04
Publication date: 2024-09-05
Also published as: MX2023002067A

Abstract

The present disclosure relates to novel demulsifying agents obtained from the functionalization of random bipolymers based on alkyl acrylate and aminoalkyl acrylate with different acrylic derivatives, using the aza-Michael addition reaction. The amphoteric random acrylic bipolymers were evaluated as demulsifying agents for crude oils with API densities between 10 and 40° API, showing superior performance as breakers, coalescers and clarifiers than the non-functionalized acrylic bipolymer and a commercial formulation based on polyethers.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

This patent application claims priority under 35 U.S.C. Section 119 to Mexican Patent Application No. MX/a/2023/002067, filed Feb. 17, 2023, the entire disclosure of which is incorporated herein by reference.

FIELD

The present disclosure belongs to the field of chemical products for crude oil conditioning, particularly, to basic demulsifying compounds. The present disclosure concerns to the application of random bipolymers based on alkyl acrylic-aminoalkyl acrylic with amphoteric endings to destabilize water-in-crude oil (W/O) emulsions in order to remove the emulsified water and salts—dissolved in the later, on land and on platform separation units for crude oils with gravities from 10 to 40° API.

BACKGROUND OF THE DISCLOSURE

Currently, the production of crude oils with a low API gravity—heavy and extra-heavy—is increasing because of the depletion of light and medium crude oil reserves. During the crude oil extraction process, the dragging of water and salts-dissolved in the water and crystals dispersed in the organic phasic—is an inevitable process. The water present in the crude oil is in form as primary emulsion—water/crude oil, W/O—or as complex emulsions, O/W/O—secondary or tertiary, with irregular shapes, inverted, etc. These emulsions could be microemulsions—droplet size between 0.1 and 100 μm—or nano-emulsions—droplet size less to 0.1 μm, being the latter ones that have been observing more frequently in recently extracted crude oils. It is important to mention that the W/O or O/W/O emulsions present high colloidal stability because of the action of natural surfactants present in the crude oil, mainly, asphaltenes and resins agglomerates, which form a rigid and very stable film around the dispersed water droplets in the crude oil, preventing the coalescence of the water droplets. [1] Asphaltenes present a polyaromatic structure with polar groups, which induce a surfactant activity and, therefore, a great stabilization of emulsion.[2] In addition to this hindrance, the presence of paraffinic agglomerates, which tend to precipitate on the water/crude oil interface, cause the appearance of another barrier that prevents the coalescence of water droplets.
The presence of water and salts in crude oil is harmful, since both contaminates cause major problems such as: (1) corrosion and abrasion in employed equipment and pipes to transport this; (2) scale formation, which creates an obstruction to the flow of crude oil; and, finally, (3) they induce the poisoning of catalysts used during various stages of the chemical treatment of this resource.
About the above, it is essential to eliminate the emulsified water, or, at least, to reduce its volume to a maximum of 0.5 vol %, to fulfill the crude oil export specifications. The separation of the aqueous phase makes possible to eliminate the salts dissolved in it. Because of aforementioned, the crude-oil dehydration process becomes a technological challenge, which must be solved with efficient processes and at a low cost. In this sense, to induce the destabilization of emulsions present in crude oil, and thus, to remove the emulsified water, at industrial level has been applied various treatments—mechanical, thermal, electrical, between others—.[3] However, the treatment based on chemical products is the most employed, both at laboratory and at industrial level; this procedure consists of the addition of some chemical compounds capable of provoking the breakdown of the rigid film—formed by asphaltenes and resins—that surrounds the water droplet. Various chemical compounds have been reported in the literature as demulsifying agents for crude oils. [3]
In this regard, ionic liquids present a good performance for the removal of emulsified water, which is mainly due to the fact that these are amphoteric molecules. However, these have the drawback of a high production cost, which makes them unfeasible to be applied at industrial level; for this reason, their use is mainly restricted at laboratory level. [4-6] On the other hand, demulsifiers based on polyethers have shown good performance to induce the destabilization of the water/crude oil interface. Among the products based on polyethers are the ethoxylated phenolic resins and the ethoxylated nonylphenols, which have been widely used at industrial level. The efficiency of these products to remove the water depends on the length of the alkylic chain and the degree of ethoxylation. [7] It is important to mention that these are frequently dosed as a formulation of ethoxylated phenolic resin/ethoxylated nonylphenol.
Despite its good performance as dehydrating agents, both products present the problem of a low chemical stability in acid medium, because of the terminal hydroxyl groups, —OH, which suffer chemical degradation and lead to null efficiency in the dehydrating process. In addition to this, if the degree of ethoxylation is too high, the partition coefficient (Log P) decreases, therefore, the water solubility increases, which implies a diffusion problem in crude oil. Another factor against of both products is the synthesis process, since these are manufactured under high-temperature and high-pressure conditions. Finally, at worldwide exists an important decline in the production of ethylene oxide, which causes an increase in the cost of production.
Another type of demulsifiers based on polyethers, widely employed a laboratory and industrial level, are the triblock bipolymers of propylene polyoxide (PPO) and ethylene polyoxide (POE).[8-11] In order to have a good diffusion of these products in the organic phase, it is important that the propylene oxide (PO) should be in a higher weight proportion than the ethylene oxide (EO). On the other hand, it should be mentioned that these polymers are applied as a formulation or combination of at least three PPO/PEO basics of different molecular mass, with the main aim that the formulation possesses the three required properties of a good demulsifying agent-breaker, coalescer and clarifier. For this reason, it is necessary to carry out three synthesis processes of triblock bipolymers—each one of two synthesis steps at high temperature and pressure: the first one to form the PPO block and the second one to obtain the PEO block—to only get one formulation, evidently, it becomes an inconvenient for its usage. In addition to this, and as in the case of ethoxylated phenolic resin and ethoxylated nonylphenol, the PEO-PPO-PEO triblock bipolymers present the problem of chemical degradation in acid medium, because of the protonation of the ending hydroxyl groups; besides, in acid medium exists the formation of micelles, which strengthen the bond between the triblock bipolymer and the water molecules, complicating the dehydrating process.
In order to avoid this protonation of the ending hydroxyl groups, the functionalization of these groups has been reported in the literature. The Mexican patent document MX 321203 B [12] and the US patent document U.S. Pat. No. 8,815,960 [13] describe the laboratory-level synthesis procedure for the functionalization of the POE-POP-POE triblock copolymers with aliphatic and/or cyclic secondary amines. The functionalized copolymers were evaluated in a crude oil of 15.9° API, which displayed a better performance in the removal of emulsified water that the FC-1 and FC-2 commercial formulations based on polyethers.
Cendejas et al. firstly assessed the water removal performance of the PEO-PPO-PEO non-functionalized triblock bipolymers, considering different molecular mass, in a heavy crude oil of 15.0° API; noting that, despite presenting a poor performance as demulsifier agents, there is a suitable molecular mass of bipolymer—for this case M _n=2,826 g mol⁻¹—in this specific crude oil. Subsequently, the functionalization of this PEO-PPO-PEO triblock bipolymer was carried out with N-butyl, N-ethanolamine, piperidine or morpholine, to obtain a bifunctionalized bipolymer, where the terminal amine is tri-substituted—tertiary amine.[14]
The bifunctionalized triblock bipolymers were assessed in the same crude oil, determining that the functionalized bipolymer with N-butyl and N-ethanolamine displayed the highest water removal efficiency, removing 90 vol % at a dosage of 500 ppm.
On the other hand, Zamora et al. synthesized PEO-PPO-PEO triblock bipolymers with quaternary ammonium salt endings.[15] Unlike the obtained bipolymers by Cendejas et al., in which the ending fragments correspond to a neutral tertiary amine; about the latter case, there is an ending fragment with an ionic character, which, obviously, generates a different chemical environment in the molecule, mimicking these fragments to an ionic liquid. These triblock bipolymers with quaternary ammonium salts ending were evaluated in two Mexican crude oils—7.5 and 17.8° API—. In this sense, the bipolymers with ending fragment of trioctylammonium benzenesulfonate and quinolinium benzensulfonate showed the best performance in both crude oils; however, the bipolymers with quinolinium endings displayed a higher dehydrating efficiency in the extra-heavy crude oil, since these managed to remove 100 vol % of the emulsified water.
The obtention of the functionalized bipolymers with secondary and tertiary amines described above involves two synthesis stage at laboratory level, with various unit operations in each stage. In order to scale up these products, the Canadian patent document CA 2852863 C [16], the U.S. Pat. No. 10,125,226 B2 [17] and the Mexican patent document MX 368308 B [18] protect the synthesis procedure to functionalize the PEO-PPO-PEO triblock bipolymers with secondary and tertiary amines in reactors with a capacity from 1 to 100 L. The main advantage of this synthesis process is the reduction in the number of unit operations considered in each synthesis step-shorter total synthesis time.
On the other hand, the United State patent document U.S. Pat. No. 11,261,282 B2 protects the obtaining of PEO-PPO-PEO triblock bipolymers with amphoteric endings and their use as demulsifying agents.[19] N,N-Dialkyl amine triblock bipolymers are functionalized with acrylic derivatives by means of the Michael reaction. The amphoteric triblock bipolymers were evaluated in two crude oils of 7.5 and 11.2° API. The presence of amphoteric endings—ionic fragment—confers to the bipolymer a greater capacity to induce, in a more efficient manner, the destabilization of the water/crude oil interface and, therefore, to promote a greater coalescence of the water droplets, surpassing in efficiency to the non-functionalized triblock bipolymer and a commercial formulation based on polyethers.
These functionalizations in the triblock bipolymers avoid the chemical degradation and increase their performance to remove the emulsified water, even when several synthesis steps are required to obtain them. Following this line of research, Fuentes et al. carried out a quantitative structure activity relationship (QSAR) analysis using quantum parameters of amphoteric triblock bipolymers and physicochemical properties of crude oils.[20] Six equations were obtained in the study, V1-V6; however, only the V1 equation fulfilled with the stablished criteria about the external validation, r_m ²>0.5, being in this case r_m ²=0.72; thus, the V1 equation allows obtaining a calculated removal efficiency value for this type of chemical compounds.
In order to get demulsifying agents with a different chemistry to the polyethers, the use of acrylic-based polymers has been reported in the literature. In this sense, Yuan et al. described the assessment of an ionic polyacrylate, based on poly(N-[3-(dimethylamino) propyl] methacryamide) quaternized with 3-chloro-1-propanol to destabilize a crude oil-in-water (O/W) emulsion. It is important to mention that these products are dissolved in water to be applied to the treated system—continuous phase: water; therefore, these cannot be used to destabilize water—in crude oil (W/O) emulsions; where the demulsifying agent must be dissolved in an organic solvent to be applied—continuous phase: crude oil.[21] On the other hand, the CN 101,255,354 patent document describes the performance of bipolymers based on butyl acrylate and acrylic acid as dehydrants of petroleum, synthesized by means of solution polymerization.[22] The acrylic-based bipolymers displayed a good performance as emulsion breakers, as well as good clarification of the aqueous phase.
Cevada et al. described the assessment of two random acrylic bipolymers based on butyl acrylate (BuA) and ethylhexyl acrylate (2-EHA) as demulsifying agents in a heavy Mexican crude oil of 10.2° API.[23] The BuA/2-EHA acrylic bipolymers were synthesized by emulsion polymerization, varying the monomeric ratio at 70/30 and 30/70 wt %, as well as the molecular mass of the synthesized polymers. The bipolymer with 70 wt % of butyl acrylate—hydrophobic monomer—and with an average molecular mass of 11,000 g mol⁻¹displayed the higher removal efficiency of emulsified water.
On the other side, the Mexican patent application document Mx/a/2018/002971,[24] the U.S. Pat. No. 10,793,783 B2,[25] and the Canadian patent document CA 3013494 C [26] report the use of random bipolymers based on alkyl acrylic-carboxyalkyl acrylic, with different monomeric weight ratio, which were evaluated as dehydrating agents for different crude oils. The alkyl acrylic-carboxyalkyl acrylic monomeric ratio of 80/20 wt % exhibited the best performance in the removal of emulsified water in extra-heavy crude oils-6.1 and 7.5° API, being capable of removing 100 vol %, exceeding a commercial formulation based on polyethers.
The Mexican patent application document Mx/a/2020/011505 [27] and the United States patent application document US 2022/0135886 A1 [28] report the use of bipolymers based on ethylen alkanoate-acrylic (labeled as BV), of different molecular mass, as destabilizers of complex emulsions in crude oil blends. The performance of the BV random bipolymers to remove the emulsified water present in a crude oil blend with specific gravity of 20.1° API was compared with the COP-04 ethylen alkanoate-acrylic—bipolymer block—and the FC-01 commercial formulation based on polyethers. The BV random bipolymers showed a higher coalescence rate, reaching the total water removal at 90 min, whereas the COP-04 and FC-01 products managed to remove 93 and 82 vol %, respectively. Therefore, it is notorious that the randomness of the polymeric system gives to the bipolymers a better diffusion in the organic phase, as well as a better interaction in the destabilization of the water/crude oil interface, compared with a block system—based on acrylic or polyether.
On the other hand, the Mexican patent document MX 386485 B, [29] the United State patent document U.S. Pat. No. 10,975,185 B2,[30] and the Canadian patent document CA 2987447 C [31] describe the synthesis to obtain random bipolymers based on alky acrylic-aminoalkyl acrylics with different monomeric compositions; the general structure of these bipolymers is presented in the Formula (1); while the specific case of N-alkylmorpholine is shown in the Formula (2).
where, R₁and R₃radical=hydrogen or methyl; R₂=alkyl group; R₄and R₅=hydrogen, methyl and ethyl; the x and y values range from 2 to 900; whereas that the z value ranges from 1 to 3. Number average molecular masses are in the range from 1,000 to 180,000 g·mol⁻¹. These random bipolymers were assessed as dehydrating agents in crude oils with specific gravities of 12.3, 18.7 and 38.7° API. The random bipolymers with alkyl acrylic-aminoalkyl acrylic weight monomeric ratio of 60/40, 70/30 and 80/20 wt % displayed a good performance to destabilize the water/crude oil interface, completely removing the emulsified water; whereas the FDH-1 commercial formulation—comprised four PEO-PPO-PEO basics of different molecular mass—, presented a lower removal efficiency and coalescence rate.
It is important to reiterate that the presence of water-in-crude oil emulsions is a huge problem for the oil industry, because of this does not only affect the quality of crude oil, but also, this causes a great damage to the facilities—pipes and equipment, as well as in subsequent processes—refining stage. These drawbacks cause a negative economic impact; therefore, it is extremely important for the oil industry to eliminate the water from the crude oil, or, at least, that the water amount could be less that the established for export.
On the basis of what has been described above, it is notorious that random acrylic bipolymers display excellent demulsifying properties for a wide variety of crude oils. Considering this, the present disclosure is related to obtaining a random acrylic bipolymer with amphoteric fragments, which is carried out by the functionalization of random bipolymers based on alkyl acrylic—aminoalkyl acrylic—Formulas (1) and (2); described in the Mexican patent document MX 386485 B,[29] the United State patent document U.S. Pat. No. 10,975,185 B2,[30] and the Canadian patent document CA 2987447 C; [31] with acrylic derivatives through the aza-Michael addition reaction.
The following references provide further background:

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[6] A. O. Ezzat, A. M. Atta, H. A. Al-Lohedan, A. I. Hashem. Synthesis and application of new surface-active poly (ionic liquids) based on 1,3-dialkylimidazolium as demulsifiers for heavy petroleum crude oil emulsions. J. Mol. Liq. 251 (2018) 201-211.
[7] A. M. Al-Sabagh, M. R. Noor E l-Din, S. Abo-E l Fotouh, N. M. Nasser. Investigation of the demulsification efficiency of some ethoxylated polyalkylphenol formaldehydes based on locally obtained materials to resolve water-in-oil emulsions. J. Dispersion Sci. Technol. 30 (2009) 267-276.
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[9] A. Le Follotec, I. Pezron, C. Noik, C. Dalmazzone, L. Metlas-Komunjer. Triblock copolymers as destabilizers of water-in-crude oil emulsions. Colloids Surf., A 365 (2010) 162-170.
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[12] G. Cendejas-Santana, E. A. Flores-Oropeza, L. V. Castro-Sotelo, A. Estrada-Buendía, M. Lozada-y-Cassou, F. S. Vázquez-Moreno. Formulaciones desemulsificantes y deshidratantes para crudos pesados a base de copolímeros en bloques bifuncionalizados con aminas. Patente mexicana MX 321203 B. Jun. 16, 2014.
[13] G. Cendejas-Santana, E. A. Flores-Oropeza, L. V. Castro-Sotelo, A. Estrada-Buendia, M. Lozada-Cassou, F. S. Vázquez-Moreno. Demulsifying and dehydrating formulations for heavy crude oils based on block copolymers bifunctionalized with amines. Patente estadounidense U.S. Pat. No. 8,815,960 B2. Aug. 26, 2014.
[14] G. Cendejas, F. Arreguín, L. V. Castro, E. A. Flores, F. Vázquez. Demulsifying super-heavy crude oil with bifunctionalized block copolymers. Fuel 103 (2013), 356-363.
[15] E. B. Zamora, F. Vázquez, E. I. Hernández, F. Álvarez, G. Zavala, A. López, C. A. Flores-Sandoval. Triblock copolymers functionalized with quaternary ammonium salts as dehydrating agents for heavy and extra-heavy crude oils. J. Dispersion Sci. Technol. 39 (2018) 1502-1509.
[16] C. A. Flores-Sandoval, E. A. Flores-Oropeza, A. López-Ortega, J. G. Hernández-Cortez, A. Estrada-Buendía, L. V. Castro-Sotelo, R. Reyes-Martínez, A. Estrada-Martínez, F. S. Vázquez-Moreno. Scale-up process of bifunctionalized triblock copolymers with secondary and tertiary amines, with application in dewatering and desalting of heavy crude oils. Patente canadiense CA 2852863 C. Nov. 8, 2016.
[17] C. A. Flores-Sandoval, E. A. Flores-Oropeza, A. López-Ortega, J. G. Hernández-Cortez, A. Estrada-Buendía, L. V. Castro-Sotelo, R. Reyes-Martínez, A. Estrada-Martínez, F. S. Vázquez-Moreno. Scale-up process of bifunctionalized triblock copolymers with secondary and tertiary amines, with application in dewatering and desalting of heavy crude oils. Patente estadounidense U.S. Pat. No. 10,125,226 B2. Nov. 13, 2018.
[17] C. A. Flores-Sandoval, E. A. Flores-Oropeza, A. López-Ortega, J. G. Hernández-Cortez, A. Estrada-Buendía, L. V. Castro-Sotelo, R. Reyes-Martínez, A. Estrada-Martínez, F. S. Vázquez-Moreno. Proceso de escalamiento de copolímeros tribloque bifuncionalizados con aminas secundarias y terciarias, con aplicación en la deshidratación y desalado de aceites crudos pesados. Patente mexicana MX 368308 B. Sep. 26, 2019.
[19] C. A. Flores-Sandoval, F. S. Vázquez-Moreno, A. López-Ortega, F. Álvarez-Ramírez, G. Zavala-Olivares, J. V. Fuentes-Santiago, E. B. Zamora Guerrero. PEO-PPO-PEO triblock bipolymers with amphoteric endings as demulsifying agents for heavy crude oils. Patente estadounidense U.S. Pat. No. 11,261,282 B2. Mar. 1, 2022.
[20] J. V. Fuentes, E. B. Zamora, R. Mariath, Z. Li, Z, Xu, F. Vázquez, C. Flores. Dehydrating heavy crude oils with new amphoteric block biopolymers. Energy Fuels 34 (2020) 4307-4317.
[21] S. Yuan, Y. Wang, X. Wang, Y. Wang, S. Liu, M. Duan, S. Fang. Efficient demulsification of cationic polyacrylate for oil-in-water emulsion: Synergistic effect of adsorption bridging and interfacial film breaking. Colloids Surf., A 640 (2022) 128393.
[22] L. Zesheng, Y. Wei, T. Yungfeng, C. Yaping, Non-polyether type thick oil demulsifiying agent and preparation thereof. Patente china CN 101,255,354. May 4, 2011.
[23] E. Cevada, N. Palacios, E. Hernández, L. Castro, A. López, C. Flores, F. Álvarez, F. Vázquez. Novel petroleum demulsifiers based on acrylic random copolymers. J. Dispersion Sci. Technol. 40 (2019) 495-506.
[24] C. A. Flores-Sandoval, A. López-Ortega, E. B. Zamora-Guerrero, F. Álvarez-Ramírez, F. S. Vázquez-Moreno, G. Zavala-Olivares, M. A. Chávez-Mora. Removedores de emulsiones agua/aceite crudo con base en copolímeros aleatorios alquilacrílico-carboxialquilacrílico de masa molecular controlada. Solicitud de patente mexicana Mx/a/2018/002971. Mar. 9, 2018.
[25] C. A. Flores-Sandoval, M. A. Chávez-Mora, E. B. Zamora-Guerrero, A. López-Ortega, G. Zavala-Olivares, F. Álvarez-Ramírez, F. S. Vázquez-Moreno. Water/crude oil removers based on alkylacrylic-carboxyalkylacrylic random copolymers of controlled molecular mass. Patente estadounidense U.S. Pat. No. 10,793,783 B2. Oct. 6, 2020.
[26] C. A. Flores-Sandoval, M. A. Chávez-Mora, E. B. Zamora-Guerrero, A. López-Ortega, G. Zavala-Olivares, F. Álvarez-Ramírez, F. S. Vázquez-Moreno. Water/crude oil removers based on alkylacrylic-carboxyalkylacrylic random copolymers of controlled molecular mass. Patente canadiense CA 3013494 C. Dec. 8, 2020.
[27] E. Gómez-Buendía, J. V. Fuentes-Santiago, E. B. Zamora-Guerrero, C. J. Vargas-Martinez, E. Cevada-Maya, G. Zavala-Olivares, F. Álvarez-Ramírez, F. S. Vázquez-Moreno, C. A. Flores-Sandoval. Bipolímeros de adición con alta aleatoriedad para desestabilización de emulsiones complejas en mezclas de aceites crudos. Solicitud de patente mexicana Mx/a/2020/011505. Oct. 29, 2020.
[28] C. A. Flores-Sandoval, F. S. Vázquez-Moreno, F. Álvarez-Ramírez, G. Zavala-Olivares, E. Gómez-Buendia, E. Cevada-Maya, J. V. Fuentes-Santiago, E. B. Zamora-Guerrero, C. J. Vargas-Martínez. Highly random addition bipolymers for destabilization of complex emulsions in crude oil blends. Solicitud de patente estadounidense U S 2022/0135886 A1. May 5, 2022.
[29] E. I. Hernández-Carbajal, A. López-Ortega, C. A. Flores-Sandoval, F. Álvarez-Ramírez, F. S. Vázquez-Moreno, G. Zavala-Olivares, J. C. Clavel López, R. J. García-Jiménez, Desemulsionantes para aceites crudos con base en copolímeros aleatorios acrílico-aminoacrílico de masa molecular controlada. Patente mexicana MX 386485 B. Sep. 15, 2021.
[30] E. I. Hernández-Carbajal, C. A. Flores-Sandoval, F. Álvarez-Ramírez, A. López-Ortega, R. J. García-Jiménez, G. Zavala Olivares, Clavel J. C. López, F. S. Vázquez Moreno. Demulsifiers for crude oil based on acrylic-aminoacrylic random copolymers of controlled molecular mass. Patente estadounidense U.S. Pat. No. 10,975,185 B2. Apr. 13, 2021.
[31] E. I. Hernández-Carbajal, C. A. Flores-Sandoval, F. Álvarez-Ramírez, A. López-Ortega, R. J. García-Jiménez, G. Zavala Olivares, Clavel J. C. López, F. S. Vázquez Moreno. Demulsifiers for crude oil based on acrylic-aminoacrylic random copolymers of controlled molecular mass. Patente canadiense CA 2987447 C. Aug. 10, 2021.

SUMMARY OF THE DISCLOSURE

In one aspect, a first object of the present disclosure relates to a process for obtaining random acrylic bipolymers with amphoteric endings, which are synthesized by the aza-Michael addition reaction. Once the amphoteric random acrylic bipolymers have been obtained, a second object of the present disclosure is the assessment of these products as dehydrating agents of crude oils with gravities between 10 and 40° API, where the presence of the amphoteric fragment into the bipolymer creates a different environment chemical comparing with the non-functionalized random acrylic bipolymers, inducing in more efficient manner the destabilization of the asphaltenes' and resins' layers-which surround the emulsified water droplets, besides of mimic to an ionic liquid.
In another aspect, the present disclosure relates to random acrylic bipolymers based on alkyl acrylic-aminoalkyl acrylic with amphoteric endings, as dehydrating agents to remove emulsified water in crude oil with gravities from 10 to 40° API, having structural formulas (3) and (4), with molecular masses from 1,900 to 600,000 g·mol⁻¹as follows:

- where:
- R₆=H (hydrogen) or CH₃(methyl);
- R₇=H (hydrogen), CH₃(methyl), alcoxyalkyl radicals such as: C₂H₅O (metoxymethyl), C₃H₇O (2-metoxyethyl), C₄H₉O (2-etoxyethyl), C₄H₉O (3-metoxypropyl), C₅H₁₁O (3-etoxyopropyl), C₅H₁₁O₂(2-(2-metoxyetoxy)ethylil) or C₄H₉O (2-phenoxyethyl); hydroxyalkyl radicals such as: CH₂OH (hydroxymethyl), C₂H₄OH (2-hiydroxyethyl), C₃H₆OH (3-hydroxypropyl), C₄H₈OH (4-hydroxybutyl), C₅H₁₀OH (5-hydroxypentyl), C₆H₁₂OH (6-hydroxyhexyl), C₇H₁₄OH (7-hydroxyheptyl), C₈H₁₆OH (8-hydroxyoctyl), C₉H₁₈OH (9-hydroxynonyl), C₁₀H₂₀OH (10-hydroxydecyl), C₁₁H₂₂OH (11-hydroxyundecyl) or C₁₂H₂₄OH (12-hydroxydodecyl); carboxyalkyl radicals: C₃H₅O₂(2-carboxyethyl), C₄H₇O₂(carboxypropyl), or C₅H₉O₂(carboxybutyl); aminoalkyl radicals such as: CH₂NH₂(methylamino), CH₂CH₂NH₂(2-ethylamino), CH₂CH₂CH₂NH₂(3-propylamino), CH₂N(CH₃)₂(dimethylamino methyl), CH₂CH₂N(CH₃)₂(2-(dimehtylamino)etihyl), CH₂CH₂CH₂N(CH₃)₂(3-(dimethylamino)propyl), CH₂CH₂N(CH₂CH₃)₂(2-(diethylamino)etthyl); or CH₂CH₂CH₂SO₃K (potassium 3-sulfunate);
- x=a number in the range from 2 to 900;
- y=a number in the range from 2 to 900; and
- z=a number in the range from 1 to 3.

In another aspect, the present disclosure relates to a process of synthesizing amphoteric random acrylic bipolymers for use as dehydrating agents for crude oils according to the present disclosure, where the process involves carrying out an aza-Michael addition reaction by dissolving the alkyl acrylic-aminoalkyl acrylic in an organic solvent, where the organic solvent has a boiling point ranging from about 40° C. to about 130° C., and where the organic solvent can include, without limitation, methanol, ethanol, isopropanol, chloroform, benezene and its derivatives, toluene, xylene, and the like.
In one embodiment of the process of the present disclosure, the acrylic derivatives used for functionalization can include, without limitation, acrylic acid, methacrylic acid, 2-methoxyethyl acrylate, 2-phenoxyethyl acrylate, di(ethylene glycol) ethyl ether acrylate, 2-methoxyethyl methacrylate, 2-phenoxyethyl methacrylate, di(ethylene glycol) ethyl ether methacrylate, 2-ethoxyethyl, 2-ethoxyethyl methacrylate, 2-butoxyethyl acrylate, 2-butoxyethyl methacrylate, 2-ethoxymethyl acrylate, 2-ethoxymethyl methacrylate, hydroxymethyl acrylate, 2-hydroxyethyl acrylate, 3-hydroxypropyl acrylate, 4-hydroxybutyl acrylate, 5-hydroxypentyl acrylate, 6-hydroxyhexyl acrylate, 7-hydroxyheptyl acrylate, 8-hydroxyoctyl acrylate, 9-hydroxynonyl acrylate, 10-hydroxydecyl acrylate, 11-undecyl acrylate, 12-dodecyl, hydroxymethyl methacrylate, 2-hydroxyethyl methacrylate, 3-hydroxypropyl methacrylate, 4-hydroxybutyl methacrylate, 5-hydroxypentyl methacrylate, 6-hydroxyhexyl methacrylate, 7-hydroxyheptyl methacrylate, 8-hydroxyoctyl methacrylate, 9-hydroxynonyl methacrylate, 10-hydroxydecyl methacrylate, 11-undecyl methacrylate or 12-dodecyl methacrylate, 2-carboxyethyl acrylate, 3-carboxypropyl acrylate, 4-carboxybutyl acrylate, 2-carboxyethyl methacrylate, 3-carboxypropyl, 4-carboxybutyl methacrylate, 2-ethylamino acrylate, 2-(dimethylamino)ethyl acrylate, 3-propylamino acrylate, 3-(dimethylamino)propyl acrylate, 2-(diethylamino)ethyl acrylate, 2-ethylamino methacrylate, 2-(dimethylamino)ethyl methacrylate, 3-propylamino methacrylate, 3-(dimethylamino)propyl methacrylate, 2-(diethylamino)ethyl methacrylate, 3-sulfonatopropyl acrylate potassium salt, and the like.
In one embodiment of the process of the present disclosure, the functionalization involves the aza-Michael addition reaction, where a molar ratio of random bipolymer based on alkyl acrylic aminoalkyl acrylic/acrylic derivative is in a range from about 1.0/1.0 to 1.0/8.0 the weight percentage of the aminoalkyl acrylate monomer.
In one embodiment of the process of the present disclosure, the acrylic derivative is added under reagent deficiency conditions at a mass flow ranging from between about 1 and about 50 g L⁻¹min⁻¹.
In one embodiment of the process of the present disclosure, the aza-Michael addition reaction is carried out at a reaction temperature ranging from between about 45° C. and about 120° C. for a period ranging from about 2 h to about 12 h.
In another aspect, the present disclosure relates to a method of using the amphoteric random acrylic bipolymers according to the present disclosure, where the method involves dissolving the dry amphoteric random acrylic bipolymer in a suitable organic solvent, where the organic solvent can include, without limitation, dichloromethane, methanol, ethanol, isopropanol, chloroform, acetone, dimethyl sulfoxide, tetrahydrofuran, dioxane, 2-butoxyethanol, 2-butoxyethanol acetate, benzene and its derivatives, toluene, xylene, jet fuel, naphtha, and the like, for its final application as a dehydrating agent in crude oils with gravities ranging from about 10 to about 40° API.
In one embodiment of the method of the present disclosure, the concentration of a solution of the amphoteric random acrylic bipolymer ranges from about 1.0 to about 50.0 wt %.
In one embodiment of the method of the present disclosure, the solution is dosed in the crude oil with a concentration in a range from about 10 to about 2,000 ppm.

BRIEF DESCRIPTION OF THE DRAWINGS

The patent or application file contains at least one drawing executed in color. Copies of this patent or patent application publication with color drawing(s) will be provided by the Office upon request and payment of the necessary fee.

In order to get a better understanding of the random bipolymers based on acrylics with amphoteric fragments for the removal of aqueous dispersions in crude oils and their synthesis procedure in the present disclosure, the content of the drawings is briefly described below:

FIG. 1 shows the dehydrating efficiencies of the amphoteric random acrylic bipolymers: KAm-1-AA—functionalization with acrylic acid (AA)—, KAm1-AMA—functionalization with methacrylic acid (AMA)—, KAm-1-2DMAE—functionalization with 2-(dimethylamino)ethyl acrylate (2DMAE)—, KAm-1-2CEA—functionalization with 2-carboxyethyl acrylate (2CEA)—, KAm-1-2HEA—functionalization with 2-hydroxiethyl acrylate (2HEA)—, KAm-1-2MEA—functionalization with 2-methoxyehtylacrylate (2MEA)—KAm-1-3SPA—functionalization with 3-sulfopropyl acrylate potassium salt (3SPA)—, the KAm-1 bypolymer—non-functionalized, M _n=37,590 g mol⁻¹—, and the FC-01 commercial formulation—based on polyethers—. Demulsifying agents were evaluated in the KAJ heavy crude oil (14.55° API) at a dosage of 1,000 ppm and a temperature of 80° C.

FIG. 2 displays the images of the bottles and the optical micrographs of crude oils after the assessment with the KAm-1-AA—100 vol %—and KAm-1-AMA—89 vol %-amphoteric random acrylic bipolymers. These were compared with the KAm-1 non-functionalized bipolymer—58 vol %—and the FC-01 commercial formulation—42 vol %—. Regarding the sample of crude oil without demulsifying agent—labeled as blank (bottle and micrograph are not shown)—, the emulsion remained stable during the evaluation time; therefore, it is not observed the presence of removed water.

FIG. 3 displays the demulsifying efficiencies of the KAm1-AMA, KAm-1-2DMAE, KAm-1-2CEA, KAm-1-2HEA, KAm-1-2MEA, and KAm-1-3SPA amphoteric random acrylic bipolymers, the KAm-1 non-functionalized bipolymer, and the FC-01 commercial formulation. Demulsifying agents were evaluated in the NA light crude oil (35.3° API) at a dosage of 500 ppm and a temperature of 80° C.

FIG. 4 exhibit the bottles and optical micrographs of crude oil after of the assessment with the KAm-1-AA bipolymer—97 vol %—, the KAm-1 non-functionalized bipolymer—67 vol %—, and the FC-01 commercial formulation—23 vol %.

FIG. 5 present the dehydrating performance of the KAm1-AMA, KAm-1-2DMAE, KAm-1-2CEA, KAm-1-2HEA, KAm-1-2MEA, and KAm-1-3SPA amphoteric random acrylic bipolymers, the KAm-1 non-functionalized bipolymer, and the FC-01 commercial formulation. Demulsifying agents were assessed in the NA light crude oil (35.3° API) at a dosage of 250 ppm and a temperature of 80° C.

FIG. 6 illustrates the bottles and the optical micrographs of crude oil after of the assessment with the KAm-1-AA bipolymer—87 vol %—, which are compared with the KAm-1 non-functionalized bipolymer—57 vol %—and the FC-01 dehydrating commercial formulation—17 vol %.

FIG. 7 shows the dehydrating performance of the KAm4-AMA, KAm-4-2DMAE, KAm-4-2CEA, KAm-4-2HEA, KAm-4-2MEA, and KAm-4-3SPA amphoteric random acrylic bipolymers, the KAm-4 non-functionalized bipolymer—M _n=10,873 g mol⁻¹—, and the FC-01 commercial formulation. Demulsifying agents were evaluated in the CA crude oil (36.3° API) at a dosage of 1,000 ppm and a temperature of 60° C.

FIG. 8 exhibits the bottles and the optical micrographs of the dosed crude oil with the KAm-4-AMA—100 vol %—and KAm-4-3SPA amphoteric bipolymers—100 vol %—, which are compared with the KAm-4 non-functionalized bipolymer—87 vol %—and the FC-01 commercial formulation—79 vol %.

FIG. 9 reports the dehydrating efficiencies for the KAm1-AMA, KAm-1-2DMAE, KAm-1-2CEA, KAm-1-2HEA, KAm-1-2MEA, and KAm-1-3SPA amphoteric random acrylic bipolymer, the KAm-4 non-functionalized bipolymer and the FC-01 dehydrating commercial formulation. Demulsifying agents were assessed in the CA crude oil (36.3° API) at a dosage of 500 ppm and a temperature of 60° C.

FIG. 10 displays the bottles and the optical micrographs of the KAm-4-AMA—98 vol %—and KAm-4-3SPA functionalized bipolymers—98 vol %—, which are compared with the KAm-4 non-functionalized bipolymer—77 vol %—and the FC-01 dehydrating commercial formulation FC-01—77 vol %.

DETAILED DESCRIPTION OF THE DISCLOSURE

In order to respond to the technological challenge that represents the development of demulsifying agents capable of efficiently eliminating the emulsified water present in crude oil, and besides, that will be also chemically resistant to well acid stimulation conditions, the present disclosure consists of novel demulsifying agents obtained for the functionalization of random bipolymers based on alkyl acrylate and aminoalkyl acrylate—protected for the Mexican patent document 386485 B, the U.S. Pat. No. 10,975,185 B2,[30] and the Canadian patent document CA 2987447 C [31], with different acrylic derivatives, by means of the aza-Michael addition reaction. Amphoteric random acrylic bipolymers were assessed as demulsifying agents in crude oils with specific gravities between 10 and 40° API, showing superior performance as breakers, coalescers, and clarifiers than the non-functionalized acrylic bipolymer and a commercial formulation based on polyethers.
Despite the fact the functionalization implying on more reaction stage in the process for obtaining the demulsifying agents object of the present disclosure, it is important to highlight that a single amphoteric random acrylic bipolymer presents the required properties to dehydrate a crude oil: (1) to destabilize the asphaltenes' and resins' barriers—breaker—, (2) to induce more efficiently the coalescence of dispersed water droplets—coalescer—and (3) an excellent clarification of the removed water—clarifier—. This implies clear advantages in terms of the cost-benefit ratio, in contrast to the commercial formulations based on polyethers, in where at least three PEO-PPO-PEO triblock bipolymers of different molecular masses are required to provide the functions as braker, coalescer and clarifying. Likewise, it is important to mention that there are currently periodic deficiencies in the production of ethylene oxide, as well as restrictions on its use.
In addition to the above, the results about the described evaluations as demonstrative examples in the present disclosure show that amphoteric random acrylic bipolymers represent a viable alternative as demulsifying agents capable of removing all the emulsified water present in crude oil, complying with the export specifications, and furthermore, ensuring the integrity of employed equipment for the transport and treatment.
For obtaining the amphoteric random acrylic bipolymers, firstly, it is necessary to synthesize the random bipolymer based on alkyl acrylic-aminoalkyl acrylic of controlled molecular mass by means of emulsion polymerization in a semi-continuous process, following the procedure described in the Mexican patent document MX 386485 B, the U.S. Pat. No. 10,975,185 B2,[30] and the Canadian patent document CA 2987447 C.[31] Formula (1) exhibits the base structure of random bipolymer based on alkyl acrylic-aminoalkyl acrylic protected in the aforementioned documents. Once the bipolymer based on alkyl acrylic-aminoalkyl acrylic (non-functionalized random bipolymer) has been synthesized, the functionalization is carried out by means of the aza-Michael addition reaction, where, firstly, the dried random bipolymer based on alkyl acrylic-aminoalkyl acrylic is dissolved in an organic solvent, whose boiling point is in the range from 40 to 130° C., such as methanol, ethanol, isopropanol, chloroform, benzene and its derivatives, toluene or xylene, individually or in a mixture of them. On the basis of the weight percent of the aminoalkyl acrylic monomer in the random bipolymer, the molar ration of the non-functionalized/acrylic derivative is from 1.0/1.0 to 1.0/8.0. The acrylic derivative must be added slowly under monomer starving conditions, at mass flow between 1 and 50 g·L⁻¹min⁻¹, in order to avoid the Trommsdorff effect. The system is kept at reflux and the reaction temperature is selected in the range from 45 to 120° C., whereas the reaction time is established from 2 to 12 h. After the reaction is complete, the solvent is evaporated at a temperature from 40 to 130° C., to obtain a viscous liquid. Once the amphoteric random acrylic bipolymer is dried, it is dissolved in a suitable organic solvent: dichloromethane, methanol, ethanol, isopropanol, chloroform, acetone, dimethyl sulfoxide, tetrahydrofuran, dioxane, 2-butoxyethanol, 2-butoxyethanol acetate, benzene and its derivatives, toluene, xylene, jet fuel, and naphtha, for its final application as a dehydrating agent in crude oils with gravities from 10 to 40° API. The effective concentration of the amphoteric random acrylic bipolymer in solution can vary between 1.0 and 50.0 wt %; whereas the formulation of the amphoteric random acrylic bipolymer is dosed at a concentration between 10 and 2,000 ppm in crude oils with gravities from 10 to 40° API, in order to destabilize the water-in-crude oil emulsions present in crude oils and thus, to remove the emulsified water.
Formulas (3) and (4) display the model structures of the amphoteric random acrylic bipolymers comprised in the present disclosure.

- where:
- R₆=H (hydrogen) or CH₃(methyl);
- R₇=H (hydrogen), CH₃(methyl), alcoxyalkyl radicals such as: C₂H₅O (methoxymethyl), C₃H₇O (2-methoxyethyl), C₄H₉O (2-ethoxyethyl), C₄H₉O (3-methoxypropyl), C₅H₁₁O (3-ethoxyopropyl), C₅H₁₁O₂(2-(2-methoxyetoxy)ethylil) or C₈H₉O (2-phenoxyethyl); hydroxyalkyl radicals such as: CH₂OH (hydroxymethyl), C₂H₄OH (2-hydroxyethyl), C₃H₆OH (3-hydroxypropyl), C₄H₈OH (4-hydroxybutyl), C₅H₁₀OH (5-hydroxypentyl), C₆H₁₂OH (6-hydroxyhexyl), C₇H₁₄OH (7-hydroxyheptyl) C₈H₁₆OH (8-hydroxyoctyl), C₉H₁₈OH (9-hydroxynonyl), C₁₀H₂₀OH (10-hydroxydecyl), C₁₁H₂₂OH (11-hydroxyundecyl) or C₁₂H₂₄OH (12-hydroxydodecyl); carboxyalkyl radicals: C₃H₅O₂(2-carboxyethyl), C₄H₇O₂(carboxypropyl), C₅H₉O₂(carboxybutyl); aminoalkyl radicals such as: CH₂NH₂(methylamino), CH₂CH₂NH₂(2-ethylamino), CH₂CH₂CH₂NH₂(3-propylamino), CH₂N(CH₃)₂(dimethylaminomethyl), CH₂CH₂N(CH₃)₂(2-(dimehtylamino)ethyl), CH₂CH₂CH₂N(CH₃)₂(3-(dimethylamino)propyl), CH₂CH₂N(CH₂CH₃)₂(2-(diethylamino)ethyl); or CH₂CH₂CH₂SO₃K (3-sulfopropyl potassium salt);
- x=a number in the range from 2 to 900;
- y=a number in the range from 2 to 900;
- z=a number in the range from 1 to 3;

Number molecular masses of the bipolymers are considered in the range from 1,900 to 600,000 g·mol⁻¹.
Amphoteric random acrylic bipolymers object of the present disclosure are added in effective amounts that vary between 10 and 2,000 ppm to crude oils with gravities of 10 to 40° API.
The present disclosure will be described with reference to a specific number of examples, which will be only considered as illustrative and not restrictive. Amphoteric random acrylic bipolymers were characterized using the following instrumental methods:

- 1.—Size exclusion chromatography (SEC) was obtained employing an Agilent™ model 1100 size exclusion chromatograph, with a PLgel column and using tetrahydrofuran (THF) as eluent, in order to obtain the number average molecular masses of bipolymers, as well as their polydispersity indexes (/).
- 2.—. Fourier transform infrared spectroscopy (FTIR) was obtained using a Thermo Nicolet™ AVATAR 330 Fourier transform infrared spectrometer, employing the film technique method with KBr. The data were processed employing the OMNIC™ 7.0 software.
- 3. Nuclear magnetic resonance (NMR) was recorded employing a Bruker™ spectrometer AVANCE NEO model of 600 MHZ, with a frequency of 600 MHz and 150 MHz for the ¹H and ¹³C spectra, respectively. Deuterated chloroform (CDCl₃) was used as solvent and tetramethylsilane (TMS) was used as reference. In each case, 150 mg of bipolymer was dissolved in 0.5 mL of deuterated chloroform.

The KAm-1 y KAm-4 random bipolymers based on alkyl acrylic-aminoalkyl acrylic were synthesized considering an alkyl acrylic/aminoalkyl acrylic monomeric weigh ratio of 60/40 wt %, where the alkyl acrylic monomer corresponds to butyl acrylate (R₁=hydrogen; R₂=n-butyl) and the aminoalkyl acrylic monomer corresponds to 2-(dimethylamino) ethyl acrylate (R₃=hydrogen; R₄and R₅=methyl; z=2). For the KAm-1 random bipolymer (M _n=37,590 g·mol⁻¹) was obtained employing 1 wt % of molecular agent, whereas for the KAm-4 random bipolymer (M _n=10,873 g·mol⁻¹) was obtained employing 4 wt % of molecular agent. Table 1 lists the values of number average molecular mass and polydispersity indexes of the amphoteric random acrylic bipolymers: KAm-1-AA—functionalization with acrylic acid (AA)—, KAm1-AMA—functionalization with methacrylic acid (AMA)—, KAm-1-2DMAE—functionalization with 2-(dimethylamino)ethyl acrylate (2DMAE)—, KAm-1-2CEA—functionalization with 2-carboxyethyl acrylate (2CEA)—, KAm-1-2HEA—functionalization with 2-hidroxyethyl acrylate (2HEA)—, KAm-1-2MEA—functionalization with 2-metoxyethyl acrylate (2MEA)—and KAm-1-3SPA—functionalization with 3-sulfopropyl acrylate salt potassium (3SPA).

TABLE 1

Number average molecular masses (M _n) and polydispersity
indexes (l) obtained by SEC of the amphoteric random acrylic
bipolymers synthesized with 1 wt % (KAm-1 series).

	M _n	Polydispersity
Amphoteric bipolymer	(g · mol⁻¹)	index (l)

KAm-1-AA	42,451	1.39
KAm-1-AMA	40,985	1.31
KAm-1-2CEA	43,997	2.11
KAm-1-2HEA	44,044	1.75
KAm-1-3SPA	47,977	1.87
KAm-1-2MEA	45,714	2.18
KAm-1-2DMAE	42,580	1.42

Table 2 depicts the values of number average molecular mass and the polydispersity index of the amphoteric random acrylic bipolymers: KAm-4-AA—functionalization with acrylic acid (AA)—, Kam4-AMA—functionalization with methacrylic acid (AMA)—, KAm-4-2DMAE—functionalization with 2-(dimethylamino)ethyl acrylate (2DMAE)—, KAm-4-2CEA—functionalization with 2-carboxyethyl acrylate (2CEA)—, KAm-4-2HEA—functionalization with 2-hidroxyethyl acrylate (2HEA)—, KAm-4-2MEA—functionalization with 2-metoxyethyl acrylate (2MEA)—and KAm-4-3SPA—functionalization with 3-sulfopropyl acrylate salt potassium (3SPA).

TABLE 2

Number average molecular masses (M _n) and polydispersity
indexes (l) obtained by SEC of the amphoteric random acrylic
bipolymers synthesized with 4 wt % (KAm-4 series).

	M _n	Polydispersity
Amphoteric bipolymer	(g · mol⁻¹)	index (l)

KAm-4-AA	12,385	1.26
KAm-4-AMA	11,167	1.35
KAm-4-2CEA	13,955	1.96
KAm-4-2HEA	13,256	1.85
KAm-4-3SPA	15,939	1.68
KAm-4-2MEA	15,238	1.82
KAm-4-2DMAE	13,689	1.58

Examples

The following examples are presented to illustrate the spectroscopic characteristic of amphoteric rando acrylic bipolymers applied as dehydrating agents in crude oils with gravities from 10 to 40° API. These examples should not be considered as limiting to what is claimed here.
Synthesis of amphoteric random acrylic bipolymer: aza-Michael addition reaction. 0.230 a 0.732 mmol of the KAm-1 or KAm-4 random bipolymer and 150 mL of organic dissolvent are added in a flat-bottom flask. Subsequently, from 0.230 to 2.928 mmol of acrylic derivative—acrylic acid (AA), methacrylic acid (AMA), 2-carboxyethyl acrylate (2CEA), 2-hydroxyethyl acrylate (2HEA), 2-methoxyethyl acrylate (2MEA), (2-dimethylamino) ethyl acrylate (2DMAE), or 3-sulfopropyl acrylate potassium salt (3SPA)—is added into the flat-bottom flask. Afterwards, the temperature is increased between 45 and 120° C., depending on the boiling point of the employed solvent. The reaction mixture is kept at constant reflux for a period from 2 to 12 h. Once the reaction is completed, the solvent is evaporated at a temperature from 40 to 130° C., in order to obtain a viscous liquid.
KAm-1-AA bipolymer. I.R. ν cm⁻¹: 3,355; 3,033; 2,963; 2,942; 2,872; 2,746; 2,507; 1,947; 1,730; 1,596; 1,463; 1,372; 1,253; 1,176; 1,098; 1,028; 1,007; 939; 841; 812; and 741.
¹H NMR (CDCl₃) δ ppm: 0.94, 1.36, 1.60, 1.91, 2.28, 2.69, 2.87, 3.10, 3.40, 3.45, 3.60, 4.02.
¹³C NMR (CDCl₃) δ ppm: 13.75, 14.15, 19.12, 30.53, 30.62, 34.49-36.74, 41.44, 43.60, 51.48, 55.55, 62.07, 62.14, 64.41, 64.49, 65.41, and 174.50.
KAm-1-AMA bipolymer. I.R. ν cm⁻¹: 3,307; 3,034; 2,958; 2,935; 2,874; 2,744; 2,546; 1,954; 1,734; 1,633: 1,589; 1,456; 1,377; 1,255; 1,169; 1,119; 1,066; 1,022; 941; 839; 806; and 742.
¹H NMR (CDCl₃) δ ppm: 0.94, 1.37, 1.59, 1.92, 1.93, 2.29, 2.34, 2.86, 3.15, 3.16, 3.45, 3.60, 3.92, and 4.02.
¹³C NMR (, CDCl₃) δ ppm: 13.70, 14.14, 18.49, 19.07, 30.56, 34.59-36.72, 41.43, 41.46, 43.56, 51.44, 56.52, 60.41, 60.88, 61.13, 64.42, 66.79, and 174.55.
KAm-1-2CEA bipolymer. I.R. ν cm⁻¹: 3,348; 3,037; 2,962; 2,935; 2,875; 2,744; 2,557; 1,948; 1,736; 1,635; 1,589; 1,466; 1,402; 1,261; 1,176; 1,066; 995; 945; 820; and 742.
¹H NMR (CDCl₃) δ ppm: 0.93, 1.37, 1.59, 1.63, 1.90, 2.26, 2.57, 2.67, 2.86, 3.12, 3.16, 3.88, 3.93, 3.96, 4.03, and 4.41.
¹³C NMR (CDCl₃) δ ppm: 13.76, 14.15, 19.13, 30.66, 33.80, 34.12-36.66, 37.50, 41.44, 43.60, 51.53, 55.66, 56.34, 59.90, 60.25, 60.34, 64.47, 65.61, and 174.53.
KAm-1-2HEA bipolymer. I.R. ν cm⁻¹: 3,342; 3,037; 2,960; 2,935; 2,874; 2,538; 1,961; 1,736; 1,597; 1,462; 1,379; 1,257; 1,171; 1,096; 1,063; 941; 887; 839; 810; and 741.
¹H NMR (CDCl₃) δ ppm: 0.94, 1.37, 1.60, 1.62, 1.91, 2.27, 2.69, 2.70, 2.88, 3.12, 3.45, 3.59, 3.83, 3.96, 3.97, 4.04, 4.17, and 4.31.
¹³C NMR (CDCl₃) δ ppm: 13.75, 14.14, 19.12, 30.44, 30.64, 34.22-36.68, 41.46, 43.38-43.64, 51.47, 55.57, 61.11, 63.04, 63.46, 64.42, 65.48, 67.24, 69.72, and 174.54.
KAm-1-2MEA bipolymer. I.R. ν cm⁻¹: 3,363; 3,036; 2,958; 2,933; 2,874; 2,511; 1,973; 1,736; 1,595; 1,466; 1,379; 1,254; 1,163; 1,101; 941; 843; 810; and 739.
¹H NMR (CDCl₃) δ ppm: 0.95, 1.37, 1.60, 1.61, 1.92, 2.28, 2.37, 2.64, 2.66, 2.83, 3.12, 3.13, 3.48, 3.61, 3.65, 3.86, 3.88, 4.04, 4.05, and 4.16.
¹³C NMR (CDCl₃) δ ppm: 13.71, 14.10, 19.06, 30.57, 30.94, 34.32-36.75, 41.40, 43.59, 45.17, 51.39, 56.21, 57.10, 58.67, 59.59, 61.79, 62.31, 64.40, 64.64, 65.28, 69.82, 70.28, and 174.51.
KAm-1-2DMAE bipolymer. I.R. ν cm⁻¹: 3,369; 3,037; 2,960; 2,933; 2,874; 2,524; 1,994; 1,738; 1,589; 1,460; 1,381; 1,255; 1,167; 1,119; 1,066; 939; 839; 808; 739; 687; and 635.
¹H NMR (CDCl₃) δ ppm: 0.94, 1.38, 1.21, 1.60, 1.64, 1.91, 2.28, 2.31, 2.32, 2.42, 2.53, 2.67, 3.13, 3.15, 3.60, 3.89, 3.99, 4.05, 4.14, 4.19, and 4.20.
¹³C NMR (CDCl₃) δ ppm: 13.70, 14.15, 19.07, 30.56, 33.27, 34.21-36.69, 41.46, 43.05, 44.07, 45.55, 51.48, 55.56, 55.87, 57.35, 57.64, 61.55, 62.22, 62.31, 64.42, 65.45, 67.32, and 174.52.
KAm-1-3SPA bipolymer. I.R. ν cm⁻¹: 3,417; 3,037; 2,962; 2,933; 2,875; 2,538; 1,732; 1,595; 1,464; 1,392; 1,381; 1,190; 1,117; 1,041; 810; 739; 687; and 609.
¹H NMR (CDCl₃) δ ppm: 0.94, 1.37, 1.56, 1.59, 1.60, 1.89, 2.28, 2.43, 2.79, 3.13, 3.70, 3.87, 3.91, 4.03, 4.04, 4.12, and 4.18.
¹³C NMR (CDCl₃) δ ppm: 13.72, 14.13, 19.08, 27.06, 30.60, 32.12, 34.15-36.68, 41.33, 43.66, 44.49, 51.42, 55.56, 56.61, 60.35, 62.06, 62.36, 64.40, 64.84, 65.31, and 174.47.
Assessment of amphoteric random acrylic bipolymers as dehydrating agents in crude oils with gravities from 10 to 40° API. Different concentrated solutions of each of the amphoteric random acrylic bipolymer were prepared from 1.0 to 50.0 wt %, employing solvents whose boiling point is considered in the range between 30 and 250° C., such as: dichloromethane, methanol, ethanol, isopropanol, chloroform, acetone, dimethyl sulfoxide, tetrahydrofuran, dioxane, 2-butoxyethanol, 2-butoxyethanol acetate, benzene and its derivatives, toluene, xylene, jet fuel, and naphtha. Small volumes of solution were added to prevent any influence of solvent in the removal of emulsified water from the evaluated crude oil. Amphoteric random acrylic bipolymers were evaluated at concentrations in the range from 10 to 2,000 ppm. In order to make a comparison of the emulsified water removal efficiency of the amphoteric random acrylic bipolymers, the non-functionalized random acrylic bipolymer—KAm-1 or KAm-4—and the FC-01 dehydrating commercial formulation—based on polyethers, which is widely used in the oil industry—were evaluated simultaneously.
The assessment procedure of amphoteric random acrylic bipolymers as demulsifying agents is described below. Firstly, an aliquot of the solution of one of the amphoteric random acrylic bipolymers, non-functionalized random acrylic bipolymer or the commercial formulation is added into an oblong bottle; subsequently, the crude oil is poured out up to the 100 mL mark. It is important to mention that the homogenization of the crude oil sample—mechanical or manual agitation—should be avoided, since it can strongly alter the droplet size in the emulsion. Additionally, to one bottle is added the amount of the aliquot of xylene, which is labeled as blank—sample without demulsifying agent—. The bottles are placed into a thermal controlled bath between 40 and 90° C., counting this time as the starting point of the evaluation. The measurement of the removed water from the crude oil is carried out every 5 minutes during the first hour; afterwards, every hour during the evaluation time (5 h). Table 3 lists the physicochemical characterization and properties of crude oils that were used in the evaluation of the performance of amphoteric random acrylic bipolymers as dehydrating agents.

TABLE 3

Physicochemical characterization and properties of crude oils.

Property	KAJ	NA	CA

API gravity (°)	14.5^a	35.3	36.3
Salt content (lb · mbb⁻¹)	>151.00^b	3.28^b	38.21^b
Paraffins content (wt %)	1.75	7.43	9.03
Runoff temperature (° C.)	−39	−27	<−45
Water content by destillation	8.0	0.1	0.1
(vol %)
Water and sediments (vol %)	12.0	0.0	0.0
Kinematic viscosity	^c	4.733	4.049
(mm²· s⁻¹) @ 40° C.
Number average molecular mass	447	217	201
by cryoscopy (g · mol⁻¹)
Saturates (wt %)	33.45	38.06	59.42
Aromatics (wt %)	41.32	28.54	21.04
Resins (wt %)	15.74	30.22	18.57
Aspahltenes (wt %)	8.95	3.14	0.93

^aApparent gravity.
^bThe sample was diluted.
^cResults are out of the method.

As an illustrative and non-limiting manner, FIGS. 1, 3, 5, 7, and 9 display the demulsifying efficiencies of amphoteric random acrylic bipolymers in different crude oils.
FIG. 1 shows that the KAm-1-AA, KAm-1-AMA, and KAm-1-2CEA bipolymers displayed excellent coalescence at the beginning of the assessment, keeping a similar performance until 120 min—75 vol %.—; subsequently, whereas the efficiency of the KAm-1-2CEA bipolymer does not change, the KAm-1-AA and KAm-1-AMA bipolymers continue inducing the coalescence of emulsified water droplets, achieving a water removal of 100 and 89 vol %, respectively.
The KAm-1-2MEA bipolymer removed 69 vol % of emulsified water at 90 min of assessment, performance that was maintained throughout the assessment. The KAm-1-2HEA bipolymer and the non-functionalized bipolymer exhibited similar behavior in terms of their removal rate, both of them removed 58 vol % l of emulsified water; however, the KAm-1-2HEA bipolymer reached this efficiency after 120 min of testing, while the KAm-1 bipolymer achieved this efficiency 60 min after.
Finally, the FC-01 commercial formulation barely removed 42 vol % of emulsified water, as well as the KAm-1-3SPA and KAm-1-2DMAE bipolymers, although these bipolymers presented a lower coaelscence rate than the FC-01 formulation up to 240 min of the evaluation. It is important to mention that the functionalization with acrylic acid (AA), methacrylic acid (AMA) and 2-carboxiyethyl acrylic (2CEA) provide to the bipolymer a demulsifying performance in comparison with the KAm-1 non-functionalized bipolymer, therefore, the amphoteric fragment present in the KAm-1-AA, KAm-1-AMA and KAm-1-2CEA bipolymers induces, firstly, a greater diffusion capacity through the organic phase, and secondly, a more efficient destabilization of the asphaltenes' and resins' layers that surround the emulsified water droplets, and hence, a greater coalescence of these water droplets. The higher efficiency of the KAm-1AA bipolymer, compared with the KAm-1-AMA and KAm-1-2CEA bipolymers, is due to the fact that the acrylic acid (AA) monomer presents less molecular volume—V_M=278.85 Å³—comparing with the methacrylic acid (AMA) monomer—V_M=329.35 Å³—and the 2-carboxyethyl acrylate (2CEA) monomer—V_M=475.11 Å³—. Therefore, the molecular volume of Kam-1AA will be less than the other two, which generates less steric hindrance with the asphaltenes' and resins' layers to induce more efficiently their destabilization.
The lower efficiency of the KAm-1-2MEA, KAm-1-2HEA, KAm-1-2DMAE, and KAm-1-3SPA bipolymers is also due to the effect of the higher molecular volume of the 2-methoxyethyl acrylate (2MEA) monomer—V_M=479.65 Å³—, 2-hidroxyethyl acrylate (2HEA) monomer—V_M=420.21 Å³—, 2-(dimethyl) aminoethyl acrylate (2DMAE) monomer—V_M=539.96 Å³—, and 3-sulfopropyl acrylate potassium salt (3SPA) monomer—V_M=4598.78 Å³—. The KAm-1-2MEA bipolymer presents a better performance to remove the emulsified water than the KAm-1-2HEA bipolymer, even though the molecular volume of the 2MEA monomer—V_M=479.65 Å³—is slightly higher than that of the 2HEA monomer—V_M=420.21 Å³—. Although the steric hindrance is an important factor during the destabilization of the asphaltnes' and resins' layers, the 2MEA monomer exhibits a higher partition coefficient— Log P=0.45—than the 2HEA monomer— Log P=0.17—, which confers to the KAm-1-2MEA bipolymer a greater diffusion through the organic phase, and hence, a higher capacity to reach more quickly and efficiently the water/crude oil interface.
FIG. 2 displays an excellent clarification of the removed water when the KAm-1-AA and KAm-1-AMA bipolymers were employed, being noticeably superior to the obtained with the KAm-1 non-functionalized random bipolymer and the FC-01 commercial formulation. In addition to this, it is notorious the excellent removed water/crude oil interface achieved with these bipolymers. On the other hand, the presence of organic agglomerates can be only observed in the micrograph of the treated crude oil with the KAm-1-AA bipolymer; being important to note that the presence of water droplets is not observed. About the micrograph of treated crude oil with the KAm-1-AMA bipolymer—89 vol %—, it can be observed few dispersed water droplets—with a maximum size of 0.8 μm—. On the other hand, it is observable water droplets of approximately 1.5 μm in the micrograph of treated crude oil with the KAm-1 non-functionalized bipolymer, while in the micrograph of treated crude oil with the FC-01 commercial formulation, it can be seen a large number of water droplets surrounded by a halo of asphaltenes in a polydisperse system—whose size vary from 0.1 to 2.0 μm.
FIG. 3 displays the performance in the water removal of amphoteric random acrylic bipolymer, the KAm-1 non-functionalized random acrylic bipolymer and the FC-01 commercial formulation in the NA light crude oil (35.3° API) at 500 ppm. At this dosage, the KAm-1-AA bipolymer exhibited the greatest coalescence rate, reaching a removal of 96 vol % at 240 min of the assessment. On the other hand, the KAm-1-2CEA and KAm-1-2HEA bipolymers showed a similar coalescence rate to that of the KAm-1 bipolymer during the evaluation; however, the KAm-1-2CEA and KAm-1-2HEA bipolymers managed to eliminate 73 and 70 vol % of emulsified water, respectively, exceeding to the KAm-1 bipolymer—67 vol %—. The KAm-1-3SPA and KAm-1-AMA bipolymers displayed the lowest coalescence rate and water removal capacity, barely reaching 23 vol %, same efficiency that the FC-01 commercial formulation. Finally, the efficiency of the KAm-1-MEA and KAm-1-2DMAE bipolymers was less than 10 vol %, as can be observed in the FIG. 3 .
FIG. 4 makes evident the homogeneous interface generated after the treated crude oil with the KAm-1-AA bipolymer, as well as its significant clarifying capacity, which is superior to that of the KAm-1 bipolymer and the FC-01 dehydrating formulation. The clarification of the removed water with the treatment of the KAm-1-2CEA and KAm-1-2HEA bipolymer is similar to that obtained by the KAm-1-AA bipolymer (bottles are not shown in FIG. 4 ). Regarding the optical micrograph of the treated crude oil with the KAm-1-AA bipolymer, it is notorious the presence of few emulsified water droplets with a diameter of 1.7 μm, as well as organic sediments dispersed in the crude oil. Regarding the micrograph of the treated crude oil with the KAm-1 bipolymer, the presence of a highly polydisperse system is evident, with a diameters of emulsified water droplets from <0.1 μm to 1.2 μm. About the micrograph of the treated crude oil with the FC-01 commercial formulation, a polydisperse system of water droplets is presented, whose size vary from <0.1 μm to 0.7 μm.
By decreasing the dosage to 250 ppm in the NA light crude oil—35.3° API—(FIG. 5 ), the KAm-1-AA bipolymer still exhibited the best dehydrating performance, removing 87 vol % of emulsified water. On the other hand, the KAm-1-2CEA, KAm-1-2HEA, and KAm-1 bipolymers continued to show similar coalescence rates between them, reaching a removal efficiency of 67, 60 and 57 vol. %, respectively.
On the other hand, the KAm-1-AMA and KAm-1-3SPA bipolymers barely removed 20 vol % of the emulsified water; however, both surpassed to the FC-01 formulation—17 vol %—. Finally, the KAm-1-2MEA and KAm-1-2DMAE bipolymers once again show the lowest demulsifying performance, removing scarcely 7 vol % of the emulsified water.
FIG. 6 shows the homogeneous interface between the organic and aqueous phases after the treatment with the KAm-1-AA bipolymer, as well as good clarification of the removed water. The KAm-1 non-functionalized bipolymer also exhibits a significant clarifying ability and a homogeneous interface after the treatment of crude oil with this one; however, the difference in the amount of removed water by this demulsifying agent is less in contrast to the KAm-1-AA amphoteric bipolymer. On the other hand, even though the FC-01 commercial formulation shows a good homogeneity of the removed water/crude oil interface, the clarification of removed water is lower than that obtained with the random acrylic bipolmers-amphoteric and non-functionalized. A slightly polydisperse system can be seen in the micrograph of the treated crude oil with the KAm-1-AA amphoteric acrylic bipolymer, with a size of dispersed water droplets from <0.1 to 0.5 μm, as well as a paraffin agglomerate of de 1.0 μm. Regarding the micrograph of the treated crude oil with the KAm-1 non-functionalized bipolymer, a system with high polydispersity is observed, where the droplet size varies from <0.1 μm to 0.9 μm. About the treated crude oil with the FC-01 commercial formulation, a system with high polydispersity is also observed—same droplet size interval as in the case of the KAm-1 bipolymer—, but with a greater amount of emulsified water.
FIG. 7 presents the demulsifying performance of the KAm-4 series—lower molecular mass compared to the KAm-1 series—, in the CA light crude oil (36.3 ºAPI) at 1000 ppm and 60° C. In this case, it is notorious a high coalescence rate at 10 min of assessment, where the removal efficiencies for the KAm-4-AA, KAm-4-AMA, KAm-4-3SPA, and KAm-4-2DMAE amphoteric bipolymers were 87, 96, 98, and 96 vol %, respectively. At this time, the KAm-4 random acrylic bipolymer achieved a removal of 83 vol %; whereas the commercial formulation barely reached 34 vol %. At 15 min of the test, the KAm-4-3SPA bipolymer removed 100 vol % of emulsified water, whereas the KAm-4-AMA bipolymer reached the total water removal at 40 min. The second-best performance was obtained with the KAm-4-2DMAE and KAm-4-2CEA bipolymers, removing 96 vol % at 10 and 90 min of evaluation, respectively. The KAm-14-2HEA bipolymer reached 2 vol % less than the previously mentioned bipolymers, achieving this efficiency at 90 min. The KAm-4-2HEA and KAm-4-2MAE bipolymers exhibited a removal efficiency of 94 and 92 vol % up to 90 and 180 min, respectively, while the KAm-4-AA bipolymer presented the lowest efficiency of the amphoteric bipolymers, removing 91 vol % of emulsified water after 30 min of the test. Regarding the KAm-1 non-functionalized bipolymer, its efficiency was lower than that of the amphoteric random acrylic bipolymers, reaching a maximum removal of 87 vol %, but markedly higher than that obtained by the FC-01 commercial formulation, which only removed 79 vol %. It is notorious in this crude oil that any functionalization presents a better performance than the non-functionalized bipolymer and the polyethers-based formulation. Regarding the KAm-4-3SPA bipolymer, the presence of a double-charged system induces to this a specific chemical environment with greater capacity to destabilize the natural surfactants—0.93 wt % of asphaltenes and 18.57 wt % of resins—present in the CA light crude oil (36.3°API).
FIG. 8 shows that the KAm-4-AMA and KAm-4-3SPA present a homogeneous interface and an excellent performance to clarify the removed water, which is slightly higher than that obtained by the KAm-1 acrylic bipolymer, but highly superior to that achieved with the FC-01 commercial formulation. Regarding the micrographs of the treated crude oil with the KAm-4-AMA and KAm-4-3SPA bipolymers, about the first one, it is notorious the presence of some asphaltene agglomerates between 0.1 and 0.5 μm of length, whereas in the second one, small paraffin agglomerates with a size of 0.1 μm are observed. In the case of the micrograph of the treated crude oil with the KAm-4 non-functionalized bipolymer, it shows the presence of emulsified water droplets with a polydisperse system, where the droplet diameter is from 0.1 μm to 1.1 μm. Finally, the micrograph of the treated crude oil with the FC-01 commercial formulation displays a polydisperse system—but of lower polydispersity than in the case of the KAm-1 bipolymer, whose droplet sizes are in the range between 0.01 and 0.5 μm.
By decreasing the dosage to 500 ppm of the demulsifying agents evaluated in the CA light crude oil (36.3°API) a 60° C., a noticeable decrease in the efficiency to remove the emulsified water was observed (FIG. 9 ). However, an excellent coalescence rate was maintained; 5 after the assessment, the KAm-4-2DMAE bipolymer reached a removal of 93 vol %, efficiency that was kept throughout the test. This water removal efficiency was also achieved with the KAm-4-2MEA and KAm-4-2HEA bipolymers at 10 min and 40 min, respectively. The KAm-4-3SPA bipolymer achieved a maximum removal of 96 vol % at 10 min of assessment, the same efficiency than the KAm-4-AMA bipolymer, but up to 120 min of evaluation. In the same way as what was observed at a dosage of 1,000 ppm, the presence of a double-charged system in the KAm-4-3SPA bipolymer promotes more efficiently the destabilization of the water/crude oil interface. The KAm-4-2CEA bipolymer was able to reach its maximum yield—96 vol %—at 240 min, whereas, at this time, the KAm-4-AA bipolymer reached maximum removal efficiency of 93 vol %. Regarding the KAm-1 non-functionalized bipolymer, it was only able to remove 77 vol % of the emulsified water after 10 min. The FC-1 commercial formulation displayed a slower coalescence rate than KAm-4; however, it achieved the same water removal efficiency than the non-functionalized bipolymer up to 300 min.
The efficiency in the clarification of the removed water with the KAm-4-AMA and KAm-4-3SPA bipolymers is excellent as can be observed in FIG. 10 , being comparable to that obtained at a dosage of 1,000 ppm, even when at a dosage of 500 ppm a maximum removal of 96 vol % was reached The clarification achieved using the KAm-4 bipolymer and the FC-01 commercial formulation is less than that of the amphoteric random acrylic bipolymers. Regarding the micrographs, the presence of few remaining water droplets can be observed in the simples of treated crude oils with the KAm-4-AMA and KAm-4-3SPA bipolymers; where for the first case, there are water droplets in a range from 0.1 to 0.5 μm—only one droplet reaches 3.0 μm, whereas the treated crude oil with the second amphoteric bipolymer has the same droplet size range although the water droplets of largest size present a diameter of approximately 6.0 μm. On the contrary, the micrograph of treated crude oil with the KAm-4 non-functionalized reveals a polydisperse system with water droplets whose diameters range from 0.1 μm to 0.6 μm, while the micrograph of the treated crude oil with the commercial formulation also shows a polydisperse system, with a droplet size range of 0.10 μm to 0.70 μm—with one water droplet of 3.0 μm.

Claims

1. Random acrylic bipolymers based on alkyl acrylic-aminoalkyl acrylic with amphoteric endings, as dehydrating agents to remove emulsified water in crude oil with gravities from 10 to 40° API, comprising structural formulas (3) and (4), with molecular masses from 1,900 to 600,000 g-mol⁻¹as follows:

where:

R₆=H (hydrogen) or CH₃(methyl);

R₇=H (hydrogen), CH₃(methyl), alcoxyalkyl radicals such as: C₂H₅O (metoxymethyl), C₃H₇O (2-metoxyethyl), C₄H₉O (2-etoxyethyl), C₄H₉O (3-metoxypropyl), C₅H₁₁O (3-etoxyopropyl), C₅H₁₁O₂(2-(2-metoxyetoxy)ethylil) or C₈H₉O (2-phenoxyethyl); hydroxyalkyl radicals such as: CH₂OH (hydroxymethyl), C₂H₄OH (2-hiydroxyethyl), C₃H₆OH (3-hydroxypropyl), C₄H₈OH (4-hydroxybutyl), C₅H₁₀OH (5-hydroxypentyl), C₆H₁₂OH (6-hydroxyhexyl), C₇H₁₄OH (7-hydroxyheptyl), C₈H₁₆OH (8-hydroxyoctyl), C₉H₁₈OH (9-hydroxynonyl), C₁₀H₂₀OH (10-hydroxydecyl), C₁₁H₂₂OH (11-hydroxyundecyl) or C₁₂H₂₄OH (12-hydroxydodecyl); carboxyalkyl radicals: C₃H₅O₂(2-carboxyethyl), C₄H₇O₂(carboxypropyl), or C₅H₉O₂(carboxybutyl); aminoalkyl radicals such as: CH₂NH₂(methylamino), CH₂CH₂NH₂(2-ethylamino), CH₂CH₂CH₂NH₂(3-propylamino), CH₂N(CH₃)₂(dimethylamino methyl), CH₂CH₂N(CH₃)₂(2-(dimehtylamino)etihyl), CH₂CH₂CH₂N(CH₃)₂(3-(dimethylamino)propyl), CH₂CH₂N(CH₂CH₃)₂(2-(diethylamino)etthyl); or CH₂CH₂CH₂SO₃K (potassium 3-sulfunate);

x=a number in the range from 2 to 900;

y=a number in the range from 2 to 900; and

z=a number in the range from 1 to 3.

2. A process of synthesizing amphoteric random acrylic bipolymers for use as dehydrating agents for crude oils according with the claim 1, wherein the process comprises carrying out an aza-Michael addition reaction by dissolving the alkyl acrylic-aminoalkyl acrylic in an organic solvent, wherein the organic solvent has a boiling point ranging from about 40° C. to about 130° C., said organic solvent being selected from the group consisting of methanol, ethanol, isopropanol, chloroform, benezene and its derivatives, toluene, and xylene.

3. The process according to claim 2, wherein the acrylic derivatives used for functionalization are selected from the group consisting of: acrylic acid, methacrylic acid, 2-methoxyethyl acrylate, 2-phenoxyethyl acrylate, di(ethylene glycol) ethyl ether acrylate, 2-methoxyethyl methacrylate, 2-phenoxyethyl methacrylate, di(ethylene glycol) ethyl ether methacrylate, 2-ethoxyethyl, 2-ethoxyethyl methacrylate, 2-butoxyethyl acrylate, 2-butoxyethyl methacrylate, 2-ethoxymethyl acrylate, 2-ethoxymethyl methacrylate, hydroxymethyl acrylate, 2-hydroxyethyl acrylate, 3-hydroxypropyl acrylate, 4-hydroxybutyl acrylate, 5-hydroxypentyl acrylate, 6-hydroxyhexyl acrylate, 7-hydroxyheptyl acrylate, 8-hydroxyoctyl acrylate, 9-hydroxynonyl acrylate, 10-hydroxydecyl acrylate, 11-undecyl acrylate, 12-dodecyl, hydroxymethyl methacrylate, 2-hydroxyethyl methacrylate, 3-hydroxypropyl methacrylate, 4-hydroxybutyl methacrylate, 5-hydroxypentyl methacrylate, 6-hydroxyhexyl methacrylate, 7-hydroxyheptyl methacrylate, 8-hydroxyoctyl methacrylate, 9-hydroxynonyl methacrylate, 10-hydroxydecyl methacrylate, 11-undecyl methacrylate or 12-dodecyl methacrylate, 2-carboxyethyl acrylate, 3-carboxypropyl acrylate, 4-carboxybutyl acrylate, 2-carboxyethyl methacrylate, 3-carboxypropyl, 4-carboxybutyl methacrylate, 2-ethylamino acrylate, 2-(dimethylamino)ethyl acrylate, 3-propylamino acrylate, 3-(dimethylamino)propyl acrylate, 2-(diethylamino)ethyl acrylate, 2-ethylamino methacrylate, 2-(dimethylamino)ethyl methacrylate, 3-propylamino methacrylate, 3-(dimethylamino)propyl methacrylate, 2-(diethylamino)ethyl methacrylate, and 3-sulfonatopropyl acrylate potassium salt.

4. The process according to claim 2, wherein the functionalization comprises the aza-Michael addition reaction, where a molar ratio of random bipolymer based on alkyl acrylic aminoalkyl acrylic/acrylic derivative is in a range from about 1.0/1.0 to 1.0/8.0 the weight percentage of the aminoalkyl acrylate monomer.

5. The process according to claim 2, wherein the acrylic derivative is added under reagent deficiency conditions at a mass flow ranging from between about 1 and about 50 g L⁻¹min⁻¹.

6. The process according to claim 2, wherein the aza-Michael addition reaction is carried out at a reaction temperature ranging from between about 45° C. and about 120° C. for a period ranging from about 2 h to about 12 h.

7. A method of using the amphoteric random acrylic bipolymers according to claim 1, comprising dissolving the dry amphoteric random acrylic bipolymer in a suitable organic solvent, wherein the organic solvent is selected from the group consisting of dichloromethane, methanol, ethanol, isopropanol, chloroform, acetone, dimethyl sulfoxide, tetrahydrofuran, dioxane, 2-butoxyethanol, 2-butoxyethanol acetate, benzene and its derivatives, toluene, xylene, jet fuel, and naphtha, for its final application as a dehydrating agent in crude oils with gravities ranging from about 10 to about 40° API.

8. The method according to claim 7, where concentration of a solution of the amphoteric random acrylic bipolymer ranges from about 1.0 to about 50.0 wt %.

9. The method according to claim 8, where the solution is dosed in the crude oil with a concentration in a range from about 10 to about 2,000 ppm.