ALCOHOL ALKOXYLATE MIXTURES AS CONCENTRATED AQUEOUS DEFOAMING AGENTS

Abstract

The use of an alcohol alkoxylate or a mixture of alcohol alkoxylates as a concentrated defoamer, antifoam and / or deaerator wherein the alcohol alkoxylate or mixture of alcohol alkoxylates comprises at least one alcohol alkoxylate, wherein the alcohol alkoxylate has a molecular structure as shown in [I]: RO-(CH2(CH3)CHO)m-(CH2CH2O)nH wherein R is a branched and / or linear alkyl group having 20 to 50 carbon atoms, m = 10-40 and n = 0-5.

Description

ALCOHOL ALKOXYLATE MIXTURES AS CONCENTRATED AQUEOUS DEFOAMING AGENTS The present invention relates to alcohol alkoxylates or mixtures thereof and the use of such alcohol alkoxylates or mixtures as concentrated aqueous defoamers, antifoaming agents, and deaerators. More specifically, the alcohol alkoxylates relate to linear long-chain alcohol alkoxylates, which are used as additives for foam prevention, foam destruction, and deaeration in various application areas. BACKGROUND OF THE INVENTION AND DISCUSSION OF THE PRIOR ART In various industrial processes, the occurrence of foam creates problematic environments that, for example, could negatively impact reaction rates and prevent optimal, normal operation. Current methods for foam control include mechanical means such as the use of diverters and mixing control systems. In conjunction, chemical defoamers or antifoams are frequently used. There are different classes of additives used in the prevention, removal, and mitigation of foam formation that work through different mechanisms and are effective against different types of foam (e.g., macro versus micro foams). While these classes differ in principle, the terms used to define them are often used interchangeably. Furthermore, many > Π NCNN CÜ N And if not, most additives do not only perform one function. Antifoams are additives that prevent or inhibit foam formation from the outset and are typically added to a potentially foaming solution before foaming begins. Defoamers are compounds added to mixtures to break down existing foam, targeting the surface foam (macrofoam) and promoting rapid foam collapse. Deaerators function similarly to defoamers, also breaking down existing foam, but they target the subsurface foam (microfoam). Well-known defoamers, antifoams, and deaerators include, among others, silicone oils and lower alkylene glycol block copolymers. US Patent 6,534,550 describes defoaming compositions comprising alcohols, alcohol alkoxylates, emulsifying components, and water for preventing and inhibiting foam formation in aqueous systems. The compositions in US Patent 6,534,550 are emulsions that require precise mixing of several different components to achieve the desired results. US Patent 6,562,875 describes the use of alkoxylated alcohols in conjunction with emulsifiers such as anionic surfactants as antifoams in the paper industry. All prior art references are incorporated herein by reference for all purposes. However, there is an ongoing need for low-cost, simple, stable, concentrated aqueous defoamers, antifoams, and / or deaerators for effective application in the chemical, household, and industrial process industries. OBJECTIVE OF THE PRESENT INVENTION The advantage of the inventive compounds or mixtures of compounds and their use in aqueous systems is the provision of concentrated surfactants with ultra-low particle sizes. The nature of the specific alcohol alkoxylates described results in insoluble, yet ultra-dispersible surfactants for the effective defoaming, antifoaming, and deaeration of aqueous feeds present in various chemical, domestic, and industrial processes. BRIEF DESCRIPTION OF THE INVENTION The present invention relates to a range of alcohol alkoxylates and their use as defoamers, antifoams, and / or deaerators for aqueous phases in various application areas. These include general defoaming, antifoaming, and deaerating applications, specifically useful in, but not limited to, oil and gas applications, the agrochemical field, water treatment processes, as well as areas of technology such as > Π NCNN CÜ N Pulp and paper, fermentation, detergents, metalworking fluids, paints and coatings, emulsion polymerization and construction. The invention specifically teaches the use of an alcohol alkoxylate or an alcohol alkoxylate mixture as a concentrated defoamer, antifoam and / or deaerator wherein the alcohol alkoxylate or alcohol alkoxylate mixture comprises at least one alcohol alkoxylate, wherein the alcohol alkoxylate has a molecular structure as shown in [I]: RO-(CH2(CH3)CHO)m-(CH2CH2O)nH [I] wherein R is a branched and / or linear alkyl group having 20 to 50 carbon atoms, preferably 20 to 30 carbon atoms, m = 10-40, preferably 20-25, n = 0-5, preferably 1-2. The mole ratio of PO to mole ratio of EO is preferably 14:1 to 35:1, more preferably 14:1 to 20:1, and much more preferably 20:1. One feature of the invention, among others, is the extremely low dosage required. The alcohol alkoxylate or alcohol alkoxylate mixture is added at a concentration of between 50 ppm and 3,000 ppm, more preferably between 100 and 2,500 ppm, and much more preferably between 100 and 500 ppm. > Π NCNN CÜ N OR The compounds described in this invention exhibit > Π NCNN CÜ N It has good chemical and thermal stability. The operating temperature can vary between 20 and 100°C, but is preferably between 20 and 80°C. Furthermore, the alcohol alkoxylates described provide excellent defoaming, antifoaming, and deaerating performance in concentrated form and are highly active. The use of alcohol alkoxylate or alcohol alkoxylate mixtures is most beneficial when no additional liquid or solid additives, such as emulsifiers, solvents, or carriers, are added. Additional advantages include, but are not limited to, the compounds of the invention being silicone-free, non-explosive, non-flammable, highly salt-tolerant, and non-corrosive. The invention further describes a method for defoaming and / or deaerating and / or defoaming an aqueous foam, wherein the aqueous foam comprises an aqueous phase and a gas, and wherein the method comprises: i) providing a composition comprising at least: an alcohol alkoxylate, wherein the alcohol alkoxylate has a molecular structure as shown in [I]: RO- (CH2(CH3) CHO)m- (CH2CH2O)nH [I] where R is a branched and / or linear alkyl group having 20 to 50 carbon atoms, preferably 20 to 30 atoms, m = 10-40, preferably 20 to 25, n = 0-5, preferably 1 to 2. > Π NCNN CÜ N U ii) bringing the aqueous foam into contact with the composition whereby the aqueous foam collapses. The alcohol alkoxylate or alcohol alkoxylate mixture of the present invention preferably has an average particle size less than 4 bpm, more preferably less than 15 bpm, and much more preferably less than 4 bpm. The low particle size improves the dispersibility of the defoamer / antifoam in aqueous feeds, resulting in readily dispersible compounds with minimal mixing or agitation required. Unlike prior art, the present invention is a concentrated defoamer that does not require emulsifiers or similar agents to achieve foam reduction / prevention. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 shows a comparison of the reduction in foam height after additive dosages. Fig. 2 shows a comparison of final foam heights after additive dosages. Fig. 3 shows the defoaming performance of various defoamers. Fig. 4 shows the foam reduction achieved by various defoamers at a dosage of 500 ppm. Fig. 5 shows the defoaming performance of C2030-2ORO-1EO at various dosages. Fig. 6 shows the defoaming performance of > Π NCNN CÜ N OR 02030-2 ΟΡΟ-1ΕΟ at various temperatures. Fig. 7 shows the performance of defoaming agents compared to commercial samples. Fig. 8 shows the half-life for various defoamers. Fig. 9 shows the performance of defoamers with various numbers of PO and EO units. DETAILED DESCRIPTION OF PREFERRED MODALITIES The surfactants of the present invention are effective defoamers, antifoamers, and / or deaerators for a wide variety of aqueous phases. The performance of the compositions can be optimally designed by adjusting the hydrophobic structures of the compounds, along with the number of propylene oxide (PO) and / or ethylene oxide (EO) units, for a specific application. Materials A number of surfactants, specifically alkoxylated alcohols, were synthesized according to standard procedures (see Experimental section) and their properties were characterized. The materials used in various tests to determine the efficiency of compounds such as defoamers / antifoamers / deaerators are shown in Table 1: Table 1: Materials used to evaluate defoaming / antifoaming / deaerating properties > Π Ν C Ν Ν C ϋ Ν ΐ ο Trade name of alcohol Carbon chain length of alcohol Alcohol structure Number of propylene oxide (PO) units Number of ethylene oxide (EO) units ALFOL20+ C20-30 linear 35 5 ALFOL20+ C20-30 linear 35 1 ALFOL20+ C20-30 linear 35 0 ALFQL20+ C20-30 linear 20 1 ALFOL20+ C20-30 linear 19 2.5 ALFOL20+ C20-30 linear 19 0 ALFOL20+ C20-30 linear 14 5 ALFOL20+ C20-30 linear 14 1 ALFOL20+ C20-30 linear 14 0 UNILIN alcohol C20 + linear 30 0 Behenyl alcohol C20-22 linear 20 1 ISOFOL12 C12 (Guerbet) 100% 2- alkyl branched (1.0 branching / molecule) 32 3 ISOFOL2 0 C20 (Guerbet) 100% 2- alkyl 20 1 Branched (1.0 branch / molecule) ISOFOL23 C24-26 50% Branched (2.16 branch / molecule) 25 1 ISOFOL32 C32(Guerbet) 10 0 % 2 - alkyl branched (1.0 branch / molecule) 15 1 All examples represented by trade names are marketed by Sasol Performance Chemicals, except for UNILIN, which was acquired from Baker Hughes. Table 2 shows the commercial defoamers from technique 5 that were used for comparative experiments. Table 2: Defoamers used for comparative examples Name Description Structure of Alcohol BASLPUR DF 5* C1618-28PO-2SO Linear EMULDAC 251 PE * * C1618-25PO-1EO Linear PDMS (OH terminated) Polydimethylsiloxane (MW = 550 - 3,200 Da) N / A Polypropylene glycol (PP_Mol wt = 400 Da N / A Polypropylene glycol (PPG-900) Mol wt = 900 Da N / A Sold by BASF Sold by Sasol Performance Chemicals Sold by Carpenter Table 3 lists the foaming agents that were used 5 for various defoaming experiments. Table 3: Commercial foaming agents used for defoaming experiments NAME DESCRIPTION HE 100C* C610-3.5EO Coco Sulfate DEA Coco diethanolamide CAPE Cocamidopropyl Betaine C12-18 APG C12-16 Alkyl Polyglycoside C12 LAS C12 Linear Alkylate Sulfate > Π NCNN CÜ N OR *Available from Thatcher Chemicals EXPERIMENTAL SECTION Synthesis of alkoxylated alcohols (PO / EO) used for experiments Alcohols ranging from C12 to C32 were propoxylated and ethoxylated using well-known alkoxylation catalysts such as double metal cyanide (DMC) or KOH. Each alcohol product was targeted to consist of 10 to 40 moles of propylene oxide and 0 to 5 moles of ethylene oxide. Samples were prepared in a 600 mL Parr reactor using the alkoxylation catalyst of choice. Each alcohol was propoxylated using purified propylene oxide at 130–150 °C and 40–60 psig and then ethoxylated using purified ethylene oxide at 150–160 °C and 40–60 psig in a single, continuous run. Experiment 1: The first test parameters aimed to compare the ability of the additives to destroy stable surface foam and act as a true defoamer. Experimental Procedure: The foam reduction test aimed to compare each defoamer's ability to inactivate or destroy existing foam. The test was performed by pouring 40 ml of nanopure water containing 2500 ppm of a commercial defoamer (C610-3.5 Sulfate) into the glass column > Ϡ NCNN CÜ N The foam analyzer was used to measure foam height. The solution was agitated for 30 seconds at 8000 rpm to generate foam. Agitation was stopped, and the foam was allowed to stabilize for 1 minute. After 1 minute, the initial foam height was recorded, and defoamer was added to the foamed solution at 2500 ppm. The solution was agitated for 1 minute at 8000 rpm and then stopped. The foam was allowed to stabilize for 30 seconds, and the final foam height was recorded. The test was repeated for each defoamer. A target test was also performed using the same procedure, except that no defoamer was added. The total percentage foam reduction from initial to final foam height was calculated for each defoamer (see Figure 1). The final foam heights (see Figure 2) were also compared for all defoamers to the target or reference point. Figures 1 and 2 show the decreases in defoamer performance as follows: C2030-20PO1EO > C161825PO-1EO > C1618-28PO-2EO-PDMS, OH finished > PPG 400. Experiment 2: Experimental Procedure: A 40 ml solution containing 2500 ppm of HF100C (610-3.5EO sulfate - AES) in H2O DI was added to the Kruss foam analyzer and sprayed with air at a rate of 0.2 L / min through a bottom-registered or sintered disc with an average pore size of 100-160 µm. Once the height of > Ϡ Ν C Ν Ν C ϋ 13 ί The foam reached approximately 150 mm. While air spraying continued, 2500 ppm of defoamer was added to the solution. Spraying continued until a total spray time of 500 seconds had elapsed, or the foam height reached the maximum capacity of the Kruss instrument. This test allowed for the evaluation of the amount of initial foam inactivation immediately after the addition of the defoamer (defoaming) along with the defoamer's ability to maintain this initial inactivation over time (antifoaming). Figure 3 clearly illustrates the superior defoaming as well as the antifoaming performance of an example of an inventive compound (C2030-20PO-1EO) over an extended period of time, when compared to commercial samples. Experiment 3: The same experimental procedure as described for Experiment 1 was used. Figure 4 compares the reduction in foam height after a dosage of 500 ppm of various additives, respectively. Figure 4 shows the decreases in defoamer performance as follows: C2030-2 ΟΡΟ-1EO > (50 / 50% mixture by weight C2030-20POlEO / GuerbetC2426-25PO-1EO) > C2022-20PO-1EO > GuerbetC242625PO-1EO > GuerbetC32-15PO-1E0 > GuerbetC20-2 ΟΡΟ-1EO > GuerbetC12-32PO-3EO > C20+-30PO. Experiment 4: > Π NCNN CÜ N OR The maximum defoaming performance obtained by different dosage rates of C2030-20PO-1EO after a prolonged period of time was compared. Experimental Procedure: A 2000 mL aqueous solution containing 200 ppm of HC100C (foaming medium) was added to a recirculating foaming apparatus and circulated at room temperature to generate foam. Once the foam height reached 30 cm, the defoaming agent C2030-20PO-1EO was dosed at different concentrations (100, 200, 300, and 400 ppm) while the foaming solution was continuously circulated. The minimum foam height reached for each dosage was recorded, and the percentage foam reduction was calculated. It turns out that even at low dosage rates such as 100 ppm, the additives of the invention still exhibit superior performance. Experiment 5: The same experimental procedure as used for Experiment 4 was followed. Figure 8 compares the effectiveness of the defoaming behavior of the compounds of the invention with commercial samples at different temperatures after extended periods of time. As described in the experimental method, when no additional change in defoaming performance was observed, the > Π NCNN CÜ N The additive C2030-2ORO-1EO exhibited superior defoaming performance over a wide range of temperatures, compared to commercial additives. Experiment 6: The same experimental procedure as used for Experiment 4 was followed. Figure 7 illustrates the performance of an example of the compounds of the invention in various foaming media, compared to the performance of commercial samples. The C2030-20PO-1EO additive of the invention showed superior defoaming performance in conjunction with various foaming agents, when compared to commercial defoaming additives. Experiment 7; An antifoam test was performed to compare the antifoam potential of each additive and the deaeration abilities to remove trapped air by promoting liquid drainage from the lamella and bubble coalescence, resulting in faster foam decay. Experimental Procedure: An antifoam test was performed using the Krüss DFA100 and focused on comparing the antifoam and deaerating capabilities of the defoamer. The test was conducted by pouring 40 ml of nanopure water containing 2500 ppm of commercial foaming agent (C610-3.5EO sulfate) and 2500 ppm of > Π NCNN CÜ N A defoamer was placed in the glass column of the instrument. Air was then sprayed from the bottom through a filter plate with pore sizes ranging from 16–40 µm at a flow rate of 0.3 L / min. The spraying continued, and foam was generated for 2 minutes or until the foam reached the maximum height of the column (210 mm). The spraying was stopped, and the foam was allowed to decay for 15 minutes. The test was repeated for each defoamer as well as a control containing no defoamer. The defoamer capabilities of the 10 defoamers can be determined by comparing their maximum foam heights during the 2-minute spraying period (see Table 4). Comparing the foam decay rate as a function of foam half-life (see Figure 10) the time at which the foam volume has been reduced to 50% 15 for each defoamer tested also indicated its ability to aid in the drainage and coalescence of permanent foams. Table 4: Comparison of the maximum foam height achieved with various defoamers Defoamer Maximum foam height (mm) C2030-20PO—1EO 153.5 C1618-28PO-2EO 213.0 PDMS (Terminated in 213.1 OH) > Π NCNN CÜ N OR PPG-400 213.6 C1618-25PO-1EO 213.6 REFERENCE 214.4 Table 4 shows that C2030-20PO-1EO was the only additive observed to exhibit increased antifoaming properties. This was the only additive tested where the maximum foam height (153.5 mm) did not reach the foam height setpoint of 210 mm that triggered automatic foam cessation. The performance of the deaerator can be examined by comparing the foam decay rate as a function of the foam half-life, shown in Figure 8. The comparative deaerator performance of the additives is as follows: C2030-20PO-1EO > PDMS, terminated in OH > C1618-28PO-2EO > C1618-25PO-1EO > PPG-400. Experiment 8: Using the experimental procedure as described for Experiment 3, varying the number of PO and EO units, using the same hydrophobic agent, was used to compare each additive's ability to break down stable surface foam and act as a true defoamer by optimizing the PO / EO balance. Figure 9 shows a comparison of the foam height reduction after dosing each additive, respectively. The results show that the defoamer C203020PO-1EO performed best, but all defoamers were able to reduce foam to a significant degree. The preferred mole ratio of PO to mole ratio of EO is 5:14 to 3:1, with 14:1 being the most preferred, and 20:1 the most preferred. Experiment 9: Defoamers / antifoams perform well when they are ultra-dispersible in the feed. A small particle size improves the dispersibility of the defoamer / antifoam in aqueous feeds. Table 5 compares defoamers based on particle size. Table 5: Comparison of % foam reduction and average particle size of 15 Foam Reduction Average Particle Size (micron) Ci6-isOH-2 8ΡΟ / 2ΕΟ 28.14 67.8402 C2 0-30OH-3 5PO / 1EO 55.83 43.5514 C2o-3oOH-14PO / 1EO 71.1 13.2715 C20-30OH-20PO / IEO 79.93 3.9921 As can be observed, an alcohol alkoxylate or > Π Ν C Ν Ν The alcohol alkoxylate mixtures of the present invention have a smaller particle size than the defoamer of the prior art. The defoamer / antifoam of the present invention preferably has an average particle size less than 45 µm, more preferably less than 15 µm, and much more preferably less than 4 µm.

Claims

1. The use of an alcohol alkoxylate or a mixture of alcohol alkoxylates as a concentrated defoamer, antifoam and / or deaerator, characterized in that the alcohol alkoxylate or mixture of alcohol alkoxylates comprises at least: an alcohol alkoxylate, wherein the alcohol alkoxylate has a molecular structure as shown in [I]: RO-(CH2(CH3)CHO)m-(CH2CH2O)nH[I] wherein R is a branched and / or linear alkyl group having 20 to 50 carbon atoms, m = 10-40, and n = 0-5.

2. The use of alcohol alkoxylate or alcohol alkoxylate mixture according to claim 1, characterized in that R is a branched alkyl group.

3. The use of alcohol alkoxylate or alcohol alkoxylate mixture according to claim 1, characterized in that R is a linear alkyl group.

4. The use of alcohol alkoxylate or alcohol alkoxylate mixture according to any of claim 1 or 2, characterized in that R has 20 to 30 carbon atoms.

5. The use of alcohol alkoxylate or the mixture of > Π NCNNC Ü NU alcohol alkoxylate in accordance with any of the preceding claims, characterized in that m = 20 to 25 and η = 1 to 2 .

6. The use of alcohol alkoxylate or alcohol alkoxylate mixture according to any of the preceding claims, characterized in that the mole ratio of PO to mole ratio of EO is from 14:1 to 35:1, more preferably from 14:1 to 20:1 and much more preferably 20:

1.

7. The use of alcohol alkoxylate or alcohol alkoxylate mixture according to any of the preceding claims, characterized in that the alcohol alkoxylate has an average particle size less than 45pm, more preferably less than 15pm, and much more preferably less than 4qm.

8. The use of alcohol alkoxylate or alcohol alkoxylate mixture according to any of the preceding claims, characterized in that the alcohol alkoxylate or alcohol alkoxylate mixture is added at a concentration of between 50 ppm and 3,000 ppm, more preferably between 100 and 2,500 ppm, much more preferably between 100 and 500 ppm.

9. The use of alcohol alkoxylate or alcohol alkoxylate mixture in accordance with any of the preceding claims, characterized in that the temperature varies between 20 and 100°C, more preferably between 25 and 80°C.

10. The use of alcohol alkoxylate or alcohol alkoxylate mixture in accordance with any of the preceding claims, characterized in that no additional liquid or solid additives are added.

11. A method for defoaming an aqueous foam, the aqueous foam comprising an aqueous phase and a gas, the method characterized in that it comprises: providing a composition comprising at least: an alcohol alkoxylate, wherein the alcohol alkoxylate has a molecular structure as shown in [I]: RO-(CH2(CH3)CHO)m-(CH2CH2O)nH[I] wherein R is a branched and / or linear alkyl group having 20 to 50 carbon atoms, m = 10-40, n = 0-5, and contacting an aqueous foam with the composition whereby the aqueous foam collapses.

12. A method for preventing foaming in an aqueous material or deaerating an aqueous material, the method being characterized in that it comprises: providing a composition comprising at least: an alcohol alkoxylate, wherein the alcohol alkoxylate has a molecular structure as shown in [I]: RO-(CH2(CH3)CHO)m-(CH2CH2O)nH[1]>ϠNCNNCϋNAυ wherein R is a branched and / or linear alkyl group having 20 to 50 carbon atoms, m = 10-40, n = 0-5, and 5 contacting an aqueous material with the composition whereby (a) foam is prevented from forming in the aqueous material, (b) the aqueous material is deaerated, or both (a) and (b).