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(11) | EP 0 213 054 B1 |
| (12) | EUROPEAN PATENT SPECIFICATION |
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Alkaline tolerant sulfobetaine amphoteric surfactants Alkaliverträgliche amphoterische Sulfobetain-Tenside Sulfobétaines amphotères, tensioactives, résistantes aux alcalis |
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| Note: Within nine months from the publication of the mention of the grant of the European patent, any person may give notice to the European Patent Office of opposition to the European patent granted. Notice of opposition shall be filed in a written reasoned statement. It shall not be deemed to have been filed until the opposition fee has been paid. (Art. 99(1) European Patent Convention). |
[0001] The present invention concerns an aqueous basic solution of a base, water and betaine according to the introductory portion of claim 1 and a method for making a storage stable aqueous basic solution according to the introductory portion of claim 11.
[0002] In a variety of cleaning and other chemical uses, use of strong basic aqueous solutions is required. Since many of these cleaning and other chemical uses also require the basic solution to exhibit surfactancy, a need exists for surface active agents or surfactants which exhibit their surface active properties when contained in strongly basic aqueous solutions.
[0003] As an additional property, such surfactants in a strongly basic alkaline solution should display very low to moderate foaming characteristics. Thus, an unusual combination of constraints are placed upon a surfactant in order to satisfy such criteria.
[0004] The class of surfactants used in the present invention are soluble in strongly basic alkaline solutions, are storage stable for extended time periods of storage in strongly basic alkaline solutions, and are very low to moderate foamers. Moreover, such surfactants retain their surfactant properties when incorporated into strongly basic aqueous solutions. The surfactants which possess such unique combination of properties are alkyl sulfobetaines wherein the alkyl group ranges from about 6 to 12 carbon atoms in chain length. Another aspect of the present invention is an aqueous solution of the alkyl sulfobetaine and a base, such as, for examples, sodium hydroxide or potassium hydroxide in concentrations ranging up to 30%-50% in concentration.
[0005] Advantages of the present invention include an amphoteric surfactant which is soluble in water and which is soluble and storage stable in an aqueous basic solution. A further advantage is that the amphoteric surfactant retains its surfactant properties in an aqueous basic solution. Yet another advantage is that the amphoteric surfactant is stable in strongly basic aqueous solutions. These and other advantages will be readily apparent to those skilled in the art based upon the disclosure contained herein.
[0006] Sulphobetaines are known in the art and are described in the GB-A 2 081 259, GB-A 1 419 097, GB-A 1 037 647 and US-A 3 280 179.
[0007] The aqueous basic solution of the present invention is defined according to the characterized portion of claim 1 and the method of making a storage stable aqueous basic solution of the present invention is defined according to the characterizing portion of claim 11.
[0008] The amphoteric sulfobetaine surfactants used in the present invention are unique in their ability to meet diverse criteria required of them in formulating aqueous basic surfactant solutions.
[0009] The sulfobetaines used in the present invention can be represented conventionally by the following general structure:
[0010] Where R1 is a Cs-C12 alkyl group;
R2 and Rs are a methyl group, a 2-hydroxy ethyl group, or a 2-hydroxy propyl group; and
R4 is H or OH.
[0011] Within the alkyl group range of Cs-C12 the sulfobetaine possesses the requisite degree of water solubility and surfactancy required of it. While various reaction schemes may be envisioned for synthesis of the alkyl sulfobetaines of the present invention, the following two-step reaction scheme currently is favoured where R4 is OH. The initial step involves the formation of an epichlorhydrin/-bisulfite intermediate. This reaction conveniently is conducted in water in the presence of a base (for example, sodium hydroxide) at relatively moderate reaction temperature (e.g. 49°-93°C (120°-200°F)) and preferably under inert atmosphere.
[0012] Following the formation of the epichlorhydrin/bisulfite intermediate, such intermediate is reacted with the appropriate amine for forming the product sulfobetaine. This second reaction step is conducted at reaction temperatures ranging from 37.8°C to 93°C (100° to 200°F). Unreacted material then can be neutralized and/or removed and the pH and percent non-volatile solids of the reaction product adjusted as is necessary, desirable, or convenient in conventional fashion. For sulfobetaine where R4 is H, a propyl sulfone,
is reacted with the appropriate amine. The resulting alkyl sulfobetaine is soluble in caustic solution at concentrations ranging up to 10% by weight and greater. Moreover, such solubility is present even at elevated levels of potassium hydroxide, sodium hydroxide, or like bases ranging in concentrations of greater than 30%, advantageously 30%-50%, and preferably 40%-50%.
[0013] A variety of bases may be used in conjunction with the sulfobetaines of the present invention. Such bases include, for example, sodium hydroxyde, potassium hydroxide, calcium hydroxide, calcium oxide, sodium metasilicate, tetrapotassium pyrophosphate, sodium tripolyphosphate, trisodium phosphate, potassium silicate, and the like, and even mixtures thereof. As the Example will demonstrate, the alkyl dimethyl hydroxy sulfobetaines user in the present invention are stable in potassium hydroxide and sodium hydroxide solutions ranging up to 40-50 percent concentration.
[0014] The aqueous basic solutions of sulfobetaines of the present invention find use in a variety of applications. Such applications include, for example, bottle washing compounds, hot vat cleaning compounds, paper pulping, paint strippers, railroad and aircraft cleaners, dairy and food plant cleaners, detergent sanitizers, polymer-based wax strippers, and the like. The excellent stability, surfactancy, and low foaming characteristics of the alkyl dimethyl sulfobetaine caustic solutions make them useful in these and a variety of additional applications.
[0015] The following Example shows how the present invention can be practiced but should not be construed as limiting. All percentages and proportions are by weight in this application unless otherwise expressly indicated.
EXAMPLES
EXAMPLE 1
[0016] Lauryldimethy sulfobetaine (R4 = OH) was made by a two-step process described herein. The first step involved the charging of a small Parr reactor with sodium bisulfite (242 g), epichlorhydrin (228 g), deionized water (910 g), and solid sodium hydroxide (2 g). The water and base were mixed and nitrogen sparged to remove dissolved oxygen prior to charging the reactor. The reactor was pressurized to 0.14 MPa (20 psi) with nitrogen and heated to 53°C (125°F) at which point the reaction exothermed to a reaction temperature of 60°-66°C (140°-150°F). The reaction was conducted for one hour and then sampled for determination of free sodium bisulfite. After the one hour reaction time, this analysis showed that the percent free sodium bisulfite was 0.2 percent. The reactor was cooled to 37.8°C (100°F) and the product removed as the reaction was judged to be complete.
[0017] 1310 g of the thus-formed intermediate then was added to a three liter-four necked flask along with 416 g of lauryldimethyl amine. The flask was heated to 66°C-71°C (150°-160°F) and maintained at this temperature while the contents in the flask were stirred. After six hours reaction time, the contents in the flask changed from a milky liquid to a clear liquid. The reaction was continued for a total of 18 hours at which point the reaction was judged to be essentially complete. Sodium hydroxide (18 g, 50% concentration) was added to the flask and the temperature increased to 82°C (180°F) to hydrolyze unreacted epichlorohydrin/bisulfite intermediate. After two hours reaction time, the flask again was sampled and analyzed for percent free in NaCI which proved to be 8.0 percent. The contents of the flask then were cooled to 37.8°C (100°F) and sufficient sulfuric acid (25% concentration) was added to adjust the pH to about 8-8.5. The final analysis of the lauryldimethyl hydroxy sulfobetaine is set forth below:
The lauryldimethyl hydroxy sulfobetaine was tested for solubility in aqueous potassium hydroxide solution. Concentrations of potassium hydroxide at 10%, 20%, 30%, 40%, and 50% solutions were formulated at percent solids content of lauryldimethyl hydroxy sulfobetaine of 1%, 3%, 5%, and 10%. The lauryldimethyl hydroxy sulfobetaine was judged to be soluble at all concentrations of sulfobetaine at all concentrations of potassium hydroxide. The lauryldimethyl hydroxy sulfobetaine then was subjected to Ross-Miles foam test at 1.0% by weight actives in 72°F distilled water. The following foam heights were measured: initial, 205 mm; and +5 minutes, 26 mm. In 150 ppm hard (Ca) water at 1% concentration, Ross-Miles foam heights were: initial, 200 mm; and +5 minutes, 29 mm. Thus, it will be seen that the lauryldimethyl hydroxy sulfobetaine is low foaming as well as soluble in high concentrations of potassium hydroxide.
[0018] Next, the stability of the lauryldimethyl sulfobetaine to alkaline solutions was evaluated. Initial samples of the lauryldimethyl hydroxy sulfobetaine at 1%, 3%, and 5% by weight of a 50% solids solution of the sulfobetaine was established for 40% sodium hydroxide solutions. Surface tension and interfacial tension (against refined mineral oil, Nujol oil) were recorded initially, after one month storage in polyethylene bottles, and after 6 months of storage in polyethylene bottles. Samples for the tension evaluation were prepared by diluting the concentrate to 3% sodium hydroxide in deionized water for taking the measurements. The following results were recorded:
[0019] The above-tabulated results clearly demonstrate that the lauryldimethyl hydroxy sulfobetaine remains virtually unaffected when stored for time periods of up to six months in concentrated sodium hydroxide solutions. Thus, the lauryldimethyl hydroxy sulfobetaine has been demonstrated to be soluble in concentrated alkaline solutions, storage stable in concentrated alkaline solutions, and low foaming.
EXAMPLE 2
[0020] An octyl dimethyl hydroxy sulfobetaine was made in a manner like that described in Example 1. At 5% by weight sulfobetaine, Ross-Miles foam heights in deionized water were: initial, 47 mm; and +5 minutes, 40 mm. In 150 ppm (Ca) hard water, Ross-Miles foam heights were: initial, 43 mm; and +5 minutes, 36 mm. The low foaming properties of this betaine is demonstrated.
[0021] Samples of the octyl dimethyt hydroxy sulfobetaine were compounded at 1%, 0.1%, 0.025%, and 0.01% solids in DI Water for tension measurements. The following results were recorded.
1. An aqueous basic solution of a base, water, and a betaine having the following
general structure:
characterized in being improved for storage stability at a calculated pH of greater than 13 and in that R1 is a C8-C12 alkyl group; R2 and Ra are a methyl group, a 2-hydroxy ethyl group, or a 2-hydroxy propyl group; and R4 is H or OH; and said base is present in an amount to achieve a calculated pH of greater than 13.
characterized in being improved for storage stability at a calculated pH of greater than 13 and in that R1 is a C8-C12 alkyl group; R2 and Ra are a methyl group, a 2-hydroxy ethyl group, or a 2-hydroxy propyl group; and R4 is H or OH; and said base is present in an amount to achieve a calculated pH of greater than 13.
2. The basic solution of claim 1 characterized in that said base is selected from
the group consisting of sodium hydroxide, potassium hydroxide, sodium metasilicate,
tetrapotassium pyrophosphate, sodium tripolyphosphate, trisodium phospate, potassium
silicate, and mixtures thereof.
3. The basic solution of claim 2 characterized in that said base is selected from
potassium hydroxide, sodium hydroxide, or mixtures thereof.
4. The basic solution of claim 1 characterized in that said base is at a concentration
of greater than 30% by weight.
5. The basic solution of claim 1 characterized in that Ri is a C6-C10 alkyl group.
6. The basic solution of claim 1 characterized in that R1 is a Cε alkyl group.
7. The basic solution of claim 1 characterized in that said sulfobetaine ranges in
concentration from between about 0.05% and 10% by weight.
8. The basic solution of claim 4 characterized in that said base ranges in concentration
from between about 30% and 50% by weight.
9. The basic solution of claim 1 characterized in that Ri and R2 are Me.
10. The basic solution of claim 9 characterized in that R4 is OH.
11. A method for making a storage stable aqueous basic solution characterized in having
a calculated pH of greater than 13 of a sulfobetaine of the following general structure:
where R1 is a Cs-C12 alkyl group,
where R1 is a Cs-C12 alkyl group,
R2 and R3 are CHs, 2-hydroxy ethyl or 2-hydroxy propyl, comprising
(a) forming an aqueous epichlorohydrin/bisulfite intermediate;
(b) reacting said intermediate and a C6-C12 alkyl, R2, R3 amine in an aqueous reaction mixture; and
(c) adding a base to the thus-formed aqueous solution of said sulfobetaine if not already present therein to achieve said calculated pH of greater than 13.
12. The method of claim 11 characterized in that R1 is a C6-C10 alkyl group.
13. The method of claim 11 characterized in that R1 is a Cs alkyl group.
14. The method of claim 11 characterized in that said base is selected from the group
consisting of sodium hydroxide, potassium hydroxide, sodium metasilicate, tetrapotassium
pyrophosphate, sodium tripolyphosphate, trisodium phosphate, potassium silicate, and
mixtures thereof.
15. The method of claim 14 characterized in that said base is selected from potassium
hydroxide, sodium hydroxide, or mixtures thereof.
16. The method of claim 11 characterized in that the proportion of said sulfobetaine
and said aqueous basic solution ranges from between about 0.05 and 10 percent by weight.
17. The method of claim 11 characterized in that said intermediate is formed at a
reaction temperature of between 49°C and 93°C (120° and 200°F).
18. The method of claim 11 characterized in that said amine/intermediate reaction
is conducted at a temperature of between 37.8°C and 93°C (100° and 200°F).
19. The method of claim 11 characterized in that sufficient base is added to result
in at least 30% base concentration by weight.
20. The method of claim 19 characterized in that said base concentration is between
about 30% and 50% by weight.
1. Wäßrige basische Lösung einer Base, Wasser und eines Betains der allgemeinen Formel
gekennzeichnet durch eine verbesserte Lagerfähigkeit bei einem berechneten pH-Wert von größer als 13 und dadurch, daß R1 eine C6-C12-Alkylgruppe ist, R2 und Rs sind Methylgruppen, eine 2-Hydroxyethylgruppe oder eine 2-Hydroxypropylgruppe und R4 ist H oder OH, wobei die Base in einer Menge zum Erreichen eines berechneten pH-Wertes von größer als 13 vorliegt.
gekennzeichnet durch eine verbesserte Lagerfähigkeit bei einem berechneten pH-Wert von größer als 13 und dadurch, daß R1 eine C6-C12-Alkylgruppe ist, R2 und Rs sind Methylgruppen, eine 2-Hydroxyethylgruppe oder eine 2-Hydroxypropylgruppe und R4 ist H oder OH, wobei die Base in einer Menge zum Erreichen eines berechneten pH-Wertes von größer als 13 vorliegt.
2. Basische Lösung nach Anspruch 1, dadurch gekennzeichnet, daß die Base aus der aus
Natriumhydroxid, Kaliumhydroxid, Natriummetasilicat, Tetrakaliumpyrophosphat, Natriumtripolyphosphat,
Trinatriumphosphat, Kaliumsilicat und Mischungen davon bestehenden Gruppen ausgewählt
ist.
3. Basische Lösung nach Anspruch 2, dadurch gekennzeichnet, daß die Base aus Kaliumhydroxid,
Natriumhydroxid oder Mischungen davon ausgewählt ist.
4. Basische Lösung nach Anspruch 1, dadurch gekennzeichnet, daß die Base in einer
Konzentration von größer als 30 Gew.-% vorliegt.
5. Basische Lösung nach Anspruch 1, dadurch gekennzeichnet, daß R1 eine Cs-Clo-Alkylgruppe ist.
6. Basische Lösung nach Anspruch 1, dadurch gekennzeichnet, daß R1 eine Ca-Alkylgruppe ist.
7. Basische Lösung nach Anspruch 1, dadurch gekennzeichnet, daß die Konzentration
des Sulfobetains in einem Bereich zwischen etwa 0,05 und 10 Gew.-% liegt.
8. Basische Lösung nach Anspruch 1, dadurch gekennzeichnet, daß die Konzentration
der Base in einem Bereich zwischen etwa 30 und 50 Gew.-% liegt.
9. Basische Lösung nach Anspruch 1, dadurch gekennzeichnet, daß R1 und R2 Me sind.
10. Basische Lösung nach Anspruch 1, dadurch gekennzeichnet, daß R4 OH ist.
11. Verfahren zur Herstellung einer wäßrigen basischen Lösung, gekennzeichnet durch
einen berechneten pH-Wert von größer als 13 und ein Sulfobetain der allgemeinen Formel
worin R1 eine C6-C12-Alkylgruppe ist, R2 und R3 CH3, 2-Hydroxyethyl oder 2-Hydroxypropyl sind, umfassend
worin R1 eine C6-C12-Alkylgruppe ist, R2 und R3 CH3, 2-Hydroxyethyl oder 2-Hydroxypropyl sind, umfassend
(a) die Bildung eines wäßrigen Epichlorhydrin/Bisulfitzwischenprodukts,
(b) die Umsetzung des Zwischenprodukts und eines Cs-C12-Alkyl-, R2-, Rs- Amins in einer wäßrigen Reaktionsmischung und
(c) das Hinzufügen einer Base zu der so gebildeten wäßrigen Lösung des Sulfobetains, falls darin noch nicht enthalten, zum Erreichen des berechneten pH-Wertes von größer als 13.
12. Verfahren nach Anspruch 11, dadurch gekennzeichnet, daß Ri eine C6-C10-Alkylgruppe ist.
13. Verfahren nach Anspruch 11, dadurch gekennzeichnet, daß R1 eine Cs-Alkylgruppe ist.
14. Verfahren nach Anspruch 11, dadurch gekennzeichnet, daß die Base aus der aus Natriumhydroxid,
Kaliumhydroxid, Natriummetasilicat, Tetrakaliumpyrophosphat, Natriumtripolyphosphat,
Trinatriumphosphat, Kaliumsilicat und Mischungen davon bestehenden Gruppe ausgewählt
ist.
15. Verfahren nach Anspruch 14, dadurch gekennzeichnet, daß die Base aus Kaliumhydroxid,
Natriumhydroxid oder Mischungen davon ausgewählt ist.
16. Verfahren nach Anspruch 11, dadurch gekennzeichnet, daß der Anteil des Sulfobetains
und der wäßrigen basischen Lösung in einem Bereich zwischen etwa 0.05 und 10 Gew.-%
liegt.
17. Verfahren nach Anspruch 11, dadurch gekennzeichnet, daß das Zwischenprodukt bei
einer Reaktionstemperatur zwischen 49°C und 93° (120° und 200°F) gebildet wird.
18. Verfahren nach Anspruch 11, dadurch gekennzeichnet, daß die Amin/Zwischenproduktreaktion
bei einer Temperatur von zwischen 37,8°C und 93°C (100° und 200°F) durchgeführt wird.
19. Verfahren nach Anspruch 11, dadurch gekennzeichnet, daß ausreichend Base hinzugefügt
wird, um eine Basenkonzentration von wenigstens 30 Gew.-% zu erzielen.
20. Verfahren nach Anspruch 19, dadurch gekennzeichnet, daß die Konzentration der
Base in einem Bereich zwischen etwa 30 und 50 Gew.-% liegt.
1. Solution basique aqueuse d'une base, d'eau et d'une bétaïne répondant à la structure
générale suivante:
caractérisée en ce qu'elle est améliorée pour la stabilité à la conservation à un pH calculé supérieur à 13 et en ce que R1 représente un groupe alkyle en C6-C12; R2 et R3 représente chacun un groupe méthyle, un groupe 2-hydroxyéthyle ou un groupe 2-hydroxy-propyle; et R4 représente H ou OH, tandis que cette base est présente en une quantité permettant d'obtenir un pH calculé supérieur à 13.
caractérisée en ce qu'elle est améliorée pour la stabilité à la conservation à un pH calculé supérieur à 13 et en ce que R1 représente un groupe alkyle en C6-C12; R2 et R3 représente chacun un groupe méthyle, un groupe 2-hydroxyéthyle ou un groupe 2-hydroxy-propyle; et R4 représente H ou OH, tandis que cette base est présente en une quantité permettant d'obtenir un pH calculé supérieur à 13.
2. Solution basique selon la revendication 1, caractérisée en ce que cette base est
choisie parmi le groupe comprenant l'hydroxyde de sodium, l'hydroxyde de potassium,
le métasilicate de sodium, le pyrophosphate tétrapotassique, le tripolyphosphate de
sodium, le phosphate trisodique, le silicate de potassium et leurs mélanges.
3. Solution basique selon la revendication 2, caractérisée en ce que cette base est
choisie parmi l'hydroxyde de potassium, l'hydroxyde de sodium ou leurs mélanges.
4. Solution basique selon la revendication 1, caractérisée en ce que cette base est
présente en une concentration supérieure à 30% en poids.
5. Solution basique selon la revendication 1, caractérisée en ce que R1 est un groupe alkyle en C6-C10.
6. Solution basique selon la revendication 1, caractérisée en ce que R1 est un groupe alkyle en C8.
7. Solution basique selon la revendication 1, caractérisée en ce que la concentration
de cette sulfobétaïne se situe entre environ 0,05 et 10% en poids.
8. Solution basique selon la revendication 4, caractérisée en ce que la concentration
de cette base se situe entre environ 30 et 50% en poids.
9. Solution basique selon la revendication 1, caractérisée en ce que R1 et R2 représentent chacun Me.
10. Solution basique selon la revendication 9, caractérisée en ce que R4 représente
OH.
11. Procédé de préparation d'une solution basique aqueuse stable à la conservation,
caractérisé en ce que la solution a un pH calculé de plus de 13 d'une sulfobétaïne
répondant à la structure générale suivante:
où R1 représente un groupe alkyle en C6-C12, R2 et R3 représentent chacun CH3, un groupe 2-hydroxyéthyle ou un groupe 2-hydroxy-propyle, caractérisé en ce qu'il comprend les étapes qui consistent à:
où R1 représente un groupe alkyle en C6-C12, R2 et R3 représentent chacun CH3, un groupe 2-hydroxyéthyle ou un groupe 2-hydroxy-propyle, caractérisé en ce qu'il comprend les étapes qui consistent à:
(a) former un produit intermédiaire aqueux d'épichlorhydrine/bisulfite;
(b) faire réagir ce produit intermédiaire et une alkyle(en C6-C12)amine R2, R3 dans un mélange réactionnel aqueux; et
(c) ajouter une base à la solution aqueuse ainsi formée de cette sulfobétaine si tant est qu'elle n'y est déjà pas présente, pour obtenir le pH calculé supérieur à 13.
12. Procédé selon la revendication 11, caractérisé en ce que R1 représente un groupe alkyle en Cs-Cio.
13. Procédé selon la revendication 11, caractérisé en ce que R1 représente un groupe alkyle en Ca.
14. Procédé selon la revendication 11, caractérisé en ce que cette base est choisie
parmi le groupe comprenant l'hydroxyde de sodium, l'hydroxyde de potassium, le métasilicate
de sodium, le pyrophosphate tétrapotassique, le tripolyphosphate de sodium, le phosphate
trisodique, le silicate de potassium et leurs mélanges.
15. Procédé selon la revendication 14, caractérisé en ce que cette base est choisie
parmi l'hydroxyde de potassium, l'hydroxyde de sodium ou leurs mélanges.
16. Procédé selon la revendication 11, caractérisé en ce que la proportion de la sulfobétaïne
et de la solution basique aqueuse se situe entre environ 0,05 et 10% en poids.
17. Procédé selon la revendication 11, caractérisé en ce que le produit intermédiaire
est formé à une température réactionnelle se situant entre 49 et 93°C (120 et 200°F).
18. Procédé selon la revendication 11, caractérisé en ce que la réaction amine/produit
intermédiaire est effectuée à une température se situant entre 37,8°C et 93°C (100 et 200°F).
19. Procédé selon la revendication 11, caractérisé en ce que la base suffisante est
ajoutée pour obtenir au moins une concentration de 30% en poids de la base.
20. Procédé selon la revendication 19, caractérisé en ce que la concentration de la
base se situe entre environ 30 et 50% en poids.