WO2015017140A1

WO2015017140A1 - Foam-free synthesis of co-polyhydroxyaminoether

Info

Publication number: WO2015017140A1
Application number: PCT/US2014/047113
Authority: WO
Inventors: Cesar E. MEZA; Stephen M. Hoyles; Shawn J. Maynard; Juan G. SOLIS; Flor A. Castillo
Original assignee: Dow Global Technologies Llc
Priority date: 2013-07-31
Filing date: 2014-07-18
Publication date: 2015-02-05

Abstract

A process includes an initial synthesis including mixing an epoxy and an aqueous amine solution to form a reaction mixture and addition of water to the reaction mixture while mixing. The amine includes: where R⁵ is hydrocarbyl, R⁶ is hydrogen, methyl, hydrocarbyl or mixtures thereof, and q is one to 1000; at least 90 mole-percent of the epoxy molecules have a reactive functionality in a range of one to two and an average reactive functionality of two or less; at least 90 mole- percent of the amine molecules have a number of reactive protons in a range of one to two and an average number of reactive protons of two or less; the amine is present at an excess mole ratio of reactive sites relative to epoxy reactive sites; and the temperature of the reaction mixture during the water addition is maintained between zero and 68 degrees Celsius.

Description

FOAM-FREE SYNTHESIS OF CO-POL YHYDROXYAMINOETHER

BACKGROUND OF THE INVENTION

Field of the Invention

The present invention relates to a method of manufacturing co- polyhydroxyaminoether.

Introduction

Recovery of subterranean oil can be hindered by the presence of water. The presence of water has been particularly troublesome with respect to hydraulic-fracture stimulation of oil reservoirs with water layers directly above and/or below the oil reservoir, as is the case in many reservoirs in Western Siberia. Hydraulic-fracture stimulation of oil reservoirs typically involves pumping one or more fluid down a well to fracture

subterranean formations and increase the permeability of oil through subterranean formations to enhance oil recovery at the well. Unfortunately, the fracturing can also increase permeability of water through the subterranean formations. Stimulation of oil recovery in some locations can result in water cuts from 90-100% (see, Ldut'ko, Alex et al., Society of Petroleum Engineers 158389, 2012). As the water cut in a well recovery increases, the economics of the oil recovery decreases and the ecological challenge of dealing with waste water increases. Therefore, it is desirable to minimize the concentration of water in oil recovered during hydraulic-fracture stimulated oil recovery.

Co-polyhydroxyaminoether (cPHAE) is one class of molecule that has proven useful as an additive in hydraulic-fracture stimulation to increase the oil concentration (or cut) from an oil well. cPHAE has been shown to reduce the amount of water recovered from subterranean hydrocarbon-bearing formation thereby increasing the production rate of hydrocarbons from the formation. See, for example, US7417011 B2, US7893136 B2 and US7678872 B2. Therefore, cPHAE can minimize water cuts during oil recover in stimulated oil recovery activity, making it a valuable additive for use in recovering oil from oil reservoirs with water layer directly above and/or below the oil reservoir. As oil becomes more valuable it becomes more important to be able to recover oil from water-rich subterranean locations. Therefore, cPHAE is an important material to the oil industry. Improving synthesis methods for cPHAE would be desirable in order to facilitate the economic availability of the cPHAE. In particular, since the oil industry uses cPHAE in the form of an aqueous dispersion, improving a synthesis method for preparing cPHAE as an aqueous dispersion is particularly desirable.

BRIEF SUMMARY OF THE INVENTION

The present invention offers an improvement to the method of synthesizing a cPHAE aqueous dispersion. It has been discovered that foaming is a common problem in the synthesis of a cPHAE aqueous dispersion. Foaming during synthesis is problematic in a number of ways. For instance, unstable foaming can result in inefficient mixing of reactants, which results in long reaction times and inhomogeneous reaction products.

Worse yet, stable foaming further can occur resulting in a foam material that does not readily flow from a reactor and requires shutting down the process line while the foam is removed from the reactor. Upon discovering the tendency for foaming to occur during the synthesis of cPHAE, the inventors discovered how to avoid foaming and thereby efficiently prepare a more homogeneous product than obtained if foaming occurs and without having to shut down the reactor to remove foam.

Surprisingly, the present invention is a result of discovering that foaming can be avoided by controlling the temperature during the water addition step in forming a cPHAE dispersion. In particular, foaming surprisingly can be avoided by keeping the temperature below 68°C during the water addition step of a synthesis comprising an initial synthesis of cPHAE and a water addition step. It is further desirable to keep the reactor temperature below 70 degrees Celsius (°C) and typically in a range of 55-70°C during the initial synthesis step to avoid foaming. In a first aspect, the present invention is a process comprising the following steps:

(a) an initial synthesis comprising mixing an epoxy into an aqueous amine solution to form a reaction mixture; and (b) addition of water to the reaction mixture while mixing; wherein the amine comprises an amine having the following structure: H₂N-CHCH₂ ( OCHCH₂ ^— OR⁵ where R⁵ is hydrocarbyl, R⁶ is hydrogen, methyl, hydrocarbyl or mixtures thereof, and q is one to 1000; and where:

(i) at least 90 mole-percent of the epoxy molecules have a reactive functionality that is in a range of one to two and at the same time the average reactive functionality of the epoxy is two or less;

(ϋ) at least 90 mole-percent of the amine molecules have a number of reactive protons in a range of one to two and at the same time the average number of reactive protons of the amine is two or less;

(iii) the amine is present at an excess mole ratio of reactive sites relative to epoxy reactive sites; and

(iv) the temperature of the reaction mixture during the water addition is

maintained above zero degrees Celsius and below 68 degrees Celsius.

The process of the present invention is useful for making an aqueous dispersion of cPHAE, which is useful as an additive in subterranean oil recovery.

DETAILED DESCRIPTION OF THE INVENTION

Test methods refer to the most recent test method as of the priority date of this document unless a date is indicated with the test method number. References to test methods contain both a reference to the testing society and the test method number. Test method organizations are referenced by one of the following abbreviations: ASTM refers to ASTM International (formerly known as American Society for Testing and Materials); EN refers to European Norm; DIN refers to Deutsches Institute fiir Normung; and ISO refers to International Organization for Standards.

And/or" means "and, or as an alternative". "Stirring" includes any form of mixing including mixing with a rotating element such as a blade, shaking, and/or swirling. All ranges include endpoints unless otherwise indicated.

The present invention is a process that includes an initial synthesis comprising mixing an epoxy into an aqueous amine solution to form a reaction mixture. The aqueous amine solution and epoxy can be mixed together by any means including cofeeding into a reactor, feeding an epoxy into a reactor containing an aqueous amine solution or feeding an aqueous amine solution into a reactor containing an epoxy. Desirably, the epoxy and aqueous amine solution are stirred in order to facilitate thorough mixing and efficient reaction between the epoxy and amine. Most desirably, feed an epoxy into an aqueous amine solution while mixing in order to keep the viscosity of the components as low as possible while conducting the initial synthesis, which makes thorough mixing easier.

The epoxy can be a single type of epoxy or a combination of more than one type of epoxy. At least 90 mole-percent (mol ), preferably 95 mol or more, still more preferably 99 mol or more, and conceivably 100 mol of the epoxy molecules have a reactive functionality (that is, number of oxiranes per molecule) that is in a range of one to two. At the same time, the average reactive functionality of the epoxy, or combination of more than one epoxy, is two or less.

Desirably, the epoxy comprises or consists of a diglycidyl ether of a bisphenol-A. A desirable epoxy is 2,2'-[methylethylidenebis(4,l-phenyleneoxymethylene)]bisoxirane ( also known as DER 332).

The amine can be a single type of amine or a combination of more than one type of amine. Desirably, the amine comprises or is an amine having one or two reactive amino protons per molecule. A reactive amino proton is a proton that reacts with epoxy under the initial synthesis conditions described in the present invention. It is particularly desirable for the amine to comprise a primary monoamine functionalized poly(alkylene oxide) such as the ethylene oxide/propylene oxide monoamine sold under the tradename JEFF AMINE™ M- 2070 (JEFF AMINE is a trademark of JP Morgan Chase Bank, N.A).

The amine (which can be a mixture of amines) provides hydrophilic character to the resulting molecule sufficient to enable the resulting molecule to disperse in water.

Therefore, it is desirably for at least 90 mol , preferably 95 mol or more, still more preferably 99 mol or more, and conceivably 100 mol of the amine molecules to have a reactive functionality (that is, number of reactive proton per molecule) that is in a range of one to two. At the same time, the average number of reactive protons of the amine, or mixture of amines, is two or less. If the average number of protons of the amine, or mixture of amines, exceeds two then the reaction tends to gel and inhibit processing. The process can tolerate a small amount of amine having more than two reactive amino protons, but desirably is free from amines having more than two reactive amino protons to avoid gelling.

The amine can comprise an amine having the following structure (Structure I):

H₂N-CHCH₂ ( OCHCH₂ ^— OR^"

R^c where R⁵ is hydrocarbyl, R⁶ is selected from hydrogen, methyl, hydrocarbyl or mixtures thereof, and q is a number in a range of one to 1000. It is particularly desirable for the amine to comprising an amine having the structure I and the epoxy to comprise diglycidyl ether of bisphenol A. When diglycidyl ether of bisphenol A is used to make cPHAE then the resulting polymer has demonstrated a desirable level of hydrophilicity for dispersing in water as well as ability to adhere to rock formations in underground oil reservoirs.

The amine can comprise a chain terminator selected from a group consisting of monofunctional secondary amines, monofunctional carboxylic acids, monofunctional phenolics, monofunctional alcohols and water. Diethanol amine is especially desirable as a chain terminator because it provides terminal hydroxyl groups which increase the hydrophilicity of the resulting molecule.

Desirably, the amine comprises monoethanolamine and diethanolamine.

The process of the present invention desirably includes an amine comprising a monofunctional primary polyether amine with an average molecular weight of about 2,000 and the epoxy comprising 2-[[4-[4-[4-(oxiran-2-ylmethoxy)phenyl]propan-2- yl]phenoxy] methyl] oxirane. Preferably, the amine further comprises monoethanolamine and diethanolamine.

It is desirable to select the amine and epoxy, and relative concentrations of amine and epoxy, so that the process of the present invention produces a cPHAE product having the following composition:

where A is:

and B is:

and X is a value in a range of 30-50 (preferably, approximately 40), Y is a value in a range of 4-7 (preferably, approximately 6), Z is a value in a range of 60-80 (preferably, approximately 70), a is a value in a range of 8-12 (preferably, approximately 10) and b is a value in a range of 28-34 (preferably, approximately 31).

The amine is desirably present at an excess mole ratio of reactive sites relative to the epoxy. That is, it is desirable to have the concentration of epoxy and amine such that the epoxy will be consumed in a reaction between the two components before the amine will be consumed. Desirably, the moles of epoxy reactive sites are 0.1 or more, preferably 0.5 or more and can be up to 0.99 or less for each mole of amine reactive sites (reactive amino protons).

The aqueous amine solution desirably comprises water at a volume of at least 50 volume-percent (vol%) based on total combined volume of epoxy and aqueous amine solution.

The initial synthesis step begins with combination of epoxy and amine components and is complete after all of the epoxy and amine are combined in the reaction mixture and the concentration of epoxy becomes undetectable in the reaction mixture by carbon 13 analysis (chloroform-d/chromium acetylacetonate using 400 megahertz spectrometer using 4000 scans per data file, 6 second pulse repetition delay, spectral width of 25,200 Hertz and file size of 32,000 data points resulting in detection limit of 0.3 mole-percent epoxy). The initial synthesis step can consist of only a period during which epoxy and amine are being added to one another provided the addition is slow enough to allow all of the epoxy to react during this period. Typically, the initial synthesis step comprises a first digestion period following addition of all of the epoxy and amine to the reaction mixture. The first digestion step is a period of time where the reaction mixture is mixed after all of the epoxy and amine are added to the reaction mixture. The first digestion step provides time and opportunity for the epoxy to react with the amine.

It is preferable to maintain the temperature of the reaction during the initial synthesis at a temperature of 70 degrees Celsius (°C) or lower, preferably 67°C or lower, more preferably 66°C or lower, yet more preferably 65°C or lower and still more preferably 60°C. At the same time, it is typical to run the initial synthesis while maintaining a temperature of the reaction at a temperature of greater than zero °C, preferably 20°C or higher, more preferably 25°C or higher, yet more preferably 50°C or higher and still more preferably 55°C or higher. Cool temperatures lower the chance of foam formation while higher temperatures facilitate low viscosity, rapid epoxy conversion and easy mixing of the reaction mixture.

The process further requires addition of water to the reaction mixture while continuing mix the reaction mixture (for example, while continuing to stir the reaction mixture) to form a dispersion of the cPHAE reaction product of the initial reaction in water. The water addition step requires adding water beyond that water present as part of the aqueous amine solution. Water addition can begin prior to completion of the initial synthesis step or can begin after completion of the initial synthesis step. Desirably, water addition occurs even after completion of the initial reaction whether water addition began prior to or after completion of the initial reaction. The water serves as a continuous phase in which the reaction mixture products (cPHAE) becomes dispersed.

It is with respect to the water addition step that the present invention provides a particular surprising result. During exploration of the synthesis process of aqueous cPHAE dispersion the present inventors discovered undesirable foaming of the reaction mixture tends to occur unless the temperature of the reaction mixture is maintained at a temperature below 68°C, preferably at a temperature of 67°C or lower, more preferably 65°C or lower and yet more preferably 63°C or lower and even more preferably 60°C or lower during the water addition step. Foaming during the process is undesirable for the reasons already stated above including the fact that foaming inhibits reactant mixing, uniformly dispersing product and can prevent flow of reaction mixture from a reactor in which the initial synthesis, first digestion step and/or water addition step occur. Hence, the present invention offers a process for producing cPHAE that avoids foam formation by maintaining the temperature of the reaction mixture during the water addition step at a temperature below 68°C, preferably at a temperature of 67°C or lower, more preferably 65°C or lower, still more preferably 65 °C or lower, yet more preferably 63 °C or lower and even more preferably 60°C or lower. Typically, water addition occurs at a temperature higher than zero °C so as to prevent the water from freezing. Preferably, water addition occurs at a temperature of 20°C or higher, more preferably 25°C or higher, yet more preferably 45°C or higher, even more preferably 50° or higher, still more preferably 55°C or higher. The total amount of water present in the final dispersion after the process is complete is typically 60 wt or more, preferably 70 wt or more, still more preferably 80 wt or more, yet more preferably 90 wt or more and can be 95 wt or more and even 99 wt or more of the total dispersion weight. Desirably, at least 60 wt , more preferably 70 wt or more, yet more preferably 80 wt or more of the total water in the resulting dispersion is added after addition of the epoxy and amine is complete, more preferably after the initial synthesis is complete. It is desirable to have 20 wt or more, preferably 30 wt or more and at the same time it is desirable to have 40 wt or less of the total water present in the resulting dispersion to be present before the initial synthesis is complete, preferably before addition of the epoxy (that is, combined with the amine into which the epoxy is added).

Mixing is important during the water addition step to disperse the cPHAE into the water. Depending on how quickly the water addition occurs and how homogeneous of a dispersion is desired the process can further comprise a dispersion digestion step after all of the water has been added in the water addition step. During the dispersion digestion step the water and reaction mixture are mixed to increase homogeneity of the cPHAE dispersion.

After completion of the water addition and, if included, the dispersion digestion step the resulting aqueous cPHAE dispersion is complete. Optionally, the dispersion can be cooled before removing from the reaction vessel. Notably, the entire process preferably occurs in a single reaction vessel.

Examples

Prepare the following examples using a lab scale reactor comprising: (a) a 2-liter flanged reactor fitted with a clamped-on reactor head; (b) an electrical heating mantle to control the reactor temperature using a digital temperature controller with surface mounted thermocouples; (c) an stirring agitator with two sets of impellers (A310 and PBT) each with 3-picthed blades and a blade length of about 2.54 centimeters (cm), the impellers set 8.9 cm (3.5 inches) apart with the bottom impeller 3.8 cm from the bottom of the reactor vessel; (d) an electric stir motor (Caframo RXR); (e) four polytetrafluoroethylene baffles separated 90 degrees; (f) a liquid epoxy resin (LER) charge vessel with a heat traced/insulated 500 milliliter glass vessel fitted with a bottom drain and set up for metered flow using an FMI positive displacement pump through 0.3175 cm (1/8 inch) stainless steel tubing; (g) an aqueous feed using an ISCO 500D syringe pump; (h) tubing, Omega heat tracing and a pair of thermocouples around the aqueous and LER feed lines; (i) a nitrogen sweep on the reactor vessel including a regulator and needle valve; and (j) a cold finger (approximately one liter in capacity) fitted onto the head to provide some condensation/reflux capability and minimize volatile losses in the nitrogen sweep.

Charge the reactor vessel with and aqueous amine mixture consisting of 21.7 grams

(g) monoethanolamine, 6.0 g diethanolamine, 105.7 g polyetheramine (Jeffamine™ M5020 polyetheramine, Jeffamine is a trademark of JPMorgan Chase Bank, N.A.) and 127.7 g water. This amine mixture is about 20 volume-percent of the reactor vessel volume.

Commence an initial synthesis by feeding to the aqueous amine mixture in the reactor vessel 147.7 g epoxy (2,2'-[methylethylidenebis(4,l- phenyleneoxymethylene)]bisoxirane; DER 332 epoxy resin from The Dow Chemical Company). Feed the epoxy over a period of time (see Table 1) using an FMI positive displacement pump while mixing at a rate of 400 to 685 revolutions per minute (impeller tip speed range is 1.2 to 2.2 meters per second), preferably 515 revolutions per minute.

Maintain the temperature of the contents of the reactor vessel at an initial reaction temperature as listed in Table 1 below.

After all of the epoxy resin has been added to the reactor vessel, commence the first digestion ("FD") step by continuing mixing of the contents of the reaction vessel at the same rate as during the initial synthesis for a FD time (see Table 1) while maintaining the reactor at a FD temperature.

After the FD step, feed in 991.2 g of water using and ISCO 500D syringe pump over a water addition time as shown in Table 1. Maintain the reactor vessel at a water addition temperature as shown in Table 1.

After water addition is complete conduct a dispersion digestion ("DD") step for 1.5 hours by mixing the reactor vessel contents at the same rate as during the initial reaction step while maintaining the reactor vessel at a DD temperature.

Upon completion of the DD step allow the reactor contents to cool overnight (approximately 10 hours) a temperature below 60°C, preferably in a range of 20-25°C, and remove the contents from the reactor vessel. Identify whether the reactor vessel contents are foamed or not. Those results are recorded in Table 1 for each of the examples. Table 1

An analysis plot of the data for Exs 1-8 and Comp Exs A-D reveals that all syntheses with the Initial Reaction Temp below 70°C and Water Addition Temp below 68°C results in no foam formation while when those temperatures exceed 68°C foam formation occurred.

Example 9 reveals that even when the Initial Reaction Temperature exceeds 70°C, no foam formation occurs when the Water Addition Temp is below 68°C. Example 10 reveals that even when the Initial Reaction Temperature is below 70°C and the water addition temperature is 68°C foaming occurs. Therefore, the data reveals that the critical parameter is temperature during water addition with respect to determining if foaming occurs and further reveals that when the Water Addition Temp is below 68°C the reaction does not produce foam.

Claims

CLAIMS:

1. A process comprising the following steps:

a. an initial synthesis comprising mixing an epoxy into an aqueous amine solution to form a reaction mixture; and

b. addition of water to the reaction mixture while mixing; wherein the amine comprises an amine having the following structure:

H₂N-CHCH₂ ( OCHCH₂ ^— OR⁵

R⁶ R⁶

where R⁵ is hydrocarbyl, R⁶ is hydrogen, methyl, hydrocarbyl or mixtures thereof, and q is one to 1000; and where:

(ii) at least 90 mole-percent of the amine molecules have a number of reactive protons in a range of one to two and at the same time the average number of reactive protons of the amine is two or less;

(iv) the temperature of the reaction mixture during the water addition is

maintained above zero degrees Celsius and below 68 degrees Celsius.

2. The process of Claim 1, wherein the aqueous amine solution contains water at a volume of at least 50 volume-percent of the total combined volume of aqueous amine solution and epoxy.

3. The process of any previous Claim, wherein both the initial synthesis and water addition occur in a single reaction vessel.

4. The process of any previous Claim, further characterized by the temperature during the initial synthesis being maintained above zero degrees Celsius and at or below 70 degrees Celsius.

5. The process of any previous Claim, further characterized by the epoxy being a

diglycidyl ether of a bisphenol-A.

6. The process of any previous Claim, further characterized by the amine comprising a primary monoamine functionalized poly(alkylene oxide).

7. The process of any previous Claim, further characterized by the amine in step (a) comprising a chain terminator selected from a group consisting of: monofunctional secondary amines, monofunctional carboxylic acids, monofunctional phenolics, monofunctional alcohols and water.

8. The process of any previous Claim, further characterized by the amine comprising a monofunctional primary polyether amine with an average molecular weight of about 2,000 and the epoxy comprising 2-[[4-[4-[4-(oxiran-2-ylmethoxy)phenyl]propan-2- yl] phenoxy] methyl] oxirane .

9. The process of Claim 8, further characterized by the amine further comprising

monoethanolamine and diethanolamine.

10. The process of any previous Claim, further characterized by the epoxy and amine components being selected both in composition and concentration so as to produce a product having the following composition:

where A is:

and B is:

11. and X is a value in a range of 30-50, Y is a value in a range of 4-7, Z is a value in a range of 60-80, "a" is a value in a range of 8-12 and "b" is a value in a range of 28-34.

12. The process of any previous claim further comprising a dispersion digestion step after the water addition step is complete during which the reaction mixture and water are mixed sufficiently to form a dispersion in a water-continuous phase.

13. The process of any previous Claim, further characterized by the initial synthesis step comprising addition of epoxy to amine followed by a first digestion period after all of the epoxy has been added and during which the reaction mixture is mixed prior to the water addition step.