JP2002538126A - Method for producing alkoxylated compound containing active hydrogen atom - Google Patents

Abstract

  (57) [Summary] The present invention relates to a method for producing an active hydrogen atom-containing alkoxylated compound. In the method, the catalyst comprises a hydrotalcite, which may be modified, and an alkali metal and / or alkaline earth metal hydroxide, oxide and / or alkoxide, alkali metal salt and / or alkaline earth metal salt, It is a mixture with a tin salt and a promoter selected from the group of mixed metal oxides.

Description

DETAILED DESCRIPTION OF THE INVENTION

TECHNICAL FIELD [0001] The present invention relates to a method for producing an active hydrogen atom-containing alkoxylated compound, in which the active hydrogen atom-containing alkoxylated compound may be optionally modified as a catalyst. With an alkylene oxide in the presence of and a selected cocatalyst.

BACKGROUND OF THE INVENTION An important group of nonionic surfactants is the alkylene oxides, especially ethylene oxide and / or propylene, which are usually produced by homogeneous catalysis in the presence of alkali metal hydroxides or alcoholates. It is an addition product of an oxide and a compound containing an active hydrogen atom. According to the homogeneous catalysis method, a product having a broad homolog distribution is obtained.

[0003] Products having a narrow homolog distribution ("products with a narrow distribution") can be obtained by carrying out the reaction in the presence of optionally modified hydrotalcite (eg DE- A-38 33 076). Unfortunately, hydrotalcite catalysts are very expensive as they are produced by elaborate methods, and as a result, the alkoxylation of active hydrogen atom containing compounds is quite costly.

DISCLOSURE OF THE INVENTION [0004] The problem addressed by the present invention is therefore an alkoxyl containing active hydrogen atoms which on the one hand leads to a narrow distribution of products and on the other hand a lower cost. To provide a process for the preparation of the fluorinated compound.

[0005] Surprisingly, the problem addressed by the present invention is surprisingly solved by at least partially replacing the optionally modified hydrotalcite with a specially selected cocatalyst. Can be. The present invention includes the observation that such catalyst mixtures also provide products having a narrow homolog distribution that closely matches the homolog distribution of the alkoxylation catalyzed by hydrotalcite alone. Furthermore, the total amount of catalyst can be reduced relative to the prior art. Finally, when using the catalyst mixture according to the invention, a clearly reduced reaction time is obtained.

DETAILED DESCRIPTION OF THE INVENTION The term “catalyst mixture” is taken to mean a mixture of hydrotalcite, optionally modified, and a selective cocatalyst (see below). Accordingly, the present invention relates to a method for producing an active hydrogen atom-containing alkoxylated compound by reacting an active hydrogen atom-containing compound with an alkylene oxide in the presence of optionally modified hydrotalcite as a catalyst. The method comprises the steps of preparing an alkali metal and / or alkaline earth metal hydroxide, oxide and / or
Alternatively, a co-catalyst selected from the group consisting of alkoxides, alkali metal salts and / or alkaline earth metal salts, tin salts and mixed metal oxides is used.

The compounds containing active hydrogen atoms can be selected, for example, from the following group of compounds: a1) Alcohols having 6 to 22 carbon atoms (so-called fatty alcohols). For example, capron alcohol, caprylic alcohol, caprin alcohol,
Lauryl alcohol, myristyl alcohol, cetyl alcohol, palmitoleyl alcohol, stearyl alcohol, isostearyl alcohol, oleyl alcohol, elaidyl alcohol, petroserinyl alcohol, linolyl alcohol, linolenyl alcohol, ricinolyl alcohol, eleostearyl alcohol, Aralkyl alcohol, gadreyl alcohol, behenyl alcohol, erucyl alcohol and their industrial mixtures obtained, for example, by hydrogenation of the methyl ester fraction of natural products or aldehydes from Roelen oxo synthesis. 12
Preferred are fatty alcohols having -18 carbon atoms, such as industrial coconut or tallow fatty alcohol fractions. Another group of suitable fatty alcohols are the so-called Guerbet alcohols, which are produced by alkali-catalyzed condensation of 2 moles of a fatty alcohol and can have from 12 to 36 carbon atoms.

A2) Carboxylic acids having 6 to 22 carbon atoms (so-called fatty acids) and hydroxy fatty acids. For example, caproic acid, caprylic acid, capric acid, lauric acid, myristic acid, palmitic acid, palmitoleic acid, stearic acid, isostearic acid, oleic acid, elaidic acid, petroselic acid, linoleic acid, linolenic acid, ricinoleic acid, eleostearin Acid, arachidic acid, gadolinic acid, behenic acid,
Erucic acid and, for example, these technical mixtures obtained by pressure hydrolysis of natural fats and oils. Fatty acids having 12 to 18 carbon atoms, such as industrial coconut or tallow fatty acids, are preferred.

A3) Adjacent hydroxy / alkoxy-substituted alkanes and secondary alcohols obtained by ring opening of epoxide compounds with alkylphenols, polyglycols, fatty amines, such as alcohols or carboxylic acids. Among the group of compounds containing active hydrogen atoms, alcohols or carboxylic acids having 6 to 22 carbon atoms are preferred.

The optionally modified hydrotalcite is used in the process according to the invention as alkoxylation catalyst in combination with a specially selected cocatalyst. For example, German patent applications DE-A1 38 43 713 and DE-A1 40 10 606 (Henkel
), Calcined or hydrophobized hydrotalcites are used as modified hydrotalcites. Calcined hydrotalcite is particularly preferred.

Suitable cocatalysts are hydroxides of alkali metals and / or alkaline earth metals,
Compounds from the group consisting of oxides and / or alkoxides, alkali metal and / or alkaline earth metal salts, tin salts and mixed metal oxides.

Particularly preferred alkali metal and / or alkaline earth metal hydroxides are lithium hydroxide and / or magnesium hydroxide. Of the group of alkali metal and / or alkaline earth metal oxides, magnesium oxide is preferred.

Preferred alkoxides of alkali metals and / or alkaline earth metals are short-chain alcohols, for example alcohols having 1 to 8 carbon atoms, especially alkoxides derived from methanol, ethanol and / or 2-ethylhexanol. is there. Magnesium compounds and / or barium compounds are particularly preferred.

Of the group of alkali metal and / or alkaline earth metal salts, magnesium and barium salts, for example carbonates such as magnesium carbonate or acetates such as magnesium acetate are of particular interest.

[0015] Mixed metal oxides are oxide compounds that contain at least two different metals. One metal is preferably magnesium. Other metals are aluminum,
It can be gallium, zirconium, indium, thallium, cobalt, scandium, lanthanum and / or manganese. Magnesium / aluminum mixed oxides are particularly preferred. The mixed oxides can be surface-modified with one or more of the cocatalysts mentioned, in particular with alkali metal and / or alkaline earth metal hydroxides and / or alkoxides. Magnesium oxide is a particularly preferred cocatalyst.

The optionally modified hydrotalcite is present in an amount of 0.01 to 5% by weight, preferably 0.05 to 0.5% by weight, based on the starting compounds (active hydrogen-containing compound and alkylene oxide). In particular in an amount of 0.05 to 0.2% by weight. The cocatalyst is present in an amount of 0.01 to 5% by weight, preferably 0.05 to 0% by weight, based on the starting compound.
It can be used in an amount of 0.5% by weight, in particular 0.1 to 0.3% by weight.

Due to the synergistic effect on the catalytic activity between the optionally modified hydrotalcite and the cocatalyst, the invention also makes it possible to reduce the total amount of catalyst compared to the prior art. That is, about 0.5 to 1% by weight of optionally modified hydrotalcite is commonly used for the alkoxylation of active hydrogen atom containing compounds. In one particularly preferred embodiment of the invention, the total amount of catalysts, including cocatalysts, is less than 0.5% by weight, preferably between 0.1 and 0.4% by weight, in particular between 0.1 and 0.4% by weight, based on the starting compound. Even between 2 and 0.3% by weight very good results can be obtained.

The ratio between the optionally modified hydrotalcite (catalyst) and the cocatalyst can vary over a wide range, preferably between 5: 1 and 1: 5, more preferably 3: It is between 1: 1 and 1: 3, especially between 2: 1 and 1: 2.

The reaction of the active hydrogen atom-containing compound with the alkylene oxide can be carried out by known methods at a temperature of 120 to 200 ° C., preferably 150 to 180 ° C. and a pressure of 1 to 5 bar. The amount of alkylene oxide added is not critical. The amount can be, for example, between 1 and 100 mol, preferably between 2 and 50 mol, in particular between 2 and 20 mol, of alkylene oxide per mol of active hydrogen in the compound. Ethylene oxide, propylene oxide and / or butylene oxide can be used as alkylene oxide, with ethylene oxide being preferred.

In the process of the invention, at least an equimolar amount of acid, based on the catalyst mixture (hydrotalcite and cocatalyst), can be added in order to completely destroy the catalyst mixture after the actual alkoxylation. Both inorganic and organic acids can be added as acids. Suitable inorganic acids are in particular mineral acids (for example, sulfuric acid, hydrochloric acid and / or phosphoric acid). Suitable organic acids are so-called fatty acids having from 6 to 22 carbon atoms and lower carboxylic acids having from 1 to 4 carbon atoms (only the carbon atoms of the hydrocarbon chain are counted; ), Which may optionally be further modified by hydroxyl groups. Preferred organic acids are lower carboxylic acids (eg, lactic acid, acetic acid and / or citric acid).

The acid is generally added as an aqueous solution, preferably as a 10-90% by weight solution. According to the invention, the acid is used in at least an equimolar amount, based on hydrotalcite, preferably in a molar ratio of 1: 1 to 10: 1, in particular 1: 1 to 4: 1, based on the catalyst.

In one advantageous embodiment of the invention, the acid is added at a temperature above the melting point of the alkoxylated compound, preferably at a temperature between 70 and 95 ° C. In practice, the addition of the acid is best carried out by maintaining the reaction mixture obtained after the alkoxylation at that temperature and adding the acid. The effect of the acid addition is that the catalyst mixture decomposes. The hydrotalcite decomposition mixture is water-soluble and does not lead to any clouding or precipitation of the alkoxylated compound.

If desired, an acid treatment can be carried out and then the catalyst can of course be recovered by known methods (eg by filtration). The alkoxylated compounds obtained by the process of the present invention have a narrow homolog distribution and can be easily used as nonionic surfactants for the manufacture of laundry detergents, dishwashing detergents and cleaners.

Example 1 638.3 g (= 3.3 mol) of a C _12/14 fatty alcohol mixture (about 70% by weight of C ₁₂ alcohol and about 30% by weight of C ₁₄ alcohol), calcined hydrotalcite 1 2.0 g (= 0.1% by weight, based on the starting compound) and 2.0 g of magnesium oxide
(= 0.2% by weight based on the starting compound) was introduced into the pressure-resistant reactor. 10 reactors
Evacuated at 0 ° C. for 30 minutes, then flushed with nitrogen. 361.7 g of ethylene oxide (
= 8.2 mol) were added in portions at a maximum of 180 ° C. and a maximum of 5 bar.
The reaction time was 70 minutes. After the alkoxylation, the reaction mixture was post-reacted at 120 ° C. for 1 hour and the reactor was evacuated at 120 ° C. for a further 30 minutes. An ethoxylated C12 / ₁₄ fatty alcohol (hydroxyl number 179) was obtained.

Comparative Example 1 The alkoxylation was carried out in the same manner as in Example 1, except that 5.0 g of hydrotalcite (= 0.5% by weight based on the starting compound) was used as a catalyst. The reaction time was 120 minutes. The product had a hydroxyl number of 182. The homolog distribution of the two products is comparable.

The examples show that when hydrotalcite is used alone (comparative example), large amounts of catalyst are required for equivalent products. In the process of the invention, a small amount of catalyst is sufficient. Furthermore, the reaction time is shorter in the method of the present invention.

────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Almut Forge D-40764 Langenfeld, Locher Weg 37 F-term (reference) 4H006 AA02 AB68 AC43 BA02 BA06 BA09 BA11 BA29 BA30 BA32 BA37 BA82 BA83 BC34 GN06 GP01 GP10 4H039 CA61 CL00

Claims (10)

[Claims] 1. A process for producing an active hydrogen atom-containing alkoxylated compound by reacting an active hydrogen atom-containing compound with an alkylene oxide in the presence of an optionally modified hydrotalcite as a catalyst. A co-catalyst selected from the group consisting of alkali metal and / or alkaline earth metal hydroxides, oxides and / or alkoxides, alkali metal salts and / or alkaline earth metal salts, tin salts and mixed metal oxides A method characterized by using. 2. The process according to claim 1, wherein an alcohol or carboxylic acid having 6 to 22 carbon atoms is used as the active hydrogen atom-containing compound. 3. The process as claimed in claim 1, wherein lithium hydroxide and / or magnesium hydroxide are used as cocatalysts. 4. The process according to claim 1, wherein magnesium oxide is used as a cocatalyst. 5. The process as claimed in claim 1, wherein alkoxides of alcohols having up to 8 carbon atoms, in particular magnesium alkoxides and / or barium alkoxides, are used as cocatalysts. 6. The process according to claim 1, wherein a mixed metal oxide containing magnesium is used as a cocatalyst. 7. The hydrotalcite, which may optionally be modified, is used in an amount of from 0.05 to 0.5% by weight, based on the starting compound.
The method according to any of the above. 8. The process as claimed in claim 1, wherein the cocatalyst is used in an amount of from 0.05 to 0.5% by weight, based on the starting compound. 9. The process as claimed in claim 1, wherein the sum of the optionally modified hydrotalcite and the cocatalyst is used in an amount of less than 0.5% by weight, based on the starting compound. The method according to any of the above. 10. The process according to claim 1, wherein after the alkoxylation, the catalyst is decomposed by adding an acid.