RU2822066C2 - Mixtures of alkoxylates of alcohols as concentrated aqueous antifoaming agents - Google Patents

Abstract

FIELD: chemistry.

SUBSTANCE: group of inventions relates to alcohol alkoxylates or mixtures thereof and use of alcohol alkoxylates or mixtures thereof as concentrated aqueous defoamers, antifoaming agents and/or deaerators. Declared is the use of an alcohol alkoxylate or a mixture containing an alcohol alkoxylate as a concentrated antifoaming agent, a defoamer and a deaerator. Alcohol alkoxylate or alcohol alkoxylate-containing mixture contains at least an alcohol alkoxylate having the following molecular structure (I): R-O-(CH2(CH3)CHO)m-(CH2CH2O)n-H (I), where R denotes a branched and/or linear alkyl group containing from 20 to 50 carbon atoms, m = 10–40 and n = 0–5, where the alcohol alkoxylate is characterized by an average particle size of less than 45 mcm. Alcohol alkoxylate is added in concentration of 50 ppm to 3000 ppm. Also disclosed are methods of breaking down water foam, preventing foaming in water material and deaeration of water material.

EFFECT: group of inventions provides effective destruction of foam, prevention of foam formation and deaeration of water material present in various chemical, domestic, and industrial processes.

15 cl, 9 dwg, 5 tbl, 9 ex

Description

The present invention relates to alcohol alkoxylates or mixtures thereof and the use of alcohol alkoxylates or mixtures thereof as concentrated aqueous defoamers, defoamers and/or deaerator agents. More specifically, alcohol alkoxylates are linear, long-chain alcohol alkoxylates intended for use as antifoam, foam breakage, and deaeration additives in a variety of applications.

BACKGROUND OF THE ART

In various industrial processes, the appearance of foam creates a difficult environment, which, for example, can have a negative impact on the reaction rate and, in general, prevent normal optimal functioning. Existing methods for controlling foam include mechanical means such as the use of baffles and mixing control systems. Chemical defoamers or antifoams are often used in combination with them. There are different classes of additives used for foam control, foam control, and foam mitigation, with different mechanisms of action that are effective for different types of foam (e.g., macro or micro foam). Although these classes are different in principle, the terms used to define them are often used interchangeably. In addition, many, if not most, additives perform more than one function.

Antifoams are additives that prevent or retard the formation of foam from the start; they are usually added to a potentially foaming solution until foam forms. Defoamers are compounds that are added to mixtures to break up foam that has already formed, they are designed to quickly break down surface foam (macro-foam). Deaerators function similarly to defoamers, also designed to destroy already formed foam, but are aimed at subsurface foam (micropoam).

Well-known defoamers, defoamers and defoamers include, but are not limited to, silicone oils as well as block copolymers of lower alkylene glycols. US 6,534,550 describes antifoam compositions containing alcohols, alcohol alkoxylates, emulsifiers and water to prevent or retard the formation of foam in aqueous systems. The compositions described in US 6,534,550 are emulsions that require precise mixing of a number of different components to function properly. US 6,562,875 describes the use of alkoxylated alcohols in combination with emulsifiers such as anionic surfactants as antifoam agents in the pulp and paper industry. All prior art documents cited are incorporated herein by reference for all purposes.

However, there continues to be a need for stable, simple, inexpensive aqueous defoamers, defoamers and/or de-aerators in concentrated form that can be effectively used in the chemical industry, household and industrial processes.

PURPOSE OF THE INVENTION

An advantage of the compounds or mixtures of compounds according to the invention and their use in aqueous systems is the provision of concentrated surfactants with an ultra-fine particle size. Due to the nature of the specific alcohol alkoxylates described, they are insoluble but highly dispersible surfactants suitable for effective foam breaking, foam prevention and deaeration of aqueous feedstocks present in a variety of chemical, domestic and industrial processes.

SUMMARY OF THE INVENTION

The present invention relates to a series of alcohol alkoxylates and their use as defoamers, defoamers and/or deaerators for aqueous phases in various applications. These include general applications for foam breaking, foam control and deaeration, such as, but not limited to, oil and gas, agriculture, water treatment, and process industries such as pulp and paper, fermentation, detergents, fluids for metalworking, paint and coating, emulsion polymerization and construction.

The present invention, in particular, provides the use of an alcohol alkoxylate or an alcohol alkoxylate-containing mixture as a concentrated defoamer, antifoaming agent and/or deaerator, wherein the alcohol alkoxylate or an alcohol alkoxylate-containing mixture contains at least an alcohol alkoxylate, wherein the alcohol alkoxylate has the following molecular structure (I):

R-O-(CH2(CH3)CHO)m-(CH2CH2O)n-H (I)

where R denotes a branched and/or linear alkyl group containing from 20 to 50 carbon atoms, preferably from 20 to 30 carbon atoms,

m=10-40, preferably 20-25

n=0-5, preferably 1-2.

The ratio of the number of moles of PO to the number of moles of EO is preferably from 14:1 to 35:1, more preferably from 14:1 to 20:1, most preferably 20:1.

A distinctive feature of the invention, among others, is the very small dosage required during use. The alcohol alkoxylate or alcohol alkoxylate-containing mixture is added at a concentration of from 50 ppm to 3000 ppm, more preferably from 100 to 2500 ppm, most preferably from 100 to 500 ppm.

The compounds described in the present invention are characterized by sufficient chemical and thermal stability. Their use temperature may range from 20 to 100°C, more preferably from 20 to 80°C.

In addition, the described alcohol alkoxylates are characterized by high efficiency of destruction, prevention of foam formation and deaeration in concentrated form and are highly active. The use of an alcohol alkoxylate or an alcohol alkoxylate-containing mixture is most advantageous when other additives, liquid or solid, such as emulsifiers, solvents and carriers are not available.

Additional advantages of the compounds of the present invention, among others, are that they are silicone-free, non-explosive, non-flammable, salt-resistant and non-corrosive.

The invention also relates to a method for destroying foam and/or deaerating and/or preventing the formation of aqueous foam, wherein the aqueous foam contains an aqueous phase and a gas, and the method includes the stages of:

i) provide a composition containing at least:

alcohol alkoxylate, wherein the alcohol alkoxylate has the following molecular structure (I):

R-O-(CH2(CH3)CHO)m-(CH2CH2O)n-H (I)

where R denotes a branched and/or linear alkyl group containing from 20 to 50 carbon atoms, preferably from 20 to 30 carbon atoms, m=10-40, preferably 20-25, n=0-5, preferably 1- 2, and

ii) bringing said aqueous foam into contact with said composition, wherein said aqueous foam is destroyed.

The alcohol alkoxylate or alcohol alkoxylate-containing mixture of the present invention preferably has an average particle size of less than 45 microns, more preferably less than 15 microns, most preferably less than 4 microns. The small particle size helps improve the dispersibility of the defoamer/antifoam in aqueous feeds, providing dispersible compounds that require minimal mixing.

In contrast to the prior art, the present invention provides a concentrated defoamer that does not require emulsifiers or the like to break down/prevent foam formation.

BRIEF DESCRIPTION OF THE DRAWINGS

In fig. 1 presents comparative results of reducing the foam height after dosing additives.

In fig. 2 presents comparative results of the final foam height after dosing additives.

In fig. Figure 3 shows the effectiveness of foam destruction by various defoamers.

In fig. Figure 4 shows the reduction in foam height achieved by various defoamers at a dosage of 500 ppm.

In fig. Figure 5 shows the destruction efficiency of C2030-20P0-1EO foam at various dosages.

In fig. Figure 6 shows the destruction efficiency of C2030-20P0-1EO foam at different temperatures.

In fig. Figure 7 shows the effectiveness of defoamers in comparison with commercially produced samples.

In fig. Figure 8 shows the half-life of various antifoam agents.

In fig. Figure 9 shows the effectiveness of defoamers with different numbers of PO and EO units.

DETAILED DESCRIPTION OF THE PREFERRED OPTIONS FOR CARRYING OUT THE INVENTION

The surfactant compositions of the present invention are effective defoamers, defoamers and deaerator for a wide range of aqueous phases. Optimal performance of the compositions can be achieved by adapting the hydrophobic structure of the compounds, as well as the number of propylene oxide (PO) and/or ethylene oxide (EO) units, to the specific application.

Materials

A number of surfactants, namely alkoxylated alcohols, were synthesized in accordance with standard methods (see Experimental section), and their properties were studied.

The materials used in the various tests to determine the effectiveness of the compounds as defoamers/antifoamers/deaerator agents are given in Table 1:

Table 1. Materials used to evaluate the properties of defoamers/antifoams/deaerator

Brand of alcohol Alcohol carbon chain length Alcohol structure Number of propylene oxide (PO) units Number of ethylene oxide units (EO) ALFOL20 ⁺ C20-30 Linear 35 5 ALFOL20 ⁺ C20-30 Linear 35 1 ALFOL20 ⁺ C20-30 Linear 35 0 ALFOL20 ⁺ 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 Alcohol UNILIN C20+ Linear thirty 0 Behenyl alcohol C20-22 Linear 20 1 ISOFOL12 C12 (Gerbe) 100% 2-alkyl branched
1.0 branch per molecule 32 3 ISOFOL20 C20 (Gerbe) 100% 2-alkyl branched
1.0 branch per molecule 20 1 SAFOL23 C24-26 50% 2-alkyl branched
2.16 branches per molecule 25 1 ISOFOL32 C32 (Gerbe) 100% 2-alkyl branched
1.0 branch per molecule 15 1

All examples presented above under brand names are marketed by Sasol Performance Chemicals with the exception of UNILIN alcohol from Baker Hughes.

Table 2 shows the commercially available defoamers of the prior art used in the comparative examples.

Table 2. Defoamers Used in Comparative Examples

Name Description Alcohol structure BASOPUR DF 5* C1618-28PO-2EO Linear EMULDAC 251 PE** C1618-25PO-1EO Linear PDMS (OH-terminated) Polydimethylsiloxane Mol. weight = 550-3200 Yes no data Carpol PGP 400*** Polypropylene glycol PPG-400, Mol. weight = 400 Yes no data Polypropylene glycol PPG-900, Mol. weight = 900 Yes no data

* Sold by BASF.

** Sold by Sasol Performance Chemicals.

***Sold by Carpenter.

Table 3 lists the foaming agents used in the various foam breakdown experiments.

Table 3. Commercially produced foaming agents used in foam destruction experiments

Name Description HF100C* C610-3.5EO sulfate Coconut DEA Coconut diethanolamide CAPB Cocamidopropyl betaine C _12-16 APG C _12-16 alkyl polyglycoside C ₁₂ LAS C ₁₂ linear alkylate sulfate

* From Thatcher Chemicals.

EXPERIMENTAL PART

Synthesis of alkoxylated (PO/EO) alcohols used in experiments

C12-32 alcohols have been propoxylated and ethoxylated using well known catalysts such as double metal cyanide (DMC) or KOH. Each resulting alcohol had to contain from 10 to 40 moles of propylene oxide and 0-5 moles of ethylene oxide. Samples were prepared in a 600 mL Parr reactor using an alkoxylation catalyst of choice. Each alcohol was propoxylated using purified propylene oxide at 130-150°C and 40-60 psig. (psig) (275.8-413.7 kPa), followed by ethoxylation using purified ethylene oxide at 150-160°C and 40-60 psig (275.8-413.7 kPa) in one continuous pass.

Experiment 1

The parameters examined in the first test compared the additives' ability to break down stubborn surface foam and act as a true defoamer.

Experimental technique

Foam breaking tests were designed to compare the ability of each defoamer to break down existing foam. Tests were performed by pouring 40 ml of high purity water containing 2500 ppm of a commercially available foaming agent (C610-3.5EO sulfate) into the glass column of a foam analyzer. The solution was stirred for 30 sec at 8000 rpm to create foam. Stirring was stopped, and the foam was allowed to stabilize for 1 minute. After 1 minute, the initial foam height was recorded and antifoam was added to the foam solution at 2500 ppm. The solution was stirred for 1 min at 8000 rpm, and the stirring was stopped. The foam was allowed to stabilize for 30 seconds, and the final height of the foam was recorded. The test was repeated with each defoamer. A control test was also conducted using the same procedure except that no antifoam was added. For each defoamer, the total percentage reduction in the final foam height relative to the initial height was calculated (see Fig. 1). The final foam height (see Fig. 2) was also compared for all defoamers and the control sample.

In fig. 1 and 2 show that the effectiveness of the defoamer decreases as follows: C2030-20PO-1EO > C1618-25PO-1EO > C1618-28PO-2EO > OH-terminated PDMS > PPG 400.

Experiment 2

Experimental technique

40 ml of a solution containing 2500 ppm HF100C (610-3.5EO sulfate - AES) in deionized H ₂ O was introduced into a Kruss foam analyzer and air was bubbled at a flow rate of 0.2 L/min through a bottom fritted disk with an average pore size of 100- 160 microns. When the foam height reached ~150mm, while air bubbling continued, 250 ppm of defoamer was added to the solution. Sparging was continued until a total sparging time of 500 seconds was reached or until the foam height reached the maximum capacity of the Kruss device. This test quantified the breakdown of foam immediately after the addition of the defoamer (defoaming), as well as the ability of the defoamer to maintain this state over time (antifoaming).

In fig. 3 clearly demonstrates the high efficiency of foam destruction, as well as the prevention of foam formation, with one exemplary compound corresponding to the invention (C2030-20PO-1EO) over a long period of time compared to samples of commercially produced compounds.

Experiment 3

The same experimental procedure was used as in Example 1. In FIG. 4 compares the reduction in foam height after adding 500 ppm of different additives, respectively.

In fig. 4 shows that the effectiveness of the defoamer is reduced as follows: C2030-20PO-1EO> (50/50 wt% mixture of C2030-20PO-1EO/C2426-25PO-1EO Gerbe)> C2022-20PO-1EO> C2426-25PO-1EO Gerbe > C32-15PO-1EO Gerbe> C20-20PO-1EO Gerbe> C12-32PO-3EO Gerbe> C20+-30PO.

Experiment 4

A comparison was made of the maximum foam destruction efficiency achieved with different dosages of C2030-20-PO-1EO after a long period of time.

Experimental technique

2000 ml of an aqueous solution containing 2500 ppm HC100C (foaming medium) was introduced into a recirculating foam apparatus and circulated at room temperature to create foam. When the foam height reached 30 cm, C2030-20PO-1EO defoamer was dosed at different concentrations (100, 200, 300 and 400 ppm with continuous circulation of the foam solution. The minimum foam height achieved at each concentration was recorded and the percentage destruction was calculated foam.

It has been found that even at a dosage as low as 100 ppm, the additives according to the invention are highly effective.

Experiment 5

The same experimental procedure was used as in Experiment 4. In FIG. 6 compares the foam destruction efficiency of compounds according to the invention and commercially produced samples at different temperatures after a long period of time.

As described in the experimental procedure, when no additional change in foam breakdown efficiency was observed, the C2030-20PO-1EO additive exhibited high foam breakdown efficiency over a wide temperature range compared to commercial additives.

Experiment 6

The same experimental procedure was used as in Experiment 4. In FIG. 7 shows the effectiveness of an exemplary inventive compound in various foaming media compared to the effectiveness of commercially available samples.

The additive C2030-20PO-1EO corresponding to the invention was characterized by high efficiency in destroying foam with different foaming agents compared to commercially produced defoaming additives.

Experiment 7

A foam control test was conducted to compare each additive's inherent foam control potential and ability to deaerate by removing trapped air through enhanced thin layer liquid drainage and bubble coalescence resulting in faster foam breakdown.

Experimental technique

Foam prevention test was carried out using Krüss DFA100; it aimed to compare the foam control and air release capabilities of each defoamer. The test was carried out by pouring 40 ml of high purity water containing 2500 ppm commercially available foaming agent (C610-3.5EO sulfate) and 2500 ppm defoamer into the glass column of the foam analyzer. Then, air was bubbled through a bottom filter plate with an average pore size of 16–40 μm at a flow rate of 0.3 l/min. Sparging was continued to create foam for 2 min or until the foam reached the maximum column height (210 mm). The bubbling was stopped, and the foam was left to break down for 15 minutes. The test was repeated with each defoamer, and a control test without the defoamer was also performed. The ability of defoamers to prevent foam formation could be determined by comparing the maximum foam height during the 2 min sparging period (see Table 4). Comparison of the rate of foam breakdown as a function of foam half-life (see FIG. 10), the time it takes for foam volume to decrease by 50%, for each defoamer tested also indicated its ability to improve drainage and coalescence of stationary foam.

Table 4. Comparison of maximum foam height achieved with different defoamers

Defoamer Maximum foam height (mm) C2030‐20PO‐1EO 153.5 C1618-28PO-2EO 213.0 PDMS (OH-terminated) 213.1 PPG-400 213.6 C1618-25PO-1EO 213.6 Control test 214.4

Table 4 shows that C2030-20PO-1EO was the only additive observed that had an increased ability to prevent foaming. It was the only additive tested where the maximum foam height (153.5 mm) did not reach the foam height target of 210 mm at which automatic foam stop was triggered.

Deaeration capacity can be established by comparing the rate of foam breakdown as a function of the foam half-life shown in FIG. 8.

The comparative additive deaeration efficiencies were as follows: C2030-20PO-1EO > OH-terminated PDMS > C1618-28PO-2EO > C1618-25PO-1EO > PPG-400.

Experiment 8

Using the methodology described for Experiment 3, varying the number of PO and EO units using the same hydrophobic substance was aimed at comparing the ability of each additive to break down persistent surface foam and act as a true defoamer by optimizing the PO/EO balance. In fig. 9 shows a comparison of the reduction in foam height after dosing each additive, respectively.

The results show that the defoamer C2030-20PO-1EO was the most effective, however, all defoamers were able to significantly reduce foam height. The ratio of the number of moles of PO to the number of moles of EO is preferably from 14:1 to 35:1, more preferably from 14:1 to 20:1, most preferably 20:1.

Experiment 9

Defoamers/antifoams are effective when they are very well dispersed in the raw material. The small particle size helps to increase the dispersibility of the defoamer/antifoam in aqueous feedstock. Table 5 compares defoamers based on particle size.

Table 5. Comparison of % foam breakdown and average particle size

Defoamer % foam destruction Average particle size (µm) C16-18OH-28PO/2EO 28.14 67.8402 C20-30OH-35PO/1EO 55.83 43.5514 C20-30OH-14PO/1EO 71.1 13.2715 C20-30OH-20PO/1EO 79.93 3.9921

The alcohol alkoxylate or alcohol alkoxylate-containing mixture of the present invention has been shown to have a smaller particle size than the prior art defoamer. The defoamer/antifoam agent of the present invention preferably has an average particle size of less than 45 microns, more preferably less than 15 microns, most preferably less than 4 microns.

Claims (63)

1. The use of an alcohol alkoxylate or a mixture containing an alcohol alkoxylate as a concentrated defoamer, wherein the alcohol alkoxylate or a mixture containing an alcohol alkoxylate contains at least: an alcohol alkoxylate, wherein said alcohol alkoxylate has the following molecular structure (I): R-O-(CH2(CH3)CHO)m-(CH2CH2O)n-H (I), where R denotes a branched and/or linear alkyl group containing from 20 to 50 carbon atoms, m=10-40, and n=0-5, wherein the alcohol alkoxylate has an average particle size of less than 45 microns, and wherein the alcohol alkoxylate is added at a concentration of from 50 ppm to 3000 ppm. 2. Use of an alcohol alkoxylate or an alcohol alkoxylate-containing mixture according to claim 1, wherein R is a branched alkyl group. 3. Use of an alcohol alkoxylate or an alcohol alkoxylate-containing mixture according to claim 1, wherein R is a linear alkyl group. 4. Use of an alcohol alkoxylate or an alcohol alkoxylate-containing mixture according to any one of claims 1 or 2, wherein R contains from 20 to 30 carbon atoms. 5. Use of an alcohol alkoxylate or an alcohol alkoxylate-containing mixture according to any one of the preceding claims, in which m=20 to 25 and n=1 to 2. 6. Use of an alcohol alkoxylate or an alcohol alkoxylate-containing mixture according to any one of the preceding claims, wherein the ratio of the number of moles of PO to the number of moles of EO is from 14:1 to 35:1, more preferably from 14:1 to 20:1, most preferably 20 :1. 7. Use of an alcohol alkoxylate or an alcohol alkoxylate-containing mixture according to any one of the preceding claims, wherein the alcohol alkoxylate has an average particle size of less than 15 microns, most preferably less than 4 microns. 8. Use of the alcohol alkoxylate or alcohol alkoxylate-containing mixture according to any one of the preceding claims, wherein the alcohol alkoxylate or alcohol alkoxylate-containing mixture is added at a concentration of 100 to 2500 ppm, more preferably 100 to 500 ppm. 9. Use of an alcohol alkoxylate or an alcohol alkoxylate-containing mixture according to any one of the preceding claims, wherein the temperature is in the range of 20 to 100°C, more preferably 25 to 80°C. 10. The use of an alcohol alkoxylate or a mixture containing an alcohol alkoxylate according to any of the preceding paragraphs, without introducing additional additives, liquid or solid. 11. The use of an alcohol alkoxylate or a mixture containing an alcohol alkoxylate as an antifoam agent, wherein the alcohol alkoxylate or a mixture containing an alcohol alkoxylate contains at least: an alcohol alkoxylate, wherein said alcohol alkoxylate has the following molecular structure (I): R-O-(CH2(CH3)CHO)m-(CH2CH2O)n-H (I), where R denotes a branched and/or linear alkyl group containing from 20 to 50 carbon atoms, m=10-40, and n=0-5, wherein the alcohol alkoxylate has an average particle size of less than 45 microns, and wherein the alcohol alkoxylate is added at a concentration of from 50 ppm to 3000 ppm. 12. The use of an alcohol alkoxylate or a mixture containing an alcohol alkoxylate as a deaerator, wherein the alcohol alkoxylate or a mixture containing an alcohol alkoxylate contains at least: an alcohol alkoxylate, wherein said alcohol alkoxylate has the following molecular structure (I): R-O-(CH2(CH3)CHO)m-(CH2CH2O)n-H (I), where R denotes a branched and/or linear alkyl group containing from 20 to 50 carbon atoms, m=10-40, and n=0-5, wherein the alcohol alkoxylate has an average particle size of less than 45 microns, and wherein the alcohol alkoxylate is added at a concentration of from 50 ppm to 3000 ppm. 13. A method for destroying aqueous foam, wherein said aqueous foam contains an aqueous phase and a gas, wherein said method includes the stages of: provide a composition containing at least: an alcohol alkoxylate, wherein said alcohol alkoxylate has the following molecular structure (I): R-O-(CH2(CH3)CHO)m-(CH2CH2O)n-H (I), where R denotes a branched and/or linear alkyl group containing from 20 to 50 carbon atoms, m=10-40, n=0-5, wherein the alcohol alkoxylate has an average particle size of less than 45 microns, and wherein the alcohol alkoxylate is added at a concentration of from 50 ppm to 3000 ppm, and bringing the aqueous foam into contact with said composition, wherein said aqueous foam is destroyed. 14. A method for preventing foaming in an aqueous material, said method comprising the steps of: provide a composition containing at least: an alcohol alkoxylate, wherein said alcohol alkoxylate has the following molecular structure (I): R-O-(CH2(CH3)CHO)m-(CH2CH2O)n-H (I), where R denotes a branched and/or linear alkyl group containing from 20 to 50 carbon atoms, m=10-40, n=0-5, wherein the alcohol alkoxylate has an average particle size of less than 45 microns, and wherein the alcohol alkoxylate is added at a concentration of from 50 ppm to 3000 ppm, and bringing the aqueous material into contact with said composition, wherein (a) said aqueous material is prevented from forming foam, (b) said aqueous material is deaerated, or both (a) and (b). 15. A method for deaerating an aqueous material, wherein said method includes the stages of: provide a composition containing at least: an alcohol alkoxylate, wherein said alcohol alkoxylate has the following molecular structure (I): R-O-(CH2(CH3)CHO)m-(CH2CH2O)n-H (I), where R denotes a branched and/or linear alkyl group containing from 20 to 50 carbon atoms, m=10-40, n=0-5, wherein the alcohol alkoxylate has an average particle size of less than 45 microns, and wherein the alcohol alkoxylate is added at a concentration of from 50 ppm to 3000 ppm, and bringing the aqueous material into contact with said composition, wherein (a) said aqueous material is prevented from forming foam, (b) said aqueous material is deaerated, or both (a) and (b).