CS214067B1 - A process for the preparation of low water content olefin sulfonates - Google Patents

Description

The invention relates to a process for producing higher olefin sulfonates with a low content of alkene by-products from a process comprising the sulfonation of alkenes with sulfur trioxide gas, alkaline hydrolysis of the sulfonation products, optional bleaching and pH adjustment of the product.

Surfactants produced by the sulfonation of higher alkenes are referred to as olefin sulfonates. Nej-; the most important of these are alpha olefin sulfonates, which have excellent application properties when used in detorgeins and are perfectly and rapidly biodegradable. The importance of alphaolefinsulfonates has recently increased as a result of the industrial availability of the starting material - higher linear 1-alkenes (alphaolefins) - and the finding that the most widespread surfactant, linear alkylbenzene sulfonate, is not yet perfectly biodegradable. Less important are olefin sulfonates produced from higher alkenes with a double bond on the internal carbons of the hydrocarbon chain (the so-called internal alkenes). Also, 2-alkyl-1-alkenes are sulfonated to produce olefin sulfonates. The latter two types of alkenes are used in the production of olefin sulfonates most often by their presence in mixtures with a predominant proportion of 1-alkenes, and only exceptionally can be used alone.

Olefinine sulfonates are always a mixture of a number of compounds. Sulfonation of 1-alcons with sulfur trioxide produces alkanesultones and alkonsulfonic acids. By alkaline hydrolysis, the sultones give a mixture of hydroxyalkane sulfonates and alkene sulfonates. In addition to the monosulfonated compounds, sulfonation produces compounds with two sulfur-containing groups, and from them, by alkaline hydrolysis, disulfonates and sulfosulfonates are formed whose exact structure

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214 067 is not fully established. The formation of by-products is illustrated by the approximate reaction scheme:

R-CH-CH ₂ -S0 ₃ Na

0S0 ₃ Na

R-CH (CH ₂ ) _n CH ₂ —SO 5 NaOH;

n = predominantly 3 hydroxyalkane sulfonate sulfate sulfonate

In alpha-olefin sulfonates, 36-47% of alkene sulfonates, 29-36% of hydroxyalkane sulfonates and 17-35% of compounds with two sulfur-containing groups (ie disulfonates and sulfosulfonates) are usually present from surfactants. As additional ingredients, unreacted alkenes are present in an amount of from 1 to 10% for the content of active substances and alkanesultones in an amount of usually from 100 to 10 000 mg per kg of active substances. In addition to these defined substances, small amounts of colored substances of unknown structure and inorganic impurities are present, mainly sodium sulfate and sodium chloride.

Other highly undesirable trace admixtures in alpha-olefin sulfonates may be unsaturated alconsultones and chloroalkanesultones. These compounds have been found to induce allergic sensitization. They can be formed by bleaching with alkali hypochlorites as a result of the addition of hypochlorous acid to ulkensulfonates to form chlorohydroxyalkane sulfonates, which by closing the sultone ring can produce chloroalkane sultones and from them by dehydroehlorination can give alconsultones (D, S. CONNOR sespol. (1975/25),

Similarly to the preparation of alpha-olefin sulfonates from 1-alkenes, the reactions take place in the production of olefin sulfonates from internal alkenes and the composition of the products is similar. However, these products contain sulfone groups attached to the secondary carbons of the chain and have less desirable application properties.

It is known that with increasing proportions of non-sulphonated alkenes in alpha-olefin sulphonates, the dispersing efficacy of these tonsides decreases (WJ DEWITT, J. Am. 011 Chem. Soc., 55 (1972/363)). compounds with two sulfur-containing groups (I. YAMANE, J. Am. Oil. Chem. Sec., 49 (1978/81). Also, the higher alkanesultone content is now considered to be a serious defect in the quality of alpha-olefinsulfonates because they are considered toxicologically suspect (J. CALLAHAN, L. GILDENBERG, N. OMELCZENKO. J. Am. Oil. Chem. Soe. 54 (1976/343).

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All practically significant production processes for breast olefin sulfonates consist essentially in the sulfonation of alkenes with sulfur trioxide and subsequent hydrolysis of the sulfonation products.

The presence of by-products in the resulting surfactants has so far been neglected. The choice of critical sulfonation conditions, in particular the determination of the molar ratio of sulfur trioxide to alkene, was based on the need to simultaneously meet two contradictory requirements: to achieve a high alkene conversion> resulting in higher molar ratios, ratios. Suitable molar ratios are in a very wide range from 0.8 to 1.5 to 2 (e.g., U.S. Pat. No. 3,444,087,

DOS 2,307,306, British, Pat. No. 1,357,606, U.S. Pat. 3,492,239). In practice, however, sulfur trioxide has been used in excess so that the products after hydrolysis can be decolorized to commercially light products by the addition of alkaline solutions of hypochlorite. The content of compounds with two sulfur-containing groups was disregarded and such products contained 20-30%. When sulfonated in excess of alkene, the products were lighter and the content of products 8 by the two sulfur-containing groups was substantially lower. However, unreacted 1-alkene had to be recovered from the products to achieve good yields and good product quality. This was accomplished by extracting the hydrolyzed products with organic solvents. However, this process was difficult due to the considerable solubilization of the solvents in the surfactant solutions. There were losses in both solvents and alkenes. Another sulfonation process with excess alkenes is based on the finding that at high hydrolysis temperatures (around 270 ° C), unreacted alkene can be separated relatively perfectly from the surfactant solution in the treatment of such sulfonation products. At the same time, the majority of the colored compounds and the sulphones present are transferred to the alkene phase (F. PRAUN, K. KOSSWIG, Fette, Seifen, Anstrichmittel. 76 (1974/318). The disadvantage of this procedure is difficult control of the alkene separation process, high hydrolysis temperatures and intensive purification of recycled alkenes, which is still not as good as the starting material because of isomerization.

Alkenes sulfonation products can be converted to sulfonic acids by acid hydrolysis (DAS 1214617; DAS 1215695; French Pat. 1,419,652; French Pat. 1,421,804; H. BAUMANN, W. STEIN, M. VOSS, Fette, Seifen , Anstrichmittel, 72 (1970/247) In acid hydrolysis, a higher proportion of alkenesulfonic acids is formed in alkali sulfonic acid products compared to alkaline conditions, which should be advantageous for the application properties of the olefin sulfonates formed. dark and difficult to discolour, smell, the reaction mixture is extremely corrosive at hydrolytic temperatures and the conversion of sultones to sulfonic acids is never as high as that of alkaline hydrolysis, the acid hydrolysis products contain 10 to 100 times more sultones.

A common process used to convert alkene sulfonation products to sulfonates is by alkaline hydrolysis in the presence of an alkali hydroxide, with temperatures of from 100 to 200 ° C being suitable (e.g. U.S. Pat. No. 3,488,384; U.S. Pat. No. 3,641). 131,

In these procedures, small residual amounts of sultones, less than 0.5 to 0.1%, were not considered to be serious and were not determined. Hydrolysis perfection was only required by the requirements for achieving good surfactant yields. Higher hydrolysis temperatures were considered useful only to achieve higher hydrolysis rates and to achieve

214,067 short reaction times; Commonly used hydrolysis temperatures were between 140-160 ° C and the required reaction time was 10-30 min. The presently required limits of 10-50 mg alkanaultones per kg of surfactant cannot be achieved under these conditions. In order to reduce the sultone content by water, the aforementioned oxtraction processes and the use of special solvents or unaggregated alkenes separated in the hydrolysis at high temperature. The disadvantages of these processes have already been discussed.

In the processes described above, olefin sulfonates in the form of solutions have generally been stripped of coloring agents by the action of oxidizing agents. This bleaching was carried out most efficiently and most often by mixing olefin sulfonate solutions and alkaline hypochlorite solutions and heating to 40-60 ° C (0 U. MARQUIS, Hydrocarbon Processing 47 (1968/3, 109; MS.

172,421 (1975)). Hydrogen peroxide could also be used as a less effective bleaching agent. After alkaline hydrolysis, an excess of alkali hydroxide has normally reacted in the surfactant solution. This excess had to be reduced before bleaching because the bleaching efficiency of hypochlorite increases with decreasing pH. On the other hand, as the pHf decreases, the concentration of hypochlorous acid increases in the hypochlorite solutions, and this increases the possibility of the formation of eensibilizing chloroalkane and alkenesultones. These circumstances require a compromise and relatively accurate pH adjustment during bleaching. However, this has been difficult to achieve due to the low pH-buffering capacity of such surfactant solutions in the desired range, i.e. between pH 8-10, 5, and for the presence of free alkali hydroxide in hypochlorite solutions. During bleaching, the pH was not sufficiently stabilized and the cell was in a more acidic region, leading to the formation of sulton-sonsibilizing or in a strongly basic region with little to no bleaching activity. However, even for hydrogen peroxide bleaching, a certain pH is required, and so this process has led to similar drawbacks. For commercial solutions or aqueous olefin sulfonate dispersions, a pH between 7 and 8.5 is required. For hypochlorite bleaching, it was therefore necessary to include a further pH adjustment or to store alkaline products and to treat them prior to shipment. However, the storage of more alkaline olefin sulfonate solutions, even in alloys of alloyed cereals, has led to darkening and thus to degradation of the products.

In some cases, it is not necessary to bleach olefin sulfonate solutions, then only after hydrolysis neutralizes excess alkali hydroxide and adjusts the pH to the desired value. However, even in this case, the insufficient buffering capacity of these solutions is disadvantageous, especially in continuous production processes where acid is neutralized by automatic pH according to the pH value, and this process becomes unmanageable.

A new process for the production of surfactant olefin sulfonates and a low content of alcon by-products has now been found by the process involving the sulfonation of alkenes with sulfur trioxide gas, diluted air or other inert gas to a concentration of 1.5 to 15 mol * SOg at 25 to 120 ° C, alkaline hydrolysis eulphonation products, possible bleaching and pH adjustment of the product, characterized in that sulfur dioxide in excess of 2 is used for the sulphonation of alkenes and the number of carbon atoms in the molecule of 12 to 20, preferably 14 to 18, and an average molar mass of from 200 to 250 g / mol. up to 35 moles X, the sulphonation product, before the actual hydrolysis of the emission and the alkaline hydroxide solution and the aluconine solution having pH buffering properties, are preferably applied. and an alkali metal salt of the fatty acid, the amount of alkali hydroxide being 0.9 to 1.2, the amount of buffering compound 0.01 to 0.2 mol per mole eho244 067

Olefinine sulfonates are generally required to be bleached. Although the products according to the invention produce relatively light products, bleaching with alkaline hypochlorite solutions or hydrogen peroxide leads to a reduction in color. The possible bleaching can be carried out directly in the process according to the invention directly after hydrolysis using a buffering capacity which re-results after hydrolysis, while the pH of the solution of the elephinsulfonate remains constant after addition of the alkali hypochlorite containing free alkaline hydroxide. Thus, hypochlorite can be easily bleached in a pH range of between 8 and 10.5, preferably between 9 and 10. This leads to a reduction in the presence of hypochlorous acid and to the possibility of the formation of sonsibilizing chlorinated and unsaturated sultones. Hydrogen peroxide bleaching also leads to a pH shift and in the process according to the invention the pH transfer again is negligible due to the presence of a damping capacity. However, hydrogen peroxide bleaching is less effective and results in long-term foam development in olefin sulfonate solutions. When bleaching hypochlorite solutions, the best approach is to add to the olefin sulfonate solution, after hydrolysis with pK 9.5, a sodium hypochlorite solution with a concentration of 140 to 150 g of active chlorine per liter, in an amount between 2 to 15 kg of hypochlorite solution per 100 kg of about 35% olefin sulfonate solution. The temperatures in this mixing can be between 25 and 80 ° C. After mixing, the resulting solution is heated to a temperature between 45 to 80 ° C for 20 to 120 min. If it is necessary to adjust the pH of the olefin sulfonate solution, it can be easily controlled in the process according to the invention and the pH reached is stable even during storage.

The process according to the invention has a number of advantages over the prior art processes. Above all, it is the reduced content of by-products in the product. The reduction concerns less surfactant sulfosulfonates and disulfonates, toxicologically suspected alkanesultones and chlorinated sultones, and unsaturated sultones that cause allergic sensitization. The process according to the invention does not have the difficult technological sections of the prior art and allows easy continuous configuration and automatic process control. The olefin sulfonates have superior application properties over products manufactured by known methods, are guaranteed a high degree of toxicological safety and have improved storage properties. The new process makes perfect use of raw materials, as compared to known processes, it has no losses due to recirculation and regeneration of raw materials and does not require auxiliary chemicals such as solvents, and avoids losses associated with their use and recovery.

Example 1.

A reactor for the continuous sulfonaoi in descending film was sprayed on the inner wall of the tube of internal diameter 6 mm and length of 1200 mm the mixture of linear 1-alkenes C _g and C _lg of average molecular weight 234 g / mol rate of 468 g / h (2 moles / h). Sulfur dioxide gas, diluted with air to a concentration of 3 mol, was fed in parallel. % at 180 g SOg / h (2.25 mol / h). The reaction tube was maintained at 30 ° C by circulating tempered water in the reactor outer jacket. After passing through the reactor, gas was separated from the sulfonation product in a separator. This was further processed in a batch process. The sulfonation product had a saponification number (determined after 2 h boiling with an excess of potassium hydroxide solution of c (KOH) = 0.1 mol / 3.39 meq / g, corresponding to the acidity of the sulfonation product and the acid released by hydrolysis). found 3.6% of unreacted 1-alkene corresponding to 95% alkene conversion. 100 g of the sulfonation product was mixed with a solution of 13.3 g of sodium hydroxide in 100 g of water and a β solution of 3.6 g of sodium carbonate.

214 067 also use dilute solutions and thus simultaneously add to the process the water needed to obtain products with the usual commercial concentrations of blades of 30 and 40% active ingredients. Usually it is preferable to dispense water mastered. A wide variety of compounds which exhibit these pH properties between 7 and 10.5 can be used as compounds with pH-buffering properties. These buffering agents can be dosed as such, i.e. in the form of alkali salts, or may be formed in situ, e.g. by dosing the appropriate acid, which together with the aforementioned alkali hydroxide solution stream forms a buffer solution of the respective alkali salt. Particularly suitable are salts of polyhydric inorganic or organic acids, such as: phosphates, carbonates, borates, citrates. However, it is also possible to use alkali salts of monohydric acids such as: acetates, formates. The added amount of alkali hydroxide and buffer must neutralize the free sulfonic acids present and a small amount of the full sulfuric acid or sulfur trioxide in the sulfonation product and, moreover, sulfonic acids formed only during the hydrolysis itself, in particular as a result of the hydrolysis of the sultones. In addition, at least a portion of the pH buffering compound must still be present after hydrolysis to provide the necessary pH and buffering capacity for further processing. A part of the alkali hydroxide can be replaced by a pH buffer, but for economic reasons it can be only a small part, therefore at least 0.9 moles of alkali hydroxide per mole of chemical equivalents of acidity are envisaged herein. The mixing of the sulphonation products with aqueous solutions of alkali hydroxides and with buffer solutions, optionally with water, can take place at temperatures up to 20 ° C, but higher temperatures of about 80 to 100 ° C, or even higher, are preferred. The appropriate temperature is also controlled by the viscosity ratios of the resulting mixture. Mixing can also take place in several stages.

According to the invention, the hydrolysis is carried out at temperatures of 160 to 235 ° C, preferably at 180 to 230 ° C. These proposed hydrolysis temperatures are based on the finding that the content of unhydrolyzed 1,4-alkanesultone in alpha-olefin sulfonates depends largely on the hydrolysis temperature, decreasing with increasing temperature. At temperatures around 150 ° C, alpha-olefin sulphonates contain about 3000 mg of sultones per kg of active substances, at 160 ° C only about 200 mg / kg, at 180 ° C about 20 mg / kg, then the content decreases only slowly at 200 ° C to about 10 mg / kg. at 230 ° C to about 7 mg / kg. At temperatures above 235 ° C, it was surprisingly found that even the sultone content increased and, for example, at 250 ° C, 20 mg / kg was found. At lower temperatures up to 150 - 160 ° C, the final sultone content is still considerably influenced by reaction times in technical conditions, so that hydrolysis times of between 10 and 30 minutes are expedient. At higher temperatures above 160 ° C, the rate of hydrolysis is already such that the necessary residence times are up to 10 minutes and this already means problems with production plant volumes. Another reason for utilizing the temperature ranges in the hydrolysis of the present invention is the new discovery that at higher temperatures the sulfosulfonate content of the products is reduced. Thus, in products hydrolyzed at 140 ° C, 9.5% of the sulfosulfonates of the total active substance content were found, whereas in products hydrolyzed at 190 ° C only 2.5% were found. Similarly, in the treatment of olefinic raw materials other than 1-alkene into olefin sulfonates, the dependence of the sulfonates and sulfosulfonates content on the hydrolysis temperature is similar. Thus, the sulphate sulphonates and sultones can be drastically reduced by the process of the invention.

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Even then, 120 ° C should not exceed 0.2 s.

Sulfonation can be carried out in a discontinuous manner by introducing an appropriate amount of sulfur trioxide in the form of a gaseous mixture into a liquid alkone into a liquid alkene vessel with good mixing of the phases and efficient cooling. In discontinuous sulfonations, it is preferable to use higher concentrations of sulfur trioxide, preferably between 5 and 15 mol%.

For continuous sulfonation, co-current systems in a reactor with film-reacting liquid on cooled walls or with intensively mechanically stirred co-current flow of liquid and sulfonation gas are most suitable. In continuous sulfonations, it is preferable to use lower concentrations of sulfur trioxide in the sulfonation gas, between 1.5 and 10 mol%. Continuous processes are preferable for higher throughputs and, in addition, achieve higher degrees of sulfonation than discontinuous processes. Thus, in the continuous sulfonation of 1-alkenes, 93-97% of the degree of sulfonation can be conventionally achieved, compared to 67-92% in the case of discontinuous sulfonation.

Air is commonly used as the inert gas for diluting sulfur trioxide, but may also be other gases or vapors or mixtures thereof that do not participate in the reaction with the reactants and products. Nitrogen, sulfur dioxide can be used very well. Crucial is *

mostly the price of gas and this is the main advantage of air. If the gases are recirculated, price issues are no longer so important.

In the process according to the invention, it is sulfonated with sulfur trioxide in an excess of from 2 to 35 moles. % versus alkene. The precise choice of the amount of excess depends on the efficiency of the chemisorption of SO, in the sulfonation plant, on the type of alkene treated and on the compromise choice between the level of sulfation and the color of the products. 1-Alkenes from paraffin wax cracking usually require excess sulfur trioxide of between 15 and 35 moles to sulfonate to a degree of conversion above 95%. %. The 1-Alkenes from the oligomerization of athylene require minor excesses, usually between 5 and 16 moles. %. Also the coloring of the products and the content of disulfonates in products produced on the basis of oligomerization 1-alkenes tends to be lower. The internal alkenes usually require excesses above 25 moles to achieve decent conversion. % sulfur trioxide.

In continuous sulfonations with short residence times of the reaction mixture, it is convenient to allow the sulfonation products to react for between 1 to 10 minutes. at temperatures of 20 to 45 ° C.

This results in the disappearance of 1,2-alkanesultones from the sulfonation products of the isomerization of 1,3- and 1,4-alkanesultones, and the sparingly soluble 1,2-hydroxyalkane sulfonates are then absent from the alkaline hydrolysis products. In some sulfonation plants, such post-reaction is already provided by a delay in the sulfonation gas separation apparatus from the sulfonation products. In the case of discontinuous sulfonations, the sulfonation time is always sufficient to effect these transformations.

In the process according to the invention, the sulphonation product is mixed with an aqueous alkaline hydroxide solution and a solution of a compound having a pH-buffering property, preferably with an alkaline salt of a polybasic acid prior to hydrolysis, the amount of alkali hydroxide being 0.9 to 1.2, 0.01 to 0.2 moles per mole of acid equivalents contained in the sulfonation product and released by hydrolysis. Mixing uses commercial, concentrated 30-50% sodium or potassium hydroxide solutions. Is possible

214,067 acidic equivalents contained in the sulphonation product and the hydrolysis releases which are conducted at temperatures of 160-235 ° C, preferably 180-230 ° C.

The new olefin sulfonate process is based on new discoveries in the study of sulphonation byproduction, sulphonation product behavior in alkaline hydrolysis, bleaching and pH adjustment, and is based on harmonizing new conditions to achieve a reduced proportion of unwanted by-products using a simple, easy process manageable and eliminates the shortcomings of the known processes.

Alkenes having a carbon number of 12 to 20, preferably in mixtures with a carbon number of 14 to 18 and having an average molar mass of from 200 to 250 g / mol, serve as raw materials for the production of the olefin sulfonates according to the invention. By limiting the composition of the alkenes, the proportion of low molecular weight alkenes is monitored, since it has been found that their sulfonation produces a higher proportion of undesired disulfonates. Sulfonation using the same molar excess produces about 3% disulfonates of surfactant sulfonates in the products of 1-dodecene sulfonation and hydrolysis, while only 7% disulfonates are formed from 1-octadecene. In alkene mixtures, the presence of lower alkenes causes their over-sulphonation and, in contrast, non-sulphonation of the higher alkenes. It is therefore preferred that the alkene mixtures do not differ greatly in the length of the carbon chain. The most suitable type of alkenes with respect to the application properties of the olefin sulfonates produced are linear 1-alkenes. These may be 1-alkenes produced by cracking paraffin waxes or 1-alkenes produced by oligomerization of ethylene. The cracked 1-alkenes are a mixture of even and odd number of hydrocarbons in the molecule, have a higher impurity content and give more colored products. 1-Alkenes from oligomerization have an even number of carbon atoms in the molecule, tend to have a lower amount of non-alkali, add lighter olefin sulfonates, and require a slightly lower excess of sulfur trioxide to sulfonate. Another type of alkene is 2-alkyl-1-alkenes, which are considered as a raw material for olefin sulfonates, especially in mixtures and linear 1-alkenes. These mixtures are the product of some combined oligomerization procedures. Also internal alkenes are usually processed as part of a mixture of alkenes with a predominant proportion of 1-alkenes. The internal alkenes themselves can also be processed by the process of the invention, but the products do not have as good application properties as olefin sulfonates based on 1-alkenes or mixtures with a predominant proportion of 1-alkenes,

Sulfonation of the alkenes is carried out at temperatures of 25 to 130 ° C, i.e. at temperatures where the alkenes are liquid, by treating with an excess of 1 to a concentration of 1.5 to 15 mol% of SOg by diluting with air or other inert gas gaseous sulfuric acid. O2 to 1.35 moles of SOg per mol of alkenes.

It is advantageous to keep the temperatures at the sulfone levels as low as possible, preferably at 25 to 50 ° C, as oxidation reactions and darkening of the products occur at higher temperatures. Due to the high reaction heat of sulphonation (AH * = -209 kJ / mol) and practically immediate reaction, it is necessary to ensure good conditions for dissipation of reaction heat during sulphonation and decompose the reaction to a longer time interval by gradual transport of sulfur trioxide into alkenes, respectively diffusion from the gas phase to the phase interface. On a production scale, there is almost always local overheating of the reaction mixture, but this must not exceed 120 ° C and the reaction mixture residence time at a maximum temperature between 80 to β

214 067 in 68 g of water. Mixing was carried out by noutralisation of free sulfone groups. Stirring was performed at a temperature between 60-80 ° C. For hydrolysis, the mixture was heated for 10 min. in an autoclave at 200 ° C and held at this temperature for 10 min. After cooling, the reaction mixture had a pH of 9.6. At 60 ° C, 11 g of a 15% sodium hypochlorite solution (containing 0.45% free sodium hydroxide) was added to the alpha olefin sulfonate solution and kept under stirring for 30 min. at 60 ° C. The dyeing of the products was measured according to the dye scale according to ČSN 58 0101. Prior to bleaching, the alpha-olefin sulfonate had a coloring degree of 16 after bleaching 14. 294 g of alpha-olefin sulfonate having a content of 30.8% (i.e. 88.1% of a. ) monosulfonates, 3.6% (i.e. 10.3% of a. 1.) disulfonates and 0.55% (i.e. 1.5% of a. 1.) sulfosulfonates. The content of alkanesultones was 9.5 mg / kg of active substances. Chlorinated sultones and unsaturated sultones were not detected in the product.

Example 2.

The sulfonation was carried out in a glass cylindrical reactor of 25 mm diameter and 380 mm length. The reactor was equipped with a flat glass stirrer, coiled into a helix and passing through the useful length of the reactor. Tempered water flowed through the reactor jacket. From the upper part of the reactor there was a tube for evacuating outlets. The sulphonating gas was introduced into the reactor through a 0.2 mm diameter bottom nozzle. Sulfur dioxide was dispensed from a syringe clamped into the jaw of a linear dispenser. The syringe needle was introduced through a rubber stopper into an obliquely descending, electrically heated vaporizer tube into a dry air stream, and an air stream was first introduced into the reactor at a rate of 4.4 liters / min. Then 68.7 g (0 · 3 mol) of the internal C ₁₅ to C ₁₈ internal molar mass of 229 g / mol were poured into the reactor and a 30 ° C warm water supply was connected to the reactor jacket. From the syringe was then into the vaporizer within 30 min. 30 g (0.375 mol) of sulfur trioxide were injected. The sulfonation product had a saponification number of 3.60 meq / g and contained 8.1% of unsulfurized alkenes, corresponding to 88% of the alkene conversion.

g of the sulfonation product was mixed with a solution of 7.3 g of sodium hydroxide in 50 ml of water and 0.23 g of NagHPO4 in 14 g of water at 60 ° C. This mixture was then heated to 180 ° C in an autoclave and hydrolyzed at -10 ° C for -10 min. After cooling, the reaction mixture had a pH of 10.4. Bleaching of the product was accomplished by the addition of 10 g of a 15% sodium hypochlorite solution (with a free NaOH content of 0.45%) at 60 ° C, maintained for 25 min. After bleaching, the olefin sulfonate solution had a pH of 10.5. Finally, its pH was adjusted to 8.0 by the addition of 2.6 ml of sulfuric acid with a concentration of 0.5H2SO4 = 0.5 mol. Olefinine sulfonate contained 29.4% (ie 78.5% of a. 1.) monosulfonates, 7.2% (ie 19.2% of a. 1.) disulfonates, and 0.8% (ie. 2.1) % of a. 1.) sulfosulfonate. It contained 37 mg of alkanesultones per kg of active substance.

Claims (1)

SUBJECT OF THE INVENTION A process for producing low alkene by-product surface-active olefin sulfonates by a process comprising sulfonating alkenes with sulfur trioxide gas, dilute air or other inert gas to a concentration of 1.5 to 15 mol% SO <at 25 to 120 ° C, alkaline hydrolysis of the products sulphonation, optionally bleaching and pH adjustment of the product, characterized in that for sulphonation of alkenes having a carbon number of 12 to 20, 214 067 preferably 14 to 18, with an average molar mass of from 200 to 250 g / mol, sulfur trioxide is used in an excess of 2 to 35 mol. % of the sulphonation product is mixed with an aqueous solution of an alkaline hydroxide and a solution of a compound having pH-buffering properties, preferably an alkali salt of a polybasic acid prior to hydrolysis, the amount of alkali hydroxide being 0.9 to 1.2, the amount of buffering compound 0, 01 to 0.2 mol per mol of acid equivalents contained in the sulfonation product and released by hydrolysis, which is then conducted at temperatures of 160 to 235 ° C. preferably at 180 to 230 ° C.