NO171630B - APPLICATION OF CALCINATED HYDROTALKITES AS CATALYSTS FOR ETHOXYLING BY PROPOXYLING OF COMPOUNDS WITH ACTIVE H ATOMS - Google Patents

Abstract

The use of calcined hydrotalcites as catalysts for ethoxylation or propoxylation of compounds having active hydrogen atoms results in a narrow bandwidth of the distribution of homologues among the ethoxylated and propoxylated products. <IMAGE>

Description

The present invention relates to the use of calcined hydrotalcites as catalysts for ethoxylation or propoxylation of compounds with active E atoms.

Hydrotalcite is a natural mineral with the ideal formula:

whose structure is derived from the structure of brucite (Mg(0H)2)« Brucite crystallizes in a layered structure with the metal ions in octahedral holes between two layers of close-packed hydroxyl ions whereby only every other layer of the octahedral holes is occupied. In hydrotalcite, some magnesium ions are replaced by aluminum ions, whereby the layered pack acquires a positive charge. This is balanced by the anions which, together with zeolitic crystal water, are in the intermediate layers. The layer structure is clear from the X-ray powder diagram (ASTM Card No. 14-191) which can be used for characterization.

Synthetically produced hydrotalcites are also known, which are described, for example, in DE-C 1 592 126, DE-A 3 346 943, DE-A 3 306 822 and EP-A 0 207 811.

In natural and synthetic products, the Mg<2+>:Al^<+->ratio can vary between approx. 1 and 5. Also the ratio 0H~:C03<2>~ can vary. Natural and synthetic hydrotalcites can be roughly described by the general formula I

whereby the conditions

1 < x < 5, y > z, (y + 0.5z) = 2x + 3 and 0 < n < 10 are valid. The difference in the composition of the hydrotalcites, especially with regard to the water content, leads to line shifts in the X-ray diffraction diagram.

Natural or synthetic hydrotalcites continuously emit water when heated or calcined. The dewatering is complete at 200"C whereby it can be demonstrated by X-ray diffraction that the structure of the hydrotalcite is still maintained. The further increase in temperature leads to the breakdown of the structure during the splitting off of hydroxyl groups (such as water) and carbon dioxide. Natural and according to different methods, for example according to the above-mentioned publications, artificially produced hydrotalcites exhibit a generally similar behavior when calcined.

Calcined hydrotalcites have already been used for various purposes, for example as absorbents and in the reaction of alkylene oxides with alkyl acetates for the production of mono-, di- and triethylene glycol ethyl ether acetate, see for example JP-A 56/36 431, mentioned in "Chemical Abstracts" 95(11)97 099m (1981).

Compounds with active H atoms for the purposes of the invention mean, for example, fatty alcohols, fatty acids and amines which, by ethoxylation or propoxylation, form non-ionic detergents. A typical example of this is the reaction of fatty alcohols with usually 10 to 18 carbon atoms with ethylene oxide and/or propylene oxide in the presence of catalysts whereby the fatty alcohols react with several molecules of ethylene oxide and/or propylene oxide.

Among others, the following are used as catalysts for the above-mentioned polyalkylation: Calcium and strontium hydroxides, alkoxides and phenoxides (EP-A 00 92 256);

Calcium alkoxide (EP-A 00 91 146);

Barium hydroxide (EP-B 0 115 083),

Basic magnesium compounds such as alkoxides (EP-A 00 82 569),

Magnesium and calcium fatty acid salts (EP-A 0 85 167).

The above-mentioned catalysts exhibit, among other things, the shortcoming that they are difficult to incorporate into the reaction system and/or difficult to manufacture.

Useful polyalkylation catalysts are further potassium hydroxide and sodium methylate.

For the fatty alcohol polyalkylate, a narrow bandwidth of the degree of polyalkylation is of particular importance, see for example "JAOCS", vol. 63, 691-695 (1986) and "EAPPI", 52-54

(1986). According to this, the so-called "narrow-range" alkoxylates in particular have the following advantages:

low pour point

- higher smoke point

- fewer moles of alkoxide to achieve water solubility less hydrotope for introduction into liquid universal detergent

less odor due to the presence of free (not converted)

fatty alcohols

reduction of "plumings" during spray drying of detergent slurries containing fatty alcohol polyalkoxylate surfactants.

It has now been found that by the invention's use of calcined hydrocalcites as catalysts, compounds with active E atoms can be polyalkylated with short reaction times and with high yields, and that the reaction products can be obtained with a narrow bandwidth, respectively homologous distribution, and with a distribution curve very close to that calculated according to Poisson.

For the purposes of the invention, calcined hydrotalcites are suitable which, before calcination, have a composition with formula I:

there

1 < x < 5, y > z, (y + 0.5z) =2x+3og0<n< 10.

Preferably x has the value 1.8 to 3.

The calcined hydrotalcites used according to the invention have the advantage that they can be easily incorporated into the reaction mixture and, due to their insolubility in the reaction mixture, can be easily removed by simple precautions. However, they can also remain in the reaction mixture when their presence does not interfere with the further use of the reaction products.

According to a preferred embodiment of the invention, the compound with active H atoms is selected from the group comprising fatty acids, hydroxy fatty acids, fatty acid amides, alkanols, alkylphenols, polyglycols, fatty amines, fatty acid alkanolamides or vicinal hydroxy, alkoxy-substituted alkanes.

Examples of compounds that can be alkylated using the calcined hydrotalcite of the invention are listed below:

Fatty acids:

Fatty acids with 8 to 22 carbon atoms of natural or synthetic origin, in particular straight-chain, saturated or unsaturated fatty acids including technical mixtures thereof, as obtained by cleavage of animal and/or vegetable fats and oils, for example from coconut, palm kernel, palm -, soya, sunflower, beet, cottonseed or fish oil, beef tallow and lard, special examples are capryl, caprine, laurine, laurolein, myristin-myristolein, palmitin, palmitolein, oil, elaidin -, arachinic, gadoleic, behenic, brassidic and erucic acids; further methyl-branched saturated and unsaturated fatty acids with 10 to 22 carbon atoms that arise from dimerization of the corresponding unsaturated fatty acids as by-products, and monocarboxylic acids with 1 to 7 carbon atoms.

Hydroxy fatty acids:

Natural or synthetic hydroxy fatty acids and especially those with 16 - 22 carbon atoms, for example ricinol or 12-hydroxystearic acid.

Fatty acid amides:

Derivatives of the above-mentioned straight-chain, saturated or unsaturated fatty acids with ammonia or primary aliphatic amines with 1 to 4 carbon atoms in the aliphatic substituents.

Alkanols:

Saturated or unsaturated alkanols, especially hydrogenation products of the above-mentioned straight-chain, saturated or unsaturated fatty acids, respectively derivatives thereof such as methyl esters or glycerides; aliphatic or cyclic alkanols of 2 to 6 carbon atoms, for example ethanol, propanol, butanol, hexanol and cyclohexanol; including the guerbet alcohols derived from the above-mentioned monoalkanols.

Alkylphenols:

Mono-, di- or trialkylphenols, especially with 4 to 12 carbon atoms in the alkyl groups.

Polyglycols:

Polyethylene or polypropylene glycols (average degree of polymerization 2 to 2,000).

Fatty amines:

In particular, primary fatty amines which are available from nitriles of the above-mentioned straight-chain, saturated or unsaturated fatty acids or the corresponding fatty alcohols; furthermore also mono- and dialkylamines with C 1-4 alkyl groups.

Fatty acid alkanolamides:

Derivatives of the above-mentioned straight-chain, saturated or unsaturated fatty acids with mono- or dialkanolamines, especially mono- or diethanolamine.

Vicinal Hydroxy-Alkoxy Substituted Alkanes: Ring opening products of 1,2-epoxyalkane mixtures with 12 to 22 carbon atoms in the chain with polyhydric alkanols with 2 to

12 carbon atoms and 2 to 6 hydroxyl groups.

The derivatives produced according to the invention using calcined hydrotalcites are commercially available products so that no further explanation is necessary. They are generally prepared by ethoxylation and/or propoxylation of starting compounds which exhibit active hydrogen atoms. Typical representatives are, for example, an addition product of 9 mol of ethylene oxide on coconut oil fatty acid, an equivalent of 2 mol of ethylene oxide on a fatty alcohol mixture with chain length Ci2-14" an equivalent of 3 mol of ethylene oxide and 8 mol of propylene oxide on a fatty alcohol mixture with chain length C12-I8' a corresponding of 10 mol of ethylene oxide on nonylphenol, an equivalent of 7.3 mol of ethylene oxide on glycerol, an equivalent of 10 mol of ethylene oxide on a diol mixture which was obtained by reacting a 1,2-epoxyalkane mixture of chain length C^2-16 with ethylene glycol, a equivalent of 12 moles of ethylene oxide on a fatty amine mixture with chain length C^0-18°S an equivalent of 4 moles of ethylene oxide on coconut fatty acid monomethanolamide.

According to a further advantageous embodiment of the invention, the calcined hydrotalcites are added in an amount of 0.1 to 2% by weight, calculated on the end product of the ethoxylation or propoxylation, to the reaction mixture.

The calcined hydrotalcites to be used according to the invention can be obtained from the natural or synthetic hydrotalcites with several hours of heating to temperatures above 100°C, particularly preferred are calcination temperatures from 400 to 600°C.

The invention shall be illustrated in more detail below by means of preferred embodiments, whereby reference is made to the drawings. The drawing shows the intended homologous distribution according to some examples compared to that which can be achieved using sodium methylate.

Example 1

A commercially available synthetic hydrotalcite was calcined for 8 hours at 500°C.

For the reaction of one mole of a commercial lauryl alcohol with 6 moles of ethylene oxide, the lauryl alcohol was added to a pressure reactor and thereto was added 0.5 wt-#, calculated on the intended final product, of the previously obtained calcined hydrotalcite. The reactor was washed with nitrogen and evacuated for 30 minutes at a temperature of 100°C. Finally, the temperature was raised to 180°C and the desired amount of ethylene oxide was added under a pressure of 4 to 5 bar. After the reaction was complete, the whole thing was left to react for 30 minutes. After filtering off the suspended catalyst, the desired reaction mixture was obtained, the characteristic data of which appear in table 1.

Examples 2 to 13

Analogously to what is described in Example 1, the compounds listed in Table 1 with active H atoms were reacted using calcined synthetic hydrotalcites with ethylene oxide. The compounds used, the converted amounts of ethylene oxide, the calcination conditions for the hydrotalcites, the catalyst concentration, the reaction time for the ethoxylation and the OH numbers for some of the ethoxylation products obtained are indicated in Table 1 for some compounds. Furthermore, table 1 shows for certain compounds in which drawing the obtained homologous distributions are reproduced in comparison with sodium methylate.

In examples 1, 2, 6 and 7, calcined hydrotalcites were used, where the atomic ratio Mg:Al (corresponding to x in the general formula given above) was 2.17. For the calcined hydrotalcites in Examples 3, 4 and 8 to 13, the Mg:Al atomic ratio was 2.17 and in Example 5 the ratio was 2.08.

Claims (5)

1. Use of calcined hydrotalcites which, before calcination, have a composition of formula I: there l<x<5, y>z, (y + 0.5z) = 2x + 3 and 0 < n < 10 as catalysts for ethoxylation and propoxylation of compounds with active H atoms 2. Use according to claim 1, where the compounds with active H atoms are selected from the group of fatty acids, hydroxy fatty acids, fatty acid amides, alkanols, alkylphenols, polyglycols, fatty amines, fatty acid alkanolamides or vicinal hydroxy-alkyl substituted alkanes. 3. Use according to claim 1 of hydrotalcites with the general formula I: there x is a number from 1.8 to 3 and y and z are as indicated above. 4. Use according to claim 1 where the hydrotalcite is calcined at temperatures between 400 and 600°C. 5. Use according to claim 1, where the calcined hydrotalcites are used in an amount of 0.1 to 2 weight-# calculated on the end product from the epoxylation or the propoxylation.