WO1993002171A1

WO1993002171A1 - Method of stabilizing aqueous suspensions of zeolites

Info

Publication number: WO1993002171A1
Application number: PCT/EP1992/001590
Authority: WO
Inventors: Karl-Heinz Schmid; Andreas Syldath; Ditmar Kischkel
Original assignee: Henkel Kommanditgesellschaft Auf Aktien
Priority date: 1991-07-22
Filing date: 1992-07-13
Publication date: 1993-02-04
Also published as: EP0595919B1; DK0595919T3; EP0595919A1; ATE141640T1; DE4124247A1; JPH07502963A; DE59206964D1; ES2090669T3

Abstract

The method proposed enables aqueous zeolite suspensions to be stabilized by adding to the suspension at least one non-ionic surfactant selected from the group consisting: a) guerbet-alcohol/poly(ethyleneglycol) ethers of the formula (I): R10-(CH2CH20)mH in which R1 is a branched-chain alkyl group with 16 to 20 carbon atoms and m is a number from 3 to 15; b) fatty-alcohol/poly(ethyleneglycol) ethers of the formula (II): R20-(CH2CH20)nH in which R2 is an aliphatic hydrocarbon group with 12 to 22 carbon atoms and 1, 2 or 3 double bonds and n is a number from 1 to 10; c) fatty-alcohol/polyglycol ethers of the formula (III) in which R3 is an alkyl group with 6 to 10 carbon atoms, p is a number from 1 to 5 and q is a number from 3 to 15; d) alkyl and/or alkenyl glycosides of the formula (IV): R40-(G)x in which R4 is an alkyl and/or alkenyl group with 6 to 22 carbon atoms, G is a glycose unit derived from a sugar with 5 or 6 carbon atoms and x is a number between 1 and 10.

Description

Process for the stabilization of aqueous

Zeolite suspensions

Field of the Invention

The invention relates to a method for stabilizing aqueous zeolite suspensions by adding selected nonionic surfactants.

State of the art

Zeolites, in particular of the zeolite A type, are of particular importance as builders of modern detergents and have largely replaced the polyphosphates that have been used for decades. Their advantages lie not only in their high calcium binding capacity, but also in their high ecotoxicological compatibility [Tens.Surf. Det., 24, 322 (1987)].

During production, the zeolites are obtained in the form of aqueous suspensions, which can either be stored as such and placed on the market, or can be subjected to spray drying. Zeolites have an extremely low solubility in water, so that suspensions of these substances are easy sediment. In the most favorable case, this leads to a phase separation, but usually considerable amounts of the solid separate out on the bottom of the vessels during storage, harden and then have to be separated, comminuted and resuspended with great technical effort. In other cases, the viscosity of the suspension increases so much that decanting or pumping over becomes difficult, if not impossible, and in any case involves considerable product losses.

There has been no shortage of attempts in the past to stabilize aqueous zeolite suspensions in such a way that they are stable in storage for a sufficient time and can be transported through pipelines without clogging them.

For example, German patent application DE 33 30 220 AI proposes adding 0.5 to 5% by weight of a mixture of fatty alcohol ethoxylates and fatty alcohol sulfates or fatty alcohol ether sulfates to the suspensions.

German patent application DE 34 08 040 A1 describes a process for stabilizing 65% by weight zeolite A suspensions with the aid of 0.01 to 0.25% by weight xanthan gum and carboxyl- or hydroxyl-containing polymers.

According to the teaching of German patent application DE 34 23 351 AI, zeolite suspensions can also be stabilized at pH 9 to 10 by adding polyglycol ethers, fatty alcohol ether sulfates, fatty acid alkanolamides or fatty acid monoglycerides. The literature also describes the use of numerous other stabilizers, for example polycarboxylates with molecular weights above 1500, phosphonic acids, phosphoric acid esters, alkylbenzenesulfonates, layered silicates [DE-OS 27 388], alkylphenol polyglycol ethers [DE 34 01 861 AI], isotridecyl polyglycol ethers [DE 34 44 311 AI] and addition products of ethylene oxide onto oxo alcohols [DE 37 19 042 AI] are known.

The methods of the prior art, however, have disadvantages with regard to sufficient stabilization over a larger temperature range, the amounts required and the viscosity and the residue-free run-out behavior of the suspensions.

The object of the invention was therefore to develop an improved method for stabilizing aqueous zeolite suspensions which is free from the disadvantages described.

Description of the invention

The invention relates to a process for stabilizing aqueous zeolite suspensions by adding surfactants, which is characterized in that the suspensions are selected from at least one nonionic surfactant from the group consisting of a) Guerbet alcohol polyethylene glycol ethers of the formula (I), R- ¹ -O - (CH ₂ CH ₂ O) _m H (l) in which R ^{1 is} a branched alkyl radical having 16 to 20 carbon atoms and m is a number from 3 to 15, b) fatty alcohol polyethylene glycol ethers of the formula (II),

R ² O- (CH ₂ CH ₂ O) _n H (II) in which R ^{2 represents} an aliphatic hydrocarbon radical having 12 to 22 carbon atoms and 1, 2 or 3 double bonds and n represents numbers from 1 to 10, c) fatty alcohol polyglycol ethers Formula (III),

CH ₃

|

R ³ O- (CH ₂ CHO) _p (CH ₂ CH ₂ O) _q H (III) in R ³ for an alkyl radical with 6 to 10 carbon atoms, p for numbers from 1 to 5 and q for numbers of 3 to 15, and d) alkyl and / or alkenyl glycosides of the formula (IV),

R ⁴ O- (G) _x (IV) in R ⁴ for an alkyl and / or alkenyl radical with 6 to 22 carbon atoms, G for a glycose unit derived from a sugar with 5 or 6 carbon atoms, and x stands for a number between 1 and 10, is added. Surprisingly, it was found that the use of the selected nonionic surfactants or their mixtures with one another can reliably stabilize suspensions of zeolites over a wide temperature range, in particular from 10 to 60 ° C. The suspensions have a high storage stability even over a longer period of time, can be conveyed through pipelines and can be easily poured out with only minor product losses.

Zeolites are optionally to be understood as meaning water-containing alkali or alkaline earth aluminosilicates of the general formula (V)

M ₂ / _z O * Al ₂ O ₃ * x SiO ₂ * y H ₂ O (V) in the M for an alkali or alkaline earth metal of valence z, x for numbers from 1.8 to 12 and y for numbers from 0 to 8 is [Chem.iuZt., 20, 117 (1986)].

Typical examples of zeolites, the aqueous dispersions of which can be stabilized in the process according to the invention, are the naturally occurring minerals clinoptilolite, erionite or chabasite. However, synthetic zeolites are preferred, for example

Zeolite X Na ₈₆ [(AlO ₂ ) 86 (SiO ₂ ) 106] * 264 H ₂ O

Zeolite Y Na ₅₆ [(AlO ₂ ) 56 (SiO ₂ ) 136] * 325 H ₂ O

Zeolite LK ₉ [(AlO ₂ ) 9 (SiO ₂ ) 27] * 22 H ₂ O

Mordenite Na _8.7 [(A10 ₂ ) _8.7 (SiO ₂ ) 39.3- * 24 H ₂ O and in particular Zeolite A Na ₁₂ [(AlO ₂ ) l2 (siO ₂ ) 12] * 27 H ₂ O.

The aqueous suspensions can contain the zeolites in amounts of 20 to 60, preferably 25 to 50% by weight.

Addition products of ethylene oxide and / or propylene oxide with Guerbet or fatty alcohols are known nonionic surfactants which are produced on an industrial scale by the known process of alkoxylation.

Guerbet alcohol polyethylene glycol ethers (group a) which can be used for the purposes of the process according to the invention are addition products of an average of 3 to 15 mol of ethylene oxide to 1 mol of a branched primary alcohol of the Guerbet type; regarding structure and production of Guerbet alcohols, see Soap, Cosm.Chem. Spec, 52 (1987). Typical examples of Guerbet alcohol polyethylene glycol ethers which can be used according to the invention are addition products of 3 to 15 mol of ethylene oxide with 2-hexyldecanol or 2-octyldodecanol. Compounds of the formula (I) in which R ^{1 is} a branched alkyl radical having 16 or 20 carbon atoms and m is a number from 3 to 10 are preferred.

As fatty alcohol polyethylene glycol ethers, which form group b), adducts of an average of 1 to 10 moles of ethylene oxide with technical fatty alcohols with 12 to 22 carbon atoms and 1, 2 or 3 double bonds are suitable. Typical examples are ethylene oxide adducts with palmitoleyl alcohol, oleyl alcohol, elaidyl alcohol, petroselinyl alcohol, linolyl alcohol, linolenyl alcohol, gadoleyl alcohol or erucyl alcohol. Preferred are fatty alcohol polyglycol ethers of the formula (II) in which R ^{2 is} an alkenyl radical having 12 to 18 carbon atoms and n is a number from 4 to 9, in particular 4 to 5. The fatty alcohol polyethylene glycol ethers can have both a conventional and a narrow homolog distribution.

In addition, fatty alcohol polyethylene glycol ethers can also be used, which are not derived from pure alcohols but from technical cuts, such as those obtained in the selective hydrogenation of fatty acid methyl ester fractions based on vegetable or animal raw materials. The technical cuts can also contain saturated fatty alcohols of the C number range mentioned, provided that the iodine number of the fatty alcohol fraction used is at least 10. Fatty alcohol polyethylene glycol ethers based on fatty alcohols which have an iodine number of 10 to 125, in particular 55 to 110, are preferably used. Examples of these are fatty alcohol polyglycol ethers based on peanut oil, cottonseed oil, coriander oil, soybean oil, beef tallow, rapeseed oil (oleic acid content> 80% by weight), sunflower oil (oleic acid content> 80% by weight) and in particular coconut oil. An adduct of 6 to 8 mol of ethylene oxide with a technical oleyl alcohol based on coconut alcohol with an iodine number of 10 to 20 is particularly preferred.

Fatty alcohol polyglycol ethers (group c) are addition products of on average 1 to 5 moles of propylene oxide and 3 to 15 moles of ethylene oxide with fatty alcohols having 8 to 10 carbon atoms. The addition of propylene oxide and ethylene oxide can take place statistically (Random distribution). However, the preferred procedure for the preparation of the products is that the fatty alcohols are first reacted with propylene oxide in the presence of typical alkoxylation catalysts, for example sodium methylate or hydrotalcite, the propoxylate is freed from low-boiling impurities, if appropriate by distillation, and then reacted with ethylene oxide (block distribution ). Preference is given to using fatty alcohol polyglycol ethers of the formula (III) in which R3 is an octyl radical, p is 1 and q is a number from 1 to 10.

The alkyl and / or alkenyl glycosides (group d) to be used according to the invention are also known substances. Processes for their preparation are based, for example, on glucose or starch which are reacted with alcohols either directly or via the intermediate stage of the butyl glycosides [US 3,547,828, US 3,839,318 , DE-A-37 23 826].

The alkyl radical R ⁴ in formula (IV) can be derived from primary saturated or monounsaturated alcohols having 6 to 22, preferably 12 to 18, carbon atoms. Typical examples are capronic alcohol, caprylic alcohol, capric alcohol, lauryl alcohol, myristyl alcohol, cetyl alcohol, palmitoleyl alcohol, stearyl alcohol, elaidyl alcohol, oleyl alcohol, petroselinyl alcohol, behenyl alcohol or erucyl alcohol and their technical mixtures.

Alkyl or alkenyl glycosides of the formula (IV) which are particularly suitable for the stabilization of aqueous zeolite suspensions can be derived from aldoses or ketoses. Because of the higher reactivity and the technical availability, primarily the glycosides of the reducing saccharides and especially glucose come into consideration. The preferred alkyl and / or alkenyl glycosides are therefore the alkyl and / or alkenyl glucosides.

The index x in formula (IV) indicates the degree of oligomerization, i.e. H. the distribution of mono- and oligoglycosides is present and stands for a number between 1 and 10. While x must always be an integer in a given compound and here can assume the values x = 1 to 6, the value x is for a certain alkyl - or alkenyl glycoside is an analytically calculated value that usually represents a fractional number. Alkyl and / or alkenyl glycosides with an average degree of oligomerization x of 1 to 3 are preferably used. Those alkyl and / or alkenyl glycosides whose degree of oligomerization x is less than 1.5 and in particular between 1.1 and 1.4 are particularly preferred.

Particularly stable zeolite suspensions are obtained if the stabilizers used are alkyl glycosides of the formula (IV) in which R ^{4 is} a linear alkyl radical having 12 to 18 carbon atoms, G is a glucose unit and x is a number from 1 to 3 .

The stabilizers of groups a) to d) can be used individually or in mixtures. It is also possible to combine several stabilizers within groups a) to d). Mixtures of addition products with an average of 7 and 9 moles of ethylene oxide on technical have proven particularly effective Oleyl alcohol in a weight ratio of 20:80 to 80:20 has been proven. In a further preferred embodiment of the invention, a mixture comprising i) 10 to 25% by weight of a fatty alcohol polyethylene glycol ether of the formula (11) _/ in which R2 is an alkenyl radical having 12 to 18 carbon atoms and n is a number from 5 to 10, and ii) 75 to 90% by weight of an alkyl glycoside of the formula (IV) in which R ^{4 is} an alkyl radical having 12 to 18 carbon atoms, G is a glucose unit and x is a number from 1.1 to 1.4 . Mixtures of this type are obtained, for example, as an intermediate in the production of alkyl glucosides and can be used without further purification to stabilize aqueous zeolite suspensions [DE 36 03 581 AI].

The introduction of the stabilizers into the suspension is not critical and can, for. B. mechanically by stirring, optionally at elevated temperatures of 50 ° C. There is no chemical reaction. The nonionic surfactants can be added to the suspensions in amounts of 0.1 to 5, preferably 1 to 3% by weight, based on the suspension.

The following examples are intended to explain the subject matter of the invention in more detail without restricting it. Examples

An aqueous suspension of zeolite A (Sasil ^(R) , solids content: 49.6% by weight, content of free alkali: 0.32% by weight, from Henkel KGaA) was placed in a 500 ml glass beaker and each with 1.5% by weight - based on the suspension - of the stabilizers or stabilizer mixtures - calculated as solids - added.

Stabilizers used - examples according to the invention:

(30% by weight aqueous pastes):

A adduct of an average of 1 mole of propylene oxide and 3 moles of ethylene oxide with octanol

B Addition product of an average of 7.2 moles of ethylene oxide with a technical oleyl alcohol based on rapeseed oil (iodine number = 108)

C Addition product of an average of 9 moles of ethylene oxide with a technical oleyl alcohol based on rapeseed oil (iodine number = 108)

D Addition product of an average of 3 moles of ethylene oxide with a C ₁₆ Guerbet alcohol

EC _12/14 alkyl glucoside based on hardened coconut alcohol;

Degree of oligomerization x = 1.3 Stabilizers used - comparative examples:

(30% by weight aqueous pastes):

G Addition product of an average of 5 moles of ethylene oxide with isotridecyl alcohol

H Addition product of an average of 7 moles of ethylene oxide with isotridecyl alcohol

I adduct of an average of 9 moles of ethylene oxide with isotridecyl alcohol

J _Addition product of an average of 7 moles of ethylene oxide with technical C _12/18 coconut _fatty alcohol (iodine number <0.3)

The stability of the suspensions was assessed over a period of 1 to 6 days according to the following criteria:

1) Sedimentation (Sd):

The height of the liquid phase above the suspension was determined in mm.

2) sediment (Bs):

1 = low sediment, no hardening

2 = low sediment, slight hardening

3 = low sediment, severe hardening

4 = strong sediment, no hardening

5 = strong sediment, slight hardening

6 = strong sediment, severe hardening

3) Viscosity (Vis):

I = thin to VI = pasty, tough

4) outlet (A):

Residue in the beaker after decanting; Specification in% by weight based on the suspension.

The results are summarized in Tab. 1 and Tab. 2. Examples 1 to 11 are according to the invention, Examples VI to V4 are used for comparison. All percentages as% by weight.

Legend: S = stabilizer (non-ionic surfactant)

Ratio = weight ratio of the used

Stabilizers

cS = concentration of the stabilizers used

Claims

1. A process for stabilizing aqueous zeolite suspensions by adding surfactants, characterized in that the suspensions are selected from at least one nonionic surfactant from the group consisting of a) Guerbet alcohol polyethylene glycol ethers of the formula (I),

R ¹ O- (CH ₂ CH ₂ O) _m H (I) in which R ^{1 represents} a branched alkyl radical having 16 to 20 carbon atoms and m represents numbers from 3 to 15, b) fatty alcohol polyethylene glycol ethers of the formula (II),

CH ₃

R ³ O- (CH ₂ CHO) _p (CH ₂ CH ₂ O) _q H (III) in which R ^{3 is} an alkyl radical having 6 to 10 carbon atoms, p is a number from 1 to 5 and q is a number from 3 to 15, and d) alkyl and / or alkenyl glycosides of the formula (IV),

R ⁴ O- (G) _x (IV) in R ⁴ for an alkyl and / or alkenyl radical with 6 to 22 carbon atoms, G for a glycose unit derived from a sugar with 5 or 6 carbon atoms, and x stands for a number between 1 and 10, is added.

2. The method according to claim 1, characterized in that the nonionic surfactants are added to aqueous suspensions of zeolite A, which have solids contents of 20 to 60 wt .-%.

3. Process according to claims 1 and 2, characterized in that Guerbet alcohol polyethylene glycol ether of the formula (I) is used in which R ^{1 is} a branched alkyl radical having 16 or 20 carbon atoms and m is a number from 3 to 10.

4. The method according to at least one of claims 1 to 3, characterized in that fatty alcohol polyglycol ethers of the formula (II) are used in which R ^{2 is} an alkenyl radical having 16 to 18 carbon atoms and n is a number from 4 to 9.

5. The method according to at least one of claims 1 to 4, characterized in that fatty alcohol polyglycol ether of the formula (III) is used in which R ^{3 is} an octyl radical, p is 1 and q is a number from 1 to 10.

6. The method according to at least one of claims 1 to 5, characterized in that alkyl glycosides of the formula (IV) are used, in which R ⁴ for a linear alkyl radical having 12 to 18 carbon atoms, G for a glucose unit and x for numbers of 1 to 3 stands.

7. The method according to at least one of claims 1 to 6, characterized in that a mixture of i) 10 to 25 wt .-% of a fatty alcohol polyethylene glycol of the formula (II) in which R2 for an alkenyl radical having 12 to 18 carbon atoms and n represents numbers from 5 to 10, and ii) 75 to 90% by weight of an alkyl glycoside of the formula (IV) in which R ^{4 is} an alkyl radical having 12 to 18 carbon atoms, G is a glucose unit and x is Numbers from 1.1 to 1.4,

-% by weight based on the mixture - used.

8. The method according to at least one of claims 1 to 7, characterized in that the suspensions, the nonionic surfactants in amounts of 0.1 to 5 wt .-% - based on the suspension - is added.