Alcohol Alkoxylate Mixtures as Concentrated Aqueous Defoamers

Abstract

The use of an alcohol alkoxylate or an alcohol alkoxylate mixture as a concentrated defoamer, antifoamer and/or deaerator wherein the alcohol alkoxylate or alcohol alkoxylate mixture comprises at least an alcohol alkoxylate, wherein the alcohol alkoxylate has a molecular structure as shown in [I]: R—O—(CH.sub.2(CH.sub.3)CHO).sub.m—(CH.sub.2CH.sub.2O).sub.n—H wherein R is a branched and/or linear alkyl group having from 20 to 50 carbon atoms, m=10-40, and n=0-5.

Claims

1. (canceled)

2. (canceled)

3. (canceled)

4. (canceled)

5. (canceled)

6. (canceled)

7. (canceled)

8. (canceled)

9. (canceled)

10. (canceled)

11. A method of defoaming an aqueous foam, said aqueous foam comprising an aqueous phase and a gas, said method comprising: providing a composition comprising at least: an alcohol alkoxylate, wherein said alcohol alkoxylate has a molecular structure as shown in [I]:
R—O—(CH2(CH3)CHO)m—(CH2CH2O)n—H  [I] wherein R is a branched and/or linear alkyl group having from 20 to 50 carbon atoms m=10−40, n=0−5, and contacting an aqueous foam with said composition whereby said aqueous foam collapses.

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

13. The method of claim 11 wherein R has 20 to 30 carbon atoms.

14. The method of claim 11 wherein m=20 to 25 and n=1 to 2.

15. The method of claim 11 wherein the ratio of moles of PO to moles of EO is from 14:1 to 35:1.

16. The method of claim 11 wherein the alcohol alkoxylate has an average particle size less than 45 μm.

17. The method of claim 11 wherein the alcohol alkoxylate is added in a concentration of between 50 ppm and 3000 ppm.

18. The method of claim 11 wherein the temperature ranges between 20 and 100° C.

19. The method of claim 11 wherein no additional additives, liquids or solids are added.

20. The method of claim 12 wherein R has 20 to 30 carbon atoms.

21. The method of claim 12 wherein m=20 to 25 and n=1 to 2.

22. The method of claim 12 wherein the ratio of moles of PO to moles of EO is from 14:1 to 35:1.

23. The method of claim 12 wherein the alcohol alkoxylate has an average particle size less than 45 μm.

24. The method of claim 12 wherein the alcohol alkoxylate is added in a concentration of between 50 ppm and 3000 ppm.

25. The method of claim 12 wherein the temperature ranges between 20 and 100° C.

26. The method of claim 12 wherein no additional additives, liquids or solids are added.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0023] FIG. 1 shows a comparison of foam height reduction after dosages of additives.

[0024] FIG. 2 shows a comparison of final foam heights after dosages of additives.

[0025] FIG. 3 shows the defoaming performance of various defoamers.

[0026] FIG. 4 shows the foam reduction achieved by various defoamers at a dosage of 500 ppm.

[0027] FIG. 5 shows the defoaming performance of C2030-20PO-1EO at various dosages.

[0028] FIG. 6 shows the defoaming performance of C2030-20PO-1EO at various temperatures.

[0029] FIG. 7 shows the performance of defoaming agents compared to commercial samples.

[0030] FIG. 8 shows the half-life for various defoamers.

[0031] FIG. 9 shows the performance of defoamers with various numbers of PO and EO units.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

[0032] The surfactants of the current 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 tailoring the hydrophobe structures of the compounds, together with the number of propylene oxide (PO) and/or ethylene oxide (EO) units, for a specific application area.

[0033] Materials

[0034] A number of surfactants, namely alkoxylated alcohols, were synthesized according to standard procedures (see Experimental section) and their properties characterized.

[0035] The materials used in various tests to determine efficiency of compounds as defoamers/antifoamers/deaerators are shown in Table 1:

TABLE-US-00001 TABLE 1 Materials used to evaluate defoaming/antifoaming/deaerating properties Number of Alcohol Number of ethylene carbon propylene oxide Alcohol Trade chain oxide units Name length Alcohol structure units (PO) (EO) ALFOL20.sup.+ C20-30 linear 35 5 ALFOL20.sup.+ C20-30 linear 35 1 ALFOL20.sup.+ C20-30 linear 35 0 ALFOL20.sup.+ C20-30 linear 20 1 ALFOL20.sup.+ C20-30 linear 19 2.5 ALFOL20.sup.+ C20-30 linear 19 0 ALFOL20.sup.+ C20-30 linear 14 5 ALFOL20.sup.+ C20-30 linear 14 1 ALFOL20.sup.+ C20-30 linear 14 0 UNILIN alcohol C20+ linear 30 0 Behenyl Alcohol C20-22 linear 20 1 ISOFOL12 C12 100% 2-alkyl 32 3 (Guerbet) branched (1.0 branch/molecule) ISOFOL20 C20 100% 2-alkyl 20 1 (Guerbet) branched (1.0 branch/molecule) SAFOL23 C24-26 50% branched 25 1 (2.16 branch/ molecule) ISOFOL32 C32 100% 2-alkyl 15 1 (Guerbet) branched (1.0 branch/molecule)

[0036] All examples represented by trade names above are marketed by Sasol Performance Chemicals, except UNILIN which was sourced from Baker Hughes.

[0037] Table 2 shows the commercial prior art defoamers that were used for comparative experiments.

TABLE-US-00002 TABLE 2 Defoamers used for comparative examples Alcohol Name Description Structure BASOPUR DF 5* C1618-28PO-2EO Linear EMULDAC 251 PE** C1618-25PO-1EO Linear PDMS (OH termi- Polydimethylsiloxane (MW = N/A nated) 550-3,200 Da) Carpel PGP 400*** Polypropylene glycol (PPG-400_ N/A Mol wt = 400 Da Polypropylene glycol (PPG-900) N/A Mol wt = 900 Da *Sold by BASF **Sold by Sasol Performance Chemicals ***Sold by Carpenter.

[0038] Table 3 lists the foamers that were used for the various defoaming experiments.

TABLE-US-00003 TABLE 3 Commercial foamers used for defoaming experiments NAME DESCRIPTION HF100C* C610-3.5EO Sulfate Coconut DEA Coconut diethanolamide CAPB Cocamidopropyl Betaine C.sub.12-16 APG C.sub.12-16 alkyl polyglycoside C.sub.12 LAS C.sub.12 linear alkylate sulfate *Available from Thatcher Chemicals

[0039] Experimental Section

[0040] Synthesis of alkoxylated (PO/EO) alcohols used for the experiments Alcohols ranging from C12-32 were propoxylated and ethoxylated utilizing wellknown alkoxylation catalysts such as double metal cyanide (DMC) or KOH catalysts. Each alcohol product was targeted to consist of between 10 to 40 moles of propylene oxide and 0-5 mole of ethylene oxide. The 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.

[0041] Experiment 1:

[0042] The first test parameters aimed to compare additives' ability to destroy stable surface foam and act as a true defoamer.

[0043] Experimental Procedure:

[0044] The foam reduction test was aimed at comparing each defoamer's ability to knockdown or destroy foam that has already been generated. The test was performed by pouring 40 ml of nanopure water containing 2500 ppm commercial foamer (0610-3.5EO Sulfate) into the glass column of the foam analyzer. The solution was stirred for 30 seconds at 8000 rpm to generate foam. Stirring was stopped, and the foam was allowed to stabilize for 1 minute. After 1 minute, initial foam height was recorded and defoamer was added to the foamed solution at 2500 ppm. The solution was stirred for 1 minute at 8000 rpm and stopped. The foam was allowed to stabilize for 30 seconds, and final foam height was recorded. The test was repeated for each of the defoamers. A blank was also performed utilizing the same procedure except no defoamer was added. The total percentage of foam reduction from initial foam height to final foam height was calculated for each defoamer (see FIG. 1). Final foam heights (see FIG. 2) were also compared for all defoamers and the blank.

[0045] FIGS. 1 and 2 show the defoamer performance decreases as follows: C2030-20PO-1EO>C1618-25PO-1EO>C1618-28PO-2EO>PDMS, OH terminated>PPG 400.

[0046] Experiment 2:

[0047] Experimental Procedure:

[0048] A 40 ml solution containing 2500 ppm of HF100C (610-3.5EO sulfate-AES) in DI-H.sub.2O was added to the Kruss foam analyzer and sparged with air at a rate of 0.2 L/min. through a bottom fritted disc with an average pore size of 100-160 μm. Once the foam height reached˜150 mm, while continuing the air sparge, 2500 ppm of defoamer was added to the solution. Sparging was continued until a total sparge time of 500 seconds had elapsed or the foam height had reached the maximum capacity of the Kruss instrument. This test allowed for evaluation of the amount of initial foam knock-down immediately following the addition of defoamer (defoaming) along with the defoamer's ability to maintain this initial knock-down over time (antifoaming).

[0049] FIG. 3 clearly illustrates the superior defoaming as well as antifoaming performance of an example of an inventive compound (C2030-20PO-1EO) over an extended period of time, when compared to commercial samples.

[0050] Experiment 3: The same experimental procedure as described for Experiment 1 was used. FIG. 4 compares foam height reduction after a 500 ppm dosage of various additives, respectively.

[0051] FIG. 4 shows the defoamer performance decreases as follows: C2030-20PO-1EO>(mixture of 50/50 wt % C2030-20PO-1EO/GuerbetC2426-25PO-1EO)>C2022-20PO-1EO>GuerbetC2426-25PO-1EO>GuerbetC32-15PO-1EO>GuerbetC20-20PO-1EO>GuerbetC12-32PO-3EO>C20+-30PO.

[0052] Experiment 4:

[0053] The maximum defoaming performance obtained by different dosage rates of C2030-20PO-1EO after the lapse of an extended time period was compared.

[0054] Experimental Procedure:

[0055] A 2000 ml aqueous solution containing 2 500 ppm of HC100C (foaming medium) was added to a recirculating foaming apparatus and circulated at room temperature to generate foam. Once the foam height reach 30 cm, the defoamer C2030-20PO-1EO was dosed at different concentrations (100, 200, 300 and 400 ppm) while continuously circulating the foaming solution. The minimum foam height reached for each dosage was recorded and the % foam reduction calculated.

[0056] It follows that even at low dosage rates as 100 ppm, the invention's additives still exhibit superior performance.

[0057] Experiment 5:

[0058] The same experimental procedure as used for Experiment 4 was followed. FIG. 8 compares the effectiveness of defoaming behavior of the invention's compounds to commercial samples at different temperatures after extended time periods.

[0059] As described in the experimental method, when no additional change in defoaming performance were observed. the 02030-20PO-1EO additive exhibited superior defoaming performance over a wide range of temperatures, compared to commercial additives.

[0060] Experiment 6:

[0061] The same experimental procedure as used for Experiment 4 was followed. FIG. 7 illustrates the performance of an example of the invention's compounds in various foaming mediums, compared to the performance of commercial samples.

[0062] The invention's C2030-20PO-1EO additive showed superior defoaming behavior together with various foamers, when compared to commercial defoaming additives.

[0063] Experiment 7:

[0064] An antifoaming test was performed to compare each additive's antifoaming potential and deaerating abilities to remove entrapped air by promoting liquid drainage from the lamella and bubble coalescence resulting in faster foam decay.

[0065] Experimental Procedure:

[0066] An antifoaming test was performed with the Krüss DFA100 and was aimed at comparing each of the defoamer's antifoaming and deaerating abilities. The test was performed by pouring 40 mL of nanopure water containing 2500 ppm commercial foamer (C610-3.5EO sulfate) and 2500 ppm defoamer into the instrument's glass column. Air was then sparged from the bottom through a filter plate with pore sizes ranging from 16-40 μm at a flow rate of 0.3 L/min. Sparging was continued and foam was generated for 2 minutes or until the foam reached the maximum height of the column (210 mm). Sparging was stopped, and the foam was allowed to decay for 15 minutes. The test was repeated for each defoamer as well as a blank that contained no defoamer. The defoamers' antifoaming abilities can be determined by comparing their maximum foam heights during the 2 minute sparging period (see Table 4). Comparing the rate of foam decay as a function of foam half-life (see FIG. 10), the time at which foam volume has reduced to 50% for each defoamer tested also indicated its ability at aiding in the drainage and coalescence of standing foams.

TABLE-US-00004 TABLE 4 Comparison of the maximum foam height reached with various 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 BLANK 214.4

[0067] Table 4 shows that C2030-20PO-1EO was the only observable additive to exhibit enhanced antifoaming properties. It was the only additive tested where the maximum foam height (153.5 mm) did not reach the 210 mm foam height set point which triggered an automatic shutdown of foam formation.

[0068] Deaerator performance can be examined by comparing the rate of foam decay as a function of foam half-life, shown in FIG. 8.

[0069] Comparative deaerator performance of the additives is as follows: C2030-20PO-1EO>PDMS, OH terminated>C1618-28PO-2EO>C1618-25PO-1EO>PPG-400.

[0070] Experiment 8:

[0071] Using the experimental procedure as described for Experiment 3, variation of the number of PO and EO units, using the same hydrophobe, aimed to compare each additive's ability to destroy stable surface foam and to act as a true defoamer by optimizing the PO/EO balance. FIG. 9 depicts a comparison of foam height reduction after dosage of each additive, respectively.

[0072] The results show that the defoamer 02030-20PO-1EO performed the best, but all defoamers were able to reduce the foam to a significant extent. The ratio of moles of PO to moles of EO is preferably from 14:1 to 35:1, more preferably from 14:1 to 20:1, and most preferably 20:1.

[0073] Experiment 9:

[0074] Defoamers/antifoamers perform well when they are ultra-dispersible in the feed. Low particle size improves the dispersibility of the defoamer/antifoamer in the aqueous feeds. Table 5 compares the defoamers based on particle size.

TABLE-US-00005 TABLE 5 Comparison of the % foam reduction and average particle size. Foam Re- Avg. Particle Size Defoamer duction (micron) C.sub.16-18OH-28PO/2EO 28.14 67.8402 C.sub.20-30OH-35PO/1EO 55.83 43.5514 C.sub.20-30OH-14PO/1EO 71.1 13.2715 C.sub.20-30OH-20PO/1EO 79.93 3.9921

[0075] As can be seen, the alcohol alkoxylate or alcohol alkoxylate mixture of the present invention has a lower particle size than the prior art defoamer. The defoamer/antifoamer of the present invention preferably has an average particle size less than 45 μm, more preferably less than 15 μm, and most preferably less than 4 μm.