RANDOM BIPOLYMERS OF CONTROLLED MOLECULAR MASS BASED ON HYDROXYACRYLATES AND THEIR USE AS DESTABILIZERS OF WATER/OIL EMULSIONS IN CRUDE OILS

Abstract

The present disclosure provide bipolymers, based on alkyl acrylate and hydroxyalkyl acrylate, with high randomness and controlled molecular mass, that are useful as demulsifying and dehydrating agents for crude oil. The synthesis of these bipolymers is carried out in a single stage by emulsion polymerization, a process that, in addition to having moderate reaction conditions, allows the control of the homogeneity of the chain size, the molecular mass, and the demulsifying efficiency. These random bipolymers are soluble in organic phase; therefore, these cannot be carried away by the removed water, and are eliminated in the atmospheric distillation stage. An additional advantage is the superior demulsifying and clarifying efficiency of these random bipolymers compared with the polyether formulations widely used at industrial level. In addition, these random bipolymers provide single molecule that performs three functions: breaker, coalescer and clarifier, in contrast to formulations based on at least three different polyethers.

Claims

1. A random bipolymer of structural formula (1) and a molecular mass of from 2,800 to 638,000 g mol.sup.−1. ##STR00003## wherein: R.sub.1 and R.sub.3 are independently selected from H (hydrogen), and CH.sub.3 (methyl); R.sub.2 is independently selected from: CH.sub.3 (methyl), C.sub.2H.sub.5 (ethyl), C.sub.4H.sub.9 (n-butyl), C.sub.4H.sub.9 (iso-butyl), C.sub.4H.sub.9 (tert-butyl), C.sub.5H.sub.11 (pentyl), C.sub.6H.sub.13 (n-hexyl), C.sub.6H.sub.11 (di(ethylene glycol)ethylether), C.sub.8H.sub.17 (2-ethylhexyl), C.sub.9H.sub.19 (3,5,5-trimethylhexyl), C.sub.8H.sub.17 (n-octyl), C.sub.8H.sub.17 (iso-octyl), C.sub.8H.sub.9 (ethylene glycol phenyl ether), C.sub.10H.sub.21 (n-decyl), C.sub.10H.sub.21 (iso-decyl), C.sub.10H.sub.19 (10-undecenyl), C.sub.10H.sub.19 (tert-butylcyclohexyl), C.sub.12H.sub.25 (n-dodecyl), C.sub.18H.sub.37 (n-octadecyl), C.sub.5H.sub.9O (tetrahydrofurfuryl), C.sub.5H.sub.9O (2-tetrahydropyranyl), C.sub.13H.sub.27 (tridecyl), and C.sub.22H.sub.45 (behenyl), where the aliphatic chain can optionally include up to 35 carbon atoms, as well as heteroatoms of the ether group or benzene type aromatic rings; R.sub.4 is independently selected from: CH.sub.2OH (hydroxymethyl), C.sub.2H.sub.4OH (2-hydroxyethyl), C.sub.3H.sub.6OH (3-hydroxypropyl), C.sub.4H.sub.8OH (4-hydroxybutyll), C.sub.5H.sub.10OH (5-hydroxypentyl), C.sub.6H.sub.12OH (hydroxyhexyl), C.sub.7H.sub.14OH (hydroxyheptyl) C.sub.8H.sub.16OH (hydroxyoctyl), C.sub.9H.sub.18OH (hydroxynonyl), C.sub.10H.sub.20OH (10-hydroxydecyl), C.sub.11H.sub.22OH (11-hydroxyundecyl), and C.sub.12H.sub.24OH (12-hydroxydodecyl), and can optionally include alkyl groups of cyclic or branched-chain from C.sub.1 to C.sub.22; x is from about 1 to about 6300; y is from about 1 to about 6300; and wherein the polymeric subunit of x alkyl-acrylate monomers and the polymeric subunit of y hydroxyalkyl-acrylate monomers can be present in any order.

2. The random bipolymer according to claim 1, wherein the alkyl acrylate monomer used to prepare the bipolymer is selected from the group consisting of: methyl acrylate, ethyl acrylate, butyl acrylate, pentyl acrylate, iso-butyl acrylate, tert-butyl acrylate, hexyl acrylate, 2-ethylhexyl acrylate, 3,5,5-trimethylhexyl acrylate, 4-tert-butylcyclohexyl acrylate, octyl acrylate, iso-decyl acrylate, decyl acrylate, lauryl acrylate, tridecyl acrylate, octadecyl acrylate, behenyl acrylate, methyl methacrylate, ethyl methacrylate, butyl methacrylate, pentyl methacrylate, iso-butyl methacrylate, tert-butyl methacrylate, hexyl methacrylate, 2-ethylhexyl methacrylate, 3,5,5-trimethylhexyl methacrylate, 4-tert-butylcyclohexyl methacrylate, octyl methacrylate, iso-decyl methacrylate, decyl methacrylate, lauryl methacrylate, tridecyl methacrylate, octadecyl methacrylate, and behenyl methacrylate.

3. The random bipolymer according to claim 1, wherein the hydroxyalkyl acrylate monomer used to prepare the bipolymer is selected from the group consisting of: 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-hydroxyundecyl acrylate, 12-hydroxydodecyl acrylate, 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-hydroxyundecyl methacrylate, and 12-hydroxydodecyl methacrylate.

4. The random bipolymer according to claim 1, wherein the bipolymer is prepare by adding 5 the monomers from a vessel containing a pre-emulsion with about 55 to about 99% by weight of the alkyl acrylate monomer and about 1 to about 45% by weight of the hydroxyalkyl acrylate monomer.

5. The use of a random bipolymer according to claim 1 as a dehydrating agent of crude oils.

6. The use according to claim 5, wherein the organic solvents for dissolution are selected from: dichloromethane, methanol, ethanol, isopropanol, chloroform acetone, dimethylsulfoxide, tetrahydrofuran, dioxane, benzene and its derivatives, toluene, xylene, aromatic amines, jet fuel, and naphtha.

7. The use according to claim 5, wherein the solution concentration of the dry random bipolymer is an amount between about 3 and about 55% in weight.

8. The use according to claim 5, where the demulsifier agent dissolutions are dosed at a concentration from about 10 to about 2,000 ppm.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0037] A better understanding of the novel features and advantages of the present disclosure will be obtained by reference to the following detailed description that sets forth illustrative embodiments, in which the principles of the disclosure are utilized, and the accompanying drawings (also “Figure” and “FIG.” herein), of which:

[0038] FIG. 1 shows the performance of random bipolymers based on alkyl acrylate-hydroxyalkyl acrylate as demulsifying agents, which were synthesized with different monomeric weight ratio and with 1 wt % of chain transfer agent, in order to be compared with the FDH-1 commercial formulation based on polyethers. The demulsifying agents were evaluated in the CR-1 heavy crude oil of 21.0° API at a dosage of 1500 ppm.

[0039] FIG. 2 displays the images of the bottles and the micrographs of crude oil samples after the assessment of the random bipolymers based on alkyl acrylate-hydroxyalkyl acrylate in the CR-1 heavy crude oil of 21.0° API. The untreated crude oil sample (without demulsifying agent, labeled as blank) is compared with the BHA-911 random bipolymer which exhibits the highest coalescence rate, reaching 100 vol % in less time than the rest of the BHA bipolymer—, and with the FDH-1 commercial formulation (88 vol %).

[0040] FIG. 3 exposes the performance of the bipolymers based on alkyl acrylate-hydroxyalkyl acrylate as demulsifying agents, with an alkyl acrylate/hydroxyalkyl acrylate weight ratio of 80/20% wt/wt, synthesized with 1, 2 and 4 wt % of chain transfer agent; as well as the FDH-1 commercial formulation. The demulsifying agents were evaluated in the CR-2 extra-heavy crude oil of 7.6° API at a dosage of 1500 ppm.

[0041] FIG. 4 shows the images of the bottles and the micrographs of the remaining emulsion after the assessment of demulsifier agent in the CR-2 extra-heavy crude oil of 7.6° API. It is compared the blank sample with the crude oil samples treated with the BHA-822 random bipolymer (which achieved removal of 100 vol % of the emulsified water), and with the FDH-1 commercial formulation (90 vol %).

[0042] FIG. 5 displays the performance as demulsifying agents of the random bipolymers based on alkyl acrylate-hydroxyalkyl acrylate synthesized with different monomeric weight ratio and with 1 wt % of chain transfer agent, compared with the FDH-1 commercial formulation. Demulsifying agents were evaluated in the CR-3 heavy crude oil of 13.6° API at a dosage of 1000 ppm.

[0043] FIG. 6 shows the images of the bottles and the micrographs of crude oil samples after the assessment of random bipolymers based on alkyl acrylate-hydroxyalkyl acrylate in the C3 heavy crude oil of 13.6° API. It is compared the blank sample with the BHA-821 random bipolymer (which exhibits the highest coalescence rate reaching the 100 vol % in less time than the rest of BHA bipolymers, as well as, an excellent clarification of the removed water), and with the FDH-1 commercial formulation (only 86 vol % of removed water).

[0044] FIG. 7 displays the performance as demulsifying agents of the random bipolymers based on alkyl acrylate-hydroxyalkyl acrylate, synthesized with different monomeric weight ratio and with 2 wt % of chain transfer agent, compared with the FDH-1 commercial formulation. The demulsifying agents were evaluated in the CR-4 light crude oil of 37.3° API at a dosage of 250 ppm.

[0045] FIG. 8 displays the performance as demulsifying agents of the random bipolymers based on alkyl acrylate-hydroxyalkyl acrylate, synthesized with different monomeric weight ratio and 4 wt % of chain transfer agent, compared with the FDH-1 commercial formulation. All demulsifying agents were evaluated in the CR-4 light crude oil of 37.3° API at a dosage of 250 ppm.

[0046] FIG. 9 exhibits the images of the bottles and the micrographs of crude oil after the assessment of the random bipolymers based on alkyl acrylate-hydroxyalkyl acrylate in the CR-4 light crude oil of 37.3° API. Regarding the assessment described in the FIGS. 7 and 8, it is compared with the crude oil without demulsifying agent (blank), with the BHA-822 random bipolymer (which achieved removal of 100 vol % of the emulsified water before than the BHA-912, BHA-732 and BHA-642 bipolymers, with a clarification of removed water similar in all the cases (the images of the bottles of the latter are not shown)), with the BHA-824 bipolymer (which achieved removal of 100% v of the emulsified water before than the BHA-914 bipolymer), and also with the FDH-1 commercial formulation (which scarcely reached 74 vol % of removal of emulsified water).

[0047] FIG. 10 shows the performance as demulsifying agents of the BHA-822 bipolymer and the FDH-1 commercial formulation at a dosage of 1500 ppm in the CR-5 crude oil of 15.2° API, at a pH=7 (solid-filled symbols) and at a pH=2 (unfilled symbols).

DETAILED DESCRIPTION

[0048] The present disclosure provides novel bipolymers (based on alkyl acrylate and hydroxyalkyl acrylate monomers) and with high randomness and controlled molecular mass to be employed as demulsifying and dehydrating agents, in order to break down water-in-crude oil emulsions and remove the emulsified water and the salt dissolved in this last one, specifically, in the separation units set for crude oils (inshore and offshore) with gravities from 7 to 40° API. The random bipolymers based on alkyl acrylate-hydroxyalkyl acrylate of the present disclosure useful as demulsifying and dehydrating agents have structural formula (1) below:

##STR00002## [0049] wherein: [0050] R.sub.1, R.sub.2, R.sub.3 and R.sub.4 are independent radicals, and represent chemical groups as follows: [0051] R.sub.1 and R.sub.3 are independently selected from H (hydrogen), and CH.sub.3 (methyl); [0052] R.sub.2 is independently selected from CH.sub.3 (methyl), C.sub.2H.sub.5 (ethyl), C.sub.4H.sub.9 (n-butyl), C.sub.4H.sub.9 (iso-butyl), C.sub.4H.sub.9 (tert-butyl), C.sub.5H.sub.11 (pentyl), C.sub.6H.sub.13 (n-hexyl), C.sub.6H.sub.11 (di(ethylene glycol)ethylether), C.sub.8H.sub.17 (2-ethylhexyl), C.sub.9H.sub.19 (3,5,5-trimethylhexyl), C.sub.8H.sub.17 (n-octyl), C.sub.8H.sub.17 (iso-octyl), C.sub.8H.sub.9 (ethylene glycol phenyl ether), C.sub.10H.sub.21 (n-decyl), C.sub.10H.sub.21 (iso-decyl), C.sub.10H.sub.19 (10-undecenyl), C.sub.10H.sub.19 (tert-butylcyclohexyl), C.sub.12H.sub.25 (n-dodecyl), C.sub.18H.sub.37 (n-octadecyl), C.sub.5H.sub.9O (tetrahydrofurfuryl), C.sub.5H.sub.9O (2-tetrahydropyranyl), C.sub.13H.sub.27 (tridecyl), and C.sub.22H.sub.45 (behenyl). Generally, the R.sub.2 group aliphatic chain can include up to 35 carbon atoms, as well as heteroatoms of the ether group or benzene type aromatic rings; [0053] R.sub.4 is independently selected from: CH.sub.2OH (hydroxymethyl), C.sub.2H.sub.4OH (2-hydroxyethyl), C.sub.3H.sub.6OH (3-hydroxypropyl), C.sub.4H.sub.8OH (4-hydroxybutyl), C.sub.5H.sub.10OH (5-hydroxyphenyl), C.sub.6H.sub.12OH (hydroxyhexyl), C.sub.7H.sub.14OH (hydroxyheptyl) C.sub.8H.sub.16OH (hydroxyoctyl), C.sub.9H.sub.18OH (hydroxynonyl), C.sub.10H.sub.20OH (10-hydroxydecyl), C.sub.11H.sub.22OH (11-hydroxyundecyl), and C.sub.12H.sub.24OH (12-hydroxydodecyl). Generally, the R.sub.4 hydroxyalkyl monomer can include an alkyl group of cyclic or branched-chain from C.sub.1 to C.sub.22; [0054] wherein also: [0055] x is a number from about 1 to about 6300; [0056] y is a number from about 1 to about 6300; and [0057] wherein the polymeric subunit of x alkyl-acrylate monomers and the polymeric subunit of y hydroxyalkyl-acrylate monomers can be present in any order.

[0058] The random bipolymers typically have number average molecular masses (M.sub.n) ranging from about 2800 to 638000 g mol.sup.−1.

[0059] The present disclosure also provides processes to synthesize and formulate the novel bipolymers, and methods for their use. The dehydrating agents based on the alkyl acrylate-hydroxyalkyl acrylate bipolymers of the present disclosure can be synthesized as latexes using semi-continuous emulsion polymerization, making up firstly a pre-emulsion in an addition tank according to the following proportions: the alkyl acrylate monomer is set up on an interval between about 55.0 and 99.0 wt % and the hydroxyalkyl acrylate monomer is set up on an interval from about 1.0 to 45.0 wt %. The higher proportion of alkyl acrylate monomer confers to the random acrylic bipolymer a higher diffusion in the crude oil, which allows reaching the interface of the water droplet. Once the polymerization reaction is completed, the random acrylic bipolymer in latex form is submitted to a distillation process at a temperature between about 60 and 100° C., in order to obtain a viscous liquid, which is dissolved in an adequate organic solvent with boiling points between about 30 and 250° C., such as: dichloromethane, methanol, ethanol, isopropanol, chloroform, acetone, dimethylsulfoxide, tetrahydrofuran, benzene and its derivatives, toluene, xylene, aromatic amines, jet fuel, and naphtha; individually or as a mixture, for its final application as demulsifying agent of crude oils with gravities ranging from about 7 to 40° API. The concentration of the random bipolymer in the solution is set up on an interval from about 3.0 to 55.0 wt %; whereas the solution dosage in the crude oil can be set up on an interval of concentrations from about 10 to 2000 ppm.

Alkyl Acrylate-Hydroxyalkyl Acrylate

[0060] Alkyl acrylate monomers useful for the synthesis of the bipolymers of the present disclosure include, but are not limited to: methyl acrylate, ethyl acrylate, butyl acrylate, pentyl acrylate, iso-butyl acrylate, tert-butyl acrylate, hexyl acrylate, 2-ethylhexyl acrylate, 3,5,5-trimethylhexyl acrylate, 4-tert-butylcyclohexyl acrylate, octyl acrylate, iso-decyl acrylate, decyl acrylate, lauryl acrylate, tridecyl acrylate, octadecyl acrylate, behenyl acrylate, methyl methacrylate, ethyl methacrylate, butyl methacrylate, pentyl methacrylate, iso-butyl methacrylate, tert-butyl methacrylate, hexyl methacrylate, 2-ethylhexyl methacrylate, 3,5,5-trimethylhexyl methacrylate, 4-tert-butylcyclohexyl methacrylate, octyl methacrylate, iso-decyl methacrylate, decyl methacrylate, lauryl methacrylate, tridecyl methacrylate, octadecyl methacrylate and behenyl methacrylate.

[0061] Hydroxyalkyl acrylate monomers useful for the synthesis of the bipolymers of the present disclosure include, but are not limited to: 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-hydroxyundecyl acrylate, 12-hydroxydodecyl acrylate, 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-hydroxyundecyl methacrylate, 12-hydroxydodecyl methacrylate.

[0062] The random acrylic bipolymers of the present disclosure can be dosed in effective quantities ranging from 10 to 2000 ppm in crude oils with gravities from 7 to 40° API, in order to remove the emulsified water and the dissolved salts.

Examples

[0063] Various features and embodiments of the disclosure are illustrated in the following representative examples, which are intended to be illustrative, and not limiting. Those skilled in the art will readily appreciate that the specific examples are only illustrative of the inventions described more fully in the claims which follow thereafter. Every embodiment and feature described in the application should be understood to be interchangeable and combinable with every embodiment contained within.

[0064] The following examples are shown to illustrate the spectroscopic characteristic of the random bipolymers based on alkyl acrylate-hydroxyalkyl acrylate as dehydrating agents in crude oils with gravities from about 7 to 40° API. These examples must not be considered as limitation of what is claimed here.

[0065] Exemplary bipolymers (based on alkyl acrylate-hydroxyalkyl acrylate) of the present disclosure were synthesized, dried, and characterized using the following instrumental methods: [0066] 1. Size exclusion chromatography (SEC) was carried out in order to obtain the number average molecular masses of bipolymers, as well as their polydispersity indexes (I). An Agilent™ model 1100 size exclusion chromatograph with a PLgel column was employed, using tetrahydrofuran (THF) as eluent. [0067] 2. Fourier transform infrared spectroscopy (FTIR) was used in order to qualitatively identify the functional groups present in random acrylic bipolymers. A Thermo Nicolet™ AVATAR 330 Fourier transform infrared spectrometer was utilized to record the spectra, employing the film technique with a KBr film. The OMNIC™ 7.0 software was used for the processing of spectra. [0068] 3. Nuclear magnetic resonance (NMR) was obtained in order to identify the characteristic chemical shifts of random acrylic bipolymers. A Bruker AVANCE NEO spectrometer was used to record the .sup.1H and .sup.13C spectra at frequencies of 600 MHz and 150 MHz, respectively. A solution in deuterated chloroform (CDCl.sub.3) of each bipolymer was prepared, considering the tetramethylsilane (TMS) as reference.

[0069] Exemplary bipolymers of high randomness based on alkyl acrylate-hydroxyalkyl acrylate of the present disclosure were obtained, and their average molecular mass was determined by SEC, as well as their spectroscopic characteristics of alkyl acrylate-hydroxyalkyl acrylate as shown below in Tables 1, 2, and 3.

[0070] Table 1 reports the results for the poly(alkyl acrylate-hydroxyalkyl acrylate) (R.sub.1 and R.sub.3=hydrogen, R.sub.2=n-butyl R.sub.3=2-hydroxyethyl) corresponding to the BHA-1 series.

TABLE-US-00001 TABLE 1 Number average molecular mass (M.sub.n) and polydispersity index (I) obtained by SEC for the alkyl acrylate-hydroxyalkyl acrylate bipolymer with different monomeric weight ratio and with 1 wt % of chain transfer agent (BHA-1 series). Weight Polydispersity ratio M.sub.n index Bipolymer (% wt/wt) (g mol.sup.−1) (I) BHA-911 90/10 17 080 1.98 BHA-821 80/20 18 061 1.67 BHA-731 70/30 18 215 1.40 BHA-641 60/40 18 950 1.35

[0071] Table 2 displays the results for the poly(alkyl acrylate-hydroxyalkyl acrylate) (R.sub.1 and R.sub.3=hydrogen, R.sub.2=n-butyl R.sub.3=2-hydroxyethyl) corresponding to the BHA-2 series.

TABLE-US-00002 TABLE 2 Number average molecular mass (M.sub.n) and polydispersity index (I) obtained by SEC for the alkyl acrylate-hydroxyalkyl acrylate bipolymer with different monomeric weight ratio and with 2 wt % of chain transfer agent (BHA-2 series). Weight Polydispersity ratio M.sub.n index Bipolymer (% wt/wt) (g mol.sup.−1) (I) BHA-912 90/10 14 210 1.81 BHA-822 80/20 13 120 1.50 BHA-732 70/30 12 870 1.38 BHA-642 60/40 11 590 1.23

[0072] Table 3 exhibits the results for the poly(alkyl acrylate-hydroxyalkyl acrylate) (R.sub.1 and R.sub.3=hydrogen, R.sub.2=n-butyl R.sub.3=2-hydroxyethyl) corresponding to the BHA-4 series.

TABLE-US-00003 TABLE 3 Number average molecular mass (M.sub.n) and polydispersity index (I) obtained by SEC for the alkyl acrylate-hydroxyalkyl acrylate bipolymer with different monomeric weight ratio and with 4 wt % of chain transfer agent (BHA-4 series). Weight Polydispersity ratio M.sub.n index Bipolymer (% wt/wt) (g mol.sup.−1) (I) BHA-914 90/10 12 045 1.76 BHA-824 80/20 10 996 1.67 BHA-734 70/30  9 860 1.29 BHA-644 60/40  8 437 1.06

BHA-1 Series

[0073] Bipolymers of high randomness and controlled molecular mass based on alkyl acrylate-hydroxyalkyl acrylate.

[0074] FT-IR. v cm.sup.−1: 3450, 2960, 2931, 2870, 1732, 1453, 1395, 1249, 1167, 1071, 1020, 946.

[0075] .sup.1H NMR δ (ppm): 4.19, 4.04, 3.80, 2.28, 1.62, 1.60, 1.38, 0.94.

[0076] .sup.13C NMR δ (ppm): 174.54, 66.51, 64.43, 60.61, 41.37, 36.27, 35.25, 34.37, 30.61, 19.10, 14.14, 13.74.

Evaluation of the Bipolymers as Dehydrating Agents in Crude Oils with Gravities from 7 to 40° API

[0077] Each one of the exemplary bipolymers was dissolved in a solvent as dichloromethane, methanol, ethanol, isopropanol, chloroform acetone, dimethyl sulfoxide, tetrahydrofuran, dioxane, benzene and its derivatives, toluene, xylene, aromatic amines, jet fuel, or naphtha, in order to prepare concentrated dissolutions of each random bipolymer, from about 3.0 to 55.0 wt %. In each case, an aliquot of the demulsifying was added at a specific concentration, comprised in the interval from about 10 to 2000 ppm, to avoid any influence of the solvent on the destabilization of the emulsion and, consequently, in amount of removed water from the assessed crude oil. Random bipolymers based on acrylic were simultaneously assessed, comparing its performance with the FDH-1 commercial dehydrating formulation, which is widely employed in the oil industry. This formulation is comprised of four ethylene oxide-propylene oxide-ethylene oxide triblock bipolymers (PEO-PPO-PEO) of different molecular mass and with a propylene oxide/ethylene oxide weight ratio (PO/EO) of 90/10 (7,750 g mol.sup.−1), 70/30 (5,330 g mol.sup.−1), 60/10 (3,050 g mol.sup.−1) and 90/10 (1,400 g mol.sup.−1).

[0078] The assessment to determine the amount of removed water was carried out by bottle test, following the procedure described in the Mexican patent document No. 386485 B [37], in the Canadian patent No. 3013494 C [36], and in the U.S. Pat. Nos. 10,793,783 B2 [35] and 10,975,185 B2 [38], where a bottle with untreated crude oil (crude oil without the demulsifying product, labeled as blank), a bottle for each random bipolymer based on alkyl acrylate-hydroxyalkyl acrylate, and a bottle for the FDH-1 commercial formulation are taken into account. An aliquot of the dissolution of random bipolymer based on alkyl acrylate-hydroxyalkyl acrylate and the FDH-1 commercial formulation, considering the dosage to assess, was added to each bottle; subsequently, the crude oil was poured into until the mark of 100 mL. Once the filling of the bottles is finished, the first read was taken without manual agitation of the bottles, which was called time zero. The bottles were then placed into a thermal controlled bath, and the breakdown of the water-in-crude oil (W/O) emulsion was regularly measured during the 5 h of assessment.

[0079] Table 4 displays the physicochemical characterization and properties of the employed crude oils on the assessment of the random bipolymers based on alkyl acrylate-hydroxyalkyl acrylate of controlled molecular mass as demulsifying agents.

TABLE-US-00004 TABLE 4 Physicochemical characterization and properties of crude oils subjected to dehydration. Property CR-1 CR-2 CR-3 CR-4 CR-5 API gravity (°) 21.0  .sub. 7.6.sup.a 13.6  37.3  15.2 Salt content 19.sup.b  42 176.sup.b    6 800.sup.b   30   >151 (lb mbb.sup.−1) Paraffins content 51.4   0.91  3.39  2.21 3.76 (wt %) Runoff temperature −24   +24    −12    <−51    −33 (° C.) Water content by 9.0 67.0  21.0  50.0  30.0 distillation (vol %) Water and 9.1 69.0  21.2  54.0  30.1 sediments (vol %) Kinematic viscosity 275.2  —.sup.c 4402    5.9 335.5.sup.d (mm.sup.2 s.sup.−1) @ 25° C. Number average 367    1375    500    214    375 molecular mass by cryoscopy (g mol.sup.−1) Saturates (wt %) 34.93 31.37  6.60 47.78 51.53 Aromatics (wt %) 32.83 33.48 30.12 38.90 13.93 Resins (wt %) 22.56 22.54 45.90 12.05 19.50 Asphaltenes (wt %)  9.52 12.53 17.33  1.19 15.04 .sup.aApparent gravity. .sup.bThe sample was diluted. .sup.cThe results are out of method. .sup.dKinematic viscosity at 40° C.

[0080] As demonstration, FIGS. 1, 3, 5, 7, 9, and 10 show the results of the water removal efficiency of the random bipolymers of controlled molecular mass based on alkyl acrylate and hydroxyalkyl acrylate, whereas FIGS. 2, 4, 6, and 8 display the bottle images and the micrographs of crude oil after the assessment.

[0081] FIG. 1 shows the demulsifying performance of the random bipolymers based on alkyl acrylate-hydroxyalkyl acrylate, synthesized with different monomeric weight ratio and 1 wt % of chain transfer agent, in the CR-1 crude oil (21.0° API) at a dosage of 1500 ppm. As can be observed, all the random bipolymers of BHA-1 series reached the total removal of emulsified water. The BHA-911 bipolymer presents the highest coalescence rate, being the first one to reach 100 vol % at 120 min, despite having started the breakdown of the emulsion at 40 min. On the other hand, the BHA-821 bipolymer showed a lower coalescence rate than the BHA-911 bipolymer; however, it achieved the total removal at 180 min followed by the BHA-731 bipolymer, which, despite having initiated the breakdown at 120 min and presented the lowest coalescence rate during the first 180 min of the assessment, reached the total removal at 240 min. Finally, although the BHA-641 bipolymer presented the best performance as emulsion breaker, managing to destabilize it at 25 min of the assessment; it presented a lower coalescence rate, being the last random bipolymer to achieve 100 vol % of emulsified water removal. It is worth highlighting that all random bipolymers of BHA-1 series outperform the FDH-1 commercial formulation, which achieved a maximum removal of 88 vol % at 180 min of the assessment.

[0082] FIG. 2 shows the bottles images and micrographs of the CR-1 crude oil after the treatment with the BHA-911 bipolymer—first one on reaching 100 vol % of removed water—and with the FDH-1 commercial formulation—88 vol %—, which were compared with the crude oil without demulsifying agent (blank). Firstly, in the blank bottle was not observed the presence of removed water, therefore, the water-in-crude oil emulsion is highly stable under the assessment conditions. For its part, in the image of the bottle of crude oil treated with the BHA-911 bipolymer is observed a removed water—crude oil interface completely homogeneous compared with the crude oil treated with the FDH-1 commercial formulation. Additionally, a greater clarification of the separated water is notable when the BHA-911 is used (which is similar to the rest of bipolymers of the BHA-1 series, although the bottles are not shown in FIG. 2) in comparison with the clarification of removed water by the FDH-1 commercial formulation. On the other hand, the micrograph of the untreated crude oil (blank) displays an emulsion with low polydispersity and with a droplet size ranging from about 0.1 to 0.7 μm, which can be related with the amount of asphaltenes present in the crude oil, because they can stabilize smaller water droplets. Regarding the micrograph of the crude oil dosed with the BHA-911 bipolymer, only the presence of organic agglomerates—possibly paraffins—is observed; for this reason, the total removal of the emulsified water is confirmed. Finally, the micrograph corresponding to the sample of crude oil treated with the FDH-1 commercial formulation presents a remnant emulsion with a smaller distribution of water droplet size from 0.3 to 0.6 μm, that is, a system with a lower polydispersity than that present in the blank sample.

[0083] FIG. 3 displays the performance of random bipolymers with a monomeric weight ratio of alkyl acrylate/hydroxyalkyl acrylate of 80/20% wt/wt, synthesized with 1, 2, and 4 wt % of chain transfer agent—BHA-821, BHA-822, and BHA-824, respectively—, assessed in the CR-2 crude oil (7.6° API) at a dosage of 1500 ppm. It can be observed that the BHA-822 bipolymer with M.sub.n=13 120 g mol.sup.−1—medium chain length—shows the highest coalescence rate throughout the evaluation, being the only demulsifying agent capable of removing all the emulsified water. Although this crude oil presents the second highest content of asphaltenes, in addition to a high content of saturates and aromatics, the BHA-822 bipolymer is capable of destabilizing more efficiently the layer of paraffins and asphaltenes that surrounds the water droplets and induce their coalescence. On the other hand, the BHA-824 acrylic bipolymer with M.sub.n=10 996 g mol.sup.−1—shortest chain length—displayed a slightly lower coalescence rate than the BHA-822 bipolymer; however, at 90 min reached its maximal removal efficiency of 91 vol %. It should be noted that, although the BHA-821 bipolymer with M.sub.n=18 061 g mol.sup.−1—long chain length—showed the lowest coalescence rate during the first hour of assessment, at 90 min, it had already surpassed the FDH-1 formulation, reaching a maximum removal of 94 vol %. Finally, the FDH-1 commercial formulation exhibited a coalescence rate similar to that of the BHA-821 bipolymer during the first 20 min; nevertheless, at the end of the assessment it removed 1 vol % less of emulsified water than the bipolymer. In this sense, for the CR2-crude oil, it can be clearly appreciated that, together with an appropriate monomer weight composition, the number average molecular mass of the random bipolymer based on acrylic plays an important role in the efficiency for the removal of emulsified water. Firstly, a bipolymer of high number average molecular mass—longest chain—, presents a greater difficulty to penetrate the layer of paraffins and asphaltenes that surround the water droplets, because of a greater hindrance steric, therefore, the performance to induce the droplet coalescence decreases. On the contrary, a random bipolymer with a number average molecular mass overly low—shortest chain length—, although it can penetrate the layer of paraffins and asphaltenes, due to its lower molecular volume, it is not capable of causing the complete destabilization of the layer of paraffins and asphaltenes, which is reflected in a lower removal efficiency. Finally, a random bipolymer with a suitable number average molecular mass for the crude oil to be treated, promotes the destabilization of the layers of paraffins and asphaltenes with greater efficiency, for this reason, a greater coalescence of the water droplets is presented, and therefore, a greater amount of removed water.

[0084] FIG. 4 displays the well-defined interface generated by the BHA-822 bipolymer, which can be contrasted with that obtained with the FDH-1 commercial formulation, where it is clear that there is still residual emulsion. Regarding the optical micrographs, the untreated crude oil sample—without demulsifying agent—presents a high polydispersity in droplet size from about 0.1 to 2.5 μm. It is notable that the droplet size present in this crude oil compared with that observed in the CR-1 crude oil is due to the greater amount of asphaltenes presents in the CR-2 crude oil, which allows stabilizing larger water droplets. In the micrograph of the crude oil sample dosed with the BHA-822 bipolymer, the total removal of emulsified water is confirmed, showing the presence of organic matter, possibly dispersed asphaltenic sludges. In the case of crude oil treated with the FDH-1 commercial formulation, the micrograph allows observing droplets of up to 1.9 μm. Normally, a good demulsifier is capable of removing this droplet size, as happens when the BHA-822 bipolymer is dosed, therefore, it is notorious the lower performance of the FDH-1 commercial formulation as coalescer. Lastly, it is visible the difference in the removed water-crude oil interface obtained with the BHA-822 random bipolymer compared with FDH-1 commercial formulation, where the interface is non-homogeneous, mainly because of the presence of emulsified water droplets in this area.

[0085] FIG. 5 depicts the demulsifying performance of the random bipolymers based on alkyl acrylate—hydroxyalkyl acrylate, synthesized with 1 wt % of chain transfer agent (BHA-1 series bipolymers) and the FDH-1 commercial formulation, assessed in the CR-3 crude oil (13.6° API) at a dosage of 1000 ppm. All bipolymers of the BHA-1 series could achieve the total removal of the emulsified water. In this sense, the BHA-821 bipolymer showed the highest coalescence rate, reaching 100 vol % at 90 min, followed by the BHA-641 and BHA-911 bipolymers at 120 min. It is important to mention that even though this last bipolymer induced the emulsion breakdown up to 40 min, later, this exhibited an excellent coalescence rate. The BHA-731 bipolymer presented the lowest coalescence rate of all random bipolymers, reaching 100 vol % up to 180 min of the assessment. In contrast, the FDH-1 commercial formulation displayed a low coalescence rate throughout the evaluation, stagnating at a maximal removal of 85 vol % at 120 min.

[0086] FIG. 6 shows the bottle images and micrographs after the assessment with the demulsifying agents. In first instance, it is not observed the presence of removed water in the bottle of untreated crude oil (without demulsifying agent (blank)); therefore, the colloidal system is stable under the assessment conditions. Regarding the blank's micrograph, it is appreciated a system with low polydispersity, where the droplet size is found around of 0.1 μm. In addition to this, it is perceptible the presence of a salt crystal, with an approximate width of 2.9 μm. On the other hand, the absence of remaining emulsion is visible in the micrograph of crude oil after the treatment with the BHA-821 random bipolymer, although the presence of paraffin agglomerates is notable. In the case of the crude oil treated with the FDH-1 commercial formulation, a small amount of emulsified water can be observed, in a low polydispersity system with a droplet size around of 0.2 μm. Finally, despite that both the BHA-821 bipolymer and the FDH-1 commercial formulation generate a well-defined interface, it is possible to appreciate that the clarification of the removed water by the BHA-821 bipolymer—as well as that of the BHA-911, BHA-731, and BHA-641 bipolymers, although these are not shown in the FIG. 6—, is markedly superior to that of the FDH-1 commercial formulation.

[0087] The bipolymers based on alkyl acrylate-hydroxyalkyl acrylate synthesized with 2 wt % (BHA-2 series bipolymer) and 4 wt % (BHA-4 series bipolymer) of chain transfer agent were assessed in the CR4 light crude oil (37.3° API) at a dosage of 250 ppm (FIGS. 7 and 8, respectively). As can be appreciated in the FIG. 7, the FDH-1 formulation presented the highest coalescence rate during the first 60 min—higher amount of removed water—; however, at 90 min of assessment, the performance of the BHA-822 and BHA-912 bipolymers were superior, reaching a final removal of 100 vol %—120 min—and 98 vol %—180 min—, respectively. On the other hand, even though the BHA-732 and BHA-642 bipolymers showed low coalescence rates tan the FDH-1 commercial formulation during the first 90 min of assessment, these achieved the total removal of emulsified water at 240 min, surpassing the FDH-1 commercial formulation, which barely reached to remove 74 vol % of the emulsified water.

[0088] FIG. 8 shows the performances as demulsifying agents of the random bipolymers based on alkyl acrylate—hydroxyalkyl acrylate synthesized with 4 wt % of chain transfer agent (BHA-4 series bipolymer), assessed in the CR-4 light crude oil (37.3° API) at a dosage of 250 ppm. As can be appreciated, the BHA-824 and BHA-914 bipolymers displayed the highest coalescence rate, reaching the total removal of the emulsified water at 120 and 180 min, respectively. It should be noted that the BHA-734 bipolymer presented a good performance as coalescer, reaching a maximal removal of 98 vol %. These three acrylic bipolymers notably exceeded the efficiency of the FDH-1 commercial formulation, which barely removed 74 vol %, as made by the BHA-644 bipolymer.

[0089] The bottle images and the micrographs of FIG. 9 correspond to the untreated crude oil (without demulsifying agent (blank)) the crude oil dosed with the BHA-822 and BHA-824 random bipolymers—the first ones to remove all the emulsified water—, respectively; and finally, the crude oil dosed with the FDH-1 commercial formulation. As can be observed, the BHA-822 and BHA-824 acrylic bipolymers, as well as the FDH-1 commercial formulation bring about a removed water-crude oil interface completely homogeneous and well-defined. On the other hand, the clarification of the removed water by the BHA-822 and BHA-824 random bipolymers based on alkyl acrylate-hydroxyalkyl acrylate—including the rest of the random bipolymers of the BHA-2 and BHA-4 series that are not shown in the FIG. 9—, is slightly superior to the clarification of the removed water by the FDH-1 commercial formulation.

[0090] Regarding the micrographs, the crude oil without demulsifying agent presents a highly polydisperse emulsion with droplet size between about 0.01 and 0.60 μm. On the other hand, the treated crude oil samples with the BHA-822 and BHA-824 bipolymers do not present remanent emulsion; organic aggregates are only observed, possibly asphaltenes. In the case of the micrograph of the treated crude oil with the FDH-1 commercial formulation is notorious the presence of remaining emulsion displaying a low polydispersity system with a droplet size between 0.1 and 0.7 μm. It should be highlighted that in this last one, an organic matter film can be seen surrounding the droplets, which indicates that the commercial formulation of polyethers is not capable of displacing this barrier to allow the coalescence of the water droplets.

[0091] FIG. 10 displays the demulsifying performance of the BHA-822 random acrylic bipolymer compares with the FDH-1 commercial formulation assessed in the CR-5 heavy crude oil (15.2° API) at pH=7 and pH=2, evaluating a dosage of 1500 ppm. It can be observed that under non-acid conditions—pH=7—, until the 60 min of assessment, the BHA-822 bipolymer exhibits a higher coalescence rate in comparison with the acid conditions—pH=2—. This difference is mainly due to the fact that in acid conditions, the asphaltene layer is agglomerated with greater force, which forms a barrier that is more difficult to destabilize. From 90 min to the end of the evaluation, the coalescence rate is similar in both systems, being capable the BHA-822 bipolymer of completely removing the emulsified water 300 min of the test. In contrast, besides that the FDH-1 formulation only removes 56 vol % of the emulsified water under non-acid conditions, the performance as demulsifier decreases to 23% at pH=2. Thus, the high chemical stability of the random alkyl acrylate-hydroxyalkyl acrylate bipolymers of the present disclosure are demonstrated, in addition to their excellent performance in the water removal. While the foregoing disclosure describes the inventions in some detail by way of example and illustration for purposes of clarity and understanding, this disclosure including the examples, descriptions, and embodiments described herein are for illustrative purposes, are intended to be exemplary, and should not be construed as limiting the inventions. It will be clear to one skilled in the art that various modifications or changes to the examples, descriptions, and embodiments described herein can be made and are to be included within the spirit and purview of this disclosure and the appended claims. Further, one of skill in the art will recognize a number of equivalent methods and procedure to those described herein. All such equivalents are to be understood to be within the scope of the present disclosure and are covered by the appended claims.

[0092] The disclosures of all publications, patent applications, patents, or other documents mentioned herein are expressly incorporated by reference in their entirety for all purposes to the same extent as if each such individual publication, patent, patent application or other document were individually specifically indicated to be incorporated by reference herein in its entirety for all purposes and were set forth in its entirety herein. In case of conflict, the present specification, including specified terms, will control.

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