Demulsifiers containing alkoxylated castor oil

Abstract

A demulsifier may contain a surfactant that meets Formula 4 or 5 Wherein · Each R1 is independently a fatty organic moiety; · Each (R2-O)a independently represents a lipophilic poly(alkylene oxide block), in which each (R2-O) independently represents alkylene oxide repeating unit in the lipophilic poly(alkylene oxide) block, and each "a" independently represents the number of repeating units in the lipophilic poly(alkylene oxide) block; · (R3-O)b independently represents a hydrophilic poly(alkylene oxide block), in which each (R3-O) independently represents alkylene oxide repeating units in the hydrophilic poly(alkylene oxide) block, and "b" represents the number of repeating units in the hydrophilic poly(alkylene oxide) block; and · each R4 independently represents a hydrogen or an alkyl moiety, and other variants made by alkoxylating castor oil and related tri-ester compounds with blocks of lipophilic poly(alkylene oxide) followed by blocks of hydrophilic poly(alkylene oxide).

Description

[0001] DEMULSIFIERS CONTAINING ALKOXYLATED CASTOR OIL FIELD This invention relates to the field of demulsifiers. INTRODUCTION Petrochemical processes often require that emulsions be broken up. For example, salts are removed from organic liquids such as crude oil by (1) mixing the organic liquid with water to dissolve the salts, (2) allowing the organic-phase to separate from the aqueous phase; and (3) decanting to separate the two phases. In crude oil processing, this step is called “desalting.” However, polar impurities in the organic liquid can form a film on water droplets in the oil and encourage the formation of a water-in-oil emulsion, which prevents the aqueous and organic phases from separating. Crude oil frequently contains such polar impurities. To prevent forming the emulsion, demulsifier is added to the mixture to break the emulsion and allow the phases to separate. Demulsifiers contain surfactants that can displace polar components in the film around the water droplets in the emulsion. Breaking up the film breaks up the emulsion, so that water droplets coalesce and separate from the organic phase. In many demulsifiers, the surfactant is mixed with a solvent. Common solvents include benzene, toluene, xylene, short-chain alcohols, and heavy aromatic naphtha. Some demulsifiers also contain flocculant. Flocculants encourage water droplets to coalesce. The effectiveness of individual demulsifiers varies depending on the composition of the organic liquid, the impurities in it, and the conditions under which demulsification occurs. In the oil desalting process, the selection and dosing of demulsifiers for each individual crude oil source is set based on specific tests for that source. The typical test is the “bottle test.” Several bottles of the crude oil are mixed with water and different demulsifiers in different doses. The bottles are observed to see which demulsifier and dosage works best based on water-drop, which is the amount and speed with which water separates from the emulsion. The selection and dosage of demulsifier is decided based on these observations. There is a need for new demulsifier surfactants that may be used in lower doses and may be more effective than current demulsifiers for at least some organic compositions. SUMMARY One aspect of this invention is a process to make a surfactant comprising the steps of: (a) Providing a tri-ester compound that comprises three fatty acids having pendant hydroxyl groups linked to a triol by ester linkages between the acid groups of the fatty acids and the hydroxyl groups of the triol; (b) Alkoxylating the tri-ester compound in step (a) by reacting the tri-ester compound with alkylene oxide monomers suitable to form blocks of lipophilic poly(alkylene oxide) polymer, in the presence of a base; and (c) Further alkoxylating the product of step (b) by reacting the product of step (b) with alkylene oxide monomers suitable to form blocks of hydrophilic poly(alkylene oxide) polymer, in the presence of a base. A second aspect of this invention is a surfactant made by the process of this invention. A third aspect of this invention is a process to prevent or break a water-in-oil emulsion caused by the mixing of water and oil, comprising the step of contacting the water, oil or emulsion with a demulsifier that contains a surfactant as described in the second aspect of the invention. The surfactants of this invention are useful in a demulsifier that is effective for some emulsions. DETAILED DESCRIPTION This invention relates to a surfactant and a process to make it. The starting material for the process is a tri-ester compound that has three ester linkages. Each ester linkage links the remnant of a triol compound with the remnant of a fatty acid that has pendant hydroxyl groups. Examples of the tri-ester compound are illustrated by Formula 1: organic moiety. Pendant hydroxyl groups on the fatty organic compound provide reaction sites to graft poly(alkylene oxide) polymer blocks. In some embodiments, each fatty organic moiety (R1) is independently hydrocarbyl. In some embodiments, each fatty organic moiety is aliphatic. In some embodiments, one or more of the fatty organic moieties is alkyl. In some embodiments, each fatty organic moiety is independently alkyl. In some embodiments, one or more of the fatty organic moieties is mono-unsaturated. In some embodiments, each fatty organic moiety is independently mono-unsaturated. In some embodiments, one or more of the fatty organic moieties is poly-unsaturated. In some embodiments, one or more of the fatty organic moieties are aliphatic-aryl and contain at least a 6 carbon aliphatic chain. In some embodiments, each fatty organic moiety (R1) independently contains on average at least 8 carbon atoms or at least 10 carbon atoms or at least 12 carbon atoms or at least 14 carbon atoms or at least 16 carbon atoms or at least 17 carbon atoms or at least 18 carbon atoms. In some embodiments, each fatty organic moiety independently contains on average at most 24 carbon atoms or at most 22 carbon atoms or at most 20 carbon atoms or at most 19 carbon atoms or at most 18 carbon atoms. In some embodiments, the fatty organic moieties (R1) in each tri-ester compound contain on average in aggregate at least 24 carbon atoms or at least 30 carbon atoms or at least 36 carbon atoms or at least 42 carbon atoms or at least 48 carbon atoms or at least 52 carbon atoms or at least 56 carbon atoms or at least 58 carbon atoms. In some embodiments, the fatty organic moieties (R1) in each tri-ester compound contain on average in aggregate at most 100 carbon atoms or at most 30 carbon atoms or at most 80 carbon atoms or at most 75 carbon atoms or at most 70 carbon atoms or at most 68 carbon atoms or at most 66 carbon atoms or at most 64 carbon atoms. In some embodiments, each fatty organic moiety (R1) independently has a chain of at least 6 carbon atoms between the ester group and the hydroxyl group (not counting the carbon atom in the carboxylate group) or at least 8 carbon atoms or at least 10 carbon atoms or at least 11 carbon atoms. In some embodiments, each fatty organic moiety (R1) independently has a chain of at most 20 carbon atoms between the ester group and the hydroxyl group (not counting the carbon atom in the carboxylate group) or at most 18 carbon atoms or at most 16 carbon atoms or at most 14 carbon atoms or at most 12 carbon atoms. In some embodiments, the hydroxyl group pendant from a fatty organic moiety is a primary hydroxyl group in the omega position (at the terminal position with respect to the carboxylic acid group). In some embodiments, the hydroxyl group pendant from a fatty organic moiety is a secondary hydroxyl group. In some embodiments, the hydroxyl group pendant from a fatty organic moiety is a tertiary hydroxyl group. Each fatty ester group (-O-CO-R1-OH) can be expressed as a derivative ester from a fatty acid having one or more pendant hydroxyl groups. Examples of known fatty acids having pendant hydroxyl groups include ricolenic acid and fatty omega hydroxy acids such as 8-hydroxyoctanoic acid, 9- hydroxynonanoic acid, 10-hydroxydecanoic acid, sabinic acid (12-hydroxydodecanoic acid), juniperic acid (16-hydroxyhexadecanoic acid), and ω-hydroxystearic acid. In a convenient embodiment, the starting material provided in step (a) is castor oil, whose major component is a tri-ester of glycerol with three ricolenic acids. Each ricolenic acid contains an 18-carbon aliphatic chain that is monounsaturated and has 11 carbon atoms between the carboxylate group and the hydroxyl group (not counting the carbon atom in the carboxylate group). The hydroxyl groups in castor oil are secondary hydroxyl groups. In steps (b) and (c), the tri-ester compound is alkoxylated by known reactions to add blocks of lipophilic and hydrophilic poly(alkylene oxide). (Poly(alkylene oxide) polymers are also commonly known as poly(alkylene glycol) polymers, such as polyethylene glycol or polypropylene glycol.) In summary, the tri-ester compound is contacted with a strong base such as alkali metal hydroxide. Then, the compound is contacted with alkylene oxide monomers, such as ethylene oxide, propylene oxide, and / or butylene oxide. To make the block copolymers, a first polymerization (step (b)) is performed by adding a first mix of alkylene monomers to make the lipophilic block and, after the first mix of monomers is consumed, adding a second mix of monomers (step (c)) to make the hydrophilic block. Common alkylene oxide monomers include ethylene oxide, propylene oxide, and butylene oxide. All three monomers are commercially available. Alkylene oxide monomers produce alkylene oxide repeating units which are shown in Formula 2: wherein R5is hydrogen or an group. oxide monomers produce ethylene oxide repeating units, which are shown in Formula 2 wherein R5is hydrogen. Ethylene oxide repeating units are hydrophilic. Propylene oxide monomers produce propylene oxide repeating units, which are shown in Formula 2 wherein R5is a methyl group. Butylene oxide monomers produce butylene oxide repeating units, which are shown in Formula 2 wherein R5is an ethyl group. Lipophilic poly(alkylene oxide) polymer is typically derived primarily from propylene oxide and / or butylene oxide monomers and contains repeating units that are primarily propylene oxide or butylene oxide repeating units or a mixture of propylene oxide and butylene oxide repeating units. “Primarily” means that more than 50 mole percent of repeating units in the lipophilic poly(alkylene oxide) block are propylene oxide or butylene oxide repeating units. In some embodiments, at least 60 mole percent of repeating units are propylene oxide or butylene oxide repeating units, or at least 70 mole percent or at least 80 mole percent or at least 90 mole percent or at least 95 mole percent or 100 mole percent. In some embodiments, repeating units that are not propylene oxide or butylene oxide repeating units are primarily ethylene oxide repeating units. Hydrophilic poly(alkylene oxide) polymer is typically derived from at least 80 mole percent ethylene oxide monomer and 80 mole percent of repeating units are ethylene oxide repeating units. In some embodiments, at least 85 mole percent of repeating units are ethylene oxide repeating units, or at least 90 mole percent or at least 95 mole percent or 100 mole percent. In some embodiments, repeating units that are not ethylene oxide repeating units are primarily propylene oxide or butylene oxide repeating units.

[0002] In some cases, blocks of poly(alkylene oxide) graft onto each pendant hydroxyl group in the tri- ester, and so a component of the surfactant is represented by Formula 4: • Each R1is a fatty organic moiety as previously described; • Each (R2-O)aindependently represents a lipophilic poly(alkylene oxide) block, in which each (R2-O) independently represents alkylene oxide repeating units in the lipophilic poly(alkylene oxide) block, and each “a” independently represents the number of repeating units in the lipophilic poly(alkylene oxide) blocks; • Each (R3-O)b independently represents a hydrophilic poly(alkylene oxide) block, in which each (R3-O) independently represents alkylene oxide repeating units in a hydrophilic poly(alkylene oxide) block, and each “b” independently represents a number of repeating units in the hydrophilic poly(alkylene oxide) blocks; and • Each R4is independently hydrogen or an alkyl moiety that terminates the poly (alkylene oxide) chain. However, other reactions are also possible, and so the surfactant may optionally comprise a mixture of many different moieties pendant from the triol at the center of the fatty tri-ester compound. Components in the surfactant may include compounds represented by Formula 5: represents a moiety pendant from the triol moiety. In some embodiments, a fatty acid portion of the tri-ester does not react at all, and so a pendant Z moiety may be represented by Formula 5a, wherein R1has the meaning previously described. nt hydroxyl groups in the fatty acid portion of the tri-ester are alkoxylated as described before, and so a pendant Z moiety may be represented by Formula 5b, wherein R1, R2, R3, R4, a and b have the meaning previously described. In some embodiments, the ester linkage that binds a fatty acid to the triol is hydrolyzed by the aqueous base used in the reaction. This reaction forms a pendant hydroxyl group on the triol, so that a pendant Z moiety is a hydrogen atom. In some embodiments, the pendant hydroxyl group that is formed by hydrolysis as described above may become alkoxylated in step (b) and / or (c), so that a pendant Z moiety consists essentially of blocks of poly(alkylene oxide) and may be represented by Formula 5c, wherein R2, R3, R4, a and b have the meaning previously described. This hydrolysis reaction also forms a free fatty acid with pendant hydroxyl groups. In some embodiments, the hydroxyl group on the free fatty acid becomes alkoxylated to form a compound represented by Formula 6, which remains as a component of the surfactant. some acid or an alkoxylated free fatty acid can form a new ester linkage with a pendant poly(alkylene oxide) block illustrated in Formula (5c), so that a pendant Z moiety is represented by Formula 5(d) or 5(e), wherein R1, R2, R3, R4, a and b have the meaning previously described. The surfactants of this invention may comprise components that contain any or all of the above described species of Z. In some embodiments, the surfactant contains in aggregate at least 30 weight percent of the surfactant compounds illustrated in Formula 4 (based on organic components and excluding water), or at least 40 weight percent, or at least 50 weight percent or at least 60 weight percent or at least 70 weight percent or at least 80 weight percent or at least 90 weight percent or 100 weight percent. In some embodiments, the surfactant contains at most 70 weight percent of other organic components (based on organic components and excluding water) or at most 60 weight percent or at most 50 weight percent or at most 40 weight percent or at most 30 weight percent or at most 20 weight percent or at most 10 weight percent or 0 weight percent. In some embodiments, each surfactant molecule contains on average at least 5 repeating units of the lipophilic poly(alkylene oxide) polymer, or at least 10 repeating units or at least 15 repeating units or at least 20 repeating units or at least 30 repeating units or at least 40 repeating units or at least 50 repeating units or at least 60 repeating units. In some embodiments, each surfactant molecule contains on average at most 120 repeating units of the lipophilic poly(alkylene oxide) polymer, or at most 110 repeating units or at most 100 repeating units or at most 90 repeating units or at most 80 repeating units. This ratio reflects the molar ratio of alkylene oxide monomers to the tri-ester compound in step (b). In some embodiments, each surfactant molecule contains on average at least 25 repeating units of the hydrophilic poly(alkylene oxide) polymer, or at least 35 repeating units or at least 45 repeating units or at least 55 repeating units or at least 65 repeating units or at least 75 repeating units or at least 85 repeating units or at least 95 repeating units. In some embodiments, each surfactant molecule contains on average at most 150 repeating units of the hydrophilic poly(alkylene oxide) polymer or at most 140 repeating units or at most 130 repeating units or at most 120 repeating units or at most 110 repeating units or at most 105 repeating units. This ratio reflects the molar ratio of alkylene oxide monomers to the tri- ester compound in step (c). The average lengths of the lipophilic and hydrophilic polymer blocks and the molecular weights of surfactant can be adjusted by adjusting the relative weights of the tri-ester and the lipophilic monomer mixture in the first polymerization step and the hydrophilic monomer mixture in the second polymerization step. In some embodiments, the molar ratio of ethylene oxide repeating units to other alkylene oxide repeating units in the surfactant is on average at least 0.5 or at least 0.6 or at least 0.7 or at least 0.8 or at least 0.9 or at least 1.0 or at least 1.1 or at least 1.2 at least 1.3. In some embodiments, the molar ratio of ethylene oxide repeating units to other alkylene oxide repeating units in the surfactant is on average at most 20 or at most 18 or at most 16 or at most 14 or at most 12 or at most 10 or at most 8 or at most 6 or at most 4 or at most 3 or at most 2. In some embodiments, each molecule of the surfactant contains on average at least 2 alkylene oxide repeating units or at least 10 alkylene oxide repeating units or at least 20 alkylene oxide repeating units or at least 30 alkylene oxide repeating units or at least 40 alkylene oxide repeating units or at least 45 or at least 50 or at least 55 or at least 60 or at least 65 or at least 70 or at least 75 or at least 80 or at least 85 or at least 90. In some embodiments, each molecule of the surfactant contains on average at most 200 alkylene oxide repeating units or at most 180 alkylene oxide repeating units or at most 160 or at most 140 or at most 120 or at most 100 or at most 95 or at most 92 or at most 90 or at most 85 or at most 80 This ratio reflects the molar ratio of alkylene oxide monomers used in steps (b) and (c) combined, to the tri-ester compound in Formula 1. In some embodiments, the surfactant has a number average molecular weight (Mn) of at least 2000 g / mol or at least 2500 g / mol or at least 2800 g / mol or at least 3000 g / mol or at least 3200 g / mol or at least 3400 g / mol or at least 3600 g / mol or at least 3800 g / mol. (All molecular weights are measured by GPC measurement calibrated using polystyrene standards, as described in the Test Methods.) In some embodiments, the surfactant has a number average molecular weight (Mn) of at most 5000 g / mol or at most 4800 g / mol or at most 4600 g / mol or at most 4400 g / mol or at most 4200 g / mol or at 4000 g / mol. In some embodiments, the surfactant has a weight average molecular weight (Mw) of at least 2000 g / mol or at least 2500 g / mol or at least 3000 g / mol or at least 3500 g / mol or at least 3800 g / mol or at least 4000 g / mol or at least 4200 g / mol or at least 4400 g / mol or at least 4600 g / mol or at least 4800 g / mol or at least 5000 g / mol. In some embodiments, the surfactant has a weight average molecular weight (Mw) of at most 10,000 g / mol or at most 9000 g / mol or at most 8000 g / mol or at most 7500 g / mol or at most 7000 g / mol or at most 6500 g / mol or at most 6000 g / mol. In some embodiments, the surfactant has a polydispersity index (Mw / Mn) of at least 1.1 or at least 1.2 or at least 1.3 or least 1.4. In some embodiments, the surfactant has a polydispersity index (Mw / Mn) of at most 2.0 or at most 1.8 or at most 1.7 or at most 1.6 or at most 1.5. In some embodiments, the surfactant has a relative solubility number (RSN) of at least 8 or at least 8.5 or at least 9 or at least 9.5 or at least 10 or at least 10.5 or at least 11. In some embodiments, the surfactant has a relative solubility number (RSN) of at most 20 or at most 18 or at most 16 or at most 15 or at most 14 or at most 13 or at most 12. The relative solubility number of the surfactants can be adjusted by adjusting the lengths of lipophilic and hydrophilic chains. The surfactant may be used in a demulsifier to prevent or break emulsions. In some embodiments, the demulsifier consists essentially of the surfactant. In some embodiments, the demulsifier contains the surfactant and a solvent. The solvent may reduce the viscosity of the surfactant to render it pumpable, and the solvent may make it easier to control the dosage of surfactant at low concentrations. In some embodiments, the solvent is organic. Examples of suitable organic solvents include toluene, liquid petroleum distillates and liquid alkanols. In some embodiments, the demulsifier contains at least 15 weight percent surfactant or at least 20 weight percent or at least 30 weight percent or at least 40 weight percent or at least 50 weight percent. In some embodiments, the demulsifier contains 100 weight percent surfactant or at most 90 weight percent or at most 80 weight percent or at most 70 weight percent or at most 60 weight percent or at most 50 weight percent or at most 30 weight percent or at most 20 weight percent. In some embodiments, the demulsifier contains from 20 to 50 weight percent surfactant and from 50 to 80 weight percent solvent. In some embodiments, the demulsifier may contain other surfactants, in addition to the surfactants of this invention. In some embodiments, the surfactants of this invention make up at least 20 weight percent of surfactants in the demulsifier, or at least 30 weight percent or at least 40 weight percent or at least 50 weight percent or at least 60 weight percent or at least 70 weight percent or at least 80 weight percent or at least 90 weight percent or 100 weight percent. In some embodiments, the demulsifier is added to an existing emulsion. In some embodiments, the emulsion is an oil-in-water emulsion. In some embodiments, the emulsion is a water-in-oil emulsion. In some embodiments, the demulsifier is added to water that will be mixed with oil, in order to prevent the water and oil from forming emulsions. In some embodiments, the demulsifier is added to oil that will be mixed with water in order to prevent the water and oil from forming emulsions. In some embodiments, the oil is crude oil, and the crude oil is being mixed with water as part of a desalting process. In some embodiments, the oil is crude oil, and the crude oil already contains emulsified water. In some embodiments, the crude oil is heavy crude oil. The optimum quantity of demulsifier may vary depending on the contents of the water and oil that are mixed together. In crude oil desalting, it is common to test samples of oil from different sources and select a demulsifier and its dosage based on the tests. For example, samples of emulsion can be tested using bottle tests as described below with different selections and dosages of demulsifier to see which combination works best. In some embodiments, the weight ratio of surfactant to oil (dosage) is at least 1 ppm or at least 10 ppm or at least 25 ppm or at least 50 ppm or at least 60 ppm or at least 70 ppm or at least 80 ppm or at least 90 ppm or at least 100 ppm. In some embodiments, the weight ratio of surfactant to oil is at most 10,000 ppm or at most 5000 ppm or at most 2000 ppm or at most 1000 ppm or at most 500 ppm or at most 400 ppm or at most 300 ppm or at most 200 ppm or at most 180 ppm or at most 160 ppm or at most 140 ppm. In some embodiments, demulsifiers of this invention will cause more than 10 percent of water in an emulsion to drop out from the emulsion (“water drop”) within 20 minutes in a bottle test as described in the Test Methods, or at least 15 percent or at least 20 percent or at least 25 percent or at least 30 percent or at least 35 percent or at least 40 percent or at least 45 percent or at least 50 percent or at least 55 percent or at least 60 percent or at least 70 percent. There is no maximum desired limit for water drop; the practical limit is 100 percent, but in some cases, a water drop of more than 80 percent within 20 minutes or more than 70 percent within 20 minutes is unnecessary. Some examples of the invention are illustrated by the following examples. Test Methods Unless stated otherwise, measurements listed in this application are made using the following test methods: Molecular Weight and Polydispersity Index (PDI) Molecular weights are determined using gel permeation chromatography (GPC). • The GPC instrument is a 1260 Infinity II LC system from Agilent, equipped with one 7.5 mm × 50 mm, 3 µm guard column from PLgel and with two 7.5 mm × 50 mm, 3 µm Mixed E columns from PLgel. The columns are maintained at 35°C. • The GPC instrument is calibrated using Agilent PS-1 and PS-2 polystyrene standards. • The samples are prepared as 1.0 mg / mL solutions in tetrahydrofuran (THF) and filtered using an Acrodisc CR 13 mm syringe filter with a 0.2 µm RTFE membrane. The samples are eluted at a flowrate of 1.77 mL / min and detected using the refractive index detector (RID). Bottle Demulsification Test A 100 mL sample of water-in-oil emulsion containing heavy crude oil from Sterling Chemicals Ltd. is weighed and added into a bottle, and the bottle is set in a water bath at 50℃. Demulsifier is diluted to a concentration of 10 weight percent in isopropanol. After the emulsion in the sample bottle reaches the desired temperature, a quantity of the demulsifier solution is added to achieve the concentration of demulsifier shown in Table 2. The bottle is shaken using a shaker table, and then submerged in the water bath at 50℃. The volume of separated water (water drop) is observed and recorded at intervals of 0, 5, 10, 15, 20, 30, 40 and 60 minutes. Similarly, observations of the interface and water quality were also taken, whenever possible. Measurement of Relative Solubility Number (RSN) A clear solvent mix is made that contains 97.4% ethylene glycol dimethyl ether (EGDE) and 2.6% toluene by volume. About 0.1 g of the demulsifier is added into an 8-mL vial, and about 3 mL of the solvent mixture is added. After thorough mixing using a magnetic stir bar on a stir plate, the mixture is titrated with deionized (DI) water using a multi-channel syringe pump. The titration end point is reached when the mixture becomes visibly cloudy. RSN is calculated by using the equation: RSN = (volume of water at titration end point) / (volume of EGDE / toluene solvent) × 30. Examples The following examples illustrate specific embodiments of the invention, but do not limit the broadest scope of the invention. The materials in Table 1 are used for the Examples: Table 1 Name Source Castor Oil Sigma Aldrich l i l h i f Preparation of Alkoxylated Castor Oil The following procedure is used to make alkoxylated castor oil samples as shown in Table 2, IE1 to IE5. A glass reactor cell with a volume of 6 mL is equipped with removable polyether ether ketone (PEEK) paddles used for mechanical stirring and with nitrogen, ethylene oxide (EO), and propylene oxide (PO) feed lines. The cell is housed inside a nitrogen-purged glovebox. A starter is made by adding KOH (1 wt%) to castor oil as a 40% water solution, and water is removed by distilling azeotropically with toluene. The starter, after toluene / water removal, is viscous at room temperature. A portion of the starter is added to the cell, as shown in Table 1, and the cell is sealed. The contents are stirred at 600 RPM and the cell is blanketed with nitrogen for the remainder of the reaction. A calculated amount of propylene oxide is added to the cell as shown in Table 2. The temperature is increased to 120°C, and reaction mixture is stirred for 30 hours after reaching the process temperature. After the pressure in the cell levels off, indicating that propylene oxide has completed polymerization, the cell is cooled, vented and purged with nitrogen to remove residual propylene oxide. A calculated amount of EO is introduced into the cell at 60°C. The temperature is increased to 130℃ and the mixture is stirred for 6 hours. After the pressure in the cell levels off, indicating that ethylene oxide has completed polymerization, the cell is cooled, vented and purged with nitrogen to remove residual ethylene oxide. Samples of the product are analyzed by NMR spectroscopy and GPC. NMR analysis confirms that the sample contains castor oil with blocks of poly(propylene oxide) linked to the castor oil and blocks of poly(ethylene oxide) linked to the poly(propylene oxide). GPC analysis shows the molecular weights as shown in Table 2. Samples are tested according to the Bottle Demulsification test (20 minute water drop), and the Relative Solubility Number Test and results are shown in Table 2. As a comparison, samples of commercial demulsifier are tested according to the Bottle Demulsification test (20 minute water drop) and shown as CE1 to CE5. Table 2 Demulsifier PO / EO / (PO+EO) / EO / PO Mn, Mw, PDI RSN Dose Bottle Trademark Castor Castor Castor oil Mole Da Da (Mw / Mn) (ppm) Test - 20 Sample ID oil oil mole Ratio Min )

Claims

CLAIMS: We claim:

1. A surfactant that is a reaction product made by: (a) Providing a tri-ester compound that comprises three fatty acids having pendant hydroxyl groups linked to a triol by ester linkages between the acid groups of the fatty acids and the hydroxyl groups of the triol; (b) Alkoxylating the tri-ester compound in step (a) by reacting the tri-ester compound with alkylene oxide monomers suitable to form blocks of lipophilic poly(alkylene oxide) polymer, in the presence of a base; and (c) Further alkoxylating the product of step (b) by reacting the product of step (b) with alkylene oxide monomers suitable to form blocks of hydrophilic poly(alkylene oxide) polymer, in the presence of a base.

2. The surfactant of Claim 1 wherein the surfactant has a Relative Solubility Number from 8 to 20.

3. The surfactant of Claim 2 wherein the monomers in step (b) contain primarily propylene oxide and / or butylene oxide and the monomers in step (c) contain at least 80 mole percent ethylene oxide.

4. The surfactant of Claim 2 wherein the monomers in step (b) contain from 90 to 100 mole percent propylene oxide and butylene oxide; and the monomers in step (c) contain from 90 to 100 mole percent ethylene oxide.

5. The surfactant of Claim 2 wherein the molar ratio of alkylene oxide monomers used in steps (b) and (c) to the tri-ester compound is from 50 to 300.

6. The surfactant of Claim 2 wherein the aggregate molar ratio of ethylene oxide monomer to other alkylene oxide monomers in steps (b) and (c) is from 0.5 to 20.

7. The surfactant of Claim 2 wherein the aggregate molar ratio of ethylene oxide to other alkylene oxide monomers in steps (b) and (c) is from 1 to 12.

8. The surfactant of Claim 2 wherein the surfactant has a number average molecular weight from 2000 g / mol to 5000 g / mol.

9. The surfactant of Claim 2 wherein the tri ester compound in step (a) is derived from castor oil.

10. The surfactant of Claim 2 wherein: (a) the tri ester moiety in the tri-ester compound in step (a) is derived from castor oil; and (b) the surfactant has a number average molecular weight from 2000 g / mol to 5000 g / mol; and (c) wherein the aggregate molar ratio of ethylene oxide monomers to other alkylene oxide monomers in steps (b) and (c) is from 1 to 12.

11. The surfactant of any of Claims 1 through 10 wherein the surfactant comprises compounds represented by Formula 5:w (a) Each Z is independently selected from hydrogen or a moiety illustrated in Formulae 5a to 5e;(b) Each R1is independently a fatty organic moiety; (c) Each (R2-O)aindependently represents a lipophilic poly(alkylene oxide block), in which each (R2-O) independently represents alkylene oxide repeating unit in the lipophilic poly(alkylene oxide) block, and each “a” independently represents the number of repeating units in the lipophilic poly(alkylene oxide) block; (d) (R3-O)b independently represents a hydrophilic poly(alkylene oxide block), in which each (R3-O) independently represents alkylene oxide repeating units in the hydrophilic poly(alkylene oxide) block, and each “b” represents the number of repeating units in the hydrophilic poly(alkylene oxide) block; and(e) each R4independently represents a hydrogen or an alkyl moiety.

12. The surfactant of Claim 11 wherein the surfactant comprises compounds represented by Formula 4. 13.at least 50 weight percent compounds represented by Formula 4.

14. A process to prevent or break a water-in-oil emulsion caused by the mixing of water and oil, comprising the step of contacting the water, oil or emulsion with a demulsifier that comprises at least 10 weight percent of a surfactant of Claim 11.

15. The process of Claim 14 wherein the oil is crude oil and the ratio of oil to surfactant in the demulsifier is from 1 ppmw to 100,000 ppmw.

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