DE2213155A1 - Method for the treatment of alpha-sulfofatty acids - Google Patents

Description

PATENT LAWYERS

DR. ING. A. VAN DER WERTH DR. FRANZ LEDERER

21 HAMBURG 9O 8 MÖNCHEN 8O

WILSTOKFEK STR. S3 · TEL. (04 11) 77 OS 61 LUCILE-GRAHN-STR. 33 ■ TEL. ΙΟβ 11) 47 39 47

Munich, March 8, 1972 C 460

Unilever N.V., Museumpark 1, Rotterdam, the Netherlands

Method for the treatment of <? C ~ sulfo fatty cures

The invention relates to an improvement in the process for the rapid and continuous sulfonation of fatty acids.

It is desirable that sulfofatty acids have a good color, especially when they are to be used in surface-active agents, for example detergents. However, it is known that sulfo fatty acids produced by continuous processes using SO2 / diluent gas as the sulfonating agent, namely with stirring in containers or by means of thin-layer processes, are not color-stable. In the thin-layer process, the fatty acid to be οί-sulfonated runs as a liquid, thin layer along the walls of the reactor and is there brought into contact with an excess of SO ~ gas that is diluted with an inert gas. It has been proposed to improve the color stability of the product by carefully controlling the reactor conditions, namely the temperatures of the raw materials and the reaction itself as well as the

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Concentrations and dwell times> to 'improve. It is It has also been suggested that the (tf-sulfo fatty acid product at Exit from the reactor to cool quickly.

Presumably the cause of the impairment lies in the fed in SO ^ amount, since the <x -sulfofatty acid product this process constantly with remaining, unreacted SO ,, with the dissolved SO, and with in the course of the sulfonation processes formed, dissolved sulfonic anhydrides reacts. The SO, amount cannot be reduced. It is well known in all continuously operating sulfonation reactors, an excess of SOrr is required to provide the driving force for to maintain the mass transfer and the reaction.

The problem of color deterioration becomes acute when the sulfonation products of the fatty acids have to be stored, even if it is only a few hours. In the case of technically customary processes, the oc-sulfo fatty acid product may have to be stored in the acid form. In the case of factory use of the product, for example, during the individual
management between / "" companies there is a storage time between the production of the <x -sulfo-fatty acid and its use.

It has been proposed to store the ot-sulfo fatty acid product in the form of a neutralized paste. However, difficulties arise here because of the high viscosities at solids contents of over 30 to 35 percent.

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The object of the invention is to provide a process for the treatment of the -sulfo fatty acid product from sulfonation reactions so that the acid can be stored for at least 3 days without serious damage to the color. The color deterioration is measured in practice based on its bleachability under commercial conditions. Here, it is understood by "serious color interference" that, by means of hypochlorite is possible under the following conditions, no bleaching at acceptable color values (namely, lower than 500 Klett units): The <* - sulfofatty acid is neutralized with hot (70 to 9O ⁰ G), aqueous sodium hydroxide containing the required amount of sodium hypochlorite (generally 3 to 5 percent active chlorine, based on the amount of the (X-SuIfofettsäure). the acid may also initially with aqueous sodium hydroxide at 70 neutralized to 90 ⁰ C and then at 8O ⁰ C with With either method, the bleaching process should be over after 1 hour.

Thus, the invention relates to a method for treating (X -sulfo fatty acids obtained by sulfonation using of SO, / diluent gas, the CX-sulfofatty acid product being an alkylbenzene with 1 to 18 carbon atoms is incorporated in the alkyl radical.

Preferably, the alkylbenzene is added substantially immediately after the product leaves the sulfonation zone, i.e. added within 1 to 5 minutes. However, the addition can be delayed up to about 1 hour without

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that there is a noticeable reduction in the beneficial effect.

It has been shown that the ot-sulfo fatty acid in the product by incorporating the alkylbenzenes as soon as possible after leaving the sulphonation zone, before the content of reactive and color-forming components, i.e. SG, and sulfonic acid anhydrides, is protected, has a much better color and is more stable in storage. The storage of the oC sulfo fatty acid product per se in molten, liquid form or solid form offers the advantage of significantly reduced storage space, simpler equipment and easy transport from one storage place to another. The stored oC sulfo fatty acid product can be neutralized / bleached in a conventional manner, either gradually or simultaneously, by e.g. aqueous sodium hydroxide or sodium hypochlorite before mixing in surfactants.

Suitable alkylbenzenes have 1 to 18 carbon atoms, preferably 9 to 15 carbon atoms, in the alkyl radical. The alkyl radical can be linear or branched. The commercially available "Dobane 055 (RTM)" from Shell Chemicals Limited is preferably used as the alkylbenzene. It is assumed that this alkylbenzene has an average molecular weight of 254 and the following distribution in the number of carbon atoms: G ₁ C 1 $;

C ₂₀ 21 % and C ₂₁ 12 #.

In the following the application of the invention to usual Sulphonation reactors that work on the principle of the descending thin film / SO, gas ^ described.

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In the process of US Pat. No. 3,350,428 (Ghemithon 'method) the sulfonation product is preferably immediately at Leaving the reaction zone by quenching with the same Sulphonic acid in a recycle system or by means of heat exchangers chilled. When applying the invention to the Chemithon process, the oC sulfo fatty acid product is at Leaving the reaction zone in the recycle system is quenched with a cold solution of the alkylbenzenes in the <X-sulfofatty acid. This is followed by the usual process steps in a Chemithon process, i.e. the separation of remaining, non-rumg ^ set SO *, e.g. by centrifugation; ren or, in the case of the reaction of residual sulfonic acid anhydrides with the alkyl benzene, by digestion. The alkylbenzene can optionally be recycled, i.e. after about 15 minutes, instead of at the beginning of the recycle ^ added will. When the cooling, the separation and digestion— ' steps are carried out according to the Chemiton process, the oc-sulfo fatty acid product necessarily remains longer Time in the acidic form, without protection from the inevitable content of SO and sulphonic anhydrides. When using the The method according to the invention is the (X-sulfofatty acid by the alkylbenzene protected, preferably with the SO, and. reacts to the anhydrides.

In the Allied Chemical Corporation process, the sulfonation product is collected in a specially constructed separator with fixed _{blades which, by means of centrifugal force, separate the liquid product from the remaining SO 5} gas. The invention can be applied

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this process by adding the alkylbenzenes to the <rt-sulfofatty acid product apply as early as possible, e.g. by removing the alkylbenzene in the separator or, optionally, in an additional vessel or one Transport line running between the lower end of the reaction zone and the separation device containing the o <-sulfo fatty acid product must go through, is located, is present. The alkylbenzene and product are mixed and come together into the separator.

The invention can also be applied to SO ^ / gas sulfonation reactions use in stirred tank reactors; in this case, however, the incorporation of the alkylbenzenes should not last longer than 1 hour, be delayed by the formation of the sulfate of fatty acid.

The invention relates in particular to an improvement in the continuous process for the <X-sulfonation of long-chain, saturated monocarboxy fatty acids of the formula RCOOH, in which R is an alkyl radical with 7 to 21 carbon atoms. Preferred Fatty acids are hardened tallow, palm oil, coconut and fish oil fatty acids as well as synthetic fatty acids.

Is the <X-sulfo fatty acid for use in one If detergent is used, an alkylbenzene is preferred used, which is after sulfonation or sulfation by the remainder SO, and / or sulfonic anhydrides directly can be used in water, such as dodecylbenzene.

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The alky! Benzene should be added in such an amount that a reaction with all of your remaining SO, and the sulfonic anhydrides is possible. In the SO, / Luft-Yerfahren for Sulfonation of fatty acids, the amount is in the sizes * - order of 0.5 to 10 percent by weight of the sulfonic acid, preferably under 5 percent, as some detergents, -the Sodium - «- sulfofatty acid treated according to the invention, can become sticky during manufacture. Me presence the larger amount of alkylbenzenes results in a residual hydrocarbon content, which is foam-inhibiting can work.

The invention also relates to detergents containing a salt of a treated according to the method of the invention oC-sulfofatty acid contain.

The examples explain the invention

Examples 1 to 4

A vertically mounted reactor made of stainless steel is used, which works on the principle of the descending ring-shaped thin layer and is 2.44 m long, ■

a clear width of 2.03 cm and a water-cooled one Has cooling jacket. The fatty acid to be sulfonated is through an annular opening at the top of the inner wall of the reactor tube at a rate of 22.68 kg / hour. fed in, so that a film is coming down on the wall. At the top of the reactor, SO diluted with air (4 percent SO, in air)

2 0 9 8 A 0/12 0 8

fed, which runs down simultaneously with the fatty acid the wall werden.und wherein 1 to 1.4 mol of SO used, per mol of fatty acid, the cooling water temperature is about 13O ⁰ C. (1.1 mol SO, give about 82 percent "conversion", 1.35 mol SO, give about 95 percent "turnover". "Conversion" is understood as the amount of fatty acid (in percent) that is converted into the o <-sulfo fatty acid will.)

The aforementioned conditions are chosen so that an essentially complete sulfonation is obtained at the time at which the fatty acid reaches the bottom of the reactor. The oC sulfo fatty acid product is removed from the reactor removed by means of a gas / liquid separation device and immediately added the specified amount of "Dobane 055 (RTM)".

The mixture of the oc-sulfo fatty acid product and "Dobane 055 (RTM) ”is stored at 75 ° C. so that the mixture is present as a melt Samples are taken and neutralized with 3% sodium hydroxide solution (i.e. unbleached). The color comes with a Standard Klett Summerson colorimeter with a blue filter No. 42 measured using an aqueous solution with 5 percent • active detergent in a 4 cm cuvette. In In the examples, the percentages are percentages by weight "Dobane 055 (RTM)", based on the rt-sulfofatty acid product. The comparison tests are marked with * 0 *.

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Examples No. 1 and 2 for paint after storage in hours

95 percent sales

0 o (-sulfofatty acid-. product alone

1 crt sulfo fatty acid product + $ 5

C <X sulfo fatty acid product alone

2 <x -sulfofatty acid

product + $ 5> 0 0.25 0.5 1.0 2.0

24

10800 10100 9900 10500 10500 14300

10900 10700 10500 9700. 10500 10000

9100 11100 9700 10900 10700 11100

5500 7900 6600 7200 7900 7900

Example No. 3 at 95 percent conversion

0 <x -sulfofatty acid product alone

OC-SuIf of fatty acid product + 1%

<X -sulfo fatty acid product + 3 #

a-sulf of ett acid product +

Color after storage in days 1 7 14 21

9400 16350 19000 22000 12100 9700 14400 14500 20200 18100 9500 10400 12500 16750 15000 9900 9700 11800 15250 13600

Example no. 4 at

Color after storage in days

80 percent sales 0 7th 14th 21st 0 «K-sulfofatty acid
product alone 7650 9250 14500 18500 CX ₁ -SuIf of ett acid-
product + $ 1 6000 8500 I3IOO 18500 a-sulfofatty acid
product + 396 4980 7750 5000 14300 oc-sulf of fatty acid
product + 5 # 4500 7500 6300 12200

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The neutralized products obtained from Examples 1 to 4 can be obtained by oxidative bleaching using of aqueous sodium hypochlorite with 5 percent effective chlorine in an amount determined by the amount of sulfo fatty acid will be bleached.

Example5

The product of the process of the invention according to Examples 1 to 4 can be used in powder detergents

to use for the preparation of the powder without adversely affecting the other ingredients and without difficulty. Typical detergents are described in GB-PA 11 332/71 and 45 162/71.

Claims

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Claims (4)

Claim, e Process for the treatment of c ^ -sulfo fatty acids, the By sulfonating fatty acids using SO2 / diluent gas as the sulfonating agent are characterized in that the <X-sulfofatty acid within 1 hour after its manufacture position an alkylbenzene with 1 to 18 carbon atoms in the alkyl radical is added. 2. The method according to claim 1, characterized in that the alkylbenzene is added within 1 to 5 minutes. 3. The method according to claim 1 or 2, characterized in that the alkylbenzene in an amount of 0.5 to 10 percent by weight, preferably up to 5 percent, based on the α-sulfo fatty acid, is present. 4. The method according to any one of the preceding claims, characterized in that the alkylbenzene has 10 to 15 carbon atoms in the alkyl radical and is preferably dodecylbenzene. 209840/1208