DE899801C - Process for the continuous sulfonation of alkyl aromatics - Google Patents

Description

Process for the continuous sulfonation of alkyl aromatics Zur continuous sulfonation of alcohols, olefins, aromatics or alkyl aromatics with sulfuric acid, fuming sulfuric acid or other sulphonating agents known per se you can use agitator vessels, in which the reactants continuously flow in and from which continuously a corresponding proportion of the reaction mixture is removed. Despite the long residence time of the starting materials to be sulfonated contains the mixture leaving the agitator container always more or less large Fraction of non-sulfonated products. This fact not only diminishes that Yield, but also the quality of the sulfonated material. By using of several agitator vessels through which the reaction mixture flowed through one after the other have to be, you can. largely avoid these disadvantages. But there is one for this cumbersome manufacturing facility required, the relatively high investment costs caused. Continuous sulfonation processes can also be carried out in a vertical, with packing, e.g. B. carry out reaction tube provided with Raschig rings, in: that from above continuously a suitable sulfonating agent and from below the starting material to be sulfonated is introduced. The source material rises continuously in this reaction tube with the sulfonation products which are formed to the top, where it can be continuously withdrawn (. The excess sulfonating agent collects itself at the lower end of the reaction pipe and is from there in a more suitable way Way away.

For better mixing of the reactants one can in such Sulphonation devices from below, in addition, a gas stream in such an amount blow in that the hydrostatic flow direction of the starting material and the sulfonation products formed is retained. The advantage of one ider-like hydrostatic. Sulphonierungsprozes.ses consists in that an extraordinary simple apparatus can be used. In addition, the .Sulfonation formed by-products, ie the sulfonation product in an undesirable manner usually to dye, from the excess, in the countercurrent flowing su: lfonierungsmittel, for example from the concentrated sulfuric acid used, washed out and removed at the lower end of the reaction tube with the sulfonating agent flowing off. As a result, the sulfonation products have a lighter color than the Sulphonation in batch or continuous agitator vessels. For the production of high quality. Laundry detergents is the achieved lightening of the Color of particular advantage.

Vertical, through which the starting material flows hydrostatically However, reaction containers have the disadvantage that when viscous products such as they are only formed by sulfonation of starting compounds with a higher carbon number difficult to achieve a quantitative implementation (can. A sufficiently complete Under these circumstances, sulfonation of the starting material can usually only be done with a very high excess of sulfonating agents can be achieved, which means additional costs caused.

It has been found that there are these disadvantages with the continuous Avoid sulphonation of alkylaromatics if you first carry out the sulphonation as far as possible without countercurrent and then, idaran in one downstream, vertical reaction vessel: the one below that is already largely sulfonated starting material and above the sulfonating agent flow in countercurrent completed. The section of the continuous sulfonation to be carried out without countercurrent can be stored in an agitator vessel or in reaction vessels, e.g. B. in two perpendicular standing cylindrical vessels, through which the reaction mixture is circulated continuously with the help of a centrifugal pump. The reaction vessel, in which the final section of the continuous sulfonation is carried out expediently with suitable packing and at its lower end with a device for blowing in gases.

In the drawing are two for carrying out the invention Process suitable devices shown for example.

It is an agitator tank provided with a heating or cooling jacket (Fig. I), in which through line 2 the starting material to be sulfonated and through Line 3; the sulfonating agent runs in. Both respondents are through .the agitator is intensively mixed with one another.

The amount of starting material flowing in per unit of time is directed after the required time in the container i. This is generally i up to 3 hours, but can optionally be extended or shortened as required will.

Through an overflow line 4 a mixture of sulfonated Products, unreacted starting material and excess sulfonating agent passed into a Absetzronr 5. The content of non-sulfonated components of the The starting material generally amounts to 10 to 300 / a.

The excess sulfonating agent separates in the settling zone 5, which in most cases contains the water formed during the sulfonation, of Iden largely sulfonated products. The sulfonating agent is at the bottom of the Absetzronres 5 withdrawn through a line 6, while the upper layer through line 7 passed to the lower end of the vertical tube 8 provided with packing elements will. The packing tube 8 is also provided with a jacket through which the heater or cooling media can be conducted. At the top of the packed column 8 is abandoned the sulfonating agent through a line 9. By line io -will from the lower end at the same time a sufficient amount of air or other Gases blown in.

The sulfonation mixture fed in through line 7 rises within The packed column filled with sulphonating agent goes up and leaves after about 3o to i20 minutes the pipe 8 through a line ia :. The pipe i i is above the filling body surface is attached to a filling body-free calming area.

The sulfonation product flowing out of tube i i is practical quantitatively sulfonated, d. H. it contains practically no non-sulfonated components more.

Also at the lower end of the reaction tube 8 is a packing-free one Calming room 12 available. This is where the excess collects, through conduction g of abandoned sulfonating agents. Since there are only the relatively small proportions sulfonated on non-sulfonated products of the mixture fed in through line 7 it is only used a little. By a pump 13 it is therefore with the help the line 3 in the Rünrwerk container i transferred to carry out the main part of sulfonation to be used.

Sometimes an exact separation can be made at the bottom of the reaction tube 8 between excess sulfonation agent and sulfonation mixtures only with difficulty 'carry out. A return of sulfonation mixtures to the agitator tank i is beneficial at times. If you have the same or a slightly larger volume, as it enters as a sulfonating agent through line 9, at the bottom of tube 8 discharges, then leads .man thus a sufficiently large amount of excess sulfonating agent back to the plant container i.

Essential for good conversion and good utilization of the sulfonating agent is the use of a fast rotating stirrer, so within of the container i good mixing of the reactants is achieved.

Instead of using an agitator device, the mixing can be carried out the reactants can also be carried out with the aid of a pumping device. One for this -suitable device is shown schematically in FIG.

The centrifugal pump 15 sucks in the sulphonated material through a line 14 Starting material and at the same time through line 16 the sulfonating agent, wherein within the pump already an intimate, largely leading to emulsion formation Mixing of the reactants occurs. Within two reaction vessels ig, which are connected to a closed system with the help of pipelines, is: the reaction mixture is continuously circulated with the aid of the pump 15. The reaction vessels ig are provided with a jacket space through which heating or cooling media are passed to maintain a constant reaction temperature. Instead of Reaction vessels 1g can also contain pipe coils or pipe bundles of any type be used. In any case, however, the rate of circulation of the reaction mixture must be so big. that a turbulent flow occurs and a separation of the reaction mixture cannot occur. In general, speeds that are somewhat sufficient for this are above 4.o cm / sec, but you will: the required speed of rotation determine beforehand for each case by means of appropriate tests. The residence time of the starting material entering through line 14 in .das circulation system is in generally between 1 and 3 hours, but it can be extended as required or shortened.

Through line 17, the circulation system is continuously a, the through Line 14 introduced feedstock and the amount introduced through line 16 volume of sulfonation mixture corresponding to sulfonation agents through overflow deducted. During this withdrawal, the participants in the transaction must not yet segregate occur so that the withdrawn volume in its composition exactly the continuous corresponds to the pumped reaction mixture.

The reaction mixture withdrawn through line 17 is poured into a settling tube 18 transferred. The excess sulfonating agent separates at the bottom of this Vessel aab and is removed through line 2o. As the upper layer divide the sulfonation products and the not yet sulfonated fractions of the starting material away. By line 21 this upper layer is the lower end of a vertical tube provided with fillers, 22 .zuführ, into the from above through a line 23 the fresh sulfonating agent enters, wherein at the lower end of the tube 22 through a pipe: 24 air or other gases can be blown in.

The proportions still to be sulfonated increase within the tube 22 and the already sulfonated fractions of the starting material upwards. From the top They are made up as the end product Line 25 withdrawn. The excess sulfonating agent fed in through line 23 collects in the lower calming space 26 and from there becomes common if necessary with sulfonation mixture through the already mentioned line 16 from the centrifugal pump 15 returned to the sulfonation cycle circulating through the vessels.

Through the procedure according to the invention, the sulfonating agent used is d. H. for example a 100% sulfuric acid. in an extraordinarily good way exploited. The freshly flowing acid is used in the packing tubes 8 or 22 initially to work up the last unconverted portions of the starting material. As a result of the countercurrent principle used, the sulfonation products that run off occur finally with the: very fresh, not yet diluted acid in contact. First then the acid is used in the agitator tank i or in the circulation system ig the main proportions of the starting material used only then at the lower end of the A. settling pipes 5 or 18 repelled as used acid, mostly diluted with water to become. In this way you can do the sulfonation with one relatively only carry out a small excess of sulfonating agent, for example sulfuric acid, which is not possible when only filling vessels 8 or 22 are used. A particular advantage here is that the, fresh acid from the continuously outflowing sulfonation product can wash out the coloring by-products, so that practically uncolored end products are obtained. Example i In one with overflow provided glass flasks with a capacity of 51 are 1.71 monoalkylbenzene and the hourly mixture of sulfuric acid withdrawn from the bottom of a downstream packing tube and sulfonation mixture introduced and with the help of a corrosion-resistant fast rotating Stirrer intimately mixed with one another. The monoalkylbenzene was composed of C12 monochloride and benzene in the usual manner. .By a water bath the reaction temperature was kept at 75 °.

The product flowing out of the overflow got into a settling pipe made of glass with a clear width of 30 mm and a height of 50 cm, which was kept at 75 ° by a water jacket. Here the excess sulfuric acid separates from the largely sulfonated starting material, 0.5 liters of excess sulfuric acid with 8go / o H2S04 content being drawn off every hour at the lower end of the settling tube. The upper layer was placed in a vertical glass tube with a clear width of 50 mm and filled with glass rings of 5 mm diameter: to a length of zoo cm. This glass tube had a sedimentation space free from packing at the top and bottom and was surrounded by a jacket space through which hot water flowed, keeping the packing tube at a temperature of 75 °.

The starting material, which was already largely sulfonated, was introduced at the lower boundary surface of the packed column, while 11,980% sulfuric acid per hour was added to the upper boundary surface of the packed column. At the same time, 751 air per hour were blown in from below. The sulfuric acid not used for sulfonation collected on the floor of the lower calming room. From here, 1.2: 1 products were withdrawn every hour, which consisted of 0.61 of 92-1 / aiger sulfuric acid and 0.61 of a mixture of monoalkylbenzene and sulfonic acid. The mixture was fed to the above-mentioned glass flask. The finished sulfonation product ran off from the upper calming chamber.

After leaving the glass flask equipped with a stirrer contained the sulfonation mixture still has 21% unreacted starting material. The end The sulfonation product running off the packing tube only contained 0.5-1 / o converted proportions and was light yellow in color. By neutralization, evaporation and drying could from this in a manner known per se a pure white: Mkylarylsulfonat are obtained, which only contained o, 2-1 / o uranium-saponified components. B. Eggsnel 2 6.31 monoalkylbenzene were poured into the suction port of an acid-proof centrifugal pump every hour the method of manufacture used in example i and the one at the bottom of a downstream Packing tube withdrawn mixture of sulfuric acid and sulfonation mixture introduced. The centrifugal pump had an output of 10,000 1 hour and pressed the mixture of the two reaction participants through two internally enamelled tubes of 8o mm clear width and 20o cm height each, which are arranged vertically and at the top, through a pipe were connected to each other. Outside were the enamelled pipes surrounded by a jacket space through which they can be heated to 75 ° with the help of hot water were held.

The centrifugal pump delivered the reaction mixture through one pipe from the bottom to the top and then through the other pipe from the top to the bottom, whereupon the mixture returned to the suction nozzle of the centrifugal pump. At the upper connecting tube of the two enamelled reaction tubes, as much liquid was continuously drawn off as the centrifugal pump of monoalkylbenzylbenzene and sulfuric acid flowed into it. The mixture withdrawn from the circuit passed into an acid-proof lined on the inside, temperature-controlled at 75 °, settling pipe with a clearance of 5.0 mm and a height of 100 cm. From this settling pipe 1.2.1 sulfuric acid with a content of 88-1 / a H2 S 0 was withdrawn as a lower layer every hour. The upper layer of the sedimentation pipe got into a sensory enamelled, vertical pipe with a clear width of 80 mm and filled with porcelain knuckles of 5 mm in diameter over a distance of 3100 cm , which had a water jacket heated to 75 ° and below and above each a filling body-free calming chamber . The sulfonated product was introduced at the lower boundary surface of the packing layer, while 3.71 sulfuric acid per hour with a content of 98% H 2 SO 4 was added to the upper packing boundary area. At the same time, Zoo 1 air was introduced every hour from below.

The sulfuric acid not used for sulfonation collected in the lower container space of the packed column and was fed back into the suction port of the centrifugal pump 15 in an amount of 1.91 liters per hour, together with a mixture of sulfonic acid and monoalkylbenzene per hour, while from the upper one Container space from which the sulfonation product formed ran off. It was light yellow in color and had less than 0.5-1 / o non-sulfonated components. In contrast, the product withdrawn from the circulation system of the centrifugal pump still contained 28-1 / o non-sulfonated fractions. A pure white alkyl aryl sulfonate containing less than 0.2-1 / o urine-saponified constituents could be produced from the sulfonation product by neutralization, evaporation and drying.

Claims (3)

PATENT CLAIMS: i. Process for the continuous sulfonation of Alkyl aromatics with sulfuric acid or other suitable sulfonating agents, thereby characterized in that the sulfonation is initially as largely as possible not in Executes countercurrent and then it in a downstream vertical standing Reaction vessel, the already largely sulfonated starting material and below Above, the .Sulfonating agent flow in, ended in countercurrent. 2. Procedure according to Claim i, characterized in that the sulfonation takes place in an agitator vessel (i) started and ended in a vertical, packed tube (8) by adding the sulfonating agent to the head (9) of the packed column (8), takes off at its lower end (12) and transferred from there to the agitator tank (i), in which the starting material to be sulfonated enters continuously (2), wherein Part of the sulfonation mixture flows continuously from the agitator tank (i) and into a settling vessel (5), at whose .oberem end (7) that is already largely sulfonated starting material removed and the lower end of the packing tube (8) is added while, the unused sulfonating agent at the bottom End (6) of the settling tube (5) and the sulfonated end product at the the upper end of the packing tube (ii) emerges. 3. The method according to claim i, characterized characterized in that the sulfonation is started in reaction vessels (i9) by which one circulates the reaction mixture continuously with the aid of a pump (i5) and is terminated in a vertical, packed tube (22) by the Sulphonating agent at the top (23) of the packed column (22) in Aden process cycle enters, withdrawn at the lower end (26) of the same and with the to be sulfonated Starting material (i4) enters the suction port of the circulation pump (i5), with the Circulation of the reaction mixture continuously removed a part (i7) and a settling tank (i8) is fed, at the upper end (2: i) i the already largely sulfonated Starting material withdrawn and fed to the lower end of the packing tube (22) is, while the unused sulfonating agent at the lower end (2o), des Settling tube and the sulfonated end product at the upper end (25) of the packing tube (22) drains. Referenced publications: German patent specification No. 722 59o.