DE4124247A1 - METHOD FOR STABILIZING AQUEOUS ZEOLITE SUSPENSIONS - Google Patents

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): R<1>0-(CH2CH20)mH in which R<1> 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): R<2>0-(CH2CH20)nH in which R<2> 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 R<3> 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): R<4>0-(G)x in which R<4> 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

Field of the Invention

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

State of the art

Zeolites, in particular of the zeolite A type, have a be of particular importance as the building blocks of modern detergents and have the polyphos used for decades phate largely replaced. Your advantages are not there only in a high calcium binding capacity, but in particular also in their high ecotoxicological compatibility (Tens. Surf. Det., 24, 322 (1987)).

The zeolites become more aqueous in the production Suspensions received, either stored as such and marketed or spray dried under can be thrown. Zeolites are extremely small Solubility in water, making suspensions of these substances easy  sediment. In the best case, this leads to a Pha separation, but usually differ during storage significant amounts of the solid on the bottom of the vessels, harden and then have to do with great technical Effort separated, crushed and suspended again will. In other cases, the viscosity of the suspensions increases sion so strongly that it is difficult to transfer or transfer, if not impossible at all and in any case with considerable product losses.

There has been no shortage of attempts in the past stabilize aqueous zeolite suspensions so that they are stable in storage for a sufficient time and by tube lines can be transported without ver Plug.

For example, in the German patent application DE 33 30 220 A1 suggested the suspensions 0.5 to 5 wt .-% a mixture of fatty alcohol ethoxylates and fatty alcohol add sulfates or fatty alcohol ether sulfates.

In the German patent application DB 34 08 040 A1 a Process for stabilizing 65% by weight zeolite A- Suspensions with the aid of 0.01 to 0.25% by weight of xanthan gum as well as carboxyl- or hydroxyl-containing polymers.

According to the teaching of German patent application DE 34 23 351 A1 zeolite suspensions can also be added by adding polygly colethers, fatty alcohol ether sulfates, fatty acid alkanolamides or fatty acid monoglycerides stabilized at pH 9-10 will.  

Furthermore, the use of numerous is from the literature other stabilizers, for example polycarboxylates Molecular weights above 1500, phosphonic acids, phosphoric acid reesters, alkylbenzenesulfonates, layered silicates (DE-OS 27 388), Alkylphenol polyglycol ethers (DE 34 01 861 A1), Isotri decyl polyglycol ethers (DE 34 44 311 A1) and addition pro Products of ethylene oxide with oxo alcohols (DE 37 19 042 A1) be knows.

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

The object of the invention was therefore a verbes Process for the stabilization of aqueous zeolite Develop suspensions that are free from those described Disadvantages is.

Description of the invention

The invention relates to a method for stabilization aqueous zeolite suspensions by adding surfactants, the is characterized in that the suspensions at least a nonionic surfactant selected from the group 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 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 the R ² for an aliphatic hydrocarbon radical having 12 to 22 carbon atoms and 1, 2 or 3 double bonds and n for numbers stands from 1 to 10,
• c) fatty alcohol polyglycol ethers of the formula (III), in which R ^{3 represents} an alkyl radical having 6 to 10 carbon atoms, p represents numbers from 1 to 5 and q represents numbers from 3 to 15, and
• d) alkyl and / or alkenyl glycosides of the formula (IV), R ⁴ O- (G) _x (IV) in which R ^{4 is} an alkyl and / or alkenyl radical having 6 to 22 carbon atoms, G is a glycose unit, which is derived from a sugar with 5 or 6 carbon atoms, and x stands for a number between 1 and 10,

is formed, adds.  

Surprisingly, it was found that the use of the selected nonionic surfactants mentioned or their Mi suspension of zeolites over one another wide temperature range, in particular from 10 to 60 ° C. can stabilize reliably. The suspensions also show high storage stability over a longer period of time, can be conveyed through pipelines and can be Pour out easily with only minor product losses.

Water-containing alkali or alkaline earth aluminosilicates of the general formula (V) understand,

M _{2 / z} O · Al₂O₃ · x SiO₂ · y H₂O (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 stands [Chem. i. u. Zt., 20, 117 (1986)].

Typical examples of zeolites, their aqueous dispersions can be stabilized in the sense of the inventive method are the naturally occurring minerals Clinoptilolite, erionite or chabazite. However, are preferred synthetic zeolites, for example

Zeolite X Na₈₆ [(AlO₂) ₈₆ (SiO₂) ₁₀₆] · 264 H₂O
Zeolite Y Na₅₆ [(AlO₂) ₅₆ (SiO₂) ₁₃₆] · 325 H₂O
Zeolite L Kg [(AlO₂) ₉ (SiO₂) ₂₇ · 22 H₂O
Mordenite Na _8.7 [(AlO₂) _8.7 (SiO₂) _39.3 ] · 24 H₂O

and particularly

Zeolite A N₁₂ [(AlO₂) ₁₂ (SiO₂) ₁₂] · 27 H₂O.

The aqueous suspensions can the zeolites in amounts of Contain 20 to 60, preferably 25 to 50 wt .-%.

Addition products of ethylene oxide and / or propylene oxide Guerbet or fatty alcohols are known nonionic Surfactants, which on an industrial scale by itself known methods of alkoxylation can be produced.

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 Guerbet 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 adducts of 3 to 15 moles of ethylene oxide with 2-hexyldecanol or 2-octyldodecanol. Preferred compounds of the formula (I) are those in which R ^{1 is} a branched alkyl radical having 16 or 20 carbon atoms and m is a number from 3 to 10.

As fatty alcohol polyethylene glycol ethers, which form group b), addition products of an average of 1 to 10 moles of ethylene oxide onto technical fatty alcohols with 12 to 22 carbon atoms and 1, 2 or 3 double bonds come into consideration. Typical examples are ethylene oxide adducts with pal mitoleyl 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 represents} an alkenyl radical having 12 to 18 carbon atoms and n represents numbers from 7 to 9.

In addition, fatty alcohol polyethylene glycol ether be used that are not different from pure alcohols, but derive technical cuts, such as those wise in the selective hydrogenation of fatty acid methyl ester Fractions based on vegetable or animal raw substances are preserved. The technical cuts can be there also saturated fatty alcohols of the C number mentioned contain rich, provided the iodine number of the fat used alcohol fraction is at least 10. Preferably be Fatty alcohol polyethylene glycol ether based on fatty alcohols used which have an iodine number of 10 to 125, in particular 55 have up to 110. Examples of these are fatty alcohol poly glycol ether based on peanut oil, cottonseed oil, korian der oil, soybean oil, beef tallow, beet oil (oleic acid content <80% by weight), Sunflower oil (oleic acid content <80% by weight) and in particular Coconut oil.

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 to fatty alcohols with 8 to 10 carbon atoms. The addition of propylene oxide and ethylene oxide can take place statistically (random distribution). However, the preparation of the products is preferably carried out by first reacting the fatty alcohols with propylene oxide in the presence of typical alkoxylation catalysts, for example sodium methylate or hydrotalcite, optionally removing low-boiling impurities from the propoxylate and then reacting them with ethylene oxide (block distribution ). Preference is given to using fatty alcohol polyglycol ethers of the formula (III) in which R ^{3 represents} an octyl radical, p represents 1 and q represents numbers from 1 to 10.

The all and / or alkenyl to be used according to the invention Glycosides (group d) are also known substances. Processes for their manufacture go, for example Glucose or starch, either directly or through the Intermediate stage of the butyl glycosides implemented with alcohols (US 35 47 828, US 38 39 318, 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, petrolinyl alcohol, behenyl alcohol or erucyl alcohol and their technical mixtures.

Alkyl or alkenyl glycosides of the formula (IV), which are in special way for the stabilization of aqueous Zeo lith suspensions can be used from aldoses or Derive ketoses. Because of the higher reactivity and the technical availability primarily come from the glycosides reducing saccharides and especially glucose into consideration. The preferred alkyl and / or Alkenyl glycosides are therefore the alkyl and / or alkenyl glu coside.  

The index x in formula (IV) indicates the degree of oligomerization, d. H. the distribution of mono- and oligoglycosides on and stands for a number between 1 and 10. While x in a given connection must always be an integer and here everything can assume the values x = 1 to 6, is the value x for a certain alkyl or alkenyl glycoside an analytical determined calculated size, mostly a broken one Represents number. Alkyl and / or alkenyl are preferred glycosides with an average degree of oligomerization x of 1 used to 3. Such alkyl and / or or alkenyl glycosides, the degree of oligomerization of which is x smaller than 1.5 and is in particular between 1.1 and 1.4.

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

The stabilizers of groups a) to d) can be used individually or can be used in blends. It is also also possible, several groups within groups a) to d) to combine gates with each other. As particularly effective have, for example, mixtures of addition products of an average of 7 and 9 moles of ethylene oxide on technical Oleyl alcohol in a weight ratio of 20:80 to 80:20 grasslands. In a further preferred embodiment of the Invention is comprised of a mixture

• i) 10 to 25% by weight of a fatty alcohol polyethylene glycol ether of the formula (II) in which R ^{2 is} an alkenyl radical having 12 to 18 carbon atoms and n is a number from 5 to 10, and
• ii) 75 to 90 wt .-% 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

used. Mixtures of this type occur, for example the production of alkyl glucosides as an intermediate and can be used for stabilization without further cleaning of aqueous zeolite suspensions are used (DE 36 03 581 A1).

The introduction of the stabilizers into the suspension is un critical and can e.g. B. mechanically by stirring ren, if necessary at elevated temperatures of 50 ° C consequences. 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 wt .-% - based on the Suspension - can be added.

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

Examples

In a 500 ml beaker, an aqueous suspension of Zeolite A (Sasil®), solids content: 49.6% by weight, content of free alkali: 0.32% by weight, supplied by Henkel KGaA) and with each 1.5 wt .-% - based on the suspension - the stabilizer lisators or stabilizer mixtures - calculated as Solids - spiked.

Stabilizers used - examples according to the invention:
(30% by weight aqueous pastes):
A) adduct of an average of 1 mol of propylene oxide and 3 mol of ethylene oxide with octanol,
B) adduct of an average of 7.2 moles of ethylene oxide with a technical oleyl alcohol based on rapeseed oil (iodine number = 108),
C) adduct of an average of 9 moles of ethylene oxide with a technical oleyl alcohol based on rapeseed oil (iodine number = 108),
D) adduct of an average of 3 moles of ethylene oxide with a C ₁₆ Guerbet alcohol,
E) C _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) adduct of an average of 5 moles of ethylene oxide with isotridecyl alcohol,
H) adduct 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 over a period of 1 to 6 days assessed 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 beaker after decanting; Specification in% by weight based on the suspension.

The results are summarized in Tab. 1 and Tab. 2. The Examples 1 to 11 are according to the invention, Examples V1 to V4 are used for comparison. All percentages as% by weight.  

Table 1

Stabilization of zeolite A suspensions

Table 2

Stabilization of zeolite A suspensions (comparative tests)

Claims (10)

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 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 the R ² for an aliphatic hydrocarbon radical having 12 to 22 carbon atoms and 1, 2 or 3 double bonds and n for numbers stands from 1 to 10,
• c) fatty alcohol polyglycol ethers of the formula (III), in which R ^{3 represents} an alkyl radical having 6 to 10 carbon atoms, p represents numbers from 1 to 5 and q represents numbers from 3 to 15, and
• d) alkyl and / or alkenyl glycosides of the formula (IV), R ⁴ O- (G) _x (IV) in which R ^{4 is} an alkyl and / or alkenyl radical having 6 to 22 carbon atoms, G is a glycose unit, which is derived from a sugar with 5 or 6 carbon atoms, and x stands for a number between 1 and 10,

is formed, adds. 2. The method according to claim 1, characterized in that the nonionic surfactants aqueous suspensions of Zeolite A are added, the solids content of 20 have up 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 ether of the formula (II) is used in which R ^{2 is} an alkenyl radical having 16 to 18 carbon atoms and n is a number from 7 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% by weight of a fatty alcohol polyethylene glycol ether of the formula (II) in which R ^{2 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,

-% 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 nonionic surfactants in amounts of 0.1 to 5% by weight - based on the suspension - added.