DE2108902A1 - Dialkyl sulphides prepn - from alkali alkylmercaptide and alkyl halide in reactor filled with spherical bodies - Google Patents

Abstract

Dialkyl sulphides (esp. omega-hydroxy-dialkyl sulphides) are prepared by reacting alkali alkylmercaptides (esp. alkali hydroxyalkylmercaptides) with alkylhalides that are gaseous under the reaction conditions in a recator filled with spherical bodies (diameter pref. 4-20 mm) at 40-120 degrees C and 0-5 atm (gauge). Practically no longitudinal mixing of the reaction mixture takes place, so that only a single reaction chamber is required. Rate of reaction is higher than in prior procedures and space-time yields are high.

Description

Production of Dielkylsulfiden The conversion of alkyl halides with # -oxyalkyl mercaptans in alkaline solution is known [J. am. soc. 74/828 (1952); Reid, Organic Chemistry of Bivalent Sulfur Vol. 2/206 (1960); US 2806 8B4 (1957); DAS 1,270,550 (1968); DOS 1,568,215 (1970)]. A particularly simple manufacturing process is characterized in that the alkyl halide and alkali mercaptide are discontinuous reacted with one another in aqueous solution, preferably alkyl chloride with sodium mercaptide.

If this process is to be carried out continuously, it must be expediently carried out work in such a dilution that the resulting sodium chloride from the aqueous Phase after the reaction does not fail (compare DAS 1 270 550 - column 2 -line 45). This means that a large reaction volume has to be dealt with and the Space-time yield is bad.

An efficient, continuous process is not yet available described.

It has now been found that significantly better space-time yields can be obtained Achieved that also exceeds those of the above-mentioned, more concentrated working discontinuous Manufacturing processes lie if one considers the continuous reaction of alkaline Aqueous oxyalkyl mercaptan solution with excess alkyl halide in a ball-and-pile reactor can run off under pressure.

The subject of the present invention is thus an experienced for manufacturing of dialkyl sulfides, in particular oxydialkyl sulfides, by reaction of alkali alkyl mercaptides, in particular Alali-oxyalkylmercaptiden, and alkyl halides, which under the reaction conditions are gaseous, characterized in that the reaction in the pebble heap reactionfor at temperatures between 400 and 1200 C and at the printer; between 0 and 5 atm.

The pebble bed reactor, as it is described in more detail in Example 3, offers the advantage, in the case of continuous operation, that, in contrast to conversions in columns with packing of a different type, when using according to the invention small balls practically no longitudinal mixing occurs. So it can be in one single reaction chamber can be worked.

It is advisable to use balls with a diameter of 4 to 20 mm.

The special effect of using a ball pile reactor according to the invention in the present case, however, lies in a considerable increase in the rate of reaction compared to the previous continuous process; this increase was not easily predictable.

The reactor also offers an advantage over those equipped with agitators Reaction vessels have the further advantage that no sensitive, fast-running Stirring mechanisms are necessary, which also easily leak when subjected to pressure.

The reaction is carried out at an elevated temperature between 40 and 1200 C, preferably carried out between 60 and 1000.degree. The pressure in the apparatus can between 0 and 5 atmospheres.

The concentration of the aqueous mercaptide solution becomes appropriate chosen so that that resulting from the reaction Alkali halide remains in solution.

Suitable alkyl halides for the process are e.g. B.

Echyl chloride, methyl bromide, methylene chloride, ethyl chloride, ethyl bromide and allyl chloride; suitable ß-oxylalkyl mercaptans are ß-oxyethyl mercaptan γ and β-oxyalkyl mercaptan.

However, the process can also be carried out with unsubstituted alkyl mercaptans e.g. with ethyl mercaptan and also with other substituted alkyl mercaptans such as e.g. carry out monothioglycerin.

In the case of continuous operation on a larger scale, it is expedient the excess haloalkyl, which is necessary to maintain the effervescent effect is, possibly after relaxation and subsequent compression, back into the reaction zones returned.

The effect of the procedure is best from the table below visible: pressure reaction space-time yield reactor type atü temperature ß-Oxydiethylsulfid 0 700 10 g / l / h stirred tank with Hoesch stirrer 800 rpm.

O 700 40 g / l / h pebble bed reactor 0 800 52 g / l / h "1l 1 70 ° 30 g / l / h stirred kettle with Hoesch stirrer 800 rpm.

1 70 ° 68 g / l / h pebble bed reactor 1 800 110 g / l / h "" 1 90 ° 146 g / l / h "" 1 1000 183 g / l / h "2 70 ° 81 g / l / h" "2 900 197 g / l / h lt" 2 1100 219 g / l / h "lt The details are from the examples below evident.

Example 1: Two V4A stirred tanks with a capacity of 5 liters are used as a cascade connected in series. Both are equipped with a Hoesch stirrer and jacket heating. A mixture of 81 g thioglycol (96% / 1%) is poured into the first stirred tank every hour Mol), 8G concentrated sodium hydroxide solution (50% strength / 1 mol) and 160 g of water are fed in. Gaseous chloroethyl is introduced into both containers in such a way that there is always a small amount Overpressure of 500 mm water column is maintained. The stirring speed is 800 rpm, the reaction temperature is 700 C. From the second stirred tank the reaction mixture is continuously fed out depending on the level. It fall every hour 120 g crude oil with a content of 85% ß-oxydiethyl sulfide (gas chromatography) and 265 g of aqueous lower lye. The residual thioglycol content of the lower liquor is 0.3%. The conversion is therefore 99%. 120 g of crude oil are transformed into a simple fractional distillation (fraction: 80 - 900/18 mm) 100 g of pure ß-oxydiethyl sulfide won (bp .: 181 - 1820/760 mm; density D20: 1.0175; refractive index n20: 1.4867). The 4 D yield is 94 0S, the space-time yield 10 g / l / h /.

Example 2: A mixture of 245 g thioglycol (96% / 3 mol), 240 g concentrated sodium hydroxide solution (50 noig / 3 mol) and 480 g of water pumped in every hour. In the second container is with the help of a Dosing pump liquid chloroethyl pumped in so that a pressure of 1 atm in the system is maintained. The second stirred tank is with the first stirred tank connected by a gas displacement device. The curing temperature is again 700 C, The stirring speed is 800 rpm. From the second Rücrkessel are hourly 375 g crude oil and 794 g aqueous base liquor fed out depending on the level. That contains crude oil 80% ß-Oxydiethylsulfid, the lower liquor has a residual thioglycol content of 0.2 96, which corresponds to a conversion of 99.3%. From the crude oil one gets through a simple fractional distillation 293 g of ß-oxydiethyl sulfide, corresponding to a yield of 92%.

The space-time yield is 30 g / l / h.

Example 3: A 175 cm long V4A pipe with a heating jacket and 4 cm inner Diameter is 125 cm high filled with e mm ceramic balls. At a height of 25 cm Chlorethyl introduced in gaseous form, the thioglycolate solution at a height of 150 cm. On the At the top of the pipe there is a reflux condenser with a downstream expansion valve, At the lower end of the pipe, the finished product is raised over a 125 cm overflow and alternately switchable collecting vessels removed. The pipe capacity is 2200 com, the actual reaction space between the balls 560 com. Parallel to the reaction tube a level measurement is switched on. The reaction tube is continuous during Tests according to the height of the overflow with the finished reaction mixture, and mainly filled with the resulting crude oil through which the thicglycolate solution falls down and the gaseous chloroethyl bubbles through it, finely divided. In the The tests listed in the table below were carried out in the same proportions of Examples 1 and 2, a 24% thioglycolate solution is used. The amount of chloroethyl was measured in such a way that, in addition to the amount necessary for the reaction, there was a sufficient excess was there to achieve a sufficient effervescence.

Pressure temp. Input / h conversion decrease / ß-Oxydiethyl-Raum-Yeit- yield atü thioglyco / h crude oil sulphide accumulation yield lat solution / h 0 70 ° 300 g 99.0% 105 g 89 g 40 g / l / h 90.5% 0 80 ° 385 g 99.5% 134 g 114 g 52 g / l / h 91.0% 1 70 ° 490 g 99.5% 188 g 150 g 68 g / l / h 94.0% 1 80º 820 g 99.3% 304 g 244 g 110 g / l / h 91.0 % 1 90º 1070 g 99.5% 387 g 322 g 146 g / l / h 92.0% 1 100º 1330 g 99.3% 493 g 404 g 183 g / l / h 93.0% 2 70 ° 757 g 99.0% 254 g 178 g 81 g / l / h 95.0% 2 90 ° 1300 g 99.5 % 546 g 434 g 197 g / l / h 93.0% 2 100º 1300 g 99.3% 566 g 481 g 219 g / l / h 90.0%

Claims (1)

Claim: Process for the production of dialkyl sulfides, in particular oij-Oxydialkylsulfiden, by reaction of alkali alkyl mercaptides, in particular from alkali oxyalkyl mercaptides, and alkyl halides, which under the reaction conditions are gaseous, characterized in that the reaction is carried out in the pebble-bed reactor at temperatures between 40 and 1200 C and at pressures between 0 and 5 attt.