DE2355664A1 - CONTINUOUS SULFONATION PROCESS - Google Patents

Description

Continuous sulphonation process

The invention relates to a continuous sulfonation process, in which the exhaust gas from a previous sulfonation is used as cooling gas. Under the term "sulfonation" is used here and below to understand both the actual sulfonation and sulfation.

Sulphonation processes are usually carried out in such a way that a falling, thin, film-like stream of the organic material to be sulphonated is brought into contact with an SCU / inert gas mixture flowing in parallel. Even if the sulfonating agent "SO," is diluted with an inert gas in these customary sulfonation processes, the major part of the sulfonation takes place at an early stage of the reaction with intense heat development; , which leads to undesirable side effects, Z ₀ B ₀ a discoloration of the reaction product, a lowering of the degree of conversion and / or a mist formation in the exhaust gas. '

4/1 11

In order to counter the difficulties outlined, it is already known (cf. DT-OS 2 138 038 or Japanese Patent application 64486/1972) to carry out the sulfonation in such a way that between a thin film-like Stream of the material to be sulfonated and a (to) parallel flowing SO ^ / inert gas mixture an inert Cooling gas or a SO, -containing inert cooling gas flow is left. Although this measure admittedly leads to the occurrence of a temperature peak (to a early reaction time), contains the large amount of exhaust gases emerging from the reaction zone, similar to conventional continuous sulphonation processes, organic components (mist), unreacted SO ^ and the like, so that these exhaust gases are released into the air can only take place after expensive and laborious waste gas treatment and gas scrubbing because of the environmental pollution it causes.

It would therefore be highly desirable to recycle the off-gas in question into the reaction zone. The presence of water, mist and the like in the exhaust gas in question is undesirable because it thereby the quality of the sulfonates is impaired and the degree of conversion is reduced. Even if that the water and mist components of the exhaust gas are completely separated from it, however, remain (with regard to a successful recirculation of the exhaust gases in question into the reaction zone) is still sufficient technical and economic problems, so that such a return (of the sulfonation exhaust gases in the reaction zone) has not yet found its way into practice.

-3-

409824/11

The invention was based on the object of an economical to create working continuous sulfonation process, which leads to high-quality sulfonates with a high degree of conversion and recycling of the majority of the off-gases from the previous sulfonation (into the reaction zone) without larger equipment, effort permitted.

The invention is thus a continuous Sulphonation process, in which a thin film-like stream (s) to be sulphonated organic (s) Connection (s) with a parallel flowing SO - / inert gas mixture is brought into contact, which is characterized in that between the thin film-like Stream of the organic compound (s) in question and the SO / inert gas mixture flowing in parallel (to it) Exhaust gas from the (previous) sulfonation in 2 to 12 times the volume of SO, / inert gas = mixture as Cooling gas is recycled.

The exhaust gas resulting from a conventional continuous sulfonation process consists mainly of inert gas and a small amount of unreacted oil and SO ^. Although such an exhaust mist and the like contains, is the possibility of its reuse by recycling into the material zone or reaction zone conceivable. However, recirculation of such an exhaust gas into the material zone requires a separator or one Recovery system for the SO, or inert gas, whereby However, the device in question can be made very large due to the enormous volume of exhaust gas must, which of course is very expensive. ¥ enn on the other hand the exhaust gas directly as part of the SO2 / inert gas

-4- 409824 / 112Λ

is returned to the reaction zone of a customary continuous sulfonation process, was found become that the sulfonates obtained are considerably discolored. This is obvious to one sensitive change in the concentration of SO, attributed to the SCU / inert gas in the reaction zone.

In carrying out the process according to the invention in which the sulfonation is carried out in the manner is that the exhaust gas (from the previous sulfonation) as a cooling gas between a thin film-like stream of the material to be sulphonated and an SCU / inert gas mixture flowing in parallel is allowed to flow, the desired sulfonation can be achieved without any side reactions, with high quality Sulfonates are obtained.

According to the method according to the invention, for example, the most varied of olefins, namely dj -olefins, olefins with internal unsaturated bonds and olefins of the vinylidene type, each with 6 to 30 carbon atoms, alkylbenzenes with 8 to 15 carbon atoms, higher alcohols can be used as organic materials Sulfonate 8 to 24 carbon atoms, alkylene oxide derivatives of aliphatic alcohols having 8 to 22 carbon atoms, alkylene oxide derivatives of alkyl phenols having 8 to 15 carbon atoms, and the like. These organic materials are used in the form of a falling, thin, film-like stream. The temperature of this current at the time of entry into the reaction zone is generally between 10 ° and 45 ⁰ C, although it may also be even lower or higher, depending on the organic material used.

-5-409824 / 1124

The SO 2 / inert gas mixture used in the context of the method according to the invention can contain the SO 2 in a concentration of about 0.5 to 25% by volume. It contains, for example, air, nitrogen and / or carbon dioxide as the inert gas. At the time of entry into the reaction zone to the temperature of the SO, / inert gas mixture from about 20 ° to 50 ⁰ C, its speed about 20 to 100 m / sec, preferably about 30 to 80 m / sec, respectively. The gaseous SO to be used is obtained by treating the gases produced when burning sulfur in an SO ^ converter or by evaporating liquid SO ,.

The process according to the invention can be used in any film sulphonation apparatus, for example of the double cylinder type and / or of the flat plate type '.

That to be recycled in the context of the method according to the invention Exhaust gas is obtained by separating off the sulfonation product, which consists mainly of sulfonic acid after the sulfonation with the aid of a conventional gas / liquid separator. Because this exhaust in the frame of the method according to the invention is used as a cooling gas, the formation of mist is under simultaneous Decrease in the amount of unreacted SO, greatly reduced. In other words, the amount of 'Nebe ^ and SO ·, in the exhaust gas - although from material to material different - at most 1.8 mg / 1, usually less (fog) and at most about 50 ppm (SO,). This exhaust

is about as humid as the SO ^ / inert gas mixture and has

ο
a dew point below -50 C. In this context, it should be pointed out that at dew points of over -4 ° C

-6-409824 / 1124

Desired phenomena occur, for example, a decrease in the degree of conversion, an increase in the content of HpSO-ira reaction product, an increase in the mist in the exhaust gas, an increase in colored substances and the like. Although the temperature of the exhaust gas may vary depending on the temperature of the sulfonation reaction, it is generally between about 10 ° and 4O ⁰ C. Since it, to serve as cooling gas must have a temperature of about 4O ⁰ C, it may be cooled down to this temperature at the time of its use. The speed of the exhaust gas at the time of introduction into the reaction zone expediently corresponds to the speed of the flowing SO 2 / inert gas mixture or can be up to about 1 / 1.4 times the speed of the flowing SCu / inert gas mixture As a rule, the exhaust gas used according to the invention contains only a small amount of mist or mist, so that sulfonates of excellent quality are obtained even without the mist or mist being deposited. However, if a material to be sulfonated is assumed that leads to the formation of exceptionally large quantities of mist, it becomes necessary to separate the mist or mist. The mist, mist or dust can be separated off, for example, by filtration, by electrical precipitation work, by centrifugal separation, by absorption / desorption processes using solvents and the like. Examples of devices suitable for this purpose are Cottrell precipitators and glass filters.

As part of the procedure. According to the invention, the amount of exhaust gas serving as cooling gas must be about Z to 12 times, preferably about 2 to 7 times the volume amount

-7-409824 / 1124

- ■ 7 -

of the SO ^ / inert gas mixture. Hence the The main part of the exhaust gas from the previous sulfonation is consumed as cooling gas, the rest of the exhaust gas is used after removal of the mist contained therein or Dust with the help of a simple treatment device, e.g. in an absorption tower filled with alkalis " released into the air »When the amount of as cooling gas serving exhaust gas is less than about 2 times the total amount is due to the SO2 / inert gas mixture used, the occurrence of the temperature peak described do not avoid. When the amount of the exhaust gas serving as the cooling gas is more than about 12 times the total amount on the SO2 / inert gas mixture used is the contact between the organic material and the SO ^ at a (desired) contact point is insufficient, so that, for example, the reaction process is inhibited or slowed down,

It is possible, within the framework of the procedure according to the. Invention serving as a cooling gas exhaust gas, based on the Total amount of SO 2 required to carry out the reaction, about 1 to 20, preferably about 3 to add up to 15 wt .- ^ o SO ^ ,, This SO, addition should take place before the start of the sulfonation reaction.

When carrying out the method according to the invention, the following results can be expected?

1 ο Because a considerable part of the cooling gas is used Exhaust gas can also serve as a substitute for the inert gas, the amount of in the reaction zone in the form of a SO, / inert gas mixture. inert gas to be introduced can be drastically reduced. Consequently, you can't

409824/1124

just different pretreatment devices for the inert gas, namely the drying device, the air blower and the mist or dust filter, can be dimensioned considerably smaller, it can also be on the drying device for the exhaust gas per se can be dispensed with.

2. Since most of the off-gas from the previous sulfonation is consumed as cooling gas in the reaction zone is, the amount of exhaust gas to be released into the air is significantly reduced, which is why the outlet devices for the exhaust gas compared to known sulfonation processes at the same time Easier removal of the exhaust gas can be dimensioned far smaller and greatly simplified can.

3. Since the content of the mist in the exhaust gas is low and the mist is dissolved or enriched in the sulfonation product the yield of the end product is increased, although this is qualitative is at most slightly impaired and directly put into practical use can be. The same results can be obtained here even with long-term, continuous sulfonation expect.

4. Depending on the amount of SO contained in the exhaust gas, leaves the amount of that contained in the SCU / inert gas mixture SO, lower it further.

The following examples are intended to demonstrate the method according to Illustrate the invention in more detail.

-9- 409824/1124

example 1

An organic material was found to be too sulfonating oC-olefin obtained by polymerization of ethylene with 14 carbon atoms used. The sulfonation took place in the reactor described below the reaction conditions given below. The cooling took place outside the reactor.

Reactor:

Thin film sulfonation device of double cylinder type, length: 2 m, distance between inner and outer .reaction area: 5.5 mm, feed speed of the material to be sulfonated: 70 kg / h

Molar ratio SO to the organic material: 1.10 SO / inert gas mixture:

. 1.48 volume- ^ SO, containing air Feed rate: 0.8 Nm / min

Cooling gas:

Air containing 0.3% _{by volume of SO 5} (ie 4.5% by weight of the total amount of SO 1 to be used). Feed rate: 2.2 Nm- ⁵ / min. Temperature: 25 ° C

Velocity of the SO2 / inert gas mixture and of the cooling gas at the time of introduction into the reaction zone (linear speed): 66 m / sec Cooling water temperature: 20 ° C »

The obtained sulfonate was from the exhaust gas with the help of a Gas / liquid separator disconnected. Under otherwise constant reaction conditions, 10 hrs continuously sulfonated, with 73 volume-? 6 of the

-10-409824 / 1124

separated, originally 45 C warm exhaust gas after cooling down were returned to 25 ° C with the aid of a circulation fan as cooling gas in the reaction zone. The not al The remaining part of the exhaust gas used for cooling gas was filtered through a glass filter in an alkali-charged one Tower washed and then released into the air. After the sulfonation, the exhaust gas contained about 1.7 mg / l mist or 30 ppm SO ,.

In another continuous sulfonation process, a glass filter was attached to the rear as a mist catcher. end connected to the air / liquid separation device in the exhaust gas recirculation device used in the present case (The results of this sulfonation procedure are shown in Table I below).

For comparison purposes, the same continuous sulfonation was carried out under otherwise constant conditions for 6 hours carried out for a long time using cooling air containing SO ^, However, the exhaust gas from the previous sulfonation was not allowed to circulate (comparative example 1). The results of this sulfonation can also be found in the following table I.

Table I.

Properties of the end product Method comparative according to example 1 invention

Content of unreacted oil 2.12 2.05 (petroleum ether extract) (active (o rsi \ basis) in% by weight ^u » ^{u (}}

Coloration (in 5% concentration) 0.170 0.095 Absorbance: 10 mm cuvette, 420 inii (0.095) Content of inorganic salts 6.5 6.1 (active basis) in% by weight (5.9)

409824/1124 ~ ¹¹ ~

Example 2

The sulphonation was carried out as in Example 1 except that an alkyl benzene used instead of the <L-olefin having a molecular weight of 243, a molar ratio 'SO selected to organic material of 1.05, the temperature of the cooling water at 25 ⁰ C and .eingestellt finally, no SO was added to the exhaust gas serving as cooling gas. Comparative example 1 was also repeated after a corresponding modification. The results compiled in Table II below were achieved (the values in brackets were obtained when a mist or dust collector was switched on in the exhaust gas recirculation system).

Table II

Properties of the end product Method comparative according to example 2 invention

Unreacted oil content 1.34 1.20

(Petroleum ether extract) (active

Basis) in% by weight (1.18)

Coloring (in 5% concentration) 0.015 0.012 Absorbance: 10 mm cuvette, 420 mu (0.013) Inorganic salt content 1.02 0.75 (active base) in% by weight (0.86)

Example 3

The sulfonation was carried out as in Example 1, but with the condensation product as the organic material to be sulfonated of a CLp alcohol with 3 moles of ethylene oxide, (molecular weight: 326), the molar ratio SO, adjusted to 1.03 for organic matter

-12- 409824/1124

and finally the exhaust gas serving as cooling gas no SO ^ was added. After appropriate modification by v.iirde Comparative Example 1 was also repeated. The results obtained are shown in Table III below compiled (the values in brackets apply in the event that a mist or Dust collector has been switched on).

Table III

Properties of the end product Method Comparative

according to the example invention

Unreacted oil content 2.10 x 2.17 (Ion exchange process.) (Active (2.15) basis) in% by weight

Coloration (in 5-6 concentration) 0.014 0.012 Absorbance: 10 mm cuvette, 420 mu (0.012) Content of inorganic salts 0.76 0.30 (active basis) in weight yo (0.52)

Example 4

The continuous sulfonation was carried out as in Example 1, but with the organic material to be sulfonated a synthetic alcohol with 12 carbon atoms is used, the molar ratio SO, to organic material set to 1.03 and no SO ^ was added to the exhaust gas serving as cooling gas. According to the appropriate Modification, Comparative Example 1 was also repeated. The results thereby obtained are as follows Table IV (the values in brackets apply to the case that in the gas recirculation system a mist or dust collector has been switched on).

-13-

409824/1124

Table IV

Properties of the end product Method comparative according to example 4 Inventive

Content of unreacted oil 2.51 2.74 (petroleum ether extract) (active '(2.34) basis) in % by weight

Coloration (in 5% concentration) 0.013 0.12 Absorbance: 10 mm cuvette, 420 mu (0.013)

Content of inorganic salts 0.87 0.45 (active basis) in% by weight (0.57)

-14-40-.9824 / 112A

Claims (3)

2355864 Claims / 1.j Continuous sulfonation process in which ^ - a thin film-like stream (s) to be sulfonated organic compound (s) in contact with a parallel flowing SO - / inert gas mixture is brought, characterized in that between the thin film-like stream of the relevant organic compound (s) and the parallel (to it) flowing SO ^ / inert gas mixture the exhaust gas from the (previous) Sulphonation in 2 to 12 times the volume of the SO, / inert gas mixture recycled as cooling gas will. 2. sulfonation process according to claim 1, characterized in that that the exhaust gas, based on the total amount of SO · ,, required for sulfonation, about 1 to 20% by weight SO- is (are) added. 3. sulfonation process according to claims 1 and / or 2, characterized in that the temperature of the exhaust gas fed into the reaction zone 10 ° to 40 ° C, the speed of the exhaust gas introduced into the reaction zone about 20 to 100 m / sec and the temperature of the in the reaction zone is introduced S0, / inert gas mixture is about 20 ° to 50 ⁰ C, and that the velocity of introduced into the reaction zone SO ^ / inert gas mixture corresponds to the speed of the exhaust gas and extend up to about 1.4 times the speed of the exhaust gas can. 4 * sulphonation process according to one or more of the preceding claims, characterized in that -15- 409824/1124 the organic compound is an olefin with 6 to 30 carbon atoms, an alkylbenzene with 8 "to 15 carbon atoms, an aliphatic alcohol with 8 to Carbon atoms, an alkylene oxide derivative of an aliphatic alcohol containing 8 to 22 carbon atoms and / or an alkylene oxide derivative of an alkylphenol having 8 to 15 carbon atoms is used and that Inert gas consists of air, nitrogen and / or carbon dioxide. 409824/1124